THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA LOS ANGELES //10 ' 3 {fivi/MU r //, ' /<; S I R I S: A CHAIN of PHILOSOPHICAL REFLEXIONS A N D INQUIRIES Concerning the V i R T u E s of TAR WATER, And divers other SUBJECTS connected together and arifing one from another. BY THE Right^Rev. Dr. GEORGE BERKELEY, Lord Bifhop of C L o Y N E, And Author of The Minute Philofcpber. As "we have opportunity, let us do good unto all men. Gal. vi. I o. Hoc opusy hocjludiurriy parvi proper emus et ampli. Hor. -A NEW EDITION, With ADDITIONS and EMENDATIONS. DUBLIN Printed, LONDON Re-printed, For W. INNYS, and C. HITCH, in Pater-nofter -rciv* and C. DAVIS in Holbourn. MDCCXLVU. [Price Two Shillings.] A Letter to T. P. Efq. frm tie Aatbor of SIR is. AMONG the great numbers who drink Tar-water in Dublin, your Better informs me there are feveral, that make it too weak or ten f-rongj rr ufe it in an undue manner. To ob- viate thffe inconveniences, and render this water as generally ufeful as pofli- ble, yi;u defire I would draw up fome rules and remarks, in a fruall com- pafs ; which accordingly ] here kr.d you. K .-lAvegijn tar Being theTnoft liquid, mrxerh beft with water. Put* gal- lon of told water to a quart of this tar, ftir and work them very fhongly to- gether, with a flat ftick, for about four minutes. Let the veflel (land cover- ed forty eight houis, that the tar may fubfxle. Then pour off the clear wa- ter, and keep it clofe covered, or rather bottled, and well flopped, for ufe. This rn.iy do for a general rule ; but as ftomachs and conftitutions are fo vari- ous, for particular petfons, their own experience is ttye beft'rule. The ftrong- er trie-better j provided the ftomach can bear it. Lefs v.-a*r or moreJtirring Makes it Wronger ; as more water, and lefs ftirring makes it weaker. The fame Jar will not do quite fo well a fecond time, but may ferve for common ufri. Tar-watar, when right, is not higher than French, nor deeper coloured, n Spani/h white wine. If there be not a fpirit very fenfibty perceived on \drinking, you may conclude, the tar water is not good. If you wouidlave "it good, fee it made yourfelf. Thofe who begin with it, little %nd weak, may, by habit, come to drrnk more and ftronger. According to the feafbu cl tfae'year, or the humour of the patient, it may be taken, cold or warmST- As to the quantity, in chronical cafes, one pint of tar-water a day may 'iWfrtce, taken on an empty ftomach, at two, or four times ; to wit, night and morning j and about two hours after dinner and.brcakfaft. 'AltentiTej, in gen ral, taken little and often, mix beft with the blood. How eft, or how ftrongj each ftomach can bear, experience will flew : nor is there any danger in making the experiment. Thofe who labour under old habitual ill- neffes, muft have great patience and perfeverance in the ufe of this, as well as 5n all other medicines ; which, if fureand fafe, rouft yet be flow in chronical diforder* \ which, if grievous or inveterate, may require a full quart every day to be taken, at fix dofes, one third of a pint in each, with a regular diet. In acute cafes, as fevers, of all kinds, it mujft be diank warm in bed, and in great quantity } perhaps a pint every hour, till the patient be relieved ; which I have known to wurk furprizing cures. My experiments have indeed been made within a narrow compafs 5 but as this water is now grown into publick ufe (though it feems not without that oppi>"t'on which is wont to attend novelty) 1 make no doubt, 5ts virtues will be ir<>re fully Jifcovtrcd. Mean while, I muft own myfelf perfuaded, from what I have already feen and tryed, that tar water may be drink with great fafety and fuccefs, ::; the cure or r-lief of mrft if not all dileafes, in ulcers, eruption*, and .n]l foul cafes ; fcurvlescf all kinds, diforders of the lungi, fto- jnach, and bowels ; in nervous c^frs, in all inflammatory diftempers j in de- cays, ard othtr maladies : Nor is it of ufe only in the cure of ficknefs ; it is alfoufcd to prcferve health, and a guard againft infection and old age; as it gives lading fpirts, and invipcrates the blood. I am even induced, by the na- ture and analogy of things, and its wonderful fuccefc in all kind: of fcvcrs f to think, that tar water may be very uftfiil in the plague, both as a cure and pre- fervative. But, I doubt no medicine can withftand that execrable plrgue of diftilled fpirits, which operate as a flow poifon, preying oh the vitals, aad waftingthe health and ftrcngth of the body and foul ; which, peft of human kird, is, 'I am told, by the attempts of our * Whifky patriots, gaining ground in this wretched country, already too thin of inhabitants. I am, &c. * Whilky '* * fpirit dijlilled from malt, tbi making of -which po'ifon, cheap atd fferty, ai Itir.g efnr frfivtkf it eftfemcd, ijjtmc unluckj patriots, a benefit tt itfir autttrj. C T J? T ^ % O / /V 1 ^3 * 0?>^ A CHAIN of PHILOSOPHICAL REFLEXIONS AND INQUIRIES, FOR INTRODUCTION to the following piece I afiure the reader, that nothing could, in my prefent fituation, have in- duced me to be at the pains of writing it, but a firm belief that it would prove a valua- ble prefent to the public. What entertainment fo- ever the reafbning or notional part may afford the mind, I will venture to fay, the other part feemeth fo furely calculated to do good to the body, chat both muft be gainers. For if the lute be not well tuned, the mufician fails of his harmony. And in our prefent ftate, the operations of the mind, fo far depend on the, right tone or good condition of it/s iriftrumenr, that any thing which greatly con- tributes to prefer-ve or recover the health of the body, is well worth the attention of the 'mind. Thefe confiderations have moved me to communi- cate to the public the falucary virtues of tar- wa- ter j to which I thought myfelf indifpenfably obliged, by the duty every man owes to mankind. And, as effects are Jinked with their caufcs,. my thoughts on this low, but ufeful theme, led to far- ther inquiries, and thofe on to others j remote per- haps, and fpeculadve, but r J hope, not altogether nffIf>fc nr nnfntfrfQininrr or unentertaming. A 2 (4) j. TN certain parts of America, tar- water is made by putting a quart of cold water to a quart of tar, and ft ii ring them well together in a veffel, which is left (landing till the tar finks to the bottom. A glais of clear water being poured off for a draught is replaced by the fame quantity of frcm water, the vefTcl being fhaken and left to ftanci as before. And this is repeated for every glafs, fo Jong as the tar continues to impregnate the water fufficientjy, which will appear by the frneJl and tafle. But as this method produceth tar- water of different degrees of ftrength, I chufe to make it in the following manner : Pour a gallon of cold water on a quart of tar, and ftir and mix them thoroughly with a ladle or flat flick for the fpace of three or four minutes, after which the vef- fel mufl fland eight and forty hours that the tar rnay have time to fubftde, when the clear water is to be poured off and kept covered for ufe, no more being made from the fame tar, which may ftilJ ferve for common purpofes. 2. The cold infufion of tar hath been ufed in fome of our colonies, as a prefervative or prepara- tive againfl the fmall-pox, which foieign practice induced me to try it in my own neighbourhood, when the fmall-pox raged with great violence. And the trial fully anfwered my expectation : all thofe, within my knowledge, who took the tar-water, having either efcaped that diftemper, or had it very favourably. In one family there was a re- markable inflance of feven children, who came ail very well through the fmall-pox, except one young child which could not be brought to drink tar- water as the reft had done. 3. Several were preferved from taking the fmall- by the ufe of this liquor : others had it in the mildeft ( 5) mildefr. manner, and others, that they might be able to take the infection, Were obliged to intermit .drinking the tar-water. I have found it may be drunk with great fafety and iiiccefs for any length cf time, and this not only before, but alfo during the diftemper. The general rule for taking it is, about half a pint night and morning on an empty ftomach, which quantity may be varied,- according to the cafe and age of the patient, provided it be always taken on an empty ftomach, and about two hours before or after a meal. For children and fqueamiih perfons it may be made weaker, and given little and often. More cold water, or lefs ftirring, makes it weaker ; as lefs Water, or more ftirring, makes it ftronger. It mould not be light- er than French, nor deeper coloured than Spanifh white wine. If a fpirit be not very feniibly per- ceiv'd on drinking, either the tar mult have been bad, or already us'cl, or the tar- water carelefsly made. - 4. It feemed probable, that a medicine of fuch efficacy in a diftemper attended with fo many pu- rulent ulcers, might be alfo ufeful in other fouf- nerTes of the blood ; accordingly I tried it on feve 7 ral perfons infected with cutaneous eruptions and ulcers, who were foon relieved, and foon after cu- red. Encouraged by thefe fuccefles I ventured to advife it in the foulcft diftempers, wherein it proved much more fuccefsful than falivations and wood-drinks had done. 5. Having tried it in a great variety of cafes, I found it fucceed beyond my hopes -, in a tedious and painful ulceration of the bowels, in a conlump- tive cough and (as appeared by expectorated pus) an ulcer in the lungs ; in a pleurify and peripeumony. And when a perfon, who for fome years had beerr fubje air impregnates vapour j and this becomes a watery juice by diftil- Jation, having rifen firft in the cold ftiil with a kindly gentle heat. This fragrant vegetable water is pofleflfed of the fpecific odour and tafte of the plant. It is remarked, that diftilled oils added to water for counterfeiting the vegetable water, can never equal it, artificial chemiftry falling mort of the natural. 46. The lefs violence is ufed to nature the bet- ter its produce. The juice of olives or grapes if- fuing by the lighteft preffure is beft, Refins that drop from the branches fpontaneoufly, or ooze upon the {lighteft incifion, are the fineft and moft (*) -3 7-43- fragrant. ( 23 ) fragrant. And infufions are obferved to aft more ftrongly than decoctions of plants, the more fub- tile and volatile fairs and fpirits, which might be loft or corrupted by the latter, being obtained in, their natural ftate by- the former. It is alfo obferv- ed, that the fined, pureft, and moft volatile part is that which firft afcends in diflillation. And, indeed; it mould feem the lighted and moft active particles required lead force to difengage them from the fubject. 47. The fairs, therefore, and more active fpirits of the tar are got by infufion in cold water : but the refinous part is not to .be diffolved there- by (a}. Hence the prejudice which fome perhaps may entertain againft Tar-water, as a medicine, the ufe whereof might inflame the blood by its ful- phur and refm, appears to be not well grounded; it being indeed impregnated with a fine acid fpi- rit, balfamic, cooling, diuretic, and poffefled of many other virtues (b). Spirits are fuppofed to confift of falts and phlegm, probably too fome- what of a fine oily nature, differing from oil in that it mixeth with water, and agreeing with oil, in that it runneth in rivulets by diftillation. Thus much is allowed, that the water, earth, and fixed fait are the fame in all plants : that, therefore, which differenceth a plant or makes it what, it is, the native fpark or form, in the language of the chemifts or fchools, is none of thofe things, nor yet the fineft oil, which feemeth only its recep- tacle or vehicle. It is obferved by chemifts, that all forts of balfamic wood afford an acid fpirit, which is the volatile oily fait of the vegetable : Herein are chiefly contained their medicinal virtues, and by the trials I have made, it appears, that the (a] Sea. 7. (*) Sea, 42, 44, ( 24 ) acid fpirit in tar-water pofiefieth the virtues, in an eminent degree, of that of guaiacum, and other medicinal woods. 48. Qualities in a degree too ftrong for human nature to fubdue, and affimilate to itfelf, mud hurt the conftitution. All acids, therefore, may not be ufeful or innocent. But this feemeth an acid fo thoroughly concocted, fo gentle, bland, and temperate, and withal a fpirit fo fine and volatile, as readily to enter the fmallefl veffels, and be alTi- milated with the utmoft eafe. 49. If any one were minded to difiblve fome of the refin, together with the fait or fpirit, he need only mix fome fpirit of wine with the water. But fuch an intire folution of refins and gums, as to qualify them for entering and pervading the animal fyflem, like the fine acid fpirit that firft flies off from the fubjecl, is perhaps impoffible to obtain. It is an apophthegm or the chemifts, deriv- ed from Helmont, that -whoever can make myrrh fbluble by the human body, has the fecret of pro- longing his days: and Boerhaave owns that there feems to be truth in this, from its refifting putre- faction. Now this quality is as remarkable in tar, with which the ancients embalmed and preferred dead bodies. And though Boerhaave himfelf, and other chemifts before him, have given methods for making folutions of myrrh, yet it is by means of alcohol, which extracts only the inflammable parts. And it doth not feem that any folution of myrrh is impregnated with its fait or acid fpi- rit. It may not, therefore, feem ftrange if this water mould be found more beneficial for procur- ing health and long life, than any folution of myrrh whatfoever. 50. Certainly divers refins and gums may have virtues, and yet not be able for their grofTnefs to pafs (25) pafs the lacteals and other finer veficls, nor yet, perhaps, readily impart thofe virtues to a men- itruum, that may with fafety and fpeed convey them throughout the human body. Upon all which accounts, -I believe tar- water will be found to have fingular advantages. It is obferved that acid fpirits prove the ftronger, by how much the greater degree of heat is required to raife them. And indeed, there feemeth to be no acid more gentle than this, obtained by the fimple affufion of cold water ; which carries off from the fubject the mod light and fubtile parts, and, if one may fo fpeak, the very flower of it's fpecific qualities. And here it is to be noted, that the volatile fait and fpirit of vegetables do, by gently ftimulating the folids, attenuate the fluids contained in them, and promote fecretions, and that they are pene- trating and active, contrary to the general nature of other acids. 51. It is a great maxim for health, that the juices of the body be kept fluid in a due propor- tion. Therefore, the acid volatile Ipirit in tar* water, at once attenuating and cooling in a mode- rate degree, mud greatly conduce to health, as a mild lalutary deobftruent, quickening the circula- tion of the fluids without wounding the folids, thereby gently removing or preventing thofe ob- ftructions, which are the great and general caufe of mod chronical difeaies j in this manner anfwer- ing to the antihyfterics, afla fcetida, galbanum, myrrh, amber, and, in general, to all the refins and gums of trees or fhrubs ufeful in nervous, cafes. 