priestley in america - by edgar f. smith university of pennsylvania philadelphia p. blakiston's son & co. walnut street copyright, , by p. blakiston's son & co. the maple press york pa preface the writer, in studying the lives of early american chemists, encountered the name of _joseph priestley_ so frequently, that he concluded to institute a search with the view of learning as much as possible of the life and activities, during his exile in this country, of the man whom chemists everywhere deeply revere. recourse, therefore, was had to contemporary newspapers, documents and books, and the resulting material woven into the sketch given in the appended pages. if nothing more, it may be, perhaps, a connecting chapter for any future history of chemistry in america. its preparation has been a genuine pleasure, which, it is hoped by him whose hand guided the pen, will be shared by his fellow chemists, and all who are interested in the growth and development of science in this country. priestley in america there lies before the writer a tube of glass, eleven and one half inches in length and a quarter of an inch in diameter. its walls are thin. at one end there is evidence that an effort was made to bend this tube in the flame. ordinarily it would be tossed aside; but this particular tube was given the writer years ago by a great-grandson of joseph priestley. attached to the tube is a bit of paper upon which appear the words "piece of tubing used by priestley." that legend has made the tube precious in the heart and to the eye of the writer. everything relating to this wonderful figure in science, history, religion, politics and philosophy is very dear to him. on all sides of him are relics and reminders of priestley. not all, but many of his publications are near at hand. after perusal of these at various times, and while reading the many life sketches of priestley, there has come the desire to know more about his activities during the decade ( - ) he lived in america. isn't it fair to declare that the great majority of chemical students think of priestley as working only in england, his native land, and never give thought to his efforts during the last ten years of his life? it has been said that he probably inspired and incited the young chemists of this country to renewed endeavor in their science upon his advent here. there is no question that he influenced james woodhouse and his particular confreres most profoundly, as he did a younger generation, represented by robert hare. priestley again set in rapid motion chemical research in the young republic.[ ] he must therefore have done something himself. what was it? is it worth while to learn the character of this work? modern tendencies are antagonistic to the past. many persons care nothing for history. it is a closed book. they do not wish it to be opened, and yet the present is built upon the early work. in reviewing the development of chemistry in this country everything, from the first happening here, should be laid upon the table for study and reflection. thus believing, it will not be out of place to seek some light upon the occupation of the discoverer of oxygen after he came to live among us--with our fathers. noble-hearted, sympathetic thomas e. thorpe wrote: if, too, as you draw up to the fire 'betwixt the gloaming and the mirk' of these dull, cold november days, and note the little blue flame playing round the red-hot coals, think kindly of priestley, for he first told us of the nature of that flame when in the exile to which our forefathers drove him. right there, "the nature of the flame," is one thing priestley did explain in america. he discovered carbon monoxide--not in england, but in "exile."[ ] it may not be an epoch-making observation. there are not many such and those who make them are not legion in number. it was an interesting fact, with a very definite value, which has persisted through many succeeding decades and is so matter-of-fact that rarely does one arise to ask who first discovered this simple oxide of carbon. priestley was a man of strong human sympathies. he loved to mingle with men and exchange thoughts. furthermore, priestley was a minister--a preacher. he was ordained while at warrington, and gloried in the fact that he was a dissenting minister. it was not his devotion to science which sent him "into exile." his advanced thought along political and religious lines, his unequivocal utterances on such subjects,--proved to be the rock upon which he shipwrecked. it has been said-- by some strange irony of fate this man, who was by nature one of the most peaceable and peace-loving of men, singularly calm and dispassionate, not prone to disputation or given to wrangling, acquired the reputation of being perhaps the most cantankerous man of his time.... there is a wide-spread impression that priestley was a chemist. this is the answer which invariably comes from the lips of students upon being interrogated concerning him. the truth is that priestley's attention was only turned to chemistry when in the thirties by matthew turner, who lectured on this subject in the warrington academy in which priestley labored as a teacher. so he was rather advanced in life before the science he enriched was revealed to him in the experimental way. let it again be declared, he was a teacher. his thoughts were mostly those of a teacher. education occupied him. he wrote upon it. the old warrington academy was a "hot-bed of liberal dissent," and there were few subjects upon which he did not publicly declare himself as a dissenter. he learned to know our own delightful franklin in one of his visits to london. franklin was then sixty years of age, while priestley was little more than half his age. a warm friendship immediately sprang up. it reacted powerfully upon priestley's work as "a political thinker and as a natural philosopher." in short, franklin "made priestley into a man of science." this intimacy between these remarkable men should not escape american students. recall that positively fascinating letter ( ) from franklin to benjamin vaughan, in which occur these words: remember me affectionately ... to the honest heretic dr. priestley. i do not call him honest by way of distinction, for i think all the heretics i have known have been virtuous men. they have the virtue of fortitude, or they would not venture to own their heresy; and they cannot afford to be deficient in any of the other virtues, as that would give advantage to their many enemies.... do not however mistake me. it is not to my good friend's heresy that i impute his honesty. on the contrary 'tis his honesty that has brought upon him the character of heretic. much of priestley's thought was given to religious matters. in leeds he acknowledged himself a _humanitarian_, or a believer in the doctrine that jesus christ was in nature solely and truly a man, however highly exalted by god. his home in leeds adjoined a "public brew house." he there amused himself with experiments on carbon dioxide (fixed air). step by step he became strongly attracted to experimentation. his means, however, forbade the purchase of apparatus and he was obliged to devise the same and also to think out his own methods of attack. naturally, his apparatus was simple. he loved to repeat experiments, thus insuring their accuracy. in he published his first paper on pneumatic chemistry. it told of the impregnation of water with carbon dioxide. it attracted attention and was translated into french. this soda-water paper won for priestley the copley medal ( ). while thus signally honored he continued publishing views on theology and metaphysics. these made a considerable uproar. then came the memorable year of --the birth-year of oxygen. how many chemists, with but two years in the science, have been so fortunate as to discover an element, better still probably the most important of all the elements! it was certainly a rare good fortune! it couldn't help but make him the observed among observers. this may have occasioned the hue and cry against his polemical essays on government and church to become more frequent and in some instances almost furious. it was now that he repaired to london. here he had daily intercourse with franklin, whose encouragement prompted him to go bravely forward in his adopted course. it was in that he took up his residence in birmingham. this was done at the instance of his brother-in-law. the atmosphere was most congenial and friendly. then, he was most desirous of resuming his ministerial duties; further, he would have near at hand good workmen to aid him in the preparation of apparatus for his philosophical pursuits. best of all his friends were there, including those devoted to science. faujar st. fond, a french geologist has recorded a visit to priestley-- dr. priestley received me with the greatest kindness.... the building in which dr. priestley made his chemical and philosophical experiments was detached from his house to avoid the danger of fire. it consisted of several apartments on the ground floor. upon entering it we were struck with a simple and ingenious apparatus for making experiments on inflammable gas extracted from iron and water reduced to vapour. if, only, all the time of dr. priestley in birmingham had been devoted to science, but alas, his "beloved theology" claimed much of it. he would enter into controversy--he would dissent, and the awful hour was advancing by leaps and bounds. the storm was approaching. it burst forth with fury in . the houses of worship, in which he was wont to officiate, were the first to meet destruction, then followed his own house in which were assembled his literary treasures and the apparatus he had constructed and gathered with pains, sacrifice and extreme effort. its demolition filled his very soul with deepest sorrow. close at hand, the writer has a neat little chemical balance. it was brought to this country by priestley, and tradition has it, that it was among the pieces of the celebrated collection of chemical utensils rescued from the hands of the infuriated mob which sought even the life of priestley, who fortunately had been spirited or hidden away by loyal, devoted friends and admirers. in time he ventured forth into the open and journeyed to london, and when quiet was completely restored, he returned to one of his early fields of activity, but wisdom and the calm judgment of friends decided this as unwise. through it all priestley was quiet and philosophical, which is evident from the following story: a friend called on him soon after the riots and condoled with him for his loss in general, then mentioned the destruction of his books as an object of particular regret. priestley answered, "i should have read my books to little purpose if they had not taught me to bear the loss of them with composure and resignation." but the iron had entered his soul. he could not believe that in his own england any man would be treated as he had been treated. his country was dear to him. he prized it beyond expression, but he could not hope for the peace his heart craved. his family circle was broken, two of his sons having come to america, so in the end, deeply concerned for his life-companion's comfort, the decision to emigrate was reached, and their faces were turned to the west. in reviewing the history of chemistry the remark is frequently heard that one blotch on the fair escutcheon of french science was placed there when the remorseless guillotine ushered lavoisier into eternity. was not the british escutcheon of science dimmed when priestley passed into exile? priestley--who had wrought so splendidly! and yet we should not be too severe, for an illustrious name--count rumford--which should have been ours--was lost to us by influences not wholly unlike those which gained us priestley. benjamin thompson, early in life abandoned a home and a country which his fellow citizens had made intolerable. read priestley's volumes on air and on natural philosophy. they are classics. all conversant with their contents agree that the experimental work was marvelous. priestley's discovery of oxygen was epoch-making, but does not represent all that he did. twice he just escaped the discovery of nitrogen. one wonders how this occurred. he had it in hand. the other numerous observations made by him antedate his american life and need not be mentioned here. they alone would have given him a permanent and honorable rank in the history of chemistry. students of the science should reserve judgment of priestley until they have familiarized themselves with all his contributions, still accessible in early periodicals. when that has been done, the loss to english science, by priestley's departure to another clime will be apparent. his dearest friends would have held him with them. not every man's hand was against him--on the contrary, numerous were those, even among the opponents of his political and theological utterances, who hoped that he would not desert them. they regretted that he had-- turned his attention too much from the luminous field of philosophic disquisition to the sterile regions of polemic divinity, and the still more thorny paths of polemic politics.... from which the hope was cherished that he would recede and devote all his might to philosophical pursuits. a very considerable number ... of enlightened inhabitants, convinced of his integrity as a man, sincerity as a preacher, and superlative merit as a philosopher, were his strenuous advocates and admirers. but the die had been cast, and to america he sailed on april , , in the good ship _sansom_, capt. smith, with a hundred others--his fellow passengers. whilst on the seas his great protagonist lavoisier met his death on the scaffold. such was the treatment bestowed upon the best of their citizens by two nations which considered themselves as without exception the most civilized and enlightened in the world! it is quite natural to query how the grand old scientist busied himself on this voyage of eight weeks and a day. the answer is found in his own words: i read the whole of the greek testament, and the hebrew bible as far as the first book of samuel: also ovid's metamorphoses, buchanan's poems, erasmus' dialogues, also peter pindar's poems, &c.... and to amuse myself i tried the heat of the water at different depths, and made other observations, which suggest various experiments, which i shall prosecute whenever i get my apparatus at liberty. the doctor was quite sea-sick, and at times sad, but uplifted when his eyes beheld the proofs of friendship among those he was leaving behind. thus he must have smiled benignantly on beholding the elegant silver inkstand, with the following inscription, presented ... by three young gentlemen of the university of cambridge: "to joseph priestley, ll.d. &c. on his departure into exile, from a few members of the university of cambridge, who regret that expression of their esteem should be occasioned by the ingratitude of their country." and, surely, he must have taken renewed courage on perusing the valedictory message received from the society of united irishmen of dublin: sir, suffer a society which has been caluminated as devoid of all sense of religion, law or morality, to sympathize with one whom calumny of a similar kind is about to drive from his native land, a land which he has adorned and enlightened in almost every branch of liberal literature, and of useful philosophy. the emigration of dr. priestley will form a striking historical fact, by which alone, future ages will learn to estimate truly the temper of the present time. your departure will not only give evidence of the injury which philosophy and literature have received in your person, but will prove the accumulation of petty disquietudes, which has robbed your life of its zest and enjoyment, for, at your age no one would willingly embark on such a voyage, and sure we are, it was your wish and prayer to be buried in your native country, which contains the dust of your old friends saville, price, jebb, and fothergill. but be cheerful, dear sir, you are going to a happier world--the world of washington and franklin. in idea, we accompany you. we stand near you while you are setting sail. we watch your eyes that linger on the white cliffs and we hear the patriarchal blessing which your soul pours out on the land of your nativity, the aspiration that ascends to god for its peace, its freedom and its prosperity. again, do we participate in your feelings on first beholding nature in her noblest scenes and grandest features, on finding man busied in rendering himself worthy of nature, but more than all, on contemplating with philosophic prescience the coming period when those vast inland seas shall be shadowed with sails, when the st. lawrence and mississippi, shall stretch forth their arms to embrace the continent in a great circle of interior navigation: when the pacific ocean shall pour into the atlantic; when man will become more precious than fine gold, and when his ambition will be to subdue the elements, not to subjugate his fellow-creatures, to make fire, water, earth and air obey his bidding, but to leave the poor ethereal mind as the sole thing in nature free and incoercible. happy indeed would it be were men in power to recollect this quality of the human mind. suffer us to give them an example from a science of which you are a mighty master, that attempts to fix the element of mind only increase its activity, and that to calculate what may be from what has been is a very dangerous deceit.--were all the saltpetre in india monopolized, this would only make chemical researches more ardent and successful. the chalky earths would be searched for it, and nitre beds would be made in every cellar and every stable. did not that prove sufficient the genius of chemistry would find in a new salt a substitute for nitre or a power superior to it.[ ] it requires greater genius than mr. pitt seems to possess, to know the wonderful resources of the mind, when patriotism animates philosophy, and all the arts and sciences are put under a state of requisition, when the attention of a whole scientific people is bent to multiplying the means and instruments of destruction and when philosophy rises in a mass to drive on the wedge of war. a black powder has changed the military art, and in a great degree the manners of mankind. why may not the same science which produced it, produce another powder which, inflamed under a certain compression, might impell the air, so as to shake down the strongest towers and scatter destruction. but you are going to a country where science is turned to better uses. your change of place will give room for the matchless activity of your genius; and you will take a sublime pleasure in bestowing on britain the benefit of your future discoveries. as matter changes its form but not a particle is ever lost, so the principles of virtuous minds are equally imperishable; and your change of situation may even render truth more operative, knowledge more productive, and in the event, liberty itself more universal. wafted by the winds or tossed by the waves, the seed that is here thrown out as dead, there shoots up and flourishes. it is probable that emigration to america from the first settlement downward, has not only served the cause of general liberty, but will eventually and circuitously serve it even in britain. what mighty events have arisen from that germ which might once have been supposed to be lost forever in the woods of america, but thrown upon the bosom of nature, the breath of god revived it, and the world hath gathered its fruits. even ireland has contributed her share to the liberties of america; and while purblind statesmen were happy to get rid of the stubborn presbyterians of the north, they little thought that they were serving a good cause in another quarter.--yes! the volunteers of ireland still live--they live across the atlantic. let this idea animate us in our sufferings, and may the pure principles and genuine lustre of the british constitution reflected from their coast, penetrate into ourselves and our dungeons. farewell--great and good man! great by your mental powers, by your multiplied literary labours, but still greater by those household virtues which form the only solid security for public conduct by those mild and gentle qualities, which far from being averse to, are most frequently attended with severe and inflexible patriotism, rising like an oak above a modest mansion.--farewell--but before you go, we beseech a portion of your parting prayer to the author of good for archibald hamilton rowan, the pupil of jebb, our brother, now suffering imprisonment, and for all those who have suffered, and are about to suffer in the same cause--the cause of impartial and adequate representation--the cause of the constitution. pray to the best of beings for muir, palmer, skirving, margarott and gerald, who are now, or will shortly be crossing, like you, the bleak ocean, to a barbarous land!--pray that they may be animated with the same spirit, which in the days of their fathers, triumphed at the stake, and shone in the midst of flames. melancholy indeed, it is that the mildest and most humane of all religions should have been so perverted as to hang or burn men in order to keep them of one faith. it is equally melancholy, that the most deservedly extolled of civil constitutions, should recur to similar modes of coercion, and that hanging and burning are not now employed, principally, because measures apparently milder are considered as more effectual. farewell! soon may you embrace your sons on the american shore, and washington take you by the hand, and the shade of franklin look down with calm delight on the first statesman of the age extending his protection to its first philosopher. and how interestedly did america anticipate the arrival of the world renowned philosopher is in a measure foreshadowed by the following excerpt from the _american daily advertiser_ for thursday, june , : dr. priestley, with about one hundred other passengers, are on board the sansom, which may be hourly expected. in an editorial of the same paper, printed about the same date, there appeared the following tribute: it must afford the most sincere gratification to every well wisher to the rights of man, that the united states of america, the land of freedom and independence, has become the asylum of the greatest characters of the present age, who have been persecuted in europe, merely because they have defended the rights of the enslaved nations. the name of joseph priestley will be long remembered among all enlightened people; and there is no doubt that england will one day regret her ungrateful treatment to this venerable and illustrious man. his persecutions in england have presented to him the american republic as a safe and honourable retreat in his declining years; and his arrival in this city calls upon us to testify our respect and esteem for a man whose whole life has been devoted to the sacred duty of diffusing knowledge and happiness among nations. the citizens of united america know well the honourable distinction that is due to virtue and talents; and while they cherish in their hearts the memory of dr. franklin, as a philosopher, they will be proud to rank among the list of their illustrious fellow citizens, the name of dr. priestley. quietly but with great inward rejoicing were the travel-worn voyagers--the doctor and his wife--received on the evening of june , , at the old battery in new york, by their son joseph and his wife, who had long awaited them, and now conducted them to a nearby lodging house, which had been the head-quarters of generals howe and clinton. on the following morning the priestleys were visited by governor clinton, dr. prevost, bishop of new york and most of the principal merchants, and deputations of corporate bodies and societies, bringing addresses of welcome. thus, among the very first to present their sympathetic welcome was the democratic society of the city of new york, which in the address of its president, mr. james nicholson, made june , , said: sir, we are appointed by the democratic society of the city of new york, a committee to congratulate you on your arrival in this country: and we feel the most lively pleasure in bidding you a hearty welcome to these shores of liberty and equality. while the arm of tyranny is extended in most of the nations of the world, to crush the spirit of liberty, and bind in chains the bodies and minds of men, we acknowledge, with ardent gratitude to the great parent of the universe, our singular felicity in living in a land, where reason has successfully triumphed over the artificial distinctions of european policy and bigotry, and where the law equally protects the virtuous citizen of every description and persuasion. on this occasion we cannot but observe, that we once esteemed ourselves happy in the relation that subsisted between us and the government of great britain--but the multiplied oppressions which characterized that government, excite in us the most painful sensations, and exhibit a spectacle as disgusting in itself, as dishonourable to the british name. the governments of the old world present to us one huge mass of intrigue, corruption and despotism--most of them are now basely combined, to prevent the establishment of liberty in france, and to affect the total destruction of the rights of man. under these afflicting circumstances we rejoice that america opens her arms to receive, with fraternal affection, the friend of liberty and human happiness, and that here he may enjoy the best blessings of civilized society. we sincerely sympathize with you in all that you have suffered, and we consider the persecution with which you have been pursued by a venal court and an imperious and uncharitable priesthood, as an illustrious proof of your personal merit, and a lasting reproach to that government from the grasp of whose tyranny you are so happily removed. accept, sir, of the sincere and best wishes of the society whom we represent, for the continuance of your health, and the increase of your individual and domestic happiness. to which priestley graciously replied: gentlemen, viewing with the deepest concern, as you do, the prospect that is now exhibited in europe, those troubles which are the natural offspring of their forms of government originating, indeed, in the spirit of liberty, but gradually degenerating in tyrannies, equally degrading to the rulers and the ruled, i rejoice in finding an asylum from persecution in a country in which these abuses have come to a natural termination, and have produced another system of liberty founded on such wise principles, as, i trust, will guard it against all future abuses; those artificial distinctions in society, from which they sprung, being completely eradicated, that protection from violence which laws and government promise in all countries, but which i have not found in my own, i doubt not i shall find with you, though, i cannot promise to be a better subject of this government, than my whole conduct will evince that i have been to that of great britain. justly, however, as i think i may complain of the treatment i have met with in england i sincerely wish her prosperity, and, from the good will i bear both that country and this i ardently wish that all former animosities may be forgotten and that a perpetual friendship may subsist between them. and on monday, june, , , having taken the first opportunity to visit priestley, the tammany society presented this address: sir, a numerous body of freemen who associate to cultivate among them the love of liberty and the enjoyment of the happy republican government under which they live and who for several years have been known in this city, by the name of the tammany society have deputed us a committee to express to you their pleasure and congratulations on your safe arrival in this country. their venerable ancestors escaped, as you have done, from persecutions of intolerance, bigotry and despotism, and they would deem themselves, an unworthy progeny were they not highly interested in your safety and happiness. it is not alone because your various useful publications evince a life devoted to literature and the industrious pursuit of knowledge; not only because your numerous discoveries in nature are so efficient to the progression of human happiness: but they have long known you to be the friend of mankind and in defiance of calumny and malice, an asserter of the rights of conscience and the champion of civil and religious liberty. they have learned with regret and indignation the abandoned proceedings of those spoilers who destroyed your house and goods, ruined your philosophical apparatus and library, committed to the flames your manuscripts, pryed into the secrets of your private papers, and in their barbarian fury put your life itself in danger. they heard you also with exalted benevolence return unto them "blessings for curses:" and while you thus exemplified the undaunted integrity of the patriot, the mild and forbearing virtues of the christian, they hailed you victor in this magnanimous triumph over your enemies. you have fled from the rude arm of violence, from the flames of bigotry, from the rod of lawless power: and you shall find refuge in the bosom of freedom, of peace, and of americans. you have left your native land, a country doubtless ever dear to you--a country for whose improvement in virtue and knowledge you have long disinterestedly laboured, for which its rewards are ingratitude, injustice and banishment. a country although now presenting a prospect frightful to the eyes of humanity, yet once the nurse of science, of arts, of heroes, and of freeman--a country which although at present apparently self devoted to destruction, we fondly hope may yet tread back the steps of infamy and ruin, and once more rise conspicuous among the free nations of the earth. in this advanced period of your life, when nature demands the sweets of tranquility, you have been constrained to encounter the tempestous deep, to risk disappointed prospects in a foreign land, to give up the satisfaction of domestic quiet, to tear yourself from the friends of your youth, from a numerous acquaintance who revere and love you, and will long deplore your loss. we enter, sir, with emotion and sympathy into the numerous sacrifices you must have made, to an undertaking which so eminently exhibits our country as an asylum for the persecuted and oppressed, and into those regretful sensibilities your heart experienced when the shores of your native land were lessening to your view. alive to the impressions of this occasion we give you a warm and hearty welcome into these united states. we trust a country worthy of you; where providence has unfolded a scene as new as it is august, as felicitating as it is unexampled. the enjoyment of liberty with but one disgraceful exception, pervades every class of citizens. a catholic and sincere spirit of toleration regulates society which rises into zeal when the sacred rights of humanity are invaded. and there exists a sentiment of free and candid inquiry which disdains shackles of tradition, promising a rich harvest of improvement and the glorious triumphs of truth. we hope, sir, that the great being whose laws and works you have made the study of your life, will smile upon and bless you--restore you to every domestic and philosophical enjoyment, prosper you in every undertaking, beneficial to mankind, render you, as you have been to your own, the ornament of this country, and crown you at last with immortal felicity and honour. and to this the venerable scientist was pleased to say: gentlemen, i think myself greatly honoured, flying as i do, from ill treatment in my native country, on account of my attachment to the cause of civil and religious liberty, to be received with the congratulations of "a society of freemen associated to cultivate the love of liberty, and the enjoyment of a happy republican government." happy would our venerable ancestors, as you justly call them, have been, to have found america such a retreat for them as it is to me, when they were driven hither; but happy has it proved to me, and happy will it be for the world, that in the wise and benevolent order of providence, abuses of power are ever destructive of itself, and favourable to liberty. their strenuous exertions and yours now give me that asylum which at my time of life is peculiarly grateful to me, who only wish to continue unmolested those pursuits of various literature to which, without having ever entered into any political connexions my life has been devoted. i join you in viewing with regret the unfavourable prospect of great britain formerly, as you say, the nurse of science, and of freemen, and wish with you, that the unhappy delusion that country is now under may soon vanish, and that whatever be the form of its government it may vie with this country in everything that is favourable to the best interests of mankind, and join with you in removing that only disgraceful circumstance, which you justly acknowledge to be an exception to the enjoyment of equal liberty, among yourselves. that the great being whose providence extends alike to all the human race, and to whose disposal i cheerfully commit myself, may establish whatever is good, and remove whatever is imperfect from your government and from every government in the known world, is the earnest prayer of, gentlemen, your respectful humble servant. as priestley had ever gloried in the fact that he was a teacher, what more appropriate in this period of congratulatory welcome, could have come to him than the following message of new york's teaching body: the associated teachers in the city of new york beg leave to offer you a sincere and hearty welcome to this land of tranquility and freedom. impressed with the idea of the real importance of so valuable an acquisition to the growing interests of science and literature, in this country, we are particularly happy that the honour of your first reception, has fallen to this state, and to the city of new york. as labourers in those fields which you have occupied with the most distinguished eminence, at the arduous and important task of cultivating the human mind, we contemplate with peculiar satisfaction the auspicious influence which your personal residence in this country, will add to that of your highly valuable scientific and literary productions, by which we have already been materially benefited. we beg leave to anticipate the happiness of sharing in some degree, that patronage of science and literature, which it has ever been your delight to afford. this will give facility to our expressions; direct and encourage us in our arduous employments; assist us to form the man, and thereby give efficacy to the diffusion of useful knowledge. our most ardent wishes attend you, good sir, that you may find in this land a virtuous simplicity, a happy recess from the intriguing politics and vitiating refinements of the european world. that your patriotic virtues may add to the vigour of our happy constitution and that the blessings of this country may be abundantly remunerated into your person and your family. and we rejoice in believing, that the parent of nature, by those secret communications of happiness with which he never fails to reward the virtuous mind, will here convey to you that consolation, support, and joy, which are independent of local circumstances, and "which the world can neither give nor take away." touched, indeed was priestley by this simple, outspoken greeting from those who appreciated his genuine interest in the cause of education. hence his reply was in a kindred spirit: a welcome to this country from my fellow labourers in the instruction of youth, is, i assure you, peculiarly grateful to me. classes of men, as well as individuals, are apt to form too high ideas of their own importance; but certainly one of the most important is, that which contributes so much as ours do to the cummunication of useful knowledge, as forming the characters of men, thereby fitting them for their several stations in society. in some form or other this has been my employment and delight; and my principal object in flying for an asylum to this country, "a land," as i hope you justly term it, "of virtuous simplicity, and a recess from the intriguing politics, and vicious refinements of the european world," is that i may, without molestation, pursue my favourite studies. and if i had an opportunity of making choice of an employment for what remains of active exertion in life, it would be one in which i should as i hope i have hitherto done, contribute with you, to advance the cause of science, of virtue, and of religion. further, the medical society of the state of new york through dr. john charlton, its president, said: permit us, sir, to wait upon you with an offering of our sincere congratulations, on your safe arrival, with your lady and family in this happy country, and to express our real joy, in receiving among us, a gentleman, whose labours have contributed so much to the diffusion and establishment of civil and religious liberty, and whose deep researches into the true principles of natural philosophy, have derived so much improvement and real benefit, not only to the sciences of chemistry and medicine, but to various other arts, all of which are necessary to the ornament and utility of human life. may you, sir, possess and enjoy, here, uninterrupted contentment and happiness, and may your valuable life be continued a farther blessing to mankind. and in his answer dr. priestley remarked: i think myself greatly honoured in being congratulated on my arrival in this country by a society of persons whose studies bear some relation to my own. to continue, without fear of molestation, on account of the most open profession of any sentiments, civil or religious, those pursuits which you are sensible have for their object the advantage of all mankind, (being, as you justly observe, "necessary to the ornament and utility of human life") is my principal motive for leaving a country in which that tranquility and sense of security which scientificial pursuits require, cannot be had; and i am happy to find here, persons who are engaged in the same pursuits, and who have the just sense that you discover of their truly enviable situation. as a climax to greetings extended in the city of new york, the republican natives of great britain and ireland resident in that city said, we, the republican natives of great britain and ireland, resident in the city of new york, embrace, with the highest satisfaction, the opportunity which your arrival in this city presents, of bearing our testimony to your character and virtue and of expressing our joy that you come among us in circumstances of such good health and spirits. we have beheld with the keenest sensibility, the unparallelled persecutions which attended you in your native country, and have sympathized with you under all their variety and extent. in the firm hope, that you are now completely removed from the effects of every species of intolerance, we most sincerely congratulate you. after a fruitless opposition to a corrupt and tyrannical government, many of us have, like you, sought freedom and protection in the united states of america; but to this we have all been principally induced, from the full persuasion, that a republican representative government, was not merely best adapted to promote human happiness, but that it is the only rational system worthy the wisdom of man to project, or to which his reason should assent. participating in the many blessings which the government of this country is calculated to insure, we are happy in giving it this proof of our respectful attachment:--we are only grieved, that a system of such beauty and excellence, should be at all tarnished by the existence of slavery in any form; but as friends to the equal rights of man, we must be permitted to say, that we wish these rights extended to every human being, be his complexion what it may. we, however, look forward with pleasing anticipation to a yet more perfect state of society; and, from that love of liberty which forms so distinguishing a trait in american character, are taught to hope that this last--this worse disgrace to a free government, will finally and forever be done away. while we look back on our native country with emotions of pity and indignation at the outrages which humanity has sustained in the persons of the virtuous muir, and his patriotic associates; and deeply lament the fatal apathy into which our countrymen have fallen; we desire to be thankful to the great author of our being that we are in america, and that it has pleased him, in his wise providence, to make the united states an asylum not only from the immediate tyranny of the british government, but also from those impending calamities, which its increasing despotism and multiplied iniquities, must infallibly bring down on a deluded and oppressed people. accept, sir, of our affectionate and best wishes for a long continuance of your health and happiness. the answer of the aged philosopher to this address was: i think myself peculiarly happy in finding in this country so many persons of sentiments similar to my own, some of whom have probably left great britain or ireland on the same account, and to be so cheerfully welcomed by them on my arrival. you have already had experience of the difference between the governments of the two countries, and i doubt not, have seen sufficient reason to give the decided preference that you do to that of this. there all liberty of speech and of the press as far as politics are concerned, is at an end, and a spirit of intolerance in matters of religion is almost as high as in the time of the stuarts. here, having no countenance from government, whatever may remain of this spirit, from the ignorance and consequent bigotry, of former times, it may be expected soon to die away; and on all subjects whatever, every man enjoys invaluable liberty of speaking and writing whatever he pleases. the wisdom and happiness of republican governments and the evils resulting from hereditary monarchical ones, cannot appear in a stronger light to you than they do to me. we need only look to the present state of europe and of america, to be fully satisfied in this respect. the former will easily reform themselves, and among other improvements, i am persuaded, will be the removal of that vestige of servitude to which you allude, as it so ill accords with the spirit of equal liberty, from which the rest of the system has flowed; whereas no material reformation of the many abuses to which the latter are subject, it is to be feared, can be made without violence and confusion. i congratulate you, gentlemen, as you do me, on our arrival in a country in which men who wish well to their fellow citizens, and use their best endeavours to render them the most important services, men who are an honour to human nature and to any country, are in no danger of being treated like the worst felons, as is now the case in great britain. happy should i think myself in joining with you in welcoming to this country every friend of liberty, who is exposed to danger from the tyranny of the british government, and who, while they continue under it, must expect to share in those calamities, which its present infatuation must, sooner or later, bring upon it. but let us all join in supplications to the great parent of the universe, that for the sake of the many excellent characters in our native country its government may be reformed, and the judgments impending over it prevented. the hearty reception accorded dr. priestley met in due course with a cruel attack upon him by william cobbett, known under the pen-name of peter porcupine, an englishman, who after arrival in this country enjoyed a rather prosperous life by formulating scurrilous literature--attacks upon men of prominence, stars shining brightly in the human firmament. an old paper, the _argus_, for the year , said of this peter porcupine: when this political caterpillar was crawling about at st. john's, nova scotia, in support of his britannic majesty's glorious cause, against the united states, and holding the rank of serjeant major in the th regiment, then quartered in that land, "flowing with milk and honey," and grindstones, and commanded by colonel bruce; it was customary for some of the officers to hire out the soldiers to the country people, instead of keeping them to military duty, and to pocket the money themselves. peter found he could make a _speck_ out of this, and therefore kept a watchful eye over the sins of his superiors. when the regiment was recalled and had returned to england--peter, brimful of amor patriæ, was about to prefer a complaint against the officers, when they came down with a round sum of the ready rino, and a promise of his discharge, in case of secrecy.--this so staggered our incorruptible and independent hero and quill driver, that he agreed to the terms, received that very honorable discharge, mentioned with so much emphasis, in the history of his important life--got cash enough to come to america, by circuitous route and to set himself up with the necessary implements of scandal and abuse. this flea, this spider, this corporal, has dared to point his impotent spleen at the memory of that illustrious patriot, statesman and philosopher, benjamin franklin. let the buzzing insect reflect on this truth--that "succeeding times great franklin's works shall quote, when 'tis forgot--this peter ever wrote." and the _advertiser_ declared: peter porcupine is one of those writers who attempt to deal in wit--and to bear down every republican principle by satire--but he miserably fails in both, for his wit is as stale as his satire, and his satire as insipid as his wit. he attempts to ridicule dr. franklin, but can any man of sense conceive any poignancy in styling this great philosopher, "poor richard," or "the old lightning rod." franklin, whose researches in philosophy have placed him preeminent among the first characters in this country, or in europe: is it possible then that such a contemptible wretch as peter porcupine, (who never gave any specimen of his philosophy, but in bearing with christian patience a severe whipping at the public post) can injure the exalted reputation of this great philosopher? the folly of the editor of the centinal, is the more conspicuous, in inserting his billingsgate abuse in a boston paper, when this town, particularly the tradesman of it are reaping such advantages from franklin's liberality. the editor of the centinal ought to blush for his arrogance in vilifying this tradesmen's friend, by retailing the scurrility of so wretched a puppy as peter porcupine. as to dr. priestley, the editor was obliged to apologise in this particular--but colours it over as the effusions of genius--poor apology, indeed to stain his columns with scurrility and abuse, and after finding the impression too notoriously infamous, attempts to qualify it, sycophantic parenthesis. the names of franklin and priestley will be enrolled in the catalogue of worthies, while the wretched peter porcupine, and his more wretched supporters, will sink into oblivion, unless the register of newgate should be published, and their memories be raked from the loathsome rubbish as spectres of universal destestation. and the london monthly review (august , ) commented as follows on porcupine's animadversions upon priestley: frequently as we have differed in opinion from dr. priestley, we should think it an act of injustice to his merit, not to say that the numerous and important services which he has rendered to science, and the unequivocal proofs which he has given of at least honest intention towards religion and christianity ought to have protected him from such gross insults as are poured upon him in this pamphlet. of the author's literary talent, we shall say but little: the phrases, "setting down to count the cost"--"the rights of the man the greatest bore in nature"--the appellation of rigmarole ramble, given to a correct sentence of dr. priestley--which the author attempts to criticise--may serve as specimens of his language. the pitiful attempt at wit, in his vulgar fable of the pitcher haranguing the pans and jordans, will give him little credit as a writer, with readers of an elegant taste.--no censure, however, can be too severe for a writer who suffers the rancour of party spirit to carry him so far beyond the bounds of justice, truth and decency, as to speak of dr. priestley as an admirer of the massacres of france, and who would have wished to have seen the town of birmingham like that of lyons, razed, and all its industrious and loyal inhabitants butchered as a man whose conduct proves that he has either an understanding little superior to that of an idiot, or the heart of marat: in short, as a man who fled into banishment covered with the universal destestation of his countrymen. the spirit, which could dictate such outrageous abuse, must disgrace any individual and any party. even before porcupine began his abuse of priestley, there appeared efforts intended no doubt to arouse opposition to him and dislike for him. one such, apparently very innocent in its purpose, appeared shortly after priestley's settlement in northumberland. it may be seen in _the advertiser_, and reads thus: the divinity of jesus christ proved in a publication to be sold by francis bayley in market street, between rd and th streets, at the sign of the _yorick's head_--being a reply to dr. joseph priestley's appeal to the serious and candid professors of christianity. the new york addresses clearly indicated the generous sympathy of hosts of americans for priestley. they were not perfunctory, but genuinely genuine. this brought joy to the distinguished emigrant, and a sense of fellowship, accompanied by a feeling of security. more than a century has passed since these occurrences, and the reader of today is scarcely stirred by their declarations and appeals. changes have come, in the past century, on both sides of the great ocean. almost everywhere reigns the freedom so devoutly desired by the fathers of the long ago. it is so universal that it does not come as a first thought. other changes, once constantly on men's minds have gradually been made. how wonderful has been the development of new york since priestley's brief sojourn in it. how marvelously science has grown in the great interim. what would priestley say could he now pass up and down the famous avenues of our greatest city? his decision to live in america, his labors for science in this land, have had a share in the astounding unfolding of the dynamical possibilities of america's greatest municipality. the priestleys were delighted with new york. they were frequent dinner guests of governor clinton, whom they liked very much and saw often, and they met with pleasure dr. samuel l. mitchill, the professor of chemistry in columbia. amidst the endless fetes, attendant upon their arrival, there existed a desire to go forward. the entire family were eager to arrive at their real resting place--the home prepared by the sons who had preceded them to this western world. accordingly, on june , , they left new york, after a fortnight's visit, and the _advertiser_ of philadelphia, june , , contained these lines: last thursday evening arrived in town from new york the justly celebrated philosopher dr. joseph priestley. thus was heralded his presence in the city of his esteemed, honored friend, franklin, who, alas! was then in the spirit land, and not able to greet him as he would have done had he still been a living force in the city of brotherly love. however, a very prompt welcome came from the american philosophical society, founded ( ) by the immortal savant, franklin. the president of this venerable society, the oldest scientific society in the western hemisphere, was the renowned astronomer, david rittenhouse, who said for himself and his associates: the american philosophical society, held at philadelphia for promoting useful knowledge, offer you their sincere congratulations on your safe arrival in this country. associated for the purposes of extending and disseminating those improvements in the sciences and the arts, which most conduce to substantial happiness of man, the society felicitate themselves and their country, that your talents and virtues, have been transferred to this republic. considering you as an illustrious member of this institution: your colleagues anticipate your aid, in zealously promoting the objects which unite them; as a virtuous man, possessing eminent and useful acquirements, they contemplate with pleasure the accession of such worth to the american commonwealth, and looking forward to your future character of a citizen of this, your adopted country, they rejoice in greeting, as such, an enlightened republican. in this free and happy country, those unalienable rights, which the author of nature committed to man as a sacred deposit, have been secured: here, we have been enabled, under the favour of divine providence, to establish a government of laws, and not of men; a government, which secures to its citizens equal rights, and equal liberty, and which offers an asylum to the good, to the persecuted, and to the oppressed of other climes. may you long enjoy every blessing which an elevated and highly cultivated mind, a pure conscience, and a free country are capable of bestowing. and, in return, priestley remarked. it is with peculiar satisfaction that i receive the congratulations of my brethren of the philosophical society in this city, on my arrival in this country. it is, in great part, for the sake of pursuing our common studies without molestation, though for the present you will allow, with far less advantage, that i left my native country, and have come to america; and a society of philosophers, who will have no objection to a person on account of his political or religious sentiments, will be as grateful, as it will be new to me. my past conduct, i hope, will show, that you may depend upon my zeal in promoting the valuable objects of your institution; but you must not flatter yourself, or me, with supposing, that, at my time of life, and with the inconvenience attending a new and uncertain settlement, i can be of much service to it. i am confident, however, from what i have already seen of the spirit of the people of this country, that it will soon appear that republican governments, in which every obstruction is removed to the exertion of all kinds of talent, will be far more favourable to science, and the arts, than any monarchical government has ever been. the patronage to be met with there is ever capricious, and as often employed to bear down merit as to promote it, having for its real object, not science or anything useful to mankind, but the mere reputation of the patron, who is seldom any judge of science. whereas a public which neither flatters nor is to be flattered will not fail in due time to distinguish true merit and to give every encouragement that it is proper to be given in the case. besides by opening as you generously do an asylum to the persecuted and "oppressed of all climes," you will in addition to your own native stock, soon receive a large accession of every kind of merit, philosophical not excepted, whereby you will do yourselves great honour and secure the most permanent advantage to the community. doubtless in the society of so many worthy philadelphians, the priestleys were happy, for they had corresponded with not a few of them. the longing for northumberland became very great and one smiles on reading that the good doctor thought "philadelphia by no means so agreeable as new york ... philadelphia would be very irksome to me.... it is only a place for business and to get money in." but in this city he later spent much of his time. it was about the middle of july, , that the journey to northumberland began, and on september , , priestley wrote of northumberland "nothing can be more delightful, or more healthy than this place." safely lodged among those dear to him one finds much pleasure in observing the great philosopher's activities. the preparation of a home for himself and his wife and the unmarried members of the family was uppermost in his mind. but much time was given to correspondence with loyal friends in england. chief among these were the reverends lindsey and belsham. the letters to these gentlemen disclose the plans and musings of the exile. for instance, in a communication to the former, dated september , , he wrote: the professor of chemistry in the college of philadelphia is supposed to be on his death-bed ... in the case of a vacancy, dr. rush thinks i shall be invited to succeed him. in this case i must reside four months in one year in philadelphia, and one principal inducement with me to accept of it will be the opportunity i shall have of forming an unitarian congregation.... and a month later he observed to the same friend: philadelphia is unpleasant, unhealthy, and intolerably expensive.... every day i do something towards the continuation of my church history.... i have never read so much hebrew as i have since i left england.... he visited freely in the vicinity of northumberland, spending much time in the open. davy, a traveler, made this note: dr. priestley visited us at sunbury, looks well and cheerful, has left off his perriwig, and combs his short grey locks, in the true style of the simplicity of the country.... dined very pleasantly with him. he has bought a lot of eleven acres (exclusively of that which he is building on), which commands a delightful view of all the rivers, and both towns, i.e. sunbury and northumberland and the country. it cost him £ currency. it was also to mr. lindsey that he communicated, on november , , a fact of no little interest, even today, to teachers of chemistry in america. it was: i have just received an invitation to the professorship of chemistry at philadelphia ... when i considered that i must pass four months of every year from home, my heart failed me; and i declined it. if my books and apparatus had been in philadelphia, i might have acted differently, but part of them are now arrived here, and the remainder i expect in a few days, and the expense and risk of conveyance of such things from philadelphia hither is so great, that i cannot think of taking them back ... and in a year or two, i doubt not, we shall have a college established here. it was about this time that his youngest son, harry, in whom he particularly delighted, began clearing acres of cheap land, and in this work the philosopher was greatly interested; indeed, on occasions he actually participated in the labor of removing the timber. despite this manual labor there were still hours of every day given to the church history, and to his correspondence which grew in volume, as he was advising inquiring english friends, who thought of emigrating, and very generally to them he recommended the perusal of dr. thomas cooper's "advice to those who would remove to america--" through this correspondence, now and then, there appeared little animadversions on the quaint old town on the delaware, such as i never saw a town i liked less than philadelphia. could this dislike have been due to the fact that-- probably in no other place on the continent was the love of bright colours and extravagance in dress carried to such an extreme. large numbers of the quakers yielded to it, and even the very strict ones carried gold-headed canes, gold snuff-boxes, and wore great silver buttons on their drab coats and handsome buckles on their shoes. and nowhere were the women so resplendant in silks, satins, velvets, and brocades, and they piled up their hair mountains high. furthermore-- the descriptions of the banquets and feasts ... are appalling. john adams, when he first came down to philadelphia, fresh from boston, stood aghast at this life into which he was suddenly thrown and thought it must be sin. but he rose to the occasion, and, after describing in his diary some of the "mighty feasts" and "sinful feasts" ... says he drank madeira "at a great rate and found no inconvenience." it would only be surmise to state what were the doctor's reasons for his frequent declaration of dislike for philadelphia. the winter of - proved much colder "than ever i knew it in england," but he cheerfully requested samuel parker to send him a hygrometer, shades or bell-glasses, jars for electrical batteries, and a set of glass tubes with large bulbs at the end, such as i used in the experiments i last published on the generation of _air_ from water. most refreshing is this demand upon a friend. it indicates the keen desire in priestley to proceed with experimental studies, though surroundings and provisions for such undertakings were quite unsatisfactory. the spirit was there and very determined was its possessor that his science pursuits should not be laid totally aside. his attitude and course in this particular were admirable and exemplary. too often the lack of an abundance of equipment and the absence of many of the supposed essentials, have been deterrents which have caused men to abandon completely their scientific investigations. however, such was not the case with the distinguished exile, and for this he deserved all praise. from time to time, in old papers and books of travel, brief notes concerning priestley appear. these exhibit in a beautiful manner the human side of the man. they cause one to wish that the privilege of knowing this worthy student of chemical science might have been enjoyed by him. for example, a mr. bakewell chanced upon him in the spring of and recorded: i found him (priestley) a man rather below the middle size, straight and plain, wearing his own hair; and in his countenance, though you might discern the philosopher, yet it beamed with so much simplicity and freedom as made him very easy of access. it is also stated in davy's "journal of voyage, etc."-- the doctor enjoys a game at whist; and although he never hazards a farthing, is highly diverted with playing good cards, but never ruffled by bad ones. in may, , priestley expressed himself as follows: as to the experiments, i find i cannot do much till i get my own house built. at present i have all my books and instruments in one room, in the house of my son. this is the first time in all his correspondence that reference is made to experimental work. it was in . as a matter of course every american chemist is interested to know when he began experimentation in this country. in the absence of proper laboratory space and the requisite apparatus, it is not surprising that he thought much and wrote extensively on religious topics, and further he would throw himself into political problems, for he addressed mr. adams on restriction "in the naturalization of foreigners." he remarked that-- party strife is pretty high in this country, but the constitution is such that it cannot do any harm. to friends, probably reminding him of being "unactive, which affects me much," he answered: as to the chemical lectureship (in philadelphia) i am convinced i could not have acquitted myself in it to proper advantage. i had no difficulty in giving a general course of chemistry at hackney (england), lecturing only once a week; but to give a lecture every day for four months, and to enter so particularly into the subject as a course of lectures in a medical university (pennsylvania) requires, i was not prepared for; and my engagements there would not, at my time of life, have permitted me to make the necessary preparations for it; if i could have done it at all. for, though i have made discoveries in some branches of chemistry, i never gave much attention to the common routine of it, and know but little of the common processes. is not this a refreshing confession from the celebrated discoverer of oxygen? the casual reader would not credit such a statement from one who august , , introduced to the civilized world so important an element as oxygen. because he did not know the "common processes" of chemistry and had not concerned himself with the "common routine" of it, led to his blazing the way among chemical compounds in his own fashion. many times since the days of priestley real researchers after truth have proceeded without compass and uncovered most astonishing and remarkable results. they had the genuine research spirit and were driven forward by it. priestley knew little of the labyrinth of analysis and cared less; indeed, he possessed little beyond an insatiable desire to unfold nature's secrets. admiration for priestley increases on hearing him descant on the people about him--on the natives-- here every house-keeper has a garden, out of which he raises almost all he wants for his family. they all have cows, and many have horses, the keeping of which costs them little or nothing in the summer, for they ramble with bells on their necks in the woods, and come home at night. almost all the fresh meat they have is salted in the autumn, and a fish called _shads_ in the spring. this salt shad they eat at breakfast, with their tea and coffee, and also at night. we, however, have not yet laid aside our english customs, and having made great exertion to get fresh meat, it will soon come into general use. proudly must he have said-- my youngest son, harry, works as hard as any farmer in the country and is as attentive to his farm, though he is only eighteen.... two or three hours i always work in the fields along with my son.... and, then as a supplement, for it was resting heavily on his mind, he added-- what i chiefly attend to now is my church history ... but i make some experiments every day (july , ), and shall soon draw up a paper for the philosophical society at philadelphia. early in december of he entrusted a paper, intended for the american philosophical society to the keeping of dr. young, a gentleman from northumberland en route for europe. acquainting his friend lindsey of this fact, he took occasion to add-- i have much more to do in my laboratory, but i am under the necessity of shutting up for the winter, as the frost will make it impossible to keep my water fit for use, without such provision as i cannot make, till i get my own laboratory prepared on purpose, when i hope to be able to work alike, winter and summer. dr. young carried two papers to philadelphia. the first article treated of "experiments and observations relating to the analysis of atmospherical air," and the second "further experiments relating to the generation of air from water." they filled quarto pages of volume of the transactions of the american philosophical society. on reading them the thought lingers that these are the first contributions of the eminent philosopher from his american home. hence, without reference to their value, they are precious. they represent the results of inquiries performed under unusual surroundings. it is very probable that priestley's english correspondents desired him to concentrate his efforts upon experimental science. they were indeed pleased to be informed of his church history, and his vital interest in religion, but they cherished the hope that science would in largest measure displace these literary endeavors. priestley himself never admitted this, but must have penetrated their designs, and, recognizing the point of their urging, worked at much disadvantage to get the results presented in these two pioneer studies. present day students would grow impatient in their perusal, because of the persistent emphasis placed on phlogiston, dephlogisticated air, phlogisticated air, and so forth. in the very first paper, the opening lines show this: it is an essential part of the antiphlogistic theory, that in all the cases of what i have called _phlogistication_ of _air_, there is simply an absorption of the dephlogisticated air, or, as the advocates of that theory term it, the oxygen contained in it, leaving the _phlogisticated_ part, which they call _azote_, as it originally existed in the atmosphere. also, according to this system, _azote_ is a simple substance, at least not hitherto analyzed into any other. no matter how deeply one venerates priestley, or how great honor is ascribed to him, the question continues why the simpler french view was not adopted by this honest student. further, as an ardent admirer one asks why should priestley pen the next sentence: they, therefore, suppose that there is a determinate proportion between the quantities of oxygen, and azote in every portion of atmospherical air, and that all that has hitherto been done has been to separate them from one another. this proportion they state to be parts of oxygen and parts of azote, in of atmospherical air. priestley knew that there was a "determinate proportion." he was not, however, influenced by quantitative data. sir oliver lodge said[ ]-- priestley's experiments were admirable, but his perception of their theoretical relations was entirely inadequate and, as we now think, quite erroneous.... in theory he had no instinct for guessing right ... he may almost be said to have had a predilection for the wrong end. at present the french thought is so evident that it seems incomprehensible that priestley failed to grasp it, for he continues-- in every case of the diminution of atmospherical air in which this is the result, there appears to me to be something emitted from the substance, which the antiphlogistians suppose to act by simple absorption, and therefore that it is more probable that there is some substance, and the same that has been called _philogiston_, or the _principle of inflammability_ ... emitted, and that this phlogiston uniting with part of the dephlogisticated air forms with it part of the phlogisticated air, which is found after the process. subsequently ( ), he advised the society that he had executed other experiments which corroborated those outlined in his first two papers, adding-- had the publication of your _transactions_ been more frequent, i should with much pleasure have submitted to the society a full account of these and other experiments which appear to me to prove, that metals are compound substances, and that water has not yet been decomposed by any process that we are acquainted with. still, however, i would not be very positive, as the contrary is maintained by almost all the chemists of the age.... and thus he proceeds, ever doing interesting things, but blind to the patent results because he had phlogiston constantly before him. he looked everywhere for it, followed it blindly, and consequently overlooked the facts regarded as most significant by his opponents, which in the end led them to correct conclusions. the experimental results in the second paper also admit of an interpretation quite the opposite of that deduced by priestley. he confidently maintained that air was invariably generated from water, because he discovered it and liberated it from water which he was certain did not contain it in solution. he was conscientious in his inferences. deeply did his friends deplore his inability to see more than a single interpretation of his results! the papers were read before the american philosophical society on the th of february, . their author as they appear in print, is the rev. dr. j. priestley. it is doubtful whether he affixed this signature. more probable is it that the secretary of the society was responsible, and, because he thought of priestley in the rôle of a reverend gentleman rather than as a scientific investigator. here, perhaps, it may be mentioned that the first, the very first communication from priestley's pen to the venerable philosophical society, was read in . it was presented by a friend--a mr. w. vaughan, whose family in england were always the staunchest of priestley's supporters. and it is not too much to assume that it was the same influence which one year later ( ) brought about priestley's election to membership in the society, for he was one of " new members" chosen in january of that year. there are evidences of marked friendliness to priestley all about the hall of the society, for example his profile in plaster of paris, "particularly valuable for the resemblance" to the doctor, which was presented in ; a second "profile in black leather" given by robert patterson, a president of the society, and an oil portrait of him from mrs. dr. caspar wistar. his appearance in person, when for the first time he sat among his colleagues of the society, was on the evening of february , --the night upon which the two papers, commented upon in the last few paragraphs were presented, although he probably did not read them himself, this being done by a friend or by the secretary. sixteen members were present. among these were some whose names have become familiar elsewhere, such as barton, woodhouse and others. today, the presence in the same old hall of a renowned scientist, from beyond the seas, would literally attract crowds. then it was not the fashion. but probably he had come unannounced and unheralded. further, he was speaking at other hours on other topics in the city. it is not recorded that he spoke before the philosophers. perhaps he quietly absorbed their remarks and studied them, although he no doubt was agreeably aroused when mr. peale presented to the society a young son of four months and four days old, being the first child born in the philosophical hall, and requested that the society would give him a name. on which the society unanimously agreed that, after the name of the chief founder and late president of the society, he should be called franklin. in anticipation of any later allusion to priestley's sojourn in philadelphia be it observed that he attended meetings of the american philosophical society three times in , twice in , three times in and once in , and that on february rd, , he was chosen to deliver the annual oration before the society, but the committee reported that they waited on dr. priestley last monday afternoon, who received the information with great politeness, but declined accepting of the appointment. this lengthy digression must now be interrupted. it has gone almost too far, yet it was necessary in order that an account of the early experimental contributions of the exile might be introduced chronologically. as already remarked, americans are most deeply interested in everything priestley did during his life in this country and particularly in his scientific activities. on resuming the story of the routine at northumberland in the closing months of the year , there comes the cry from an agonized heart,-- we have lost poor harry! this was the message to a philadelphia resident--a friend from old england. the loss, for such it emphatically was, affected the doctor and mrs. priestley very deeply. this particular son was a pride to them and though only eighteen years old had conducted his farm as if he had been bred a farmer. he was uncommonly beloved by all that worked under him. his home was just outside of the borough of northumberland. it was the gift of his father. his interment in "a plot of ground" belonging to the society of friends is thus described by mr bakewell: i attended the funeral to the lonely spot, and there i saw the good old father perform the service over the grave of his son. it was an affecting sight, but he went through it with fortitude, and after praying, addressed the attendants in a few words, assuring them that though death had separated them here, they should meet again in another and a better life. the correspondence to friends in england was replete with accounts of lectures which were in process of preparation. they were discourses on the evidences of revelation and their author was most desirous of getting to philadelphia that he might there deliver them. at that time this city was full of atheism and agnosticism. then, too, the hope of establishing a unitarian church was ever in priestley's thoughts. how delightful it is to read, february th, -- i am now on my way to philadelphia. when he left it in he was rather critical of it, but now after three days he arrived there. it was a very good journey, accompanied by my daughter-in-law, in my son's yarmouth waggon, which by means of a seat constructed of straw, was very easy. yes, back again to the city which was the only city in this country ever visited by him. although at times he considered going to new york, and even to boston, philadelphia was to become his mecca. in it he was to meet the most congenial scientific spirits, and to the younger of these he was destined to impart a new inspiration for science, and for chemical science in particular. at the close of the three days' journey he wrote-- i am a guest with mr. russell.... we found him engaged to drink tea with president washington, where we accompanied him and spent two hours as in any private family. he (washington) invited me to come at any time, without ceremony. everything is the reverse of what it is with you. this was his first meeting with washington. the spirit of the occasion impressed him. the democratic behavior of the great federalist must have astonished him, if he ever entertained, as lord brougham would have us believe, a hostile opinion and thought him ungrateful because he would not consent to make america dependent upon france. priestley's eagerness to preach was intense, and happy must he have been on the day following his arrival, when his heart's wish was gratified. he preached in the church of mr. winchester-- to a very numerous, respectable, and very attentive audience. many were members of congress, and according to one witness-- the congregation that attended were so numerous that the house could not contain them, so that as many were obliged to stand as sit, and even the doorways were crowded with people. mr. vice-president adams was among the regular attendants. all this greatly encouraged the doctor. his expectations for the establishment of a unitarian congregation were most encouraging. he declared himself ready to officiate every winter without salary if he could lodge somewhere with a friend. the regular and punctual attendance of mr. adams pleased him so much that he resolved on printing his sermons, for they were in great demand, and to dedicate the same to the vice-president. he was also gratified to note that the "violent prejudice" to him was gradually being overcome. today we smile on recalling the reception accorded the good doctor in his early days in philadelphia. we smile and yet our hearts fail to understand just why he should have been so ostracised. to confirm this it may be noted that on one occasion priestley preached in a presbyterian chapel, very probably in northumberland, when one of the ministers was so displeased-- that he declared if they permitted him any more, he would never enter the puplit again. and in on coming the first time to philadelphia he wrote there is much jealousy and dread of me. how shameful and yet it was most real. bakewell narrates that "i went several times to the baptist meeting in second street, under the care of dr. rogers. this man burst out, and bade the people beware, for 'a priestley had entered the land;' and then, crouching down in a worshiping attitude, exclaimed, 'oh, lamb of god! how would they pluck thee from thy throne!'" the public prints flayed rogers, and even the staid old philosophical society indicated to him that such conduct ill became a member of that august body. accordingly humiliated he repented his error and in time became strongly attached to priestley, concerning whom he told this story to a mr. taylor whose language is here given: the doctor (priestley) would occasionally call on dr. rogers, and without any formal invitation, pass an evening at his house. one afternoon he was there when dr. rogers was not at home, having been assured by mrs. rogers that her husband would soon be there. meanwhile, mr. ----, a baptist minister, called on dr. rogers, and being a person of rough manners, mrs. rogers was a good deal concerned lest he should say something disrespectful to dr. priestley in case she introduced the doctor to him. at last, however, she ventured to announce dr. priestley's name, who put out his hand; but instead of taking it the other immediately drew himself back, saying, as if astonished to meet with dr. priestley in the home of one of his brethren, and afraid of being contaminated by having any social intercourse with him, 'dr. priestley! i can't be cordial.' it is easy to imagine that by this speech mrs. rogers was greatly embarrassed. dr. priestley, observing this, instantly relieved her by saying, and with all that benevolent expression of countenance and pleasantness of manner