52. Warm water is it felf a deobftruent. There- fore the infufion of tar drunk warm, is eafier infi* nuated into all the nice capillary veflels, and acts not only by virtue of the baifam, bu; alfo by that D of (26) of the vehicle. It's tafte, it's diuretic quality, it's being fo great a cordial, fhew the activity of this medicine. And at the fame time that it quickens the fluggifh blood of the hyfterical, it's balfamic oily nature abates the too rapid motion of the fharp thin blood in thofe who are hectic. There is a Jentour and fmoothnefs in the blood of healthy flrong people ; on the contrary, there is often an acrimony and .folution in that of weakly morbid perfons. The fine particles of tar are not only warm and active, they are alib balfamic and emol- lient, foftening and enriching the fharp and vapid blood, and healing the erofions occafioned thereby in the blood-vefiels and glands. 53. Tar- water poffcffeth the ftomachic and car- diac qualities of Elixir proprietatis, Stoughton's drops, and many fuch tinctures and extracts, with this difference, that it worketh it's effect more fafely, as it hath nothing of that fpirit of wine, which, however mixed and difguifed, may yet be well accounted a poifon in fome degree. 54. Such medicines are fuppoicd to be diapho- retic, which, being of an active and fubtile nature, pafs through the whole fyflem, and work their effect in the fined capillaries and perfpiratory ductSj which they gently cleanfe and open. Tar- water is extremely well fitted to work by fuch an infenfible diaphorefis, by the finenefs and activity of it's acid volatile fpirit. And furely thofe parts ought to be very fine, which can fcour the per- fpiratory ducts, under the fcarf fkin or cuticle, if it be true that one grain of fand would co- ver the mouths of more than a hundred thou- fand. 55. Another way wherein tar-water operates, is by urine, than which perhaps none is more fafe and effectual, for cleaning die blood and carrying off off it's fa/ts. But it feems to produce it's princi- pal effect as an alterative, fure and eafy, much lafer than thofe vehement purgative, emetic, and falivating medicines, which do violence to nature. 56. An obftruction of fome veflels caufeth the blood to move more fwiftly in other veffeis, which are not obftructed. Hence manifold diforders. A Jiquor that dilutes and attenuates, refolves the con- cretions which obftruct. Tar-water is fuch a li- quor. It may.be faid, indeed, of common water, that it attenuates, alfo of mercurial preparations that they attenuate. But it mould be con fide red that mere water only diftends the veflels and there- by weakens their tone , and that mercury, by it's great momentum, may juftly be fufpected of hurt* ing the fine capillaries, which two deobftruents therefore might eafily over-act their parts, and (by leflening the force of the elaftic vellels) remotely produce thofe concretions they are intended to re- move. 57. Weak and rigid fibres are looked on by the moft able phyficians, as fources of two differ- ent clafles.of dittempers : a flnggifli motion of the liquids occafions weak fibres : therefore tar- water is good to ftrengthen them as it gently accelerates their contents. On the other hand, being an un- ctuous bland fluid, it moiftens and foftens the dry and ftiff fibres : and fo proves a remedy for both extremes. 58. Common foaps are compofitions of lixivial fait and oil. The corrofive acrimony of the fa- line particles being foftened by the mixture of an unctuous fubftance they infinuate themfelves into the fmall ducts with lefs difficulty and danger. The combination of thefe different fubftances makes up a very fubtile and active medicine, fit- ted for mixing with all humours, and refolving D 2 all ( 28 ) all obftructions. Soap therefore is juftly eileemed a moft efficacious medicine in many diftempers. Alcaline foap is allowed to be cleanfing, attenuat- ing, opening, refolving, fweetening ; it is pectoral, vulnerary, diuretic, and hath other good qualities, which are alfo to be found in tar-water. . It is granted, that oil and acid falts combined together exiit in vegetables, and that confequently there are acid foaps as well as alcaline. And the fapona- ceous nature of the acid vegetable fpirits, is what renders them fo diuretic, fudorific, penetrating, abflerfive and refolving. Such, for inftance, is the acid fpirit of Guaiacum. And all thefe fame virtues feem to be in tar- water in a mild and falutary degree. 59. It is the general opinion that all acids coa- gulate the blood. Boerhaave excepts vinegar, which he holds to be a foap, inafmuch as it is found to contain an oil as well as an acid fpirit. Hence it is both unctuous and penetrating, a powerful anti- phlogiftic, and prefervative againft corruption and infection. Now it feems evident that tar-water is a foap as well as vinegar, For though it be the character of refin, which is an infpiflated grofs oil, not to difiblve in water (#), yet the falts at- tract fome fine particles of effential oil : which fine oil ferves as a vehicle for the acid falts, and mews itfelf in the colour of the tar-water 5 for all pure falts are colourlefs. And though the refin will not diffo've in water, yet the fubtilc oil, in which the vegetable falts are lodged, may as well mijf with water as vincs;ar doth, which contains both O oil and fait. And as the oil in tar-water difcovers M to the eye, fo the acid falts do rnanifeil (} Seft. . ( 29) themfelves to the tafte. Tar-water therefore is a foap, and as fuch hath the medicinal qualities of foaps. 60. It operates more gently as the acid falts lofe their acrimony being fheathed in oil, and thereby approaching the nature of neutral falts, are more benign and friendly to the animal fy- ilem : and more effectually, as, by the help of a vo- latile fmooth infinuating oil, thofe fame falts are more eafily introduced into the capillary ducts. Therefore in fevers and epidemical djftempers it is (and I have found it fo) as well as in chroni- cal difeafes, a mofl fafe and efficacious medicine, being good againft too great fluidity as a balfa- mic, and good againft vifcidity as a foap. There is fomething in the fiery corrofive nature of lixi- vial falts, which makes alcaline foap a dangerous remedy in all cafes where an inflammation is appre- hended. And as inflammations are often occailoned by obftructions, it mould feem an acid foap was much the fafer deobftruertf. 61. Even the beft turpentines, however famous for their vulnerary and detergent qualities, have yet been obferved by their warmth to difpofe to inflammatory tumours. But the acid fpirit (a) being in fo great proportion in tar-water renders it a cooler and fafer medicine. And the jetherial oil of turpentine, though an admirable drier, healer, and anodyne, when outwardly applied to wounds and ulcers, and not lefs ufcful in cleanfing the urinary paffages and healing their ulcerations, yet is known to be of a nature fo very relaxing as fometimes to do much mifchief, when taken inwardly. Tar-water is not attended with the fame ill effects, which I Relieve are owing in a great meafure to the astherial () Sea 7, S. oil's (30 ) oil's being deprived of the acid fpirit in diftillation, which vellicating and contracting as a flimulus might have proved a counterpoife to the exceflive lubricating and relaxing qualities of the oil. 62. Woods in decoction do not feem to yield fo ripe and elaborate a juice, as that which is depo- iited in the cells or loculi terebinthiaci, and fpon- taneoufly oozes from them. And indeed though the balfam of Peru, obtained by boiling wood and fcumming the deception, be a very valuable medi- cine and of great account in divers cafes, particu- larly afthmas, nephritic pains, nervous colics, and obftructions, yet I do verily think (and I do not fay this without experience) that tar- water is a more efficacious remedy in all thofe cafes than even that coftly drug. 63. It hath been already obferved, that therefto- rative pectoral antihyfterical virtues of the mbft pre- cious balfams and gums are poflefled in a high de- gree by tar-water (a). And I do not know any purpofe anfwered by the wood drinks, for whicn tar-water may not be ufed with at leaft equal fuc- cefs. It contains the virtues even of Guaiacum which feems the moft efficacious of all the woods, warming and fweetening the humours, diaphoretic and uieful in gouts, dropfies and rheums, as well as in the foul difeafe. Nor mould it feem ftrange, if the virtues obtained by boiling an old dry wood prove inferior to thofe extracted from a balfam. 64. There is a fine volatile fpirit in the waters of Geronfter, the moft efteemed of all the fountains about Spa, but whofe waters do not bear tranfport- ing. The ftomachic, cardiac, and diuretic qualities of this fountain fomewhat re-fern ble thofe of tar- water, which, if I am not greatly miftaken, con- fwer of do- ing good above other deobftruents, doth alfo dif- pofe it to do mifchief. I mean it's great momentum, the weight of it being about ten times that of blood, and the momentum being the joint pro- duct of the weight and velocity, it mutt needs operate with great force ; and may it not be juftly feared, that fo great a force entering the minutett E velll-ls, ( 34 ) veffcls, and breaking the obftructed matter, might alfo break or wound the fine tender coats of thofe fmall veflels, and fo bring on the untimely effects of old age, producing more perhaps, and worfe obftructions than thofe it removed ? Similar confe- quences may juftly be apprehended from other mi- neral and ponderous medicines. Therefore upon the whole, there will not perhaps be found any medicine, more general in it's life, or more falu- tary in it's effects than tar- water. 72. To fuppofe that all diftempers arifing from very different, and, it may be, from contrary caufes, can be cured by one and the fame medi- cine, muft feem chimerical. But it may with truth be affirmed, that the virtue of tar- water extends to a furprizing variety of cafes very diftant and un- like (a). This I have experienced in my neigh- bours, my family, and myfelf. And as I live in a remote corner among poor neighbours, who for want of a regular phyfician have often recourfe to me, I have had frequent opportunities of trial, \vhich convince me it is of fo juft a temperament as to be an enemy to all extremes. I have known it do great good in a cold watery conftitution, as a cardiac and flomachic ; and at the fame time allay heat and feverifh thirft in another. I have known it correct coftive habits in fome, and the contrary habit in others. Nor will this feem incredible, if it be confidered that middle qualities naturally re- duce the extreme. Warm water, for inftanee, mixed with hot and cold will leflen the heat in that, and the cold in this. 73. They who know the great virtues of com- mon foap, whofe coarfe lixivial falts are the pro- (*;Sett. 3, 4,5,6, 21. fc?< duct (35) duct of culinary fire, will not think it incredible that virtues of mighty force and extent fhould be found in a fine acid foap (ut not with water, Sir ( 54 ) ii3- Sir John Floyer remarks, that we want a method for the ufe of turpentine, and again, he who fhall hit, faith he, on the pleafanteft method of giving turpentine, will do great cures in the gout, ftone, catarrhs, dropfies, and cold fcurvies, rheu- matifms, ulcers, and obftrudtlons of the glands. Laftly, he fubjoins, that for the ufe of altering and amending the juices and fibres, it muft be given frequently, and in fuch fmall quantities at a time, and in fo commodious a manner, as will agree beft with the flomach (#), ftay Jongeft in the body, and not purge itfelf off , for large doles (faith he) go through too quick, and befides offend the head. Now the infufion of tar or turpentine in cold wa- ter feems to fupply the very method that was wanted, as it leaves the more unctuous and grofs parts behind (), which might offend the flomach, inteftines, and head ; and as it may beeafily taken, and as often, and in fuch quantity, and fuch degree of ftrength, as fuits the cafe of the patient. Nor mould it feem, that the fine fpirit and volatile oil, obtained by infufion of tar (c) is inferior to .that of turpentine-, to which it fuperadds the virtue of wood foot, which is known to be very great with refpect to the head and nerves ; and this ap- pears evident from the manner of obtaining tar (d}. And as the fine volatile parts of tar or tur- pentine are drawn off by infufion in cold water and eafily conveyed throughout the whole fyftem of the human body i fo it mould feem the fame me- thod may be ufed with all forts of balfams or refins whatfoever, as the readied, eafieft, and mod in- offenfive, as well as in many cafes the moil effectual way of obtaining and imparting their virtues. '( a ) 9. (1} 47. (c} 7l 2> 5& (^,13- 114, After 1 (55) 1 14. After having faid fo much of the ufes of tar, I muft farther add, that being rubb'd on them it is an excellent prefervative of the teeth and gurns ; that it fweetens the breath, and that it clears and ftrengthens the voice. And, as its effects are va- rious and ufeful, fo there is nothing to be feared from the operation of an alterative fo mild and friendly to nature. It was a wife maxim of certain ancient philofophers, that difeafes ought not to be irritated by medicines. But no medicine di- flurbs the animal ceconomy lefs than this (a), which, if I may truft my own experience, never produces any diforder in a patient when rightly taken. 115. I knew indeed a perfon who took a large glafs of tar- water juft before breakfail, which gave him an invincible naufea and difguft, although he had before received the greateft benefit from it. But if the tar-water be taken and made in the man- ner prefcribed at the beginning of this efTay, it will, if I miftake not, have enough of the fait to be ufe- ful, and little enough'' of the oil to be inoffenfive. I mean my own manner of making it, and not the American ; that fometimes makes it too ftrong, and fometimes too weak ; which tar-water, how- ever it might ferve as there ufed, merely for a pre- parative againft the fmall-pox, yet I queftion whe- ther it may be fitly ufed in all thofe various cafes wherein I have found tar-water fo fuccefsful. Per- fons more delicate than, ordinary may render it palatable, -by mixing a drop of the chemical oil of nutmegs, or a fpoonful of mountain wine in each glals. It may not be amifs to obferve, that I have known fome, whofe nice ftomachs could not bear it in the morning, take it at night going to bed without any inconvenience -, and that with fome it agrees beft warm, with others cold. It may be W-33- made made Wronger for brute beads, as horfes, in whofe diforders I have found it very ufeful, I believe more ib than that bituminous fubftance call'd Barbadoes far. li 6. In very dangerous and acute cafes much may be taken and often ; as far as the ftomach can bear. But in chronical cafes, about half a pint, night and morning, may fuffice ; or in cafe ib large a dofe mould prove difagreeablej half the quantity may be taken at four times, to wit, in the morn- ing, at night going to bed, and about two hours after dinner and breakfaft. A medicine of fo great virtue in fo many different diforders, and efpecially in that grand enemy, the fever, muft heeds be a benefit to mankind in general. There arc neverthelefs three forts of people to whom I would- peculiarly recommend it : Sea-faring perfons, la- dies, and men of fludious and fedentary lives. 117. To failors and all fea- faring perfons, who are fubjecl: to fcorbutic diforders and putrid fevers, efpecially in long fouthern voyages, I am perfua- ded this tar-water would be very beneficial, And this may deferve particular notice in the prefent courfe of marine expeditions, when fo many of our country-men have perifhed by fuch diftempers, contracted at fea and in foreign climates. Which, it is probable, might have been prevented, by the copious ufe of tar- water. 11 8. This fame water will alfo give charitable relief to the ladies ( and the more fo, be- caufe my pains were exafperated by exercife. But fince the ufe of Tar- water, I find, though not a per- fect recovery from my old and rooted illnefs* yet fuch a gradual return of health and eafe, that I efteem my having taken this medicine the greateft of all temporal bleffings, and am convinced that, under Providence, I owe my life to it. 1 20. In the diftilling of turpentine and other balfams by a gentle heat, it hath been obferved, that there rifeth firft an acid fpirit (n), that will mix with water; which fpirit, except the fire bs very gentle, is loft. This grateful acid fpirit that firft comes oVer^ is, as a learned chemiffc and phyfician informs us, highly refrigeratory, diuretic, fudorific, ballamic or prefervative from putrefaction, excellent in nephritic cafes, and for quenching thirft, all which virtues are contained in the cold infufion, which draws forth from tar only its fine flower or quinteflfence, if I may fo fay, or the native vegetable fpirit, together with n. little volatile oil. 121. The diftinguiming principle of all vege- tables, that whereon their peculiar fmell, tatte, and fp?cific properties depend, feems to be fome (*) 7- extremely ( 58 ) extremely tine and fubtile fpirir, whofe immediate vehicle is an exceeding thin volatile oil, which is irfcJf detained in a grofTer and more vifcid re- Jin or ballam, lodged in proper cells in the bark and feeds, and moit abounding in autumn or win- ter, after the crude juices have been thoroughly concocted, ripened, and impregnated with fbla: light. The fpirit itfclf is by fome fuppofed to be an oil highly fubtilized, fo as to mix with water. But fuch volatile oil is not the fpirit, but only its vehicle. Since aromatic oils, be- ing long expofed to air, will Jofe their fpecific irnejl and tafte, which fly off with the fpirit or vegetable fait, without any fenfible diminution of the oil. 12,2. Thofe volatile falts, that are fct free and raifed by a gentle heat, may juftly be fuppofed eflential (a), and to have pre-exifted in the ve- getable; whereas the lixivial fixed falts obtained by the incineration of the fubjecl, whofe natural condiment parts have been altered or deftroyed by the extreme force of fire, are by later chemifts > Vipon very good grounds, fuppofed not to have pre-exifted therein;, all fuch falts appearing, from the experiments of fignor Recli, not to preferve the virtues of the refpeclive vegetable fubjects; and to be alike purgative and in an equal de- gree, whatfoever may be the fhape of their points, whether fharp or obtufe. But although fixed or Jixivious falts may not contain the original pro- perties of the fubjcct; yet volatile falts raifed by a flight heat from vegetables are allowed to preferve their native virtues : and fudi falts are readily im- bibed by water. 123. The mod volatile- of the falts, and the nloft attenuated part of the oil,- may be fuppofed (a)' 8. the ( 59 ) the firft and readiefl to impregnate a cold infu- fion (b). And this will afliit us to account for the virtues of tar-water. That volatile acid in vegetables, which refifts putrefaction, and is their great prefervative, is detained in a fubtile oil mif- cible with . \vater r which oil is itfelf impriibned in the refin or groflfer part of the tar, from which it is eafily fet free and obtained pure by cold wa- ter. 124. The mild native acids are obferved more kindly to work upon, and more thoroughly to ciifiblve, metallic bodies, than the fbrongeft acid (pints produced by a vehement fire; and it may be fufpected, they have the fame advantage as a medicine. And as no acid, by the obfcrvation of fome of the bed chemifts, can be obtained from the fubftahce of animals thoroughly affirm- kted, it fhould follow, that the acids received into a healthy body muft be quite fubdued and changed by the vital powers : but it is eafier to fub- due and afiimilate (c) the gentler than the Stronger acids. 125. I am very fenfible, that on fuch fubjech arguments fall fhort of evidence: and that mine fall fhort even of what they might have been, if I enjoyed better health, or thofe opportunities of a karned commerce, from which I am cut off in this remote corner. I fhall neverthelefs go on as I have begun, and proceed by reafon, by .con- jedure, and by authority, to caft the bed light. I can on the obfcure paths that lie in my way. 126. Sir I faac Newton, Boerhaavc, and Hoin- berg are all agreed, that the acid is a fine fubtile fubftance, pervading the whole terraqueous globe-, which produceth divers kinds of bodies, as it is united to different fubjecls. This, according to ' (1>) i, 7. ( c ) 4 8. H 2 Hamburg, ( 60 ) H'omberg, is the pure fait, fait the principle, in it felf fimilar and uniform, but never found alone. And although this principle be called the fait of the earth, yet it mould feem it may more pro- perly be called the fait of the air, fince earth turned up and lying fallow receives it from the air. And it fhould feem that this is the great principle of vegetation, derived into the earth 'from all forts of manures, as well as from the air. This acid is allowed to be the caufe of fer- iiientation in all fermented liquors. Why there- fore, may it not be fuppofed to ferment the earth, and to conftitute that fine penetrating principle, which introduces and affimilates the food of plants, und is fo fugitive as to efcape all the filtrations and perquifitions of the niofl nice obfervers? 127. It is the doctrine of Sir Ifaac Newton and Monfieur Homberg, that, as the watry acid js that which renders fait foluble in water, fo it is that fume which joined to the earthy part makes it a fait. Let it therefore be confidered, that the organs (d) of plants are tubes, the filling, un- folding, and diftending whereof by liquors, doth conflitute what is called the vegetation or growth vf "the plant. But "earth itfeif is not foluble in water, fo as to form one vegetable fluid there- with. Therefore the particles of earth muft be joined with a watry acid, that is, they muft be- come falts in order to difiblve in water; that ib, in the form of a vegetable juice, they may pals through the ftrainers and tubes of the root into : body of the plant, fv/elling and diftending parts and organs, that is, increafing its bulk. Therefore the vegetable matter of the earth is 'in teH earth changed into fair. And to render earth (<*) 3> 3 f > 35- fertile (61 ) fertile, is to eaufe many of its particles to aflame a feline form. 128. Hence it is obferved, there are more faks in the root than in the bark, more falts in vegetables during the fpring, than in the autumn or winter, the crude faline juices being in the iummer months partly evaporated, and partly ri- pened by the action and mixture of light. Hence alfo it appears, why the dividing of earth, fo as to enlarge its furface, whereby it may admit more acid from the air, is of fuch ufe in pro- moting vegetation : Arid why afhes, lime, and burnt clay are found fo profitable manures, fire being in reality the acid, as is proved in the le- quel (a). Marls alfo and fhells are ufeful, foral- much as thofe alkaline bodies attract the acid, and raife an effervescence with it, thereby promoting a fermentation in the glebe. The excrements of animals and putrid vegetables do in like manner contribute to vegetation, by increafing the falts of the earth. And where fallows are well broken, and lye long to receive the acid of the air into all their parts; this alone will be fufficient to change many terrene particles into falts, and confequently render them foluble in water; and therefore fit ali- ment for vegetables. 129. The acid, faith Homberg, is always join- ed to fome fulphur, which determines it to this or that fpecies, producing different falts, as it is the vegetable, bituminous, or metallic fulphur. fi- ve n the alkaline, whether volatile or lixivial falts, are fuppofed to be, nothing but this fame acid ftridly detained by oil and earth, in fpight of the extreme force of fire, which lodgeth in them, without being able to diflodge fome remains of the acid, (a) 202. $30. Salts, 1 30. Saits, according to Sir Ifaac Newton, are dry earth and watery acid united by attraction, the 'acid rendering them foluble in water (/). He fuppofeth the . watery acid to flow round the ter- reitrial part, as the ocean doth round the earth, being attracted thereby, and compares each par- ticle of fait, to a chaos whereof the innermoft part is hard and earthy, but the furface foft and watery. Whatever attracts and is attracted mod ftrongly is an acid in his fenfe. 131. It feems impofiible to determine the figures of particular falts. All acid folvents together with the diffolved bodies are apt to Ihoot into certain figures. And the figures, in which the foflil falts cryftallize, have been fuppofed the proper natural fnapes of them and their acids. But llomberg hath clearly mewed the contrary : forafmuch as the lame acid diilblving different bodies, affumes dif- ferent fhapes. Spirit of nitre, for inllance, hav- ing diflblved copper, Ihootsinto hexagonal cryrb. the fame having diffolved iron, moots into irregu- lar fquares; and again, having difiblved fii'vcr, forms thin cryilals of a triangular figure. 132. Homberg nevertheiefs holds in general, that acids are fbaped like daggers, and alcaiies like iheaths: and that moving in the fame liquor, die diggers run into the fbeaths fitted to receive them, with fuch violence as to raife that effervefcence ob- fervcd in the mixture of acids and alkalies. But it fcems very difficult to conceive, how, or why the mere configuration of daggers and iheaths, floating in the fame liquor, mould caufe the former to rufli with fuch vehemence, and direct their points ib aptly into the latter, any more than a parcel of fpir gots, and foffets floating together in. the fame water, :1roi:Id rufh one into the other. 133- It ( 63 ) 133- It fnoukl feem rather, that the vehement attraction which Sir Ifaac Newton attributes to all acids, whereby he fuppoieth them to ruLh towards, penetrate, make, and divide the mcft folid bodies, and to ferment the liquid of vegetables, could bet- ter account for this phenomenon. It is in this at- traction, that Sir Ifaac placeth all their activity, and indeed it fhould feem, the figures of falts were not of fuch efficacy in producing their effects, as the llrong attractive powers whereby they are agitated and do agitate other bodies. Efpecially if it be true (what was before remarked) that lixivious falts are alike purgative, whatever may be the lhape of their angles, whether more or Ids acute or obtufe. 134. Sir Ifaac Newton accounts for the water acids making earthy corpufcles foluble in water, by fuppoiing fhe acid to be a mean between earth and water, its particles greater than thole of wa- ter, and Jefs than thofe of earth, and ftrongly to attract both. But perhaps there is no neceiTary reaibn for fuppofing the parts of the acid groflet than the parts of water, in order to produce this . effect; may not this as well be accounted for, by giving them only a ftrong attraction or cohefion with the bodies to which they are joined ? 135. The acid fpirit or fait, that mighty inftru- ment in the hand of nature, refiding in the air, and. diffufed throughout that whole element, is difcer- niblealfo in many parts of the earth, particularly in foflils, fuch as fulphur, vitriol, and allum; it was already obferved from Romberg, that this acid is never found pure, but hath always fulphur joined with ir, and is ciafied by the difference of its fui- phurs, whether mineral, vegetable, or animal. 136. Salts are vulgarly reckoned the moft active- of chemical principles. But Hocnberg derives alf their ( 64) their activity from the fulphurs joined with them. From which alfo, as hath been faid, he derives all their kinds and differences QJ-). Salt, water, oil, and earth feem to be originally the fame in all ve- getables. All the difference, according to the chemifts, arifeth from a fpirit refiding in the oil, called the Redor or Archsus. This is otherwifc called by chemifts, ens primum, or the native fpi- rit, whereon depend, and wherein are contained, the peculiar flavour and odour, the ipecific quali- ties and virtues of the plant. 137. Thefe native Ipirits or vegetable fouls are all breathed or exhaled into the air, which feems the receptacle as well as Iburce of all fublunary forms, the great mafs or chaos which imparts and receives them. The air, or atmofphere, that fur- rounds our earth, contains a mixture of all the active volatile parts of the whole habitable world, that is, of all vegetables, minerals, and animals. Whatever perfpires, corrupts, or exhales, impregnates the air; which, being acled upon by the folar fire, produ- ceth within itfelf all forts of chemical operations, difpenfing again thofe falts and fpirits in .new generations, which it had received from putrefac- tions. 138. The perpetual ofcillations of this elailic and reftlefs element operate without ceafing on alJ things that have life, whether animal or vegetable, keeping their fibres, veffels, and fluids in a motion always changing-, as heat, cold, moifture, drynefs, and other caufes alter the elafticity of the air. Which accounts, it muft be owned, for many effecls. But there are many more which muft be derived from other principles or qualities in the air. Thus iron and copper are corroded and gather ruft in the air, and bodies of all forts are difiolved or corrupted, (s) 12 9- which which meweth an acid to abound and difTuie itfelf throughout the air. 139. By this fame air fire is kindled, the Limp of life prefcrved, refpiration, d : geftion, nutrition^ , the pulfe of the heart and motion of all the muf- cles feem to be performed. Air therefore is a ge- neral agent, not only exerting its own, but calling forth the qualities or powers of rJl other bodies, b^ a divificn, comminution, and agitation of their particles, caufing them to fly off and become vo- latile and aclive. 