for which he was remarkable, 'well, well, madam, you and i can be cordial; and dr. rogers will soon be with us, mr. ---- and he can converse together, so that we shall all be very comfortable.' thus encouraged, mrs. rogers asked dr. priestley some questions relative to the scripture prophecies, to which he made suitable replies; and before dr. rogers arrived, mr. ---- was listening with much attention, sometimes making a remark or putting in a question. the evening was passed in the greatest harmony, with no inclination on the part of mr. ---- to terminate the conversation. at last dr. priestley, pulling out his watch, informed mr. ---- that as it was _ten_ o'clock it was time that two old men like them were at their quarters. the other at first was not willing to believe that dr. priestley's watch was accurate; but finding that it was correct, he took his leave with apparent regret, observing that he had never spent a shorter and more pleasant evening. he then went away, dr. priestley accompanying him, until it became necesary to separate. next morning he called on his friend, dr. rogers, when he made the following frank and manly declaration: 'you and i well know that dr. priestley is quite wrong in regard to his theology, but notwithstanding this, he is a great and good man, and i behaved to him at our first coming together like a fool and a brute.' many additional evidences might be introduced showing that the doctor was slowly winning his way among the people. it must also be remembered that not all of his associates were of the clerical group but that he had hosts of scientists as sincere and warm supporters. in woodhouse's laboratory he was ever welcome and there must have met many congenial spirits who never discussed politics or religion. this was after the manner of the lunar society in birmingham in which representatives of almost every creed came together to think of scientific matters. hence, it is quite probable that priestley's visit to philadelphia was on the whole full of pleasure. he was also in habits of close intimacy with dr. ewing, provost of the university of pennsylvania, and with the vice-provost, dr. john andrews, as well as with dr. benjamin rush who had long been his friend and with whom he corresponded at frequent intervals after his arrival in america. to him priestley had confided his hope of getting a college in northumberland and inquired,-- would the state give any encouragement to it? to rush he also wrote excusing my weakness (for such you will consider it) when, after giving you reason to expect that i would accept the professorship of chemistry, if it was offered to me, i now inform you that i must decline it. now and then he also advised him of such experiments as he was able to do; for example-- i made trial of the air of northumberland by the test of nitrous air, but found it not sensibly different from that of england. in the leisure he enjoyed his figure was often seen in congress. he relished the debates which at the time were on the treaty with england. he declared he heard as good speaking there as in the house of commons. he observed-- a mr. amos speaks as well as mr. burke; but in general the speakers are more argumentative, and less rhetorical. and whereas there are with you not more than ten or a dozen tolerable speakers, here every member is capable of speaking. while none of the letters to priestley's friends mention a family event of some importance the _american advertiser_, february , , announced that mr. william priestley, second son of the celebrated dr. joseph priestley, was married to the agreeable miss peggy foulke, a young lady possessed with every quality to render the marriage state happy. this occurred very probably just before the doctor set forth from northumberland to make his first philadelphia visit. it is singular that little is said of the son william by the doctor. could it be that, in some way, he may have offended his parent? in his _memorial_ rush, writing in the month of march, , noted: saw dr. priestley often this month. attended him in a severe pleurisy. he once in his sickness spoke of his second son, william, and wept very much. busy as he was in spreading his religious tenets, in fraternizing with congenial scientific friends, his thoughts would involuntarily turn back to england: here, though i am as happy as this country can make me ... i do not feel as i did in england. by may, , he had finished his discourses, although he proposed concluding with one emphatically unitarian in character. this was expected by his audience, which had been quietly prepared for it and received it with open minds and much approval. on his return to northumberland he promptly resumed his work on the "church history," but was much disturbed because of the failure of his correspondents in writing him regularly, so he became particularly active in addressing them. but better still he punctuated his composition of sermons, the gradual unfolding of his church history, and religious and literary studies in general, with experimental diversions, beginning with the publication ( ) of an octavo brochure of pages from the press of dobson in philadelphia, in which he addressed himself more especially to berthollet, de la place, monge, morveau, fourcroy and others on "considerations on the doctrine of phlogiston and the decomposition of water." it is the old story in a newer dress. its purpose was to bring home to americans afresh his particular ideas. the reviewer of the _medical repository_ staff was evidently impressed by it, for he said: it must give pleasure to every philosophical mind to find the united states becoming the theatre of such interesting discussion, and then adds that the evidence which was weighty enough to turn such men as black and others from the phlogiston idea to that of lavoisier-- has never yet appeared to dr. priestley considerable enough to influence his judgment, or gain his assent. priestley, as frequently observed, entertained grave doubts in regard to the constitution of metals. he thought they were "compounded" of a certain earth, or calx, and phlogiston. further he believed that when the phlogiston flew away, "the splendour, malleability, and ductility" of the metal disappeared with it, leaving behind a calx. again, he contended that when metals dissolved in acids the liberated "inflammable air" (hydrogen) did not come from the 'decompounded water' but from the phlogiston emitted by the metal. also, on the matter of the composition and decomposition of water, he held very opposite ideas. the french school maintained "that hydrogenous and oxygenous airs, incorporated by drawing through them the electrical spark turn to _water_," but priestley contended that "they combine into _smoking nitrous acid_." and thus the discussion proceeded, to be answered most intelligently, in , by adet,[ ] whose arguments are familiar to all chemists and need not therefore be here repeated. of more interest was the publication of two lectures on combustion by maclean of princeton. they filled a pamphlet of pages. it appeared in , and was, in brief, a refutation of priestley's presentations, and was heartily welcomed as evidence of the "growing taste in america for this kind of inquiry." among other things maclean said of the various ideas regarding combustion--"becker's is incomplete, stahl's though ingenious, is defective; the antiphlogistic is simple, consistent and sufficient, while priestley's resembling stahl's but in name, is complicated, contradictory and inadequate." not all american chemists were ready to side track the explanations of priestley. the distinguished dr. mitchill wrote priestley on what he designated "an attempt to accommodate the disputes among chemists concerning phlogiston." this was in november, . it is an ingenious effort which elicited from priestley ( ) his sincere thanks, and the expressed fear that his labours "will be in vain." and so it proved. present day chemists would acquiesce in this statement after reading mitchill's "middle-of-the-road" arguments. they were not satisfactory to maclean and irritated priestley. in june a second letter was written by priestley to mitchill. in it he emphasized the substitution of zinc for "finery cinder." from it he contended inflammable air could be easily procured, and laid great stress on the fact that the "inflammable air" came from the metal and not from the water. he wondered why berthollet and maclean had not answered his first article. to this, a few days later, mitchill replied that he felt there was confusion in terms and that the language employed by the various writers had introduced that confusion; then for philological reasons and to clarify thoughts mitchill proposed to strike out _azote_ from the nomenclature of the day and take _septon_ in its place; he also wished to expunge hydrogene and substitute phlogiston. he admitted that priestley's experiments on zinc were difficult to explain by the antiphlogistic doctrine, adding-- it would give me great satisfaction that we could settle the points of variance on this subject; though, even as it is, i am flattered by your (priestley's) allowing my attempt 'to reconcile the two theories to be ingenious, plausible and well-meant.... your idea of carrying on a philosophical discussion in an amicable manner is charming'.... but the peace-maker was handling a delicate problem. he recognized this, but desired that the pioneer studies, then in progress might escape harsh polemics. this was difficult of realization for less than a month later fuel was added to the fire by maclean, when in writing mitchill, who had sent him priestley's printed letter, he emphatically declared that the experiment with the zinc does not seem to be of more consequence than that with the iron and admits of an easy explanation on antiphlogistic principles. and he further insisted that the experiments of priestley proved water to be composed "of hydrogene and oxygene." four days later (july , ) priestley wrote mitchill that he had replaced zinc by red precipitate and did not get water on decomposing inflammable air with the precipitate. again, august , , he related to mitchill that the modern doctrine of water consisting of _oxygene_ and _hydrogene_ is not well founded ... water is the basis of all kinds of air, and without it no kind of air can be produced ... not withstanding the great use that the french chemists make of scales and weights, they do not pretend to weigh either their _calorique_ or _light_; and why may not _phlogiston_ escape their researches, when they employ the same instruments in that investigation? there were in all eight letters sent by priestley to mitchill. they continued until february, . their one subject was phlogiston and its rôle in very simple chemical operations. the observations were the consequence of original and recent experiments, to which i have given a good part of the leisure of the last summer; and i do not propose to do more on the subject till i hear from the great authors of the theory that i combat in america; but adds,-- i am glad ... to find several advocates of the system in this country, and some of them, i am confident, will do themselves honour by their candour, as well as by their ability. this very probably was said as a consequence of the spirited reply james woodhouse[ ] made to the papers of maclean. as known, woodhouse worked unceasingly to overthrow the doctrine of phlogiston, but was evidently irritated by maclean, whom he reminds-- you are not yet, doctor, the conqueror of this veteran in philosophy. this was a singularly magnanimous speech on woodhouse's part, for he had been hurling sledgehammer blows without rest at the structure priestley thought he had reared about phlogiston and which, he believed, most unassailable, so when in (july) priestley began his reply to his "antiphlogistian opponents" he took occasion to remark: i am happy to find in dr. woodhouse one who is equally ingenious and candid; so that i do not think the cause he has undertaken will soon find a more able champion, and i do not regret the absence of m. berthollet in egypt. noble words these for his young adversary who, in consequence of strenuous laboratory work, had acquired a deep respect and admiration for priestley's achievements, though he considered he had gone far astray. the various new, confirmatory ideas put forth by priestley need not be here enumerated. they served their day. dr. mitchill evidently enjoyed this controversial chemical material, for he wrote that he hoped the readers of the _medical repository_, in which the several papers appeared, would participate the pleasure we feel on taking a retrospect of our pages, and finding the united states the theatre of so much scientific disquisition. and yet, when in , a pamphlet of pages bearing the title "the doctrine of phlogiston established, etc." appeared there was consternation in the ranks of american chemists. woodhouse was aroused. he absolutely refuted every point in it experimentally, and dr. mitchill avowed-- we decline entering into a minute examination of his experiments, as few of his recitals of them are free from the _triune_ mystery of phlogiston, which exceeds the utmost stretch of our faith; for according to it, _carbon is phlogiston_, and _hydrogen is phlogiston_, and _azote is phlogiston_; and yet there are not _three_ phlogistons, but _one_ phlogiston! it was imperative to submit the preceding paragraphs on chemical topics, notwithstanding they have, in a manner, interrupted the chronological arrangement of the activities of the doctor in his home life. they were, it is true, a part of that life--a part that every chemist will note with interest and pleasure. they mean that he was not indifferent to chemistry, and that it is not to be supposed that he ever could be, especially as his visits to philadelphia brought to his attention problems which he would never suffer to go unanswered or unsolved because of his interest in so many other things quite foreign to them. however, a backward look may be taken before resuming the story of his experimental studies. it has already been said that the non-appearance of letters caused him anxiety. for instance he wrote lindsey, july , -- it is now four months since i have received any letter from you, and it gives me most serious concern. but finally the longed-for epistle arrived and he became content, rejoicing in being able to return the news-- i do not know that i have more satisfaction from anything i ever did, than from the lay unitarian congregation i have been the means of establishing in philadelphia. for the use of this group of worshipers he had engaged the common hall in the college (university of pennsylvania). but amidst this unceasing activity of body and mind--very evidently extremely happy in his surroundings--he was again crushed to earth by the death of his noble wife-- always caring for others and never for herself. this occurred nine months after the departure of harry. it was a fearful blow. for more than thirty-four years they had lived most happily together. the following tribute, full of deep feeling and esteem attests this-- my wife being a woman of an excellent understanding much improved by reading, of great fortitude and strength of mind, and of a temper in the highest degree affectionate and generous.... also excelling in everything relating to household affairs, she entirely relieved me of all concern of that kind, which allowed me to give all my time to the prosecution of my studies. she was not only a true helpmate--courageous and devoted--but certainly most desirous that the husband in whom she absolutely believed should have nothing to interrupt or arrest the pursuits dear to him and in which she herself must have taken great but quiet pride, for she was extremely intelligent and original. madam belloc has mentioned it is a tradition in the family that mrs. priestley once sent her famous husband to market with a large basket and that he so acquitted himself that she never sent him again! the new house, partly planned by her, at the moment well advanced and to her fancy, was not to be her home for which she had fondly dreamed. priestley was deeply depressed but his habitual submission carried him through, although all this is pathetically concealed in his letters. there were rumours flitting about that priestley purposed returning to england. that his friends might be apprised of his real intentions the following letter was permitted to find its way into the newspapers: northumberland oct. , my dear sir, every account i have from england makes me think myself happy in this peaceful retirement, where i enjoy almost everything i can wish in this life, and where i hope to close it, though i find it is reported, both here and in england that i am about to return. the two heavy afflictions i have met with here, in the death of a son, and of my wife, rather serve to attract me to the place. though dead and buried, i would not willingly leave them, and hope to rest with them, when the sovereign disposer of all things shall put a period to my present labours and pursuits. the advantages we enjoy in this country are indeed very great. here we have no poor; we never see a beggar, nor is there a family in want. we have no church establishment, and hardly any taxes. this particular state pays all its officers from a treasure in the public funds. there are very few crimes committed and we travel without the least apprehension of danger. the press is perfectly free, and i hope we shall always keep out of war. i do not think there ever was any country in a state of such rapid improvement as this at present; but we have not the same advantages for literary and philosophical pursuits that you have in europe, though even in this respect we are every day getting better. many books are now printed here, but what scholars chiefly want are old books, and these are not to be had. we hope, however, that the troubles of europe will be the cause of sending us some libraries and they say that it is an ill wind that blows no profit. i sincerely wish, however, that your troubles were at an end, and from our last accounts we think there must be a peace, at least from the impossibility of carrying on the war. with every good wish to my country and to yourself, i am, dear sir, yours sincerely, j. priestley. gradually the news went forth that the doctor contemplated a second visit to the metropolis--philadelphia, the capital of the young republic. he wrote-- having now one tie, and that a strong one, to this place (northumberland) less than i have had i propose to spend more time in philadelphia. as long as he was capable of public speaking it was his desire to carry forward his missionary work, but the loss of my fore teeth (having now only two in the upper jaw) together with my tendency to stammering, which troubles me sometimes, is much against me. accordingly in early january of he might have been found there. he alludes in his correspondence to the presence in the city of c. volney, a french philosopher and historian, who had been imprisoned but regained liberty on the overthrow of robespierre when he became professor of history in the _ecole normal_. volney was not particularly pleased with priestley's discourses, and took occasion some weeks later to issue volney's answer to priestley which was advertised by the _aurora_ as on sale by the principal booksellers, price cents. he was exceedingly rejoiced at the flourishing state of the unitarian society and the manner in which its services were conducted. on the occasion of his first discourse the english ambassador, mr. lister, was in the audience and priestley dined with him the day following. friends had prevailed upon priestley to preach a charity sermon on his next sunday, in one of the episcopal churches, but in the end it was "delivered at the university hall." his mind was much occupied with plans for controverting infidelity, the progress of which here is independent of all reasoning,-- so he published the third edition of his "observations on the increase of infidelity" and an "outline of the evidences of revealed religion." in the first of them he issued a challenge to volney who was much looked up to by unbelievers here. volney's only reply was that he would not read the pamphlet. it was in these days that priestley saw a great deal of thomas jefferson; indeed, the latter attended several of his sermons. the intercourse of these friends was extremely valuable to both. jefferson welcomed everything which priestley did in science and consulted him much on problems of education. at the election in the american philosophical society in the closing days of there was openly discussed whether to choose me (priestley) or mr. jefferson, president of the society,-- which prompted the doctor to give his informant good reasons why they should not choose _me_. naturally he listened to the political talk. he worried over the apparent dislike observed generally to france. he remarked the rich not only wish for alliance offensive and defensive with england ... but would have little objection to the former dependence upon it, and the disposition of the lower orders of the people ... for the french ... is not extinguished. he was much annoyed by peter porcupine. the latter was publishing a daily paper ( ) and in it frequently brought forward priestley's name in the most opprobrious manner, although priestley in his own words-- had nothing to do with the politics of the country. the doctor advised friend lindsey that he (porcupine) every day, advertizes his pamphlet against me, and after my name adds, "commonly known by the name of the fire-brand philosopher." however, he flattered himself that he would soon be back in northumberland, where he would be usefully engaged, as i have cut myself out work for a year at least ... besides attending to my experiments. mr. adams had come into the presidency, so priestley very properly went to pay his respects and take leave of the late president (washington) whom he thought in not very good spirits, although he invited me to mount vernon and said he thought he should hardly go from home twenty miles as long as he lived. priestley's fame was rapidly spreading through the land. thoughtful men were doing him honor in many sections of the country, as is evident from the following clipping from a portland (me.) paper for march , :-- on friday the twenty-fourth a number of gentlemen, entertaining a high sense of the character, abilities and services of the reverend doctor joseph priestley, as a friend and promoter of true science dined together at the columbian tavern, in commemoration of his birth. the following toasts were given. . that illustrious christian and philosopher, joseph priestley: may the world be as grateful to him for his services as his services are beneficial to the world. . may the names of locke, newton, montesquieu, hartley and franklin be had in everlasting remembrance. . the great gift of god to man, reason! may it influence the world in policy, in laws, and in religion. . truth: may the splendour of her charms dissipate the gloom of superstition, and expel hypocricy from the heart of man. . may our laws be supported by religion: but may religion never be supported by law. . white-robed charity: may she accompany us in all our steps and cover us with a mantle of love. . christians of all denominations: may they "love one another." as it was a "feast of reason" the purest philanthrophy dignified the conversation; and moderation and temperance bounded every effusion of the heart. it was in the summer of that he carried forward his work on phlogiston, alluded to on p. . he understood quite well that the entire chemical world was against him but he was not able to find good reasons to despair of the old system. it must be remembered that in these days, also, he had thomas cooper with him. with this gentleman he discussed his scientific studies and with him also he carried on many arguments upon the burning subject of infidelity, about which he continuously wrote his friends in this country and in england. it was quite generally believed that cooper was an infidel. never, however, did their intimacy suffer in the slightest by their conflicting views. the _church history_ continued to hold priestley's first thought. he was a busy student, occupied with a diversity of interests and usually cheerful and eager to follow up new lines of endeavor. the arrival of vessels from the home country was closely watched. books and apparatus were brought by them. while, as observed, he was singularly cheerful and happy, he confessed at times that my character as a philosopher is under a cloud. yet, this was but a momentary depression, for he uttered in almost the same breath-- everything will be cleared up in a reasonable time. amid the constant daily duties he found real solace in his scientific pursuits; indeed when he was quite prepared to abandon all his activities he declared of his experiments that he could not stop them for i consider them as that study of the works of the great creator, which i shall resume with more advantage hereafter. he advised his friends lindsey and belsham-- i cannot express what _i_ feel on receiving your letters. they set my thoughts afloat, so that i can do nothing but ruminate a long time; but it is a most pleasing melancholy. far removed from european events he was nevertheless ever keen and alert concerning them. then the winter of appears to have been very severe. his enforced confinement to home probably gave rise to an introspection, and a slight disappointment in matters which had formerly given him pleasure. for example, he puzzled over the fact that on his second visit to philadelphia, mr. adams was present but once at his lectures, and remarks-- when my lectures were less popular, and he was near his presidentship, he left me, making a kind of apology, from the members of the principal presbyterian church having offered him a pew there. he seemed to interest himself in my favour against m. volney, but did not subscribe to my church history ... i suppose he was not pleased that i did not adopt his dislike of the french. when january of arrived his joy was great. a box of books had come. among them was a general dictionary which he regarded as a real treasure. reading was now his principal occupation. he found the making of many experiments irksome and seemed, all at once, "quite averse to having his hands so much in water." presumably these were innocent excuses for his devotion to the church history which had been brought up to date. furthermore he was actually contemplating transplanting himself to france. but with it all he wrote assiduously on religious topics, and was highly pleased with the experimental work he had sent to dr. mitchill (p. ). he advised his friends of the "intercepted letters" which did him much harm when they were published. they called down upon him severest judgement and suspicion, and made him-- disliked by all the friends of the ruling power in this country. it may be well to note that these "intercepted letters" were found on a danish ship, inclosed in a cover addressed to dr. priestley, in america they came from friends, english and french, living in paris. they abounded with matter of the most serious reflection.... if the animosity of these apostate englishmen against their own country, their conviction that no submissions will avert our danger, and their description of the engines employed by the directory for our destruction, were impressed as they ought to be, upon the minds of all our countrymen, we should certainly never again be told of the innocent designs of these traitors, or their associates-- the preceding quotation is from a booklet containing exact copies of the "intercepted letters." in the first of the letters, dated feb. , , the correspondent of priestley tells that he had met a young frenchman who had visited northumberland and we all rejoiced at the aggreeable information that at the peace you would not fail to revisit europe; and that he hoped you would fix yourself in this country (france). whether you fix yourself here or in england, (_as england will then be_) is probably a matter of little importance ... but we all think you are misplaced where you are, though, no doubt, in the way of _usefulness_-- the editor of the letters annotates _usefulness_ thus: dr. priestley is _in the way of usefulness_ in america, because he is labouring there, as his associates are in europe, to disunite the people from their government, and to introduce the blessings of french anarchy. these "intercepted letters" in no way prove that dr. priestley was engaged in any movement against his native land or against his adopted country. however, the whole world was in an uproar. people were ready to believe the worst regarding their fellows, so it is not surprising that he should have declared himself "disliked." he alludes frequently to the marvelous changes taking place in the states. everything was in rapid motion. taxes were the topic of conversation on all sides. to divert his philosophizing he busied himself in his laboratory where many "original experiments were made." he avoided the crowd. there was too great a party spirit. indeed, there was violence, so he determined not to visit philadelphia. he sought to escape the "rancorous abuse" which was being hurled at him-- as a citizen of france. one must read his correspondence to fully appreciate priestley during the early days of . what must have been his mental condition when he wrote lindsey-- as to a public violent death the idea of that does not affect me near so much and i cannot express what i feel when i receive and read your letters. i generally shed many tears over them. there was no assurance in financial and commercial circles. the hopes of neither the more sober, nor of the wild and fanatic reformers of humanity could be realized, and they got into such a war of hate and abuse that they themselves stamped their doctrines false. priestley was out of patience with the public measures of the country. he disliked them as much as he did those of england, but added here the excellence of the constitution provides a remedy, if the people will make use of it, and if not, they deserve what they suffer. the constitution was a favorite instrument with him. a most interesting lecture upon it will be found among the _discourses_ which he proposed delivering in philadelphia. this never occurred. the academy he expected to see in operation failed for support. the walls were raised and he feared it would go no further. the legislature had voted it $ , but the senate negatived this act. he thought of giving up the presidency of it. he wrote dr. rush that he was quite busy with replies to dr. woodhouse's attack on his confirmation of the existence of phlogiston, (p. ). he relished his discussions with woodhouse and was confident that eventually he would "overturn the french system of chemistry." he further remarked to rush-- were you at liberty to make an excursion as far as these _back woods_ i shall be happy to see you, and so would many others. but at that particular moment rush was too much engaged in combating yellow fever, which again ravaged philadelphia, and all who could, fled, and the streets were "lifeless and dead." the prevalence of this fearful plague was a potent factor in priestley's failure to visit the city during the year--the last year of a closing century which did not end in the prosperity anticipated for it in the hopeful months and years following the war. it seemed, in many ways, to be the end of an era. washington died december , , and the federalists' tenure of power was coming to a close. the jeffersonians, aided by eight of the electoral votes of pennsylvania, won the victory, amid outbursts of unprecedented political bitterness. it was, therefore, very wise that the doctor remained quietly at home in northumberland with his experiments and church history. the new century--the th--found our beloved philosopher at times quite proud of the success he had with his experiments and full of genuine hope that "phlogiston" was established; and again dejected because of the "coarse and low articles" directed against him by the prints of the day. to offset, in a measure, the distrust entertained for him because of the "intercepted letters" he addressed a series of _letters_ to the inhabitants of northumberland and vicinity. these were explanatory of his views. at home they were most satisfying but in the city they brought upon him "more abuse." and, so, he translated a passage from petrarch which read-- by civil fueds exiled my native home, resign'd, though injured, hither i have come. here, groves and streams, delights of rural ease; yet, where the associates, wont to serve and please; the aspect bland, that bade the heart confide? absent from these, e'en here, no joys abide. and these were incorporated in his brochure. having alluded to the _letters_ addressed to the northumberland folks, it may be proper to introduce a letter which priestley received from mr. jefferson, whom the former was disposed to hold as "in many respects the first man in this country:" philadelphia, jan. , . dear sir-- i thank you for the pamphlets (letters) you were so kind as to send me. you will know what i thought of them by my having before sent a dozen sets to virginia, to distribute among my friends; yet i thank you not the less for these, which i value the more as they came from yourself. the papers of political arithmetic, both in yours and mr. cooper's pamphlets, are the most precious gifts that can be made to us; for we are running navigation-mad, and commerce-mad, and navy-mad, which is worst of all. how desirable it is that you should pursue that subject for us. from the porcupines of our country you will receive no thanks, but the great mass of our nation will edify, and thank you. how deeply have i been chagrined and mortified at the persecutions which fanaticism and monarchy have excited against you, even here! at first, i believed it was merely a continuance of the english persecution; but i observe that, on the demise of porcupine, and the division of his inheritance between fenno and brown, the latter (though succeeding only to the federal portion of porcupinism, not the anglican, which is fenno's part) serves up for the palate of his sect dishes of abuse against you as high-seasoned as porcupine's were. you have sinned against church and king, and therefore can never be forgiven. how sincerely i have regretted that your friend, before he fixed a choice of position, did not visit the valleys on each side of the blue range in virginia, as mr. madison and myself so much wished. you would have found there equal soil, the finest climate, and the most healthy air on the earth, the homage of universal reverence and love, and the power of the country spread over you as a shield; but, since you would not make it your country by adoption, you must now do it by your good offices. mr. livingston, the chancellor of new york, so approved the "letters" that he got a new edition of them printed at albany. the following letter to this same gentleman, although upon another subject than the "letters" is not devoid of interest. it has come into the writer's hands through the kind offices of dr. thomas l. montgomery, state librarian of pennsylvania: sir, i think myself much honoured by your letter, and should have thought myself singularly happy if my situation had been near to such a person as you. persons engaged in scientific pursuits are few in this country. indeed, they are not very numerous anywhere. in other respects i think myself very happy where i am. i have never given much attention to machines of any kind, and therefore cannot pretend to decide concerning your proposal for the improvement of the fire engine. it appears to me to deserve attention. but i do not for want of a drawing see in what manner the steam is to be let into the cylinder, or discharged from it. there would be, i fear, an objection to it from the force necessary to raise the column of mercury, and from the evaporation of the mercury in the requisite heat. i have found that it loses weight in ° fahrenheit. if the mercury was pure, i should not apprehend much from the calcination of it, though, as i have observed, the agitation of it in water, converts a part of it into a black powder, which i propose to examine farther. if travelling was attended with no fewer inconveniences here than it is in england, i should certainly wait upon you and some other friends at new york. but this, and my age, render it impossible, and it would be unreasonable to expect many visitors in this _back woods_. i shall be very happy to be favoured with your correspondence, and am, sir, yours sincerely, j. priestley northumberland april , . in this period thomas cooper was convicted of libel. he was thrown into prison. priestley regarded him as a rising man in the country.[ ] he said the act was the last blow of the federal party "which is now broke up." priestley's daughter, in england, was ill at this time. her life was despaired of and tidings from her were few and most distressing, but the doctor maintained a quiet and calm assurance of her recovery. subsequent correspondence between mr. jefferson and priestley had much in it about the new college which the former contemplated for the state of virginia. indeed, the thought was entertained that priestley himself might become a professor in it, but his advanced age, he contended forbade this, although he was agreeable to the idea of getting professors from europe. here, perhaps, may well be included several letters, now in possession of the library of congress, which reveal the attitude of dr. priestley toward president jefferson, who was indeed most friendly to him: dear sir-- i am flattered by your thinking so favourably of my _pamphlets_, which were only calculated to give some satisfaction to my suspicious neighbours. chancellor livingston informs me that he has got an edition of them printed at albany, for the information of the people in the back country, where, he says, it is so much wanted. indeed, it seems extraordinary, that in such a country as this, where there is no court to dazzle men's eyes a maxim as plain as that and make should not be understood, and acted upon. it is evident that the bulk of mankind are governed by something very different from reasoning and argument. this principle must have its influence even in your congress, for if the members are not convinced by the excellent speeches of mr. gallatin and nicolas, neither would they be persuaded tho one should rise from the dead. it is true that i had more to do with colleges, and places of education, than most men in europe; but i would not pretend to advise in this country. i will, however, at my leisure, propose such _hints_ as shall occur to me; and if you want tutors from england, i can recommend some very good ones. were i a few years younger, and more moveable, i should make interest for some appointment in your institution myself; but age and inactivity are fast approaching, and i am so fixed here, that a remove is absolutely impossible, unless you were possessed of _aladin's lamp_, and could transport my house, library, and laboratory, into virginia without trouble or expense. on my settlement here the gentlemen in the neighbourhood, thinking to make me of some use, set on foot a college, of which i gave them the plan, and they got it incorporated, and made me the president; but tho i proposed to give lectures _gratis_, and had the disposal of a valuable library at the decease of a learned friend (new, near so), and had it in my power to render them important service in various ways, yet, owing i suspect, in part at least, to religious and political prejudices, nothing more has been done, besides marking the site of a building these five years, so that i have told them i shall resign. i much wish to have some conversation with you on social subjects; but i cannot expect that the vice president of the united states should visit me in my _shed_ at northumberland, and i cannot come to you. i intended on my settling here to have spent a month or so every winter at philadelphia, but the state of the times, and various accidents, have a little deranged my finances, and i prefer to spend what i can spare on my experiments, and publication, rather than in travelling and seeing my friends. with the greatest respect, i am, dear sir, yours sincerely, j. priestley. northumberland jan. , . dear sir-- i enclose my thoughts on the subject you did me the honour to propose to me. your own better judgment will decide concerning their value, or their fitness for the circumstances of your college. this may require a very different distribution of the business from that which i here recommend. i thank you for your care to transmit a copy of my works to bp. madison. he, as well as many others, speaks of the increasing spread of republican principles in this country. i wish i could see the effects of it. but i fear we flatter ourselves, and if i be rightly informed, my poor _letters_ have done more harm than good. i can only say that i am a sincere well wisher to this country, and the purity and stability of its constitution. yours sincerely, j. priestley. northumberland may , . hints concerning public education persons educated at public seminaries are of two classes. one is that of professional men, and physicians and divines who are to be qualified for entering upon their professions immediately after leaving the college or university. the other is that of gentlemen, and those who are designed for offices of civil and active life. the former must be minutely instructed in everything adding to their several professions, whereas to the latter a general knowledge of the several branches of science is sufficient. to the former, especially that of medicine, several professors are necessary, as the business must be subdivided, in order to be taught to advantage. for the purpose of the latter fewer professors are wanted, as it is most advisable to give them only the elements of the several branches of knowledge, to which they may afterwards give more particular attention, as they may have a disposition or convenience for it. lawyers are not supposed to be qualified for entering upon their professions at any place of public education. they are therefore to be considered as gentlemen to whom a general knowledge is sufficient. it is advisable, however, that when any subject, as that of medicine, is much divided, and distributed among a number of professors, lectures of a more general and popular nature be provided for the other classes of students, to whom some knowledge of the subject may be very useful. a general knowledge, for example, of anatomy and of medicine, too, is useful to all persons, and therefore ought not to be omitted in any scheme of liberal education. and if in a regular school of medicine any of the professors would undertake this, it might serve as an useful introduction to that more particular and accurate knowledge which is necessary for practiced physicians. the branches of knowledge which are necessary to the teachers of religion are not so many, or so distinct from each other, but that they may all be taught by one professor, as far as is necessary to qualify persons for commencing preachers. to acquire more knowledge, as that of the scriptures, ecclesistical history, etc. must be the business of their future lives. but every person liberally educated should have a general knowledge of metaphysics, the theory of morals, and religion; and therefore some popular lectures of this kind should be provided for the students in general. one professor of antient languages may be sufficient for a place of liberal education, and i would not make any provision for instruction in the modern languages, for tho the knowledge of them, as well as skill in fencing, dancing and riding, is proper for gentlemen liberally educated, instruction in them may be procured on reasonable terms without burdening the funds of the seminary with them. abstract mathematics, and natural philosophy, are so distinct, that they require different teachers. one is sufficient for the former, but the latter must be subdivided, one for natural history, another for experimental philosophy in general and a third for chemistry; in consequence of the great extension of this branch of experimental philosophy of late years. the botany, mineralogy, and other branches of natural history are sufficiently distinct to admit of different professors, nothing more than a general knowledge of each of them, and directions for acquiring a more extended knowledge of them is necessary at any place of education. two or three schools of medicine i should think sufficient for all the united states for some years to come, but with respect to these i do not pretend to give any opinion not having sufficient knowledge of the subject. places of liberal education in general should be made more numerous, and for each of them i should think the following professors (if the funds of the society will admit of it) should be engaged, _viz._ ( ) for the antient languages. ( ) the belles lettres, including universal grammar, oratory, criticism and bibliography. ( ) mathematics. ( ) natural history. ( ) experimental philosophy. ( ) chemistry, including the theory of agriculture. ( ) anatomy and medicine. ( ) geography and history, law, and general policy. ( ) metaphysics, morals, and theology. a course of liberal education should be as comprehensive as possible. for this purpose a large and well chosen _library_ will be of great use. not that the students should be encouraged to read books while they are under tuition, but an opportunity of seeing books, and looking into them, will give them a better idea of the value of them than they could get by merely hearing of them, and they would afterwards better know what books to purchase when they should have the means and the leisure for the perusal of them. a large collection of books will also be useful to the lecturer in _bibliography_ and would recommend the seminary to the professors in general, and make it a desirable place of residence for gentlemen of a studious turn. . in order to engage able professors, some fixed salaries are necessary; but they should not be much more than a bare subsistence. they will then have a motive to exert themselves, and by the fees of students their emoluments may be ample. the professorships in the english universities, which are largely endowed, are sinecures; while those in scotland, to which small stipends are annexed, are filled by able and active men. . it is not wise to engage any persons who are much advanced in life, or of established reputation for efficient teachers. they will not be so active as younger men who have a character to acquire. they will also better accommodate their lectures to the increasing light of the age, whereas old men will be attached to old systems, tho ever so imperfect. besides, they are the most expert in teaching who have lately learned, and the minutae of science, which are necessary to a teacher, are generally forgotten by good scholars who are advanced in life, and it is peculiarly irksome to relearn them. . i would not without necessity have recourse to any foreign country for professors. they will expect too much deference, and the natives will be jealous of them. . three things must be attended to in the education of youth. they must be _taught_, _fed_ and _governed_ and each of these requires very different qualifications. they who are the best qualified to teach are often the most unfit to govern, and it is generally advisable that neither of these have anything to do with providing victuals. in the english universities all these affairs are perfectly distinct. the _tutors_ only teach, the _proctors_ superintend the discipline, and the _cooks_ provide the victuals. philadelphia, apr. , . dear sir-- your kind letter, which, considering the numerous engagements incident to your situation, i had no right to expect, was highly gratifying to me, and i take the first opportunity of acknowledging it. for tho i believe i am completely recovered from my late illness, i am advised to write as little as possible. your invitation to pay you a visit is flattering to me in the highest degree, and i shall not wholly despair of some time or other availing myself of it, but for the present i must take the nearest way home. your resentment of the treatment i have met with in this country is truly generous, but i must have been but little impressed with the principles of the religion you so justly commend, if they had not enabled me to bear much more than i have yet suffered. do not suppose that, after the much worse treatment to which i was for many years exposed in england (of which the pamphlet i take the liberty to inclose will give you some idea) i was much affected by this. my _letters to the inhabitants of northumberland_ were not occasioned by any such thing, tho it served me as a pretense for writing them, but the threatenings of mr. pickering, whose purpose to send me out of the country mr. adams (as i conclude from a circuitous attempt that he made to prevent it) would not, in the circumstances in which he then was, have been able to directly oppose. my publication was of service to me in that and other respects and i hope, in some measure, to the common cause. but had it not been for the extreme absurdity and violence of the late administration, i do not know how far the measures might not have been carried. i rejoice more than i can express in the glorious reverse that has taken place, and which has secured your election. this i flatter myself will be the permanent establishment of truly republican principles in this country, and also contribute to the same desirable event in more distant ones. i beg you would not trouble yourself with any answer to this. the knowledge of your good opinion and good wishes, is quite sufficient for me. i feel for the difficulties of your situation, but your spirit and prudence will carry you thro them, tho not without paying the tax which the wise laws of nature have imposed upon preeminence and celebrity of every kind, a tax which, for want of true greatness of mind, neither of your predecessors, if i estimate their characters aright, paid without much reluctance. with every good wish, i am, dear sir, yours sincerely, j. priestley. p.s. as i trust that _politics_ will not make you forget what is due to _science_, i shall send you a copy of some articles that are just printed for the _transactions of the philosophical society_ in this place. no. ( ) p. is the most deserving of your notice. i should have sent you my _defence of phlogiston_, but that i presume you have seen it. june, . to thomas jefferson, president of the united states of america. sir, my high respect for your character, as a politician, and a man, makes me desirous of connecting my name, in some measure with yours while it is in my power, by means of some publication, to do it. the first part of this work, which brought the history to the fall of the western empire, was dedicated to a zealous friend of civil and religious liberty, but in a private station. what he, or any other friend of liberty in europe, could only do by their good wishes, by writing, or by patriot suffering, you, sir, are actually accomplishing, and upon a theatre of great and growing extent. it is the boast of this country to have a constitution the most favourable to political liberty, and private happiness, of any in the world, and all say that it was yourself, more than any other individual, that planned and established it; and to this opinion your conduct in various public offices, and now in the highest, gives the clearest attestation. many have appeared the friends of the rights of man while they were subject to the power of others, and especially when they were sufferers by it; but i do not recollect one besides yourself who retained the same principles, and acted by them, in a station of real power. you, sir, have done more than this; having proposed to relinquish some part of the power which the constitution gave you; and instead of adding to the burden of the people, it has been your endeavour to lighten those burdens tho the necessary consequence must be the diminution of your influence. may this great example, which i doubt not will demonstrate the practicability of truly republican principles, by the actual existence of a form of government calculated to answer all the useful purposes of government (giving equal protection to all, and leaving every man in the possession of every power that he can exercise to his own advantage, without infringing on the equal liberty of others) be followed in other countries, and at length become universal. another reason why i wish to prefix your name to this work, and more appropriate to the subject of it, is that you have ever been a strenuous and uniform advocate of religious no less than civil liberty, both in your own state of virginia, and in the united states in general, seeing in the clearest light the various and great mischiefs that have arisen from any particular form of religion being favoured by the state more than any other; so that the profession or practice of religion is here as free as that of philosophy, or medicine. and now the experience of more than twenty years leaves little room to doubt but that it is a state, of things the most favourable to mutual candour, which is of great importance to domestic peace and good neighbourhood and to the cause of all truth, religious truth least of all excepted. when every question is thus left to free discussion, there cannot be a doubt but that truth will finally prevail, and establish itself by its own evidence; and he must know little of mankind, or of human nature, who can imagine that truth of any kind will be ultimately unfavourable to general happiness. that man must entertain a secret suspicion of his own principles who wishes for any exclusive advantage in his defence or profession of them. having fled from a state of persecution in england, and having been exposed to some degree of danger in the late administration here, i naturally feel the greater satisfaction in the prospect of passing the remainder of an active life (when i naturally wish for repose) under your protection. tho arrived at the usual term of human life it is now only that i can say i see nothing to fear from the hand of power, the government under which i live being for the first time truly favourable to me. and tho it will be evident to all who know me that i have never been swayed by the mean principle of fear, it is certainly a happiness to be out of the possibility of its influence, and to end ones days in peace, enjoying some degree of rest before the state of more perfect rest in the grave, and with the hope of rising to a state of greater activity, security and happiness beyond it. this is all that any man can wish for, or have; and this, sir, under your administration, i enjoy. with the most perfect attachment, and every good wish i subscribe myself not your subject, or humble servant, but your sincere admirer. j. priestley. dear sir, as there are some particulars in a letter i have lately received from mr. stone at paris which i think it will give you pleasure to have, and mr. cooper has been so obliging as to translate them for me, i take the liberty to send them, along with a copy of my _dedication_, with the correction that you suggested, and a note from the latter with which you favoured me concerning what you did with respect to the _constitution_, and which is really more than i had ascribed to you. for almost everything of importance to political liberty in that instrument was, as it appears to me, suggested by you, and as this was unknown to myself, and i believe is so with the world in general, i was unwilling to omit this opportunity of noticing it. i shall be glad if you will be so good as to engage any person sufficiently qualified to draw up such an account of the _constitutional forms_ of this country as my friends say will be agreeable to the emperor, and i will transmit it to mr. stone. not knowing any certain method of sending a letter to france and presuming that you do i take the liberty to inclose my letter to mr. stone. it is, however, so written that no danger can arise to him from it, into whatever hands it may fall. the state of my health, though, i thank god, much improved, will not permit me to avail myself of your kind invitation to pay you a visit. where ever i am, you may depend upon my warmest attachment and best wishes. j. priestley. northumberland oct. , . p.s. i send a copy of the _preface_ as well as of the _dedication_, that you may form some idea of the work you are pleased to patronize. northumberland jan. , . dear sir, as you were pleased to think favourably of my pamphlet entitled _socrates and jesus compared_, i take the liberty to send you a _defence_ of it. my principal object, you will perceive, was to lay hold of the opportunity, given me by mr. b. linn, to excite some attention to doctrines which i consider as of peculiar importance in the christian system, and which i do not find to have been discussed in this country. the church history is, i hope, by this time in the hands of the bookseller at philadelphia, so that you will soon, if my directions have been attended to, receive a copy of the work which i have the honour to dedicate to you. with the greatest respect and attachment, i am dear sir, yours sincerely, j. priestley. dear sir, i take the liberty to send you _a second defence of my pamphlet about socrates_, on the th page of which you will find that i have undertaken the task you were pleased to recommend to me. on giving more attention to it, i found, as the fox did with respect to the lion, that my apprehensions entirely vanished. indeed, i have already accomplished a considerable part of the work, and in about a year from this time i hope to finish the whole, provided my health, which is very precarious, be continued in the state in which it now is. i directed a copy of the _tract on phlogiston_ to be sent to you from philadelphia, and i shall order another, which, together with the inclosed papers, i shall be much obliged to you if you will convey to. mr. livingston. please also to cast an eye over them yourself; and if you can with propriety promote my interest by any representation of yours, i am confident you will do it. when you wrote to me at the commencement of your administration, you said "the only dark speck in our horizon is in louisiana." by your excellent conduct it is now the brightest we have to look to. mr. vaughan having applied to me for a copy of my harmony of the evangelists, which was not to be had in philadelphia, and intimated that it was for you, my son, whose copy is more perfect than mine, begs the honour of your acceptance of it, as a mark of his high esteem, in which he has the hearty concurrence of dear sir, yours sincerely, j. priestley. northumberland dec. , . his european correspondents were informed that he was much engaged with religious matters. while his theological views were not received very graciously yet he found some young men of a serious and inquisitive turn, who read my works, and are confirmed unitarians. in one of his communications to lindsey, written in april , he expresses himself in the following most interesting way relative to his scientific engagements. american men of science will welcome it: this is the message: i send along with this an account of a course of experiments of as much importance as almost any that i have ever made. please to shew it to mr. kirwan, and give it either to mr. nicholson for his journal, or to mr. phillips for his magazine, as you please. i was never more busy or more successful in this way, when i was in england; and i am very thankful to providence for the means and the leisure for these pursuits, which next to theological studies, interest me the most. indeed, there is a natural alliance between them, as there must be between the word and the works of god. he was now at work apparently in his own little laboratory adjacent to his dwelling place. for more than a century this structure has remained practically as it was in the days of priestley. in it he did remarkable things, in his judgment; thus refuting the general idea that after his arrival in america nothing of merit in the scientific direction was accomplished by him. the satisfactory results, mentioned to lindsey, were embodied in a series of "six chemical essays" which eventually found their way into the transactions of the american philosophical society. it is a miscellany of observations. in it are recorded the results found on passing the "vapour of spirit of nitre" over iron turnings, over copper, over perfect charcoal, charcoal of bones, melted lead, tin and bismuth; and there appears a note to the effect that in papin's digester "a solution of caustic alkali, aided by heat, made a _liquor silicum_ with pounded flint glass." there is also given a description of a pyrophorus obtained from iron and sulphur. more interesting, however, was the account of the change of place in different kinds of air, "through several interposing substances," in which priestley recognized distinctly for the first time, the phenomena of gaseous diffusion. there are also references to the absorption of air by water, and of course, as one would expect from the doctor, for it never failed, there is once more emphasized "certain facts pertaining to phlogiston." his friends were quite prepared for such statements. they thought of joseph priestley and involuntarily there arose the idea of phlogiston. the little workshop or laboratory, in northumberland, where these facts were gathered, will soon be removed to the campus of pennsylvania state college. it will be preserved with care and in it, it is hoped, will be gradually assembled everything to be found relating to the noble soul who once disclosed nature's secrets in this simple primitive structure, which american chemists should ever cherish, and hold as a mecca for all who would look back to the beginnings of chemical research in our beloved country. how appropriate it would be could there be deposited in the little laboratory, the apparatus owned and used by priestley, which at present constitutes and for many years past has formed an attractive collection in dickinson college, (pa.) there would be the burning lens, the reflecting telescope, the refracting telescope (probably one of the first achromatic telescopes made), the air-gun, the orrery, and flasks with heavy ground necks, and heavy curved tubes with ground stoppers--all brought (to dickinson) through the instrumentality of thomas cooper, "the greatest man in america in the powers of his mind and acquired information and that without a single exception" according to thomas jefferson. and how the library would add to the glory of the place, but, alas! it has been scattered far and wide, for in , thomas dobson advertised the same for sale in a neatly printed pamphlet of pages. in it were many scarce and valuable books. the appended prices ranged quite widely, reaching in one case the goodly sum of two hundred dollars! and as future chemists visit this unique reminder of dr. priestley it should be remembered that on the piazza of the dwelling house there assembled august , , a group of men who planned then and there for the organization of the present american chemical society. the "essays," previously mentioned, will be found intensely interesting but they are somewhat difficult to read because of their strange nomenclature. here is priestley's account of the method pursued by him to get nitrogen: pure phlogisticated air (nitrogen) may be procured in the easiest and surest manner by the use of iron only--to do this i fill phials with turnings of malleable iron, and having filled them with water, pour it out, to admit the air of the atmosphere, and in six or seven hours it will be diminished ... what remains of the air in the phials will be the purest phlogisticated air (nitrogen). among his contributions to the scientific periodicals of the times there was one relating to the sense of hearing. it is a curious story. one may properly ask whether the singular facts in it were not due to defects in priestley's own organs of hearing. the paper did not arouse comment. it was so out of the ordinary experimental work which he was carrying forward with such genuine pleasure and intense vigour. strong appeals were steadily coming from english friends that he return. while commenting on the pleasure he should have in seeing them he firmly declared that the step would not be wise. in short, despite all arguments he had determined to remain where i am for life. the prejudices against him were abating, although he said that many things are against me; and though they do not _shake_ my faith, they _try_ it. there had gathered a class of fourteen young men about him in the northumberland home. they had adopted his unitarian ideas. to them he lectured regularly on theology and philosophy. those must have been inspiring moments. it was in this wise that the aged philosopher felt he was doing good and was most useful. he said that it was a pretty good class of young men to lecture to. much time was given to his english correspondents. them he advised of the rapid development of the states. he sent to some pictures of the country about him, and with much delight he referred to the fact that jefferson, whom he ardently admired, was now, in the closing weeks of , the president, and his associate--aaron burr, vice-president. he announced to english friends that the late administration, that of john adams, was almost universally reprobated. mr. jefferson, he insisted, "will do nothing rashly," his being president may induce me to visit the federal city, and perhaps his seat in virginia. the seat of government, as may be inferred, had been removed to washington from philadelphia. but to the latter center, which still offered many attractions, priestley journeyed for the third time early in . he was not especially desirous of making this third visit, but as his son and daughter came down a distance of miles on business, he determined to accompany them. true, congress was no longer there, but there were many interesting people about with whom he had great pleasure. with bishop white, who was most orthodox and whom he saw frequently, he enjoyed much "christian and edifying conversation." john andrews was another favorite. he was a violent federalist and informed priestley that the latter had done them (the federalists) more mischief than any other man, yet these two noble spirits lived in amity, and priestley several times announced that dr. andrews was a unitarian, which is not the thought today in regard to the latter. it was an eventful year--this year of . much that was unexpected happened. it brought joy and it brought sorrow. perhaps it would be just as well to note the scientific progress of the doctor during this year, for he gave forth the statement that he had succeeded in producing air by freezing water. this production of air was one of his earlier ideas (p. ), and now he wrote-- the harder the frost was the more air i procured. further, he announced that on heating manganese (dioxide) in inflammable air no water is formed, and what is rather astounding, he was certain that _azote_ consisted of hydrogen and oxygen. to the _medical repository_, which he regarded highly, there was sent a rather thoughtful disquisition on dreams. in it the idea was expressed that dreams have their seat in some region of the brain more deeply seated than that which is occupied by our waking thoughts. a "pile of volta" had been sent out from england. it amused him and he studied it carefully when he was led to remark upon the theory of this curious process as follows: the operation wholly depends on the calcination of the zinc, which suffers a great diminution in weight, while the silver is little affected, and all metals lose their phlogiston in calcination, therefore what remains of the zinc in metallic form in the pile and everything connected with that end of it, is supersaturated with phlogiston. more need not be quoted. it was phlogiston and that only which occasioned the electric current. it may properly be added that in this connection he wrote: it is said the inventor of the galvanic pile discovered the conducting power of charcoal, whereas it was one of my first observations in electricity, made in . some additional attention to air was also given by him, and in so doing he reached the conclusion that the diamond and charcoal of copper are, as nearly as possible, pure phlogiston. one wonders how he could so persuade himself, for these bodies surely possessed weight. why did he not rely more upon his balance? with woodhouse he discussed the product from passing water over heated charcoal. he had been endeavoring to refute certain statements made by cruikshank. there is no question but that he had carbon monoxide in hand, and had it as early as , and that he had obtained it in several different ways. observe this statement: i always found that the first portion of the heavy inflammable air, resulting from the passage of steam over heated charcoal was loaded with fixed air (co_ ), but that in the course of the process this disappeared, the remaining air (co) burning with a lambent flame. scarcely had priestley set foot in philadelphia on his third visitation than the _port folio_, devoted usually to literature and biography, printed the following unkind words: the tricks of dr. priestley to embroil the government, and disturb the religion of his own country, have not the merit of novelty. to which the _aurora_ replied: when porcupine rioted in the filth of a debauched and corrupt faction in this city, no person experienced so much of his obscene and vulgar abuse as dr. priestley. there is not a single fact on record or capable of being shewn, to prove that dr. priestley was guilty of any other crime than being a dissenter from the church of england, and a warm friend of american independence. for this he was abused by porcupine--and denny is only porcupine with a little more tinsel to cover his dirt. it is worthy of remark, that after a whole sheet of promises of "literary lore" and "products of the master of spirits" of the nation--the first and second numbers of the _portable foolery_, are stuffed with extracts from british publications of an ordinary quality. the attack of the port folio was most ungracious. it may have been due to irritation caused by the appearance of a second edition of priestley's "letters to the inhabitants of northumberland." nevertheless the thoughtful and dignified men of the city--men who admired priestley's broad catholic spirit and brave attitude upon all debatable questions, men who appreciated his scientific attainments, invited him to the following subscription dinner, as announced in the _aurora_, march, th: at o'clock in the afternoon about one hundred citizens sat down to an elegant entertainment prepared by mr. francis to celebrate the commencement of the administration of mr. jefferson. the governor honored the company with his presence. several respectable foreigners were invited to partake of the festival.... a variety of patriotic songs were admirably sung; and the following toasts were drank with unanimous applause. . the governor of pennsylvania . dr. priestley: the philosopher and philanthropist.... he was present and enjoyed himself, and sad must it have been to read on march th: some weeks ago, dr. priestley having caught cold by attending a meeting of the philosophical society on a wet evening, was taken ill of a violent inflammatory complaint which rendered his recovery for a long time dubious. we announce with sincere pleasure the returning health of a man, whose life hath hitherto been sedulously and successfully devoted to the interests of mankind. he had, indeed, been very ill. the trouble was pleurisy. dr. rush was his physician. by his order the patient was bled profusely seven times. during this trying and doubtful period there came to him a cheery letter from president jefferson who had only learned of his illness. among other things the president wrote-- yours is one of the few lives precious to mankind, and for the continuance of which every thinking man is solicitous. bigots may be an exception.... but i have got into a long disquisition on politics when i only meant to express my sympathy in the state of your health, and to tender you all the affections of public and private hospitality. i should be very happy to see you here (washington). i leave this about the th to return about the th of april. if you do not leave philadelphia before that, a little excursion hither would help your health. i should be much gratified with the possession of a guest i so much esteem, and should claim a right to lodge you, should you make such an excursion. but priestley journeyed homeward on april th, and en route wrote the following letter, addressed to john vaughan, esq. walnut street, philadelphia, pa.: april , reading, friday evening dear sir, i have the pleasure to inform you, agreeably to your kind request, that we are safely arrived at this place, my daughter better than when we left philadelphia, and as to myself, i feel just as well, and as able to bear any fatigue, as before my late illness. this, however, will always remind me of your friendly attentions, and those of your sister, if a thousand and other circumstances did not do the same, and of them all i hope i shall ever retain a grateful remembrance. along the whole road i am struck with the marks of an astonishing degree of improvement since i came this way four years ago. i do not think that any part of england is better cultivated, and at present the wheat is in a very promising state. i wish we may hear of that of england promising as well. three years of such a scarcity is more than any country could bear, and you will believe me when i say that, if it was in my power, i would guard it not only from famine, but from every other calamity. with my daughter's kindest remembrance, i am, as ever dear sir yours sincerely, j. priestley.