140. Nothing ferments, vegetates, or putrefies without air, which operates \vith all the virtu s of the bodies included in it; that fc> cfall nature; there being no drug, falutary or poifonous", whofe virtues are not breathed into the air. The airthefe'- fbre is aruictive mafs of numberlefs different prin- ciples, the general fource of corruption and gen'e- ratfioni on- one hand dividing, abrading, and car- rying off the particles of bodies, that is, corrupt- ing or diflblving them ; on the other, producing new ones into being', dcfbroyrng and beftowing forms wirhout intermiflion. 14 r. The feeds of things feem to lye latent in the air, ready to appear and produce their kind, whenever they light on a proper matrix. The ex- tremely fmall feeds of fern, mofle^ muftirooms, and fome other plants are concealed and wafted a- bout rn the air, every part - whereof fccms rcpL te with feeds of one kind or other. The whole' at- mofpHere feems alive. There is* every where acid ro corrode, and ft-cd to engender. Iron will rtifr, and mold wHl grow in ail places. Virgin earth be- comes fertile, crops of new phnts evtr and anon ihew themfelves; all which demonstrates the' air to- be a common feminary and reccpcablc" of air vivi-' fying principles. I 142, Air (66) 142. Air may alfo be faid to be the feminary of minerals and metals, as it is of vegetables. Mr. Boyle informs us, that the exhaufted ores of tin and iron being expofed to the air become again im- pregnated with metal, and that ore of alum having loft its fait recovers it after the fame manner. And numberlefs inftances there are of falts produced by the air, that vaft collection or treafury of active principles, from which all fublunary bodies feem to derive their forms, and on which animals depend for their life and breath. 143. That there is fome latent vivifying fpirit difperfed throughout the air, common experience fheweth j inafmuch as it is neceffary both to vege- tables and animals (b) whether terreftrial or aquatic, neither beafls, infects, birds, nor fifties being able to fubfift without air. Nor doth all air fuffice, there being fome quality or ingredient, of which when air is deprived, it becometh unfit to main- tain either life or flame. And this even though the air mould retain its elafticity ; which, by the bye, is an argument that air doth not act only as an an- tagonift to the intercoital mufcles. It hath both that and many other ufes. It gives and preferves a proper tone to the veflels: this elaftic fluid pro- motes, all fecretions: its ofcillations keep every part in motion : it pervades and actuates the whole ani- mal fyilem, producing great variety of effects, and even oppofite in different parts, cooling at the fame time and heating, diftending and contracting, co- agulating and refolving, giving and taking, fuf- taining life and impairing it, prefling without and expanding within, abrading fome parts, at the fame time infinuating and fupplying others, pro- ducing various vibrations in the fibres, and fer- (b) 138, 139. ments (67) ments in the fluids ; all which mufl needs enfue from fuch a fubtile, active, heterogeneous and elaflic fluid. 144. But there is, as we have obferved, fome one quality or ingredient in the air, on which life more immediately and principally depends. What that is, though men are not agreed, yet it is agreed that it mufl be the fame thing that fupports the vital and the common flame ; it being found that when air, by often breathing in it, is become unfit for the one, it will no longer ferve for the other. The like is obferveable in poifonous damps or fleams, wherein flame cannot be kindled. As is evident in the Grotto del cane near Naples. And here it oc- curs, to recommend the plunging them into cold water, as ah experiment to be tried on perfons af- fected by breathing a poifonous vapour in old vaults, mines, deep holes or cavities under ground. Which, I am apt to think, might fave the lives of feveral, by what I have fcen pra^lifed on a dog convulfed, and in all appearance dead, but inflantly reviving on being taken out of the abovementioned grotto and thrown into a lake adjacent. 145. Air, the general menftruum and feminary, feemeth to be only an aggregate of the volatile parts of all natural beings, which varioufly combined and agitated produce many various effects. Small particles in a near and clofe fituation ftrongly aft upon each other, attracting, repelling, vibrating. Hence divers fermentations, and all the variety of meteors, tempefls, and concuflions both of earth and firmament. Nor is the microcofm lefs affected thereby. Being pent up in the vifcera, veffels, and membranes of the body, by its falts, fulphurs, and elaftic power, it engenders colics, fpafmsj hyileric diforders, and other maladies. 16. The fpecific quality of air is taken to be 1 ? permanent (68 ) permanent elafticity. Mr. Boyle is exprefsly of this opinion. And yet, whether there be any fuch thing as permanently elaftic air may be doubted, there being many things which feem to rob .the air of" this quality, or pt lead kflen and fufpend its exertion. The falls and fulphurs, for inflance, that float in the air abate much of its elafticity by their attraction. 147. Upon the whole it is manifeft, that air is no diitinct clement, but a mafs or mixture of things the moft heterogeneous and even oppofite to each other (?), which become air, by acquiring an elafticity and volatility from the attraction of fome active, fubtile fubftance; whether it be called fire, Aether, light, or the vital fpirit of the world ; in like manner as the particles of antimony, of them- .felves not volatile, are carried off in fublimation and rendered volatile, by cohering with the par- ticles of fal ammoniac. But action and reaction being equal, the fpring of this ethereal fpirit is diminifbed by being imparted. Its velocity and fubtilty are alfo lefs from its being mixed with groiTer particles. Hence found moves flower than light, as mud than water. 148. Whether air be only freed and fixed, or generated and destroyed, it is certain that air begins and ceafes to exert and fhew itfelf. Much by expe- riments feems to be generated, not only from ani- mals, fruits, and vegetables, but alfo from hard bodies. And it is obferved by Sir Ifaac Newton, that air produced from hard bodies is moft elaftic. The tranfmutation' of elements, each into other, ba'-h been anciently held. In Plutarch we find it \vasthe opinion of Heraclitus, that the death of fire \v:s a birth to air, and the death of air a birth to \vatcr. This opinion is alio maintained by fJ'37 H5- Sl f ( 69 ) Sir Ifaac Newton. Though it may be queftioned, whether what is thought a change be not only a difguife. 149. Fire feems the moft elaftic and expanfive of all bodies. It communicates this quality to moid vapours and dry exhalations, when it heats and a- gitates their parts, cohering clofely with them, overcoming their former mutual attraction, and caufing them, inftead thereof, reciprocally to re- pel each other and fly afunder, with a force pro- portionable to that wherewith they had cohered. 150. Therefore in air we may conceive two parts, the one more grofs, which was raifed and carried off from the bodies of this terraqueous mafs: the pther a fine fubtile fpiritby means where- of the former is rendered volatile and elaftic. Together they compofe a medium, whofe elaiticity is lefs than that of pure aether, fire, or fpirit, in proportion to the quantity of falts, vapours, and heterogeneous particles contained therein. Hence it follows, that there is no fuch thing as a pure fim- ple element of air. It follows alfo, that on the high- eft mountains air mould be more rare than in pro- portion to the vulgar rule, of the fpaces being re- ciprocally as the preffures : and fo in fact it is faid to have been found, by the gentlemen of the French Academy of Sciences. 151. .Ether, fire, or fpirit being attracted and clogged by heterogeneous particles becometh lefs active; and the particles cohering with thofe of aether, become more active than before. Air there- fore is a mafs of various particles, abraded and fub- limated from wet and dry bodies of all forts, co- hering with particles of aether ; the whole per- meated by pure aether, or light, or fire: for thefe words are ufed promifcuoufly by ancient philofo- TS. 152. This php ( 7) 152. This asther or pure invifible fire, the molt fubtile and elaftic of all bodies, feems to pervade and expand itfelf throughout the whole univerfe. If air be the immediate agent or inftru- ment in natural things, it is the pure invifible fire that is the firft natural mover or fpring, frotn whence the air derives its power (#). This migh- ty agent is every where at hand, ready to break forth into action, if not reftrained and governed with the greateft wifdom. Being always refhlefs and in motion, it actuates and enlivens the whole vifible mafs, is equally fitted to produce and to deftroy, diftinguifhes the various ftages of nature, and keeps up the perpetual round of generations and corruptions, pregnant with forms which it conftantly fends forth and reforbs. So quick in its motions, fo fubtile and penetrating in its na- ture, fo extenfive in its effects, it feemeth no o- ther than the vegetative foul or vital fpirit of the world. 153. The animal fpirit in man is the inftru- mental or phyfical caule both of fenfc and mo- tion. To fuppofe fenfe in the world, would be grofs and unwarranted. But loco-motive faculties are evident in all its parts. The Pythagoreans, Platonifts, and Stoics held the world to be an ani- mal. Though fome of them have chofen to con- fidcr it as a vegetable. However the phenomena and effects do plainly mew there is a fpirit that moves, and a mind or providence that prefides. This providence, Plutarch faith, was thought to be in regard to the world, what the foul is jo re- gard to man. 154. The order and courfe of things, and the experiments we daily make, mew there is, a mind that governs and actuates this mundane fyftem, (a) 139, 149, 1 5 1. as ( 7' ) as the proper real agent and caufe. And that the inferior inftrumental caufe is pure ^ther, fire, or the fubfhnce of light (V) which is applied and de- termined by an infinite mind in the microcofm or univerfe, with unlimited power, and according to ftated rules j as it is in the microcofm, with limited power and fkill by the human mind. We have no proof either from experiment or reafon, of any other agent or efficient caufe than mind or fpirit. When therefore we fpeak of cor- poreal agents or corporeal caufes, this is to be under- ilood in a different, fubordinate, and improper fenfe. 155. The principles whereof a thing is com- pounded, the inftrument ufed in its production, and the end for which it was intended, are all in vulgar ufe termed Caufes, though none of them be flriclly fpeaking agent or efficient. There is not any proof that an extended corporeal or mecha- nical caufe doth really and properly act, even mo- tion itfelf being in truth a paffion. Therefore though we fpeak of this fiery fubftance as acting, yet it is to be underftood only as a mean or in- ftrument, which indeed is the cafe of all mecha- nical caojfes whatfoever. They are neverthelefs fometimes termed agents and caufes, although they are by no means active in a ftrict and proper fig- nification. When, therefore, force, power, vir- tue, or action are mentioned as fubfilling in an extended and corporeal or mechanical being, this is not to be taken in a true, genuine, and real, but only in a grofs and popular fenfe, which flicks in appearances, and doth not analyfe things to their firft principles. In compliance with efta- blifhed language, and the ufe of the world, we muft employ the popular current phr r e. But then in regard to truth we ought to diftinguifh (') 29, 37 136, '49- its ( 72 ) its meaning. It may fuffice to have made this declaration once for all, in order to avoid mi- ftakes. 156. The calidum innatum, the vital flame, or animal fpirit in man is fuppofed the caufe of all motions, in the fevcral parts of his body, whe- ther voluntary or natural. That is, it is the in- ftrument, 1 by means whereof the mind exerts and manifefts herfelf in the motions of the body. In the fame fenfe may not fire be faid to have force, to operate, and agitate the whole fyilem of the \vorid, which is held together and informed by one prefiding mind, and a'nimated throughout by one and the fame fiery fubftance, as an infr.ru.men- tal and mechanical agent, not -as a primary real efficient ? 157. This pure fpirit or invifible fire is ever ready to exert and mew itfelf in its effects ( 44- (/) H9 '5> '5 2 - fife., ( 75 ) fire, whofe particles they attract and adhere to (/('), there is produced a new fluid, more volatile than water or earth, and more fixed than fire. There- fore the virtues and operations imputed to air muft be ultimately attributed to fire, as that which im- parts activity to air itfelf. 164. The element of sethereal fire or light feems to comprehend, in a mixed ftate, the feeds, the natural caufes and forms (g) of all fubl unary things. The groffer bodies feparate, attract, and repe! the feveral confcituent particles of that heterogene- ous element ; which, being parted from the common, mafs, make diftinct efiences, producing and com- bining together fuch qualities and properties, as are peculiar to the feveral fubje,cts, and thence often ex- tracted in effential oils or odoriferous waters, from. r whence they exhale into the open air, and return into their original element. 165. Blue, red, yellow )s and other colours, have been difcbvered by Sir Ifaac Newton to depend on the parted rays or particles of light. And in like manner, a particular odour or flavour feemeth to depend on peculiar particles of light or fire (h] ; as appears from heat's being neceflfary to all vegetation whatfoever, and from the extreme minutenefs and volatility of thofe vegetable fouls or forms, flying off from the fubjects without any fenfible diminuti- on of their weight. Thefe particles, blended in one common ocean, mould feem to conceal the diftinct forms, but, parted and attracted by proper fub- jefts, difclofe or produce them. As the particles of light, which, when feparated, form diftinct co- lours, being blended are loft in one uniform ap- pearance. (*) H7- fe) 43- (*) 40- K 2 166. A- (76) 1 66. Agreeably thereto, an ethereal fubftance or fire was fuppofed by Heraclitus to be the feed cf the generation of all things, or that from which all things drew their original. The Stoics alfo taught, that all fubftance was originally fire and fhould return to fire : that an active fubtile fire was di&ufed or expanded throughout the whole uni- verfe ; the feveral parts whereof were produced, iuftained, and held together by it's force. And it was the opinion of the Pythagoreans, as Laertius informs us, that heat or fire was the principle of Jife animating the whole fyftern, and penetrating all the elements (a). The Platonifts too, as well as the Pythagoreans, held fire to be the immedi- ate natural agent, or animal fpirit ; to cherifh, to warm, to heat, to enlighten, to vegetate, to pro- duce the digeflions, circulations, fecretions, and or- ganical motions in all living bodies, vegetable or animal, being effects of that element, which, as it actuates the macrocofm, fo it animates the mi- crocofm. In the Timaeus of Plato, there is fuppo- fed fomething like a net of fire and rays of fire in a human body. Doth not this feem to mean the animal fpirit, flowing, or rather darting thro* the nerves ? 167. According to the Peripatetics, the form of heaven, or the fiery ethereal fubftance, contains the forms of all inferior being's (). It may be faid to teem with forms, and impart them to fubjects fitted to receive them. The vital force thereof in the Peripatetic fenfe is vital to all, but diverfly re- ceived according to the diverfity of the fubjects. So all colours are virtually contained in the light ; but their actual diftinctions of blue, red, yellow, and the reft, depend on the difTerenjce of the ob- jects which it illuftrates. Ariftotle in the book De (.*) '5 2 > '53- I*) 43. munda> ( 77 ) mnndo, fuppofeth a certain fifth efTence, an sethe- real nature unchangeable and impafllve -, and next in order a fubtile, flaming fubftance, lighted up, or fet on fire by that ethereal and divine nature. He fuppbfeth, indeed, that God is in heaven, but that his power, or a force derived from him, doth actuate and pervade the univerfe. 168. If we may credit Plutarch, Empedocles thought asther or heat to be Jupiter. -/Ether by the ancient philofophers was ufed to fignify pro- mifcuoufly fometimes fire and fometimes air. For they diftinguimed two forts of air. Plato in the Timaeus fpeaking of air, faith there are two kinds, the one mofe fine and fubtile, called asther ; the o- ther more grofs and replete with vapours. This asther, or purer medium, feems to have been the air or principle, from which all things, according to Anaximenes, derived their birth, and into which they were back again refolved at their death. Hip- pocrates, in his treatife De diasta, fpeaketh of a fire pure and invifible ; and this fire, according to him, is that which, flirring and giving move- ment to all things, caufes them to appear, or, as he ftyles it, come into evidence, that is, to ex- id, every one in it's time, and according to its deftiny. 169. This pure fire, sether, or fubftance of light, was accounted in itfelf invifible and im- perceptible to all our fenfes, being perceived only by it*s effects, fuch as heat, flame, and rarefaction. To which we may add, that the moderns pretend further to have perceived it by weight, inafmuchas the aromatic oils which mod abound with fire, as being the moft readily and vehemently enflamed, are above all others the heavieft. And by an ex- periment of Mr. Homberg's, four ounces of regu- lus of antimony, being calcined by a burning glafs for (78) for an hour together, were found to have imbibed and fi^ed feven drams of the fubftance of light. 170. Such is the rarefying and expanfive force of this element, as to produce in an inftant of time the greateft and mofl ftupendous effects : a fuffici- ent proof, not only of the power of fire, but alfo of the wifdom with which it is managed, and with- held from burfting forth every moment to the ut- 'ter ravage and deftruction of all things. And it is very remarkable, that this fame element, fo fierce and deflructive, fhould yet be fo varioufly temper- ed and applied, as to be withal the falutary warmth, the genial, cherifhing, and vital flame of all living treatures. It is not therefore to be wondered that Ariftotle thought the heat of a living body to be fomewhat divine and celeftial, derived from that pure aether to which he fuppofed the incorporeal deity faufisov uhg. Therefore though they looked on fire (/}as the TO jytyWHcov, or governing principle of the world ; yet it was not fimply fire, but ani- mated with a mind. 173. Such are the bright and lively fignatures of a divine mind, operating and difplaying itfelf in fire and light throughout the_ world, that, as Ari- ftotle obferves in his book De mundo, all things feem full of divinities, whofe apparitions on all fides flrike and dazzle our eyes. And it muft he J (f) '66. owne4 (8o ) owned, the chief philoibphers and wife men of antiquity, how much foever they attributed to fe- cond caufcs and the force of fire, yet they fuppofed a mind or intellect always refident therein, active or provident, reftraining it's force and directing it's operations. , 1 74. Thus Hipocrates, in his treatife De diseta, fpeaks of- a ftrong but invifible fire (), that rules all things without noife. Herein, faith he, refides foul, underftanding, prudence, growth, motion, dimunition, change, flcep, and waking. This is what governs all things and is never in repofe. And the fame author, in his tract De carnibus, after a ferious preface, fetting forth that he is about to de- clare his own opinion, expreJTeth it in thefe terms : " That which we call heat, B^cw, appears to me " fomething immortal, which underftands all *' things, which fees and knows both what is pre- " fent, apd what is to come." 175. This fame heat is alfo what Hippocrates calls nature, the author of life and death, good and evil. It is farther to be noted of this heat, that he maketh it the object of no fenfe. It is that occult, univer- fal nature, and inward invifible force, which actu- ates and animates the whole world, and was wor- fhipped by the ancients under the name of Saturn ; which Voffius judges, not improbably, to be derived from the Hebrew word Satar, to lye hidden or con- cealed. And what hath been delivered by Hip- pocrates agrees with the notions of other philofo- phers : Heraclitus (), for inftance, who held fire to be the principle and caufe of the generation of all things, did not mean thereby an inanimate ele- ment, but, as he termed it, nv ctsifuov, an ever. Jiving fire. (g) 1 68. (} 1 66. 176. Theo- 176. Theophraftus, in his book De igne, diftinguimeth between heat and fire. The fir It he confiders as a principle or caufe, not that which ap- peareth to ienfe as a paffion or accident exifting in a fubject, and which is in truth the effect of that unfeen principle. And it is remarkable, that he re- fers the treating of this invifible fire or heat, to the investigation of the firft caufes. Fire, the principle, is neither generated nor deftroyed, 'is every where and always prefent (a)\ while its ef- fects in different times and places fhew themfelves more or lefs, and are very various, loft, and cherifhing, or violent and destructive, terrible or agreeable, conveying good and evil, growth and decay, life and death, throughout the mundane fyftem. 177. It is allowed by all, that the Greeks deri- ved much of their philofophy from the Eaftern na- tions. And Heraclitus is thought by fome to have drawn his principles from Orpheus, as Or- pheus did from the Egyptians ; or, as others write, he had been auditor of Hippafus a Pythagorean, who held the fame notion of fire, and might have derived it from Egypt by his mafter Pythagoras, who had travelled into^Egypt, and been inftructed by the fages of that nation. One of whofe te- nets it was, that Sre was the principle of all action ; which is agreeable to the doctrine of the Stoics, that the whole of things is adminiftered by a fiery in- tellectual fpirit. In the Afclepian Dialogue, we find this notion, that all parts of the world vege- tate by a fine fubtil asther, which acts as an engine or inftrument, fubject to the will of the fuprcme God. 178. As the Platonifts held intellect to be lodged in foul, and foul in sether (If)', fo it pafieth (a) 43, (b) 157. L for (82 ) for a doctrine of Trifmegiftus in the Pimander, that mind is cloathed by ibul, and foul by ipirir. Therefore as the animal fpirit of man, being fub- til and luminous, is the immediate tegument of the human foul, or that wherein and whereby flic ads ; even fo the fpirit of the world, that active fiery ^ethereal fubftance of light, that permeates and animates the whole fyflem, is fuppofed to cloath the foul, which deaths the mind of the uni- verfe. 179. The Magi likewife faid of God, that he had light for his body and truth for his foul. And in the Chaldaic oracles, all things are fuppofed to be governed by a ^ icecv or intellectual fire. And in the fame oracles, the creative mind is faid to be cloathed with fire, 'Eo-eoipsvos TTM^ KU^ which oriental reduplication of the word fire, feems to imply the extreme purity and force thereof. Thus alfo in the Pfalms, Thou art clothed with light as with a garment. Where the word rendered light might have been rendered ,fire, the Hebrew letters being the fame with thofe in the word which figni- fies fire, all the difference being in the pointing, which is juftly counted a late invention. That other fcripture fentence is remarkable : Who ma- keth his minifters a flaming fire; which might, perhaps, be rendered, more agreeably to the con- text, as well as confidently with the Hebrew, after this manner: Who maketh flaming fire his mini- fters; and the whole might run thus: Who maketh the winds his meflengers, and flaming fire his mi- niilers. 1 80. A notion of fomething divine in fire, animating the whole world, and ordering its fe- veral parts, was a tenet of very general extent (a)> (a) 156, 157, 163, 1 65, 167, 1 68, 170, 172, 173, 174, 175. '77. & f - being (3) being embraced in the moft diflant times and places, even among the Chinefe themfelvesj who make tien, aether, or heaven, the fovereign prin- ciple, or caufe of all things, and teach, that the celeftial virtue, by them called li, when joined to corporeal fubftance, doth fafhion, diftinguifh, and fpecificate all natural beings. This li of the Chi- nefe feems to anfwer the forms of the Peripatetics. And both bear analogy to the foregoing philofo- phy of fire. iSr. The heaven is fuppcfed pregnant with virtues and forms, which constitute and difcrimi- nate the various fpecies of things. And we have more than once obferved, that, as the light, fire, or celeftial sther, being parted by refracting or reflecting bodies, produceth variety of colours j even fo, that fame apparently uniform fubftance, being parted and fecreted by the attracting and re- pelling powers of the divers fecretory ducts of plants and animals, that is, by natural chemiftry, produceth or imparteth the various fpecific pro- perties of natural bodies. Whence the taftes and odours and medicinal virtues fo various in vegeta- bles. 182. The tien is con fide red and adored by the Jearntd Chinefe, as living and intelligent cether, the 9ru vos\ of the Chaldsans and the Stoics. And the worfhip of things celcftial, the fun and flars, among the eaftern nations lefs remote, was on ac- count of their fiery nature, their heat and light, and the influence thereof. Upon thefe accounts, the fun was looked on by the Greek theologers -as the fpirit of the world, and the power of the world. The clcanfing quality, the light and heat of fire are natural fymbols of purity, knowledge, and power, or, if I may fo fay, the things them- L 2 fdves ( 84) felves, fo far as they are perceptible to our fenfes, or in the fame fenfe as motion is faid to be action. Accordingly, we find a religious regard was paid to fire, both by Greeks and Romans, and indeed by moft, if not all, the nations of the world. 183. The worfhip of Vefta at Rome was, in truth, the worfhip of fire. Nee tu aliud Veflam quam vivam intellige flam- mam, faith Ovid in his Fafti. And as in old Rome the eternal fire was religioufly kept by virgins, fo in Greece, particularly at Delphi and Athens, it xvas kept by widows. It was well known that Vulcan, or Fire, was worfhipped with great du ftinclion by the ./Egyptians. The Zabii or Sa- beans are alfo known to have been worfhippers of fire. It appears too from the Chaldsean ora- cles, that fire was regarded as divine by the fages of that nation. And it is fuppofed that Ur of the Cnaldseahs was fo called from the Hebrew word iignifying fire, becaufe fire was publickly wor- fhipped in that city. That a religious worfhip was d to fire by the ancient Perfians and their Ma- fted by all antiquity. And the feel of ., or old Gentils, of whom there are confi- able remains at this day both in the Mogol's country and in Perfia, doth teftify the fame. iS-j.. It doth not feem that their proftrations before the perpetual fires, preferved with great care in their Pyreia, or fire temples, were merely ;vil refpecl, as Dr. Hyde would have it thought. .hough he brings good proof that they do not )ke the fire on their altars, or pray to it, or call it God: and that they acknowledge a fupreme ifible deity. Civil refpeds are paid to things as related to civil power : but fuch relation doth not appear in the prefent cafe. It mould feem therefore, that they worfhip God as- prefent in the fire, which they worfhip or reverence, not ultimately or for itfelf, but relatively to the fu- preme being. Which it is not unlikely was elfe- where the cafe at firft; though the practice of men, efpecially of the vulgar, might in length of time degenerate from the original inftitution, and reft in the object of fenfe. 185. Doctor Hyde, in his hiftory of the re- ligion of the ancient Perfians, would have it thought, that they borrowed the ufe and reverence of perpetual fires, from the Jewifh practice pre- fcribed in the Levitical law, of keeping a per- petual fire burning on the altar. Whether that was the cafe or not, thus much one may venture to fay, it feems probable that whatever was the original of this cuftom among the Perfians, the like cuftoms among the Greeks and Romans were derived from the fame fource. 