[ ] resuming his correspondence with his numerous friends in england, he said: my chief resource is my daily occupation. he also wrote dr. rush his thanks for having advised him to read noah webster's _pestilential disorders_ which follow the appearance of meteors and earthquakes, taking occasion also to excuse his opposition to blood-letting,-- i believe that i owe my life to your judicious direction of it. i shall never forget your so readily forgiving my suspicion, and my requesting the concurrence of dr. wistar after the third bleeding. it was his opinion as well as yours and dr. caldwell's, that my disorder required several more; and the completeness of my cure, and the speediness of my recovery, prove that you were right. in the future i shall never be afraid of the lancet when so judiciously directed. to rush he confided his doubts about his paper on dreams. he cannot account for them, hence he has offered merely an hypothesis, and continues-- i frequently think with much pleasure and regret on the many happy hours i spent in your company, and wish we were not at so great distance. such society would be the value of life to me. but i must acquiesce in what a wise providence has appointed. his friends continued sending him books. and how joyously he received them. at times he would mention special works, as for example,-- please to add gate's answer to wall, and wall's reply; sir john pringle's discourses and life by dr. kippis; chandler's life of king david; colin milne's botanical dictionary, botanic dialogues, and other books of natural history; kirwan's analysis of mineral waters; crosby's history of english baptists. in one of his letters he observed-- a person must be in my situation ... to judge of my feelings when i receive new books. strangely enough a _box_ of books was sent him to carlisle (pa.) and had been there for two years before he learned of it. perhaps a word more may be allowed in regard to the paper on _pestilential disorders_ by noah webster. this was the lexicographer. priestley thought the work curious and important, but the philosophy in it wild and absurd in the extreme. and of rush he asks-- pray is he (webster) a believer in revelation or not? i find several atheists catch at everything favourable to the doctrine of _equivocal generation_; but it must be reprobated by all who are not. chemists will be glad to hear that the annual expense of my laboratory will hardly exceed pounds, and i think i may have done more in proportion to my expenses than any other man. what i have done here, and with little expense, will in time be thought very considerable; but on account of the almost universal reception of the new theory, what i do is not, at present, attended to; but mr. watt and mr. kier, as good chemists as any in europe, approve of my tract on _phlogiston_, and truth will in time prevail over any error. and to another he said, having had great success in my experiments in this country ... i shall never desert philosophy. the following year ( ) had several points of interest in connection with the good doctor; for one, who has followed his career thus far, will wish to call him that. communications from the home country and from france, while not so numerous, were yet full of interesting news. his friend belsham brought out his elements of philosophy of the mind, and although priestley paid it a most gracious tribute he did not hesitate to suggest alterations and additions of various kinds. his dearest friend lindsey fell seriously ill this year. this gave him inexpressible anxiety and grief. as soon as lindsey was, in a measure, restored the fraternal correspondence was resumed. much time was given by the doctor to reading and preparing for the press the volumes of his _church history_ and _notes on the scriptures_. the printing was to be done in northumberland. some doubt was entertained as to whether he would have funds sufficient to pay for the publication, and when the urgent letters from friends tempted him to undertake a european trip he generally replied that he was too far advanced in life, that the general debility produced by pernicious ague rendered him unfit for extended travel, and then he offset the disappointment by saying that the expense of the voyage would more than suffice for the printing of one of his proposed four volumes of the _church history_. this was a most complete, interesting and instructive work. even today one profits by its perusal and an immense fund of worthwhile information and knowledge may be derived from even a cursory study of his _notes on the scriptures_. the monotony of village life was broken by occasional letters from president jefferson. these were most affectionate and also illuminating on national matters. copies of these were sent to english friends with the injunction not to show them or permit them to fall into other hands. dr. thomas cooper was not with priestley in this year ( ), being detained at lancaster where the assembly sat. naturally cooper made himself conspicuous, and priestley prophesied a great future for him, providing that the jealousy entertained for foreigners did not prove too serious an obstacle. priestley took much pleasure at this period in his garden, and wrote, plants, as well as other objects, engage more of my attention than they ever did before.... i wish i knew a little more botany; but old, as i am, i learn something new continually. now and then he mentions a considerable degree of deafness, and sent to philadelphia for a speaking trumpet, but cheerily adds, i am, however, thankful that my eyes do not fail me. here and there occur plaints like these: though my philosophical labours are nearly over, i am glad to hear what is passing in that region in which i once moved, though what i then did seems for the present to be overlooked and forgotten. i am confident, however, as much as i can be of anything, that notwithstanding the almost universal reception of the new theory, which is the cause of it, it is purely chimerical, and cannot keep its ground after a sufficient scrutiny, which may be deferred, but which must take place in time. i am glad to find that mr. cruikshank in england, as well as chemists in france, begin to attend to my objections, though the principal of them have been published many years; but, as you say, many will not read, and therefore they cannot know anything that makes against the opinions they have once adopted. bigotry is not confined to theology. the experimental work for the year was not very great. probably this was the result of his general physical weakness and in part it was due to his preoccupation with literary labours. however, he did write out his results, obtained on heating "finery cinders and charcoal" and thus emphasized the gaseous product of which he observes-- it cannot be denied, however, that this gaseous oxyd of carbon (co) is _inflammable_ ... and is essentially different from all other oxyds, none of which are combustible. along in the month of november he wrote a vigorous protest against cruikshank's explanation of the mode of formation of carbon monoxide. in this polemic he of course threw into prominence his precious phlogiston, the presence of which seemed unnecessary--but this was not so thought by the doctor, who also favored the _medical repository_ with observations on the conversion of iron into steel, in which there is but a single reference to phlogiston, but unfortunately this single reference spoils the general argument and the correct and evident interpretation of the reaction. it reads as follows: iron is convertible into steel by imbibing only _phlogiston_ from the charcoal with which it is cemented. there are abundant correct observations. their interpretation sadly enough is very false, all because of the persistent introduction of phlogiston where it was not essential. priestley advised rush that because of an unhealthy season he had suffered very much from ague, and said,-- tho' i was never robust, i hardly knew what sickness was before my seizure in philadelphia, but the old building has since that had so many shocks, that i am apprehensive it will ere long give way. but i have abundant reason to be satisfied, and shall retire from life _conviva satur_. devotion to work was on the part of priestley, something marvelous. as his son and daughter-in-law were drawn to philadelphia in february, , they carried their father with them. he was rather indisposed to this, yet he disliked remaining alone at home notwithstanding the printing of the church history required considerable personal attention. the marvelous part of it all was that while in philadelphia, on this his fourth and last visit, while he fraternized with congenial souls and even presented himself at various social functions, he yet found leisure to print his little volume entitled "socrates and jesus compared," which gave much pleasure to president jefferson, so much indeed that he hoped priestley would,-- take up the subject on a more extended scale, and show that jesus was truly the most innocent, most benevolent, the most eloquent and sublime character that has ever been exhibited to man. jefferson's genuine approval of his effort was balm to priestley's soul. he, of course, wrote lindsey and belsham about it; yes, copied the letter of jefferson and sent the same to them with the comment,-- he is generally considered as an unbeliever. if so, however, he cannot be far from us, and i hope in the way to be not only _almost_, but _altogether_ what we are. it was february , , that the august members of the american philosophical society resolved: that this society will dine together on saturday next, and that j. b. smith, wistar, williams, hewson & vaughan be a committee to make the necessary arrangements for that purpose and to request dr. priestley's company, informing him that the society are induced to make the request from their high respect for his philosophical labours & discoveries, & to enjoy the more particular pleasure of a social meeting--the dinner to be prepared at the city tavern or farmer's hotel. it was this resolution which caused notices, such as the following to go out to the distinguished membership of the venerable society-- philadelphia, march , sir: you are hereby invited to join the other members of the american philosophical society, in giving a testimony of respect, to their venerable associate dr. joseph priestley, who dines with them on saturday next at francis' hotel--dinner on table at o'clock. c. wistar j. williams j. r. smith t. t. hewson j. vaughan committee an answer will be called for tomorrow morning. dr. rush it was a very dignified and brilliant company. law, medicine, theology, science, commerce represented by very worthy and excellent gentlemen. and, among them sat the modest, unassuming, versatile priestley. that he was happy in his surroundings there is ample reason to believe. he loved to be among men. he, too, was appreciated and eagerly sought because of his winning ways, his tolerance and liberality. he was moderately convivial though he said that one glass of wine at dinner was enough for an old man, but he did not prescribe his own practice as an universal rule. about eight weeks were spent in the city. on return to the dear country home the doctor took up his various duties and burdens, but the infirmities of age were often alluded to by him, and they no doubt delayed all of his work, which was further aggravated by a dangerous fall on his left hip and strain of the muscles of the thigh. he was extremely lame and for some time went about on crutches, which held him out of his laboratory. to him this was very trying. but he persisted. he was truly a splendid example for the younger aspirants for scientific honors. during the year he entered on a controversial article with his old friend erasmus darwin upon the subject of _spontaneous combustion_, and subsequently communicated to the _medical repository_ an account of the conversion of salt into nitre. he had positive knowledge of this fact for quite a little while, and upon the occasion of a visit by dr. wistar, told the latter concerning this with the request that no mention be made of it, evidently that he might have opportunity for additional confirmation. however, very unexpectedly, dr. mitchill published something of a similar character, therefore priestley believing that he ought "to acquaint experimentalists in general with all that i know of the matter," announced that in when experimenting on the formation of air from water, having made use of the same salt, mixed with snow, in every experiment, always evaporating the mixture the salt was recovered dry. i collected the salt when i had done with it, and put it into a glass bottle, with a label expressing what it was, and what use had been made of it. subsequently he treated this salt, after many applications of it, with sulphuric acid, when he remarked-- i was soon surprized to observe that _red vapours_ rose from it. an examination of another portion of the salt showed-- that when it was thrown upon hot coals ... it burned exactly like nitre. so it was a conversion of sodium chloride into sodium nitrate. that this change must have come from the _snow_ with which it had been dissolved, could not be doubted, and he further observed-- now in the upper regions of the atmosphere ... there may be a redundancy of inflammable air ... and a proportion of dephlogisticated air. in that region there are many electrical appearances, as the _aurora borealis_, falling stars &c; in the lower parts of it thunder and lightening, and by these means the two kinds of air may be decomposed, and a highly dephlogisticated nitrous acid, as mine always was, produced. this being formed, will of course, attach itself to any _snow_ or _hail_ that may be forming ... confirming in this unexpected manner, the vulgar opinion of nitre being contained in snow. this seems to be the last communication of this character which came from the doctor's pen. he was in despair relative to the academy which had ever been his hope for the college which in his early years in northumberland he prayed might arise and in which he would be at liberty to particularly impart his unitarian doctrines. an interesting item relative to the academy appeared in the _aurora_ for april st, . it shows that state aid for education was sought in those early days. it is a report, and reads-- a report of the committee to whom was referred the petition of thomas cooper, on behalf of the northumberland academy, praying legislative aid. the report states that thomas cooper appeared before the committee and stated that upward of $ had been expended on the building appropriated to that institution. that the debts due thereon amounted in the whole to near $ . that dr. joseph priestley had the power of disposing of a very valuable library consisting of near volumes of scarce and well chosen books in various branches of literature and science, to any public seminary of learning in the united states, which library, the said dr. priestley was desirous of procuring as a gift to the northumberland academy, provided that institution was likely to receive substantial assistance from the legislature, so as to be enabled to fulfil the purposes of its establishment, that the trustees would have no occasion to ask of the legislature on behalf of that academy, a subscription greater than a few individuals had expended, and were still ready and desirous of contributing thereto; and suggest it to your committee, that if out of the monies due from the county of northumberland to the state a sufficient sum was granted to exonerate the academy from debt, no more would be wanted in the future to effect the purposes of that institution, than a sum equal in amount to the value of the library proposed to be furnished by dr. priestley; such value to be fixed by a person appointed for the purpose by the legislature. the committee was of the opinion that it would be expedient for the legislature to coincide with the suggestion of thomas cooper and so recommended to the legislature. their report was adopted, to . it was strongly advocated by jesse moore, esq., general mitchell and n. ferguson from the city. it was opposed by jacob alter from cumberland, who declared that although there were a great many public schools and colleges and places of that kind scattered over the state, he never knew any good they did, except to breed up a set of idle and odious lawyers to plague the people! at this particular time there still existed confiscated land from the sale of which revenue was derived, and this income it had been agreed upon should be devoted to the erection and support of academies throughout the state. later this scheme was discontinued. but, dr. priestley was not so enthusiastic as formerly. he was occupied with the church history, three volumes of which were in print, and it was expected that the fourth volume would follow shortly thereafter. however, his health was precarious. he could not eat meats, and lived chiefly on broths and soups, saying,-- the defect is in the stomach and liver, and of no common kind. if i hold out till i have finished what i have now on hand, i shall retire from the scene, satisfied and thankful. this was written in august, and the doctor stuck bravely to his literary labors. a few months later he wrote lindsey,-- i really do not expect to survive you. yet, he also entertained the thought that he might,-- assist in the publication of a whole bible, from the several translations of particular books, smoothing and correcting them where i can. january of brought him many interesting, splendid and valuable books from friends in london. he was overjoyed on their arrival. promptly he gave himself to their perusal because his deafness confined him to home and his extreme weakness forbade any excursions. then the winter kept him from his laboratory, and his sole occupation was reading and writing. he entertained a variety of plans, proceeding with some but in the midst of these tasks of love--in the very act of correcting proof, he quietly breathed his last! it was monday, february , , that thomas cooper, the devoted friend of priestley, wrote benjamin rush:-- dear sir: mr. joseph priestley is not at present in spirits to write to his friends, and it falls to my lot therefore to acquaint you that dr. priestley died this morning about o'clock without the slightest degree of apparent pain. he had for some time previous foreseen his dissolution, but he kept up to the last his habitual composure, cheerfulness and kindness. he would have been the th of next month. for about a fortnight there were symptoms of dropsy owing to general debility: about two days before his death, these symptoms disappeared, and a troublesome cough came on perhaps from a translation to the chest. yesterday he had strength enough to look over a revise of the _annotations_ he was publishing on the old and new testament, and this morning he dictated in good language some notices which he wished his son mr. priestley to add to his unpublished works. i am sure you will sincerely regret the decease of a man so highly eminent and useful in the literary and philosophical world, and so much presumably your friend. yes, the valiant old champion of a lost cause was no more. two days before his death "he went to his laboratory"--but, finding his weakness too great, with difficulty returned to his room. loyal to his science to the very end! to american chemists he appeals strongly because of his persistent efforts in research. his coming to this country aroused a real interest in the science which has not waned in the slightest since his demise. when the sad news reached the hall of the american philosophical society, dr. benjamin smith barton was chosen to eulogize priestley. this notable event took place on january rd, . the _aurora_ reported: dr. benjamin smith barton, one of the vice-presidents of the american philosophical society, having been previously appointed by the society to deliver an eulogium to the memory of their late associate, dr. joseph priestley, the same was accordingly delivered in the first presbyterian church in this city, on thursday the rd inst. before the society, who went in a body from their hall to the church, preceded by their patron, the governor of the state. invitations were given on this occasion to the revd. clergy of the city; the college of physicians; the medical society; the gentlemen of the bar, with the students at law; the trustees and faculty of the university of pennsylvania, with their students in the arts and in medicine; the judges and officers of the federal and state courts; the foreign ministers and other public characters then in the city; the mayor; aldermen and city councils: the trustees and session of the first presbyterian church; the directors of the city library; the directors and physicians of the pennsylvania hospital, of the alms house, and of the dispensary; the proprietor and director of the philadelphia museum; and the contributors towards the cabinet and library of the society. after the conclusion of a very interesting eulogium, the society returned their thanks to the orator, and requested a copy for the purpose of publication. one's curiosity is quickened on thinking what barton said in his address. search in many directions failed to bring forth the eulogium. it had been ordered to be printed in the transactions of the society. this was never done. but there was a minute (seven years later) in the meeting of the society (nov. , ) to the effect that dr. barton's request for permission to withdraw it (eulogium) to be enlarged and published separately was referred for consideration to the next meeting. the request was granted at the next meeting, but nowhere among barton's literary remains was the precious document to be found. lost very probably--when it might have revealed so much. priestley's death was deeply mourned throughout the land. the public prints brought full and elaborate accounts of his life, and touching allusions to the fullness of his brilliant career. such expressions as these were heard,-- as a metaphysician he stands foremost among those who have attempted the investigation of its abstruse controversies. as a politician he assiduously and successfully laboured to extend and illustrate those general principles of civil liberty which are happily the foundation of the constitution of his adopted country,-- his profound attention to the belles-lettres, and to the other departments of general literature, has been successfully exemplified among his other writings, by his lectures on oratory and criticism, and on general history and policy,-- of the most important and fashionable study of _pneumatic chemistry_ he may fairly be said to be the father. he was a man of restless activity, but he uniformly directed that activity to what seemed to him the public good, seeking neither emolument nor honour from men. dr. priestley was possessed of great ardour and vivacity of intellect.... his integrity was unimpeachable; and even malice itself could not fix a stain on his private character. and what a splendid tribute is contained in the following passages from cuvier: priestley, loaded with glory, was modest enough to be astonished at his good fortune, and at the multitude of beautiful facts, which nature seemed to have revealed to him alone. he forgot that her favours were not gratuitous, and if she had so well explained herself, it was because he had known how to oblige her to do so by his indefatigable perseverance in questioning her, and by the thousand ingenious means he had taken to snatch her answers from her. others carefully hide that which they owe to chance; priestley seemed to wish to ascribe all his merit to fortuitous circumstances, remarking, with unexampled candour, how many times he had profited by them, without knowing it, how many times he was in possession of new substances without having perceived them; and he never dissimulated the erroneous views which sometimes directed his efforts, and from which he was only undeceived by experience. these confessions did honour to his modesty, without disarming jealousy. those to whom their own ways and methods had never discovered anything called him a simple worker of experiments, without method and without an object "it is not astonishing," they added, "that among so many trials and combinations, he should find some that were fortunate." but real natural philosophers were not duped by these selfish criticisms. many encomiums like the preceding--yes, a thousandfold--could easily be gathered if necessary to show the regard and confidence held for this remarkable man to whom america is truly very deeply indebted. some years ago the writer paid a visit to the god's acre of northumberland. he arrived after dark and was conveyed to the sacred place in an automobile. soon the car stopped. its headlights illuminated the upright flat stone which marked the last resting place of the great chemist, and in that light not only was the name of the sleeper clearly read but the less distinct but legible epitaph: return unto thy rest, o my soul, for the lord hath dealt bountifully with thee. i will lay me down in peace and sleep till i wake in the morning of the resurrection. pondering on these lines there slowly returned to mind the words of franklin's epitaph,--franklin, who, years before, had encouraged and aided the noble exile, who was ever mindful of the former's goodness to him: the body of benjamin franklin printer (like the cover of an old book its contents torn out and stript of its lettering and gilding) lies here food for worms but the work shall not be lost for it will (as he believed) appear once more in a new and more elegant edition revised and corrected by the author and then, by some strange mental reaction, there floated before the writer the paragraph uttered by professor huxley, when in a statue to priestley was unveiled in the city of birmingham: our purpose is to do honour ... to priestley the peerless defender of national freedom in thought and in action; to priestley the philosophical thinker; to that priestley who held a foremost place among the 'swift runners who hand over the lamp of life,' and transmit from one generation to another the fire kindled, in the childhood of the world, at the promethean altar of science. footnotes: [footnote : chemistry in old philadelphia, j. b. lippincott co., phila., pa.] [footnote : correspondence of priestley by h. c. bolton, new york, .] [footnote : mr. berthollet discovered that oxygenated muriatic gas, received in a ley of caustic potash, forms a chrystallizable neutral salt, which detonates more strongly than nitre.] [footnote : nine famous birmingham men--cornish brothers, publishers, .] [footnote : james woodhouse--a pioneer in chemistry--j. c. winston co., phila.-- .] [footnote : james woodhouse--a pioneer in chemistry--j. c. winston co., phila.-- .] [footnote : see _chemistry in america_, appleton & co. and _chemistry in old philadelphia_, the j. b. lippincott co., philadelphia, pa.] [footnote : the original of this letter is now the property of dr. c. a. browne, new york. he graciously permitted it to be inserted here.] transcriber's notes: ==================== formatting, fixed in text: ========== a few inconsistencies in the layout and formatting of the book have been corrected (an extra blank line in a quoted paragraph, for example). most notably, the "hints concerning public education" is an essay by priestley quoted verbatim in the text. the original layout did not make a clear distinction between smith's text and this quoted essay; i have remedied this with an indent for that section. typos, fixed in text: ===== it was an interesting fact (text reads inter-resting, broken across a line) that germ which might once have been supposed (text reads beeen) september , (text reads september, ) the doctor remained quietly at home (text reads quitely) on behalf of the northumberland academy, praying legislative aid (text reads lesiglative) science which has not waned in the slightest (text reads slighest) he uniformly directed that activity (text reads uniformily) from the rod of lawless power (text reads of of) almost all the fresh meat they have (text reads flesh meat) diversions, beginning with the publication (text reads begining) rather thoughtful disquisition on dreams (text reads disquisiton) footnote : j. c. winston co. (text reads wintson) apparent errata, but could be as appearing in the original letters: =============== (left as-is in text). conduct will evince that i have been to that of great {great} britain. contributes so much as ours do to the cummunication {communication} of useful knowledge sense of security which scientificial {scientific?} pursuits require the same that has been called _philogiston_ {phlogiston} he would never enter the puplit {pulpit} again. until it became necesary {necessary} to separate. we all rejoiced at the aggreeable {agreeable} information by civil fueds {feuds} exiled my native home unless you were possessed of _aladin's {aladdin's} lamp_ transcriber's note: no evidence was found to indicate the copyright on this book was renewed. the girl in the golden atom by ray cummings to my friend and mentor robert h. davis with grateful acknowledgment of his encouragement and practical assistance to which i owe my initial success contents i. a universe in an atom ii. into the ring iii. after forty-eight hours iv. lylda v. the world in the ring vi. strategy and kisses vii. a modern gulliver viii. "i must go back" ix. after five years x. testing the drugs xi. the escape of the drug xii. the start xiii. perilous ways xiv. strange experiences xv. the valley of the scratch xvi. the pit of darkness xvii. the welcome of the master xviii. the chemist and his son xix. the city of arite xx. the world of the ring xxi. a life worth living xxii. the trial xxiii. lylda's plan xxiv. lylda acts xxv. the escape of targo xxvi. the abduction xxvii. aura xxviii. the attack on the palace xxix. on the lake xxx. word music xxxi. the palace of orlog xxxii. an ant-hill outraged xxxiii. the rescue of loto xxxiv. the decision xxxv. good-bye to arite xxxvi. the fight in the tunnels xxxvii. a combat of titans xxxviii. lost in size xxxix. a modern dinosaur xl. the adventurers' return xli. the first christmas the girl in the golden atom chapter i a universe in an atom "then you mean to say there is no such thing as the _smallest_ particle of matter?" asked the doctor. "you can put it that way if you like," the chemist replied. "in other words, what i believe is that things can be infinitely small just as well as they can be infinitely large. astronomers tell us of the immensity of space. i have tried to imagine space as finite. it is impossible. how can you conceive the edge of space? something must be beyond--something or nothing, and even that would be more space, wouldn't it?" "gosh," said the very young man, and lighted another cigarette. the chemist resumed, smiling a little. "now, if it seems probable that there is no limit to the immensity of space, why should we make its smallness finite? how can you say that the atom cannot be divided? as a matter of fact, it already has been. the most powerful microscope will show you realms of smallness to which you can penetrate no other way. multiply that power a thousand times, or ten thousand times, and who shall say what you will see?" the chemist paused, and looked at the intent little group around him. he was a youngish man, with large features and horn-rimmed glasses, his rough english-cut clothes hanging loosely over his broad, spare frame. the banker drained his glass and rang for the waiter. "very interesting," he remarked. "don't be an ass, george," said the big business man. "just because you don't understand, doesn't mean there is no sense to it." "what i don't get clearly"--began the doctor. "none of it's clear to me," said the very young man. the doctor crossed under the light and took an easier chair. "you intimated you had discovered something unusual in these realms of the infinitely small," he suggested, sinking back luxuriously. "will you tell us about it?" "yes, if you like," said the chemist, turning from one to the other. a nod of assent followed his glance, as each settled himself more comfortably. "well, gentlemen, when you say i have discovered something unusual in another world--in the world of the infinitely small--you are right in a way. i have seen something and lost it. you won't believe me probably," he glanced at the banker an instant, "but that is not important. i am going to tell you the facts, just as they happened." the big business man filled up the glasses all around, and the chemist resumed: "it was in , this problem first came to interest me. i had never gone in for microscopic work very much, but now i let it absorb all my attention. i secured larger, more powerful instruments--i spent most of my money," he smiled ruefully, "but never could i come to the end of the space into which i was looking. something was always hidden beyond--something i could almost, but not quite, distinguish. "then i realized that i was on the wrong track. my instrument was not merely of insufficient power, it was not one-thousandth the power i needed. "so i began to study the laws of optics and lenses. in i went abroad, and with one of the most famous lens-makers of europe i produced a lens of an entirely different quality, a lens that i hoped would give me what i wanted. so i returned here and fitted up my microscope that i knew would prove vastly more powerful than any yet constructed. "it was finally completed and set up in my laboratory, and one night i went in alone to look through it for the first time. it was in the fall of , i remember, just after the first declaration of war. "i can recall now my feelings at that moment. i was about to see into another world, to behold what no man had ever looked on before. what would i see? what new realms was i, first of all our human race, to enter? with furiously beating heart, i sat down before the huge instrument and adjusted the eyepiece. "then i glanced around for some object to examine. on my finger i had a ring, my mother's wedding-ring, and i decided to use that. i have it here." he took a plain gold band from his little finger and laid it on the table. "you will see a slight mark on the outside. that is the place into which i looked." his friends crowded around the table and examined a scratch on one side of the band. "what did you see?" asked the very young man eagerly. "gentlemen," resumed the chemist, "what i saw staggered even my own imagination. with trembling hands i put the ring in place, looking directly down into that scratch. for a moment i saw nothing. i was like a person coming suddenly out of the sunlight into a darkened room. i knew there was something visible in my view, but my eyes did not seem able to receive the impressions. i realize now they were not yet adjusted to the new form of light. gradually, as i looked, objects of definite shape began to emerge from the blackness. "gentlemen, i want to make clear to you now--as clear as i can--the peculiar aspect of everything that i saw under this microscope. i seemed to be inside an immense cave. one side, near at hand, i could now make out quite clearly. the walls were extraordinarily rough and indented, with a peculiar phosphorescent light on the projections and blackness in the hollows. i say phosphorescent light, for that is the nearest word i can find to describe it--a curious radiation, quite different from the reflected light to which we are accustomed. "i said that the hollows inside of the cave were blackness. but not blackness--the absence of light--as we know it. it was a blackness that seemed also to radiate light, if you can imagine such a condition; a blackness that seemed not empty, but merely withholding its contents just beyond my vision. "except for a dim suggestion of roof over the cave, and its floor, i could distinguish nothing. after a moment this floor became clearer. it seemed to be--well, perhaps i might call it black marble--smooth, glossy, yet somewhat translucent. in the foreground the floor was apparently liquid. in no way did it differ in appearance from the solid part, except that its surface seemed to be in motion. "another curious thing was the outlines of all the shapes in view. i noticed that no outline held steady when i looked at it directly; it seemed to quiver. you see something like it when looking at an object through water--only, of course, there was no distortion. it was also like looking at something with the radiation of heat between. "of the back and other side of the cave, i could see nothing, except in one place, where a narrow effulgence of light drifted out into the immensity of the distance behind. "i do not know how long i sat looking at this scene; it may have been several hours. although i was obviously in a cave, i never felt shut in--never got the impression of being in a narrow, confined space. "on the contrary, after a time i seemed to feel the vast immensity of the blackness before me. i think perhaps it may have been that path of light stretching out into the distance. as i looked it seemed like the reversed tail of a comet, or the dim glow of the milky way, and penetrating to equally remote realms of space. "perhaps i fell asleep, or at least there was an interval of time during which i was so absorbed in my own thoughts i was hardly conscious of the scene before me. "then i became aware of a dim shape in the foreground--a shape merged with the outlines surrounding it. and as i looked, it gradually assumed form, and i saw it was the figure of a young girl, sitting beside the liquid pool. except for the same waviness of outline and phosphorescent glow, she had quite the normal aspect of a human being of our own world. she was beautiful, according to our own standards of beauty; her long braided hair a glowing black, her face, delicate of feature and winsome in expression. her lips were a deep red, although i felt rather than saw the colour. "she was dressed only in a short tunic of a substance i might describe as gray opaque glass, and the pearly whiteness of her skin gleamed with iridescence. "she seemed to be singing, although i heard no sound. once she bent over the pool and plunged her hand into it, laughing gaily. "gentlemen, i cannot make you appreciate my emotions, when all at once i remembered i was looking through a microscope. i had forgotten entirely my situation, absorbed in the scene before me. and then, abruptly, a great realization came upon me--the realization that everything i saw was inside that ring. i was unnerved for the moment at the importance of my discovery. "when i looked again, after the few moments my eye took to become accustomed to the new form of light, the scene showed itself as before, except that the girl had gone. "for over a week, each night at the same time i watched that cave. the girl came always, and sat by the pool as i had first seen her. once she danced with the wild grace of a wood nymph, whirling in and out the shadows, and falling at last in a little heap beside the pool. "it was on the tenth night after i had first seen her that the accident happened. i had been watching, i remember, an unusually long time before she appeared, gliding out of the shadows. she seemed in a different mood, pensive and sad, as she bent down over the pool, staring into it intently. suddenly there was a tremendous cracking sound, sharp as an explosion, and i was thrown backward upon the floor. "when i recovered consciousness--i must have struck my head on something--i found the microscope in ruins. upon examination i saw that its larger lens had exploded--flown into fragments scattered around the room. why i was not killed i do not understand. the ring i picked up from the floor; it was unharmed and unchanged. "can i make you understand how i felt at this loss? because of the war in europe i knew i could never replace my lens--for many years, at any rate. and then, gentlemen, came the most terrible feeling of all; i knew at last that the scientific achievement i had made and lost counted for little with me. it was the girl. i realized then that the only being i ever could care for was living out her life with her world, and, indeed, her whole universe, in an atom of that ring." the chemist stopped talking and looked from one to the other of the tense faces of his companions. "it's almost too big an idea to grasp," murmured the doctor. "what caused the explosion?" asked the very young man. "i do not know." the chemist addressed his reply to the doctor, as the most understanding of the group. "i can appreciate, though, that through that lens i was magnifying tremendously those peculiar light-radiations that i have described. i believe the molecules of the lens were shattered by them--i had exposed it longer to them that evening than any of the others." the doctor nodded his comprehension of this theory. impressed in spite of himself, the banker took another drink and leaned forward in his chair. "then you really think that there is a girl now inside the gold of that ring?" he asked. "he didn't say that necessarily," interrupted the big business man. "yes, he did." "as a matter of fact, i do believe that to be the case," said the chemist earnestly. "i believe that every particle of matter in our universe contains within it an equally complex and complete a universe, which to its inhabitants seems as large as ours. i think, also that the whole realm of our interplanetary space, our solar system and all the remote stars of the heavens are contained within the atom of some other universe as gigantic to us as we are to the universe in that ring." "gosh!" said the very young man. "it doesn't make one feel very important in the scheme of things, does it?" remarked the big business man dryly. the chemist smiled. "the existence of no individual, no nation, no world, nor any one universe is of the least importance." "then it would be possible," said the doctor, "for this gigantic universe that contains us in one of its atoms, to be itself contained within the atom of another universe, still more gigantic, and so on." "that is my theory," said the chemist. "and in each of the atoms of the rocks of that cave there may be other worlds proportionately minute?" "i can see no reason to doubt it." "well, there is no proof, anyway," said the banker. "we might as well believe it." "i intend to get proof," said the chemist. "do you believe all these innumerable universes, both larger and smaller than ours, are inhabited?" asked the doctor. "i should think probably most of them are. the existence of life, i believe, is as fundamental as the existence of matter without life." "how do you suppose that girl got in there?" asked the very young man, coming out of a brown study. "what puzzled me," resumed the chemist, ignoring the question, "is why the girl should so resemble our own race. i have thought about it a good deal, and i have reached the conclusion that the inhabitants of any universe in the next smaller or larger plane to ours probably resemble us fairly closely. that ring, you see, is in the same--shall we say--environment as ourselves. the same forces control it that control us. now, if the ring had been created on mars, for instance, i believe that the universes within its atoms would be inhabited by beings like the martians--if mars has any inhabitants. of course, in planes beyond those next to ours, either smaller or larger, changes would probably occur, becoming greater as you go in or out from our own universe." "good lord! it makes one dizzy to think of it," said the big business man. "i wish i knew how that girl got in there," sighed the very young man, looking at the ring. "she probably didn't," retorted the doctor. "very likely she was created there, the same as you were here." "i think that is probably so," said the chemist. "and yet, sometimes i am not at all sure. she was very human." the very young man looked at him sympathetically. "how are you going to prove your theories?" asked the banker, in his most irritatingly practical way. the chemist picked up the ring and put it on his finger. "gentlemen," he said. "i have tried to tell you facts, not theories. what i saw through that ultramicroscope was not an unproven theory, but a fact. my theories you have brought out by your questions." "you are quite right," said the doctor; "but you did mention yourself that you hoped to provide proof." the chemist hesitated a moment, then made his decision. "i will tell you the rest," he said. "after the destruction of the microscope, i was quite at a loss how to proceed. i thought about the problem for many weeks. finally i decided to work along another altogether different line--a theory about which i am surprised you have not already questioned me." he paused, but no one spoke. "i am hardly ready with proof to-night," he resumed after a moment. "will you all take dinner with me here at the club one week from to-night?" he read affirmation in the glance of each. "good. that's settled," he said, rising. "at seven, then." "but what was the theory you expected us to question you about?" asked the very young man. the chemist leaned on the back of his chair. "the only solution i could see to the problem," he said slowly, "was to find some way of making myself sufficiently small to be able to enter that other universe. i have found such a way and one week from to-night, gentlemen, with your assistance, i am going to enter the surface of that ring at the point where it is scratched!" chapter ii into the ring the cigars were lighted and dinner over before the doctor broached the subject uppermost in the minds of every member of the party. "a toast, gentlemen," he said, raising his glass. "to the greatest research chemist in the world. may he be successful in his adventure to-night." the chemist bowed his acknowledgment. "you have not heard me yet," he said smiling. "but we want to," said the very young man impulsively. "and you shall." he settled himself more comfortably in his chair. "gentlemen, i am going to tell you, first, as simply as possible, just what i have done in the past two years. you must draw your own conclusions from the evidence i give you. "you will remember that i told you last week of my dilemma after the destruction of the microscope. its loss and the impossibility of replacing it, led me into still bolder plans than merely the visual examination of this minute world. i reasoned, as i have told you, that because of its physical proximity, its similar environment, so to speak, this outer world should be capable of supporting life identical with our own. "by no process of reasoning can i find adequate refutation of this theory. then, again, i had the evidence of my own eyes to prove that a being i could not tell from one of my own kind was living there. that this girl, other than in size, differs radically from those of our race, i cannot believe. "i saw then but one obstacle standing between me and this other world--the discrepancy of size. the distance separating our world from this other is infinitely great or infinitely small, according to the viewpoint. in my present size it is only a few feet from here to the ring on that plate. but to an inhabitant of that other world, we are as remote as the faintest stars of the heavens, diminished a thousand times." he paused a moment, signing the waiter to leave the room. "this reduction of bodily size, great as it is, involves no deeper principle than does a light contraction of tissue, except that it must be carried further. the problem, then, was to find a chemical, sufficiently unharmful to life, that would so act upon the body cells as to cause a reduction in bulk, without changing their shape. i had to secure a uniform and also a proportionate rate of contraction of each cell, in order not to have the body shape altered. "after a comparatively small amount of research work, i encountered an apparently insurmountable obstacle. as you know, gentlemen, our living human bodies are held together by the power of the central intelligence we call the mind. every instant during your lifetime your subconscious mind is commanding and directing the individual life of each cell that makes up your body. at death this power is withdrawn; each cell is thrown under its own individual command, and dissolution of the body takes place. "i found, therefore, that i could not act upon the cells separately, so long as they were under control of the mind. on the other hand, i could not withdraw this power of the subconscious mind without causing death. "i progressed no further than this for several months. then came the solution. i reasoned that after death the body does not immediately disintegrate; far more time elapses than i expected to need for the cell-contraction. i devoted my time, then to finding a chemical that would temporarily withhold, during the period of cell-contraction, the power of the subconscious mind, just as the power of the conscious mind is withheld by hypnotism. "i am not going to weary you by trying to lead you through the maze of chemical experiments into which i plunged. only one of you," he indicated the doctor, "has the technical basis of knowledge to follow me. no one had been before me along the path i traversed. i pursued the method of pure theoretical deduction, drawing my conclusions from the practical results obtained. "i worked on rabbits almost exclusively. after a few weeks i succeeded in completely suspending animation in one of them for several hours. there was no life apparently existing during that period. it was not a trance or coma, but the complete simulation of death. no harmful results followed the revivifying of the animal. the contraction of the cells was far more difficult to accomplish; i finished my last experiment less than six months ago." "then you really have been able to make an animal infinitely small?" asked the big business man. the chemist smiled. "i sent four rabbits into the unknown last week," he said. "what did they look like going?" asked the very young man. the chemist signed him to be patient. "the quantity of diminution to be obtained bothered me considerably. exactly how small that other universe is, i had no means of knowing, except by the computations i made of the magnifying power of my lens. these figures, i know, must necessarily be very inaccurate. then, again, i have no means of judging by the visual rate of diminution of these rabbits, whether this contraction is at a uniform rate or accelerated. nor can i tell how long it is prolonged, for the quantity of drug administered, as only a fraction of the diminution has taken place when the animal passes beyond the range of any microscope i now possess. "these questions were overshadowed, however, by a far more serious problem that encompassed them all. "as i was planning to project myself into this unknown universe and to reach the exact size proportionate to it, i soon realized such a result could not be obtained were i in an unconscious state. only by successive doses of the drug, or its retardent about which i will tell you later, could i hope to reach the proper size. another necessity is that i place myself on the exact spot on that ring where i wish to enter and to climb down among its atoms when i have become sufficiently small to do so. obviously, this would be impossible to one not possessing all his faculties and physical strength." "and did you solve that problem, too?" asked the banker. "i'd like to see it done," he added, reading his answer in the other's confident smile. the chemist produced two small paper packages from his wallet. "these drugs are the result of my research," he said. "one of them causes contraction, and the other expansion, by an exact reversal of the process. taken together, they produce no effect, and a lesser amount of one retards the action of the other." he opened the papers, showing two small vials. "i have made them as you see, in the form of tiny pills, each containing a minute quantity of the drug. it is by taking them successively in unequal amounts that i expect to reach the desired size." "there's one point that you do not mention," said the doctor. "those vials and their contents will have to change size as you do. how are you going to manage that?" "by experimentation i have found," answered the chemist, "that any object held in close physical contact with the living body being contracted is contracted itself at an equal rate. i believe that my clothes will be affected also. these vials i will carry strapped under my armpits." "suppose you should die, or be killed, would the contraction cease?" asked the doctor. "yes, almost immediately," replied the chemist. "apparently, though i am acting through the subconscious mind while its power is held in abeyance, when this power is permanently withdrawn by death, the drug no longer affects the individual cells. the contraction or expansion ceases almost at once." the chemist cleared a space before him on the table. "in a well-managed club like this," he said, "there should be no flies, but i see several around. do you suppose we can catch one of them?" "i can," said the very young man, and forthwith he did. the chemist moistened a lump of sugar and laid it on the table before him. then, selecting one of the smallest of the pills, he ground it to powder with the back of a spoon and sprinkled this powder on the sugar. "will you give me the fly, please?" the very young man gingerly did so. the chemist held the insect by its wings over the sugar. "will someone lend me one of his shoes?" the very young man hastily slipped off a dancing pump. "thank you," said the chemist, placing it on the table with a quizzical smile. the rest of the company rose from their chairs and gathered around, watching with interested faces what was about to happen. "i hope he is hungry," remarked the chemist, and placed the fly gently down on the sugar, still holding it by the wings. the insect, after a moment, ate a little. silence fell upon the group as each watched intently. for a few moments nothing happened. then, almost imperceptibly at first, the fly became larger. in another minute it was the size of a large horse-fly, struggling to release its wings from the chemist's grasp. a minute more and it was the size of a beetle. no one spoke. the banker moistened his lips, drained his glass hurriedly and moved slightly farther away. still the insect grew; now it was the size of a small chicken, the multiple lens of its eyes presenting a most terrifying aspect, while its ferocious droning reverberated through the room. then suddenly the chemist threw it upon the table, covered it with a napkin, and beat it violently with the slipper. when all movement had ceased he tossed its quivering body into a corner of the room. "good god!" ejaculated the banker, as the white-faced men stared at each other. the quiet voice of the chemist brought them back to themselves. "that, gentlemen, you must understand, was only a fraction of the very first stage of growth. as you may have noticed, it was constantly accelerated. this acceleration attains a speed of possibly fifty thousand times that you observed. beyond that, it is my theory, the change is at a uniform rate." he looked at the body of the fly, lying inert on the floor. "you can appreciate now, gentlemen, the importance of having this growth cease after death." "good lord, i should say so!" murmured the big business man, mopping his forehead. the chemist took the lump of sugar and threw it into the open fire. "gosh!" said the very young man, "suppose when we were not looking, another fly had----" "shut up!" growled the banker. "not so skeptical now, eh, george?" said the big business man. "can you catch me another fly?" asked the chemist. the very young man hastened to do so. "the second demonstration, gentlemen," said the chemist, "is less spectacular, but far more pertinent than the one you have just witnessed." he took the fly by the wings, and prepared another lump of sugar, sprinkling a crushed pill from the other vial upon it. "when he is small enough i am going to try to put him on the ring, if he will stay still," said the chemist. the doctor pulled the plate containing the ring forward until it was directly under the light, and every one crowded closer to watch; already the fly was almost too small to be held. the chemist tried to set it on the ring, but could not; so with his other hand he brushed it lightly into the plate, where it lay, a tiny black speck against the gleaming whiteness of the china. "watch it carefully, gentlemen," he said, as they bent closer. "it's gone," said the big business man. "no, i can still see it," said the doctor. then he raised the plate closer to his face. "now it's gone," he said. the chemist sat down in his chair. "it's probably still there, only too small for you to see. in a few minutes, if it took a sufficient amount of the drug, it will be small enough to fall between the molecules of the plate." "do you suppose it will find another inhabited universe down there?" asked the very young man. "who knows," smiled the chemist. "very possibly it will. but the one we are interested in is here," he added, touching the ring. "is it your intention to take this stuff yourself to-night?" asked the big business man. "if you will give me your help, i think so, yes. i have made all arrangements. the club has given us this room in absolute privacy for forty-eight hours. your meals will be served here when you want them, and i am going to ask you, gentlemen, to take turns watching and guarding the ring during that time. will you do it?" "i should say we would," cried the doctor, and the others nodded assent. "it is because i wanted you to be convinced of my entire sincerity that i have taken you so thoroughly into my confidence. are those doors locked?" the very young man locked them. "thank you," said the chemist, starting to disrobe. in a moment he stood before them attired in a woolen bathing-suit of pure white. over his shoulders was strapped tightly a narrow leather harness, supporting two silken pockets, one under each armpit. into each of these he placed one of the vials, first laying four pills from one of them upon the table. at this point the banker rose from his chair and selected another in the further corner of the room. he sank into it a crumpled heap and wiped the beads of perspiration from his face with a shaking hand. "i have every expectation," said the chemist, "that this suit and harness will contract in size uniformly with me. if the harness should not, then i shall have to hold the vials in my hand." on the table, directly under the light, he spread a large silk handkerchief, upon which he placed the ring. he then produced a teaspoon, which he handed to the doctor. "please listen carefully," he said, "for perhaps the whole success of my adventure, and my life itself, may depend upon your actions during the next few minutes. you will realize, of course, that when i am still large enough to be visible to you i shall be so small that my voice may be inaudible. therefore, i want you to know, now, just what to expect. "when i am something under a foot high, i shall step upon that handkerchief, where you will see my white suit plainly against its black surface. when i become less than an inch high, i shall run over to the ring and stand beside it. when i have diminished to about a quarter of an inch, i shall climb upon it, and, as i get smaller, will follow its surface until i come to the scratch. "i want you to watch me very closely. i may miscalculate the time and wait until i am too small to climb upon the ring. or i may fall off. in either case, you will place that spoon beside me and i will climb into it. you will then do your best to help me get on the ring. is all this quite clear?" the doctor nodded assent. "very well, watch me as long as i remain visible. if i have an accident, i shall take the other drug and endeavor to return to you at once. this you must expect at any moment during the next forty-eight hours. under all circumstances, if i am alive, i shall return at the expiration of that time. "and, gentlemen, let me caution you most solemnly, do not allow that ring to be touched until that length of time has expired. can i depend on you?" "yes," they answered breathlessly. "after i have taken the pills," the chemist continued, "i shall not speak unless it is absolutely necessary. i do not know what my sensations will be, and i want to follow them as closely as possible." he then turned out all the lights in the room with the exception of the center electrolier, that shone down directly on the handkerchief and ring. the chemist looked about him. "good-by, gentlemen," he said, shaking hands all round. "wish me luck," and without hesitation he placed the four pills in his mouth and washed them down with a swallow of water. silence fell on the group as the chemist seated himself and covered his face with his hands. for perhaps two minutes the tenseness of the silence was unbroken, save by the heavy breathing of the banker as he lay huddled in his chair. "oh, my god! he _is_ growing smaller!" whispered the big business man in a horrified tone to the doctor. the chemist raised his head and smiled at them. then he stood up, steadying himself against a chair. he was less than four feet high. steadily he grew smaller before their horrified eyes. once he made, as if to speak, and the doctor knelt down beside him. "it's all right, good-by," he said in a tiny voice. then he stepped upon the handkerchief. the doctor knelt on the floor beside it, the wooden spoon ready in his hand, while the others, except the banker, stood behind him. the figure of the chemist, standing motionless near the edge of the handkerchief, seemed now like a little white wooden toy, hardly more than an inch in height. waving his hand and smiling, he suddenly started to walk and then ran swiftly over to the ring. by the time he reached it, somewhat out of breath, he was little more than twice as high as the width of its band. without pausing, he leaped up, and sat astraddle, leaning over and holding to it tightly with his hands. in another moment he was on his feet, on the upper edge of the ring, walking carefully along its circumference towards the scratch. the big business man touched the doctor on the shoulder and tried to smile. "he's making it," he whispered. as if in answer the little figure turned and waved its arms. they could just distinguish its white outline against the gold surface underneath. "i don't see him," said the very young man in a scared voice. "he's right near the scratch," answered the doctor, bending closer. then, after a moment, "he's gone." he rose to his feet. "good lord! why haven't we a microscope!" "i never thought of that," said the big business man, "we could have watched him for a long time yet." "well, he's gone now," returned the doctor, "and there is nothing for us to do but wait." "i hope he finds that girl," sighed the very young man, as he sat chin in hand beside the handkerchief. chapter iii after forty-eight hours the banker snored stertorously from his mattress in a corner of the room. in an easy-chair near by, with his feet on the table, lay the very young man, sleeping also. the doctor and the big business man sat by the handkerchief conversing in low tones. "how long has it been now?" asked the latter. "just forty hours," answered the doctor; "and he said that forty-eight hours was the limit. he should come back at about ten to-night." "i wonder if he _will_ come back," questioned the big business man nervously. "lord, i wish _he_ wouldn't snore so loud," he added irritably, nodding in the direction of the banker. they were silent for a moment, and then he went on: "you'd better try to sleep a little while, frank. you're worn out. i'll watch here." "i suppose i should," answered the doctor wearily. "wake up that kid, he's sleeping most of the time." "no, i'll watch," repeated the big business man. "you lie down over there." the doctor did so while the other settled himself more comfortably on a cushion beside the handkerchief, and prepared for his lonely watching. the doctor apparently dropped off to sleep at once, for he did not speak again. the big business man sat staring steadily at the ring, bending nearer to it occasionally. every ten or fifteen minutes he looked at his watch. perhaps an hour passed in this way, when the very young man suddenly sat up and yawned. "haven't they come back yet?" he asked in a sleepy voice. the big business man answered in a much lower tone. "what do you mean--they?" "i dreamed that he brought the girl back with him," said the very young man. "well, if he did, they have not arrived. you'd better go back to sleep. we've got six or seven hours yet--maybe more." the very young man rose and crossed the room. "no, i'll watch a while," he said, seating himself on the floor. "what time is it?" "quarter to three." "he said he'd be back by ten to-night. i'm crazy to see that girl." the big business man rose and went over to a dinner-tray, standing near the door. "lord, i'm hungry. i must have forgotten to eat to-day." he lifted up one of the silver covers. what he saw evidently encouraged him, for he drew up a chair and began his lunch. the very young man lighted a cigarette. "it will be the tragedy of my life," he said, "if he never comes back." the big business man smiled. "how about _his_ life?" he answered, but the very young man had fallen into a reverie and did not reply. the big business man finished his lunch in silence and was just about to light a cigar when a sharp exclamation brought him hastily to his feet. "come here, quick, i see something." the very young man had his face close to the ring and was trembling violently. the other pushed him back. "let me see. where?" "there, by the scratch; he's lying there; i can see him." the big business man looked and then hurriedly woke the doctor. "he's come back," he said briefly; "you can see him there." the doctor bent down over the ring while the others woke up the banker. "he doesn't seem to be getting any bigger," said the very young man; "he's just lying there. maybe he's dead." "what shall we do?" asked the big business man, and made as if to pick up the ring. the doctor shoved him away. "don't do that!" he said sharply. "do you want to kill him?" "he's sitting up," cried the very young man. "he's all right." "he must have fainted," said the doctor. "probably he's taking more of the drug now." "he's much larger," said the very young man; "look at him!" the tiny figure was sitting sideways on the ring, with its feet hanging over the outer edge. it was growing perceptibly larger each instant, and in a moment it slipped down off the ring and sank in a heap on the handkerchief. "good heavens! look at him!" cried the big business man. "he's all covered with blood." the little figure presented a ghastly sight. as it steadily grew larger they could see and recognize the chemist's haggard face, his cheek and neck stained with blood, and his white suit covered with dirt. "look at his feet," whispered the big business man. they were horribly cut and bruised and greatly swollen. the doctor bent over and whispered gently, "what can i do to help you?" the chemist shook his head. his body, lying prone upon the handkerchief, had torn it apart in growing. when he was about twelve inches in length he raised his head. the doctor bent closer. "some brandy, please," said a wraith of the chemist's voice. it was barely audible. "he wants some brandy," called the doctor. the very young man looked hastily around, then opened the door and dashed madly out of the room. when he returned, the chemist had grown to nearly four feet. he was sitting on the floor with his back against the doctor's knees. the big business man was wiping the blood off his face with a damp napkin. "here!" cried the very young man, thrusting forth the brandy. the chemist drank a little of it. then he sat up, evidently somewhat revived. "i seem to have stopped growing," he said. "let's finish it up now. god! how i want to be the right size again," he added fervently. the doctor helped him extract the vials from under his arm, and the chemist touched one of the pills to his tongue. then he sank back, closing his eyes. "i think that should be about enough," he murmured. no one spoke for nearly ten minutes. gradually the chemist's body grew, the doctor shifting his position several times as it became larger. it seemed finally to have stopped growing, and was apparently nearly its former size. "is he asleep?" whispered the very young man. the chemist opened his eyes. "no," he answered. "i'm all right now, i think." he rose to his feet, the doctor and the big business man supporting him on either side. "sit down and tell us about it," said the very young man. "did you find the girl?" the chemist smiled wearily. "gentlemen, i cannot talk now. let me have a bath and some dinner. then i will tell you all about it." the doctor rang for an attendant, and led the chemist to the door, throwing a blanket around him as he did so. in the doorway the chemist paused and looked back with a wan smile over the wreck of the room. "give me an hour," he said. "and eat something yourselves while i am gone." then he left, closing the door after him. when he returned, fully dressed in clothes that were ludicrously large for him, the room had been straightened up, and his four friends were finishing their meal. he took his place among them quietly and lighted a cigar. "well, gentlemen, i suppose that you are interested to hear what happened to me," he began. the very young man asked his usual question. "let him alone," said the doctor. "you will hear it all soon enough." "was it all as you expected?" asked the banker. it was his first remark since the chemist returned. "to a great extent, yes," answered the chemist. "but i had better tell you just what happened." the very young man nodded his eager agreement. "when i took those first four pills," began the chemist in a quiet, even tone, "my immediate sensation was a sudden reeling of the senses, combined with an extreme nausea. this latter feeling passed after a moment. "you will remember that i seated myself upon the floor and closed my eyes. when i opened them my head had steadied itself somewhat, but i was oppressed by a curious feeling of drowsiness, impossible to shake off. "my first mental impression was one of wonderment when i saw you all begin to increase in size. i remember standing up beside that chair, which was then half again its normal size, and you"--indicating the doctor--"towered beside me as a giant of nine or ten feet high. "steadily upward, with a curious crawling motion, grew the room and all its contents. except for the feeling of sleep that oppressed me, i felt quite my usual self. no change appeared happening to me, but everything else seemed growing to gigantic and terrifying proportions. "can you imagine a human being a hundred feet high? that is how you looked to me as i stepped upon that huge expanse of black silk and shouted my last good-bye to you! "over to my left lay the ring, apparently fifteen or twenty feet away. i started to walk towards it, but although it grew rapidly larger, the distance separating me from it seemed to increase rather than lessen. then i ran, and by the time i arrived it stood higher than my waist--a beautiful, shaggy, golden pit. "i jumped upon its rim and clung to it tightly. i could feel it growing beneath me, as i sat. after a moment i climbed upon its top surface and started to walk towards the point where i knew the scratch to be. "i found myself now, as i looked about, walking upon a narrow, though ever broadening, curved path. the ground beneath my feet appeared to be a rough, yellowish quartz. this path grew rougher as i advanced. below the bulging edges of the path, on both sides, lay a shining black plain, ridged and indented, and with a sunlike sheen on the higher portions of the ridges. on the one hand this black plain stretched in an unbroken expanse to the horizon. on the other, it appeared as a circular valley, enclosed by a shining yellow wall. "the way had now become extraordinarily rough. i bore to the left as i advanced, keeping close to the outer edge. the other edge of the path i could not see. i clambered along hastily, and after a few moments was confronted by a row of rocks and bowlders lying directly across my line of progress. i followed their course for a short distance, and finally found a space through which i could pass. "this transverse ridge was perhaps a hundred feet deep. behind it and extending in a parallel direction lay a tremendous valley. i knew then i had reached my first objective. "i sat down upon the brink of the precipice and watched the cavern growing ever wider and deeper. then i realized that i must begin my descent if ever i was to reach the bottom. for perhaps six hours i climbed steadily downwards. it was a fairly easy descent after the first little while, for the ground seemed to open up before me as i advanced, changing its contour so constantly that i was never at a loss for an easy downward path. "my feet suffered cruelly from the shaggy, metallic ground, and i soon had to stop and rig a sort of protection for the soles of them from a portion of the harness over my shoulder. according to the stature i was when i reached the bottom, i had descended perhaps twelve thousand feet during this time. "the latter part of the journey found me nearing the bottom of the cañon. objects around me no longer seemed to increase in size, as had been constantly the case before, and i reasoned that probably my stature was remaining constant. "i noticed, too, as i advanced, a curious alteration in the form of light around me. the glare from above (the sky showed only as a narrow dull ribbon of blue) barely penetrated to the depths of the cañon's floor. but all about me there was a soft radiance, seeming to emanate from the rocks themselves. "the sides of the cañon were shaggy and rough, beyond anything i had ever seen. huge bowlders, hundreds of feet in diameter, were embedded in them. the bottom also was strewn with similar gigantic rocks. "i surveyed this lonely waste for some time in dismay, not knowing in what direction lay my goal. i knew that i was at the bottom of the scratch, and by the comparison of its size i realized i was well started on my journey. "i have not told you, gentlemen, that at the time i marked the ring i made a deeper indentation in one portion of the scratch and focused the microscope upon that. this indentation i now searched for. luckily i found it, less than half a mile away--an almost circular pit, perhaps five miles in diameter, with shining walls extending downwards into blackness. there seemed no possible way of descending into it, so i sat down near its edge to think out my plan of action. "i realized now that i was faint and hungry, and whatever i did must be done quickly. i could turn back to you, or i could go on. i decided to risk the latter course, and took twelve more of the pills--three times my original dose." the chemist paused for a moment, but his auditors were much too intent to question him. then he resumed in his former matter-of-fact tone. "after my vertigo had passed somewhat--it was much more severe this time--i looked up and found my surroundings growing at a far more rapid rate than before. i staggered to the edge of the pit. it was opening up and widening out at an astounding rate. already its sides were becoming rough and broken, and i saw many places where a descent would be possible. "the feeling of sleep that had formerly merely oppressed me, combined now with my physical fatigue and the larger dose of the drug i had taken, became almost intolerable. i yielded to it for a moment, lying down on a crag near the edge of the pit. i must have become almost immediately unconscious, and remained so for a considerable time. i can remember a horrible sensation of sliding headlong for what seemed like hours. i felt that i was sliding or falling downward. i tried to rouse but could not. then came absolute oblivion. "when i recovered my senses i was lying partly covered by a mass of smooth, shining pebbles. i was bruised and battered from head to foot--in a far worse condition than you first saw me when i returned. "i sat up and looked around. beside me, sloped upward at an apparently increasing angle a tremendous glossy plane. this extended, as far as i could see, both to the right and left and upward into the blackness of the sky overhead. it was this plane that had evidently broken my fall, and i had been sliding down it, bringing with me a considerable mass of rocks and bowlders. "as my senses became clearer i saw i was lying on a fairly level floor. i could see perhaps two miles in each direction. beyond that there was only darkness. the sky overhead was unbroken by stars or light of any kind. i should have been in total darkness except, as i have told you before, that everything, even the blackness itself, seemed to be self-luminous. "the incline down which i had fallen was composed of some smooth substance suggesting black marble. the floor underfoot was quite different--more of a metallic quality with a curious corrugation. before me, in the dim distance, i could just make out a tiny range of hills. "i rose, after a time, and started weakly to walk towards these hills. though i was faint and dizzy from my fall and the lack of food, i walked for perhaps half an hour, following closely the edge of the incline. no change in my visual surroundings occurred, except that i seemed gradually to be approaching the line of hills. my situation at this time, as i turned it over in my mind, appeared hopelessly desperate, and i admit i neither expected to reach my destination nor to be able to return to my own world. "a sudden change in the feeling of the ground underfoot brought me to myself; i bent down and found i was treading on vegetation--a tiny forest extending for quite a distance in front and to the side of me. a few steps ahead a little silver ribbon threaded its way through the trees. this i judged to be water. "new hope possessed me at this discovery. i sat down at once and took a portion of another of the pills. "i must again have fallen asleep. when i awoke, somewhat refreshed, i found myself lying beside the huge trunk of a fallen tree. i was in what had evidently once been a deep forest, but which now was almost utterly desolated. only here and there were the trees left standing. for the most part they were lying in a crushed and tangled mass, many of them partially embedded in the ground. "i cannot express adequately to you, gentlemen, what an evidence of tremendous superhuman power this scene presented. no storm, no lightning, nor any attack of the elements could have produced more than a fraction of the destruction i saw all around me. "i climbed cautiously upon the fallen tree-trunk, and from this elevation had a much better view of my surroundings. i appeared to be near one end of the desolated area, which extended in a path about half a mile wide and several miles deep. in front, a thousand feet away, perhaps, lay the unbroken forest. "descending from the tree-trunk i walked in this direction, reaching the edge of the woods after possibly an hour of the most arduous traveling of my whole journey. "during this time almost my only thought was the necessity of obtaining food. i looked about me as i advanced, and on one of the fallen tree-trunks i found a sort of vine growing. this vine bore a profusion of small gray berries, much like our huckleberries. they proved similar in taste, and i sat down and ate a quantity. "when i reached the edge of the forest i felt somewhat stronger. i had seen up to this time no sign of animal life whatever. now, as i stood silent, i could hear around me all the multitudinous tiny voices of the woods. insect life stirred underfoot, and in the trees above an occasional bird flitted to and fro. "perhaps i am giving you a picture of our own world. i do not mean to do so. you must remember that above me there was no sky, just blackness. and yet so much light illuminated the scene that i could not believe it was other than what we would call daytime. objects in the forest were as well lighted--better probably than they would be under similar circumstances in our own world. "the trees were of huge size compared to my present stature; straight, upstanding trunks, with no branches until very near the top. they were bluish-gray in color, and many of them well covered with the berry-vine i have mentioned. the leaves overhead seemed to be blue--in fact the predominating color of all the vegetation was blue, just as in our world it is green. the ground was covered with dead leaves, mould, and a sort of gray moss. fungus of a similar color appeared, but of this i did not eat. "i had penetrated perhaps two miles into the forest when i came unexpectedly to the bank of a broad, smooth-flowing river, its silver surface seeming to radiate waves of the characteristic phosphorescent light. i found it cold, pure-tasting water, and i drank long and deeply. then i remember lying down upon the mossy bank, and in a moment, utterly worn out, i again fell asleep." chapter iv lylda "i was awakened by the feel of soft hands upon my head and face. with a start i sat up abruptly; i rubbed my eyes confusedly for a moment, not knowing where i was. when i collected my wits i found myself staring into the face of a girl, who was kneeling on the ground before me. i recognized her at once--she was the girl of the microscope. "to say i was startled would be to put it mildly, but i read no fear in her expression, only wonderment at my springing so suddenly into life. she was dressed very much as i had seen her before. her fragile beauty was the same, and at this closer view infinitely more appealing, but i was puzzled to account for her older, more mature look. she seemed to have aged several years since the last evening i had seen her through the microscope. yet, undeniably, it was the same girl. "for some moments we sat looking at each other in wonderment. then she smiled and held out her hand, palm up, speaking a few words as she did so. her voice was soft and musical, and the words of a peculiar quality that we generally describe as liquid, for want of a better term. what she said was wholly unintelligible, but whether the words were strange or the intonation different from anything i had ever heard i could not determine. "afterwards, during my stay in this other world, i found that the language of its people resembled english quite closely, so far as the words themselves went. but the intonation with which they were given, and the gestures accompanying them, differed so widely from our own that they conveyed no meaning. "the gap separating us, however, was very much less than you would imagine. strangely enough, though, it was not i who learned to speak her tongue, but she who mastered mine." the very young man sighed contentedly. "we became quite friendly after this greeting," resumed the chemist, "and it was apparent from her manner that she had already conceived her own idea of who and what i was. "for some time we sat and tried to communicate with each other. my words seemed almost as unintelligible to her as hers to me, except that occasionally she would divine my meaning, clapping her hands in childish delight. i made out that she lived at a considerable distance, and that her name was lylda. finally she pulled me by the hand and led me away with a proprietary air that amused and, i must admit, pleased me tremendously. "we had progressed through the woods in this way, hardly more than a few hundred yards, when suddenly i found that she was taking me into the mouth of a cave or passageway, sloping downward at an angle of perhaps twenty degrees. i noticed now, more graphically than ever before, a truth that had been gradually forcing itself upon me. darkness was impossible in this new world. we were now shut in between narrow walls of crystalline rock, with a roof hardly more than fifty feet above. "no artificial light of any kind was in evidence, yet the scene was lighted quite brightly. this, i have explained, was caused by the phosphorescent radiation that apparently emanated from every particle of mineral matter in this universe. "as we advanced, many other tunnels crossed the one we were traveling. and now, occasionally, we passed other people, the men dressed similarly to lylda, but wearing their hair chopped off just above the shoulder line. "later, i found that the men were generally about five and a half feet in stature: lean, muscular, and with a grayer, harder look to their skin than the iridescent quality that characterized the women. "they were fine-looking chaps these we encountered. all of them stared curiously at me, and several times we were held up by chattering groups. the intense whiteness of my skin, for it looked in this light the color of chalk, seemed to both awe and amuse them. but they treated me with great deference and respect, which i afterwards learned was because of lylda herself, and also what she told them about me. "at several of the intersections of the tunnels there were wide open spaces. one of these we now approached. it was a vast amphitheater, so broad its opposite wall was invisible, and it seemed crowded with people. at the side, on a rocky niche in the wall, a speaker harangued the crowd. "we skirted the edge of this crowd and plunged into another passageway, sloping downward still more steeply. i was so much interested in the strange scenes opening before me that i remarked little of the distance we traveled. nor did i question lylda but seldom. i was absorbed in the complete similarity between this and my own world in its general characteristics, and yet its complete strangeness in details. "i felt not the slightest fear. indeed the sincerity and kindliness of these people seemed absolutely genuine, and the friendly, naïve, manner of my little guide put me wholly at my ease. towards me lylda's manner was one of childish delight at a new-found possession. towards those of her own people with whom we talked, i found she preserved a dignity they profoundly respected. "we had hardly more than entered this last tunnel when i heard the sound of drums and a weird sort of piping music, followed by shouts and cheers. figures from behind us scurried past, hastening towards the sound. lylda's clasp on my hand tightened, and she pulled me forward eagerly. as we advanced the crowd became denser, pushing and shoving us about and paying little attention to me. "in close contact with these people i soon found i was stronger than they, and for a time i had no difficulty in shoving them aside and opening a path for us. they took my rough handling in all good part, in fact, never have i met a more even-tempered, good-natured people than these. "after a time the crowd became so dense we could advance no further. at this lylda signed me to bear to the side. as we approached the wall of the cavern she suddenly clasped her hands high over her head and shouted something in a clear, commanding voice. instantly the crowd fell back, and in a moment i found myself being pulled up a narrow flight of stone steps in the wall and out upon a level space some twenty feet above the heads of the people. "several dignitaries occupied this platform. lylda greeted them quietly, and they made place for us beside the parapet. i could see now that we were at the intersection of a transverse passageway, much broader than the one we had been traversing. and now i received the greatest surprise i had had in this new world, for down this latter tunnel was passing a broad line of men who obviously were soldiers. "the uniformly straight lines they held; the glint of light on the spears they carried upright before them; the weird, but rhythmic, music that passed at intervals, with which they kept step; and, above all, the cheering enthusiasm of the crowd, all seemed like an echo of my own great world above. "this martial ardor and what it implied came as a distinct shock. all i had seen before showed the gentle kindliness of a people whose life seemed far removed from the struggle for existence to which our race is subjected. i had come gradually to feel that this new world, at least, had attained the golden age of security, and that fear, hate, and wrongdoing had long since passed away, or had never been born. "yet, here before my very eyes, made wholesome by the fires of patriotism, stalked the grim god of war. knowing nothing yet of the motive that inspired these people, i could feel no enthusiasm, but only disillusionment at this discovery of the omnipotence of strife. "for some time i must have stood in silence. lylda, too, seemed to divine my thoughts, for she did not applaud, but pensively watched the cheering throng below. all at once, with an impulsively appealing movement, she pulled me down towards her, and pressed her pretty cheek to mine. it seemed almost as if she was asking me to help. "the line of marching men seemed now to have passed, and the crowd surged over into the open space and began to disperse. as the men upon the platform with us prepared to leave, lylda led me over to one of them. he was nearly as tall as i, and dressed in the characteristic tunic that seemed universally worn by both sexes. the upper part of his body was hung with beads, and across his chest was a thin, slightly convex stone plate. "after a few words of explanation from lylda, he laid his hands on my shoulders near the base of the neck, smiling with his words of greeting. then he held one hand before me, palm up, as lylda had done, and i laid mine in it, which seemed the correct thing to do. "i repeated this performance with two others who joined us, and then lylda pulled me away. we descended the steps and turned into the broader tunnel, finding near at hand a sort of sleigh, which lylda signed me to enter. it was constructed evidently of wood, with a pile of leaves, or similar dead vegetation, for cushions. it was balanced upon a single runner of polished stone, about two feet broad, with a narrow, slightly shorter outrider on each side. "harnessed to the shaft were two animals, more resembling our reindeers than anything else, except that they were gray in color and had no horns. an attendant greeted lylda respectfully as we approached, and mounted a seat in front of us when we were comfortably settled. "we drove in this curious vehicle for over an hour. the floor of the tunnel was quite smooth, and we glided down its incline with little effort and at a good rate. our driver preserved the balance of the sleigh by shifting his body from side to side so that only at rare intervals did the siderunners touch the ground. "finally, we emerged into the open, and i found myself viewing a scene of almost normal, earthly aspect. we were near the shore of a smooth, shining lake. at the side a broad stretch of rolling country, dotted here and there with trees, was visible. near at hand, on the lake shore, i saw a collection of houses, most of them low and flat, with one much larger on a promontory near the lake. "overhead arched a gray-blue, cloudless sky, faintly star-studded, and reflected in the lake before me i saw that familiar gleaming trail of star-dust, hanging like a huge straightened rainbow overhead, and ending at my feet." chapter v the world in the ring the chemist paused and relighted his cigar. "perhaps you have some questions," he suggested. the doctor shifted in his chair. "did you have any theory at this time"--he wanted to know--"about the physical conformation of this world? what i mean is, when you came out of this tunnel were you on the inside or the outside of the world?" "was it the same sky you saw overhead when you were in the forest?" asked the big business man. "no, it was what he saw in the microscope, wasn't it?" said the very young man. "one at a time, gentlemen," laughed the chemist. "no, i had no particular theory at this time--i had too many other things to think of. but i do remember noticing one thing which gave me the clew to a fairly complete understanding of this universe. from it i formed a definite explanation, which i found was the belief held by the people themselves." "what was that?" asked the very young man. "i noticed, as i stood looking over this broad expanse of country before me, one vital thing that made it different from any similar scene i had ever beheld. if you will stop and think a moment, gentlemen, you will realize that in our world here the horizon is caused by a curvature of the earth below the straight line of vision. we are on a convex surface. but as i gazed over this landscape, and even with no appreciable light from the sky i could see a distance of several miles, i saw at once that quite the reverse was true. i seemed to be standing in the center of a vast shallow bowl. the ground curved upward into the distance. there was no distant horizon line, only the gradual fading into shadow of the visual landscape. i was standing obviously on a concave surface, on the inside, not the outside of the world. "the situation, as i now understand it, was this: according to the smallest stature i reached, and calling my height at that time roughly six feet, i had descended into the ring at the time i met lylda several thousand miles, at least. by the way, where is the ring?" "here is it," said the very young man, handing it to him. the chemist replaced it on his finger. "it's pretty important to me now," he said, smiling. "you bet!" agreed the very young man. "you can readily understand how i descended such a distance, if you consider the comparative immensity of my stature during the first few hours i was in the ring. it is my understanding that this country through which i passed is a barren waste--merely the atoms of the mineral we call gold. "beyond that i entered the hitherto unexplored regions within the atom. the country at that point where i found the forest, i was told later, is habitable for several hundred miles. around it on all sides lies a desert, across which no one has ever penetrated. "this surface is the outside of the oroid world, for so they call their earth. at this point the shell between the outer and inner surface is only a few miles in thickness. the two surfaces do not parallel each other here, so that in descending these tunnels we turned hardly more than an eighth of a complete circle. "at the city of arite, where lylda first took me, and where i had my first view of the inner surface, the curvature is slightly greater than that of our own earth, although, as i have said, in the opposite direction." "and the space within this curvature--the heavens you have mentioned--how great do you estimate it to be?" asked the doctor. "based on the curvature at arite it would be about six thousand miles in diameter." "has this entire inner surface been explored?" asked the big business man. "no, only a small portion. the oroids are not an adventurous people. there are only two nations, less than twelve million people all together, on a surface nearly as extensive as our own." "how about those stars?" suggested the very young man. "i believe they comprise a complete universe similar to our own solar system. there is a central sun-star, around which many of the others revolve. you must understand, though, that these other worlds are infinitely tiny compared to the oroids, and, if inhabited, support beings nearly as much smaller than the oroids, as they are smaller than you." "great caesar!" ejaculated the banker. "don't let's go into that any deeper!" "tell us more about lylda," prompted the very young man. "you are insatiable on that point," laughed the chemist. "well, when we left the sleigh, lylda took me directly into the city of arite. i found it an orderly collection of low houses, seemingly built of uniformly cut, highly polished gray blocks. as we passed through the streets, some of which were paved with similar blocks, i was reminded of nothing so much as the old jingles of spotless town. everything was immaculately, inordinately clean. indeed, the whole city seemed built of some curious form of opaque glass, newly scrubbed and polished. "children crowded from the doorways as we advanced, but lylda dispersed them with a gentle though firm, command. as we approached the sort of castle i have mentioned, the reason for lylda's authoritative manner dawned upon me. she was, i soon learned, daughter of one of the most learned men of the nation and was--handmaiden, do you call it?