1 86. It muft be owned there are many paf- fages in holy fcripture (a), that would make one think, the fupreme being was in a peculiar man- ner prefent and manifeft in the element of fire. Not to infift that God is more than once faid to be a confuming fire, which might be underftood in a metaphorical fenfe, the divine apparitions were by fire, in the bum, at mount Sinai, on the tabernacle, in the cloven tongues. God is reprefented in the infpired writing?, as defcend- ing in s fire, as attended by fire, or with fire going before him. Celeftial things, as angels, chariots, and fuch like phenomena are inverted with fire, light, and fplendor. Ezekiel in his vifions beheld (*) 179- fire fire and brightnefs, lamps, burning coals of fire, and flafhes of lightening. In a vifion of Daniel the throne of God appeared like a fiery flame, and his wheels like burning fire. Alfo a fiery flame iffued and came forth from before him. 187. At the transfiguration, the apoftles faw our Saviour's face mining as the fun, and his rai- ment white as light, alfo a lucid cloud or body of light, out of which the voice came; which vifible light and fplendor was, not many centuries ago, maintained by the Greek church, to have been divine, and uncreated, and the very glory of God: as may be feen in the hiftory wrote by the emperor John Cantacuzene. And of late years bifhop Patrick gives it as his opinion, that in the beginning of the world, the Shecinah or divine prefence, which was then frequent and OP- dinary, appeared by light or fire. In commenting on that paffage, where Cain is faid to have gone out from the prefence of the Lord, the bifhop ob- lerves, that if Cain after this turned a downright idolater, as many think, it is very likely he in- troduced the worihip of the fun, as the beft re- femblance he could find of the glory of the Lord, which was wont to appear in a flaming light. It would be endlefs to enumerate all the paflages of holy fcripture, which confirm and illuftrate this notion, or reprefent the Deity as appearing and operating by fire. The mifconftruclion of which might poiTibly have mifled the Gnoftics, Bafilidians, and other ancient heretics into an opinion, that Jefus Chrift was the vifible corporeal fun. 1 8 8. We have feen, that in the moft remote ages and countries, the vulgar as well as the learn- ed, the inftitutions of lawgivers as well as the reafonings of philofophers, have ever confidered the [*) the element of ore in a peculiar light, and treated it with more than common regard, as if it were fomething of a very fmgular and extraordinary nature. Nor are there wanting authors of princi- pal account among the moderns, who entertain like notions concerning fire, efpecially among thofe who are moil converfant in that element, and ihould feem bed acquainted with it. 1 89. Mr. Homberg the famous modern chemift, who brought that art to fo great perfection, holds the fubftance of light or fire to be the true chemic principal fulphur (a\ and to extend itfelf through- out the whole univerfe. It is his opinion that this is the only active principle : That mixed with various things it formeth feveral forts of natural productions ; with falts making oil, with earth bitumen, with mercury metal : That this princi- ple of fulphur, fire, or the fubftance of light, is in itfelf imperceptible, and only becomes fenfible as it is joined with fome other principle, which ferves as a vehicle for it: That, although it be the moft active of all things, yet it is at the fame time the moft firm bond and cement to combine and hold the principles together, and give form to the mixed bodies : And, that in the analyfis of bodies it is always loft, efcaping the fkill of the artift, and paffing through the clofeft vefTels. 190. Boerhaave, Niewenty't, and divers other moderns are in the fame way of thinking. They with the ancients diftinguifh a pure, elementary, invisible fire from the culinary, or that which ap- pears in ignited bodies (b}. This laft they will not allow to be pure fire. The pure fire is to be dif- cerned by its effects alone; fuch as heat, dila- tation of all folid bodies, and rarefaction of fluids, (a) 129. (1} 163, 166. the ) the fegregating heterogeneous bodies, and con- gregating thofe that are homogeneous. That therefore which fmoakes and flames is not pure fire, but that which is collected in the focus of a mir- rour or burning glafs. This fire feems the fource of all the operations in nature : without it nothing either vegetates, or putrefies, lives, or moves or ferments, is difiblved, or compounded or altered, throughout this whole natural world in which we fubfift. Were it not for this, the whole would be one great flupid inanimate mafs. But this active element is luppofed to be every where, and always* prefent, imparting different degrees of life, heat, and motion, to the various animals, vegeta- bles, and other natural productions, as well as to the elements themfelves, wherein they are produced and nourifhed. 191. As water acts upon fait, or aqua fortis up- on iron, fo fire diiTolves all other bodies. Fire, air, and water are all three menftruums but the two laft feem to derive all their force and activity from the firft (a). And indeed there feems to be, originally or ultimately, but one menftruum in nature, to which all other menftruums may be reduced. Acid falts are a menftruum, but their force and diftinct powers are from fulphur. Con- fidered as pure, or in themfelves, they are all of the fame nature. But, as obtained by diftilla- tion, they are conftantly joined with fome ful- phur, which characlerizeth and cannot be fepa- rated from them. This is the doctrine of mon- fieur Homberg. But what is it that characteriz- eth or differenceth the fulphurs themfelves? If fulphur be the fubftance of light, as that author will have it, whence is it that animal, vege- () 149. table, (8 9 ) table, and metallic fulphurs impart different ties to the fame acid fak ? Can this be explained aipon Homberg's principles? And arc we not ob- liged to fuppofe, that light feparated by -the at- tracting and repelling powers -in the drainers, duels, and pores of thofe bodies, forms feveral di- ftinct kinds of fulphur, all which, before fuch fe- paration, were loft and blended together, in one common mafs of light or fire feemingly homoge- neous. 192. In the analyfis of inflammable bodies, the fire or fulphur is loir, and the diminution of weight fheweth the lofs (a). Oil is relblved into water, earth, and fait, none of which is inflammable. But the fire or vinculum which connected thofe things, and gave the form of oil, efcapes from the artift. It difappears, but is not deftroy. Light or fire impriioned made part of the com- pound, gave union to the other parts, and form to the whole. But having efcaped, it mingles with the general ocean of zether, till being agaift parted and attracted, it enters and fpeciiicar.es ion-ie new fubject of the animal, vegetable, or mineral kingdom. Fire therefore in the fenfe of philofo- phers is alfo fire, though not always flame. 193. Solar fire or light, in calcining certain bodies, is obferved to add to their weight. There is therefore no doubt but light can be fixed, and enter the compofition of a body. And though it fnould lye latent for a long time, yet, being fee free from its prifon, it (hall flill fhew itfelf to be fire. Lead, tin, or regulus of antimony, being expofed to the fire of a burning glafs, though they lofe much in fmoak and fleam, are nevertheleis found to be confidently increafed in weight, which proves the introduction of light or fire in- (a) 169. M to (9) to their pores. It is alfo obferved, that urine pro- duceth no phofphorus, unlefs it be Jong expofed to the folar light. From all which it may be con- cluded, that bodies attract and fix the light; whence it Ihould feem, as fome have obferved, that fire without burning is an ingredient in many things, as water without wetting. 194. Of this there cannot be a better proof, than the experiment of Monfieur Komberg, who made gold of mercury, by introducing light into its pores, but at fuch trouble and expence, that I fuppofe no body will try the experiment for pro- fit. By this junction of light and mercury, both bodies became fixed, and produced a third diffe- rent from either, to wit, real gold. For the truth of which fact, I refer to the memoirs of the French academy of Sciences. From the foregoing experiment it appears, that gold is only a mals of mercury penetrated and cemented by the Jub- ilance of light, the particles of thofe bodies attract- ing and fixing each other. This feems to have been not altogether unknown to former philofo- phers-, Marfilius Ficinus the Platonift, in his com- -raentary on the firft book of the fecond Ennead of PJotinus, and others, likewife before him, regard- ing mercury as the mother, and fulphur as the fa- ther of metals-, and Plato himfelf in his Timseus defcribing gold to be a denfe fluid with a fhining yellow light, which well fuits a competition ot Jight and mercury. 195. Fire or light mixeth with all bodies (a), even with water; witnefs the fkihing lights in the jea, whofe waves jfeem a frequently all on fire. Its operations are variou according to its kind, quantity, and degree of vehemence. One degree () '57- ( 9' ) keeps water fluid, another turns it into elaftic air (a}. And air itfeJf feems to be nothing die but vapours and exhalations, rendered elaftic by- fire. Nothing flames but oil : and fulphur with, water, fait, and earth compofe oil ; which fulphur is tire: therefore fire encloied attracts fire, and caufeth the bodies whofe competition it enters to burn and blaze. 196. Fire collected in the focus of a glafs ope- rates in vacuo, and therefore is thought not to need air to lupport it. Calx of lead hath gone off with an explofion in vacuo, which Niewenty't. and others take for a proof that fire can burn without air. But Mr. Hales attributes this effect to air enclofed in the red lead, and perhaps too in the receiver, which cannot be perfectly exhaufted. When common lead is put into the fire in order to make red-lead, a greater weight of this comes out than was put in of common Jead. Therefore the red-lead fhould feem impregnated with fire." Mr. Hales thinks it is with air. The vaft expanfion of compound aqua fortis, Mr. Niewenty't will have to proceed from fire alone. Mr. Hales contends that air muft necefTarily co-operate. Though by NiewentyYs experiment it fhould feem, the phot phorus burns equally, with and without air. 197. Perhaps they who hold the oppofite fides in this queftion, may be reconciled by obferving that air is in reality nothing more than particles of wet and dry bodies volatilifed, and rendered elaftic by fire (b). Whatever therefore is done by air muft be afcribed to fire, which fire is a fubtile invifible thing, whofe operation is not to bz dif- cerned but by means of fome groffer body, which (a) 149. (I) 147, 150, 151. M 2 ferves ( 92 ) > T CS not for a pabulum to nourifh the fire, but for a vehicle to arreft and bring it into view. Which feems the fole ufe of oil, air, or any other *hing, that vulgarly paficth for a pabulum or food of that element. 19^. To explain this matter more clearly, it is to be obferved, that fire, in order to become fen- fible, muft have fomc fubjeft to act upon. This being penetrated and agitated by fire affects us with light,, heat, or fome other fenfible alteration. And this fubjeft ib wrought upon may be called culinary fire. In the focus of a burning glafs ex- po fed to the fun, t-here is real actual fire, though' not difcerned by the fenfe, till it hath fomewhat to work on, and can" fhew itfelf in its effects, heat- ing, flaming, melting, and the like. Every ig- nited body is, in the foregoing fenfe, culinary fire. But it will not therefore follow, that it is conver- tible into pure elementary fire. This, for ought that appears, may be ingenerable and incorruptible by the courfe of nature. It may be fixed and im- prilbned in a compound (a), and yet retain its na- ture, though loft to fenfe, and though it return in- to the irwfible elementary mafs, upon the analyfis- of the compounded body : as is manifeft in the fo- iution of (tone lime by water. 199. It fhould feem, therefore, that what is faid f air's being the pabulum of fire, or being con- verted into fire, ought to be underftood only in this ienfe ; to wit, that air being leis grofs than- other bodies, is of a middle nature, and therefore more fit to receive the impreffions of a fine aethe- rial fire (),. and impart them to other things. Ac- cording to the antients, foul ferveth for a vehicle to (*) 169, 192, 193, (I) 163. (93) intellect (Vz)> and light or fire for z vehicle to foul; and, in like manner, air may be luppofed 2 vehicle to fire, fixing it in fome degree, and com- municating its effects to other bodies. 200. The pure invifible fire or aether doth per- meate all bodies, even the hardefl and moft foiid, as the diamond. This alone, therefore, cannot, as fome learned men have fuppofed, be the caufe of mufcular motion, by a mere impulfe of the nerves communicated from the brain to the membranes of the mufcles, and thereby to the enclofed sether, whofe expanfive motion, being by that means in- creafed, is thought to fwell the mufcles, and caufe a contraction oi the fielhy fibres. This, it mould feem, the pure sether cannot do immediately, and of itfelf, becaufe, fuppofing its expanfive motion to be increafed, it mutt itill pafs through the membranes, and confequently not fwell them, in- afmuch as aether is fuppofed freely to pervade the moft foiid bodies. It mould feem therefore, that this effect muft be owing, not to pure sether, but to sether in fome part fixed and arrefled by the par- ticles of air. 201. Although this sether be extremely elaftic, yet as it is fometimes found by experience to be attracted, imprifoned, and detained in grofs bodies (), fo we may fuppofe it to be attracted, and its expanfive force diminimed, though it fhould not be quite fixed, by the loofe particles of air, which combining and cohering therewith may bring it down, and qualify it for intercourfe with groffer things. Pure fire may be faid to animate air, and air other things. Pure fire is invifible ; therefore flame is not pure fire. Air is neceflfary both to life and flame. And it is found by experi- (a) 178. (i>) i6g. ment, (94) ment, that air lofeth in the lungs the power of feeding flame. Hence it is concluded, that the fame thing in air contributes both to life and flame. Vital flame furvives culinary flame in vacuo: there- fore it requires lefs of that thing to fuftain it. * 202. What this may be, whether fome certain proportion, or Ibme peculiar parrs of aether, is not eafy to fay. But thus much feems plain, that whatever is afcribed to acid may be alib afcribed to fire or sether. The particles of aether fly afun- der with the greateft force : therefore, agreeably to Sir Ilaac Newton's doctrine, when united they muft attract each other with the greateft force. There- fore they conftitute the acid. For whatfoever ilrongly attracts and is attracted, may be called an acid, as Sir Ifaac Newton informs us in his tract De acido. Hence it mould feem, that the fulphur of Homberg, and the acid of Sir Ifaac are at bot- tom one and the fame thing, to wit, pure fire or anher. 203. The vital flame or ^ethereal fpirit, being attracted and imprifoned in grofier bodies, feemeth to be fet free and carried off by the fuperior at- traction of a fubtil and pure flame. Hence, per- haps, it is that lightening kills animals, and turns ipirituous liquors vapid in an inftant. 204. Hippocrates, in his book concerning the Heart, obferveth, that the foul of man is not nou- riflied by meats and drinks from the lower belly, but by a pure and luminous fubftance, darting its rays and diftributing a non-natural nourifliment, as he terms it, in like manner as that from the in- teftines is diitributed to all parts of the body. This luminous non-natural nourifliment, though it be fecreted from the blood, is exprefly faid not to come from the lower belly. It is plain, therefore, he (95 ) he thought it came into the blood either by refpi- ration, or by attraction through the pores. And it muft be acknowledged, that fomewhat igneous or ethereal brought by the air into the blood feems to nourifh, though not the foul itfelf, yet the inte- rior tunicle of the foul, the aurai fimplicis ignem. 