--to the queen." "so it was a monarchy?" interrupted the big business man. "i should never have thought that." "lylda called their leader a king. in reality he was the president, chosen by the people, for a period of about what we would term twenty years; i learned something about this republic during my stay, but not as much as i would have liked. politics was not lylda's strong point, and i had to get it all from her, you know. "for several days i was housed royally in the castle. food was served me by an attendant who evidently was assigned solely to look after my needs. at first i was terribly confused by the constant, uniform light, but when i found certain hours set aside for sleep, just as we have them, when i began to eat regularly, i soon fell into the routine of this new life. "the food was not greatly different from our own, although i found not a single article i could identify. it consisted principally of vegetables and fruits, the latter of an apparently inexhaustible variety. "lylda visited me at intervals, and i learned i was awaiting an audience with the king. during these days she made rapid progress with my language--so rapid that i shortly gave up the idea of mastering hers. "and now, with the growing intimacy between us and our ability to communicate more readily, i learned the simple, tragic story of her race--new details, of course, but the old, old tale of might against right, and the tragedy of a trusting, kindly people, blindly thinking others as just as themselves. "for thousands of years, since the master life-giver had come from one of the stars to populate the world, the oroid nation had dwelt in peace and security. these people cared nothing for adventure. no restless thirst for knowledge led them to explore deeply the limitless land surrounding them. even from the earliest times no struggle for existence, no doctrine of the survival of the fittest, hung over them as with us. no wild animals harassed them; no savages menaced them. a fertile boundless land, a perfect climate, nurtured them tenderly. "under such conditions they developed only the softer, gentler qualities of nature. many laws among them were unnecessary, for life was so simple, so pleasant to live, and the attainment of all the commonly accepted standards of wealth so easy, that the incentive to wrongdoing was almost non-existent. "strangely enough, and fortunately, too, no individuals rose among them with the desire for power. those in command were respected and loved as true workers for the people, and they accepted their authority in the same spirit with which it was given. indolence, in its highest sense the wonderful art of doing nothing gracefully, played the greatest part in their life. "then, after centuries of ease and peaceful security, came the awakening. almost without warning another nation had come out of the unknown to attack them. "with the hurt feeling that comes to a child unjustly treated, they all but succumbed to this first onslaught. the abduction of numbers of their women, for such seemed the principal purpose of the invaders, aroused them sufficiently to repel this first crude attack. their manhood challenged, their anger as a nation awakened for the first time, they sprang as one man into the horror we call war. "with the defeat of the malites came another period of ease and security. they had learned no lesson, but went their indolent way, playing through life like the kindly children they were. during this last period some intercourse between them and the malites took place. the latter people, whose origin was probably nearly opposite them on the inner surface, had by degrees pushed their frontiers closer and closer to the oroids. trade between the two was carried on to some extent, but the character of the malites, their instinctive desire for power, for its own sake, their consideration for themselves as superior beings, caused them to be distrusted and feared by their more simple-minded companion nation. "you can almost guess the rest, gentlemen. lylda told me little about the malites, but the loathing disgust of her manner, her hesitancy, even to bring herself to mention them, spoke more eloquently than words. "four years ago, as they measure time, came the second attack, and now, in a huge arc, only a few hundred miles from arite, hung the opposing armies." the chemist paused. "that's the condition i found, gentlemen," he said. "not a strikingly original or unfamiliar situation, was it?" "by jove!" remarked the doctor thoughtfully, "what a curious thing that the environment of our earth should so affect that world inside the ring. it does make you stop and think, doesn't it, to realize how those infinitesimal creatures are actuated now by the identical motives that inspire us?" "yet it does seem very reasonable, i should say," the big business man put in. "let's have another round of drinks," suggested the banker--"this is dry work!" "as a scientist you'd make a magnificent plumber, george!" retorted the big business man. "you're about as helpful in this little gathering as an oyster!" the very young man rang for a waiter. "i've been thinking----" began the banker, and stopped at the smile of his companion. "shut up!"--he finished--"that's cheap wit, you know!" "go on, george," encouraged the other, "you've been thinking----" "i've been tremendously interested in this extraordinary story"--he addressed himself to the chemist--"but there's one point i don't get at all. how many days were you in that ring do you make out?" "i believe about seven, all told," returned the chemist. "but you were only away from us some forty hours. i ought to know, i've been right here." he looked at his crumpled clothes somewhat ruefully. "the change of time-progress was one of the surprises of my adventure," said the chemist. "it is easily explained in a general way, although i cannot even attempt a scientific theory of its cause. but i must confess that before i started the possibility of such a thing never even occurred to me." "to get a conception of this change you must analyze definitely what time is. we measure and mark it by years, months, and so forth, down to minutes and seconds, all based upon the movements of our earth around its sun. but that is the measurement of time, not time itself. how would you describe time?" the big business man smiled. "time," he said, "is what keeps everything from happening at once." "very clever," laughed the chemist. the doctor leaned forward earnestly. "i should say," he began, "that time is the rate at which we live--the speed at which we successively pass through our existence from birth to death. it's very hard to put intelligibly, but i think i know what i mean," he finished somewhat lamely. "exactly so. time is a rate of life-progress, different for every individual and only made standard because we take the time-duration of the earth's revolution around the sun, which is constant, and arbitrarily say: 'that is thirty-one million five hundred thousand odd seconds.'" "is time different for every individual?" asked the banker argumentatively. "think a moment," returned the chemist. "suppose your brain were to work twice as fast as mine. suppose your heart beat twice as fast, and all the functions of your body were accelerated in a like manner. what we call a second would certainly seem to you twice as long. further than that, it actually would be twice as long, so far as you were concerned. your digestion, instead of taking perhaps four hours, would take two. you would eat twice as often. the desire for sleep would overtake you every twelve hours instead of twenty-four, and you would be satisfied with four hours of unconsciousness instead of eight. in short, you would soon be living a cycle of two days every twenty-four hours. time then, as we measure it, for you at least would have doubled--you would be progressing through life at twice the rate that i am through mine." "that may be theoretically true," the big business man put in. "practically, though, it has never happened to any one." "of course not, to such a great degree as the instance i put. no one, except in disease, has ever doubled our average rate of life-progress, and lived it out as a balanced, otherwise normal existence. but there is no question that to some much smaller degree we all of us differ one from the other. the difference, however, is so comparatively slight, that we can each one reconcile it to the standard measurement of time. and so, outwardly, time is the same for all of us. but inwardly, why, we none of us conceive a minute or an hour to be the same! how do you know how long a minute is to me? more than that, time is not constant even in the same individual. how many hours are shorter to you than others? how many days have been almost interminable? no, instead of being constant, there is nothing more inconstant than time." "haven't you confused two different issues?" suggested the big business man. "granted what you say about the slightly different rate at which different individuals live, isn't it quite another thing, how long time seems to you. a day when you have nothing to do seems long, or, on the other hand, if you are very busy it seems short. but mind, it only _seems_ short or long, according to the preoccupation of your mind. that has nothing to do with the speed of your progress through life." "ah, but i think it has," cried the chemist. "you forget that we none of us have all of the one thing to the exclusion of the other. time seems short; it seems long, and in the end it all averages up, and makes our rate of progress what it is. now if any of us were to go through life in a calm, deliberate way, making time seem as long as possible, he would live more years, as we measure them, than if he rushed headlong through the days, accomplishing always as much as possible. i mean in neither case to go to the extremes, but only so far as would be consistent with the maintenance of a normal standard of health. how about it?" he turned to the doctor. "you ought to have an opinion on that." "i rather think you are right," said the latter thoughtfully, "although i doubt very much if the man who took it easy would do as much during his longer life as the other with his energy would accomplish in the lesser time allotted to him." "probably he wouldn't," smiled the chemist; "but that does not alter the point we are discussing." "how does this apply to the world in the ring?" ventured the very young man. "i believe there is a very close relationship between the dimensions of length, breadth, and thickness, and time. just what connection with them it has, i have no idea. yet, when size changes, time-rate changes; you have only to look at our own universe to discover that." "how do you mean?" asked the very young man. "why, all life on our earth, in a general way, illustrates the fundamental fact that the larger a thing is, the slower its time-progress is. an elephant, for example, lives more years than we humans. yet how quickly a fly is born, matured, and aged! there are exceptions, of course; but in a majority of cases it is true. "so i believe that as i diminished in stature, my time-progress became faster and faster. i am seven days older than when i left you day before yesterday. i have lived those seven days, gentlemen, there is no getting around that fact." "this is all tremendously interesting," sighed the big business man; "but not very comprehensible." chapter vi strategy and kisses "it was the morning of my third day in the castle," began the chemist again, "that i was taken by lylda before the king. we found him seated alone in a little anteroom, overlooking a large courtyard, which we could see was crowded with an expectant, waiting throng. i must explain to you now, that i was considered by lylda somewhat in the light of a messiah, come to save her nation from the destruction that threatened it. "she believed me a supernatural being, which, indeed, if you come to think of it, gentlemen, is exactly what i was. i tried to tell her something of myself and the world i had come from, but the difficulties of language and her smiling insistence and faith in her own conception of me, soon caused me to desist. thereafter i let her have her own way, and did not attempt any explanation again for some time. "for several weeks before lylda found me sleeping by the river's edge, she had made almost a daily pilgrimage to that vicinity. a maidenly premonition, a feeling that had first come to her several years before, told her of my coming, and her father's knowledge and scientific beliefs had led her to the outer surface of the world as the direction in which to look. a curious circumstance, gentlemen, lies in the fact that lylda clearly remembered the occasion when this first premonition came to her. and in the telling, she described graphically the scene in the cave, where i saw her through the microscope." the chemist paused an instant and then resumed. "when we entered the presence of the king, he greeted me quietly, and made me sit by his side, while lylda knelt on the floor at our feet. the king impressed me as a man about fifty years of age. he was smooth-shaven, with black, wavy hair, reaching his shoulders. he was dressed in the usual tunic, the upper part of his body covered by a quite similar garment, ornamented with a variety of metal objects. his feet were protected with a sort of buskin; at his side hung a crude-looking metal spear. "the conversation that followed my entrance, lasted perhaps fifteen minutes. lylda interpreted for us as well as she could, though i must confess we were all three at times completely at a loss. but lylda's bright, intelligent little face, and the resourcefulness of her gestures, always managed somehow to convey her meaning. the charm and grace of her manner, all during the talk, her winsomeness, and the almost spiritual kindness and tenderness that characterized her, made me feel that she embodied all those qualities with which we of this earth idealize our own womanhood. "i found myself falling steadily under the spell of her beauty, until--well, gentlemen, it's childish for me to enlarge upon this side of my adventure, you know; but--lylda means everything to me now, and i'm going back for her just as soon as i possibly can." "bully for you!" cried the very young man. "why didn't you bring her with you this time?" "let him tell it his own way," remonstrated the doctor. the very young man subsided with a sigh. "during our talk," resumed the chemist, "i learned from the king that lylda had promised him my assistance in overcoming the enemies that threatened his country. he smilingly told me that our charming little interpreter had assured him i would be able to do this. lylda's blushing face, as she conveyed this meaning to me, was so thoroughly captivating, that before i knew it, and quite without meaning to, i pulled her up towards me and kissed her. "the king was more surprised by far than lylda, at this extraordinary behavior. obviously neither of them had understood what a kiss meant, although lylda, by her manner evidently comprehended pretty thoroughly. "i told them then, as simply as possible to enable lylda to get my meaning, that i could, and would gladly aid in their war. i explained then, that i had the power to change my stature, and could make myself grow very large or very small in a short space of time. "this, as lylda evidently told it to him, seemed quite beyond the king's understanding. he comprehended finally, or at least he agreed to believe my statement. "this led to the consideration of practical questions of how i was to proceed in their war. i had not considered any details before, but now they appeared of the utmost simplicity. all i had to do was to make myself a hundred or two hundred feet high, walk out to the battle-lines, and scatter the opposing army like a set of small boys' playthings." "what a quaint idea!" said the banker. "a modern 'gulliver.'" the chemist did not heed this interruption. "then like three children we plunged into a discussion of exactly how i was to perform these wonders, the king laughing heartily as we pictured the attack on my tiny enemies. "he then asked me how i expected to accomplish this change of size, and i very briefly told him of our larger world, and the manner in which i had come from it into his. then i showed the drugs that i still carried carefully strapped to me. this seemed definitely to convince the king of my sincerity. he rose abruptly to his feet, and strode through a doorway on to a small balcony overlooking the courtyard below. "as he stepped out into the view of the people, a great cheer arose. he waited quietly for them to stop, and then raised his hand and began speaking. lylda and i stood hand in hand in the shadow of the doorway, out of sight of the crowd, but with it and the entire courtyard plainly in our view. "it was a quadrangular enclosure, formed by the four sides of the palace, perhaps three hundred feet across, packed solidly now with people of both sexes, the gleaming whiteness of the upper parts of their bodies, and their upturned faces, making a striking picture. "for perhaps ten minutes the king spoke steadily, save when he was interrupted by applause. then he stopped abruptly and, turning, pulled lylda and me out upon the balcony. the enthusiasm of the crowd doubled at our appearance. i was pushed forward to the balcony rail, where i bowed to the cheering throng. "just after i left the king's balcony, i met lylda's father. he was a kindly-faced old gentleman, and took a great interest in me and my story. he it was who told me about the physical conformation of his world, and he seemed to comprehend my explanation of mine. "that night it rained--a heavy, torrential downpour, such as we have in the tropics. lylda and i had been talking for some time, and, i must confess, i had been making love to her ardently. i broached now the principal object of my entrance into her world, and, with an eloquence i did not believe i possessed, i pictured the wonders of our own great earth above, begging her to come back with me and live out her life with mine. "much of what i said, she probably did not understand, but the main facts were intelligible without question. she listened quietly. when i had finished, and waited for her decision, she reached slowly out and clutched my shoulders, awkwardly making as if to kiss me. in an instant she was in my arms, with a low, happy little cry." chapter vii a modern gulliver "the clattering fall of rain brought us to ourselves. rising to her feet, lylda pulled me over to the window-opening, and together we stood and looked out into the night. the scene before us was beautiful, with a weirdness almost impossible to describe. it was as bright as i had ever seen this world, for even though heavy clouds hung overhead, the light from the stars was never more than a negligible quantity. "we were facing the lake--a shining expanse of silver radiation, its surface shifting and crawling, as though a great undulating blanket of silver mist lay upon it. and coming down to meet it from the sky were innumerable lines of silver--a vast curtain of silver cords that broke apart into great strings of pearls when i followed their downward course. "and then, as i turned to lylda, i was struck with the extraordinary weirdness of her beauty as never before. the reflected light from the rain had something the quality of our moonlight. shining on lylda's body, it tremendously enhanced the iridescence of her skin. and her face, upturned to mine, bore an expression of radiant happiness and peace such as i had never seen before on a woman's countenance." the chemist paused, his voice dying away into silence as he sat lost in thought. then he pulled himself together with a start. "it was a sight, gentlemen, the memory of which i shall cherish all my life. "the next day was that set for my entrance into the war. lylda and i had talked nearly all night, and had decided that she was to return with me to my world. by morning the rain had stopped, and we sat together in the window-opening, silenced with the thrill of the wonderful new joy that had come into our hearts. "the country before us, under the cloudless, starry sky, stretched gray-blue and beautiful into the quivering obscurity of the distance. at our feet lay the city, just awakening into life. beyond, over the rolling meadows and fields, wound the road that led out to the battle-front, and coming back over it now, we could see an endless line of vehicles. these, as they passed through the street beneath our window, i found were loaded with soldiers, wounded and dying. i shuddered at the sight of one cart in particular, and lylda pressed close to me, pleading with her eyes for my help for her stricken people. "my exit from the castle was made quite a ceremony. a band of music and a guard of several hundred soldiers ushered me forth, walking beside the king, with lylda a few paces behind. as we passed through the streets of the city, heading for the open country beyond, we were cheered continually by the people who thronged the streets and crowded upon the housetops to watch us pass. "outside arite i was taken perhaps a mile, where a wide stretch of country gave me the necessary space for my growth. we were standing upon a slight hill, below which, in a vast semicircle, fully a hundred thousand people were watching. "and now, for the first time, fear overcame me. i realized my situation--saw myself in a detached sort of way--a stranger in this extraordinary world, and only the power of my drug to raise me out of it. this drug you must remember, i had not as yet taken. suppose it were not to act? or were to act wrongly? "i glanced around. the king stood before me, quietly waiting my pleasure. then i turned to lylda. one glance at her proud, happy little face, and my fear left me as suddenly as it had come. i took her in my arms and kissed her, there before that multitude. then i set her down, and signified to the king i was ready. "i took a minute quantity of one of the drugs, and as i had done before, sat down with my eyes covered. my sensations were fairly similar to those i have already described. when i looked up after a moment, i found the landscape dwindling to tiny proportions in quite as astonishing a way as it had grown before. the king and lylda stood now hardly above my ankle. "a great cry arose from the people--a cry wherein horror, fear, and applause seemed equally mixed. i looked down and saw thousands of them running away in terror. "still smaller grew everything within my vision, and then, after a moment, the landscape seemed at rest. i kneeled now upon the ground, carefully, to avoid treading on any of the people around me. i located lylda and the king after a moment; tiny little creatures less than an inch in height. i was then, i estimated, from their viewpoint, about four hundred feet tall. "i put my hand flat upon the ground near lylda, and after a moment she climbed into it, two soldiers lifting her up the side of my thumb as it lay upon the ground. in the hollow of my palm, she lay quite securely, and very carefully i raised her up towards my face. then, seeing that she was frightened, i set her down again. "at my feet, hardly more than a few steps away, lay the tiny city of arite and the lake. i could see all around the latter now, and could make out clearly a line of hills on the other side. off to the left the road wound up out of sight in the distance. as far as i could see, a line of soldiers was passing out along this road--marching four abreast, with carts at intervals, loaded evidently with supplies; only occasionally, now, vehicles passed in the other direction. can i make it plain to you, gentlemen, my sensations in changing stature? i felt at first as though i were tremendously high in the air, looking down as from a balloon upon the familiar territory beneath me. that feeling passed after a few moments, and i found that my point of view had changed. i no longer felt that i was looking down from a balloon, but felt as a normal person feels. and again i conceived myself but six feet tall, standing above a dainty little toy world. it is all in the viewpoint, of course, and never, during all my changes, was i for more than a moment able to feel of a different stature than i am at this present instant. it was always everything else that changed. "according to the directions i had received from the king, i started now to follow the course of the road. i found it difficult walking, for the country was dotted with houses, trees, and cultivated fields, and each footstep was a separate problem. "i progressed in this manner perhaps two miles, covering what the day before i would have called about a hundred and thirty or forty miles. the country became wilder as i advanced, and now was in places crowded with separate collections of troops. "i have not mentioned the commotion i made in this walk over the country. my coming must have been told widely by couriers the night before, to soldiers and peasantry alike, or the sight of me would have caused utter demoralization. as it was, i must have been terrifying to a tremendous degree. i think the careful way in which i picked my course, stepping in the open as much as possible, helped to reassure the people. behind me, whenever i turned, they seemed rather more curious than fearful, and once or twice when i stopped for a few moments they approached my feet closely. one athletic young soldier caught the loose end of the string of one of my buskins, as it hung over my instep close to the ground and pulled himself up hand over hand, amid the enthusiastic cheers of his comrades. "i had walked nearly another mile, when almost in front of me, and perhaps a hundred yards away, i saw a remarkable sight that i did not at first understand. the country here was crossed by a winding river running in a general way at right angles to my line of progress. at the right, near at hand, and on the nearer bank of the river, lay a little city, perhaps half the size of arite, with its back up against a hill. "what first attracted my attention was that from a dark patch across the river which seemed to be woods, pebbles appeared to pop up at intervals, traversing a little arc perhaps as high as my knees, and falling into the city. i watched for a moment and then i understood. there was a siege in progress, and the catapults of the malites were bombarding the city with rocks. "i went up a few steps closer, and the pebbles stopped coming. i stood now beside the city, and as i bent over it, i could see by the battered houses the havoc the bombardment had caused. inert little figures lay in the streets, and i bent lower and inserted my thumb and forefinger between a row of houses and picked one up. it was the body of a woman, partly mashed. i set it down again hastily. "then as i stood up, i felt a sting on my leg. a pebble had hit me on the shin and dropped at my feet. i picked it up. it was the size of a small walnut--a huge bowlder six feet or more in diameter it would have been in lylda's eyes. at the thought of her i was struck with a sudden fit of anger. i flung the pebble violently down into the wooded patch and leaped over the river in one bound, landing squarely on both feet in the woods. it was like jumping into a patch of ferns. "i stamped about me for a moment until a large part of the woods was crushed down. then i bent over and poked around with my finger. underneath the tangled wreckage of tiny-tree trunks, lay numbers of the malites. i must have trodden upon a thousand or more, as one would stamp upon insects. "the sight sickened me at first, for after all, i could not look upon them as other than men, even though they were only the length of my thumb-nail. i walked a few steps forward, and in all directions i could see swarms of the little creatures running. then the memory of my coming departure from this world with lylda, and my promise to the king to rid his land once for all from these people, made me feel again that they, like vermin, were to be destroyed. "without looking directly down, i spent the next two hours stamping over this entire vicinity. then i ran two or three miles directly toward the country of the malites, and returning i stamped along the course of the river for a mile or so in both directions. then i walked back to arite, again picking my way carefully among crowds of oroids, who now feared me so little that i had difficulty in moving without stepping upon them. "when i had regained my former size, which needed two successive doses of the drug, i found myself surrounded by a crowd of the oroids, pushing and shoving each other in an effort to get closer to me. the news of my success over their enemy have been divined by them, evidently. lord knows it must have been obvious enough what i was going to do, when they saw me stride away, a being four hundred feet tall. "their enthusiasm and thankfulness now were so mixed with awe and reverent worship of me as a divine being, that when i advanced towards arite they opened a path immediately. the king, accompanied by lylda, met me at the edge of the city. the latter threw herself into my arms at once, crying with relief to find me the proper size once more. "i need not go into details of the ceremonies of rejoicing that took place this afternoon. these people seemed little given to pomp and public demonstration. the king made a speech from his balcony, telling them all i had done, and the city was given over to festivities and preparations to receive the returning soldiers." the chemist pushed his chair back from the table, and moistened his dry lips with a swallow of water. "i tell you, gentlemen," he continued, "i felt pretty happy that day. it's a wonderful feeling to find yourself the savior of a nation." at that the doctor jumped to his feet, overturning his chair, and striking the table a blow with his fist that made the glasses dance. "by god!" he fairly shouted, "that's just what you can be here to us." the banker looked startled, while the very young man pulled the chemist by the coat in his eagerness to be heard. "a few of those pills," he said in a voice that quivered with excitement, "when you are standing in france, and you can walk over to berlin and kick the houses apart with the toe of your boot." "why not?" said the big business man, and silence fell on the group as they stared at each other, awed by the possibilities that opened up before them. chapter viii "i must go back" the tremendous plan for the salvation of their own suffering world through the chemist's discovery occupied the five friends for some time. then laying aside this subject, that now had become of the most vital importance to them all, the chemist resumed his narrative. "my last evening in the world of the ring, i spent with lylda, discussing our future, and making plans for the journey. i must tell you now, gentlemen, that never for a moment during my stay in arite was i once free from an awful dread of this return trip. i tried to conceive what it would be like, and the more i thought about it, the more hazardous it seemed. "you must realize, when i was growing smaller, coming in, i was able to climb down, or fall or slide down, into the spaces as they opened up. going back, i could only imagine the world as closing in upon me, crushing me to death unless i could find a larger space immediately above into which i could climb. "and as i talked with lylda about this and tried to make her understand what i hardly understood myself, i gradually was brought to realize the full gravity of the danger confronting us. if only i had made the trip out once before, i could have ventured it with her. but as i looked at her fragile little body, to expose it to the terrible possibilities of such a journey was unthinkable. "there was another question, too, that troubled me. i had been gone from you nearly a week, and you were only to wait for me two days. i believed firmly that i was living at a faster rate, and that probably my time with you had not expired. but i did not know. and suppose, when i had come out on to the surface of the ring, one of you had had it on his finger walking along the street? no, i did not want lylda with me in that event. "and so i told her--made her understand--that she must stay behind, and that i would come back for her. she did not protest. she said nothing--just looked up into my face with wide, staring eyes and a little quiver of her lips. then she clutched my hand and fell into a low, sobbing cry. "i held her in my arms for a few moments, so little, so delicate, so human in her sorrow, and yet almost superhuman in her radiant beauty. soon she stopped crying and smiled up at me bravely. "next morning i left. lylda took me through the tunnels and back into the forest by the river's edge where i had first met her. there we parted. i can see, now, her pathetic, drooping little figure as she trudged back to the tunnel. "when she had disappeared, i sat down to plan out my journey. i resolved now to reverse as nearly as possible the steps i had taken coming in. acting on this decision, i started back to that portion of the forest where i had trampled it down. "i found the place without difficulty, stopping once on the way to eat a few berries, and some of the food i carried with me. then i took a small amount of one of the drugs, and in a few moments the forest trees had dwindled into tiny twigs beneath my feet. "i started now to find the huge incline down which i had fallen, and when i reached it, after some hours of wandering, i followed its bottom edge to where a pile of rocks and dirt marked my former landing-place. the rocks were much larger than i remembered them, and so i knew i was not so large, now, as when i was here before. "remembering the amount of the drug i had taken coming down, i took now twelve of the pills. then, in a sudden panic, i hastily took two of the others. the result made my head swim most horribly. i sat or lay down, i forget which. when i looked up i saw the hills beyond the river and forest coming towards me, yet dwindling away beneath my feet as they approached. the incline seemed folding up upon itself, like a telescope. as i watched, its upper edge came into view, a curved, luminous line against the blackness above. every instant it crawled down closer, more sharply curved, and its inclined surface grew steeper. "all this time, as i stood still, the ground beneath my feet seemed to be moving. it was crawling towards me, and folding up underneath where i was standing. frequently i had to move to avoid rocks that came at me and passed under my feet into nothingness. "then, all at once, i realized that i had been stepping constantly backward, to avoid the inclined wall as it shoved itself towards me. i turned to see what was behind, and horror made my flesh creep at what i saw. a black, forbidding wall, much like the incline in front, entirely encircled me. it was hardly more than half a mile away, and towered four or five thousand feet overhead. "and as i stared in terror, i could see it closing in, the line of its upper edge coming steadily closer and lower. i looked wildly around with an overpowering impulse to run. in every direction towered this rocky wall, inexorably swaying in to crush me. "i think i fainted. when i came to myself the scene had not greatly changed. i was lying at the bottom and against one wall of a circular pit, now about a thousand feet in diameter and nearly twice as deep. the wall all around i could see was almost perpendicular, and it seemed impossible to ascend its smooth, shining sides. the action of the drug had evidently worn off, for everything was quite still. "my fear had now left me, for i remembered this circular pit quite well. i walked over to its center, and looking around and up to its top i estimated distances carefully. then i took two more of the pills. "immediately the familiar, sickening, crawling sensation began again. as the walls closed in upon me, i kept carefully in the center of the pit. steadily they crept in. now only a few hundred feet away! now only a few paces--and then i reached out and touched both sides at once with my hands. "i tell you, gentlemen, it was a terrifying sensation to stand in that well (as it now seemed), and feel its walls closing up with irresistible force. but now the upper edge was within reach of my fingers. i leaped upward and hung for a moment, then pulled myself up and scrabbled out, tumbling in a heap on the ground above. as i recovered myself, i looked again at the hole out of which i had escaped; it was hardly big enough to contain my fist. "i knew, now, i was at the bottom of the scratch. but how different it looked than before. it seemed this time a long, narrow cañon, hardly more than sixty feet across. i glanced up and saw the blue sky overhead, flooded with light, that i knew was the space of this room above the ring. "the problem now was quite a different one than getting out of the pit, for i saw that the scratch was so deep in proportion to its width that if i let myself get too big, i would be crushed by its walls before i could jump out. it would be necessary, therefore, to stay comparatively small and climb up its side. "i selected what appeared to be an especially rough section, and took a portion of another of the pills. then i started to climb. after an hour the buskins on my feet were torn to fragments, and i was bruised and battered as you saw me. i see, now, how i could have made both the descent into the ring, and my journey back with comparatively little effort, but i did the best i knew at the time. "when the cañon was about ten feet in width, and i had been climbing arduously for several hours, i found myself hardly more than fifteen or twenty feet above its bottom. and i was still almost that far from the top. with the stature i had then attained, i could have climbed the remaining distance easily, but for the fact that the wall above had grown too smooth to afford a foothold. the effects of the drug had again worn off, and i sat down and prepared to take another dose. i did so--the smallest amount i could--and held ready in my hand a pill of the other kind in case of emergency. steadily the walls closed in. "a terrible feeling of dizziness now came over me. i clutched the rock beside which i was sitting, and it seemed to melt like ice beneath my grasp. then i remembered seeing the edge of the cañon within reach above my head, and with my last remaining strength, i pulled myself up, and fell upon the surface of the ring. you know the rest. i took another dose of the powder, and in a few minutes was back among you." the chemist stopped speaking, and looked at his friends. "well," he said, "you've heard it all. what do you think of it?" "it is a terrible thing to me," sighed the very young man, "that you did not bring llyda with you." "it would have been a terrible thing if i had brought her. but i am going back for her." "when do you plan to go back?" asked the doctor after a moment. "as soon as i can--in a day or two," answered the chemist. "before you do your work here? you must not," remonstrated the big business man. "our war here needs you, our nation, the whole cause of liberty and freedom needs you. you cannot go." "lylda needs me, too," returned the chemist. "i have an obligation towards her now, you know, quite apart from my own feelings. understand me, gentlemen," he continued earnestly, "i do not place myself and mine before the great fight for democracy and justice being waged in this world. that would be absurd. but it is not quite that way, actually; i can go back for lylda and return here in a week. that week will make little difference to the war. on the other hand, if i go to france first, it may take me a good many months to complete my task, and during that time lylda will be using up her life several times faster than i. no, gentlemen, i am going to her first." "that week you propose to take," said the banker slowly, "will cost this world thousands of lives that you could save. have you thought of that?" the chemist flushed. "i can recognize the salvation of a nation or a cause," he returned hotly, "but if i must choose between the lives of a thousand men who are not dependent on me, and the life or welfare of one woman who is, i shall choose the woman." "he's right, you know," said the doctor, and the very young man agreed with him fervently. two days later the company met again in the privacy of the clubroom. when they had finished dinner, the chemist began in his usual quiet way: "i am going to ask you this time, gentlemen, to give me a full week. there are four of you--six hours a day of watching for each. it need not be too great a hardship. you see," he continued, as they nodded in agreement, "i want to spend a longer period in the ring world this time. i may never go back, and i want to learn, in the interest of science, as much about it as i can. i was there such a short time before, and it was all so strange and remarkable, i confess i learned practically nothing. "i told you all i could of its history. but of its arts, its science, and all its sociological and economic questions, i got hardly more than a glimpse. it is a world and a people far less advanced than ours, yet with something we have not, and probably never will have--the universally distributed milk of human kindness. yes, gentlemen, it is a world well worth studying." the banker came out of a brown study. "how about your formulas for these drugs?" he asked abruptly; "where are they?" the chemist tapped his forehead smilingly. "well, hadn't you better leave them with us?" the banker pursued. "the hazards of your trip--you can't tell----" "don't misunderstand me, gentlemen," broke in the chemist. "i wouldn't give you those formulas if my life and even lylda's depended on it. there again you do not differentiate between the individual and the race. i know you four very well. you are my friends, with all the bond that friendship implies. i believe in your integrity--each of you i trust implicitly. with these formulas you could crush germany, or you could, any one of you, rule the world, with all its treasures for your own. these drugs are the most powerful thing for good in the world to-day. but they are equally as powerful for evil. i would stake my life on what you would do, but i will not stake the life of a nation." "i know what i'd do if i had the formulas," began the very young man. "yes, but i don't know what you'd do," laughed the chemist. "don't you see i'm right?" they admitted they did, though the banker acquiesced very grudgingly. "the time of my departure is at hand. is there anything else, gentlemen, before i leave you?" asked the chemist, beginning to disrobe. "please tell lylda i want very much to meet her," said the very young man earnestly, and they all laughed. when the room was cleared, and the handkerchief and ring in place once more, the chemist turned to them again. "good-by, my friends," he said, holding out his hands. "one week from to-night, at most." then he took the pills. no unusual incident marked his departure. the last they saw of him he was calmly sitting on the ring near the scratch. then passed the slow days of watching, each taking his turn for the allotted six hours. by the fifth day, they began to hourly expect the chemist, but it passed through its weary length, and he did not come. the sixth day dragged by, and then came the last--the day he had promised would end their watching. still he did not come, and in the evening they gathered, and all four watched together, each unwilling to miss the return of the adventurer and his woman from another world. but the minutes lengthened into hours, and midnight found the white-faced little group, hopeful yet hopeless, with fear tugging at their hearts. a second week passed, and still they watched, explaining with an optimism they could none of them feel, the non-appearance of their friend. at the end of the second week they met again to talk the situation over, a dull feeling of fear and horror possessing them. the doctor was the first to voice what now each of them was forced to believe. "i guess it's all useless," he said. "he's not coming back." "i don't hardly dare give him up," said the big business man. "me, too," agreed the very young man sadly. the doctor sat for some time in silence, thoughtfully regarding the ring. "my friends," he began finally, "this is too big a thing to deal with in any but the most careful way. i can't imagine what is going on inside that ring, but i do know what is happening in our world, and what our friend's return means to civilization here. under the circumstances, therefore, i cannot, i will not give him up. "i am going to put that ring in a museum and pay for having it watched indefinitely. will you join me?" he turned to the big business man as he spoke. "make it a threesome," said the banker gruffly. "what do you take me for?" and the very young man sighed with the tragedy of youth. chapter ix after five years four men sat in the clubroom, at their ease in the luxurious leather chairs, smoking and talking earnestly. near the center of the room stood a huge mahogany table. on its top, directly in the glare of light from an electrolier overhead, was spread a large black silk handkerchief. in the center of this handkerchief lay a heavy gold band--a woman's wedding-ring. an old-fashioned valise stood near a corner of the table. its sides were perforated with small brass-rimmed holes; near the top on one side was a small square aperture covered with a wire mesh through which one might look into the interior. altogether, from the outside, the bag looked much like those used for carrying small animals. as it lay on the table now its top was partly open. the inside was brightly lighted by a small storage battery and electric globe, fastened to the side. near the bottom of the bag was a tiny wire rack, held suspended about an inch from the bottom by transverse wires to the sides. the inside of the bag was lined with black plush. on an arm of the doctor's chair lay two white tin boxes three or four inches square. in his hand he held an opened envelope and several letter pages. "a little more than five years ago to-night, my friends," he began slowly, "we sat in this room with that"--he indicated the ring--"under very different circumstances." after a moment, he went on: "i think i am right when i say that for five years the thought uppermost in our minds has always been that ring and what is going on within one of its atoms." "you bet," said the very young man. "for five years now we have had the ring watched," continued the doctor, "but rogers has never returned." "you asked us here to-night because you had something special to tell us," began the very young man, with a questioning look at the valise and the ring. the doctor smiled. "i'm sorry," he said, "i don't mean to be aggravating." "go ahead in your own way, frank," the big business man put in. "we'll wait if we have to." the doctor glanced at the papers in his hand; he had just taken them from the envelope. "you are consumed with curiosity, naturally, to know what i have to say--why i have brought the ring here to-night. gentlemen, you have had to restrain that curiosity less than five minutes; i have had a far greater curiosity to endure--and restrain--for over five years. "when rogers left us on his last journey into the ring, he gave into my keeping, unknown to you, this envelope." the doctor held it up. "he made me swear i would keep its existence secret from every living being, until the date marked upon it, at which time, in the event of his not having returned, it was to be opened. look at it." the doctor laid the envelope on the table. "it is inscribed, as you see, 'to be opened by dr. frank adams at p. m. on september th, .' for five years, gentlemen, i kept that envelope, knowing nothing of its contents and waiting for the moment when i might, with honor, open it. the struggle has been a hard one. many times i have almost been able to persuade myself, in justice to our friend's safety--his very life, probably--that it would be best to disregard his instructions. but i did not; i waited until the date set and then, a little more than a month ago, alone in my office, i opened the envelope." the doctor leaned forward in his chair and shuffled the papers he held in his hand. his three friends sat tense, waiting. "the envelope contained these papers. among them is a letter in which i am directed to explain everything to you as soon as i succeed in doing certain other things. those things i have now accomplished. so i have sent for you. i'll read you the letter first." no one spoke when the doctor paused. the banker drew a long breath. then he bit the end off a fresh cigar and lit it with a shaking hand. the doctor shifted his chair closer to the table under the light. "the letter is dated september th, . it begins: 'this will be read at p. m. on september th, , by dr. frank adams with no one else present. if the envelope has been opened by him previous to that date i request him to read no further. if it has fallen into other hands than his i can only hope that the reader will immediately destroy it unread.'" the doctor paused an instant, then went on. "gentlemen, we are approaching the most important events of our lives. an extraordinary duty--a tremendous responsibility, rests with us, of all the millions of people on this earth. i ask that you listen most carefully." his admonition was quite unnecessary, for no one could have been more intent than the three men silently facing him. the doctor continued reading: "'from dr. frank adams, i exact the following oath, before he reads further. you, dr. adams, will divulge to no one, for a period of thirty days, the formulas set down in these papers; you will follow implicitly the directions given you; you will do nothing that is not expressly stated here. should you be unable to carry out these directions, you will destroy this letter and the formulas, and tell no one of their ever having been in existence. i must have your oath, dr. adams, before you proceed further.'" the doctor's voice died away, and he laid the papers on the table. "gentlemen," he went on, "later on in the letter i am directed to consult with you three, setting before you this whole matter. but before i do so i must exact a similar oath from each of you. i must have your word of honor, gentlemen, that you will not attempt to transgress the instructions given us, and that you will never, by word or action, allow a suggestion of what passes between us here in this room to-night, to reach any other person. have i your promise?" each of his three hearers found voice to agree. the banker's face was very red, and he mopped his forehead nervously with his handkerchief. the doctor picked up the papers. "the letter goes on: 'i am about to venture back into the unknown world of the ring. what will befall me there i cannot foretell. if by september th, , i have not returned, or no other mortal has come out of the ring, it is my desire that you and the three gentlemen with you at the time of my departure, use this discovery of mine for the benefit of humanity in your world, or the world in the ring, exactly as i myself would have used it were i there. "'should the european war be in progress at that time, i direct that you four throw your power on the side of the united states for the defeat of the central powers. that you will be able to accomplish that defeat i cannot doubt. "'if, on september th, , the united states is formally at peace with the powers of the world, you are forbidden to use these chemicals for any purpose other than joining me in the world of the ring. if any among you wish to make the venture, which i hope may be the case, i request that you do so. "'among these pages you will find a list of fourteen chemicals to be used by dr. frank adams during the month following september , , for the compounding of my powders. seven of these chemicals (marked a), are employed in the drug used to diminish bodily size. those seven marked b are for the drug of opposite action. "'you will find here a separate description of each chemical. nine are well known and fairly common. dr. adams will be able to purchase each of them separately without difficulty. three others will have to be especially compounded and i have so stated in the directions for each of them. dr. adams can have them prepared by any large chemical manufacturer; i suggest that he have not more than one of them compounded by the same company. "'the two remaining chemicals must be prepared by dr. adams personally. their preparation, while intricate, demands no complicated or extensive apparatus. i have tried to explain thoroughly the making of these two chemicals, and i believe no insurmountable obstacle will be met in completing them. "'when dr. adams has the specified quantities of each of these fourteen chemicals in his possession, he will proceed according to my further directions to compound the two drugs. if he is successful in making these drugs, i direct that he make known to the three other men referred to, the contents of this letter, after first exacting an oath from each that its provisions will be carried out. "'i think it probable that dr. adams will succeed in compounding these two drugs. it also seems probable that at that time the united states no longer will be at war. i make the additional assumption that one or more of you gentlemen will desire to join me in the ring. therefore, you will find herewith memoranda of my first journey into the ring which i have already described to you; i give also the quantities of each drug to be taken at various stages of the trip. these notes will refresh your memory and will assist you in your journey. "'i intend to suggest to dr. adams to-day when i hand him this letter, that in the event of my failure to return within a week, he make some adequate provision for guarding the ring in safety. and i must caution you now, before starting to join me, if you conclude to do so, that you continue this provision, so as to make possible your safe return to your own world. "'if our country is at war at the time you read this, your duty is plain. i have no fears regarding your course of action. but if not, i do not care to influence unduly your decision about venturing into this unknown other world. the danger into which i personally may have fallen must count for little with you, in a decision to hazard your own lives. i may point out, however, that such a journey successfully accomplished cannot fail but be the greatest contribution to science that has ever been made. nor can i doubt but that your coming may prove of tremendous benefit to the humanity of this other equally important, though, in our eyes, infinitesimal world. "'i therefore suggest, gentlemen, that you start your journey into the ring at p. m. on the evening of november , . you will do your best to find your way direct to the city of arite, where, if i am alive, i will be awaiting you.'" chapter x testing the drugs the doctor laid his papers on the table and looked up into the white faces of the three men facing him. "that's all, gentlemen," he said. for a moment no one spoke, and on the face of each was plainly written the evidence of an emotion too deep for words. the doctor sorted out the papers in silence, glanced over them for a moment, and then reached for a large metal ash tray that stood near him on the table. taking a match from his pocket he calmly lighted a corner of the papers and dropped them burning into the metal bowl. his friends watched him in awed silence; only the very young man found words to protest. "say now, wait," he began, "why----" the doctor looked at him. "the letter requests me to do that," he said. "but i say, the formulas----" persisted the very young man, looking wildly at the burning papers. the doctor held up one of the white tin boxes lying on the arm of his chair. "in these tins," he said, "i have vials containing the specified quantity of each drug. it is ample for our purpose. i have done my best to memorize the formulas. but in any event, i was directed to burn them at the time of reading you the letter. i have done so." the big business man came out of a brown study. "just three weeks from to-night," he murmured, "three weeks from to-night. it's too big to realize." the doctor put the two boxes on the table, turned his chair back toward the others, and lighted a cigar. "gentlemen, let us go over this matter thoroughly," he began. "we have a momentous decision to make. either we destroy those boxes and their contents, or three weeks from to-night some or all of us start our journey into the ring. i have had a month to think this matter over; i have made my decision. "i know there is much for you to consider, before you can each of you choose your course of action. it is not my desire or intention to influence you one way or the other. but we can, if you wish, discuss the matter here to-night; or we can wait, if you prefer, until each of you has had time to think it out for himself." "i'm going," the very young man burst out. his hands were gripping the arms of his chair tightly; his face was very pale, but his eyes sparkled. the doctor turned to him gravely. "your life is at stake, my boy," he said, "this is not a matter for impulse." "i'm going whether any one else does or not," persisted the very young man. "you can't stop me, either," he added doggedly. "that letter said----" the doctor smiled at the youth's earnestness. then abruptly he held out his hand. "there is no use my holding back my own decision. i am going to attempt the trip. and since, as you say, i cannot stop you from going," he added with a twinkle, "that makes two of us." they shook hands. the very young man lighted a cigarette, and began pacing up and down the room, staring hard at the floor. "i can remember trying to imagine how i would feel," began the big business man slowly, "if rogers had asked me to go with him when he first went into the ring. it is not a new idea to me, for i have thought about it many times in the abstract, during the past five years. but now that i am face to face with it in reality, it sort of----" he broke off, and smiled helplessly around at his companions. the very young man stopped in his walk. "aw, come on in," he began, "the----" "shut up," growled the banker, speaking for the first time in many minutes. "i'm sure we would all like to go," said the doctor. "the point is, which of us are best fitted for the trip." "none of us are married," put in the very young man. "i've been thinking----" began the banker. "suppose we get into the ring--how long would we be gone, do you suppose?" "who can say?" answered the doctor smiling. "perhaps a month--a year--many years possibly. that is one of the hazards of the venture." the banker went on thoughtfully. "do you remember that argument we had with rogers about time? time goes twice as fast, didn't he say, in that other world?" "two and a half times faster, if i remember rightly, he estimated," replied the doctor. the banker looked at his skinny hands a moment. "i owned up to sixty-four once," he said quizzically. "two years and a half in one year. no, i guess i'll let you young fellows tackle that; i'll stay here in this world where things don't move so fast." "somebody's got to stay," said the very young man. "by golly, you know if we're all going into that ring it would be pretty sad to have anything happen to it while we were gone." "that's so," said the banker, looking relieved. "i never thought of that." "one of us should stay at least," said the doctor. "we cannot take any outsider into our confidence. one of us must watch the others go, and then take the ring back to its place in the museum. we will be gone too long a time for one person to watch it here." the very young man suddenly went to one of the doors and locked it. "we don't want any one coming in," he explained as he crossed the room and locked the others. "and another thing," he went on, coming back to the table. "when i saw the ring at the biological society the other day, i happened to think, suppose rogers was to come out on the underneath side? it was lying flat, you know, just as it is now." he pointed to where the ring lay on the handkerchief before them. "i meant to speak to you about it," he added. "i thought of that," said the doctor. "when i had that case built to bring the ring here, you notice i raised it above the bottom a little, holding it suspended in that wire frame." "we'd better fix up something like that at the museum, too," said the very young man, and went back to his walk. the big business man had been busily jotting down figures on the back of an envelope. "i can be in shape to go in three weeks," he said suddenly. "bully for you," said the very young man. "then it's all settled." the big business man went back to his notes. "i knew what your answer would be," said the doctor. "my patients can go to the devil. this is too big a thing." the very young man picked up one of the tin boxes. "tell us how you made the powders," he suggested. the doctor took the two boxes and opened them. inside each were a number of tiny glass vials. those in one box were of blue glass; those in the other were red. "these vials," said the doctor, "contain tiny pellets of the completed drug. that for diminishing size i have put in the red vials; those of blue are the other drug. "i had rather a difficult time making them--that is, compared to what i anticipated. most of the chemicals i bought without difficulty. but when i came to compound those two myself"--the doctor smiled--"i used to think i was a fair chemist in my student days. but now--well, at least i got the results, but only because i have been working almost night and day for the past month. and i found myself with a remarkably complete experimental laboratory when i finished," he added. "that was yesterday; i spent nearly all last night destroying the apparatus, as soon as i found that the drugs had been properly made." "they do work?" said the very young man anxiously. "they work," answered the doctor. "i tried them both very carefully." "on yourself?" said the big business man. "no, i didn't think that necessary. i used several insects." "let's try them now," suggested the very young man eagerly. "not the big one," said the banker. "once was enough for that." "all right," the doctor laughed. "we'll try the other if you like." the big business man looked around the room. "there's a few flies around here if we can catch one," he suggested. "i'll bet there's a cockroach in the kitchen," said the very young man, jumping up. the doctor took a brass check from his pocket. "i thought probably you'd want to try them out. will you get that box from the check-room?" he handed the check to the very young man, who hurried out of the room. he returned in a moment, gingerly carrying a cardboard box with holes perforated in the top. the doctor took the box and lifted the lid carefully. inside, the box was partitioned into two compartments. in one compartment were three little lizards about four inches long; in the other were two brown sparrows. the doctor took out one of the sparrows and replaced the cover. "fine," said the very young man with enthusiasm. the doctor reached for the boxes of chemicals. "not the big one," said the banker again, apprehensively. "hold him, will you," the doctor said. the very young man took the sparrow in his hands. "now," continued the doctor, "what we need is a plate and a little water." "there's a tray," said the very young man, pointing with his hands holding the sparrow. the doctor took a spoon from the tray and put a little water in it. then he took one of the tiny pellets from a red vial and crushing it in his fingers, sprinkled a few grains into that water. "hold that a moment, please." the big business man took the proffered spoon. then the doctor produced from his pocket a magnifying glass and a tiny pair of silver callipers such as are used by jewelers for handling small objects. "what's the idea?" the very young man wanted to know. "i thought i'd try and put him on the ring," explained the doctor. "now, then hold open his beak." the very young man did so, and the doctor poured the water down the bird's throat. most of it spilled; the sparrow twisted its head violently, but evidently some of the liquid had gone down the bird's throat. silence followed, broken after a moment by the scared voice of the very young man. "he's getting smaller, i can feel him. he's getting smaller." "hold on to him," cautioned the doctor. "bring him over here." they went over to the table by the ring, the banker and the big business man standing close beside them. "suppose he tries to fly when we let go of him," suggested the very young man almost in a whisper. "he'll probably be too confused," answered the doctor. "have you got him?" the sparrow was hardly bigger than a large horse-fly now, and the very young man was holding it between his thumb and forefinger. "better give him to me," said the doctor. "set him down." "he might fly away," remonstrated the very young man. "no, he won't." the very young man put the sparrow on the handkerchief beside the ring and the doctor immediately picked it up with the callipers. "don't squeeze him," cautioned the very young man. the sparrow grew steadily smaller, and in a moment the doctor set it carefully on the rim of the ring. "get him up by the scratch," whispered the very young man. the men bent closer over the table, as the doctor looking through his magnifying glass shoved the sparrow slowly along the top of the ring. "i can't see him," said the banker. "i can," said the very young man, "right by the scratch." then after a moment, "he's gone." "i've got him right over the scratch," said the doctor, leaning farther down. then he raised his head and laid the magnifying glass and the callipers on the table. "he's gone now." "gosh," said the very young man, drawing a long breath. the banker flung himself into a chair as though exhausted from a great physical effort. "well, it certainly does work," said the big business man, "there's no question about that." the very young man was shaking the cardboard box in his hands and lifting its cover cautiously to see inside. "let's try a lizard," he suggested. "oh, what's the use," the banker protested wearily, "we know it works." "well, it can't hurt anything to try it, can it?" the very young man urged. "besides, the more we try it, the more sure we are it will work with us when the time comes. you don't want to try it on yourself, now, do you?" he added with a grin. "no, thank you," retorted the banker with emphasis. "i think we might as well try it again," said the big business man. the very young man took one of the tiny lizards from the box, and in a moment they had dropped some water containing the drug down its throat. "try to put him on the scratch, too," said the very young man. when the lizard was small enough the doctor held it with the callipers and then laid it on the ring. "look at him walk; look at him walk," whispered the very young man excitedly. the lizard, hardly more than an eighth of an inch long now, but still plainly visible, was wriggling along the top of the ring. "shove him up by the scratch," he added. in a moment more the reptile was too small for any but the doctor with his glass to see. "i guess he got there," he said finally with a smile, as he straightened up. "he was going fast." "well, _that's_ all right," said the very young man with a sigh of relief. the four men again seated themselves; the big business man went back to his figures. "when do you start?" asked the banker after a moment. "november th-- p. m.," answered the doctor. "three weeks from to-night." "we've a lot to do," said the banker. "what will this cost, do you figure?" asked the big business man, looking up from his notes. the doctor considered a moment. "we can't take much with us, you know," he said slowly. then he took a sheet of memoranda from his pockets. "i have already spent for apparatus and chemicals to prepare the drugs"--he consulted his figures--"seventeen hundred and forty dollars, total. what we have still to spend will be very little, i should think. i propose we divide it three ways as we have been doing with the museum?" "four ways," said the very young man. "i'm no kid any more. i got a good job--that is," he added with a rueful air, "i had a good job. to-morrow i quit." "four ways," the doctor corrected himself gravely. "i guess we can manage that." "what can we take with us, do you think?" asked the big business man. "i think we should try strapping a belt around our waists, with pouches in it," said the doctor. "i doubt if it would contract with our bodies, but still it might. if it didn't there would be no harm done; we could leave it behind." "you want food and water," said the banker. "remember that barren country you are going through." "and something on our feet," the big business man put in. "i'd like to take a revolver, too," said the very young man. "it might come in awful handy." "as i remember rogers's description," said the doctor thoughtfully, "the trip out is more difficult than going down. we mustn't overlook preparations for that; it is most imperative we should be careful." "say, talking about getting back," burst out the very young man. "i'd like to see that other drug work first. it would be pretty rotten to get in there and have it go back on us, wouldn't it? oh, golly!" the very young man sank back in his chair overcome by the picture he had conjured up. "i tried it," said the doctor. "it works." "i'd like to see it again with something different," said the big business man. "it can't do any harm." the banker looked his protest, but said nothing. "what shall we try, a lizard?" suggested the very young man. the doctor shrugged his shoulders. "what'll we kill it with? oh, i know." the very young man picked up a heavy metal paper-weight from the desk. "this'll do the trick, fine," he added. then, laying the paper-weight carefully aside, he dipped up a spoonful of water and offered it to the doctor. "not that water this time," said the doctor, shaking his head with a smile. the very young man looked blank. "organisms in it," the doctor explained briefly. "all right for them to get small from the other chemical, but we don't want them to get large and come out at us, do we?" "holy smoke, i should say not," said the very young man, gasping; and the banker growled: "something's going to happen to us, playing with fire like this." the doctor produced a little bottle. "i boiled this water," he said. "we can use this." it took but a moment to give the other drug to one of the remaining lizards, although they spilled more of the water than went down its throat. "don't forget to hit him, and don't you wait very long," said the banker warningly, moving nearer the door. "oh, i'll hit him all right, don't worry," said the very young man, brandishing the paper-weight. the doctor knelt down, and held the reptile pinned to the floor; the very young man knelt beside him. slowly the lizard began to increase in size. "he's growing," said the banker. "hit him, boy, what's the use of waiting; he's growing." the lizard was nearly a foot long now, and struggling violently between the doctor's fingers. "you'd better kill him," said the doctor, "he might get away from me." the very young man obediently brought his weapon down with a thump upon the reptile's head. "keep on," said the banker. "be sure he's dead." the very young man pounded the quivering body for a moment. the big business man handed him a napkin from the tray and the very young man wrapped up the lizard and threw it into the waste-basket. then he rose to his feet and tossed the paper-weight on to the desk with a crash. "well, gentlemen," he said, turning back to them with flushed face, "those drugs sure do work. we're going into the ring all right, three weeks from to-night, and nothing on earth can stop us." chapter xi the escape of the drug for the next hour the four friends busily planned their preparations for the journey. when they began to discuss the details of the trip, and found themselves face to face with so hazardous an adventure, each discovered a hundred things in his private life that needed attention. the doctor's phrase, "my patients can go to the devil," seemed to relieve his mind of all further responsibility towards his personal affairs. "that's all very well for you," said the big business man, "i've too many irons in the fire just to drop everything--there are too many other people concerned. and i've got to plan as though i were never coming back, you know." "your troubles are easy," said the very young man. "i've got a girl. i wonder what she'll say. oh, gosh, i can't tell her where i'm going, can i? i never thought of that." he scratched his head with a perplexed air. "that's tough on her. well, i'm glad i'm an orphan, anyway." the actual necessities of the trip needed a little discussion, for what they could take with them amounted to practically nothing. "as i understand it," said the banker, "all i have to do is watch you start, and then take the ring back to the museum." "take it carefully," continued the very young man. "remember what it's got in it." "you will give us about two hours to get well started down," said the doctor. "after that it will be quite safe to move the ring. you can take it back to the society in that case i brought it here in." "be sure you take it yourself," put in the very young man. "don't trust it to anybody else. and how about having that wire rack fixed for it at the museum," he added. "don't forget that." "i'll have that done myself this week," said the doctor. they had been talking for perhaps an hour when the banker got up from his chair to get a fresh cigar from a box that lay upon the desk. he happened to glance across the room and on the floor in the corner by the closed door he saw a long, flat object that had not been there before. it was out of the circle of light and being brown against the polished hardwood floor, he could not make it out clearly. but something about it frightened him. "what's that over there?" he asked, standing still and pointing. the big business man rose from his seat and took a few steps in the direction of the banker's outstretched hand. then with a muttered oath he jumped to the desk in a panic and picking up the heavy paper-weight flung it violently across the room. it struck the panelled wall with a crash and bounded back towards him. at the same instant there came a scuttling sound from the floor, and a brown shape slid down the edge of the room and stopped in the other corner. all four men were on their feet in an instant, white-faced and trembling. "good god," said the big business man huskily, "that thing over there--that----" "turn on the side lights--the side lights!" shouted the doctor, running across the room. in the glare of the unshaded globes on the wall the room was brightly lighted. on the floor in the corner the horrified men saw a cockroach nearly eighteen inches in length, with its head facing the angle of wall, and scratching with its legs against the base board as though about to climb up. for a moment the men stood silent with surprise and terror. then, as they stared they saw the cockroach was getting larger. the big business man laid his hand on the doctor's arm with a grip that made the doctor wince. "good god, man, look at it--it's growing," he said in a voice hardly above a whisper. "it's growing," echoed the very young man; "_it's growing_!" and then the truth dawned upon them, and brought with it confusion, almost panic. the cockroach, fully two feet long now, had raised the front end of its body a foot above the floor, and was reaching up the wall with its legs. the banker made a dash for the opposite door. "let's get out of here. come on!" he shouted. the doctor stopped him. of the four men, he was the only one who had retained his self-possession. "listen to me," he said. his voice trembled a little in spite of his efforts to control it. "listen to me. that--that--thing cannot harm us yet." he looked from one to the other of them and spoke swiftly. "it's gruesome and--and loathsome, but it is not dangerous--yet. but we cannot run from it. we must kill it--here, now, before it gets any larger." the banker tore himself loose and started again towards the door. "you fool!" said the doctor, with a withering look. "don't you see, it's life or death later. that--that thing will be as big as this house in half an hour. don't you know that? as big as this house. we've got to kill it now--now." the big business man ran towards the paper-weight. "i'll hit it with this," he said. "you can't," said the doctor, "you might miss. we haven't time. look at it," he added. the cockroach was noticeably larger now--considerably over two feet; it had turned away from the wall to face them. the very young man had said nothing; only stood and stared with bloodless face and wide-open eyes. then suddenly he stooped, and picking up a small rug from the floor--a rug some six feet long and half as wide--advanced slowly towards the cockroach. "that's the idea," encouraged the doctor. "get it under that. here, give me part of it." he grasped a corner of the rug. "you two go up the other sides"--he pointed with his free hand--"and head it off if it runs." slowly the four men crept forward. the cockroach, three feet long now, was a hideous, horrible object as it stood backed into the corner of the room, the front part of its body swaying slowly from side to side. "we'd better make a dash for it," whispered the very young man; and jerking the rug loose from the doctor's grasp, he leaped forward and flung himself headlong upon the floor, with the rug completely under him. "i've got the damned thing. i've got it!" he shouted. "help--you. help!" the three men leaped with him upon the rug, holding it pinned to the floor. the very young man, as he lay, could feel the curve of the great body underneath, and could hear the scratch of its many legs upon the floor. "hold down the edges of the rug!" he cried. "don't let it out. don't let it get out. i'll smash it." he raised himself on his hands and knees, and came down heavily. the rug gave under his thrust as the insect flattened out; then they could hear again the muffled scratching of its legs upon the floor as it raised the rug up under the very young man's weight. "we can't kill it," panted the big business man. "oh, we can't kill it. good god, how big it is!" the very young man got to his feet and stood on the bulge of the rug. then he jumped into the air and landed solidly on his heels. there was a sharp crack as the shell of the insect broke under the sharpness of his blow. "that did it; that'll do it!" he shouted. then he leaped again. "let me," said the big business man. "i'm heavier"; and he, too, stamped upon the rug with his heels. they could hear the huge shell of the insect's back smash under his weight, and when he jumped again, the squash of its body as he mashed it down. "wait," said the doctor. "we've killed it." they eased upon the rug a little, but there was no movement from beneath. "jump on it harder," said the very young man. "don't let's take a chance. mash it good." the big business man continued stamping violently upon the rug; joined now by the very young man. the doctor sat on the floor beside it, breathing heavily; the banker lay in a heap at its foot in utter collapse. as they stamped, the rug continued to flatten down; it sank under their tread with a horrible, sickening, squashing sound. "let's look," suggested the very young man. "it must be dead"; and he threw back a corner of the rug. the men turned sick and faint at what they saw. underneath the rug, mashed against the floor, lay a great, noisome, semi-liquid mass of brown and white. it covered nearly the entire under-surface of the rug--a hundred pounds, perhaps, of loathsome pulp and shell, from which a stench arose that stopped their breathing. with a muttered imprecation the doctor flung back the rug to cover it, and sprang to his feet, steadying himself against a chair. "we killed it in time, thank god," he murmured and dropped into the chair, burying his face in his hands. for a time silence fell upon the room, broken only by the labored breathing of the four men. then the big business man sat up suddenly. "oh, my god, what an experience!" he groaned, and got unsteadily to his feet. the very young man helped the banker up and led him to a seat by the window, which he opened, letting in the fresh, cool air of the night. "how did the drug get loose, do you suppose?" asked the very young man, coming back to the center of the room. he had recovered his composure somewhat, though he was still very pale. he lighted a cigarette and sat down beside the doctor. the doctor raised his head wearily. "i suppose we must have spilled some of it on the floor," he said, "and the cockroach----" he stopped abruptly and sprang to his feet. "good god!" he cried. "suppose another one----" on the bare floor beside the table they came upon a few drops of water. "that must be it," said the doctor. he pulled his handkerchief from his pocket; then he stopped in thought. "no, that won't do. what shall we do with it?" he added. "we must destroy it absolutely. good lord, if that drug ever gets loose upon the world----" the big business man joined them. "we must destroy it absolutely," repeated the doctor. "we can't just wipe it up." "some acid," suggested the big business man. "suppose something else has got at it already," the very young man said in a scared voice, and began hastily looking around the floor of the room. "you're right," agreed the doctor. "we mustn't take any chance; we must look thoroughly." joined by the banker, the four men began carefully going over the room. "you'd better watch that nothing gets at it," the very young man thought suddenly to say. the banker obediently sat down by the little pool of water on the floor. "and i'll close the window," added the very young man; "something might get out." they searched the room thoroughly, carefully scanning its walls and ceiling, but could see nothing out of the ordinary. "we'll never be quite sure," said the doctor finally, "but i guess we're safe. it's the best we can do now, at any rate." he joined the banker by the table. "i'll get some nitric acid," he added. "i don't know what else----" "we'll have to get that out of here, too," said the big business man, pointing to the rug. "god knows how we'll explain it." the doctor picked up one of the tin boxes of drugs and held it in his hand meditatively. then he looked over towards the rug. from under one side a brownish liquid was oozing; the doctor shuddered. "my friends," he said, holding up the box before them, "we can realize now something of the terrible power we have created and imprisoned here. we must guard it carefully, gentlemen, for if it escapes--it will destroy the world." chapter xii the start on the evening of november th, , the four friends again assembled at the scientific club for the start of their momentous adventure. the doctor was the last to arrive, and found the other three anxiously awaiting him. he brought with him the valise containing the ring and a suitcase with the drugs and equipment necessary for the journey. he greeted his friends gravely. "the time has come, gentlemen," he said, putting the suitcase on the table. the big business man took out the ring and held it in his hand thoughtfully. "the scene of our new life," he said with emotion. "what does it hold in store for us?" "what time is it?" asked the very young man. "we've got to hurry. we want to get started on time--we mustn't be late." "everything's ready, isn't it?" asked the banker. "who has the belts?" "they're in my suitcase," answered the very young man. "there it is." the doctor laid the ring and handkerchief on the floor under the light and began unpacking from his bag the drugs and the few small articles they had decided to try and take with them. "you have the food and water," he said. the big business man produced three small flasks of water and six flat, square tins containing compressed food. the very young man opened one of them. "chocolate soldiers we are," he said, and laughed. the banker was visibly nervous and just a little frightened. "are you sure you haven't forgotten something?" he asked, quaveringly. "it wouldn't make a great deal of difference if we had," said the doctor, with a smile. "the belts may not contract with us at all; we may have to leave them behind." "rogers didn't take anything," put in the very young man. "come on; let's get undressed." the banker locked the doors and sat down to watch the men make their last preparations. they spoke little while they were disrobing; the solemnity of what they were about to do both awed and frightened them. only the very young man seemed exhilarated by the excitement of the coming adventure. in a few moments the three men were dressed in their white woolen bathing suits. the very young man was the first to be fully equipped. "i'm ready," he announced. "all but the chemicals. where are they?" around his waist he had strapped a broad cloth belt, with a number of pockets fastened to it. on his feet were felt-lined cloth shoes, with hard rubber soles; he wore a wrist watch. under each armpit was fastened the pouch for carrying the drugs. "left arm for red vials," said the doctor. "be sure of that--we mustn't get them mixed. take two of each color." he handed the very young man the tin boxes. all the men were ready in a moment more. "five minutes of eight," said the very young man, looking at his watch. "we're right on time; let's get started." the banker stood up among them. "tell me what i've got to do," he said helplessly. "you're going all but me; i'll be left behind alone." the big business man laid his hand on the banker's shoulder affectionately. "don't look so sad, george," he said, with an attempt at levity. "we're not leaving you forever--we're coming back." the banker pressed his friend's hand. his usual crusty manner was quite gone now; he seemed years older. the doctor produced the same spoon he had used when the chemist made his departure into the ring. "i've kept it all this time," he said, smiling. "perhaps it will bring us luck." he handed it to the banker. "what you have to do is this," he continued seriously. "we shall all take an equal amount of the drug at the same instant. i hope it will act upon each of us at the same rate, so that we may diminish uniformly in size, and thus keep together." "gosh!" said the very young man. "i never thought of that. suppose it doesn't?" "then we shall have to adjust the difference by taking other smaller amounts of the drug. but i think probably it will. "you must be ready," he went on to the banker, "to help us on to the ring if necessary." "or put us back if we fall off," said the very young man. "i'm going to sit still until i'm pretty small. gracious, it's going to feel funny." "after we have disappeared," continued the doctor, "you will wait, say, until eleven o'clock. watch the ring carefully--some of us may have to come back before that time. at eleven o'clock pack up everything"--he looked around the littered room with a smile--"and take the ring back to the biological society." "keep your eye on it on the way back," warned the very young man. "suppose we decide to come out some time later to-night--you can't tell." "i'll watch it all night to-night, here and at the museum," said the banker, mopping his forehead. "good scheme," said the very young man approvingly. "anything might happen." "well, gentlemen," said the doctor, "i believe we're all ready. come on, will." the big business man was standing by the window, looking out intently. he evidently did not hear the remark addressed to him, for he paid no attention. the doctor joined him. through the window they could see the street below, crowded now with scurrying automobiles. the sidewalks were thronged with people--theater-goers, hurrying forward, seeking eagerly their evening's pleasure. it had been raining, and the wet pavements shone with long, blurred yellow glints from the thousands of lights above. down the street they could see a huge blazing theater sign, with the name of a popular actress spelt in letters of fire. the big business man threw up the window sash and took a deep breath of the moist, cool air of the night. "good-by, old world," he murmured with emotion. "shall i see you again, i wonder?" he stood a moment longer, silently staring at the scene before him. then abruptly he closed the window, pulled down the shade, and turned back to the room. "come on," said the very young man impatiently. "it's five minutes after eight. let's get started." "just one thing before we start," said the doctor, as they gathered in the center of the room. "we must understand, gentlemen, from the moment we first take the drug, until we reach our final smallest size, it is imperative, or at least highly desirable, that we keep together. we start by taking four of the pellets each, according to the memoranda rogers left. by jove!" he interrupted himself, "that's one thing important we did nearly forget." he went to his coat, and from his wallet took several typewritten sheets of paper. "i made three copies," he said, handing them to his companions. "put them away carefully; the front pocket will be most convenient, probably. "it may not be hard for us to keep together," continued the doctor. "on the other hand, we may find it extremely difficult, if not quite impossible. in the latter event we will meet at the city of arite. "there are two things we must consider. first, we shall be constantly changing size with relation to our surroundings. in proportion to each other, we must remain normal in size if we can. secondly we shall be traveling--changing position in our surroundings. so far as that aspect of the trip is concerned, it will not be more difficult for us to keep together, probably, than during any adventurous journey here in this world. "if through accident or any unforeseen circumstance we are separated in size, the one being smallest shall wait for the others. that can be accomplished by taking a very small quantity of the other drug--probably merely by touching one of the pellets to the tongue. do i make myself clear?" his friends nodded assent. "if any great separation in relative size occurs," the doctor went on, "a discrepancy sufficient to make the smallest of us invisible for a time to the others, then another problem presents itself. we must be very careful, in that event, not to change our position in space--not to keep on traveling, in other words--or else, when we become the same size once more, we will be out of sight of one another. geographically separated, so to speak," the doctor finished with a smile. "i am so explicit on this point of keeping together," he continued, "because--well, i personally do not want to undertake even part of this journey alone." "you're darn right--me neither," agreed the very young man emphatically. "let's get going." "i guess that's all," said the doctor, with a last glance around, and finally facing the banker. "good-by, george." the banker was quite overcome, and without a word he shook hands with each of his friends. the three men sat beside each other on the floor, close to the handkerchief and ring; the banker sat in his chair on the other side, facing them, spoon in hand. in silence they each took four of the pellets. then the banker saw them close their eyes; he saw the big business man put his hands suddenly on the floor as though to steady himself. the banker gripped the arms of his chair firmly. he knew exactly what to expect, yet now when his friends began slowly to diminish in size he was filled with surprise and horror. for several minutes no one spoke. then the very young man opened his eyes, looked around dizzily for an instant, and began feeling with his hands the belt at his waist, his shoes, wrist-watch, and the pouches under his armpits. "it's all right," he said with an enthusiasm that contrasted strangely with the tremor in his voice. "the belt's getting smaller, too. we're going to be able to take everything with us." again silence fell on the room, broken only by the sound of the three men on the floor continually shifting their positions as they grew smaller. in another moment the doctor clambered unsteadily to his feet and, taking a step backward, leaned up against the cylindrical mahogany leg of the center-table, flinging his arms around it. his head did not reach the table-top. the very young man and the big business man were on their feet now, too, standing at the edge of the handkerchief, and clinging to one another for support. the banker looked down at them and tried to smile. the very young man waved his hand, and the banker found voice to say: "good-by, my boy." "good-by, sir," echoed the very young man. "we're making it." steadily they grew smaller. by this time the doctor had become far too small for his arms to encircle the leg of the table. the banker looked down to the floor, and saw him standing beside the table leg, leaning one hand against it as one would lean against the great stone column of some huge building. "good-by, frank," said the banker. but the doctor did not answer; he seemed lost in thought. several minutes more passed in silence. the three men had diminished in size now until they were not more than three inches high. suddenly the very young man let go of the big business man's arm and looked around to where the doctor was still leaning pensively against the table leg. the banker saw him speak swiftly to the big business man, but in so small a voice he could not catch the words. then both little figures turned towards the table, and the banker saw the very young man put his hands to his mouth and shout. and upward to him came the shrillest, tiniest little voice he had ever heard, yet a voice still embodying the characteristic intonation of the very young man. "hey, doctor!" came the words. "you'll never get here if you don't come now." the doctor looked up abruptly; he evidently heard the words and realized his situation. (he was by this time not more than an inch and a half in height.) he hesitated only a moment, and then, as the other two little figures waved their arms wildly, he began running towards them. for more than a minute he ran. the very young man started towards him, but the doctor waved him back, redoubling his efforts. when he arrived at the edge of the handkerchief, evidently he was nearly winded, for he stopped beside his friends, and stood breathing heavily. the banker leaned forwards, and could see the three little figures (they were not as big as the joint of his little finger) talking earnestly; the very young man was gesticulating wildly, pointing towards the ring. one of them made a start, but the others called him back. then they began waving their arms, and all at once the banker realized they were waving at him. he leaned down, and by their motions knew that something was wrong--that they wanted him to do something. trembling with fright, the banker left his chair and knelt upon the floor. the very young man made a funnel of his hands and shouted up: "it's too far away. we can't make it--we're too small!" the banker looked his bewilderment. then he thought suddenly of the spoon that he still held in his hand, and he put it down towards them. the three little figures ducked and scattered as the spoon in the banker's trembling fingers neared them. "not that--the ring. bring it closer. hurry--hurry!" shouted the very young man. the banker, leaning closer, could just hear the words. comprehending at last, he picked up the ring and laid it near the edge of the handkerchief. immediately the little figures ran over to it and began climbing up. the very young man was the first to reach it; the banker could see him vault upwards and land astraddle upon its top. the doctor was up in a moment more, and the two were reaching down their hands to help up the big business man. the banker slid the spoon carefully along the floor towards the ring, but the big business man waved it away. the banker laid the spoon aside, and when he looked at the ring again the big business man was up beside his companions, standing upright with them upon the top of the ring. the banker stared so long and intently, his vision blurred. he closed his eyes for a moment, and when he opened them again the little figures on the top of the ring had disappeared. the banker felt suddenly sick and faint in the closeness of the room. rising to his feet, he hurried to a window and threw up the sash. a gust of rain and wind beat against his face as he stood leaning on the sill. he felt much better after a few moments; and remembering his friends, he closed the window and turned back towards the ring. at first he thought he could just make them out, but when he got down on the floor close beside the ring, he saw nothing. almost unnerved, he sat down heavily upon the floor beside the handkerchief, leaning on one elbow. a corner of the handkerchief was turned back, and one side was ruffled where the wind from the opened window had blown it up. he smoothed out the handkerchief carefully. for some time the banker sat quiet, reclining uncomfortably upon the hard floor. the room was very still--its silence oppressed him. he stared stolidly at the ring, his head in a turmoil. the ring looked oddly out of place, lying over near one edge of the handkerchief; he had always seen it in the center before. abruptly he put out his hand and picked it up. then remembrance of the doctor's warning flooded over him. in sudden panic he put the ring down again, almost in the same place at the edge of the handkerchief. trembling all over, he looked at his watch; it was a quarter to nine. he rose stiffly to his feet and sank into his chair. after a moment he lighted a cigar. the handkerchief lay at his feet; he could just see the ring over the edge of his knees. for a long time he sat staring. the striking of a church clock nearby roused him. he shook himself together and blinked at the empty room. in his hand he held an unlighted cigar; mechanically he raised it to his lips. the sound of the church bells died away; the silence of the room and the loneliness of it made him shiver. he looked at his watch again. ten o'clock! still another hour to wait and watch, and then he could take the ring back to the museum. he glanced down at the ring; it was still lying by the edge of the handkerchief. again the banker fell into a stupor as he stared at the glistening gold band lying on the floor at his feet. how lonely he felt! yet he was not alone, he told himself. his three friends were still there, hardly two feet from the toe of his shoe. he wondered how they were making out. would they come back any moment? would they ever come back? and then the banker found himself worrying because the ring was not in the center of the handkerchief. he felt frightened, and he wondered why. again he looked at his watch. they had been gone more than two hours now. swiftly he stooped, and lifting the ring, gazed at it searchingly, holding it very close to his eyes. then he carefully put it down in the center of the handkerchief, and lay back in his chair with a long sigh of relief. it was all right now; just a little while to wait, and then he could take it back to the museum. in a moment his eyes blinked, closed, and soon he was fast asleep, lying sprawled out in the big leather chair and breathing heavily. chapter xiii perilous ways the very young man sat on the floor, between his two friends at the edge of the handkerchief, and put the first pellets of the drug to his tongue. his heart was beating furiously; his forehead was damp with the sweat of excitement and of fear. the pellets tasted sweet, and yet a little acrid. he crushed them in his mouth and swallowed them hastily. in the silence of the room, the ticking of his watch suddenly sounded very loud. he raised his arm and looked at its face; it was just ten minutes past eight. he continued to stare at its dial, wondering why nothing was happening to him. then all at once the figures on the watch became very sharp and vivid; he could see them with microscopic clearness. a buzzing sounded in his ears. he remembered having felt the same way just before he fainted. he drew a deep breath and looked around the room; it swam before his gaze. he closed his eyes and waited, wondering if he would faint. the buzzing in his head grew louder; a feeling of nausea possessed him. after a moment his head cleared; he felt better. then all at once he realized that the floor upon which he sat was moving. it seemed to be shifting out from under him in all directions. he sat with his feet flat upon the floor, his knees drawn close against his chin. and the floor seemed to be carrying his feet farther out; he constantly had to be pulling them back against him. he put one hand down beside him, and could feel his fingers dragging very slowly as the polished surface moved past. the noise in his head was almost gone now. he opened his eyes. before him, across the handkerchief the banker sat in his chair. he had grown enormously in size, and as the very young man looked he could see him and the chair growing steadily larger. he met the banker's anxious glance, and smiled up at him. then he looked at his two friends, sitting on the floor beside him. they alone, of everything within his range of vision, had grown no larger. the very young man thought of the belt around his waist. he put his hand to it, and found it tight as before. so, after all, they would not have to leave anything behind, he thought. the doctor rose to his feet and turned away, back under the huge table that loomed up behind him. the very young man got up, too, and stood beside the big business man, holding to him for support. his head felt strangely confused; his legs were weak and shaky. steadily larger grew the room and everything in it. the very young man turned his eyes up to the light high overhead. its great electric bulbs dazzled him with their brilliancy; its powerful glare made objects around as bright as though in daylight. after a moment the big business man's grip on his arm tightened. "god, it's weird!" he said in a tense whisper. "look!" before them spread a great, level, shining expanse of black, with the ring in its center--a huge golden circle. beyond the farther edge of the black they could see the feet of the banker, and the lower part of his legs stretching into the air far above them. the very young man looked up still higher, and saw the banker staring down at him, "good-by, my boy," said the banker. his voice came from far away in a great roar to the very young man's ears. "good-by, sir," said the very young man, and waved his hand. several minutes passed, and still the very young man stood holding to his companion, and watching the expanse of handkerchief widening out and the gleaming ring growing larger. then he thought of the doctor, and turned suddenly to look behind him. across the wide, glistening surface of the floor stood the doctor, leaning against the tremendous column that the very young man knew was the leg of the center-table. and as the very young man stood staring, he could see this distance between them growing steadily greater. a sudden fear possessed him, and he shouted to his friend. "good lord, suppose he can't make it!" said the big business man fearfully. "he's coming," answered the very young man. "he's got to make it." the doctor was running towards them now, and in a few moments he was beside them, breathing heavily. "close call, frank," said the big business man, shaking his head. "you were the one said we must keep together." the doctor was too much out of breath to answer. "this is worse," said the very young man. "look where the ring is." more than two hundred yards away across the black expanse of silk handkerchief lay the ring. "it's almost as high as our waist now, and look how far it is!" added the very young man excitedly. "it's getting farther every minute," said the big business man. "come on," and he started to run towards the ring. "i can't make it. it's too far!" shouted the doctor after him. the big business man stopped short. "what'll we do?" he asked. "we've got to get there." "that ring will be a mile away in a few minutes, at the rate it's going," said the very young man. "we'll have to get him to move it over here," decided the doctor, looking up into the air, and pointing. "gee, i never thought of that!" said the very young man. "oh, great scott, look at him!" out across the broad expanse of handkerchief they could see the huge white face of their friend looming four or five hundred feet in the air above them. it was the most astounding sight their eyes had ever beheld; yet so confused were they by the flood of new impressions to which they were being subjected that this colossal figure added little to their surprise. "we must make him move the ring over here," repeated the doctor. "you'll never make him hear you," said the big business man, as the very young man began shouting at the top of his voice. "we've got to," said the very young man breathlessly. "look at that ring. we can't get to it now. we're stranded here. good lord! what's the matter with him--can't he see us?" he added, and began shouting again. "he's getting up," said the doctor. they could see the figure of the banker towering in the air a thousand feet above the ring, and then with a swoop of his enormous face come down to them as he knelt upon the floor. with his hands to his mouth, the very young man shouted up: "it's too far away. we can't make it--we're too small." they waited. suddenly, without warning, a great wooden oval bowl fifteen or twenty feet across came at them with tremendous speed. they scattered hastily in terror. "not that--the ring!" shouted the very young man, as he realized it was the spoon in the banker's hand that had frightened them. a moment more and the ring was before them, lying at the edge of the handkerchief--a circular pit of rough yellow rock breast high. they ran over to it and climbed upon its top. another minute and the ring had grown until its top became a narrow curving path upon which they could stand. they got upon their feet and looked around curiously. "well, we're here," remarked the very young man. "everything's o.k. so far. let's get right around after that scratch." "keep together," cautioned the doctor, and they started off along the path, following its inner edge. as they progressed, the top of the ring steadily became broader; the surface underfoot became rougher. the big business man, walking nearest the edge, pulled his companion towards him. "look there!" he said. they stood cautiously at the edge and looked down. beneath them the ring bulged out. over the bulge they could see the black of the handkerchief--a sheer hundred-feet drop. the ring curved sharply to the left; they could follow its wall all the way around; it formed a circular pit some two hundred and fifty feet in diameter. a gentle breeze fanned their faces as they walked. the very young man looked up into the gray of the distance overhead. a little behind, over his shoulder he saw above him in the sky a great, gleaming light many times bigger than the sun. it cast on the ground before him an opaque shadow, blurred about the edges. "pretty good day, at that," remarked the very young man, throwing out his chest. the doctor laughed. "it's half-past eight at night," he said. "and if you'll remember half an hour ago, it's a very stormy night, too." the big business man stopped short in his walk. "just think," he said pointing up into the gray of the sky, with a note of awe in his voice, "over there, not more than fifteen feet away, is a window, looking down towards the gaiety theater and broadway." the very young. man looked bewildered. "that window's a hundred miles away," he said positively. "fifteen feet," said the big business man. "just beyond the table." "it's all in the viewpoint" said the doctor, and laughed again. they had recovered their spirits by now, the very young man especially seeming imbued with the enthusiasm of adventure. the path became constantly rougher as they advanced. the ground underfoot--a shaggy, yellow, metallic ore--was strewn now with pebbles. these pebbles grew larger farther on, becoming huge rocks and bowlders that greatly impeded their progress. they soon found it difficult to follow the brink of the precipice. the path had broadened now so that its other edge was out of sight, for they could see only a short distance amid the bowlders that everywhere tumbled about, and after a time they found themselves wandering along, lost in the barren waste. "how far is the scratch, do you suppose?" the very young man wanted to know. they stopped and consulted a moment; then the very young man clambered up to the top of a rock. "there's a range of hills over there pretty close," he called down to them. "that must be the way." they had just started again in the direction of the hills when, almost without warning, and with a great whistle and roar, a gale of wind swept down upon them. they stood still and looked at each other with startled faces, bracing with their feet against its pressure. "oh, golly, what's this?" cried the very young man, and sat down suddenly upon the ground to keep from being blown forward. the wind increased rapidly in violence until, in a moment, all three of the men were crouching upon the ground for shelter. "great scott, this is a tornado!" ejaculated the big business man. his words were almost lost amid the howling of the blast as it swept across the barren waste of rocks. "rogers never told us anything about this. it's getting worse every minute. i----" a shower of pebbles and a great cloud of metallic dust swept past, leaving them choking and gasping for breath. the very young man got upon his hands and knees. "i'm going over there," he panted. "it's better." chapter xiv strange experiences led by the very young man, the three crawled a few yards to where a cluster of bowlders promised better shelter. huddled behind this mass of rock, they found themselves protected in a measure from the violence of the storm. lying there, they could see yellowish-gray clouds of sand go sweeping by, with occasionally a hail of tiny pebbles, blowing almost horizontal. overhead, the sky was unchanged. not a vestige of cloud was visible, only the gray-blue of an immense distance, with the huge gleaming light, like an enormous sun, hung in its center. the very young man put his hand on the doctor's arm. "it's going down," he said. hardly were the words out of his mouth before, with even less warning than it began, the gale abruptly ceased. there remained only the pleasantly gentle breeze of a summer afternoon blowing against their faces. and this came from almost an opposite direction to the storm. the three men looked at one another in amazement. "well, i'll be----" ejaculated the very young man. "what next?" they waited for some time, afraid to venture out from the rocks among which they had taken refuge. then, deciding that the storm, however unexplainable, was over for the time at least, they climbed to their feet and resumed their journey with bruised knees, but otherwise none the worse for the danger through which they had passed. after walking a short distance, they came up a little incline, and before them, hardly more than a quarter of a mile away, they could see a range of hills. "the scratch must be behind those hills," said the very young man, pointing. "it's a long distance," said the big business man thoughtfully. "we're still growing smaller--look." their minds had been so occupied that for some time they had forgotten the effect of the drug upon their stature. as they looked about them now they could see the rocks around them still increasing steadily in size, and could feel the ground shifting under their feet when they stood still. "you're right; we're getting smaller," observed the very young man. "how long before we'll stop, do you suppose?" the doctor drew the chemist's memoranda from the pouch of his belt. "it says about five or six hours for the first four pellets," he read. the very young man looked at his watch. "quarter to nine. we've been less than an hour yet. come on, let's keep going," and he started walking rapidly forward. they walked for a time in silence. the line of hills before them grew visibly in size, and they seemed slowly to be nearing it. "i've been thinking," began the doctor thoughtfully as he glanced up at the hills. "there's one theory of rogers's that was a fallacy. you remember he was quite positive that this change of stature became steadily more rapid, until it reached its maximum rate and then remained constant. if that were so we should probably be diminishing in size more rapidly now than when we first climbed on to the ring. if we had so much trouble getting to the ring then"--he smiled at the remembrance of their difficulty--"i don't see how we could ever get to those hills now." "gee, that's so," said the very young man. "we'd never be able to get anywhere, would we?" "how do you figure it works?" asked the big business man. the doctor folded up the paper and replaced it in his belt. "i don't know," he answered. "i think probably it proceeds in cycles, like the normal rate of growth--times of rapid progress succeeded by periods of comparative inactivity." "i never knew people grew that way," observed the very young man. "they do," said the doctor. "and if these drugs produce the same effect we----" he got no further, for suddenly the earth seemed to rise swiftly under them, and they were thrown violently to the ground. the very young man, as he lay prone, looked upward, and saw the sunlike light above fall swiftly down across the sky and disappear below the horizon, plunging the world about them into the gloom of a semi-twilight. a wind, fiercer than before, swept over them with a roar. "the end of the world," murmured the very young man to himself. and he wondered why he was not frightened. then came the feeling of an extraordinary lightness of body, as though the ground were dropping away from under him. the wind abruptly ceased blowing. he saw the ball of light rise swiftly from the horizon and mount upward in a great, gleaming arc to the zenith, where again it hung motionless. the three men lay quiet, their heads reeling. then the very young man sat up dizzily and began feeling himself all over. "there's nothing wrong with me," he said lugubriously, meeting the eyes of his friends who apparently were also more surprised than hurt. "but--oh, my gosh, the whole universe went nutty!" he added to himself in awe. "what did that?" asked the big business man. he climbed unsteadily to his feet and sat upon a rock, holding his head in his hands. the doctor was up in a moment beside him. "we're not hurt," he said, looking at his companions. "don't let's waste any more time--let's get into that valley." the very young man could see by his manner that he knew or guessed what had happened. "but say; what----" began the very young man. "come on," interrupted the doctor, and started walking ahead swiftly. there was nothing for his two friends to do but to follow. they walked in silence, in single file, picking their way among the rocks. for a quarter of an hour or more they kept going, until finally they came to the ridge of hills, finding them enormous rocks, several hundred feet high, strewn closely together. "the valley must be right beyond," said the doctor. "come on." the spaces between these huge rocks were, some of them, fifty feet or more in width. inside the hills the travelers found the ground even rougher than before, and it was nearly half an hour before they emerged on the other side. instead of the shallow valley they expected to find, they came upon a precipice--a sheer drop into a tremendous cañon, half as wide possibly as it was deep. they could see down to its bottom from where they stood--the same rocky, barren waste as that through which they had been traveling. across the cañon, on the farther side, lay another line of hills. "it's the scratch all right," said the very young man, as they stopped near the brink of the precipice, "but, holy smoke! isn't it big?" "that's two thousand feet down there," said the big business man, stepping cautiously nearer to the edge. "rogers didn't say it was so deep." "that's because we've been so much longer getting here," explained the doctor. "how are we going to get down?" asked the very young man as he stood beside the big business man within a few feet of the brink. "it's getting deeper every minute, don't forget that." the big business man knelt down and carefully approached to the very edge of the precipice. then, as he looked over, he got upon his feet with a laugh of relief. "come here," he said. they joined him at the edge and, looking over, could see that the jagged roughness of the wall made the descent, though difficult, not exceptionally hazardous. below them, not more than twenty feet, a wide ledge jutted out, and beyond that they could see other similar ledges and crevices that would afford a foothold. "we can get down that," said the very young man. "there's an easy place," and he pointed farther along the brink, to where a break in the edge seemed to offer a means of descent to the ledge just below. "it's going to be a mighty long climb down," said the big business man. "especially as we're getting smaller all the time. i wonder," he added thoughtfully, "how would it be if we made ourselves larger before we started. we could get big enough, you know, so that it would only be a few hundred feet down there. then, after we got down, we could get small again." "that's a thought," said the very young man. the doctor sat down somewhat wearily, and again took the papers from his belt. "the idea is a good one," he said. "but there's one thing you overlook. the larger we get, the smoother the wall is going to be. look, can't you see it changing every moment?" it was true. even in the short time since they had first looked down, new crevices had opened up. the descent, though longer, was momentarily becoming less dangerous. "you see," continued the doctor, "if the valley were only a few hundred feet deep, the precipice might then be so sheer we could not trust ourselves to it at all." "you're right," observed the big business man. "well, it's not very hard to get down now," said the very young man. "let's get going before it gets any deeper. say," he added, "how about stopping our size where it is? how would that work?" the doctor was reading the papers he held in his hand. "i think," he said, "it would be our wisest course to follow as closely as possible what rogers tells us to do. it may be harder, but i think we will avoid trouble in the end." "we could get lost in size just as easily as in space, couldn't we?" the big business man put in. "that's a curious idea, isn't it?" "it's true," agreed the doctor. "it is something we must guard against very carefully." "well, come on then, let's get going," said the very young man, pulling the doctor to his feet. the big business man glanced at his watch. "twenty to ten," he said. then he looked up into the sky. "one hour and a half ago," he added sentimentally, "we were up there. what will another hour bring--i wonder?" "nothing at all," said the very young man, "if we don't ever get started. come on." he walked towards the place he had selected, followed by his companions. and thus the three adventurers began their descent into the ring. chapter xv the valley of the sacrifice for the first half-hour of their climb down into the valley of the scratch, the three friends were too preoccupied with their own safety to talk more than an occasional sentence. they came upon many places that at first glance appeared impassable, or at least sufficiently hazardous to cause them to hesitate, but in each instance the changing contour of the precipice offered some other means of descent. after thirty minutes of arduous effort, the big business man sat down suddenly upon a rock and began to unlace his shoes. "i've got to rest a while," he groaned. "my feet are in terrible shape." his two companions were glad of the opportunity to sit with him for a moment. "gosh, i'm all in, too!" said the very young man with a sigh. they were sitting upon a ledge about twenty feet wide, with the wall down which they had come at their back. "i'll swear that's as far down there as it ever was," said the big business man, with a wave of his hand towards the valley below them. "further," remarked the very young man. "i've known that right along." "that's to be expected," said the doctor. "but we're a third the way down, just the same; that's the main thing." he glanced up the rocky, precipitous wall behind them. "we've come down a thousand feet, at least. the valley must be three thousand feet deep or more now." "say, how deep does it get before it stops?" inquired the very young man. the doctor smiled at him quietly. "rogers's note put it about twelve thousand," he answered. "it should reach that depth and stop about"--he hesitated a moment, calculating--"about two o'clock," he finished. "some climb," commented the very young man. "we could do this a lot better than we're doing it, i think." for some time they sat in silence. from where they sat the valley had all the appearance of a rocky, barren cañon of their own world above, as it might have looked on the late afternoon of a cloudless summer day. a gentle breeze was blowing, and in the sky overhead they could still see the huge light that for them was the sun. "the weather is certainly great down here anyway," observed the very young man, "that's one consolation." the big business man had replaced his shoes, taken a swallow of water, and risen to his feet, preparing to start downward again, when suddenly they all noticed a curious swaying motion, as though the earth were moving under them. "now what?" ejaculated the very young man, standing up abruptly, with his feet spread wide apart. the ground seemed pressing against his feet as if he were weighted down with a heavy load. and he felt a little also as though in a moving train with a side thrust to guard against. the sun was no longer visible, and the valley was plunged in the semidarkness of twilight. a strong wind sprang up, sweeping down upon them from above. the very young man and the big business man looked puzzled; the doctor alone of the three seemed to understand what was happening. "he's moving the ring," he explained, with a note of apprehension in his voice. "oh," ejaculated the big business man, comprehending at last, "so that's the----" the very young man standing with his back to the wall and his legs spread wide looked hastily at his watch. "moving the ring? why, damn it----" he began impetuously. the big business man interrupted him. "look there, look!" he almost whispered, awestruck. the sky above the valley suddenly had become suffused with red. as they watched it seemed to take form, appearing no longer space, but filled with some enormous body of reddish color. in one place they could see it broken into a line of gray, and underneath the gray, two circular holes of light gleamed down at them. the doctor shuddered and closed his eyes; his two friends stared upward, fascinated into immobility. "what--is--that?" the very young man whispered. before he could be answered, the earth swayed under them more violently than before. the red faded back out of the sky, and the sun appeared sweeping up into the zenith, where it hung swaying a moment and then poised motionless. the valley was flooded again with light; the ground steadied under them and became quiet. the wind died rapidly away, and in another moment it was as though nothing unusual had occurred. for a time the three friends stood silent, too astonished for words at this extraordinary experience. the doctor was the first to recover himself. "he moved the ring," he said hurriedly. "that's twice. we must hurry." "it's only quarter past ten. we told him not till eleven," protested the very young man. "even that is too soon for safety," said the doctor back over his shoulder, for already he had started downward. it was nearly twelve o'clock when they stopped again for rest. at this time the valley appeared about seven or eight thousand feet deep: they estimated themselves to be slightly more than half-way down. from eleven until twelve they had momentarily expected some disturbing phenomena attendant upon the removal of the ring by the banker from the clubroom to its place in the museum. but nothing unusual had occurred. "he probably decided to leave it alone for a while," commented the big business man, as they were discussing the matter. "glad he showed that much sense." "it would not bother us much now," the doctor replied. "we're too far down. see how the light is changing." the sky showed now only as a narrow ribbon of blue between the edges of the cañon's walls. the sun was behind the wall down which they were climbing, out of sight, and throwing their side of the valley into shadow. and already they could begin to see a dim phosphorescence glowing from the rocks near at hand. the very young man, sitting beside the doctor, suddenly gripped his friend by the arm. "a bird," he said, pointing down the valley. "see it there?" from far off they could see a bird coming up the center of the valley at a height apparently almost level with their own position, and flying towards them. they watched it in silence as it rapidly approached. "great scott, it's big!" muttered the big business man in an undertone. as the bird came closer they saw it was fully fifty feet across the wings. it was flying straight down the valley at tremendous speed. when it was nearly opposite them they heard a familiar "cheep, cheep," come echoing across the valley. "the sparrow," whispered the very young man. "oh, my gosh, look how big it is!" in another moment it had passed them; they watched in silence until it disappeared in the distance. "well," said the very young man, "if that had ever seen us----" he drew a long breath, leaving the rest to the imagination of his hearers. "what a wonderful thing!" said the big business man, with a note of awe in his voice. "just think--that sparrow when we last saw it was infinitesimally small." the doctor laughed. "it's far smaller now than it was then," he said. "only since we last saw it we have changed size to a much greater extent than it has." "foolish of us to have sent it in here," remarked the big business man casually. "suppose that----" he stopped abruptly. the very young man started hastily to his feet. "oh, golly!" he exclaimed as the same thought occurred to him. "that lizard----" he looked about him wildly. "it was foolish perhaps." the doctor spoke quietly. "but we can't help it now. the sparrow has gone. that lizard may be right here at our feet"--the very young man jumped involuntarily--"and so small we can't see it," the doctor finished with a smile. "or it may be a hundred miles away and big as a dinosaur." the very young man shuddered. "it was senseless of us to let them get in here anyway," said the big business man. "that sparrow evidently has stopped getting smaller. do you realize how big it will be to us, after we've diminished a few hundred more times?" "we needn't worry over it," said the doctor. "even if we knew the lizard got into the valley the chances of our seeing it here are one in a million. but we don't even know that. if you'll remember it was still some distance away from the scratch when it became invisible; i doubt very much if it even got there. no, i think probably we'll never see it again." "i hope not," declared the very young man emphatically. for another hour they climbed steadily downward, making more rapid progress than before, for the descent became constantly less difficult. during this time they spoke little, but it was evident that the very young man, from the frequent glances he threw around, never for a moment forgot the possibility of encountering the lizard. the sparrow did not return, although for that, too, they were constantly on the look-out. it was nearly half-past one when the big business man threw himself upon the ground exhausted. the valley at this time had reached a depth of over ten thousand feet. it was still growing deeper, but the travelers had made good progress and were not more than fifteen hundred feet above its bottom. they had been under tremendous physical exertion for over five hours, too absorbed in their strange experiences to think of eating, and now all three agreed it was foolish to attempt to travel farther without food and rest. "we had better wait here an hour or two," the doctor decided. "our size will soon remain constant and it won't take us long to get down after we've rested." "i'm hungry," suggested the very young man, "how about you?" they ate and drank sparingly of the little store they had brought with them. the doctor would not let them have much, both because he wanted to conserve their supply, and because he knew in their exhausted condition it would be bad for them to eat heartily. it was about two o'clock when they noticed that objects around them no longer were increasing in size. they had finished their meal and felt greatly refreshed. "things have stopped growing," observed the very young man. "we've done four pills' worth of the journey anyway," he added facetiously. he rose to his feet, stretching. he felt sore and bruised all over, but with the meal and a little rest, not particularly tired. "i move we go on down now," he suggested, walking to the edge of the huge crevice in which they were sitting. "it's only a couple of thousand feet." "perhaps we might as well," agreed the doctor, rising also. "when we get to the floor of the valley, we can find a good spot and turn in for the night." the incongruity of his last words with the scene around made the doctor smile. overhead the sky still showed a narrow ribbon of blue. across the valley the sunlight sparkled on the yellowish crags of the rocky wall. in the shadow, on the side down which they were climbing, the rocks now shone distinctly phosphorescent, with a peculiar waviness of outline. "not much like either night or day, is it?" added the doctor. "we'll have to get used to that." they started off again, and in another two hours found themselves going down a gentle rocky slope and out upon the floor of the valley. "we're here at last," said the big business man wearily. the very young man looked up the great, jagged precipice down which they had come, to where, far above, its edge against the strip of blue marked the surface of the ring. "some trip," he remarked. "i wouldn't want to tackle that every day." "four o'clock," said the doctor, "the light up there looks just the same. i wonder what's happened to george." neither of his companions answered him. the big business man lay stretched full length upon the ground near by, and the very young man still stood looking up the precipice, lost in thought. "what a nice climb going back," he suddenly remarked. the doctor laughed. "don't let's worry about that, jack. if you remember how rogers described it, getting back is easier than getting in. but the main point now," he added seriously, "is for us to make sure of getting down to arite as speedily as possible." the very young man surveyed the barren waste around them in dismay. the floor of the valley was strewn with even larger rocks and bowlders than those on the surface above, and looked utterly pathless and desolate. "what do we do first?" he asked dubiously. "first," said the doctor, smiling at the big business man, who lay upon his back staring up into the sky and paying no attention to them whatever, "i think first we had better settle ourselves for a good long rest here." "if we stop at all, let's sleep a while," said the very young man. "a little rest only gets you stiff. it's a pretty exposed place out here though, isn't it, to sleep?" he added, thinking of the sparrow and the lizard. "one of us will stay awake and watch," answered the doctor. chapter xvi the pit of darkness at the suggestion of the very young man they located without much difficulty a sort of cave amid the rocks, which offered shelter for their rest. taking turns watching, they passed eight hours in fair comfort, and by noon next day, after another frugal meal they felt thoroughly refreshed and eager to continue the journey. "we sure are doing this classy," observed the very young man. "think of rogers--all he could do was fall asleep when he couldn't stay awake any more. gosh, what chances he took!" "we're playing it safe," agreed the big business man. "but we mustn't take it too easy," added the doctor. the very young man stretched himself luxuriously and buckled his belt on tighter. "well, i'm ready for anything," he announced. "what's next?" the doctor consulted his papers. "we find the circular pit rogers made in the scratch and we descend into it. we take twelve more pills at the edge of the pit," he said. the very young man leaped to the top of a rock and looked out over the desolate waste helplessly. "how are we going to find the pit?" he asked dubiously. "it's not in sight, that's sure." "it's down there--about five miles," said the doctor. "i saw it yesterday as we came down." "that's easy," said the very young man, and he started off enthusiastically, followed by the others. in less than two hours they found themselves at the edge of the pit. it appeared almost circular in form, apparently about five miles across, and its smooth, shining walls extended almost perpendicularly down into blackness. somewhat awed by the task confronting them in getting down into this abyss, the three friends sat down near its brink to discuss their plan of action. "we take twelve pills here," said the doctor. "that ought to make us small enough to climb down into that." "do you think we need so many?" asked the big business man thoughtfully. "you know, frank, we're making an awful lot of work for ourselves, playing this thing so absolutely safe. think of what a distance down that will be after we have got as small as twelve pills will make us. it might take us days to get to the bottom." "how did rogers get down?" the very young man wanted to know. "he took the twelve pills here," the doctor answered. "but as i understand it, he fell most of the way down while he was still big, and then got small afterwards at the bottom." this from the big business man. "i don't know how about you," said the very young man drily, "but i'd much rather take three days to walk down than fall down in one day." the doctor smiled. "i still think," he said, "that we had better stick to the directions rogers left us. then at least there is no danger of our getting lost in size. but i agree with you, jack. i'd rather not fall down, even if it takes longer to walk." "i wonder----" began the big business man. "you know i've been thinking--it does seem an awful waste of energy for us to let ourselves get smaller than absolutely necessary in climbing down these places. maybe you don't realize it." "i do," said the very young man, looking sorrowfully at the ragged shoes on his feet and the cuts and bruises on his legs. "what i mean is----" persisted the big business man. "how far do you suppose we have actually traveled since we started last night?" "that's pretty hard to estimate," said the doctor. "we have walked perhaps fifteen miles altogether, besides the climb down. i suppose we actually came down five or six thousand feet." "and at the size we are now it would have been twelve thousand feet down, wouldn't it?" "yes," answered the doctor, "it would." "and just think," went on the big business man, "right now, based on the size we were when we began, we've only gone some six feet altogether from the place we started." "and a sixteenth of an inch or less since we left the surface of the ring," said the doctor smiling. "gee, that's a weird thought," the very young man said, as he gazed in awe at the lofty heights about them. "i've been thinking," continued the big business man. "you say we must be careful not to get lost in size. well, suppose instead of taking twelve pills here, we only take six. that should be enough to get us started--possibly enough to get us all the way down. then before we moved at all we could take the other six. that would keep it straight, wouldn't it?" "great idea," said the very young man. "i'm in favor of that." "it sounds feasible--certainly if we can get all the way down with six pills we will save a lot of climbing." "if six aren't enough, we can easily take more," added the big business man. and so they decided to take only six pills of the drug and to get down to the bottom of the pit, if possible, without taking more. the pit, as they stood looking down into it now, seemed quite impossible of descent, for its almost perpendicular wall was smooth and shining as polished brass. they took the drug, standing close together at the edge of the pit. immediately began again the same crawling sensation underfoot, much more rapid this time, while all around them the rocks began very rapidly increasing in size. the pit now seemed widening out at an astounding rate. in a few minutes it had broadened so that its opposite side could not be seen. the wall at the brink of which they stood had before curved in a great sweeping arc to enclose the circular hole; now it stretched in a nearly straight, unbroken line to the right and left as far as they could see. beneath them lay only blackness; it was as though they were at the edge of the world. "good god, what a place to go down into," gasped the big business man, after they had been standing nearly half an hour in silence, appalled at the tremendous changes taking place around them. for some time past the wall before them had become sufficiently indented and broken to make possible their descent. it was the doctor who first realized the time--or perhaps it should be said, the size--they were losing by their inactivity; and when with a few crisp words he brought them to themselves, they immediately started downward. for another six hours they traveled downward steadily, stopping only once to eat. the descent during this time was not unlike that down the side of the valley, although towards the last it began rapidly to grow less precipitous. they now found themselves confronted frequently with gentle slopes downward, half a mile or more in extent, and sometimes by almost level places, succeeded by another sharp descent. during this part of the trip they made more rapid progress than at any time since starting, the very young man in his enthusiasm at times running forward and then sitting down to wait for the others to overtake him. the light overhead gradually faded into the characteristic luminous blackness the chemist had described. as it did so, the phosphorescent quality of the rocks greatly increased, or at least became more noticeable, so that the light illuminating the landscape became hardly less in volume, although totally different in quality. the ground underfoot and the rocks themselves had been steadily changing. they had lost now almost entirely the yellowishness, metal look, and seemed to have more the quality of a gray opaque glass, or marble. they appeared rather smoother, too, than before, although the huge bowlders and loosely strewn rocks and pebbles still remained the characteristic feature of the landscape. the three men were still diminishing in size; in fact, at this time the last dose of the drug seemed to have attained its maximum power, for objects around them appeared to be growing larger at a dizzying rate. they were getting used to this effect, however, to a great extent, and were no longer confused by the change as they had been before. it was the big business man who first showed signs of weakening, and at the end of six hours or more of steady--and, towards the end, extremely rapid--traveling he finally threw himself down and declared he could go no farther. at this point they rested again several hours, taking turns at watch, and each of them getting some measure of sleep. of the three, the very young man appeared in the best condition, although possibly it was his enthusiasm that kept him from admitting even to himself any serious physical distress. it was perhaps ten or twelve hours after they had taken the six pills that they were again ready to start downward. before starting the three adventurers discussed earnestly the advisability of taking the other six pills. the action of the drug had ceased some time before. they decided not to, since apparently there was no difficulty facing them at this part of the journey, and decreasing their stature would only immeasurably lengthen the distance they had to go. they had been traveling downward, through a barren land that now showed little change of aspect, for hardly more than another hour, when suddenly, without warning, they came upon the tremendous glossy incline that they had been expecting to reach for some time. the rocks and bowlders stopped abruptly, and they found at their feet, sloping downward at an angle of nearly forty-five degrees, a great, smooth plane. it extended as far as they could see both to the right and left and downward, at a slightly lessening angle, into the luminous darkness that now bounded their entire range of vision in every direction. this plane seemed distinctly of a different substance than anything they had hitherto encountered. it was, as the chemist had described it, apparently like a smooth black marble. yet it was not so smooth to them now as he had pictured it, for its surface was sufficiently indented and ridged to afford foothold. they started down this plane gingerly, yet with an assumed boldness they were all of them far from feeling. it was slow work at first, and occasionally one or the other of them would slide headlong a score of feet, until a break in the smoothness brought him to a stop. their rubber-soled shoes stood them in good stead here, for without the aid given by them this part of the journey would have been impossible. for several hours they continued this form of descent. the incline grew constantly less steep, until finally they were able to walk down it quite comfortably. they stopped again to eat, and after traveling what seemed to them some fifteen miles from the top of the incline they finally reached its bottom. they seemed now to be upon a level floor--a ground of somewhat metallic quality such as they had become familiar with above. only now there were no rocks or bowlders, and the ground was smoother and with a peculiar corrugation. on one side lay the incline down which they had come. there was nothing but darkness to be seen in any other direction. here they stopped again to rest and recuperate, and then they discussed earnestly their next movements. the doctor, seated wearily upon the ground, consulted his memoranda earnestly. the very young man sat close beside him. as usual the big business man lay prone upon his back nearby, waiting for their decision. "rogers wasn't far from a forest when he got here," said the very young man, looking sidewise at the papers in the doctor's hand. "and he speaks of a tiny range of hills; but we can't see anything from here." "we may not be within many miles of where rogers landed," answered the doctor. "no reason why we should be, at that, is there? do you think we'll ever find arite?" "don't overlook the fact we've got six more pills to take here," called the big business man. "that's just what i was considering," said the doctor thoughtfully. "there's no use our doing anything until we have attained the right size. those hills and the forest and river we are looking for might be here right at our feet and we couldn't see them while we are as big as this." "we'd better take the pills and stay right here until their action wears off. i'm going to take a sleep," said the big business man. "i think we might as well all sleep," said the doctor. "there could not possibly be anything here to harm us." they each took the six additional pills without further words. physically exhausted as they were, and with the artificial drowsiness produced by the drug, they were all three in a few moments fast asleep. chapter xvii the welcome of the master it was nearly twelve hours later, as their watches showed them, that the first of the weary adventurers awoke. the very young man it was who first opened his eyes with a confused sense of feeling that he was in bed at home, and that this was the momentous day he was to start his journey into the ring. he sat up and rubbed his eyes vigorously to see more clearly his surroundings. beside him lay his two friends, fast asleep. with returning consciousness came the memory of the events of the day and night before. the very young man sprang to his feet and vigorously awoke his companions. the action of the drug again had ceased, and at first glance the scene seemed to have changed very little. the incline now was some distance away, although still visible, stretching up in a great arc and fading away into the blackness above. the ground beneath their feet still of its metallic quality, appeared far rougher than before. the very young man bent down and put his hand upon it. there was some form of vegetation there, and, leaning closer, he could see what appeared to be the ruins of a tiny forest, bent and trampled, the tree-trunks no larger than slender twigs that he could have snapped asunder easily between his fingers. "look at this," he exclaimed. "the woods--we're here." the others knelt down with him. "be careful," cautioned the doctor. "don't move around. we must get smaller." he drew the papers from his pocket. "rogers was in doubt about this quantity to take," he added. "we should be now somewhere at the edge or in the forest he mentions. yet we may be very far from the point at which he reached the bottom of that incline. i think, too, that we are somewhat larger than he was. probably the strength of our drug differs from his to some extent." "how much should we take next, i wonder?" said the big business man as he looked at his companions. the doctor took a pill and crushed it in his hand. "let us take so much," he said, indicating a small portion of the powder. the others each crushed one of the pills and endeavored to take as nearly as possible an equal amount. "i'm hungry," said the very young man. "can we eat right after the powder?" "i don't think that should make any difference," the doctor answered, and so accustomed to the drug were they now that, quite nonchalantly, they sat down and ate. after a few moments it became evident that in spite of their care the amounts of the drug they had taken were far from equal. before they had half finished eating, the very young man was hardly more than a third the size of the doctor, with the big business man about half-way between. this predicament suddenly struck them as funny, and all three laughed heartily at the effect of the drug. "hey, you, hurry up, or you'll never catch me," shouted the very young man gleefully. "gosh, but you're big!" he reached up and tried to touch the doctor's shoulder. then, seeing the huge piece of chocolate in his friend's hand and comparing it with the little one in his own, he added: "trade you chocolate. that's a regular meal you got there." "that's a real idea," said the big business man, ceasing his laughter abruptly. "do you know, if we ever get really low on food, all we have to do is one of us stay big and his food would last the other two a month." "fine; but how about the big one?" asked the very young man, grinning. "he'd starve to death on that plan, wouldn't he?" "well, then he could get much smaller than the other two, and they could feed him. it's rather involved, i'll admit, but you know what i mean," the big business man finished somewhat lamely. "i've got a much better scheme than that," said the very young man. "you let the food stay large and you get small. how about that?" he added triumphantly. then he laid carefully on the ground beside him a bit of chocolate and a few of the hard crackers they were eating. "stay there, little friends, when you grow up, i'll take you back," he added in a gleeful tone of voice. "strange that should never have occurred to us," said the doctor. "it's a perfect way of replenishing our food supply," and quite seriously both he and the big business man laid aside some of their food. "thank me for that brilliant idea," said the very young man. then, as another thought occurred to him, he scratched his head lugubriously. "wouldn't work very well if we were getting bigger, would it? don't let's ever get separated from any food coming out." the doctor was gigantic now in proportion to the other two, and both he and the big business man took a very small quantity more of the drug in an effort to equalize their rate of bodily reduction. they evidently hit it about right, for no further change in their relative size occurred. all this time the vegetation underneath them had been growing steadily larger. from tiny broken twigs it grew to sticks bigger than their fingers, then to the thickness of their arms. they moved slightly from time to time, letting it spread out from under them, or brushing it aside and clearing a space in which they could sit more comfortably. still larger it grew until the tree-trunks, thick now almost as their bodies, were lying broken and twisted, all about them. over to one side they could see, half a mile away, a place where the trees were still standing--slender saplings, they seemed, growing densely together. in half an hour more the very young man announced he had stopped getting smaller. the action of the drug ceased in the others a few minutes later. they were still not quite in their relative sizes, but a few grains of the powder quickly adjusted that. they now found themselves near the edge of what once was a great forest. huge trees, whose trunks measured six feet or more in diameter, lay scattered about upon the ground; not a single one was left standing. in the distance they could see, some miles away, where the untrodden forest began. they had replaced the food in their belts some time before, and now again they were ready to start. suddenly the very young man spied a huge, round, whitish-brown object lying beside a tree-trunk near by. he went over and stood beside it. then he called his friends excitedly. it was irregularly spherical in shape and stood higher than his knees--a great jagged ball. the very young man bent down, broke off a piece of the ball, and, stuffing it into his mouth, began chewing with enthusiasm. "now, what do you think of that?" he remarked with a grin. "a cracker crumb i must have dropped when we first began lunch!" they decided now to make for the nearest part of the unbroken forest. it was two hours before they reached it, for among the tangled mass of broken, fallen trees their progress was extremely difficult and slow. once inside, among the standing trees, they felt more lost than ever. they had followed implicitly the chemist's directions, and in general had encountered the sort of country they expected. nevertheless, they all three realized that it was probable the route they had followed coming in was quite different from that taken by the chemist; and in what direction lay their destination, and how far, they had not even the vaguest idea, but they were determined to go on. "if ever we find this city of arite, it'll be a miracle sure," the very young man remarked as they were walking along in silence. they had gone only a short distance farther when the big business man, who was walking in front, stopped abruptly. "what's that?" he asked in a startled undertone. they followed the direction of his hand, and saw, standing rigid