205. That there is really fuch a thing as vital flame, actually kindled, nourifhed, and extinguifhed like common flame, and by the fame means, is an opinion of fome moderns, particularly of Doctor Willis in his tract De fanguinis accenfione: that it requires conftant eventilation, through the trachea and pores of the body, for the difcharge of a fu- liginous and excrementitious vapour: and that this vital flame, being extremely fubtil, might not be feen any more than mining flies or ignes fatui by day-light. And yet it hath fometimes become vi- jfible on divers perfons, of which there are undoubt- ed inftances. This is Dr. Willis's notion: and perhaps there may be fome truth in this, if it be fo underftood, as that light or fire might indeed conftitute the animal fpirit or immediate vehicle of the foul. 206. There have not been wanting thofe, who, not content to fuppofe light the moil pure and re- fined of all corporeal beings, have gone farther, and beftowed upon it fome attributes of a yet high- er nature. Julianus the Platonic philofopher, as cited by Ficinusj faith, it was a doctrine in the theology of the Phoenicians, that there is diffiifed throughout the univerfe, a pellucid and fhining na- ture pure and impaffive, the act of a pure intelli- gence. And Ficinus himfelf undertakes to prove, that light is incorporeal, by feveral arguments: Be- caufe it enlightens and fills a great fpace in aM inftant, and without' oppofition: Becaufe feveral lights ( 96) lights meet -without refilling each other : Becaufe light cannot be defiled by filth of any kind: Be- ciufe the folar light is not fixed in any fubject: LaiUy, becaufe it contracts and expands itfelf fo eafily without collifion, condenfation, rarefaction, or delay throughout the wafted fpace. Thefc rear fons are given by Ficinus, in his comment on the firft book of the fecond Ennead of Plotinus. 207. But it is now well known, that light moves, that its motion is not inftantaneous : that it is capable of condenfation, rarefaction, and colli- fion: that it can be mixed with other bodies, en- ter their ccmpofition, and increafe their weigh}: (). All which feem fufficiently to overthrow fthofe arguments of Ficinus, and fhew light to be cor- poreal. There appears indeed fome difficulty at firft fight, about the non-refiftance of rays or par- ticles of light occurring one to another, in all pof- fible directions or from all points. Particularly, if we fuppofe the hollow furface of a large fphere, iludded with eyes looking inwards one at another, it may perhaps feem hard to conceive, howdiftind rays from every eye mould arrive at every other eye without juftling, repelling, and confounding each other. 20 S. But thefe difficulties may be got over by confidering in the firft place, that vifible points are not mathematical points, and confequently, that we are not to fuppofe every point of fpace a radiating point. " Secondly, by granting that many rays do refift and intercept each other, notwith- fhinding which the act of vifion may be perform- ed. Since as every point of the object is not i'een,. fo it is not nece'flary that rays from every iurh point arrive at the eye. We often fee :6o/ 192, 193, (97) an object, though more dimly, when many rays, are intercepted by a grofs medium. 209. Befides, we may fuppofe the particles of light to be indefinitely Imali, that is, as fmall as we pleafe, and their aggregate to bear as fmall a proportion to the void as we pleafe, there being nothing in this that contradicts the phenomena. . And there needs nothing more in order to con- ceive the pofilbility of rays pafiing from and to all vifible points, although they be not incorpo- real. Suppofe a hundred ports placed round a circular fea, and mips failing from each port to every other ; the larger the fea, and the fmalfer the veflels are fuppofed, the lefs danger will there be of their linking againft each other. But as there is by hypothefis no limited proportion be- tween the fea and the fhips, the void and folid particles of light, fo there is no difficulty that can oblige us to conclude the fun's light incorporeal from it's free pafiage ; efpecially when there are fo many clear proofs of the contrary. As for the difficulty, therefore, attending the fuppofidon of a fphere ftudded with eyes looking at each other, this is removed only by fuppofing the particles of light exceeding fmall relatively to the empty fpaces. 210. Plotinus fuppofeth, that from the fun's light which is corporeal, there fprings forth ano- ther equivocal light which is incorporeal, and as it were the brightnefs of the former. Marfilius Ficinus alfo, obferving it to be a doctrine in the Timaeus of Plato, that there is an occult fire or fpirit diffufed throughout the univerfe, intimates that this fame occult invifible fire or light is, as it were, the fight of the mundane foul. And Pio- tinus, in his fourth Ennead, fheweth it to be his opinion, that the world feeth it felf and all it's N parts. ( 9* ) parts. The Platonic philofophers do wonderfully refine upon light, and foar very high : from coal to flame , from flame to light ; from this vifible light to the occult light 'of the celcftial or mun- dane foul, which they fuppbfed to pervade and agitate the fubftance of the univefe by it's vigo- rous and expanfive motion. 211. If we may believe Diogenes Laertius, the Pythagorean philofophers thought there was a certain pure heat or fire, which had fomewhat di- vine in ir, by the participation whereof men be- came allied to the gods. And according to the Platonifts, heaven is not defined fo much by it's local fituation, as by it's purity. The pureft and moft excellent fire, that is heaveri, faith Ficinus. And again, the hidden fire that every where ex- erts it fclf, he calls celeftial. He reprefents fire as moft powerful and active, dividing all things, abhorring all compofition or mixture with other bodies. And, as foon as it goes free, relapfing inftantly into the common mafs of celeftial fire, which is every where prefent and latent. 212. This is the general fource of life, fpirit, and ftrength, and therefore of health to all ani- mals, who conftantly receive it's illapfes cloathed in air, through the lungs and pores of the body. The fame fpirir, imprifoned in food and medicines, is conveyed into the Itomach, the bowels, the lacteals, circulated and fecreted by the feveral duels, and diftributed throughout the fyftem (a). Plato, in his Timaeus, enumerating the ignited juices, names wine in the firft place, and tar in the fecond. But wine is prerled from the grape, and fermented by human induflry. Therefore of all ignited juices purely natural, tar or refm muft in his account be efteemed the firft. (") 37 4*> 44- 213. The ( 99 ) The vivifying luminous sther exifts in all places, even the darkeft caverns, as is evident from hence, that many animals fee in thofe dark- places, and that fire may be kindled in them by the collifion or attrition of bodies. It is alfb known, that certain perfons have fits of feeing in the dark. Tiberius was faid to have had this faculty or diftemper. I my.lelf knew an ingenious man, who had experienced it fcveral times in himfelf. And doctor Willis, in his tract De fanguinis ac- cenfione, mentions another of his own knowledge. This luminous aether or fpirit is therefore faid by Virgil, to nourifh or cherifh the innermoft earth, as well as the heavens and celeftial bodies. 'sol -Principio ccelum ac terras, campofque liquentes, Lucentemque globum Luns, Titaniaque aftra Spiritus intus alit. 214. The principles of motion and vegetation in living bodies feem to be delibations from the invifible nre or fpirit of the univerfe (a). Which, though prefent to all things, is not neverthelefs one way received by all ; but varioufly imbibed, attracted, and fecreted by the fine capillaries, and exquifite flrainers'in the bodies of plants and ani- mals, whereby it becomes mixed and detained in their juices. 215. It hath been thought by fomes obfervers of nature, that the fine glandular veflels admit from the common mafs of the blood, only fuch: juices as are homogeneous to thofe, with which they were originally imbued. How they came to be fo imbued doth not appear. But thus much, is. plain; that fine tubes attract fluids, that the glands are fine tubes, and that they attract very (,J 43 , 157/164, , 7f . * N 2 diffe- ( 1-00 ) different juices from the common mafs. The fame holds alib with regard to the capillary veffels ( are al- lowed to be incorporeal : the two intermediate -re colored, being capable of me: ion, rarefaction, gravity, and other qualities of bodies, It is fit to d;fi;nguim thefe things, in order to avoid am- biguity concerning the nature of fire.. 221. Sir Ifaac Nev/ton in his Optics, afks ; Is not fire a body heated fo hot as to emit light copioudy ? for what die, adds he, is a red hoc iron ihan fire ? Now it fhouM ieem, that to define fir^. by heat, would be to explain a thir.g by it felf. A body heated fo hot. as to emit iight is an ignited body, that is, hath fire in ir, is psr.ctra- ted and agitated by fire, but is not itklf fire. And although it fhould. in the third foregoing ac- ceptation, or vulgar fcnfc, pafs for fire, yet it is not the pure elementary (//) fire in the fc-cond or philofophic fenfe, fuch as was upderflood by the lages of antiquity, and fuch as is collected in the focus of a burning glafs j much lefs is it the vis, force, or power of burning, deftroying, calcining, melting, vitrifying, and railing the perceptions, of light and heat. This is truly and really in the incorporeal agent, and not in the vital fpirit of the univerfe. , Motion, and even power in an equivocal fenfe, may be found in this pure asthe- real fpirit, which ignites bodies, but is not itfelf the ignited body, being an inftrument or medium (c) by which the real agent doth operate on gr offer bodies. . . . . () '53 IS 6 * 57- (*) '9. (<0 160. 222, Ic 222. It hath been fliewrv in Sir Ifaac Newton's Optics, that light is not 'reflected by impinging on bodies, but by fome other caufe. And to him it feems probable, that as many rays as impinge oh the folid parts of the bodies, are not reflected but ftifled and retained in the bodies. And it is cer- tain, the great porofity of ail known bodies affords room for much of this light or fire to be lodged therein. Gold itfelf, the moft folid of all metals, fecms to have far more pores than folkl parts, from water being preficd through it in the Florentine ex- periment, from magnetic effluvia paffing, and from mercury entering its pores fo freely. And it is ad- mi'tted that water, though impofllble to be com- preffed, hath at lea ft forty times more pores than folid parts. And as acid particle?, joined with thofc of earth in certain proportions, are fo clofely united with them, as to be quite hid and loft to all appearance, as in mercurius dulcis and com?-- mon fulphur, fo alfo may we conceive the particles o'f light or fire to be abforbed and latent in groffer bodies. 223. It is the opinion of Sir Ifaac Newton, that fomewhat unknown remains in vacuo, when the air is exhaufted. This unknown medium he calls jEther. He fuppcfeth it to be more fubcil in its nature, and more iwift in its motion, than light, freely to pervade all bodies, and by its immenfe elafticity to be expanded throughout all the hea- vens. Its denfity is fuppofed greater in free and open fpaces, than within the pores of compact bodies. And, in pafling from the celeftial bodies to great dillances, it is fuppoied to grow denfi-r and denfer continually ; and thereby caule t' * great bodies to gravitate towards one another, 1 their re fpedive- parts towards their centers, ev r . body endeavouring to pafs from the denfer parts of the medium towards the rarer. 224. The extreme minutenefs of the parts of this medium, and the velocity of their motion, together with its gravity, denfity, and elaftic force, are 'thought to qualify it for being the caufe of all the natural motions in the univerfe. To this caufe arc afcribed the gravity and cohefion of bodies. The refraction of light is alfo thought to proceed from the different denfity and elaftic force of this sethe- real medium in different places. The vibrations of this medium alternately concurring with, or ob- flructing the motions of the rays of light, are fup- pofed to produce the fits of eafy reflexion and tranf- mifiion. Light by the vibrations of this medium is thought to communicate heat to bodies. Ani- mal motion and fenfation are alfo accounted for by the vibrating motions of this astherial medium, pro- pagated thro' the folid capiliaments of the nerves. In a word, all the phenomena and properties of bodies, that were before attributed to attraction, upon -later thoughts feem afcribed to this aether, together with the various attractions themfelves. 225. But in the philofophy of Sir Ifaac Newton, the fits (as they are called) of eafy tranlmiffion and reflexion, feem as well accounted for by vibrations excited in bodies by the rays of light, and the re- fraction of light by the attraction of bodies. To ex- plain the vibrations of light by thofe of a more fub- til medium, feems an uncouth explication. And gravity feems not an effect of the denfity and elafti- city of sether, but rather to be produced by fome other caufe ; which Sir Ifaac himfclf infinuates to have been the opinion even of thofe ancients who took vacuum, atoms, and the gravity of atoms for the principles of their philofophy, tacitly attri- ' buting L ( 10 5 ) buting (as* he ' well'obferves) gravity to fome other caulc diftinct from matter, from atoms, and confequently from that homogeneous sether or elartic fluid. The elafticity of which fluid is fup- pofcd to depend upon, to be defined and meafurcd by its denfity ; and this by the quantity of mat- ter in one particle, multiplied by the number of particles contained in a given fpace ; and the quan- tity of matter in any one particle or body of a given fize to be determined by its gravity. Should not therefore gravity feem the original property and firft fuppoied ? On the other hand, if force be confidered as prefcinded from gravity and mat- ter, and as exifting only in points or centers, what can this amount to but an abftract fpiritual incor- poreal force ? 226. It doth not feem neceffary from the phse- ncmena, to fuppofe any medium more active and fubtil than light or fire. Light being allowed to move at the rate of about ten millions of miles in a minute, what occafion is there to conceive ano- ther medium of ftill fmaller and more moVeable parts. Light or fire feems the fame with aether. So the ancients underftood, and fo the Greek word implies. It pervades all things (#), is every where prefent. And this fame fubtil medium, ac- cording to its various quantities, motions, and determinations, fheweth itfelf in different effects or appearances, and is asther, light, or fire. 227. The particles of aether fly afunder with the greateft force, therefore when united they muft (according to the Newtonian doctrine) at- tract each other with the greateft force ; therefore rhey are acids (), or conftitute the acid ; but this united with earthy parts maketh aikali, as Sir Ifaac teacheth in his trad De acido j alkali, as ap- (a] 157. (4) 130. O pears pears in cantharides and lixivial falts, is a cauftic * cauftics are fire -, therefore acid is fire ; therefore jedier is fire ; and if fire, light. We are not therefore obliged to admit a new medium diftin& from light, and of a finer and more exquifite fubflance, for the explication of phenomena, which appear to be as well explained without it. How can the denfity or elasticity of sether account for the rapid flight of a ray of light from the fun, ftill fwifter as it goes farther from the fun ? or how can it account for the various mo- tions and attractions of different bodies ? Why oil and water, mercury and iron repell, or why other bodies attract each other ? or why a parti- cle of light mould repell on one fide and attract on the other, as in the cafe of the Iflandic cry- ilal ? To explain cohefion by hamate atoms is ac- counted ignotum per ignotius. And is it not as much fo to account for the gravity of bodies by the elafticity of sether ? 