against a tree-trunk ahead, the figure of a man little more than half as tall as themselves, his grayish body very nearly the color of the blue-gray tree behind him. the three adventurers stood motionless, staring in amazement. as the big business man spoke, the little figure, which had evidently been watching them for some time, turned irresolutely as though about to run. then with gathering courage it began walking slowly towards them, holding out its arms with the palm up. "he's friendly," whispered the very young man; and they waited, silent, as the man approached. as he came closer, they could see he was hardly more than a boy, perhaps twenty years of age. his lean, gray body was nearly naked. around his waist he wore a drab-colored tunic, of a substance they could not identify. his feet and legs were bare. on his chest were strapped a thin stone plate, slightly convex. his thick, wavy, black hair, cut at the base of his neck, hung close about his ears. his head was uncovered. his features were regular and pleasing; his smile showed an even row of very white teeth. the three men did not speak or move until, in a moment, more, he stood directly before them, still holding out his hands palm up. then abruptly he spoke. "the master welcomes his friends," he said in a soft musical voice. he gave the words a most curious accent and inflexion, yet they were quite understandable to his listeners. "the master welcomes his friends," he repeated, dropping his arms to his sides and smiling in a most friendly manner. the very young man caught his breath. "he's been sent to meet us; he's from rogers. what do you think of that? we're all right now!" he exclaimed excitedly. the doctor held out his hand, and the oroid, hesitating a moment in doubt, finally reached up and grasped it. "are you from rogers?" asked the doctor. the oroid looked puzzled. then he turned and flung out his arm in a sweeping gesture towards the deeper woods before them. "rogers--master," he said. "you were waiting for us?" persisted the doctor; but the other only shook his head and smiled his lack of comprehension. "he only knows the first words he said," the big business man suggested. "he must be from rogers," the very young man put in. "see, he wants us to go with him." the oroid was motioning them forward, holding out his hand as though to lead them. the very young man started forward, but the big business man held him back. "wait a moment," he said. "i don't think we ought to go among these people as large as we are. rogers is evidently alive and waiting for us. why wouldn't it be better to be about his size, instead of ten-foot giants as we would look now?" "how do you know how big rogers is?" asked the very young man. "i think that a good idea," agreed the doctor. "rogers described these oroid men as being some six inches shorter than himself, on the average." "this one might be a pygmy, for all we know," said the very young man. "we might chance it that he's of normal size," said the doctor, smiling. "i think we should make ourselves smaller." the oroid stood patiently by and watched them with interested eyes as each took a tiny pellet from a vial under his arm and touched it to his tongue. when they began to decrease in size his eyes widened with fright and his legs shook under him. but he stood his ground, evidently assured by their smiles and friendly gestures. in a few minutes the action of the drug was over, and they found themselves not more than a head taller than the oroid. in this size he seemed to like them better, or at least he stood in far less awe of them, for now he seized them by the arms and pulled them forward vigorously. they laughingly yielded, and, led by this strange being of another world, they turned from the open places they had been following and plunged into the depths of the forest. chapter xviii the chemist and his son for an hour or more the three adventurers followed their strange guide in silence through the dense, trackless woods. he walked very rapidly, looking neither to the right nor to the left, finding his way apparently by an intuitive sense of direction. occasionally he glanced back over his shoulder and smiled. walking through the woods here was not difficult, and the party made rapid progress. the huge, upstanding tree-trunks were devoid of limbs for a hundred feet or more above the ground. on some of them a luxuriant vine was growing--a vine that bore a profusion of little gray berries. in the branches high overhead a few birds flew to and fro, calling out at times with a soft, cooing note. the ground--a gray, finely powdered sandy loam--was carpeted with bluish fallen leaves, sometimes with a species of blue moss, and occasional ferns of a like color. the forest was dense, deep, and silent; the tree branches overhead locked together in a solid canopy, shutting out the black sky above. yet even in this seclusion the scene remained as light as it had been outside the woods in the open. darkness indeed was impossible in this land; under all circumstances the light seemed the same--neither too bright nor too dim--a comfortable, steady glow, restful, almost hypnotic in its sameness. they had traveled perhaps six miles from the point where they met their oroid guide when suddenly the very young man became aware that other oroids were with them. looking to one side, he saw two more of these strange gray men, silently stalking along, keeping pace with them. turning, he made out still another, following a short distance behind. the very young man was startled, and hurriedly pointed them out to his companions. "wait," called the doctor to their youthful guide, and abruptly the party came to a halt. by these signs they made their guide understand that they wanted these other men to come closer. the oroid shouted to them in his own quaint tongue, words of a soft, liquid quality with a wistful sound--words wholly unintelligible to the adventurers. the men came forward diffidently, six of them, for three others appeared out of the shadows of the forest, and stood in a group, talking among themselves a little and smiling at their visitors. they were all dressed similarly to lao--for such was the young oroid's name--and all of them older than he, and of nearly the same height. "do any of you speak english?" asked the doctor, addressing them directly. evidently they did not, for they answered only by shaking their heads and by more smiles. then one of them spoke. "the master welcomes his friends," he said. and all the others repeated it after him, like children in school repeating proudly a lesson newly learned. the doctor and his two friends laughed heartily, and, completely reassured by this exhibition of their friendliness, they signified to lao that they were ready again to go forward. as they walked onward through the apparently endless and unchanging forest, surrounded by what the very young man called their "guard of honor," they were joined from time to time by other oroid men, all of whom seemed to know who they were and where they were going, and who fell silently into line with them. within an hour their party numbered twenty or more. seeing one of the natives stop a moment and snatch some berries from one of the vines with which many of the trees were encumbered, the very young man did the same. he found the berries sweet and palatable, and he ate a quantity. then discovering he was hungry, he took some crackers from his belt and ate them walking along. the doctor and the big business man ate also, for although they had not realized it, all three were actually famished. shortly after this the party came to a broad, smooth-flowing river, its banks lined with rushes, with here and there a little spot of gray, sandy beach. it was apparent from lao's signs that they must wait at this point for a boat to take them across. this they were glad enough to do, for all three had gone nearly to the limit of their strength. they drank deep of the pure river water, laved their aching limbs in it gratefully, and lay down, caring not a bit how long they were forced to wait. in perhaps another hour the boat appeared. it came from down the river, propelled close inshore by two members of their own party who had gone to fetch it. at first the travelers thought it a long, oblong raft. then as it came closer they could see it was constructed of three canoes, each about thirty feet long, hollowed out of tree-trunks. over these was laid a platform of small trees hewn roughly into boards. the boat was propelled by long, slender poles in the hands of the two men, who, one on each side, dug them into the bed of the river and walked with them the length of the platform. on to this boat the entire party crowded and they were soon well out on the shallow river, headed for its opposite bank. the very young man, seated at the front end of the platform with his legs dangling over and his feet only a few inches above the silver phosphorescence of the rippling water underneath, sighed luxuriously. "this beats anything we've done yet," he murmured. "gee, it's nice here!" when they landed on the farther bank another group of natives was waiting for them. the party, thus strengthened to nearly forty, started off immediately into the forest, which on this side of the river appeared equally dense and trackless. they appeared now to be paralleling the course of the river a few hundred yards back from its bank. after half an hour of this traveling they came abruptly to what at first appeared to be the mouth of a large cave, but which afterwards proved to be a tunnel-like passageway. into this opening the party unhesitatingly plunged. within this tunnel, which sloped downward at a considerable angle, they made even more rapid progress than in the forest above. the tunnel walls here were perhaps twenty feet apart--walls of a glistening, radiant, crystalline rock. the roof of the passageway was fully twice as high as its width; its rocky floor was smooth and even. after a time this tunnel was crossed by another somewhat broader and higher, but in general of similar aspect. it, too, sloped downward, more abruptly from the intersection. into this latter passageway the party turned, still taking the downward course. as they progressed, many other passageways were crossed, the intersections of which were wide at the open spaces. occasionally the travelers encountered other natives, all of them men, most of whom turned and followed them. the big business man, after over an hour of this rapid walking downward, was again near the limit of his endurance, when the party, after crossing a broad, open square, came upon a sort of sleigh, with two animals harnessed to it. it was standing at the intersection of a still broader, evidently more traveled passageway, and in it was an attendant, apparently fast asleep. into this sleigh climbed the three travelers with their guide lao; and, driven by the attendant, they started down the broader tunnel at a rapid pace. the sleigh was balanced upon a broad single runner of polished stone, with a narrow, slightly shorter outrider on each side; it slid smoothly and easily on this runner over the equally smooth, metallic rock of the ground. the reindeer-like animals were harnessed by their heads to a single shaft. they were guided by a short, pointed pole in the hands of the driver, who, as occasion demanded, dug it vigorously into their flanks. in this manner the travelers rode perhaps half an hour more. the passageway sloped steeply downward, and they made good speed. finally without warning, except by a sudden freshening of the air, they emerged into the open, and found themselves facing a broad, rolling stretch of country, dotted here and there with trees--the country of the oroids at last. for the first time since leaving their own world the adventurers found themselves amid surroundings that at least held some semblance of an aspect of familiarity. the scene they faced now might have been one of their own land viewed on an abnormally bright though moonless evening. for some miles they could see a rolling, open country, curving slightly upward into the dimness of the distance. at their right, close by, lay a broad lake, its surface wrinkled under a gentle breeze and gleaming bright as a great sheet of polished silver. overhead hung a gray-blue, cloudless sky, studded with a myriad of faint, twinkling, golden-silver stars. on the lake shore lay a collection of houses, close together, at the water's edge and spreading back thinly into the hills behind. this they knew to be arite--the city of their destination. at the end of the tunnel they left the sleigh, and, turning down the gentle sloping hillside, leisurely approached the city. they were part way across an open field separating them from the nearest houses, when they saw a group of figures coming across the field towards them. this group stopped when still a few hundred yards away, only two of the figures continuing to come forward. they came onward steadily, the tall figure of a man clothed in white, and by his side a slender, graceful boy. in a moment more lao, walking in front of the doctor and his two companions, stopped suddenly and, turning to face them, said quietly, "the master." the three travelers, with their hearts pounding, paused an instant. then with a shout the very young man dashed forward, followed by his two companions. "it's rogers--it's rogers!" he called; and in a moment more the three men were beside the chemist, shaking his hand and pouring at him excitedly their words of greeting. the chemist welcomed them heartily, but with a quiet, curious air of dignity that they did not remember he possessed before. he seemed to have aged considerably since they had last seen him. the lines in his face had deepened; the hair on his temples was white. he seemed also to be rather taller than they remembered him, and certainly he was stouter. he was dressed in a long, flowing robe of white cloth, gathered in at the waist by a girdle, from which hung a short sword, apparently of gold or of beaten brass. his legs were bare; on his feet he wore a form of sandal with leather thongs crossing his insteps. his hair grew long over his ears and was cut off at the shoulder line in the fashion of the natives. when the first words of greeting were over, the chemist turned to the boy, who was standing apart, watching them with big, interested eyes. "my friends," he said quietly, yet with a little underlying note of pride in his voice, "this is my son." the boy approached deferentially. he was apparently about ten or eleven years of age, tall as his father's shoulder nearly, extremely slight of build, yet with a body perfectly proportioned. he was dressed in a white robe similar to his father's, only shorter, ending at his knees. his skin was of a curious, smooth, milky whiteness, lacking the gray, harder look of that of the native men, and with just a touch of the iridescent quality possessed by the women. his features were cast in a delicate mold, pretty enough almost to be called girlish, yet with a firm squareness of chin distinctly masculine. his eyes were blue; his thick, wavy hair, falling to his shoulders, was a chestnut brown. his demeanor was graceful and dignified, yet with a touch of ingenuousness that marked him for the care-free child he really was. he held out his hands palms up as he approached. "my name is loto," he said in a sweet, soft voice, with perfect self-possession. "i'm glad to meet my father's friends." he spoke english with just a trace of the liquid quality that characterized his mother's tongue. "you are late getting here," remarked the chemist with a smile, as the three travelers, completely surprised by this sudden introduction, gravely shook hands with the boy. during this time the young oroid who had guided them down from the forest above the tunnels, had been standing respectfully behind them, a few feet away. a short distance farther on several small groups of natives were gathered, watching the strangers. with a few swift words loto now dismissed their guide, who bowed low with his hands to his forehead and left them. led by the chemist, they continued on down into the city, talking earnestly, telling him the details of their trip. the natives followed them as they moved forward, and as they entered the city others looked at them curiously and, the very young man thought, with a little hostility, yet always from a respectful distance. evidently it was night, or at least the time of sleep at this hour, for the streets they passed through were nearly deserted. chapter xix the city of arite the city of arite, as it looked to them now, was strange beyond anything they had ever seen, but still by no means as extraordinary as they had expected it would be. the streets through which they walked were broad and straight, and were crossed by others at regular intervals of two or three hundred feet. these streets paralleled each other with mathematical regularity. the city thus was laid out most orderly, but with one peculiarity; the streets did not run in two directions crossing each other at right angles, but in three, each inclined to an equal degree with the others. the blocks of houses between them, therefore, were cut into diamond-shaped sections and into triangles, never into squares or oblongs. most of the streets seemed paved with large, flat gray blocks of a substance resembling highly polished stone, or a form of opaque glass. there were no sidewalks, but close up before the more pretentious of the houses, were small trees growing. the houses themselves were generally triangular or diamond-shaped, following the slope of the streets. they were, most of them, but two stories in height, with flat roofs on some of which flowers and trellised vines were growing. they were built principally of the same smooth, gray blocks with which the streets were paved. their windows were large and numerous, without window-panes, but closed now, nearly all of them by shining, silvery curtains that looked as though they might have been woven from the metal itself. the doors were of heavy metal, suggesting brass or gold. on some of the houses tiny low-railed balconies hung from the upper windows out over the street. the party proceeded quietly through this now deserted city, crossing a large tree-lined square, or park, that by the confluence of many streets seemed to mark its center, and turned finally into another diagonal street that dropped swiftly down towards the lake front. at the edge of a promontory this street abruptly terminated in a broad flight of steps leading down to a little beach on the lake shore perhaps a hundred feet below. the chemist turned sharp to the right at the head of these steps, and, passing through the opened gateway of an arch in a low gray wall, led his friends into a garden in which were growing a profusion of flowers. these flowers, they noticed, were most of them blue or gray, or of a pale silvery whiteness, lending to the scene a peculiarly wan, wistful appearance, yet one of extraordinary, quite unearthly beauty. through the garden a little gray-pebbled path wound back to where a house stood, nearly hidden in a grove of trees, upon a bluff directly overlooking the lake. "my home, gentlemen," said the chemist, with a wave of his hand. as they approached the house they heard, coming from within, the mellow voice of a woman singing--an odd little minor theme, with a quaint, lilting rhythm, and words they could not distinguish. accompanying the voice were the delicate tones of some stringed instrument suggesting a harp. "we are expected," remarked the chemist with a smile. "lylda is still up, waiting for us." the very young man's heart gave a leap at the mention of the name. from the outside, the chemist's house resembled many of the larger ones they had seen as they came through the city. it was considerably more pretentious than any they had yet noticed, diamond-shaped--that is to say, a flattened oblong--two stories in height and built of large blocks of the gray polished stone. unlike the other houses, its sides were not bare, but were partly covered by a luxuriant growth of vines and trellised flowers. there were no balconies under its windows, except on the lake side. there, at the height of the second story, a covered balcony broad enough almost to be called a veranda, stretched the full width of the house. a broad door of brass, fronting the garden, stood partly open, and the chemist pushed it wide and ushered in his friends. they found themselves now in a triangular hallway, or lobby, with an open arch in both its other sides giving passage into rooms beyond. through one of these archways the chemist led them, into what evidently was the main living-room of the dwelling. it was a high-ceilinged room nearly triangular in shape, thirty feet possibly at its greatest width. in one wall were set several silvery-curtained windows, opening out on to the lake. on the other side was a broad fireplace and hearth with another archway beside it leading farther into the house. the walls of the room were lined with small gray tiles; the floor also was tiled with gray and white, set in design. on the floor were spread several large rugs, apparently made of grass or fibre. the walls were bare, except between the windows, where two long, narrow, heavily embroidered strips of golden cloth were hanging. in the center of the room stood a circular stone table, its top a highly polished black slab of stone. this table was set now for a meal, with golden metal dishes, huge metal goblets of a like color, and beautifully wrought table utensils, also of gold. around the table were several small chairs, made of wicker. in the seat of each lay a padded fiber cushion, and over the back was hung a small piece of embroidered cloth. with the exception of these chairs and table, the room was practically devoid of furniture. against one wall was a smaller table of stone, with a few miscellaneous objects on its top, and under each window stood a small white stone bench. a fire glowed in the fireplace grate--a fire that burned without flame. on the hearth before it, reclining on large silvery cushions, was a woman holding in her hands a small stringed instrument like a tiny harp or lyre. when the men entered the room she laid her instrument aside and rose to her feet. as she stood there for an instant, expectant, with the light of welcome in her eyes, the three strangers beheld what to them seemed the most perfect vision of feminine loveliness they had ever seen. the woman's age was at first glance indeterminate. by her face, her long, slender, yet well-rounded neck, and the slim curves of her girlish figure, she might have been hardly more than twenty. yet in her bearing there was that indefinable poise and dignity that bespoke the more mature, older woman. she was about five feet tall, with a slender, almost fragile, yet perfectly rounded body. her dress consisted of a single flowing garment of light-blue silk, reaching from the shoulders to just above her knees. it was girdled at the waist by a thick golden cord that hung with golden tasseled pendants at her side. a narrower golden cord crossed her breast and shoulders. her arms, legs, and shoulders were bare. her skin was smooth as satin, milky white, and suffused with the delicate tints of many colors. her hair was thick and very black; it was twisted into two tresses that fell forward over each shoulder nearly to her waist and ended with a little silver ribbon and tassel tied near the bottom. her face was a delicate oval. her lips were full and of a color for which in english there is no name. it would have been red doubtless by sunlight in the world above, but here in this silver light of phosphorescence, the color red, as we see it, was impossible. her nose was small, of grecian type. her slate-gray eyes were rather large, very slightly upturned at the corners, giving just a touch of the look of our women of the orient. her lashes were long and very black. in conversation she lowered them at times with a charming combination of feminine humility and a touch of coquetry. her gaze from under them had often a peculiar look of melting softness, yet always it was direct and honest. such was the woman who quietly stood beside her hearth, waiting to welcome these strange guests from another world. as the men entered through the archway, the boy loto pushed quickly past them in his eagerness to get ahead, and, rushing across the room, threw himself into the woman's arms crying happily, "_mita, mita._" the woman kissed him affectionately. then, before she had time to speak, the boy pulled her forward, holding her tightly by one hand. "this is my mother," he said with a pretty little gesture. "her name is lylda." the woman loosened herself from his grasp with a smile of amusement, and, native fashion, bowed low with her hands to her forehead. "my husband's friends are welcome," she said simply. her voice was soft and musical. she spoke english perfectly, with an intonation of which the most cultured woman might be proud, but with a foreign accent much more noticeable than that of her son. "a very long time we have been waiting for you," she added; and then, as an afterthought, she impulsively offered them her hand in their own manner. the chemist kissed his wife quietly. in spite of the presence of strangers, for a moment she dropped her reserve, her arms went up around his neck, and she clung to him an instant. gently putting her down, the chemist turned to his friends. "i think lylda has supper waiting," he said. then as he looked at their torn, woolen suits that once were white, and the ragged shoes upon their feet, he added with a smile, "but i think i can make you much more comfortable first." he led them up a broad, curving flight of stone steps to a room above, where they found a shallow pool of water, sunk below the level of the floor. here he left them to bathe, getting them meanwhile robes similar to his own, with which to replace their own soiled garments. in a little while, much refreshed, they descended to the room below, where lylda had supper ready upon the table waiting for them. "only a little while ago my father and aura left," said lylda, as they sat down to eat. "lylda's younger sister," the chemist explained. "she lives with her father here in arite." the very young man parted his lips to speak. then, with heightened color in his cheeks, he closed them again. they were deftly served at supper by a little native girl who was dressed in a short tunic reaching from waist to knees, with circular discs of gold covering her breasts. there was cooked meat for the meal, a white starchy form of vegetable somewhat resembling a potato, a number of delicious fruits of unfamiliar variety, and for drink the juice of a fruit that tasted more like cider than anything they could name. at the table loto perched himself beside the very young man, for whom he seemed to have taken a sudden fancy. "i like you," he said suddenly, during a lull in the talk. "i like you, too," answered the very young man. "aura is very beautiful; you'll like her." "i'm sure i will," the very young man agreed soberly. "what's your name?" persisted the boy. "my name's jack. and i'm glad you like me. i think we're friends, don't you?" and so they became firm friends, and, as far as circumstances would permit, inseparable companions. lylda presided over the supper with the charming grace of a competent hostess. she spoke seldom, yet when the conversation turned to the great world above in which her husband was born, she questioned intelligently and with eager interest. evidently she had a considerable knowledge of the subject, but with an almost childish insatiable curiosity she sought from her guests more intimate details of the world they lived in. when in lighter vein their talk ran into comments upon the social life of their own world, lylda's ready wit, combined with her ingenuous simplicity, put to them many questions which made the giving of an understandable answer sometimes amusingly difficult. when the meal was over the three travelers found themselves very sleepy, and all of them were glad when the chemist suggested that they retire almost immediately. he led them again to the upper story into the bedroom they were to occupy. there, on the low bedsteads, soft with many quilted coverings, they passed the remainder of the time of sleep in dreamless slumber, utterly worn out by their journey, nor guessing what the morning would bring forth. chapter xx the world of the ring next morning after breakfast the four men sat upon the balcony overlooking the lake, and prepared to hear the chemist's narrative of what had happened since he left them five years before. they had already told him of events in their world, the making of the chemicals and their journey down into the ring, and now they were ready to hear his story. at their ease here upon the balcony, reclining in long wicker chairs of the chemist's own design, as he proudly admitted, they felt at peace with themselves and the world. below them lay the shining lake, above spread a clear, star-studded sky. against their faces blew the cool breath of a gentle summer's breeze. as they sat silent for a moment, enjoying almost with awe the beauties of the scene, and listening to the soft voice of lylda singing to herself in the garden, the very young man suddenly thought of the one thing lacking to make his enjoyment perfect. "i wish i had a cigarette," he remarked wistfully. the chemist with a smile produced cigars of a leaf that proved a very good substitute for tobacco. they lighted them with a tiny metal lighter of the flint-and-steel variety, filled with a fluffy inflammable wick--a contrivance of the chemist's own making--and then he started his narrative. "there is much to tell you, my friends," he began thoughtfully. "much that will interest you, shall we say from a socialistic standpoint? i shall make it brief, for we have no time to sit idly talking. "i must tell you now, gentlemen, of what i think you have so far not even had a hint. you have found me living here," he hesitated and smiled, "well at least under pleasant and happy circumstances. yet as a matter of fact, your coming was of vital importance, not only to me and my family, but probably to the future welfare of the entire oroid nation. "we are approaching a crisis here with which i must confess i have felt myself unable to cope. with your help, more especially with the power of the chemicals you have brought with you, it may be possible for us to deal successfully with the conditions facing us." "what are they?" asked the very young man eagerly. "perhaps it would be better for me to tell you chronologically the events as they have occurred. as you remember when i left you twelve years ago----" "five years," interrupted the very young man. "five or twelve, as you please," said the chemist smiling. "it was my intention then, as you know, to come back to you after a comparatively short stay here." "and bring mrs.--er--lylda, with you," put in the very young man, hesitating in confusion over the christian name. "and bring lylda with me," finished the chemist. "i got back here without much difficulty, and in a very much shorter time and with less effort than on my first trip. i tried an entirely different method; i stayed as large as possible while descending, and diminished my size materially only after i had reached the bottom." "i told you----" said the big business man. "it was a dangerous method of procedure, but i made it successfully without mishap. "lylda and i were married in native fashion shortly after i reached arite." "how was that; what fashion?" the very young man wanted to know, but the chemist went on. "it was my intention to stay here only a few weeks and then return with lylda. she was willing to follow me anywhere i might take her, because--well, perhaps you would hardly understand, but--women here are different in many ways than you know them. "i stayed several months, still planning to leave almost at any time. i found this world an intensely interesting study. then, when--loto was expected, i again postponed my departure. "i had been here over a year before i finally gave up my intention of ever returning to you. i have no close relatives above, you know, no one who cares much for me or for whom i care, and my life seemed thoroughly established here. "i am afraid gentlemen, i am offering excuses for myself--for my desertion of my own country in its time of need. i have no defense. as events turned out i could not have helped probably, very much, but still--that is no excuse. i can only say that your world up there seemed so very--very--far away. events up there had become to me only vague memories as of a dream. and lylda and my little son were so near, so real and vital to me. well, at any rate i stayed, deciding definitely to make my home and to end my days here." "what did you do about the drugs?" asked the doctor. "i kept them hidden carefully for nearly a year," the chemist replied. "then fearing lest they should in some way get loose, i destroyed them. they possess a diabolical power, gentlemen; i am afraid of it." "they called you the master," suggested the very young man, after a pause. "why was that?" the chemist smiled. "they do call me the master. that has been for several years. i suppose i am the most important individual in the nation to-day." "i should think you would be," said the very young man quickly. "what you did, and with the knowledge you have." the chemist went on. "lylda and i lived with her father and aura--her mother is dead you know--until after loto was born. then we had a house further up in the city. later, about eight years ago, i built this house we now occupy and lylda laid out its garden which she is tremendously proud of, and which i think is the finest in arite. "because of what i had done in the malite war, i became naturally the king's adviser. every one felt me the savior of the nation, which, in a way, i suppose i was. i never used the drugs again and, as only a very few of the people ever understood them, or in fact ever knew of them or believed in their existence, my extraordinary change in stature was ascribed to some supernatural power. i have always since been credited with being able to exert that power at will, although i never used it but that once." "you have it again now," said the doctor smiling. "yes, i have, thank god," answered the chemist fervently, "though i hope i never shall have to use it." "aren't you planning to go back with us," asked the very young man, "even for a visit?" the chemist shook his head. "my way lies here," he said quietly, yet with deep feeling. a silence followed; finally the chemist roused himself from his reverie, and went on. "although i never again changed my stature, there were a thousand different ways in which i continued to make myself--well, famous throughout the land. i have taught these people many things, gentlemen--like this for instance." he indicated his cigar, and the chair in which he was sitting. "you cannot imagine what a variety of things one knows beyond the knowledge of so primitive a race as this. "and so gradually, i became known as the master. i have no official position, but everywhere i am known by that name. as a matter of fact, for the past year at least, it has been rather too descriptive a title----" the chemist smiled somewhat ruefully--"for i have had in reality, and have now, the destiny of the country on my shoulders." "you're not threatened with another war?" asked the very young man. "no, not exactly that. but i had better go on with my story first. this is a very different world now, gentlemen, from that i first entered twelve years ago. i think first i should tell you about it as it was then." his three friends nodded their agreement and the chemist continued. "i must make it clear to you gentlemen, the one great fundamental difference between this world and yours. in the evolution of this race there has been no cause for strife--the survival of the fittest always has been an unknown doctrine--a non-existent problem. "in extent this inner surface upon which we are now living is nearly as great as the surface of your own earth. from the earliest known times it has been endowed with a perfect climate--a climate such as you are now enjoying." the very young man expanded his chest and looked his appreciation. "the climate, the rainfall, everything is ideal for crops and for living conditions. in the matter of food, one needs in fact do practically nothing. fruits of a variety ample to sustain life, grow wild in abundance. vegetables planted are harvested seemingly without blight or hazard of any kind. no destructive insects have ever impeded agriculture; no wild animals have ever existed to harass humanity. nature in fact, offers every help and no obstacle towards making a simple, primitive life easy to live. "under such conditions the race developed only so far as was necessary to ensure a healthful pleasant existence. civilization here is what you would call primitive: wants are few and easily supplied--too easily, probably, for without strife these people have become--well shall i say effeminate? they are not exactly that--it is not a good word." "i should think that such an unchanging, unrigorous climate would make a race deteriorate in physique rapidly," observed the doctor. "how about disease down here?" asked the big business man. "it is a curious thing," replied the chemist. "cleanliness seems to be a trait inborn with every individual in this race. it is more than godliness; it is the one great cardinal virtue. you must have noticed it, just in coming through arite. personal cleanliness of the people, and cleanliness of houses, streets--of everything. it is truly extraordinary to what extent they go to make everything inordinately, immaculately clean. possibly for that reason, and because there seems never to have been any serious disease germs existing here, sickness as you know it, does not exist." "guess you better not go into business here," said the very young man with a grin at the doctor. "there is practically no illness worthy of the name," went on the chemist. "the people live out their lives and, barring accident, die peacefully of old age." "how old do they live to be?" asked the big business man. "about the same as with you," answered the chemist. "only of course as we measure time." "say how about that?" the very young man asked. "my watch is still going--is it ticking out the old time or the new time down here?" "i should say probably--certainly--it was giving time of your own world, just as it always did," the chemist replied. "well, there's no way of telling, is there?" said the big business man. "what is the exact difference in time?" the doctor asked. "that is something i have had no means of determining. it was rather a curious thing; when i left that letter for you," the chemist turned to the doctor--"it never occurred to me that although i had told you to start down here on a certain day, i would be quite at a loss to calculate when that day had arrived. it was my estimation after my first trip here that time in this world passed at a rate about two and two-fifth times faster than it does in your world. that is as near as i ever came to it. we can calculate it more closely now, since we have only the interval of your journey down as an indeterminate quantity." "how near right did you hit it? when did you expect us?" asked the doctor. "about thirty days ago; i have been waiting since then. i sent nearly a hundred men through the tunnels into the forest to guide you in." "you taught them pretty good english," said the very young man. "they were tickled to death that they knew it, too," he added with a reminiscent grin. "you say about thirty days; how do you measure time down here?" asked the big business man. "i call a day, one complete cycle of sleeping and eating," the chemist replied. "i suppose that is the best translation of the oroid word; we have a word that means about the same thing." "how long is a day?" inquired the very young man. "it seems in the living about the same as your twenty-four hours; it occupies probably about the interval of time of ten hours in your world. "you see," the chemist went on, "we ordinarily eat twice between each time of sleep--once after rising--and once a few hours before bedtime. workers at severe muscular labor sometimes eat a light meal in between, but the custom is not general. time is generally spoken of as so many meals, rather than days." "but what is the arbitrary standard?" asked the doctor. "do you have an equivalent for weeks, or months or years?" "yes," answered the chemist, "based on astronomy the same as in your world. but i would rather not explain that now. i want to take you, later to-day, to see lylda's father. you will like him. he is--well, what we might call a scientist. he talks english fairly well. we can discuss astronomy with him; you will find him very interesting." "how can you tell time?" the very young man wanted to know. "there is no sun to go by. you have no clocks, have you?" "there is one downstairs," answered the chemist, "but you didn't notice it. lylda's father has a very fine one; he will show it to you." "it seems to me," began the doctor thoughtfully after a pause, reverting to their previous topic, "that without sickness, under such ideal living conditions as you say exist here, in a very short time this world would be over-populated." "nature seems to have taken care of that," the chemist answered, "and as a matter of fact quite the reverse is true. women mature in life at an age you would call about sixteen. but early marriages are not the rule; seldom is a woman married before she is twenty--frequently she is much older. her period of child-bearing, too, is comparatively short--frequently less than ten years. the result is few children, whose rate of mortality is exceedingly slow." "how about the marriages?" the very young man suggested. "you were going to tell us." "marriages are by mutual consent," answered the chemist, "solemnized by a simple, social ceremony. they are for a stated period of time, and are renewed later if both parties desire. when a marriage is dissolved children are cared for by the mother generally, and her maintenance if necessary is provided for by the government. the state becomes the guardian also of all illegitimate children and children of unknown parentage. but of both these latter classes there are very few. they work for the government, as do many other people, until they are of age, when they become free to act as they please." "you spoke about women being different than we knew them; how are they different?" the very young man asked. "if they're all like lylda i think they're great," he added enthusiastically, flushing a little at his own temerity. the chemist smiled his acknowledgment of the compliment. "the status of women--and their character--is i think one of the most remarkable things about this race. you will remember, when i returned from here the first time, that i was much impressed by the kindliness of these people. because of their history and their government they seem to have become imbued with the milk of human kindness to a degree approaching the utopian. "crime here is practically non-existent; there is nothing over which contention can arise. what crimes are committed are punished with a severity seemingly out of all proportion to what you would call justice. a persistent offender even of fairly trivial wrongdoing is put to death without compunction. there is no imprisonment, except for those awaiting trial. punishment is a reprimand with the threat of death if the offense is committed again, or death itself immediately. probably this very severity and the swiftness with which punishment is meted out, to a large extent discourages wrongdoing. but, fundamentally, the capacity for doing wrong is lacking in these people. "i have said practically nothing exists over which contention can arise. that is not strictly true. no race of people can develop without some individual contention over the possession of their women. the passions of love, hate and jealousy, centering around sex and its problems, are as necessarily present in human beings as life itself. "love here is deep, strong and generally lasting; it lacks fire, intensity--perhaps. i should say it is rather of a placid quality. hatred seldom exists; jealousy is rare, because both sexes, in their actions towards the other, are guided by a spirit of honesty and fairness that is really extraordinary. this is true particularly of the women; they are absolutely honest--square, through and through. "crimes against women are few, yet in general they are the most prevalent type we have. they are punishable by death--even those that you would characterize as comparatively slight offenses. it is significant too, that, in judging these crimes, but little evidence is required. a slight chain of proven circumstances and the word of the woman is all that is required. "this you will say, places a tremendous power in the hands of women. it does; yet they realize it thoroughly, and justify it. although they know that almost at their word a man will be put to death, practically never, i am convinced, is this power abused. with extreme infrequency, a female is proven guilty of lying. the penalty is death, for there is no place here for such a woman! "the result is that women are accorded a freedom of movement far beyond anything possible in your world. they are safe from harm. their morals are, according to the standard here, practically one hundred per cent perfect. with short-term marriages, dissolvable at will, there is no reason why they should be otherwise. curiously enough too, marriages are renewed frequently--more than that, i should say, generally--for life-long periods. polygamy with the consent of all parties is permitted, but seldom practiced. polyandry is unlawful, and but few cases of it ever appear. "you may think all this a curious system, gentlemen, but it works." "that's the answer," muttered the very young man. it was obvious he was still thinking of lylda and her sister and with a heightened admiration and respect. chapter xxi a life worth living the appearance of lylda at one of the long windows of the balcony, interrupted the men for a moment. she was dressed in a tunic of silver, of curious texture, like flexible woven metal, reaching to her knees. on her feet were little fiber sandals. her hair was twisted in coils, piled upon her head, with a knot low at the back of the neck. from her head in graceful folds hung a thin scarf of gold. she stood waiting in the window a moment for them to notice her; then she said quietly, "i am going for a time to the court." she hesitated an instant over the words. the chemist inclined his head in agreement, and with a smile at her guests, and a little bow, she withdrew. the visitors looked inquiringly at their host. "i must tell you about our government," said the chemist. "lylda plays quite an important part in it." he smiled at their obvious surprise. "the head of the government is the king. in reality he is more like the president of a republic; he is chosen by the people to serve for a period of about twenty years. the present king is now in--well let us say about the fifteenth year of his service. this translation of time periods into english is confusing," he interjected somewhat apologetically. "we shall see the king to-morrow; you will find him a most intelligent, likeable man. "as a sort of congress, the king has one hundred and fifty advisers, half of them women, who meet about once a month. lylda is one of these women. he also has an inner circle of closer, more intimate counselors consisting of four men and four women. one of these women is the queen; another is lylda. i am one of the men. "the capital of the nation is arite. each of the other cities governs itself in so far as its own local problems are concerned according to a somewhat similar system, but all are under the central control of the arite government." "how about the country in between, the--the rural population?" asked the big business man. "it is all apportioned off to the nearest city," answered the chemist. "each city controls a certain amount of the land around it. "this congress of one hundred and fifty is the law-making body. the judiciary is composed of one court in each city. there is a leader of the court, or judge, and a jury of forty--twenty men and twenty women. the juries are chosen for continuous service for a period of five years. lylda is at present serving in the arite court. they meet very infrequently and irregularly, called as occasion demands. a two-thirds vote is necessary for a decision; there is no appeal." "are there any lawyers?" asked the big business man. "there is no one who makes that his profession, no. generally the accused talks for himself or has some relative, or possibly some friend to plead his case." "you have police?" the doctor asked. "a very efficient police force, both for the cities and in the country. really they are more like detectives than police; they are the men i sent up into the forest to meet you. we also have an army, which at present consists almost entirely of this same police force. after the malite war it was of course very much larger, but of late years it has been disbanded almost completely. "how about money?" the very young man wanted to know. "there is none!" answered the chemist with a smile. "great scott, how can you manage that?" ejaculated the big business man. "our industrial system undoubtedly is peculiar," the chemist replied, "but i can only say again, it works. we have no money, and, so far, none apparently is needed. everything is bought and sold as an exchange. for instance, suppose i wish to make a living as a farmer. i have my land----" "how did you get it?" interrupted the very young man quickly. "all the land is divided up _pro rata_ and given by each city to its citizens. at the death of its owner it reverts to the government, and each citizen coming of age receives his share from the surplus always remaining." "what about women? can they own land too?" asked the very young man. "they have identical rights with men in everything," the chemist answered. "but women surely cannot cultivate their own land?" the doctor said. evidently he was thinking of lylda's fragile little body, and certainly if most of the oroid women were like her, labour in the fields would be for them quite impossible. "a few women, by choice, do some of the lighter forms of manual labor--but they are very few. nearly every woman marries within a few years after she receives her land; if it is to be cultivated, her husband then takes charge of it." "is the cultivation of land compulsory?" asked the big business man. "only when in a city's district a shortage of food is threatened. then the government decides the amount and kind of food needed, and the citizens, drawn by lot, are ordered to produce it. the government watches very carefully its food supply. in the case of overproduction, certain citizens, those less skillful, are ordered to work at something else. "this supervision over supply and demand is exercised by the government not only in the question of food but in manufactures, in fact, in all industrial activities. a very nice balance is obtained, so that practically no unnecessary work is done throughout the nation. "and gentlemen, do you know, as a matter of fact, i think that is the secret of a race of people being able to live without having to work most of its waking hours? if your civilization could eliminate all its unnecessary work, there would be far less work to do." "i wonder--isn't this balance of supply and demand very difficult to maintain?" asked the big business man thoughtfully. "not nearly so difficult as you would think," the chemist answered. "in the case of land cultivation, the government has a large reserve, the cultivation of which it adjusts to maintain this balance. thus, in some districts, the citizens do as they please and are never interfered with. "the same is true of manufactures. there is no organized business in the nation--not even so much as the smallest factory--except that conducted by the government. each city has its own factories, whose production is carefully planned exactly to equal the demand." "suppose a woman marries and her land is far away from her husband's? that would be sort of awkward, wouldn't it?" suggested the very young man. "each year at a stated time," the chemist answered, "transfers of land are made. there are generally enough people who want to move to make satisfactory changes of location practical. and then of course, the government always stands ready to take up any two widely separate pieces of land, and give others in exchange out of its reserve." "suppose you don't like the new land as well?" objected the very young man. "almost all land is of equal value," answered the chemist. "and of course, its state of cultivation is always considered." "you were speaking about not having money," prompted the very young man. "the idea is simply this: suppose i wish to cultivate nothing except, let us say, certain vegetables. i register with the government my intention and the extent to which i propose to go. i receive the government's consent. i then take my crops as i harvest them and exchange them for every other article i need." "with whom do you exchange them?" asked the doctor. "any one i please--or with the government. ninety per cent of everything produced is turned in to the government and other articles are taken from its stores." "how is the rate of exchange established?" asked the big business man. "it is computed by the government. private exchanges are supposed to be made at the same rate. it is against the law to cut under the government rate. but it is done, although apparently not with sufficient frequency to cause any trouble." "i should think it would be tremendously complicated and annoying to make all these exchanges," observed the big business man. "not at all," answered the chemist, "because of the governmental system of credits. the financial standing of every individual is carefully kept on record." "without any money? i don't get you," said the very young man with a frown of bewilderment. the chemist smiled. "well, i don't blame you for that. but i think i can make myself clear. let us take the case of loto, for instance, as an individual. when he comes of age he will be allotted his section of land. we will assume him to be without family at that time, entirely dependent on his own resources." "would he never have worked before coming of age?" the very young man asked. "children with parents generally devote their entire minority to getting an education, and to building their bodies properly. without parents, they are supported by the government and live in public homes. such children, during their adolescence, work for the government a small portion of their time. "now when loto comes of age and gets his land, located approximately where he desires it, he will make his choice as to his vocation. suppose he wishes not to cultivate his land but to work for the government. he is given some congenial, suitable employment at which he works approximately five hours a day. no matter what he elects to do at the time he comes of age the government opens an account with him. he is credited with a certain standard unit for his work, which he takes from the government in supplies at his own convenience." "what is the unit?" asked the big business man. "it is the average work produced by the average worker in one day--purely an arbitrary figure." "like our word horse-power?" put in the doctor. "exactly. and all merchandise, food and labor is valued in terms of it. "thus you see, every individual has his financial standing--all in relation to the government. he can let his balance pile up if he is able, or he can keep it low." "suppose he goes into debt?" suggested the very young man. "in the case of obvious, verified necessity, the government will allow him a limited credit. persistent--shall i say willful--debt is a crime." "i thought at first," said the big business man, "that everybody in this nation was on the same financial footing--that there was no premium put upon skill or industriousness. now i see that one can accumulate, if not money, at least an inordinate amount of the world's goods." "not such an inordinate amount," said the chemist smiling. "because there is no inheritance. a man and woman, combining their worldly wealth, may by industry acquire more than others, but they are welcome to enjoy it. and they cannot, in one lifetime, get such a preponderance of wealth as to cause much envy from those lacking it." "what happens to this house when you and lylda die, if loto cannot have it?" the big business man asked. "it is kept in repair by the government and held until some one with a sufficiently large balance wants to buy it." "are all workers paid at the same rate?" asked the doctor. "no, but their wages are much nearer equal than in your world." "you have to hire people to work for you, how do you pay them?" the doctor inquired. "the rate is determined by governmental standard. i pay them by having the amount deducted from my balance and added to theirs." "when you built this house, how did you go about doing it?" asked the big business man. "i simply went to the government, and they built it for me according to my own ideas and wishes, deducting its cost from my balance." "what about the public work to be done?" asked the big business man. "caring for the city streets, the making of roads and all that. do you have taxes?" "no," answered the chemist smiling, "we do not have taxes. quite the reverse, we sometimes have dividends. "the government, you must understand, not only conducts a business account with each of its citizens, but one with itself also. the value of articles produced is computed with a profit allowance, so that by a successful business administration, the government is enabled not only to meet its public obligations, but to acquire a surplus to its own credit in the form of accumulated merchandise. this surplus is divided among the people every five years--a sort of dividend." "i should think some cities might have much more than others," said the big business man. "that would cause discontent, wouldn't it?" "it would probably cause a rush of people to the more successful cities. but it doesn't happen, because each city reports to the national government and the whole thing is averaged up. you see it is all quite simple," the chemist finished. "and it makes life here very easy to live, and very worth the living." unnoticed by the four interested men, a small compact-looking gray cloud had come sweeping down from the horizon above the lake and was scudding across the sky toward arite. a sudden sharp crack of thunder interrupted their conversation. "hello, a storm!" exclaimed the chemist, looking out over the lake. "you've never seen one, have you? come upstairs." they followed him into the house and upstairs to its flat roof. from this point of vantage they saw that the house was built with an interior courtyard or _patio_. looking down into this courtyard from the roof they could see a little, splashing fountain in its center, with flower beds, a narrow gray path, and several small white benches. the roof, which was guarded with a breast-high parapet around both its inner and outer edges, was beautifully laid out with a variety of flowers and with trellised flower-bearing vines. in one corner were growing a number of small trees with great fan-shaped leaves of blue and bearing a large bell-shaped silver blossom. one end of the roof on the lake side was partially enclosed. towards this roofed enclosure the chemist led his friends. within it a large fiber hammock hung between two stone posts. at one side a depression in the floor perhaps eight feet square was filled with what might have been blue pine needles, and a fluffy bluish moss. this rustic couch was covered at one end by a canopy of vines bearing a little white flower. as they entered the enclosure, it began to rain, and the chemist slid forward several panels, closing them in completely. there were shuttered windows in these walls, through which they could look at the scene outside--a scene that with the coming storm was weird and beautiful beyond anything they had ever beheld. the cloud had spread sufficiently now to blot out the stars from nearly half of the sky. it was a thick cloud, absolutely opaque, and yet it caused no appreciable darkness, for the starlight it cut off was negligible and the silver radiation from the lake had more than doubled in intensity. under the strong wind that had sprung up the lake assumed now an extraordinary aspect. its surface was raised into long, sweeping waves that curved sharply and broke upon themselves. in their tops the silver phosphorescence glowed and whirled until the whole surface of the lake seemed filled with a dancing white fire, twisting, turning and seeming to leap out of the water high into the air. several small sailboats, square, flat little catamarans, they looked, showed black against the water as they scudded for shore, trailing lines of silver out behind them. the wind increased in force. below, on the beach, a huge rock lay in the water, against which the surf was breaking. columns of water at times shot into the air before the face of the rock, and were blown away by the wind in great clouds of glistening silver. occasionally it thundered with a very sharp intense crack accompanied by a jagged bolt of bluish lightning that zigzagged down from the low-hanging cloud. then came the rain in earnest, a solid, heavy torrent, that bent down the wind and smoothed the surface of the lake. the rain fell almost vertically, as though it were a tremendous curtain of silver strings. and each of these strings broke apart into great shining pearls as the eye followed downward the course of the raindrops. for perhaps ten minutes the silver torrent poured down. then suddenly it ceased. the wind had died away; in the air there was the fresh warm smell of wet and steaming earth. from the lake rolled up a shimmering translucent cloud of mist, like an enormous silver fire mounting into the sky. and then, as the gray cloud swept back behind them, beyond the city, and the stars gleamed overhead, they saw again that great trail of star-dust which the chemist first had seen through his microscope, hanging in an ever broadening arc across the sky, and ending vaguely at their feet. chapter xxii the trial in a few moments more the storm had passed completely; only the wet city streets, the mist over the lake, and the moist warmth of the air remained. for some time the three visitors to this extraordinary world stood silent at the latticed windows, awed by what they had seen. the noise of the panels as the chemist slid them back brought them to themselves. "a curious land, gentlemen," he remarked quietly. "it's--it's weird," the very young man ejaculated. the chemist led them out across the roof to its other side facing the city. the street upon which the house stood sloped upwards over the hill behind. it was wet with the rain and gleamed like a sheet of burnished silver. and down its sides now ran two little streams of liquid silver fire. the street, deserted during the storm, was beginning to fill again with people returning to their tasks. at the intersection with the next road above, they could see a line of sleighs passing. beneath them, before the wall of the garden a little group of men stood talking; on a roof-top nearby a woman appeared with a tiny naked infant which she sat down to nurse in a corner of her garden. "a city at work," said the chemist with a wave of his hand. "shall we go down and see it?" his three friends assented readily, the very young man suggesting promptly that they first visit lylda's father and aura. "he is teaching loto this morning," said the chemist smiling. "why not go to the court?" suggested the big business man. "is the public admitted?" asked the doctor. "nothing is secret here," the chemist answered. "by all means, we will go to the court first, if you wish; lylda should be through very shortly." the court of arite stood about a mile away near the lake shore. as they left the house and passed through the city streets the respect accorded the chemist became increasingly apparent. the three strangers with him attracted considerable attention, for, although they wore the conventional robes in which the more prominent citizens were generally attired, their short hair and the pallid whiteness of their skins made them objects of curiosity. no crowd gathered; those they passed stared a little, raised their hands to their foreheads and went their way, yet underneath these signs of respect there was with some an air of sullenness, of hostility, that the visitors could not fail to notice. the oroid men, in street garb, were dressed generally in a short metallic-looking tunic of drab, with a brighter-colored girdle. the women, most of them, wore only a sort of skirt, reaching from waist to knees; a few had circular discs covering their breasts. there were hardly any children to be seen, except occasionally a little face staring at them from a window, or peering down from a roof-top. once or twice they passed a woman with an infant slung across her back in a sort of hammock. the most common vehicle was the curious form of sleigh in which they had ridden down through the tunnels. they saw also a few little two-wheeled carts, with wheels that appeared to be a solid segment of tree-trunk. all the vehicles were drawn by meek-looking little gray animals like a small deer without horns. the court-house of arite, though a larger building, from the outside was hardly different than most others in the city. it was distinct, however, in having on either side of the broad doorway that served as its main entrance, a large square stone column. as they entered, passing a guard who saluted them respectfully, the visitors turned from a hallway and ascended a flight of steps. at the top they found themselves on a balcony overlooking the one large room that occupied almost the entire building. the balcony ran around all three sides (the room was triangular in shape) and was railed with a low stone parapet. on it were perhaps fifty people, sitting quietly on stone benches that lay close up behind the parapet. an attendant stood at each of the corners of the balcony; the one nearest bowed low as the chemist and his companions entered silently and took their seats. from the balcony the entire room below was in plain view. at the apex of its triangle sat the judge, on a raised dais of white stone with a golden canopy over it. he was a man about fifty--this leader of the court--garbed in a long loose robe of white. his hair, that fell on his shoulders, was snowy white, and around his forehead was a narrow white band. he held in his hand a sort of scepter of gold with a heavy golden triangle at its end. in six raised tiers of unequal length, like a triangular flight of stairs across the angle of the room, and directly in front of the judge, was the jury--twenty men and twenty women, seated in alternate rows. the men wore loose robes of gray; the women robes of blue. on a seat raised slightly above the others sat a man who evidently was speaker for the men of the jury. on a similar elevated seat was the woman speaker; this latter was lylda. near the center of the room, facing the judge and jury were two triangular spaces about twenty feet across, enclosed with a breast-high wall of stone. within each of these enclosures were perhaps ten or twelve people seated on small stone benches. directly facing the members of the jury and between them and the two enclosures, was a small platform raised about four feet above the floor, with several steps leading up to it from behind. a number of attendants dressed in the characteristic short tunics, with breastplates and a short sword hanging from the waist, stood near the enclosures, and along the sides of the room. the chemist leaned over and whispered to his friends: "those two enclosed places in the center are for the witnesses. over there are those testifying for the accused; the others are witnesses for the government. the platform is where the accused stands when----" he broke off suddenly. an expectant hush seemed to run over the room. a door at the side opened, and preceded and followed by two attendants a man entered, who walked slowly across the floor and stood alone upon the raised platform facing the jury. he was a man of extraordinarily striking look and demeanor. he stood considerably over six feet in height, with a remarkably powerful yet lean body. he was naked except for a cloth breech clout girdled about his loins. his appearance was not that of an oroid, for beside his greater height, and more muscular physique, his skin was distinctly of a more brownish hue. his hair was cut at the base of the neck in oroid fashion; it was black, with streaks of silver running through it. his features were large and cast in a rugged mold. his mouth was cruel, and wore now a sardonic smile. he stood erect with head thrown back and arms folded across his breast, calmly facing the men and women who were to judge him. the very young man gripped the chemist by the arm. "who is that?" he whispered. the chemist's lips were pressed together; he seemed deeply affected. "i did not know they caught him," he answered softly. "it must have been just this morning." the very young man looked at lylda. her face was placid, but her breast was rising and falling more rapidly than normal, and her hands in her lap were tightly clenched. the judge began speaking quietly, amid a deathlike silence. for over five minutes he spoke; once he was interrupted by a cheer, instantly stifled, and once by a murmur of dissent from several spectators on the balcony that called forth instant rebuke from the attendant stationed there. the judge finished his speech, and raised his golden scepter slowly before him. as his voice died away, lylda rose to her feet and facing the judge bowed low, with hands to her forehead. then she spoke a few words, evidently addressing the women before her. each of them raised her hands and answered in a monosyllable, as though affirming an oath. this performance was repeated by the men. the accused still stood silent, smiling sardonically. suddenly his voice rasped out with a short, ugly intonation and he threw his arms straight out before him. a murmur rose from the spectators, and several attendants leaned forward towards the platform. but the man only looked around at them contemptuously and again folded his arms. from one of the enclosures a woman came, and mounted the platform beside the man. the chemist whispered, "his wife; she is going to speak for him." but with a muttered exclamation and wave of his arm, the man swept her back, and without a word she descended the steps and reentered the railed enclosure. then the man turned and raising his arms spoke angrily to those seated in the enclosure. then he appealed to the judge. the chemist whispered in explanation: "he refuses any witnesses." at a sign from the judge the enclosure was opened and its occupants left the floor, most of them taking seats upon the balcony. "who is he?" the very young man wanted to know, but the chemist ignored his question. for perhaps ten minutes the man spoke, obviously in his own defence. his voice was deep and powerful, yet he spoke now seemingly without anger; and without an air of pleading. in fact his whole attitude seemed one of irony and defiance. abruptly he stopped speaking and silence again fell over the room. a man and a woman left the other enclosure and mounted the platform beside the accused. they seemed very small and fragile, as he towered over them, looking down at them sneeringly. the man and woman conferred a moment in whispers. then the woman spoke. she talked only a few minutes, interrupted twice by the judge, once by a question from lylda, and once by the accused himself. then for perhaps ten minutes more her companion addressed the court. he was a man considerably over middle age, and evidently, from his dress and bearing, a man of prominence in the nation. at one point in his speech it became obvious that his meaning was not clearly understood by the jury. several of the women whispered together, and one rose and spoke to lylda. she interrupted the witness with a quiet question. later the accused himself questioned the speaker until silenced by the judge. following this witness came two others. then the judge rose, and looking up to the balcony where the chemist and his companions were sitting, motioned to the chemist to descend to the floor below. the very young man tried once again with his whispered question "what is it?" but the chemist only smiled, and rising quietly left them. there was a stir in the court-room as the chemist crossed the main floor. he did not ascend the platform with the prisoner, but stood beside it. he spoke to the jury quietly, yet with a suppressed power in his voice that must have been convincing. he spoke only a moment, more with the impartial attitude of one who gives advice than as a witness. when he finished, he bowed to the court and left the floor, returning at once to his friends upon the balcony. following the chemist, after a moment of silence, the judge briefly addressed the prisoner, who stolidly maintained his attitude of ironic defiance. "he is going to ask the jury to give its verdict now," said the chemist in a low voice. lylda and her companion leader rose and faced their subordinates, and with a verbal monosyllable from each member of the jury the verdict was unhesitatingly given. as the last juryman's voice died away, there came a cry from the back of the room, a woman tore herself loose from the attendants holding her, and running swiftly across the room leaped upon the platform. she was a slight little woman, almost a child in appearance beside the man's gigantic stature. she stood looking at him a moment with heaving breast and great sorrowful eyes from which the tears were welling out and flowing down her cheeks unheeded. the man's face softened. he put his hands gently upon the sides of her neck. then, as she began sobbing, he folded her in his great arms. for an instant she clung to him. then he pushed her away. still crying softly, she descended from the platform, and walked slowly back across the room. hardly had she disappeared when there arose from the street outside a faint, confused murmur, as of an angry crowd gathering. the judge had left his seat now and the jury was filing out of the room. the chemist turned to his friends. "shall we go?" he asked. "this trial--" began the big business man. "you haven't told us its significance. this man--good god what a figure of power and hate and evil. who is he?" "it must have been evident to you, gentlemen," the chemist said quietly, "that you have been witnessing an event of the utmost importance to us all. i have to tell you of the crisis facing us; this trial is its latest development. that man--" the insistent murmur from the street grew louder. shouts arose and then a loud pounding from the side of the building. the chemist broke off abruptly and rose to his feet. "come outside," he said. they followed him through a doorway on to a balcony, overlooking the street. gathered before the court-house was a crowd of several hundred men and women. they surged up against its entrance angrily, and were held in check there by the armed attendants on guard. a smaller crowd was pounding violently upon a side door of the building. several people ran shouting down the street, spreading the excitement through the city. the chemist and his companions stood in the doorway of the balcony an instant, silently regarding this ominous scene. the chemist was just about to step forward, when, upon another balcony, nearer the corner of the building a woman appeared. she stepped close to the edge of the parapet and raised her arms commandingly. it was lylda. she had laid aside her court robe and stood now in her glistening silver tunic. her hair was uncoiled, and fell in dark masses over her white shoulders, blowing out behind her in the wind. the crowd hesitated at the sight of her, and quieted a little. she stood rigid as a statue for a moment, holding her arms outstretched. then, dropping them with a gesture of appeal she began to speak. at the sound of her voice, clear and vibrant, yet soft, gentle and womanly, there came silence from below, and after a moment every face was upturned to hers. gradually her voice rose in pitch. its gentle tone was gone now--it became forceful, commanding. then again she flung out her arms with a dramatic gesture and stood rigid, every line of her body denoting power--almost imperious command. abruptly she ceased speaking, and, as she stood motionless, slowly at first, the crowd silently dispersed. the street below was soon clear. even those onlookers at a distance turned the corner and disappeared. another moment passed, and then lylda swayed and sank upon the floor of the balcony, with her head on her arms against its low stone railing--just a tired, gentle, frightened little woman. "she did it--how wonderfully she did it," the very young man murmured in admiration. "we can handle them now," answered the chemist. "but each time--it is harder. let us get lylda and go home, gentlemen. i want to tell you all about it." he turned to leave the balcony. "who was the man? what was he tried for?" the very young man demanded. "that trial was the first of its kind ever held," the chemist answered. "the man was condemned to death. it was a new crime--the gravest we have ever had to face--the crime of treason." chapter xxiii lylda's plan back home, comfortably seated upon the broad balcony overlooking the lake, the three men sat waiting to hear their host's explanation of the strange events they had witnessed. lylda busied herself preparing a light noonday meal, which she served charmingly on the balcony while they talked. "my friends," the chemist began. "i tried to give you this morning, a picture of this world and the life i have been leading here. i think you understand, although i did not specifically say so, that all i said related to the time when i first came here. that you would call this life utopia, because of the way i outlined it, i do not doubt; or at least you would call it a state of affairs as near utopian as any human beings can approach. "all that is true; it was utopia. but gentlemen, it is so no longer. things have been changing of recent years, until now--well you saw what happened this morning. "i cannot account for the first cause of this trouble. perhaps the malite war, with its disillusionment to our people--i do not know. faith in human kindness was broken: the oroids could no longer trust implicitly in each other. a gradual distrust arose--a growing unrest--a dissatisfaction, which made no demands at first, nor seemed indeed to have any definite grievances of any sort. from it there sprang leaders, who by their greater intelligence created desires that fed and nourished their dissatisfaction--gave it a seemingly tangible goal that made it far more dangerous than it ever had been before. "about a year ago there first came into prominence the man whom you saw this morning condemned to death. his name is targo--he is a malite--full-blooded i believe, although he says not. for twenty years or more he has lived in orlog, a city some fifty miles from arite. his wife is an oroid. "targo, by his eloquence, and the power and force of his personality, won a large following in orlog, and to a lesser degree in many other cities. twice, some months ago, he was arrested and reprimanded; the last time with a warning that a third offence would mean his death." "what is he after?" asked the very young man. "the targos, as they are called, demand principally a different division of the land. under the present system, approximately one-third of all the land is in the hands of the government. of that, generally more than half lies idle most of the time. the targos wish to have this land divided among the citizens. they claim also that most of the city organizations do not produce as large a dividend as the targos could show under their own management. they have many other grievances that there is no reason for me to detail." "why not let them try out their theories in some city?" suggested the big business man. "they are trying them," the chemist answered. "there was a revolution in orlog about six months ago. several of its officials were assassinated--almost the first murders we have ever had. the targos took possession of the government--a brother of this man you saw this morning became leader of the city. orlog withdrew from the oroid government and is now handling its affairs as a separate nation." "i wonder----" began the big business man thoughtfully. "well, why not let them run it that way, if they want to?" "no reason, if they were sincere. but they are not sincere nor honest fundamentally. their leaders are for the most part malites, or oroids with malite blood. and they are fooling the people. their followers are all the more unintelligent, more gullible individuals, or those in whom there lies a latent criminal streak. "the thing doesn't work. sexual license is growing in orlog. crimes against women are becoming more and more frequent. offences committed by those prominent, or in authority, go unpunished. women's testimony is discredited, often by concerted lying on the part of men witnesses. "many families are leaving orlog--leaving their land and their homes deserted. in other cities where the targos threaten to gain control the same thing is happening. most of these refugees come to arite. we cannot take care of them; there is not enough land here." "why not take your army and clean them up?" suggested the very young man. they were seated around a little table, at which lylda was serving lunch. at the question she stopped in the act of pouring a steaming liquid from a little metal kettle into their dainty golden drinking cups and looked at the very young man gravely. "very easy it would be to do that perhaps," she said quietly. "but these targos, except a few--they are our own people. and they too are armed. we cannot fight them; we cannot kill them--our own people." "we may have to," said the chemist. "but you see, i did not realize, i could not believe the extent to which this targo could sway the people. nor did i at first realize what evils would result if his ideas were carried out. he has many followers right here in arite. you saw that this morning." "how did you catch him?" interrupted the very young man. "yesterday he came to arite," said lylda. "he came to speak. with him came fifty others. with them too came his wife to speak here, to our women. he thought we would do nothing; he defied us. there was a fight--this morning--and many were killed. and we brought him to the court--you saw." "it is a serious situation," said the doctor. "i had no idea----" "we can handle it--we must handle it," said the chemist. "but as lylda says, we cannot kill our own people--only as a last desperate measure." "suppose you wait too long," suggested the big business man. "you say these targos are gaining strength every day. you might have a very bad civil war." "that was the problem," answered the chemist. "but now you come," said lylda. "you change it all when you come down to us out of the great beyond. our people, they call you genii of the master, they----" "oh gee, i never thought of that," murmured the very young man. "what _do_ you think of us?" "they think you are supernatural beings of course," the chemist said smiling. "yet they accept you without fear and they look to you and to me for help." "this morning, there at the court," said lylda, "i heard them say that targo spoke against you. devils, he said, from the great blue star, come here with evil for us all. and they believe him, some of them. it was for that perhaps they acted as they did before the court. in arite now, many believe in targo. and it is bad, very bad." "the truth is," added the chemist, "your coming, while it gives us unlimited possibilities for commanding the course of events, at the same time has precipitated the crisis. naturally no one can understand who or what you are. and as lylda says, the targos undoubtedly are telling the people you come to ally yourself with me for evil. there will be thousands who will listen to them and fear and hate you--especially in some of the other cities." "what does the king say?" asked the doctor. "we will see him to-morrow. he has been anxiously waiting for you. but you must not forget," the chemist added with a smile, "the king has had little experience facing strife or evil-doing of any kind. it was almost unknown until recently. it is i, and you, gentlemen, who are facing the problem of saving this nation." the very young man's face was flushed, and his eyes sparkled with excitement. "we can do anything we like," he said. "we have the power." "ay, that is it," said lylda. "the power we have. but my friend, we cannot use it. not for strife, for death; we cannot." "the execution of targo will cause more trouble," said the chemist thoughtfully. "it is bound to make----" "when will you put him to death?" asked the big business man. "to-morrow he dies," lylda answered. "to-morrow, before the time of sleep." "there will be trouble," said the chemist again. "we are in no personal danger of course, but, for the people who now believe in targo, i am afraid----" "a plan i have made," said lylda. she sat forward tensely in her chair, brushing her hair back from her face with a swift gesture. "a plan i have made. it is the only way--i now think--that may be there comes no harm to our people. it is that we want to do, if we can." she spoke eagerly, and without waiting for them to answer, went swiftly on. "this drug that you have brought, i shall take it. and i shall get big. oh, not so very big, but big enough to be the height of a man it may be ten times. then shall i talk to the people--i, lylda--woman of the master, and then shall i tell them that this power, this magic, is for good, not for evil, if only they will give up targo and all who are with him." "i will take it with you," said the chemist. "together we----" "no, no, my husband. alone i must do this. ah, do you not know they say these stranger devils with their magic come for evil? and you too, must you not forget, once were a stranger just as they. that the people know--that they remember. "but i--i--lylda--a woman of the oroids i am--full-blooded oroid, no stranger. and they will believe me--a woman--for they know i cannot lie. "i shall tell them i am for good, for kindness, for all we had, that time before the malite war, when every one was happy. and if they will not believe, if as i say they will not do, then shall my power be indeed for evil, and all who will obey me not shall die. but they will believe--no need will there be to threaten. "to many cities i will go. and in them, all of those who want to live by targo's law will i send to orlog. and all in orlog who believe him not, will i tell to leave, and to the other cities go to make their homes. then orlog shall be targo's city. and to-morrow he will not die, but go there into orlog and become their king. for i shall say it may be there are some who like his rule of evil. or it may be he is good in different fashion, and in time can make us see that his law too, is just and kind. "then shall live in orlog all who wish to stay, and we shall watch their rule, but never shall we let them pass beyond their borders. for if they do, then shall we kill them. "all this i can do, my husband, if you but will let me try. for me they will believe, a woman, oroid all of blood--for they know women do not lie." she stopped and the fire in her eyes changed to a look of gentle pleading. "if you will but let me try," she finished. "my husband--please." the chemist glanced at his friends who sat astonished by this flow of eager, impassioned words. then he turned again to lylda's intent, pleading face, regarding her tenderly. "you are very fine, little mother of my son," he said gently, lapsing for a moment into her own style of speech. "it could do no harm," he added thoughtfully "and perhaps----" "let her try it," said the doctor. "no harm could come to her." "no harm to me could come," said lylda quickly. "and i shall make them believe. i can, because i am a woman, and they will know i tell the truth. ah, you will let me try, my husband--please?" the chemist appealed to the others. "they will believe her, many of them," he said. "they will leave orlog as she directs. but those in other cities will still hold to targo, they will simply remain silent for a time. what their feelings will be or are we cannot tell. some will leave and go to orlog of course, for lylda will offer freedom of their leader and to secure that they will seem to agree to anything. "but after all, they are nothing but children at heart, most of them. to-day, they might believe in lylda; to-morrow targo could win them again." "he won't get a chance," put in the very young man quickly. "if she says we kill anybody who talks for targo outside of orlog, that goes. it's the only way, isn't it?" "and she might really convince them--or most of them," added the doctor. "you will let me try?" asked lylda softly. the chemist nodded. lylda sprang to her feet. her frail little body was trembling with emotion; on her face was a look almost of exaltation. "you _will_ let me try," she cried. "then i shall make them believe. here, now, this very hour, i shall make them know the truth. and they, my own people, shall i save from sorrow, misery and death." she turned to the chemist and spoke rapidly. "my husband, will you send oteo now, up into the city. him will you tell to have others spread the news. all who desire an end to targo's rule, shall come here at once. and all too, who in him believe, and who for him want freedom, they shall come too. let oteo tell them magic shall be performed and lylda will speak with them. "make haste, my husband, for now i go to change my dress. not as the master's woman will i speak, but as lylda--oroid woman--woman of the people." and with a flashing glance, she turned and swiftly left the balcony. chapter xxiv lylda acts "she'll do it," the very young man murmured, staring at the doorway through which lylda had disappeared. "she can do anything." the chemist rose to his feet. "i'll send oteo. will you wait here gentlemen? and will you have some of the drugs ready for lylda? you have them with you?" the men nodded. "how about lylda carrying the drugs?" asked the very young man. "and what about her clothes?" "i have already made a belt for lylda and for myself--some time ago," the chemist answered. "during the first year i was here i made several experiments with the drugs. i found that almost anything within the immediate--shall i say influence of the body, will contract with it. almost any garment, even a loose robe will change size. you found that to be so to some extent. those belts you wore down--" "that's true," agreed the doctor, "there seems to be considerable latitude----" "i decided," the chemist went on, "that immediately after your arrival we should all wear the drugs constantly. you can use the armpit pouches if you wish; lylda and i will wear these belts i have made." oteo, the chemist's personal servant, a slim youth with a bright, intelligent face, listened carefully to his master's directions and then left the house hurriedly, running up the street towards the center of the city. once or twice he stopped and spoke to passers-by for a moment, gathering a crowd around him each time. the chemist rejoined his friends on the balcony. "there will be a thousand people here in half an hour," he said quietly. "i have sent a message to the men in charge of the government workshops; they will have their people cease work to come here." lylda appeared in a few moments more. she was dressed as the chemist had seen her first through the microscope--in a short, grey skirt reaching from waist to knees. only now she wore also two circular metal discs strapped over her breasts. her hair was unbound and fell in masses forward over her shoulders. around her waist was a broad girdle of golden cloth with small pouches for holding the chemicals. she took her place among the men quietly. "see, i am ready," she said with a smile. "oteo, you have sent him?" the chemist nodded. lylda turned to the doctor. "you will tell me, what is to do with the drugs?" they explained in a few words. by now a considerable crowd had gathered before the house, and up the street many others were hurrying down. directly across from the entrance to lylda's garden, back of the bluff at the lake front, was a large open space with a fringe of trees at its back. in this open space the crowd was collecting. the chemist rose after a moment and from the roof-top spoke a few words to the people in the street below. they answered him with shouts of applause mingled with a hum of murmured anger underneath. the chemist went back to his friends, his face set and serious. as he dropped in his chair lylda knelt on the floor before him, laying her arms on his knees. "i go to do for our people the best i can," she said softly, looking up into his face. "now i go, but to you i will come back soon." the chemist tenderly put his hand upon the glossy smoothness of her hair. "i go--now," she repeated, and reached for one of the vials under her arm. holding it in her hand, she stared at it a moment, silently, in awe. then she shuddered like a frightened child and buried her face in the chemist's lap, huddling her little body up close against his legs as if for protection. the chemist did not move nor speak, but sat quiet with his hand gently stroking her hair. in a moment she again raised her face to his. her long lashes were wet with tears, but her lips were smiling. "i am ready--now," she said gently. she brushed her tears from her eyes and rose to her feet. drawing herself to her full height, she tossed back her head and flung out her arms before her. "no one can know i am afraid--but you," she said. "and i--shall forget." she dropped her arms and stood passive. "i go now to take the drug--there in the little garden behind, where no one can notice. you will come down?" the big business man cleared his throat. when he spoke his voice was tremulous with emotion. "how long will you be gone--lylda?" he asked. the woman turned to him with a smile. "soon will i return, so i believe," she answered. "i go to orlog, to raito, and to tele. but never shall i wait, nor speak long, and fast will i walk.... before the time of sleep has descended upon us, i shall be here." in the little garden behind the house, out of sight of the crowd on the other side, lylda prepared to take the drug. she was standing there, with the four men, when loto burst upon them, throwing himself into his mother's arms. "oh, _mamita_, _mamita_," he cried, clinging to her. "there in the street outside, they say such terrible things----of you _mamita_. 'the master's woman' i heard one say, 'she has the evil magic.' and another spoke of targo. and they say he must not die, or there will be death for those who kill him." lylda held the boy close as he poured out his breathless frightened words. "no matter, little son," she said tenderly. "to _mamita_ no harm can come--you shall see. did my father teach you well to-day?" "but _mamita_, one man who saw me standing, called me an evil name and spoke of you, my mother lylda. and a woman looked with a look i never saw before. i am afraid, _mamita_." with quivering lips that smiled, lylda kissed the little boy tenderly and gently loosening his hold pushed him towards his father. "the master's son, loto, never can he be afraid," she said with gentle reproof. "that must you remember--always." the little group in the garden close up against the house stood silent as lylda took a few grains of the drug. the noise and shouts of the crowd in front were now plainly audible. one voice was raised above the others, as though someone were making a speech. loto stood beside his father, and the chemist laid his arm across the boy's shoulder. as lylda began visibly to increase in size, the boy uttered a startled cry. meeting his mother's steady gaze he shut his lips tight, and stood rigid, watching her with wide, horrified eyes. lylda had grown nearly twice her normal size before she spoke. then, smiling down at the men, she said evenly, "from the roof, perhaps, you will watch." "you know what to do if you grow too large," the doctor said huskily. "i know, my friend. i thank you all. and good-bye." she met the chemist's glance an instant. then abruptly she faced about and walking close to the house, stood at its further corner facing the lake. after a moment's hesitation the chemist led his friends to the roof. as they appeared at the edge of the parapet a great shout rolled up from the crowd below. nearly a thousand people had gathered. the street was crowded and in the open space beyond they stood in little groups. on a slight eminence near the lake bluff, a man stood haranguing those around him. he was a short, very thickset little man, with very long arms--a squat, apelike figure. he talked loudly and indignantly; around him perhaps a hundred people stood listening, applauding at intervals. when the chemist appeared this man stopped with a final phrase of vituperation and a wave of his fist towards the house. the chemist stood silent, looking out over the throng. "how large is she now?" he asked the very young man softly. the very young man ran across the roof to its farther corner and was back in an instant. "they'll see her soon--look there." his friends turned at his words. at the corner of the house they could just see the top of lylda's head above the edge of the parapet. as they watched she grew still taller and in another moment her forehead appeared. she turned her head, and her great eyes smiled softly at them across the roof-top. in a few moments more (she had evidently stopped growing) with a farewell glance at her husband, she stepped around the corner of the house into full view of the crowd--a woman over sixty feet tall, standing quietly in the garden with one hand resting upon the roof of the house behind her. a cry of terror rose from the people as she appeared. most of those in the street ran in fright back into the field behind. then, seeing her standing motionless with a gentle smile on her face, they stopped, irresolute. a few held their ground, frankly curious and unafraid. others stood sullen and defiant. when the people had quieted a little lylda raised her arms in greeting and spoke, softly, yet with a voice that carried far away over the field. as she talked the people seemed to recover their composure rapidly. her tremendous size no longer seemed to horrify them. those who obviously at first were friendly appeared now quite at ease; the others, with their lessening terror, were visibly more hostile. once lylda mentioned the name of targo. a scattered shout came up from the crowd; the apelike man shouted out something to those near him, and then, leaving his knoll disappeared. as lylda continued, the hostile element in the crowd grew more insistent. they did not listen to her now but shouted back, in derision and defiance. then suddenly a stone was thrown; it struck lylda on the breast, hitting her metal breastplate with a thud and dropping at her feet. as though at a signal a hail of stones flew up from the crowd, most of them striking lylda like tiny pebbles, a few of the larger ones bounding against the house, or landing on its roof. at this attack lylda abruptly stopped speaking and took a step forward menacingly. the hail of stones continued. then she turned towards the roof-top, where the men and the little boy stood behind the parapet, sheltering themselves from the flying stones. "only one way there is," said lylda sadly, in a soft whisper that they plainly heard above the noise of the crowd. "i am sorry, my husband--but i must." a stone struck her shoulder. she faced the crowd again; a gentle look of sorrow was in her eyes, but her mouth was stern. in the street below at the edge of the field the squat little man had reappeared. it was from here that most of the stones seemed to come. "that man there--by the road----" the chemist pointed. "one of targo's----" in three swift steps lylda was across the garden, with one foot over the wall into the street. reaching down she caught the man between her huge fingers, and held him high over her head an instant so that all might see. the big crowd was silent with terror; the man high in the air over their heads screamed horribly. lylda hesitated only a moment more; then she threw back her arm and, with a great great sweep, flung her screaming victim far out into the lake. chapter xxv the escape of targo "i am very much afraid it was a wrong move," said the chemist gravely. they were sitting in a corner of the roof, talking over the situation. lylda had left the city; the last they had seen of her, she was striding rapidly away, over the country towards orlog. the street and field before the house now was nearly deserted. "she had to do it, of course," the chemist continued, "but to kill targo's brother----" "i wonder," began the big business man thoughtfully. "it seems to me this disturbance is becoming far more serious than we think. it isn't so much a political issue now between your government and the followers of targo, as it is a struggle against those of us who have this magic, as they call it." "that's just the point," put in the doctor quickly. "they are making the people believe that our power of changing size is a menace that----" "if i had only realized," said the chemist. "i thought your coming would help. apparently it was the very worst thing that could have happened." "not for you personally," interjected the very young man. "we're perfectly safe--and lylda, and loto." he put his arm affectionately around the boy who sat close beside him. "you are not afraid, are you, loto?" "now i am not," answered the boy seriously. "but this morning, when i left my grandfather, coming home----" "you were afraid for your mother. that was it, wasn't it?" finished the very young man. "does your grandfather teach you?" "yes--he, and father, and mother." "i want you to see lylda's father," said the chemist. "there is nothing we can do now until lylda returns. shall we walk up there?" they all agreed readily. "i may go, too?" loto asked, looking at his father. "you have your lessons," said the chemist. "but, my father, it is so very lonely without mother," protested the boy. the chemist smiled gently. "afraid, little son, to stay with oteo?" "he's not afraid," said the very young man stoutly. the little boy looked from one to the other of them a moment silently. then, calling oteo's name, he ran across the roof and down into the house. "five years ago," said the chemist, as the child disappeared, "there was hardly such an emotion in this world as fear or hate or anger. now the pendulum is swinging to the other extreme. i suppose that's natural, but----" he ended with a sigh, and, breaking his train of thought, rose to his feet. "shall we start?" lylda's father greeted them gravely, with a dignity, and yet obvious cordiality that was quite in accord with his appearance. he was a man over sixty. his still luxuriant white hair fell to his shoulders. his face was hairless, for in this land all men's faces were as devoid of hair as those of the women. he was dressed in a long, flowing robe similar to those his visitors were wearing. "because--you come--i am glad," he said with a smile, as he shook hands in their own manner. he spoke slowly, with frequent pauses, as though carefully picking his words. "but--an old man--i know not the language of you." he led them into a room that evidently was his study, for in it they saw many strange instruments, and on a table a number of loosely bound sheets of parchment that were his books. they took the seats he offered and looked around them curiously. "there is the clock we spoke of," said the chemist, indicating one of the larger instruments that stood on a pedestal in a corner of the room. "reoh will explain it to you." their host addressed the chemist. "from oteo i hear--the news to-day is bad?" he asked with evident concern. "i am afraid it is," the chemist answered seriously. "and lylda?" the chemist recounted briefly the events of the day. "we can only wait until lylda returns," he finished. "to-morrow we will talk with the king." "bad it is," said the old man slowly; "very bad. but--we shall see----" the very young man had risen to his feet and was standing beside the clock. "how does it work?" he asked. "what time is it now?" reoh appealed to his son-in-law. "to tell of it--the words i know not." the chemist smiled. "you are too modest, my father. but i will help you out, if you insist." he turned to the others, who were gathered around him, looking at the clock. "our measurement of our time here," he began, "like yours, is based on----" "excuse me," interrupted the very young man. "i just want to know first what time it is now?" "it is in the fourth eclipse," said the chemist with a twinkle. the very young man was too surprised by this unexpected answer to question further, and the chemist went on. "we measure time by the astronomical movements, just as you do in your world. one of the larger stars has a satellite which revolves around it with extreme rapidity. here at arite, this satellite passes nearly always directly behind its controlling star. in other words, it is eclipsed. ten of these eclipses measure the passage of our day. we rise generally at the first eclipse or about that time. it is now the fourth eclipse; you would call it late afternoon. do you see?" "how is the time gauged here?" asked the big business man, indicating the clock. the instrument stood upon a low stone pedestal. it consisted of a transparent cylinder about twelve inches in diameter and some four feet high, surmounted by a large circular bowl. the cylinder was separated from the bowl by a broad disc of porous stone; a similar stone section divided the cylinder horizontally into halves. from the bowl a fluid was dropping in a tiny stream through the top stone segment into the upper compartment, which was now about half full. this in turn filtered through the second stone into the lower compartment. this lower section was marked in front with a large number of fine horizontal lines, an equal distance apart, but of unequal length. in it the fluid stood now just above one of the longer lines-the fourth from the bottom. on the top of this fluid floated a circular disc almost the size of the inside diameter of the cylinder. the chemist explained. "it really is very much like the old hour-glass we used to have in your world. this filters liquid instead of sand. you will notice the water filters twice." he indicated the two compartments. "that is because it is necessary to have a liquid that is absolutely pure in order that the rate at which it filters through this other stone may remain constant. the clock is carefully tested, so that for each eclipse the water will rise in this lower part of the cylinder, just the distance from here to here." the chemist put his fingers on two of the longer marks. "very ingenious," remarked the doctor. "is it accurate?" "not so accurate as your watches, of course," the chemist answered. "but still, it serves the purpose. these ten longer lines, you see, mark the ten eclipses that constitute one of our days. the shorter lines between indicate halves and quarter intervals." "then it is only good for one day?" asked the very young man. "how do you set it?" "it resets automatically each day, at the beginning of the first eclipse. this disc," the chemist pointed to the disc floating on the water in the lower compartment. "this disc rises with the water on which it is floating. when it reaches the top of it, it comes in contact with a simple mechanism--you'll see it up there--which opens a gate below and drains out the water in a moment. so that every morning it is emptied and starts filling up again. all that is needed is to keep this bowl full of water." "it certainly seems very practical," observed the big business man. "are there many in use?" "quite a number, yes. this clock was invented by reoh, some thirty years ago. he is the greatest scientist and scholar we have." the old man smiled deprecatingly at this compliment. "are these books?" asked the very young man; he had wandered over to the table and was fingering one of the bound sheets of parchment. "they are reoh's chronicles," the chemist answered. "the only ones of their kind in arite." "what's this?" the very young man pointed to another instrument. "that is an astronomical instrument, something like a sextant--also an invention of reoh's. here is a small telescope and----" the chemist paused and went over to another table standing at the side of the room. "that reminds me, gentlemen," he continued; "i have something here in which you will be greatly interested." "what you--will see," said reoh softly, as they gathered around the chemist, "you only, of all people, can understand. each day i look, and i wonder; but never can i quite believe." "i made this myself, nearly ten years ago," said the chemist, lifting up the instrument; "a microscope. it is not very large, you see; nor is it very powerful. but i want you to look through it." with his cigar-lighter he ignited a short length of wire that burned slowly with a brilliant blue spot of light. in his hand he held a small piece of stone. "i made this microscope hoping that i might prove with it still more conclusively my original theory of the infinite smallness of human life. for many months i searched into various objects, but without success. finally i came upon this bit of rock." the chemist adjusted it carefully under the microscope with the light shining brilliantly upon it. "you see i have marked one place; i am going to let you look into it there." the doctor stepped forward. as he looked they heard his quick intake of breath. after a moment he raised his head. on his face was an expression of awe too deep for words. he made place for the others, and stood silent. when the very young man's turn came he looked into the eyepiece awkwardly. his heart was beating fast; for some reason he felt frightened. at first he saw nothing. "keep the other eye open," said the chemist. the very young man did as he was directed. after a moment there appeared before him a vast stretch of open country. as from a great height he stared down at the scene spread out below him. gradually it became clearer. he saw water, with the sunlight--his own kind of sunlight it seemed--shining upon it. he stared for a moment more, dazzled by the light. then, nearer to him, he saw a grassy slope, that seemed to be on a mountain-side above the water. on this slope he saw animals grazing, and beside them a man, formed like himself. the chemist's voice came to him from far away. "we are all of us here in a world that only occupies a portion of one little atom of the gold of a wedding-ring. yet what you see there in that stone----" the very young man raised his head. before him stood the microscope, with its fragment of stone gleaming in the blue light of the burning wire. he wanted to say something to show them how he felt, but no words came. he looked up into the chemist's smiling face, and smiled back a little foolishly. "every day i look," said reoh, breaking the silence. "and i see--wonderful things. but never really--can i believe." at this moment there came a violent rapping upon the outer door. as reoh left the room to open it, the very young man picked up the bit of stone that the chemist had just taken from the microscope. "i wish--may i keep it?" he asked impulsively. the chemist smiled and nodded, and the very young man was about to slip it into the pocket of his robe when reoh hastily reentered the room, followed by oteo. the youth was breathing heavily, as though he had been running, and on his face was a frightened look. "bad; very bad," said the old man, in a tone of deep concern, as they came through the doorway. "what is it, oteo?" asked the chemist quickly. the boy answered him with a flood of words in his native tongue. the chemist listened quietly. then he turned to his companions. "targo has escaped," he said briefly. "they sent word to me at home, and oteo ran here to tell me. a crowd broke into the court-house and released him. oteo says they went away by water, and that no one is following them." the youth, who evidently understood english, added something else in his own language. "he says targo vowed death to all who have the magic power. he spoke in the city just now, and promised them deliverance from the giants." "good lord," murmured the very young man. "he has gone to orlog probably," the chemist continued. "we have nothing to fear for the moment. but that he could speak, in the centre of arite, after this morning, and that the people would listen--" "it seems to me things are getting worse every minute," said the big business man. oteo spoke again. the chemist translated. "the police did nothing. they simply stood and listened, but took no part." "bad; very bad," repeated the old man, shaking his head. "what we should do i confess i cannot tell," said the chemist soberly. "but that we should do something drastic is obvious." "we can't do anything until lylda gets back," declared the very young man. "we'll see what she has done. we might have had to let targo go anyway." the chemist started towards the door. "to-night, by the time of sleep, reoh," he said to the old man, "i expect lylda will have returned. you had better come to us then with aura. i do not think you should stay here alone to sleep to-night." "in a moment--aura comes," reoh answered. "we shall be with you--very soon." the chemist motioned to his companions, and with obvious reluctance on the part of the very young man they left, followed by oteo. on the way back the city seemed quiet--abnormally so. the streets were nearly deserted; what few pedestrians they met avoided them, or passed them sullenly. they were perhaps half-way back to the chemist's house when the very young man stopped short. "i forgot that piece of stone," he explained, looking at them queerly. "go on. i'll be there by the time you are," and disregarding the chemist's admonition that he might get lost he left them abruptly and walked swiftly back over the way they had come. without difficulty, for they had made few turns, the very young man located reoh's house. as he approached he noticed the figure of a man lounging against a further corner of the building; the figure disappeared almost as soon as he saw it. it was a trivial incident, but, somehow, to the very young man, it held something in it of impending danger. he did not knock on the outer door, but finding it partly open, he slowly pushed it wider and stepped quietly into the hallway beyond. he was hardly inside when there came from within the house a girl's scream--a cry of horror, abruptly stifled. for an instant, the very young man stood hesitating. then he dashed forward through an open doorway in the direction from which the cry had seemed to come. the room into which he burst was reoh's study; the room he had left only a few moments before. on the floor, almost across his path, lay the old man, with the short blade of a sword buried to the hilt in his breast. in a corner of the room a young oroid girl stood with her back against the wall. her hands were pressed against her mouth; her eyes were wide with terror. bending over the body on the floor with a hand at its armpit, knelt the huge, gray figure of a man. at the sound of the intruder's entrance he looked up quickly and sprang to his feet. the very young man saw it was targo! chapter xxvi the abduction when the very young man left them so unceremoniously the chemist and his companions continued on their way home, talking earnestly over the serious turn affairs had taken. of the three, the big business man appeared the most perturbed. "lylda isn't going to accomplish anything," he said. "it won't work. the thing has gone too far. it isn't politics any longer; it's a struggle against us--a hatred and fear of our supernatural powers." "if we had never come----" began the doctor. "it probably would have worked out all right," finished the big business man. "but since we're here----" "we could leave," the doctor suggested. "it has gone too far; i agree with you," the chemist said. "your going would not help. they would never believe i did not still possess the magic. and now, without the drugs i might not be able to cope with affairs. it is a very serious situation." "and getting worse all the time," added the big business man. when they arrived at the chemist's home loto did not run out to meet them as the chemist expected. they called his name, but there was no answer. inside the house they perceived at once that something was wrong. the living-room was in disorder; some of the pieces of furniture had been overturned, and many of the smaller articles were scattered about the floor. even the wall-hangings had been torn down. in sudden fear the chemist ran through the building, calling to loto. everywhere he saw evidence of intruders, who had ransacked the rooms, as though making a hasty search. in one of the rooms, crouched on the floor, he came upon eena, lylda's little serving-maid. the girl was stricken dumb with terror. at the sight of her master she sobbed with relief, and after a few moments told him what had happened. when the chemist rejoined his friends in the lower room his face was set and white. the girl followed him closely, evidently afraid to be left alone. the chemist spoke quietly, controlling his emotion with obvious difficulty. "loto has been stolen!" he said. "targo and four of his men were here soon after we left. eena saw them and hid. they searched the house----" "for the drugs," muttered the doctor under his breath. "----and then left, taking loto with them." "which way did they go?" asked the big business man. "good god, what a thing!" "they went by water, in a large boat that was waiting for them here," answered the chemist. "how long ago?" asked the doctor quickly. "we have not been gone very long." "an hour probably, not much more." eena said something to her master and began to cry softly. "she says they left a little while ago. three of the men took loto away in the boat. she watched them from the window upstairs." "_targo aliá_," said the girl. "one of the men was targo," said the chemist. he went to one of the windows overlooking the lake; the doctor stood beside him. there was no boat in sight. "they cannot have got very far," said the doctor. "those islands there----" "they would take him to orlog," said the chemist. "about fifty miles." the doctor turned back to the room. "we can get them. you forget--these drugs--the power they give us. oh, will." he called the big business man over to them; he spoke hurriedly, with growing excitement. "what do you think, will? that boat--they've got loto--it can't be very far. we can make ourselves so large in half an hour we can wade all over the lake. we can get it. what do you think?" the chemist dropped into a chair with his head in his hands. "let me think--just a moment, frank. i know the power we have; i know we can do almost anything. that little boy of mine--they've got him. let me think--just a moment." he sat motionless. the doctor continued talking in a lower tone to the big business man by the window. in the doorway oteo stood like a statue, motionless, except for his big, soft eyes that roved unceasingly over the scene before him. after a moment eena ceased her sobbing and knelt beside the chemist, looking up at him sorrowfully. "i cannot believe," said the chemist finally, raising his head, "that the safest way to rescue loto is by the plan you have suggested." he spoke with his usual calm, judicial manner, having regained control of himself completely. "i understand now, thoroughly, and for the first time, the situation we are facing. it is, as you say, a political issue no longer. targo and his closest followers have convinced a very large proportion of our entire nation, i am certain, that myself, and my family, and you, the strangers, are possessed of a diabolical power that must be annihilated. targo will never rest until he has the drugs. that is why he searched this house. "he has abducted loto for the same purpose. he will--not hurt loto--i am convinced of that. probably he will send someone to-morrow to demand the drugs as the price of loto's life. but don't you understand? targo and his advisers, and even the most ignorant of the people, realize what power we have. lylda showed them that when she flung targo's brother out into the lake to-day. but we cannot use this power openly. for, while it makes us invincible, it makes them correspondingly desperate. they are a peculiar people. throughout the whole history of the race they have been kindly, thoughtless children. now they are aroused. the pendulum has swung to the other extreme. they care little for their lives. they are still children--children who will go to their death unreasoning, fighting against invincibility. "that is something we must never overlook, for it is a fact. we cannot run amuck as giants over this world and hope to conquer it. we could conquer it, yes; but only when the last of its inhabitants had been killed; stamped out like ants defending their hill from the attacks of an elephant. don't you see i am right?" "then lylda----" began the doctor, as the chemist paused. "lylda will fail. her venture to-day will make matters immeasurably worse." "you're right," agreed the big business man. "we should have realized." "so you see we cannot make ourselves large and recapture loto by force. they would anticipate us and kill him." "then what shall we do?" demanded the doctor. "we must do something." "that we must decide carefully, for we must make no more mistakes. but we can do nothing at this moment. the lives of all of us are threatened. we must not allow ourselves to become separated. we must wait here for lylda. reoh and aura must stay with us. then we can decide how to rescue loto and what to do after that. but we must keep together." "jack ought to be here by now," said the big business man. "i hope reoh and aura come with him." for over an hour they waited, and still the very young man did not come. they had just decided to send oteo to see what had become of him and to bring down reoh and his daughter, when lylda unexpectedly returned. it was eena, standing at one of the side windows, who first saw her mistress. a cry from the girl brought them all to the window. far away beyond the city they could see the gigantic figure of lylda, towering several hundred feet in the air. as she came closer she seemed to stop, near the outskirts of the city, and then they saw her dwindling in size until she disappeared, hidden from their view by the houses near at hand. in perhaps half an hour more she reappeared, picking her way carefully down the deserted street towards them. she was at this time about forty feet tall. at the corner, a hundred yards away from them a little group of people ran out, and, with shouts of anger, threw something at her as she passed. she stooped down towards them, and immediately they scurried for safety out of her reach. once inside of her own garden, where the chemist and his companions were waiting, lylda lost no time in becoming her normal size again. as she grew smaller, she sat down with her back against a little tree. her face was white and drawn; her eyes were full of tears as she looked at her husband and his friends. when the drug had ceased to act, the chemist sat beside her. she had started out only a few hours before a crusader, dominant, forceful; she came back now, a tired, discouraged little woman. the chemist put his arm around her protectingly, drawing her drooping body towards him. "very bad news, lylda, we know," he said gently. "oh, my husband," she cried brokenly. "so sorry i am--so very sorry. the best i knew i did. and it was all so very bad--so very bad----" she broke off abruptly, looking at him with her great, sorrowful eyes. "tell us lylda," he said softly. "to many cities i went," she answered. "and i told the people all i meant to say. some of them believed. but they were not many, and of the others who did not believe, they were afraid, and so kept they silent. then into orlog i went, and in the public square i spoke--for very long, because, for some reason i know not, at first they listened. "but no one there believed. and then, my husband, at last i knew why i could not hope to gain my way. it is not because they want targo's rule that they oppose us. it was, but it is so no longer. it is because they have been made to fear these drugs we have. for now, in orlog, they are shouting death to all the giants. forgotten are all their cries for land--the things that targo promised, and we in arite would not give. it is death to all the giants they are shouting now: death to you, to me, to us all, because we have these drugs." "did they attack you?" asked the big business man. "many things they threw," lylda answered. "but i was so big," she smiled a little sad, twisted smile. "what they could do was as nothing. and because of that they fear and hate us so; yet never have i seen such fearless things as those they did. death to the giants was their only cry. and i could have killed them--hundreds, thousands--yet never could i have made them stop while yet they were alive. "i told them targo i would free. and in orlog they laughed. for they said that he would free himself before i had returned." "he did," muttered the big business man. "targo escaped this afternoon," the chemist explained. "he went to orlog by boat and took----" he stopped abruptly. "come into the house, lylda," he added gently; "there are other things, my wife, of which we must speak." he rose to his feet, pulling her up with him. "where is jack," she asked, looking at the big business man, who stood watching her gravely. "and where is loto? does he not want to see his mother who tried so----" she put her arms around the chemist's neck. "so very hard i tried," she finished softly. "so very hard, because--i thought----" the chemist led her gently into the house. the doctor started to follow, but the big business man held him back. "it is better not," he said in an undertone, "don't you think?" oteo was standing near them, and the big business man motioned to him. "besides," he added, "i'm worried about jack. i think we ought to go up after him. i don't think it ought to take us very long." "with oteo--he knows the way," agreed the doctor. "it's devilish strange what's keeping that boy." they found that although oteo spoke only a few words of english, he understood nearly everything they said, and waiting only a moment more, they started up into the city towards reoh's home. in the living-room of the house, the chemist sat lylda gently down on a cushion in front of the hearth. sitting beside her, he laid his hand on hers that rested on her knee. "for twelve years, lylda, we have lived together," he began slowly. "and no sorrow has come to us; no danger has threatened us or those we loved." he met his wife's questioning gaze unflinchingly and went on: "you have proved yourself a wonderful woman, my wife. you never knew--nor those before you--the conflict of human passions. no danger before has ever threatened you or those you loved." he saw her eyes grow wider. "very strange you talk, my husband. there is something----" "there is something, lylda. to-day you have seen strife, anger, hate and--and death. you have met them all calmly; you have fought them all justly, like a woman--a brave, honest oroid woman, who can wrong no one. there is something now that i must tell you." he saw the growing fear in her eyes and hurried on. "loto, to-day--this afternoon----" the woman gave a little, low cry of anguish, instantly repressed. her hand gripped his tightly. "no, no, lylda, not that," he said quickly, "but this afternoon while we were all away--loto was here alone with eena--targo with his men came. they did not hurt loto; they took him away in a boat to orlog." he stopped abruptly. lylda's eyes never left his face. her breath came fast; she put a hand to her mouth and stifled the cry that rose to her lips. "they will not hurt him, lylda; that i know. and soon we will have him back." for a moment more her searching eyes stared steadily into his. he heard the whispered words, "my little son--with targo," come slowly from her lips; then with a low, sobbing cry she dropped senseless into his arms. chapter xxvii aura the very young man involuntarily took a step backward as he met targo's eyes, glaring at him across the old man's body. the girl in the corner gave another cry--a cry of fright and horror, yet with a note of relief. the very young man found himself wondering who she was; then he knew. his first impulse was to leap across the room towards her. he thought of the chemicals and instinctively his hand went to his armpit. but he knew there was no time for that. he hesitated one brief instant. as he stood rigid targo stooped swiftly and grasped the dagger in his victim's breast. the girl screamed again, louder this time, and like a mask the very young man's indecision fell from him. he stood alert, clear-headed. here was an enemy threatening him--an enemy he must fight and overcome. in the second that targo bent down the very young man bounded forward, and with a leap that his football days had taught him so well how to make, he landed squarely upon the bare, broad back of his antagonist. the impact of his weight forced targo down upon the floor, and losing his balance he fell, with the very young man on top of him. they hit the leg of the table as they rolled over, and something dropped from it to the floor, striking the stone surface with a thud. the knife still stuck in the dead man's body. the very young man thought he could reach it, but his opponent's great arms were around him now and held him too tightly. he tried to pull himself loose, but could not. then he rolled partly over again, and met targo's eyes above, leering triumphantly down at him. he looked away and wrenched his right arm free. across the room he could see the girl still crouching in the corner. his right hand sweeping along the floor struck something heavy lying there. his fingers closed over it; he raised it up, and hardly knowing what he did, crashed it against his enemy's head. he felt the tense muscles of the man relax, and then the weight of his inert body as it pressed down upon him. he wriggled free, and sprang to his feet. as he stood weak and trembling, looking down at the unconscious form of targo lying upon the floor, the girl suddenly ran over and stood beside him. her slim little body came only a little above his shoulder; instinctively he put his arm about her. a voice, calling from outside the room, made the girl look up into his face with new terror. "others are coming," she whispered tensely and huddled up against him. the very young man saw that the room had two doors--the one through which he had entered, and another in one of its other walls. there were no windows. he pulled the girl now towards the further door, but she held him back. "they come that way," she whispered. another voice sounded behind him and the very young man knew that a man was coming up along the passageway from the front entrance. targo's men! he remembered now the skulking figure he had seen outside the house. there were more than two, for now he heard other voices, and some one calling targo's name. he held the girl closer and stood motionless. like rats in a trap, he thought. he felt the fingers of his right hand holding something heavy. it was a piece of stone--the stone he had looked at through the microscope--the stone with which he had struck targo. he smiled to himself, and slipped it into his pocket. the girl had slowly pulled him over to the inner wall of the room. the footsteps came closer. they would be here in a moment. the very young man wondered how he should fight them all; then he thought of the knife that was still in the murdered man's body. he thought he ought to get it now while there was still time. he heard a click and the wall against which he and the girl were leaning yielded with their weight. a door swung open--a door the very young man had not seen before. the girl pulled him through the doorway, and swung the door softly closed behind them. the very young man found himself now in a long, narrow room with a very high ceiling. it had, apparently, no other door, and no windows. it was evidently a storeroom--piled high with what looked like boxes, and with bales of silks and other fabrics. the very young man looked around him hastily. then he let go of the girl, and, since locks were unknown in this world, began piling as many heavy objects as possible against the door. the girl tried to help him, but he pushed her away. once he put his ear to the door and listened. he heard voices outside in the strange oroid tongue. the girl stood beside him. "they are lifting targo up. he speaks; he is not dead," she whispered. for several minutes they stood there listening. the voices continued in a low murmur. "they'll know we are in here," said the very young man finally, in an undertone. "is there any other way out of this room?" the girl shook her head. the very young man forgot the import of her answer, and suddenly found himself thinking she was the prettiest girl he had ever seen. she was hardly more than sixteen, with a slender, not yet matured, yet perfectly rounded little body. she wore, like lylda, a short blue silk tunic, with a golden cord crossing her breast and encircling her waist. her raven black hair hung in two twisted locks nearly to her knees. her skin was very white and, even more than lylda's, gleamed with iridescent color. "only this one door," said the girl. the words brought the very young man to himself with a start. no other way out of the room! he knew that targo and his men would force their way in very soon. he could not prevent them. but it would take time. the very young man remembered that now he had time to take the chemicals. he put his hand to his armpit and felt the pouch that held the drug. he wondered which to take. the ceiling was very high; but to fight in the narrow confines of such a room---- he led the girl over to a pile of cushions and sat down beside her. "listen," he said briefly. "we are going to take a medicine; it will make us very small. then we will hide from targo and his men till they are gone. this is not magic; it is science. do you understand?" "i understand," the girl answered readily. "one of the strangers you are--my brother's friend." "you will not be afraid to take the drug?" "no." but though she spoke confidently, she drew closer to him and shivered a little. the very young man handed her one of the tiny pellets. "just touch it to the tip of your tongue as i do," he said warningly. they took the drug. when it had ceased to act, they found themselves standing on the rough uneven stone surface that was the floor of the room. far overhead in the dim luminous blackness they could just make out the great arching ceiling, stretching away out of sight down the length of the room. beside them stood a tremendous shaggy pile of coarsely woven objects that were the silk pillows on which they had been sitting a moment before--pillows that seemed forty or fifty feet square now and loomed high above their heads. the very young man took the frightened girl by the hand and led her along the tremendous length of a pile of boxes, blocks long it seemed. these boxes, from their size, might have been rectangular, windowless houses, jammed closely together, and piled one upon the other up into the air almost out of sight. finally they came to a broad passageway between the boxes--a mere crack it would have been before. they turned into it, and, a few feet beyond, came to a larger square space with a box making a roof over it some twenty feet above their heads. from this retreat they could see the lower part of the door leading into the other room and could hear from beyond it a muffled roar--the voices of targo and his men. hardly were they hidden when the door opened a little. it struck against the bales the very young man had piled against it. for a moment it held, but with the united efforts of the men pushing from the other side, it slowly yielded and swung open. targo stepped into the room. to the very young man he seemed nearly a hundred feet high. only his feet and ankles were visible at first, from where the very young man was watching. three other men came with him. they stamped back and forth for a time, moving some of the bales and boxes. luckily they left undisturbed those nearest the fugitives; after a moment they left, leaving the door open. the very young man breathed a long sigh of relief. "gosh, i'm glad that's over." he spoke in a low tone, although the men in the other room seemed so far away they would hardly have heard him if he had shouted at the top of his voice. alone with the girl now in this great silent room, the very young man felt suddenly embarrassed. "i am one of your brother's friends," he said. "my name's jack; is yours aura?" "lylda's sister i am," she answered quietly. "my father told me about you----" then with a rush came the memory of her father's death, which the startling experiences of the past half-hour had made her forget. her big, soft eyes filled with tears and her lips quivered. involuntarily the very young man put his arm about her again and held her close to him. she was so little and frail--so pathetic and so wholly adorable. for a long time they sat in silence; then the girl gently drew away. at the doorway they stood and listened; targo and his followers were still in the adjoining room, talking earnestly. "loto they have captured," aura whispered suddenly. "others of targo's men have taken him--in a boat--to orlog. to-morrow they send a messenger to my brother to demand he give up these drugs--or loto they will kill." the very young man waited, breathless. suddenly he heard targo laugh--a cruel, cynical laugh. aura shuddered. "and when he has the drug, all of us will he kill. and all in the land too who will not do as he bids." the men were rising, evidently in preparation to leave. aura continued: "they go--now--to orlog--all but targo. a little way from here, up the lake shore, a boat is waiting. it will take them there fast." with a last look around, targo and his followers disappeared through the back door of the room. an outer door clanged noisily, and the very young man and aura were left alone in the house. reoh murdered, loto stolen! the very young man thought of lylda and wondered if anything could have happened to her. "did they speak of your sister?" he asked. "targo said--he--he would put her to death," aura answered with a shudder. "he said--she killed his brother to-day." she turned to the very young man impulsively, putting her little hands up on his shoulders. "oh, my friend," she exclaimed. "you can do something to save my family? targo is so strong, so cruel. my father----" she stopped, and choked back a sob. "did they say where lylda was now?" "they did not know. she grew very big and went away." "where is your brother and my two friends?" "targo said they were here when he--he took loto. now they have gone home. he was afraid of them--now--because they have the drugs." "to-morrow they are going to send a messenger from orlog to demand the drugs?" "he said to-morrow. oh, you will do something for us? you can save loto?" the very young man was beginning to formulate a plan. "and to-night," he asked, "from what they said--are you sure they will not hurt loto?" "they said no. but he is so little--so----" the girl burst into tears, and at every sob the very young man's heart leaped in his breast. he wanted to comfort her, but he could think of no word to say; he wanted to help her--to do the best thing in what he saw was a grave crisis. what he should have done was to have taken her back to the chemist and his friends, and then with them planned the rescue of loto. but with the girl's hands upon his shoulders, and her sorrowful little tear-stained face looking up to his, he did not think of that. he thought only of her and her pathetic appeal. "you will do something, my friend? you can save loto?" he could save loto! with the power of the drugs he could do anything! the very young man made a sudden decision. "i don't know the way to orlog; you do?" he asked abruptly. "oh yes, i know it well." "we will go to orlog, you and i--now, and rescue loto. you will not be afraid?" the girl's eyes looked into his with a clear, steady gaze. the very young man stared down into their depths with his heart pounding. "i shall not be afraid--with you," said the girl softly. the very young man drew a long breath. he knew he must think it all out carefully. the drug would make them very large, and in a short time they could walk to orlog. no harm could come to them. once in orlog they would find loto--probably in targo's palace--and bring him back with them. the very young man pictured the surprise and gratification of the chemist and his friends. lylda would be back by then; no sooner would she have heard of loto's loss than he would bring him back to her. or perhaps they would meet lylda and she would join them. the very young man produced the drug and was about to give aura one of the pellets when another thought occurred to him. targo would not harm loto now because he was valuable as a hostage. but suppose he saw these two giants coming to the rescue? the very young man knew that probably the boy would be killed before he could save him. that way would not do. he would have to get to orlog unseen--rescue loto by a sudden rush, before they could harm him. but first it would be necessary for him and aura to get out of arite quietly without causing any excitement. once in the open country they could grow larger and travel rapidly to orlog. the very young man thought it would be best to be normal size while leaving arite. he explained his plan to aura briefly. it took several successive tastes of the different drugs before this result was accomplished, but in perhaps half an hour they were ready to leave the house. to the very young man this change of size was no longer even startling. aura, this time, with him beside her, seemed quite unafraid. "now we're ready," said the very young man, in a matter-of-fact tone that was far from indicating his true feeling. "take the way where we are least likely to be noticed--towards orlog. when we get in the open country we can get bigger." he led the girl across reoh's study. she kept her face averted as they passed the body lying on the floor, and in a moment they were outside the house. they walked rapidly, keeping close to the walls of the houses. the streets were nearly deserted and no one seemed to notice them. the very young man was calculating the time. "probably they are just getting to orlog with loto," he said. "once we get out of arite we'll travel fast; we'll have him back in two or three hours." aura said nothing, but walked beside him. once or twice she looked back over her shoulder. they were in the outskirts of the city, when suddenly the girl gripped her companion by the arm. "some one--behind us," she whispered. the very young man resisted an impulse to look around. they had come to a cross street; the very young man abruptly turned the corner, and clutching aura by the hand ran swiftly forward a short distance. when they had slowed down to a walk again the very young man looked cautiously back over his shoulder. as he did so he caught a glimpse of three men who had just reached the corner, and who darted hastily back out of sight as he turned his head. chapter xxviii the attack on the palace oteo led the two men swiftly through the city towards reoh's house. there were few pedestrians about and no one seemed particularly to notice them. yet somehow, the big business man thought, there hung about the city an ominous air of unrest. perhaps it was the abnormal quiet--that solemn sinister look of deserted streets; or perhaps it was an occasional face peering at them from a window, or a figure lurking in a doorway disappearing at their approach. the big business man found his heart beating fast. he suddenly felt very much alone. the realization came to him that he was in a strange world, surrounded by beings of another race, most of whom, he knew now, hated and feared him and those who had come with him. then his thoughts took another turn. he looked up at the brilliant galaxy of stars overhead. new, unexplored worlds! thousands, millions of them! in one tiny, little atom of a woman's wedding-ring! then he thought of his friend the banker. perhaps the ring had not been moved from its place in the clubroom. then--he looked at the sky again--then broadway--only thirty feet away from him this moment! he smiled a little at this conception, and drew a long breath--awed by his thoughts. oteo was plucking at his sleeve and pointing. across the street stood reoh's house. the doctor knocked upon its partially open front door, and, receiving no answer, they entered silently, with the dread sense of impending evil hanging over them. the doctor led the way into the old man's study. at the threshold he stopped, shocked into immobility. upon the floor, with the knife still in it, lay reoh's body. the doctor made a hasty examination, although the presence of the knife obviously made it unnecessary. a hurried search of the house convinced them that aura and the very young man were not there. the two men, confused by this double disaster, were at a loss to know what to do. "they've got him," said the big business man with conviction. "and the girl too, probably. he must have come back just as they were killing reoh." "there wasn't much time," the doctor said. "he was back here in ten minutes. but they've got him--you're right--or he would have been back with us before this." "they'll take him and the girl to orlog. they won't hurt them because they----" the big business man stopped abruptly; his face went white. "good god, frank, do you realize? they've got the drugs now!" targo had the drugs! the big business man shuddered with fear at the thought. their situation would be desperate, indeed, if that were so. the doctor reasoned it out more calmly. "i hadn't thought of that," he said slowly. "and it makes me think perhaps they have not captured jack. if they had the drugs they would lose no time in using them. they haven't used them yet--that's evident." the big business man was about to reply when there came a shouting from the street outside, and the sound of many feet rushing past the house. they hurried to the door. a mob swept by--a mob of nearly a thousand persons. most of them were men. some were armed with swords; others brandished huge stones or lengths of beaten gold implements, perhaps with which they had been working, and which now they held as weapons. the mob ran swiftly, with vainglorious shouts from its leaders. it turned a corner nearby and disappeared. from every house now people appeared, and soon the streets were full of scurrying pedestrians. most of them followed the direction taken by the mob. the listeners in the doorway could hear now, from far away, the sound of shouts and cheering. and from all around them came the buzz and hum of busy streets. the city was thoroughly awake--alert and expectant. the big business man flung the door wide. "i'm going to follow that crowd. see what's going on. we can't stay here in the midst of this." the doctor and oteo followed him out into the street, and they mingled with the hastening crowd. in their excitement they walked freely among the people. no one appeared to notice them, for the crowd was as excited as they, hurrying along, heedless of its immediate surroundings. as they advanced, the street became more congested. down another street they saw fighting going on--a weaponless crowd swaying and struggling aimlessly. a number of armed men charged this crowd--men who by their breastplates and swords the big business man recognized as the police. the crowd ceased struggling and dispersed, only to gather again in another place. the city was in a turmoil of excitement without apparent reason, or definite object. yet there was a steady tide in the direction the first armed mob had gone, and with that tide went the big business man and his two companions. after a time they came to an open park, beyond which, on a prominence, with the lake behind, stood a large building that the chemist had already pointed out to them as the king's palace. oteo led them swiftly into a side street to avoid the dense crowd around the park. making a slight detour they came back to it again--much nearer the palace now--and approached from behind a house that fronted the open space near the palace. "friend of the master--his house!" oteo explained as he knocked peremptorily at a side door. they waited a moment, but no one came. oteo pushed the door and led them within. the house was deserted, and following oteo, they went to the roof. here they could see perfectly what was going on around the palace, and in the park below them. this park was nearly triangular in shape--a thousand feet possibly on each side. at the base of the triangle, on a bluff with the lake behind it, stood the palace. its main entrance, two huge golden doors, stood at the top of a broad flight of stone steps. on these steps a fight was in progress. a mob surged up them, repulsed at the top by a score or more of men armed with swords, who were defending the doorway. the square was thronged with people watching the palace steps and shouting almost continuously. the fight before the palace evidently had been in progress for some time. many dead were lying in the doorway and on the steps below it. the few defenders had so far resisted successfully against tremendous odds, for the invaders, pressed upward by those behind, could not retreat, and were being killed at the top from lack of space in which to fight. "look there," cried the big business man suddenly. coming down a cross street, marching in orderly array with its commander in front, was a company of soldier police. it came to a halt almost directly beneath the watchers on the roof-tops, and its leader brandishing his sword after a moment of hesitation, ordered his men to charge the crowd. they did not move at the order, but stood sullenly in their places. again he ordered them forward, and, as they refused to obey, made a threatening move towards them. in sudden frenzy, those nearest leaped upon him, and in an instant he lay dead upon the ground, with half a dozen swords run through his body. then the men stood, in formation still, apathetically watching the events that were going on around them. meanwhile the fight on the palace steps raged more furiously than ever. the defenders were reduced now to a mere handful. "a moment more--they'll be in," said the doctor breathlessly. hardly had he spoken when, with a sudden, irresistible rush, the last of the guards were swept away, and the invaders surged through the doorway into the palace. a great cry went up from the crowd in the park as the palace was taken--a cry of applause mingled with awe, for they were a little frightened at what they were seeing. perhaps a hundred people crowded through the doorway into the palace; the others stood outside--on the steps and on the terrace below--waiting. hardly more than five minutes went by when a man appeared on the palace roof. he advanced to the parapet with several others standing respectfully behind him. "targo!" murmured oteo. it was targo--targo triumphantly standing with uplifted arms before the people he was to rule. when the din that was raised at his appearance had subsided a little he spoke; one short sentence, and then he paused. there was a moment of indecision in the crowd before it broke into tumultuous cheers. "the king--he killed," oteo said softly, looking at his master's friends with big, frightened eyes. the big business man stared out over the waving, cheering throng, with the huge, dominant, triumphant figure of targo above and muttered to himself, "the king is dead; long live the king." when he could make himself heard, targo spoke again. the doctor and the big business man were leaning over the parapet watching the scene, when suddenly a stone flew up from the crowd beneath, and struck the railing within a few feet of where they were standing. they glanced down in surprise, and realized, from the faces that were upturned, that they were recognized. a murmur ran over the crowd directly below, and then someone raised a shout. four words it seemed to be, repeated over and over. gradually the shout spread--"death to the giants," the big business man knew it was--"death to the giants," until the whole mass of people were calling it rhythmically--drowning out targo's voice completely. a thousand faces now stared up at the men on the roof-top and a rain of stones began falling around them. the doctor clutched his friend by the arm and pulled him back from the parapet. "they know us--good god, don't you see?" he said tensely. "come on. we must get out of this. there'll be trouble." he started across the roof towards the opening that led down into the house. the big business man jerked himself free from the grasp that held him. "i do see," he cried a little wildly. "i do see we've been damn fools. there'll be trouble. you're right--there will be trouble; but it won't be ours. i'm through--through with this miserable little atom and its swarm of insects." he gripped the doctor by both shoulders. "my god, frank, can't you understand? we're men, you and i--men! these creatures"--he waved his arm back towards the city--"nothing but insects--infinitesimal--smaller than the smallest thing we ever dreamed of. and we take them seriously. don't you understand? seriously! god, man, that's funny, not tragic." he fumbled at the neck of his robe, and tearing it away, brought out a vial of the drugs. "here," he exclaimed, and offered one of the pellets. "not too much," warned the doctor vehemently, "only touch it to your tongue." oteo, with pleading eyes, watched them taking the drug, and the doctor handed him a pellet, showing him how to take it. as they stood together upon the roof-top, clinging to one another, the city dwindled away rapidly beneath them. by the time the drug had ceased to act there was hardly room for them to stand on the roof, and the house, had it not been built solidly of stone, would have been crushed under their weight. at first they felt a little dizzy, as though they were hanging in mid-air, or were in a balloon, looking down at the city. then gradually, they seemed to be of normal size again, balancing themselves awkwardly upon a little toy-house whose top was hardly bigger than their feet. the park, only a step now beneath the house-top, swarmed with tiny figures less than two inches in height. targo still stood upon the palace roof; they could have reached down and picked him up between thumb and forefinger. the whole city lay within a radius of a few hundred feet around them. when they had stopped increasing in size, they leaped in turn over the palace, landing upon the broad beach of the lake. then they began walking along it. there was only room for one on the sand, and the other two, for they walked abreast, waded ankle-deep in the water. from the little city below them they could hear the hum of a myriad of tiny voices--thin, shrill and faint. suddenly the big business man laughed. there was no hysteria in his voice now--just amusement and relief. "and we took that seriously," he said. "funny, isn't it?" chapter xxix on the lake "you're right--we are being followed," the very young man said soberly. he had pulled the girl over close against the wall of a house. "did you see that?" "three, they are," aura answered. "i saw them before--in the street below--targo's men." evidently the three men had been watching the house from which they had come and had followed them from there. if they were targo's men, as seemed very probable, the very young man could not understand why they had not already attacked him. perhaps they intended to as soon as he and aura had reached a more secluded part of the city. they must know he had the drugs, and to gain possession of those certainly was what they were striving for. the very young man realized he must take no chances; to lose the drugs would be fatal to them all. "are we near the edge of the city?" he asked. "yes, very near." "then we shall get large here. if we make a run for it we will be in the country before we are big enough to attract too much attention. understand, aura?" "i understand." "we mustn't stir up the city if we can help it; with giants running around, the people would get worked up to a frenzy. you could see that with lylda this afternoon. not that you can blame them altogether, but we want to get loto back before we start anything here in arite." he took the pellets out as he spoke, and they each touched one of them to the tip of their tongues. "now, then, come on--not too fast, we want to keep going," said the very young man, taking the girl by the hand again. as they started off, running slowly down the street, the very young man looked back. the three men were running after them--not fast, seeming content merely to keep their distance. the very young man laughed. "wait till they see us get big. fine chance they've got." aura, her lithe, young body in perfect condition, ran lightly and easily as a fawn. she made a pretty picture as she ran, with her long, black hair streaming out behind her, and the short silk tunic flapping about her lean, round thighs. she still held the very young man by the hand, running just in advance of him, guiding him through the streets, which in this part of the city were more broken up and irregular. they had not gone more than a hundred yards when the pavement began to move unsteadily under them, as the deck of a plunging ship feels to one who runs its length, and the houses they were swiftly passing began visibly to decrease in size. the very young man felt the girl falter in her stride. he dropped her hand and slipped his arm about her waist, holding her other hand against it. she smiled up into his eyes, and thus they ran on, side by side. a few moments more and they were in the open country, running on a road that wound through the hills, between cultivated fields dotted here and there with houses. the landscape dwindled beneath them steadily, until they seemed to be running along a narrow, curving path, bordered by little patches of different-colored ground, like a checkerboard. the houses they passed now hardly reached as high as their knees. sometimes peasants stood in the doorways of these houses watching them in terror. occasionally they passed a farmer ploughing his field, who stopped his work, stricken dumb, and stared at them as they went swiftly by. when they were well out into the country, perhaps a quarter of the way to orlog--for to beings so huge as they the distance was not great--the very young man slowed down to a walk. "how far have we gone?" he asked. aura stopped abruptly and looked around her. they seemed now to be at the bottom of a huge, circular, shallow bowl. in every direction from where they stood the land curved upward towards the rim of the bowl that was the horizon--a line, not sharp and well defined, but dim and hazy, melting away into the blackness of the star-studded sky. behind them, hardly more than a mile away, according to their present stature--they had stopped growing entirely now--lay the city of arite. they could see completely across it and out into the country beyond. the lake, with whose shore they had been running parallel, was much closer to them. ahead, up near the rim of the horizon, lay a black smudge. aura pointed. "orlog is there," she said. "you see it?" to the very young man suddenly came the realization that already he was facing the problem of how to get into orlog unheralded. if they remained in their present size they could easily walk there in an hour or less. but long before that they would be seen and recognized. the very young man feared for loto's safety if he allowed that to happen. he seemed to be able to make out the city of orlog now. it was smaller than arite, and lay partially behind a hill, with most of its houses strung along the lake shore. if only they were not so tall they could not be seen so readily. but if they became smaller it would take them much longer to get there. and eventually they would have to become normal oroid size, or even smaller, in order to get into the city unnoticed. the very young man thought of the lake. perhaps that would be the best way. "can you swim?" he asked. and aura, with her ready smile, answered that she could. "if we are in the