228. It is one thing to arrive at general laws of nature from a contemplation of the phsenome- na ; and another to frame an hypothefis, and from thence deduce the phenomena. Thofe who fuppofed epicycles, and by them explained the motions and appearances of the planets, may not therefore be thought to have difcovered principles true in fact and nature. And albeit we may from the premifes infer a conclufion, it will not follow, that we can argue reciprocally, and from the conclufion infer the premifes. For inftance, fuppofing an elaftic fluid, whofe conftituent mi- nute particles are equidiftant from each other and of equal denfities and diameters, and recede one from another v/ith a centrifugal force which is in- verfly as the diftance of the centers, and admit- ting that from fuch fuppofition it muft follow, I hat ( 107) that the denfity and elaftic force of fuch fluid are in the inverfe proportion of the fpace it occupies when compreffed by any force ; yet we cannot re- ciprocally infer, that a fluid endued with this pro- perty muft therefore confift of fuch fuppofed equal particles ; for it would then follow, that the con- ftituent particles of air were of equal denfities and diameters ; whereas it is certain, that air is an he- terogeneous mafs, containing in its compofition an infinite variety of exhalations, from the dif- ferent bodies which make up this terraqueous globe. 229. The phenomena of light, animal fpirit, mufcular motion, fermentation, vegetation, and other natural operations, feem to require no- thing more than the intellectual and artificial fire of Heraclitus, Hippocrates, the Stoics (#), and other ancients. Intellect, fuperadded to astherial fpirit, fire, or light, moves, and moves regularly, proceeding, in a method as the Stoics, or incrcaf- ing and diminishing by mealure, as Heraclitus expreffed it. The Stoics held that fire compre- hended and included the fpermatic reafons or forms (Ao'ysff () 1 66, 1 6 8. () 164. O 2 nomena nomena of nature, than one uniform aetherial me- dium. 230. Ariftotle indeed excepts againft the ele- "ments being animated. Yet nothing hinders why that power of the foul, ftyled by him xi^mjf, or locomotive, may not refide therein, under the direction of an intellect, in fuch fenfe, and as properly as it is faid to refide in animal bodies. It muft neverthelefs be owned, chat albeit that philofopher acknowledgeth a divine force or ener- gy in fire, yet to fay that fire is alive, or that having a foul it mould not be alive, feem to him equally abfurd. See his fecond book De parti- bus animalium. 231. The laws of attraction and repulfion are to be regarded as laws of motion, and thefe only as rules or methods obferved in the productions of natural effects, the efficient and final cauics where- of are not of mechanical confideration. Certain- Jy, if the explaining a phenomenon be to af- fign its proper efficient and final caufc (a], it fhould feem the mechanical philofophers never explained any thing , their province being only to difcover the Jaws of nature, that is, the gene- ral rules and methods of motion, and to account for particular phenomena by reducing them un- der, or mewing their conformity to fuch general rules. 232. Some corpufcularian philofophers of the Jaft age have indeed attempted to explain the for- mation of this world and its phenomena, by a few fimple laws of mechanifm. 'But if we confider the various productions of nature, in the mine- ral, vegetable, and animal parts of the creation, I believe we mail feecaufe to affirm, that not any ?'. ,3i), and thereby wonderfully fupports the ceconomy of living bodies. By fuch peculiar com-r pofitions and attractions it feems to be effected, that denfer fluids can pafs where air itfelf cannot (as oil through leather) and therefore through (c] 41, ty) 152, 163. the ( "7 ) the niceft and fineft drainers of an animal or vege- table. 245. The ancients had Tome general conception of attracting and repelling powers (q) as natural princi- ples. Galilaei had particularly confidered the attrac- tion of gravity, and made fome difcovery of the laws thereof. But Sir Ifaac Newton by his fmgu- lar penetration, profound knowledge in geometry and mechanics, and great exactnefs in experiments, hath caft a new light on natural fcience. The laws of attraction and repulfion were in many inftances difcovered, and firft difcovered, by him. He fhewed their general extent, and therewith, as with a key, opened feveral deep fecrets of nature, in the knowledge whereof he feems to have made a great- er progrefs, than all the feels of corpufcularians together had done before him. Neverthelefs, the principle of attraction itfelf is not to be explained by phyfical or corporeal caufes. 246. The Cartefians attempted to explain it by the nifus of a fubtil element, receding from the center of its motion, and impelling grofler bodies towards it. Sir Ifaac Newton in his later thoughts feems (as was before obferved) to have adopted fomewhat not altogether foreign from this notion, afcribing that to his eiaftic medium (r) which Def- cartes did to his fecond element. But the great men of antiquity refolved gravity into the immediate action of an intelligent incorporeal being. To which alfo Sir Ifaac Newton himfelf attefts and fubfcribes, although he may perhaps fometimes be thought to forget himfelf, in his manner of fpeaking of phy- fical agents, which in a ftrict fenfe are none at alJ r and in fuppofmg real forces to exift in bodies, in (q) 241, 242. (r) 237, 238. which, ( "8 ) which, to fpeak truly, attradion and repulfioil ihould be confidered only as tendencies or motions 1 , that is, as mere effeds, and their laws as laws of motion. 247. Though it be fuppofed the chief bufme& of a natural philofopher to trace our caufes from the effects, yet this is to be understood not of agents (j) but of principles, that is, of component parts, in one fenfe, or of laws or rules, in another. In ftrid truth all agents are incorporeal, and as fucll are not properly of physical consideration. The Aftronomer, therefore, the Mechanic, or the Che- mift, not as fuch, but by accident only, treat of real caufes, agents or efficients. Neither doth it feem, as is fuppofed by the greatefl of mechanical philofophers, that the true way of proceeding in their fcience is, from known motions in nature to inveftigate the moving forces. Forafmuch as force is neither corporeal, nor belongs to any corporeal thing (/); nor yet to be dilcovered by experiments or mathematical reafonings, which reach no farther than difcernible effects, and motions in things pafilve' and moved. 248. Vis or force is to the foul, what extenfion is to the body, faith faint Auguftin, in his trad;" concerning the quantity of the Soul , and without force there is nothing done or made, and confequent- ly there can be no agent. Authority is not to de- cide in this cafe. Let any one confult his own no- tions and reafon, as well as experience, concerning the origin of motion, and the refpedive natures, properties, and differences of foul and body, and he will, if I miftake not, evidently perceive, that there is nothing adive in the latter. Nor are they natural 155. (t) 220, agents agents or corporeal forces, which make the parti- cles of bodies to cohere. Nor is it the bufmefs of experimental philofophers to find them out.' 249. The mechanical philofopher, as hath been already obferved, inquires properly concerning the rules and modes of operation alone, and not con- cerning the caufe, forafmuch as nothing mechanical is or really can be a caufe (). And although a mechanical or mathematical philofopher may fpeak of abfolute fpace, abiblute motion, and of force as exifting in bodies, caufing fuch motion and pro- portional thereto; yet what thefe forces are, which are fuppofed to be lodged in bodies, to be impreffed on bodies, to be multiplied, divided, and commu- nicated from one body to another, and which feem to animate bodies like abftraft fpirits or fouls, hath been found very difficult, not to fay impoffible, for thinking men to conceive and explain ; as may be feen by confulting Borellus De vi percuffionis, and Torricelli in his Lezioni academiche, among other authors. 250. Nor ; if we confider the proclivity of man- kind to realize their notions, will it feem ftrange that mechanic philofophers and geometricians fiiould, like other men, be mifled by prejudice, and take mathematical hypothefes for real beings exifting in bodies, fo far as even to make it the very aim and end of their fcience to compute or meafure thofe phantoms; whereas it is very certain that nothing in truth can be meafured * or computed, befide the very effects or motions themfelves. Sir Ifaac New- ton afks, Have not the minute particles of bodies certain forces or powers by which they act on. (u) 236, 247. This fubjeft is handled at large in my Latin trad De motu, publilhed above twenty years ago. one ( 120 ) one another, as well as on the particles of light, for producing moft of the phasnomema in nature ? But in reality, thofe minute particles are only agi- tated according to certain laws of nature, by fome other agent, wherein the force exifts and not in them, which have only the motion; which motion in the body moved, the Peripatetics rightly judge to be a mere paflion, but in the mover to be m^i* or act. 251. It paffeth with many, I know not how, that mechanical principles give a clear folution of the phenomena. The Democritic hypothefis, faith doctor Cudworth, doth much more handfomely and intelligibly folve the phenomena, than that of Ariflotle and Plato. But things rightly confidered, perhaps it will be found not to folve any phsenome- non at all. For all phenomena are, to fpeak tru- ly, appearances in the foul or mind; and it hath never been explained, nor can it be explained, how external bodies, figures, and motions mould pro- duce an appearance in the mind. Thofe principles, therefore, do not folve, if by. folving is meant aflign- ing, the real, either efficient or final, caufe of appear- ances, but only reduce them to general rules. 252. There is a certain analogy, conftancy, and uniformity in the phenomena or appearances of na- ture, which are a foundation for general rules : and thefe are a grammar for the understanding of na- ture, or that feries of effects in the vifible world, whereby we are enabled to fore fee what will come to pafs, in the natural courfe of things. Plotinus obferves, in his third Ennead, that the art of pre- faging is in fome fort the reading of natural letters denoting order, and that fo far forth as analogy ob- tains in the univerfe, there may be vaticination. And in reality, he that foretells the motions of the pla- planets, or the effefls of medicines, or the refult of chemical or mechanical experiments, may be laid to do it by natural vaticination. 253. We know a thing when we underftand it: and we underfland it, when we can interpret or tell what it fignifies. Strictly the fenfe knows nothing. We perceive indeed founds by hearing, and charac- ters by fight : but we are not therefore faid to un- derftand them. After the fame manner, the pha?- nomejia of nature are alike vifible to all : but all have not alike learned the connexion of natural things, or underfland what they fignify, or know how to vaticinate by them. There is no queftion, faith Socrates, in Theceteto, concerning that which is agreeable to each perfon ; but concerning what will in time to come be agreeable, of which all men are not equally judges. He who forcknoweth what will be in every kind, is the wifeft. According to Socrates, you and the cook may judge of a difh on the table equally well ; but while the dim is making, the cook can better foretcl what will enfue from this or that manner of compofing it. Nor is this manner of reafoning confined only to morals or po- litics ; but extends allb to natural fcience. 254. As the natural connexion of figns with the things fignified is regular and conftant, it forms a fort of rational difcourfc (tf), and is therefore the immediate effect of an intelligent caule. This is agreeable to the philofophy of Plato and other an- cients. PJotinus indeed faith, that which ads natu- rally is not intellection, but a certain power of mov- ing matter, which doth not know, but only do. And it mull be owned, that, as faculties are multi- plied by philolbphers according to their operations, the will ma be diftinuifhed from the Intel left. may ~i W fa- Q But But it will not therefore follow, that the will, which operates in the courfe of nature, is not conduced and applied by intelle6t, although it be granted that neither will underftands, nor intelle6l wills. There- fore, the phenomena of nature, which ftrike on the fenfes and are underftood by the mind, form not only a magnificent fpectacle, but alfo a moft coherent, entertaining, and inftructive difcourfe , and to effect this, they are conducted, adjufted, and ranged by the greateft w;fdom. This language or difcourfe is fludied with different attention, and in- terpreted with different degrees of fkill. But fo far as men have ftudied and remarked its rules, and can interpret right, fo far they may be faid to be knowing in nature. A beaft is like a man who hears a ftrange tongue, but underftands nothing. 255. Nature, faith the learned Doctor Cud- worth, is not mafter of art or wifdom : Nature is ratio merfa et confufa, rcafon immerfed and plung- ed into matter, and as it were fuddled in it and con- fcunded with it. But the formation of plants and animals, the motions of natural bodies, their va- rious properties, appearances, and viciffitudes, in a word, the whole ftries of things in this vifible world, which we call the courfe of nature, is fo wifely managed and carried on, that the moft improved human reafon cannot thoroughly comprehend even the leaft particle thereof ; fo far is it from feeming to be produced by fuddled or confounded reafon. 256. Natural productions, it is true, are not all equally perfect. But neither doth it fuit with the order of things, the ftructure of the univerfe, or the ends of providence, that they mould be fo. General rules, we have feen (