water," she added, seeming to have followed his thoughts, "they would not see us. i can swim very far--can you?" the very young man nodded. "if we could get near to orlog in the water," he said, "we might get a boat. and then when we were small, we could sail up. they wouldn't see us then." "there are many boats," answered the girl in agreement. "look!" there were, indeed, on the lake, within sight of them now, several boats. "we must get the one nearest orlog," the very young man said. "or else it will beat us in and carry the news." in a few minutes more they were at the lake shore. the very young man wore, underneath his robe, a close-fitting knitted garment very much like a bathing-suit. he took off his robe now, and rolling it up, tied it across his back with the cord he had worn around his waist. aura's tunic was too short to impede her swimming and when the very young man was ready, they waded out into the water together. they found the lake no deeper than to aura's shoulders, but as it was easier to swim than to wade, they began swimming--away from shore towards the farthest boat that evidently was headed for orlog. the very young man thought with satisfaction that, with only their heads visible, huge as they would appear, they could probably reach this boat without being seen by any one in orlog. the boat was perhaps a quarter of a mile from them--a tiny little toy vessel, it seemed, that they never would have seen except for its sail. they came up to it rapidly, for they were swimming very much faster than it could sail, passing close to one of the others and nearly swamping it by the waves they made. as they neared the boat they were pursuing--it was different from any the very young man had seen so far, a single, canoe-shaped hull, with out-riders on both sides--they could see it held but a single occupant, a man who sat in its stern--a figure about as long as one of the very young man's fingers. the very young man and aura were swimming side by side, now. the water was perfect in temperature--neither too hot nor too cold; they had not been swimming fast, and were not winded. "we've got him, what'll we do with him," the very young man wanted to know in dismay, as the thought occurred to him. he might have been more puzzled at how to take the drug to make them smaller while they were swimming, but aura's answer solved both problems. "there is an island," she said flinging an arm up out of the water. "we can push the boat to it, and him we can leave there. is that not the thing to do?" "you bet your life," the very young man agreed, enthusiastically. "that's just the thing to do." as they came within reach of the boat the very young man stopped swimming and found that the water was not much deeper than his waist. the man in the boat appeared now about to throw himself into the lake from fright. "tell him, aura," the very young man said. "we won't hurt him." wading through the water, they pushed the boat with its terrified occupant carefully in front of them towards the island, which was not more than two or three hundred yards away. the very young man found this rather slow work; becoming impatient, he seized the boat in his hand, pinning the man against its seat with his forefinger so he would not fall out. then raising the boat out of the water over his head he waded forward much more rapidly. the island, which they reached in a few moments more, was circular in shape, and about fifty feet in diameter. it had a beach entirely around it; a hill perhaps ten feet high rose near its center, and at one end it was heavily wooded. there were no houses to be seen. the very young man set the boat back on the water, and they pushed it up on the beach. when it grounded the tiny man leaped out and ran swiftly along the sand. the very young man and aura laughed heartily as they stood ankle-deep in the water beside the boat, watching him. for nearly five minutes he ran; then suddenly he ducked inland and disappeared in the woods. when they were left alone they lost no time in becoming normal oroid size. the boat now appeared about twenty-five feet long--a narrow, canoe-shaped hull hollowed out of a tree-trunk. they climbed into it, and with a long pole they found lying in its bottom, the very young man shoved it off the beach. chapter xxx word music the boat had a mast stepped near the bow, and a triangular cloth sail. the very young man sat in the stern, steering with a short, broad-bladed paddle; aura lay on a pile of rushes in the bottom of the boat, looking up at him. for about half a mile the very young man sailed along parallel with the beach, looking for the man they had marooned. he was nowhere in sight, and they finally headed out into the lake towards orlog, which they could just see dimly on the further shore. the breeze was fresh, and they made good time. the boat steered easily, and the very young man, reclining on one elbow, with aura at his feet, felt at peace with himself and with the world. again he thought this girl the prettiest he had ever seen. there was something, too, of a spiritual quality in the delicate smallness of her features--a sweetness of expression in her quick, understanding smile, and an honest clearness in her steady gaze that somehow he seemed never to have seen in a girl's face before. he felt again, now that he had time to think more of her, that same old diffidence that had come to him before when they were alone in the storeroom of her home. that she did not share this feeling was obvious from the frankness and ease of her manner. for some time after leaving the island neither spoke. the very young man felt the girl's eyes fixed almost constantly upon him--a calm gaze that held in it a great curiosity and wonderment. he steered steadily onward towards orlog. there was, for the moment, nothing to discuss concerning their adventure, and he wondered what he should say to this girl who stared at him so frankly. then he met her eyes, and again she smiled with that perfect sense of comradeship he had so seldom felt with women of his own race. "you're very beautiful," said the very young man abruptly. the girl's eyes widened a little, but she did not drop her lashes. "i want to be beautiful; if you think it is so, i am very glad." "i do. i think you're the prettiest girl i ever saw." he blurted out the words impetuously. he was very earnest, very sincere, and very young. a trace of coquetry came into the girl's manner. "prettier than the girls of your world? are they not pretty?" "oh, yes--of course; but----" "what?" she asked when he paused. the very young man considered a moment. "you're--you're different," he said finally. she waited. "you--you don't know how to flirt, for one thing." the girl turned her head away and looked at him a little sidewise through lowered lashes. "how do you know that?" she asked demurely; and the very young man admitted to himself with a shock of surprise that he certainly was totally wrong in that deduction at least. "tell me of the girls in your world," she went on after a moment's silence. "my sister's husband many times he has told me of the wonderful things up there in that great land. but more i would like to hear." he told her, with an eloquence and enthusiasm born of youth, about his own life and those of his people. she questioned eagerly and with an intelligence that surprised him, for she knew far more of the subject than he realized. "these girls of your country," she interrupted him once. "they, too, are very beautiful; they wear fine clothes--i know--my brother he has told me." "yes," said the very young man. "and are they very learned--very clever--do they work and govern, like the men?" "some are very learned. and they are beginning to govern, like the men; but not so much as you do here." the girl's forehead wrinkled. "my brother he once told me," she said slowly, "that in your world many women are bad. is that so?" "some are, of course. and some men think that most are. but i don't; i think women are splendid." "if that is so, then better i can understand what i have heard," the girl answered thoughtfully. "if oroid women were as i have heard my brother talk of some of yours, this world of ours would soon be full of evil." "you are different," the very young man said quickly. "you--and lylda." "the women here, they have kept the evil out of life," the girl went on. "it is their duty--their responsibility to their race. your good women--they have not always governed as we have. why is that?" "i do not know," the very young man admitted. "except because the men would not let them." "why not, if they are just as learned as the men?" the girl was smiling--a little roguish, twisted smile. "there are very clever girls," the very young man went on hastily; he found himself a little on the defensive, and he did not know just why. "they are able to do things in the world. but--many men do not like them." aura was smiling openly now, and her eyes twinkled with mischief. "perhaps it is the men are jealous. could that not be so?" the very young man did not answer, and the girl went on more seriously. "the women of my race, they are very just. perhaps you know that, jack. often has my brother told us of his own great world and of its problems. and the many things he has told us--lylda and i--we have often wondered. for every question has its other side, and we cannot judge--from him alone." the very young man, surprised at the turn their conversation had taken, and confused a little by this calm logic from a girl--particularly from so young and pretty a girl--was at a loss how to go on. "you cannot understand, aura," he finally said seriously. "women may be all kinds; some are bad--some are good. down here i know it is not that way. sometimes when a girl is smart she thinks she is smarter than any living man. you would not like that sort of girl would you?" "my brother never said it just that way," she answered with equal seriousness. "no, that would be bad--very bad. in our land women are only different from men. they know they are not better or worse--only different." the very young man was thinking of a girl he once knew. "i hate clever girls," he blurted out. aura's eyes were teasing him again. "i am so sorry," she said sadly. the very young man looked his surprise. "why are you sorry?" "my sister, she once told me i was clever. my brother said it, too, and i believed them." the very young man flushed. "you're different," he repeated. "how--different?" she was looking at him sidewise again. "i don't know; i've been trying to think--but you are. and i don't hate you--i like you--very, very much." "i like you, too," she answered frankly, and the very young man thought of loto as she said it. he was leaning down towards her, and their hands met for an instant. the very young man had spread his robe out to dry when he first got into the boat, and now he put it on while aura steered. then he sat beside her on the seat, taking the paddle again. "do you go often to the theater?" she asked after a time. "oh, yes, often." "nothing like that do we have here," she added, a little wistfully. "only once, when we played a game in the field beyond my brother's home. lylda was the queen and i her lady. and do you go to the opera, too? my brother he has told me of the opera. how wonderful must that be! so beautiful--more beautiful even it must be than lylda's music. but never shall it be for me." she smiled sadly: "never shall i be able to hear it." an eager contradiction sprang to the very young man's lips, but the girl shook her head quietly. for several minutes they did not speak. the wind behind them blew the girl's long hair forward over her shoulders. a lock of it fell upon the very young man's hand as it lay on the seat between them, and unseen he twisted it about his fingers. the wind against his neck felt warm and pleasant; the murmur of the water flowing past sounded low and sweet and soothing. overhead the stars hung very big and bright. it was like sailing on a perfect night in his own world. he was very conscious of the girl's nearness now--conscious of the clinging softness of her hair about his fingers. and all at once he found himself softly quoting some half-forgotten lines: "if i were king, ah, love! if i were king what tributary nations i would bring to bow before your scepter and to swear allegiance to your lips and eyes and hair." aura's questioning glance of surprise brought him to himself. "that is so pretty--what is that?" she asked eagerly. "never have i heard one speak like that before." "why, that's poetry; haven't you ever heard any poetry?" the girl shook her head. "it's just like music--it sings. do it again." the very young man suddenly felt very self-conscious. "do it again--please." she looked pleadingly up into his face and the very young man went on: "beneath your feet what treasures i would fling! the stars would be your pearls upon a string; the world a ruby for your finger-ring; and you could have the sun and moon to wear if i were king." the girl clapped her hands artlessly. "oh, that is so pretty. never did i know that words could sound like that. say it some more, please." and the very young man, sitting under the stars beside this beautiful little creature of another world, searched into his memory and for her who never before had known that words could rhyme, opened up the realm of poetry. chapter xxxi the palace of orlog engrossed with each other the very young man and aura sailed close up to the water-front of orlog before they remembered their situation. it was the very young man who first became aware of the danger. without explanation he suddenly pulled aura into the bottom of the boat, leaving it to flutter up into the wind unguided. "they might see us from here," he said hurriedly. "we must decide what is best for us to do now." they were then less than a quarter of a mile from the stone quay that marked the city's principal landing-place. nearer to them was a broad, sandy beach behind which, in a long string along the lake shore, lay the city. its houses were not unlike those of arite, although most of them were rather smaller and less pretentious. on a rise of ground just beyond the beach, and nearly in front of them, stood an elaborate building that was targo's palace. "we daren't go much closer," the very young man said. "they'd recognize us." "you they would know for one of the strangers," said aura. "but if i should steer and you were hidden no one would notice." the very young man realized a difficulty. "we've got to be very small when we go into the city." "how small would you think?" asked aura. the very young man held his hands about a foot apart. "you see, the trouble is, we must be small enough to get around without too much danger of being seen; but if we get too small it would be a terrible walk up there to targo's palace." "we cannot sail this boat if we are such a size," aura declared. "too large it would be for us to steer." "that's just it, but we can't go any closer this way." aura thought a moment. "if you lie there," she indicated the bottom of the boat under a forward seat, "no one can see. and i will steer--there to the beach ahead; me they will not notice. then at the beach we will take the drug." "we've got to take a chance," said the very young man. "some one may come along and see us getting small." they talked it over very carefully for some time. finally they decided to follow aura's plan and run the boat to the beach under her guidance; then to take the drug. there were few people around the lake front at this hour; the beach itself, as far as they could see, was entirely deserted, and the danger of discovery seemed slight. aura pointed out, however, that once on shore, if their stature were so great as a foot they would be even more conspicuous than when of normal size even allowing for the strangeness of the very young man's appearance. the very young man made a calculation and reached the conclusion that with a height of six or seven inches they would have to walk about a mile from the landing-place to reach targo's palace. they decided to become as near that size as they conveniently could. when both fully understood what they intended to do, the very young man gave aura one of the pellets of the drug and lay down in the bow of the boat. without a word the girl took her seat in the stern and steered for the beach. when they were close inshore aura signalled her companion and at the same moment both took the drug. then she left her seat and lay down beside the very young man. the boat, from the momentum it had gained, floated inshore and grounded gently on the beach. as they lay there, the very young man could see the sides of the boat growing up steadily above their heads. the gunwale was nearly six feet above them before he realized a new danger. scrambling to his feet he pulled the girl up with him; even when standing upright their heads came below the sides of the vessel. "we've got to get out right now," the very young man said in an excited whisper. "we'd be too small." he led the girl hastily into the bow and with a running leap clambered up and sat astride the gunwale. then, reaching down he pulled aura up beside him. in a moment they had dropped overboard up to their shoulders in the water. high overhead loomed the hull of the boat--a large sailing vessel it seemed to them now. they started wading towards shore immediately, but, because they were so rapidly diminishing in size, it was nearly five minutes before they could get there. once on shore they lay prone upon the sand, waiting for the drug to cease its action. when, by proper administering of both chemicals, they had reached approximately their predetermined stature, which, in itself, required considerable calculation on the very young man's part, they stood up near the water's edge and looked about them. the beach to them now, with its coarse-grained sand, seemed nearly a quarter of a mile wide; in length it extended as far as they could see in both directions. beyond the beach, directly in front of them on a hill perhaps a thousand feet above the lake level, and about a mile or more away, stood targo's palace. to the very young man it looked far larger than any building he had ever seen. the boat in which they had landed lay on the water with its bow on the beach beside them. it was now a vessel some two hundred and fifty feet in length, with sides twenty feet high and a mast towering over a hundred feet in the air. there was no one in sight from where they stood. "come on, aura," said the very young man, and started off across the beach towards the hill. it was a long walk through the heavy sand to the foot of the hill. when they arrived they found themselves at the beginning of a broad stone roadway--only a path to those of normal oroid size--that wound back and forth up the hill to the palace. they walked up this road, and as they progressed, saw that it was laid through a grassy lawn that covered the entire hillside--a lawn with gray-blue blades of grass half as high as their bodies. after walking about ten minutes they came to a short flight of steps. each step was twice as high as their heads--impossible of ascent--so they made a detour through the grass. suddenly aura clutched the very young man by the arm with a whispered exclamation, and they both dropped to the ground. a man was coming down the roadway; he was just above the steps when they first saw him--a man so tall that, standing beside him, they would have reached hardly above his ankles. the long grass in which they were lying hid them effectually from his sight and he passed them by unnoticed. when he was gone the very young man drew a long breath. "we must watch that," he said apprehensively. "if any one sees us now it's all off. we must be extremely careful." it took the two adventurers over an hour to get safely up the hill and into the palace. its main entrance, approached by a long flight of steps, was an impossible means of ingress, but aura fortunately knew of a smaller door at the side which led into the basement of the building. this door they found slightly ajar. it was open so little, however, that they could not get past, and as they were not strong enough even with their combined efforts, to swing the door open, they were again brought to a halt. "we'd better get still smaller," the very young man whispered somewhat nervously. "there's less danger that way." they reduced their size, perhaps one half, and when that was accomplished the crack in the door had widened sufficiently to let them in. within the building they found themselves in a hallway several hundred feet wide and half a mile or more in length--its ceiling high as the roof of some great auditorium. the very young man looked about in dismay. "great scott," he ejaculated, "this won't do at all." "many times i have been here," said aura. "it looks so very different now, but i think i know the way." "that may be," agreed the very young man dubiously, "but we'd have to walk miles if we stay as small as this." a heavy tread sounded far away in the distance. the very young man and aura shrank back against the wall, close by the door. in a moment a man's feet and the lower part of his legs came into view. he stopped by the door, pulling it inward. the very young man looked up into the air; a hundred and fifty feet, perhaps, above their heads he saw the man's face looking out through the doorway. in a moment another man joined him, coming from outside, and they spoke together for a time. their roaring voices, coming down from this great height, were nevertheless distinctly audible. "in the audience room," aura whispered, after listening an instant, "targo's younger brother talks with his counsellors. big things they are planning." the very young man did not answer; the two men continued their brief conversation and parted. when the very young man and aura were left alone, he turned to the girl eagerly. "did they mention loto? is he here?" "of him they did not speak," aura answered. "it is best that we go to the audience room, where they are talking. then, perhaps, we will know." the very young man agreed, and they started off. for nearly half an hour they trudged onward along this seemingly endless hallway. then again they were confronted with a flight of steps--this time steps that were each more than three times their own height. "we've got to chance it," said the very young man, and after listening carefully and hearing no one about, they again took the drug, making themselves sufficiently large to ascend these steps to the upper story of the building. it was nearly an hour before the two intruders, after several narrow escapes from discovery, and by alternating doses of both drugs, succeeded in getting into the room where targo's brother and his advisers were in conference. they entered through the open door--a doorway so wide that a hundred like them could have marched through it abreast. a thousand feet away across the vastness of the room they could see targo's brother and ten of his men--sitting on mats upon the floor, talking earnestly. before them stood a stone bench on which were a number of golden goblets and plates of food. the adventurers ran swiftly down the length of the room, following its wall. it echoed with their footfalls, but they knew that this sound, so loud to their ears, would be inaudible to the huge figures they were approaching. "they won't see us," whispered the very young man, "let's get up close." and in a few moments more they were standing beside one of the figures, sheltered from sight by a corner of the mat upon which the man was sitting. his foot, bent sidewise under him upon the floor, was almost within reach of the very young man's hand. the fibre thong that fastened its sandal looked like a huge rope thick as the very young man's ankle, and each of its toes were half as long as his entire body. targo's brother, a younger man than those with him, appeared to be doing most of the talking. he it was beside whom aura and the very young man were standing. "you tell me if they mention loto," whispered the very young man. aura nodded and they stood silent, listening. the men all appeared deeply engrossed with what their leader was saying. the very young man, watching his companion's face, saw an expression of concern and fear upon it. she leaned towards him. "in arite, to-night," she whispered, "targo is organizing men to attack the palace of the king. him will they kill--then targo will be proclaimed leader of all the oroid nation." "we must get back," the very young man answered in an anxious whisper. "i wish we knew where loto was; haven't they mentioned him--or any of us?" aura did not reply, and the very young man waited silent. once one of the men laughed--a laugh that drifted out into the immense distances of the room in great waves of sound. aura gripped her companion by the arm. "then when targo rules the land, they will send a messenger to my brother. him they will tell that the drugs must be given to targo, or loto will be killed--wait--when they have the drugs," aura translated in a swift, tense whisper, "then all of us they will kill." she shuddered. "and with the drugs they will rule as they desire--for evil." "they'll never get them," the very young man muttered. targo's brother leaned forward and raised a goblet from the table. the movement of his foot upon the floor made the two eavesdroppers jump aside to avoid being struck. again aura grasped her companion by the arm. "he is saying loto is upstairs," she whispered after a moment. "i know where." "i knew it," said the very young man exultingly. "you take us there. come on--let's get out of here--we mustn't waste a minute." they started back towards the wall nearest them--some fifty feet away--and following along its edge, ran down towards the doorway through which they had entered the room. they were still perhaps a hundred yards away from it, running swiftly, when there appeared in the doorway the feet and legs of two men who were coming in. the very young man and aura stopped abruptly, shrinking up against the side of the wall. then there came a heavy metallic clanging sound; the two men entered the room, closing the door. chapter xxxii an ant-hill outraged "we'll have to get smaller," said the doctor. "there's rogers' house." they had been walking along the beach from the king's palace hardly more than a hundred yards. the doctor and the big business man were in front, and oteo, wide-eyed and solemn, was close behind them. the doctor was pointing down at the ground a few feet ahead. there, at a height just above their ankles, stood the chemist's house--a little building whose roof did not reach more than half-way to their knees, even though it stood on higher ground than the beach upon which they were walking. on the roof they could see two tiny figures--the chemist and lylda--waving their arms. the big business man stopped short. "now see here, frank, let's understand this. we've been fooling with this thing too damned long. we've made a hell of a mess of it, you know that." he spoke determinedly, with a profanity unusual with him. the doctor did not answer. "we got here--yesterday. we found a peaceful world. dissatisfaction in it--yes. but certainly a more peaceful world than the one we left. we've been here one day--one day, frank, and now look at things. this child, loto--stolen. jack disappeared--god knows what's happened to him. a revolution--the whole place in an uproar. all in one day, since we took our place in this world and tried to mix up in its affairs. "it's time to call a halt, frank. if only we can get jack back. that's the bad part--we've got to find jack. and then get out; we don't belong here anyway. it's nothing to us--why, man, look at it." he waved his arm out over the city. in the street beside them they could see a number of little figures no bigger than their fingers, staring up into the air. "what is all that to us now, as we stand here. nothing. nothing but a kid's toy; with little animated mannikins for a child to play with." "we've got to find jack," said the doctor. "certainly we have--and then get out. we're only hurting these little creatures, anyway, by being here." "but there's rogers and lylda," added the doctor. "and loto and lylda's sister." "take them with us. they'll have to go--they can't stay here now. but we must find jack--that's the main thing." "look," the doctor said, moving forward. "they're shouting to us." they walked up and bent over the chemist's house. their friend was making a funnel of his hands and trying to attract their attention. the big business man knelt upon the beach and put his head down beside the house. "make yourselves smaller," he heard the chemist shouting in a shrill little voice. "we think it best not to. you must come up to us. serious things have happened. take the drug now--then we'll tell you." the big business man, with his knees upon the beach, had one hand on the sand and the other at the gate of lylda's garden. his face was just above the roof-top. the two little figures consulted a moment; then the chemist shouted up, "all right; wait," and he and lylda disappeared into the house. a moment afterwards they reappeared in the garden; eena was with them. they crossed the garden and turned into the street towards the flight of steps that led down to the lake. the big business man had regained his feet and was standing ankle-deep in the water talking to the doctor when oteo suddenly plucked at his sleeve. "the master--" he cried. the youth was staring down into the street, with a look of terror on his face. the big business man followed the direction of his glance; at the head of the steps a number of men had rushed upon the chemist and the two women, and were dragging them back up the hill. the big business man hesitated only a moment; then he reached down and plucking a little figure from one of the struggling groups, flung it back over his shoulder into the lake. the other assailants did not run, as he had expected, so he gently pried them apart with his fingers from their captives, and, one by one, flung them into the air behind him. one who struck lylda, he squashed upon the flagstones of the street with his thumb. only one escaped. he had been holding eena; when he saw he was the last, he suddenly dropped his captive and ran shrieking up the hill into the city. the big business man laughed grimly, and got upon his feet a little unsteadily. his face was white. "you see, frank," he said, and his voice trembled a little. "good god, suppose we had been that size, too." in a few moments more the chemist, lylda and eena had taken the drug and were as large as the others. all six stood in the water beside the chemist's house. the chemist had not spoken while he was growing; now he greeted his friends quietly. "a close call, gentlemen. i thank you." he smiled approvingly at the big business man. eena and oteo stood apart from the others. the girl was obviously terror-stricken by the experiences she had undergone. oteo put his arm across her shoulders, and spoke to her reassuringly. "where is jack?" lylda asked anxiously. "and my father--and aura?" the big business man thought her face looked years older than when he had last seen it. her expression was set and stern, but her eyes stared into his with a gentle, sorrowful gaze that belied the sternness of her lips. they told her, as gently as they could, of the death of her father and the disappearance of the very young man, presumably with aura. she bore up bravely under the news of her father's death, standing with her hand on her husband's arm, and her sorrowful eyes fixed upon the face of the big business man who haltingly told what had befallen them. when he came to a description of the attack on the palace, the death of the king, and the triumph of targo, the chemist raised his hands with a hopeless gesture. the doctor put in: "it's a serious situation--most serious." "there's only one thing we can do," the big business man added quickly. "we must find jack and your sister," he addressed lylda, whose eyes had never left his face, "and then get out of this world as quickly as we can--before we do it any more harm." the chemist began pacing up and down the strip of the beach. he had evidently reached the same conclusion--that it was hopeless to continue longer to cope with so desperate a situation. but he could not bring himself so easily to a realization that his life in this world, of which he had been so long virtually the leader, was at an end. he strode back and forth thinking deeply; the water that he kicked idly splashed up sometimes over the houses of the tiny city at his side. the big business man went on, "it's the only way--the best way for all of us and for this little world, too." "the best way for you--and you." lylda spoke softly and with a sweet, gentle sadness. "it is best for you, my friends. but for me----" she shook her head. the big business man laid his hands gently on her shoulders. "best for you, too, little woman. and for these people you love so well. believe me--it is." the chemist paused in his walk. "probably aura and jack are together. no harm has come to them so far--that's certain. if his situation were desperate he would have made himself as large as we are and we would see him." "if he got the chance," the doctor murmured. "certainly he has not been killed or captured," the chemist reasoned, "for we would have other giants to face immediately that happened." "perhaps he took the girl with him and started off to orlog to find loto," suggested the doctor. "that crazy boy might do anything." "he should be back by now, even if he had," said the big business man. "i don't see how anything could happen to him--having those----" he stopped abruptly. while they had been talking a crowd of little people had gathered in the city beside them--a crowd that thronged the street before the chemist's house, filled the open space across from it and overflowed down the steps leading to the beach. it was uncanny, standing there, to see these swarming little creatures, like ants whose hill had been desecrated by the foot of some stray passer-by. they were enraged, and with an ant's unreasoning, desperate courage they were ready to fight and to die, against an enemy irresistibly strong. "good god, look at them," murmured the big business man in awe. the steps leading to the beach were black with them now--a swaying, struggling mass of little human forms, men and women, hardly a finger's length in height, coming down in a steady stream and swarming out upon the beach. in a few moments the sand was black with them, and always more appeared in the city above to take their places. the big business man felt a sharp sting in his foot above the sandal. one of the tiny figures was clinging to its string and sticking a sword into his flesh. involuntarily he kicked; a hundred of the little creatures were swept aside, and when he put his foot back upon the sand he could feel them smash under his tread. their faint, shrill, squeaking shrieks had a ghostly semblance to human voices, and he turned suddenly sick and faint. then he glanced at lylda's face; it bore an expression of sorrow and of horror that made him shudder. to him at first these had been savage, vicious little insects, annoying, but harmless enough if one kept upon one's feet; but to her, he knew, they were men and women--misguided, frenzied--but human, thinking beings like herself. and he found himself wondering, vaguely, what he should do to repel them. the attack was so unexpected, and came so quickly that the giants had stood motionless, watching it with awe. before they realized their situation the sand was so crowded with the struggling little figures that none of them could stir without trampling upon scores. oteo and eena, standing ankle-deep in the water, were unattacked, and at a word from the chemist the others joined them, leaving little heaps of mangled human forms upon the beach where they had trod. all except lylda. she stood her ground--her face bloodless, her eyes filled with tears. her feet were covered now; her ankles bleeding from a dozen tiny knives hacking at her flesh. the chemist called her to him, but she only raised her arms with a gesture of appeal. "oh, my husband," she cried. "please, i must. let me take the drug now and grow small--like them. then will they see we mean them no harm. and i shall tell them we are their friends--and you, the master, mean only good----" the big business man started forward. "they'll kill her. god, that's----" but the chemist held them back. "not now, lylda," he said gently. "not now. don't you see? there's nothing you can do; it's too late now." he met her gaze unyielding. for a moment she stared; then her figure swayed and with a low sob she dropped in a heap upon the sand. as lylda fell, the chemist leaped forward, the other three men at his side. a strident cry came up from the swarming multitude, and in an instant hundreds of them were upon her, climbing over her and thrusting their swords into her body. the chemist and the big business man picked her up and carried her into the water, brushing off the fighting little figures that still clung to her. there they laid her down, her head supported by eena, who knelt in the water beside her mistress. the multitude on the sand crowded up to the water's edge; hundreds, forced forward by the pressure of those behind, plunged in, swam about, or sank and were rolled back by the surf, lifeless upon the shore. the beach crawled with their struggling forms, only the spot where lylda had fallen was black and still. "she's all right," said the doctor after a moment, bending over lylda. a cry from oteo made him straighten up quickly. out over the horizon, towards orlog, there appeared the dim shape of a gigantic human form, and behind it others, faint and blurred against the stars! chapter xxxiii the rescue of loto the very young man heard the clang of the closing door with sinking heart. the two newcomers, passing close to him and aura as they stood shrinking up against the wall, joined their friends at the table. the very young man turned to aura with a solemn face. "are there any other doors?" he asked. the girl pointed. "one other, there--but see, it, too, is closed." far across the room the very young man could make out a heavy metal door similar to that through which they had entered. it was closed--he could see that plainly. and to open it--so huge a door that its great golden handle hung nearly a hundred feet above them--was an utter impossibility. the very young man looked at the windows. there were four of them, all on one side of the room--enormous curtained apertures, two hundred feet in length and half as broad--but none came even within fifty feet of the floor. the very young man realized with dismay that there was apparently no way of escape out of the room. "we can't get out, aura," he said, and in spite of him his voice trembled. "there's no way." the girl had no answer but a quiet nod of agreement. her face was serious, but there was on it no sign of panic. the very young man hesitated a moment; then he started off down the room towards one of the doors, with aura close at his side. they could not get out in their present size, he knew. nor would they dare make themselves sufficiently large to open the door, or climb through one of the windows, even if the room had been nearer the ground than it actually was. long before they could escape they would be discovered and seized. the very young man tried to think it out clearly. he knew, except for a possible accident, or a miscalculation on his part, that they were in no real danger. but he did not want to make a false move, and now for the first time he realized his responsibility to aura, and began to regret the rashness of his undertaking. they could wait, of course, until the conference was over, and then slip out unnoticed. but the very young man felt that the chances of their rescuing loto were greater now than they would be probably at any time in the future. they must get out now, he was convinced of that. but how? they were at the door in a moment more. standing so close it seemed, now, a tremendous shaggy walling of shining metal. they walked its length, and then suddenly the very young man had an idea. he threw himself face down upon the floor. underneath the door's lower edge there was a tiny crack. to one of normal oroid size it would have been unnoticeable--a space hardly so great as the thickness of a thin sheet of paper. but the very young man could see it plainly; he gauged its size by slipping the edge of his robe into it. this crack was formed by the bottom of the door and the level surface of the floor; there was no sill. the door was perfectly hung, for the crack seemed to be of uniform size. the very young man showed it to aura. "there's the way out," he whispered. "through there and then large again on the other side." he made his calculation of size carefully, and then, crushing one of the pills into powder, divided a portion of it between himself and the girl. aura seemed tired and the drug made her very dizzy. they both sat upon the stone floor, close up to the door, and closed their eyes. when, by the feeling of the floor beneath them, they knew the action of the drug was over, they stood up unsteadily and looked around them. they now found themselves standing upon a great stone plain. the ground beneath their feet was rough, but as far away as they could see, out up to the horizon, it was mathematically level. this great expanse was empty except in one place; over to the right there appeared a huge, irregular, blurred mass that might have been, by its look, a range of mountains. but the mass moved as they stared at it, and the very young man knew it was the nearest one of targo's men, sitting beside the table. in the opposite direction, perhaps a hundred yards away from where they were standing, they could see the bottom of the door. it hung in the air some fifty feet above the surface of the ground. they walked over and stood underneath; like a great roof it spread over them--a flat, level surface parallel with the floor beneath. at this extraordinary change in their surroundings aura seemed frightened, but seeing the matter-of-fact way in which her companion acted, she maintained her composure and soon was much interested in this new aspect of things. the very young man took a last careful look around and then, holding aura by the hand, started to cross under the door in a direction he judged to be at right angles to its length. they walked swiftly, trying to keep their sense of direction, but having no means of knowing whether they were doing so or not. for perhaps ten minutes they walked; then they emerged on the other side of the door and again faced a great level, empty expanse. "we're under," the very young man remarked with relief. "do you know where loto is from here?" aura had recovered her self-possession sufficiently to smile. "i might, perhaps," she answered, with a pretty little shrug. "but it's a long way, don't you think? a hundred miles, it may be?" "we get large here," said the very young man, with an answering smile. he was greatly relieved to be outside the audience room; the way seemed easy before them now. they took the opposite drug, and after several successive changes of size, succeeded in locating the upper room in the palace in which loto was held. at this time they were about the same relative size to their enemies as when they entered the audience chamber on the floor below. "that must be it," the very young man whispered, as they cautiously turned a hallway corner. a short distance beyond, in front of a closed door, sat two guards. "that is the room of which they spoke," aura answered. "only one door there is, i think." "that's all right," said the very young man confidently. "we'll do the same thing--go under the door." they went close up to the guards, who were sitting upon the floor playing some sort of a game with little golden balls. this door, like the other, had a space beneath it, rather wider than the other, and in ten minutes more the very young man and aura were beneath it, and inside the room. as they grew larger again the very young man at first thought the room was empty. "there he is," cried aura happily. the very young man looked and could see across the still huge room, the figure of loto, standing at a window opening. "don't let him see us till we're his size," cautioned the very young man. "it might frighten him. and if he made any noise----" he looked at the door behind them significantly. aura nodded eagerly; her face was radiant. steadily larger they grew. loto did not turn round, but stood quiet, looking out of the window. they crept up close behind him, and when they were normal size aura whispered his name softly. the boy turned in surprise and she faced him with a warning finger on her lips. he gave a low, happy little cry, and in another instant was in her arms, sobbing as she held him close to her breast. the very young man's eyes grew moist as he watched them, and heard the soft oroid words of endearment they whispered to each other. he put his arms around them, too, and all at once he felt very big and very strong beside these two delicate, graceful little creatures of whom he was protector. a noise in the hallway outside brought the very young man to himself. "we must get out," he said swiftly. "there's no time to lose." he went to the window; it faced the city, fifty feet or more above the ground. the very young man make a quick decision. "if we go out the way we came, it will take a very long time," he explained. "and we might be seen. i think we'd better take the quick way; get big here--get right out," he waved his hands towards the roof, "and make a run for it back to arite." he made another calculation. the room in which they were was on the top floor of the palace; aura had told him that. it was a room about fifty feet in length, triangular in shape, and some thirty feet from floor to ceiling. the very young man estimated that when they had grown large enough to fill the room, they could burst through the palace roof and leap to the ground. then in a short time they could run over the country, back to arite. he measured out the drug carefully, and without hesitation his companions took what he gave them. as they all three started growing--it was loto's first experience, and he gave an exclamation of fright at the sensation and threw his arms around aura again--the very young man made them sit upon the floor near the center of the room. he sat himself beside them, staring up at the ceiling that was steadily folding up and coming down towards them. for some time he stared, fascinated by its ceaseless movement. then suddenly he realized with a start that it was almost down upon them. he put up his hand and touched it, and a thrill of fear ran over him. he looked around. beside him sat aura and loto, huddled close together. the walls of the room had nearly closed in upon them now; its few pieces of furniture had been pushed aside, unnoticed, by the growth of their enormous bodies. it was as though they were crouching in a triangular box, almost entirely filling it. the very young man laid his hand on aura's arm, and she met his anxious glance with her fearless, trusting smile. "we'll have to break through the roof now," whispered the very young man, and the girl answered calmly: "what you say to do, we will do." their heads were bent down now by the ever-lowering ceiling; the very young man pressed his shoulder against it and heaved upwards. he could feel the floor under him quiver and the roof give beneath his thrust, but he did not break through. in sudden horror he wondered if he could. if he did not, soon, they would be crushed to death by their own growth within the room. the very young man knew there was still time to take the other drug. he shoved again, but with the same result. their bodies were bent double now. the ceiling was pressing close upon them; the walls of the room were at their elbow. the very young man crooked his arm through the little square orifice window that he found at his side, and, with a signal to his companions, all three in unison heaved upwards with all their strength. there came one agonizing instant of resistance; then with a wrenching of wood, the clatter of falling stones and a sudden crash, they burst through and straightened upright into the open air above. the very young man sat still for a moment, breathing hard. overhead stretched the canopy of stars; around lay the city, shrunken now and still steadily diminishing. then he got unsteadily upon his feet, pulling his companions up with him and shaking the bits of stone and broken wood from him as he did so. in a moment more the palace roof was down to their knees, and they stepped out of the room. they heard a cry from below and saw the two guards, standing amidst the debris, looking up at them through the torn roof in fright and astonishment. there came other shouts from within the palace now, and the sound of the hurrying of many little feet. for some minutes more they grew larger, as they stood upon the palace roof, clinging to one another and listening to the spreading cries of excitement within the building and in the city streets below them. "come on," said the very young man finally, and he jumped off the roof into the street. a group of little figures scattered as he landed, and he narrowly escaped treading upon them. so large had they grown that it was hardly more than a step down from the roof; aura and loto were by the very young man's side in a moment, and immediately they started off, picking their way single file out of the city. for a short time longer they continued growing; when they had stopped the city houses stood hardly above their ankles. it was difficult walking, for the street was narrow and the frightened people in it were often unable to avoid their tread, but fortunately the palace stood near the edge of the city, and soon they were past its last houses and out into the open country. "well, we did it," said the very young man, exulting. then he patted loto affectionately upon the shoulder, adding. "well, little brother, we got you back, didn't we?" aura stopped suddenly. "look there--at arite," she said, pointing up at the horizon ahead of them. far in the distance, at the edge of the lake, and beside a dim smudge he knew to be the houses of arite, the very young man saw the giant figure of a man, huge as himself, towering up against the background of sky. chapter xxxiv the decision "giants!" exclaimed the doctor, staring across the country towards orlog. there was dismay in his voice. the big business man, standing beside him, clutched at his robe. "how many do you make out; they look like three to me." the doctor strained his eyes into the dim, luminous distance. "three, i think--one taller than the others; it must be jack." his voice was a little husky, and held none of the confidence his words were intended to convey. lylda was upon her feet now, standing beside the chemist. she stared towards orlog searchingly, then turned to him and said quietly, "it must be jack and aura, with loto." she stopped with quivering lips; then with an obvious effort went on confidently. "it cannot be that the god you believe in would let anything happen to them." "they're coming this way--fast," said the big business man. "we'll know in a few moments." the figures, plainly visible now against the starry background, were out in the open country, half a mile perhaps from the lake, and were evidently rapidly approaching arite. "if it should be targo's men," the big business man added, "we must take more of the drug. it is death then for them or for us." in silence the six of them stood ankle deep in the water waiting. the multitude of little people on the beach and in the nearby city streets were dispersing now. a steady stream was flowing up the steps from the beach, and back into the city. five minutes more and only a fringe of those in whom frenzy still raged remained at the water's edge; a few of these, more daring, or more unreasoning than the others, plunged into the lake and swam about the giants' ankles unnoticed. suddenly lylda gave a sigh of relief. "aura it is," she cried. "can you not see, there at the left? her short robe--you see--and her hair, flowing down so long; no man is that." "you're right," said the big business man. "the smallest one on this side is loto; i can see him. and jack is leading. it's all right; they're safe. thank god for that; they're safe, thank god!" the fervent relief in his voice showed what a strain he had been under. it was jack; a moment more left no doubt of that. the big business man turned to the chemist and lylda, where they stood close together, and laying a hand upon the shoulder of each said with deep feeling: "we have all come through it safely, my friends. and now the way lies clear before us. we must go back, out of this world, to which we have brought only trouble. it is the only way; you must see that." lylda avoided his eyes. "all through it safely," she murmured after him. "all safe except--except my father." her arm around the chemist tightened. "all safe--except those." she turned her big, sorrowful eyes towards the beach, where a thousand little mangled figures lay dead and dying. "all safe--except those." it was only a short time before the adventurers from orlog arrived, and loto was in his mother's arms. the very young man, with mixed feelings of pride at his exploit and relief at being freed from so grave a responsibility, happily displayed aura to his friends. "gosh, i'm glad we're all together again; it had me scared, that's a fact." his eye fell upon the beach. "great scott, you've been having a fight, too? look at that." the big business man and the doctor outlined briefly what had happened, and the very young man answered in turn with an account of his adventures. aura joined her sister and loto. the chemist after a moment stood apart from the others thinking deeply. he had said little during all the events of the afternoon and evening. now he reached the inevitable decision that events had forced upon him. his face was very serious as he called his companions around him. "we must decide at once," he began, looking from one to the other, "what we are to do. our situation here has become intolerable--desperate. i agree with you," his glance rested on the big business man an instant; "by staying here we can only do harm to these misguided people." "of course," the big business man interjected under his breath. "if the drugs should ever get out of our possession down here, immeasurable harm would result to this world, as well as causing our own deaths. if we leave now, we save ourselves; although we leave the oroids ruled by targo. but without the power of the drugs, he can do only temporary harm. eventually he will be overthrown. it is the best way, i think. and i am ready to leave." "it's the only way," the big business man agreed. "don't you think so?" the doctor and the very young man both assented. "the sooner the better," the very young man added. he glanced at aura, and the thought that flashed into his mind made his heart jump violently. the chemist turned to lylda. "to leave your people," he said gently, "i know how hard it is. but your way now lies with me--with us." he pulled loto up against him as he spoke. lylda bowed her head. "you speak true, my husband, my way does lie with you. i cannot help the feeling that we should stay. but with you my way does lie; whither you direct, we shall go--for ever." the chemist kissed her tenderly. "my sister also?" he smiled gently at aura. "my way lies with you, too," the girl answered simply. "for no man here has held my heart." the very young man stepped forward. "do we take them with us?" he indicated oteo and eena, who stood silently watching. "ask them, lylda," said the chemist. calling them to her, lylda spoke to the youth and the girl in her native tongue. they listened quietly; oteo with an almost expressionless stolidity of face, but with his soft, dog-like eyes fixed upon his mistress; eena with heaving breast and trembling limbs. when lylda paused they both fell upon their knees before her. she put her hands upon their heads and smiling wistfully, said in english: "so it shall be; with me you shall go, because that is what you wish." the very young man looked around at them all with satisfaction. "then it's all settled," he said, and again his glance fell on aura. he wondered why his heart was pounding so, and why he was so thrilled with happiness; and he was glad he was able to speak in so matter-of-fact a tone. "i don't know how about you," he added, "but, great scott, i'm hungry." "since we have decided to go," the chemist said, "we had better start as soon as possible. are there things in the house, lylda, that you care to take?" lylda shook her head. "nothing can i take but memories of this world, and those would i rather leave." she smiled sadly. "there are some things i would wish to do--my father----" "it might be dangerous to wait," the big business man put in hurriedly. "the sooner we start, the better. another encounter would only mean more death." he looked significantly at the beach. "we've got to eat," said the very young man. "if we handle the drugs right," the chemist said, "we can make the trip out in a very short time. when we get above the forest and well on our way we can rest safely. let us start at once." "we've got to eat," the very young man insisted. "and we've got to have food with us." the chemist smiled. "what you say is quite true, jack, we have got to have food and water; those are the only things necessary to our trip." "we can make ourselves small now and have supper," suggested the very young man. "then we can fill up the bottles for our belts and take enough food for the trip." "no, we won't," interposed the big business man positively. "we won't get small again. something might happen. once we get through the tunnels----" he stopped abruptly. "great scott! we never thought of that," ejaculated the very young man, as the same thought occurred to him. "we'll have to get small to get through the tunnels. suppose there's a mob there that won't let us in?" "is there any other way up to the forest?" the doctor asked. the chemist shook his head. "there are a dozen different tunnels, all near here, and several at orlog, that all lead to the upper surface. but i think that is the only way." "they might try to stop us," the big business man suggested. "we certainly had better get through them as quickly as we possibly can." it was aura who diffidently suggested the plan they finally adopted. they all reduced their size first to about the height of the chemist's house. then the very young man prepared to make himself sufficiently small to get the food and water-bottles, and bring them up to the larger size. "keep your eye on me," he warned. "somebody might jump on me." they stood around the house, while the very young man, in the garden, took the drug and dwindled in stature to oroid size. there were none of the oroids in sight, except some on the beach and others up the street silently watching. as he grew smaller the very young man sat down wearily in the wreck of what once had been lylda's beautiful garden. he felt very tired and hungry, and his head was ringing. when he was no longer changing size he stood up in the garden path. the house, nearly its proper dimensions once more, was close at hand, silent and deserted. aura stood in the garden beside it, her shoulders pushing aside the great branches of an overhanging tree, her arm resting upon the roof-top. the very young man waved up at her and shouted: "be out in a minute," and then plunged into the house. chapter xxxv good-by to arite once inside he went swiftly to the room where they had left their water-bottles and other paraphernalia. he found them without difficulty, and retraced his steps to the door he had entered. depositing his load near it, he went back towards the room which lylda had described to him, and in which the food was stored. walking along this silent hallway, listening to the echoes of his own footsteps on its stone floor, the very young man found himself oppressed by a feeling of impending danger. he looked back over his shoulder--once he stood quite still and listened. but he heard nothing; the house was quite silent, and smiling at his own fear he went on again. selecting the food they needed for the trip took him but a moment. he left the storeroom, his arms loaded, and started back toward the garden door. several doorways opened into the hall below, and all at once the very young man found himself afraid as he passed them. he was within sight of the garden door, not more than twenty feet away, when he hesitated. just ahead, at his right, an archway opened into a room beside the hall. the very young man paused only an instant; then, ashamed of his fear, started slowly forward. he felt an impulse to run, but he did not. and then, from out of the silence, there came a low, growling cry that made his heart stand still, and the huge gray figure of a man leaped upon him and bore him to the ground. as he went down, with the packages of food flying in all directions, the very young man gripped the naked body of his antagonist tightly. he twisted round as he fell and lay with his foe partly on top of him. he knew instinctively that his situation was desperate. the man's huge torso, with its powerful muscles that his arms encircled, told him that in a contest of strength such as this, inevitably he would find himself overcome. the man raised his fist to strike, and the very young man caught him by the wrist. over his foe's shoulder now he could see the open doorway leading into the garden, not more than six or eight feet away. beyond it lay safety; that he knew. he gave a mighty lunge and succeeded in rolling over toward the doorway. but he could not stay above his opponent, for the man's greater strength lifted him up and over, and again pinned him to the floor. he was nearer the door now, and just beyond it he caught a glimpse of the white flesh of aura's ankle as she stood beside the house. the man put a hand on the very young man's throat. the very young man caught it by the wrist, but he could feel the growing pressure of its fingers cutting off his breath. he tried to pull the hand back, but could not; he tried to twist his body free, but the weight of his foe held him tightly against the floor. a great roaring filled his ears; the hallway began fading from his sight. with a last despairing breath, he gave a choking cry: "aura! aura!" the man's fingers at his throat loosened a little; he drew another breath, and his head cleared. his eyes were fixed on the strip of garden he could see beyond the doorway. suddenly aura's enormous body came into view, as she stooped and then lay prone upon the ground. her face was close to the door; she was looking in. the very young man gave another cry, half stifled. and then into the hallway he saw come swiftly a huge hand, whose fingers gripped him and his antagonist and jerked them hurriedly down the hall and out into the garden. as they lay struggling on the ground outside, the very young man felt himself held less closely. he wrenched himself free and sprang to his feet, standing close beside aura's face. the man was up almost as quickly, preparing again to spring upon his victim. something moved behind the very young man, and he looked up into the air hurriedly. the big business man stood behind him; the very young man met his anxious glance. "i'm all right," he shouted. his antagonist leaped forward and at the same instant a huge, flat object, that was the big business man's foot, swept through the air and mashed the man down into the dirt of the garden. the very young man turned suddenly sick as he heard the agonized shriek and the crunching of the breaking bones. the big business man lifted his foot, and the mangled figure lay still. the very young man sat down suddenly in the garden path and covered his face with his hands. when he raised his head his friends were all standing round him, crowding the garden. the body of the man who had attacked him had disappeared. the very young man looked up into aura's face--she was on her feet now with the others and tried to smile. "i'm all right," he repeated. "i'll go get the food and things." in a few minutes more he had made himself as large as his companions, and had brought with him most of the food. there still remained in the smaller size the water-bottles, some of the food, the belts with which to carry it, and a few other articles they needed for the trip. "i'll get them," said the big business man; "you sit down and rest." the very young man was glad to do as he was told, and sat beside aura in the garden, while the big business man brought up to their size the remainder of the supplies. when they had divided the food, and all were equipped for the journey, they started at once for the tunnels. lylda's eyes again filled with tears as she left so summarily, and probably for the last time, this home in which she had been so happy. as they passed the last houses of the city, heading towards the tunnel entrances that the chemist had selected, the big business man and the chemist walked in front, the others following close behind them. a crowd of oroids watched them leave, and many others were to be seen ahead; but these scattered as the giants approached. occasionally a few stood their ground, and these the big business man mercilessly trampled under foot. "it's the only way; i'm sorry," he said, half apologetically. "we cannot take any chances now; we must get out." "it's shorter through these tunnels i'm taking," the chemist said after a moment. "my idea," said the big business man, "is that we should go through the tunnels that are the largest. they're not all the same size, are they?" "no," the chemist answered; "some are a little larger." "you see," the big business man continued, "i figure we are going to have a fight. they're following us. look at that crowd over there. they'll never let us out if they can help it. when we get into the tunnels, naturally we'll have to be small enough to walk through them. the larger we are the better; so let's take the very biggest." "these are," the chemist answered. "we can make it at about so high." he held his hand about the level of his waist. "that won't be so bad," the big business man commented. meanwhile the very young man, walking with aura behind the leaders, was talking to her earnestly. he was conscious of a curious sense of companionship with this quiet girl--a companionship unlike anything he had ever felt for a girl before. and now that he was taking her with him, back to his own world---- "climb out on to the surface of the ring," he was saying, "and then, in a few minutes more, we'll be there. aura, you cannot realize how wonderful it will be." the girl smiled her quiet smile; her face was sad with the memory of what she was leaving, but full of youthful, eager anticipation of that which lay ahead. "so much has happened, and so quickly, i cannot realize it yet, i know," she answered. "but that it will be very wonderful, up there above, i do believe. and i am glad that we are going, only----" the very young man took her hand, holding it a moment. "don't, aura. you mustn't think of that." he spoke gently, with a tender note in his voice. "don't think of the past, aura," he went on earnestly. "think only of the future--the great cities, the opera, the poetry i am going to teach you." the girl laid her hand on his arm. "you are so kind, my friend jack. you will have much to teach me, will you not? is it sure you will want to? i shall be like a little child up there in your great world." an answer sprang to the very young man's lips--words the thinking of which made his heart leap into his throat. but before he could voice them loto ran up to him from behind, crying. "i want to walk by you, jack; _mamita_ talks of things i know not." the very young man put his arm across the child's shoulders. "well, little boy," he said laughing, "how do you like this adventure?" "never have i been in the great forests," loto answered, turning his big, serious eyes up to his friend's face. "i shall not be afraid--with my father, and _mamita_, and with you." "the great forests won't seem very big, loto, after a little while," the very young man said. "and of course you won't be afraid of anything. you're going to see many things, loto--very many strange and wonderful things for such a little boy." they reached the entrance to the tunnel in a few moments more, and stopped before it. as they approached, a number of little figures darted into its luminous blackness and disappeared. there were none others in sight now, except far away towards arite, where perhaps a thousand stood watching intently. the tunnel entrance, against the side of a hill, stood nearly breast high. "i'm wrong," said the chemist, as the others came up. "it's not so high all the way through. we shall have to make ourselves much smaller than this." "this is a good time to eat," suggested the very young man. the others agreed, and without making themselves any smaller--the big business man objected to that procedure--they sat down before the mouth of the tunnel and ate a somewhat frugal meal. "have you any plans for the trip up?" asked the doctor of the chemist while they were eating. "i have," interjected the big business man, and the chemist answered: "yes, i am sure i can make it far easier than it was for me before. i'll tell you as we go up; the first thing is to get through the tunnels." "i don't anticipate much difficulty in that," the doctor said. "do you?" the chemist shook his head. "no, i don't." "but we mustn't take any chances," put in the big business man quickly. "how small do you suppose we should make ourselves?" the chemist looked at the tunnel opening. "about half that," he replied. "not at the start," said the big business man. "let's go in as large as possible; we can get smaller when we have to." it took them but a few minutes to finish the meal. they were all tired from the exciting events of the day, but the big business man would not hear of their resting a moment more than was absolutely necessary. "it won't be much of a trip up to the forests," he argued. "once we get well on our way and into one of the larger sizes, we can sleep safely. but not now; it's too dangerous." they were soon ready to start, and in a moment more all had made themselves small enough to walk into the tunnel opening. they were, at this time, perhaps six times the normal height of an adult oroid. the city of arite, apparently much farther away now, was still visible up against the distant horizon. as they were about to start, lylda, with aura close behind her, turned to face it. "good-by to our own world now we must say, my sister," she said sadly. "the land that bore us--so beautiful a world, and once so kindly. we have been very happy here. and i cannot think it is right for me to leave." "your way lies with your husband," aura said gently. "you yourself have said it, and it is true." lylda raised her arms up towards the far-away city with a gesture almost of benediction. "good future to you, land that i love." her voice trembled. "good future to you, for ever and ever." the very young man, standing behind them with loto, was calling: "they're started; come on." with one last sorrowful glance lylda turned slowly, and, walking with her arm about her sister, followed the others into the depths of the tunnel. chapter xxxvi the fight in the tunnels for some time this strange party of refugees from an outraged world walked in silence. because of their size, the tunnel appeared to them now not more than eight or nine feet in height, and in most places of nearly similar width. for perhaps ten minutes no one spoke except an occasional monosyllable. the chemist and big business man, walking abreast, were leading; aura and lylda with the very young man, and loto close in front of them, brought up the rear. the tunnel they were traversing appeared quite deserted; only once, at the intersection of another smaller passageway, a few little figures--not more than a foot high--scurried past and hastily disappeared. once the party stopped for half an hour to rest. "i don't think we'll have any trouble getting through," said the chemist. "the tunnels are usually deserted at the time of sleep." the big business man appeared not so sanguine, but said nothing. finally they came to one of the large amphitheaters into which several of the tunnels opened. in size, it appeared to them now a hundred feet in length and with a roof some twelve feet high. the chemist stopped to let the others come up. "i think our best route is there," he pointed. "it is not so high a tunnel; we shall have to get smaller. beyond it they are larger again. it is not far--half an hour, perhaps, walking as we----" a cry from aura interrupted him. "my brother, see, they come," she exclaimed. before them, out of several of the smaller passageways, a crowd of little figures was pouring. there were no shouts; there was seemingly no confusion; just a steady, flowing stream of human forms, emptying from the tunnels into the amphitheater and spreading out over its open surface. the fugitives stared a moment in horror. "good god! they've got us," the doctor muttered, breaking the tenseness of the silence. the little people kept their distance at first, and then as the open space filled up, slowly they began coming closer, in little waves of movement, irresistible as an incoming tide. aura turned towards the passageway through which they had entered. "we can go back," she said. and then. "no--see, they come there, too." a crowd of the little gray figures blocked that entrance also--a crowd that hesitated an instant and then came forward, spreading out fan-shape as it came. the big business man doubled up his fists. "it's fight," he said grimly. "by god! we'll----" but lylda, with a low cry, flung herself before him. "no, no," she said passionately. "not that; it cannot be that now, just at the last----" aura laid a hand upon her sister's shoulder. "wait, my sister," she said gently. "there is no matter of justice here--for you, a woman--to decide. this is for men to deal with--a matter for men--our men. and what they say to do--that must be done." she turned to the chemist and the very young man, who were standing side by side. "a woman--cannot kill," she said slowly. "unless--her man--says it so. or if to save him----" her eyes flashed fire; she held her slim little body erect and rigid--an amazon ready to fight to the death for those she loved. the chemist hesitated a moment. before he could answer, a single shrill cry sounded from somewhere out in the silent, menacing throng. as though at a signal, a thousand little voices took it up, and with a great rush the crowd swept forward. in the first moment of surprise and indecision the group of fugitives stood motionless. as the wave of little, struggling human forms closed in around them, the very young man came to himself with a start. he looked down. they were black around him now, swaying back and forth about his legs. most of them were men, armed with the short, broad-bladed swords, or with smaller knives. some brandished other improvised weapons; still others held rocks in their hands. a little pair of arms clutched the very young man about his leg; he gave a violent kick, scattering a number of the struggling figures and clearing a space into which he leaped. "back--aura, lylda," he shouted. "take loto and eena. get back behind us." the big business man, kicking violently, and sometimes stooping down to sweep the ground with great swings of his arm, had cleared a space before them. taking loto, who looked on with frightened eyes, the three women stepped back against the side wall of the amphitheater. the very young man swiftly discarded his robe, standing in the knitted under-suit in which he had swam the lake; the other men followed his example. for ten minutes or more in ceaseless waves, the little creatures threw themselves forward, and were beaten back. the confined space echoed with their shouts, and with the cries of the wounded. the five men fought silently. once the doctor stumbled and fell. before his friends could get to him, his body was covered with his foes. when he got back upon his feet, knocking them off, he was bleeding profusely from an ugly-looking wound in his shoulder. "good god!" he panted as the chemist and the big business man leaped over to him. "they'll get us--if we go down." "we can get larger," said the big business man, pointing upwards to the roof overhead. "larger--and then----" he swayed a trifle, breathing hard. his legs were covered with blood from a dozen wounds. oteo, fighting back and forth before them, was holding the crowd in check; a heap of dead lay in a semicircle in front of him. "i'm going across," shouted the very young man suddenly, and began striding forward into the struggling mass. the crowd, thus diverted, eased its attack for a moment. slowly the very young man waded into it. he was perhaps fifty feet out from the side wall when a stone struck him upon the temple. he went down, out of sight in the seething mass. "come on," shouted the big business man. but before he could move, aura dashed past him, fighting her way out to where the very young man lay. in a moment she was beside him. her fragile body seemed hopelessly inadequate for such a struggle, but the spirit within her made her fight like a wild-cat. catching one of the little figures by the legs she flung him about like a club, knocking a score of the others back and clearing a space about the very young man. then abruptly she dropped her victim and knelt down, plucking away the last of the attacking figures who was hacking at the very young man's arm with his sword. the chemist and big business man were beside her now, and together they carried the very young man back. he had recovered consciousness, and smiled up at them feebly. they laid him on the ground against the wall, and aura sat beside him. "gosh, i'm all right," he said, waving them away. "be with you in a minute; give 'em hell!" the doctor knelt beside the very young man for a moment, and, finding he was not seriously hurt, left him and rejoined the chemist and big business man, who, with oteo, had forced the struggling mass of little figures some distance away. "i'm going to get larger," shouted the big business man a moment later. "wipe them all out, damn it; i can do it. we can't keep on this way." the doctor was by his side. "you can't do it--isn't room," he shouted in answer, pausing as he waved one of his assailants in the air above his head. "you might take too much." the big business man was reaching with one hand under his robe. with his feet he kicked violently to keep the space about him clear. a tiny stone flew by his head; another struck him on the chest, and all at once he realized that he was bruised all over from where other stones had been hitting him. he looked across to the opposite wall of the amphitheater. through the tunnel entrance there he saw that the stream of little people was flowing the other way now. they were trying to get out, instead of pouring in. the big business man waved his arms. "they're running away--look," he shouted. "they're running--over there--come on." he dashed forward, and, followed by his companions, redoubled his efforts. the crowd wavered; the shouting grew less; those further away began running back. then suddenly a shrill cry arose--just a single little voice it was at first. after a moment others took it up, and still others, until it sounded from every side--three oroid words repeated over and over. the chemist abruptly stopped fighting. "it's done," he shouted. "thank god it's over." the cry continued. the little figures had ceased attacking now and were struggling in a frenzy to get through the tunnels. "no more," shouted the chemist. "they're going. see them going? stop." his companions stood by his side, panting and weak from loss of blood. the chemist tried to smile. his face was livid; he swayed unsteadily on his feet. "no more," he repeated. "it's over. thank god, it's over!" meanwhile the very young man, lying on the floor with aura sitting beside him, revived a little. he tried to sit up after a few moments, but the girl pulled him down. "but i got to go--give 'em hell," he protested weakly. his head was still confused; he only knew he should be back, fighting beside his friends. "not yet," aura said gently. "there is no need--yet. when there is, you may trust me, jack; i shall say it." the very young man closed his eyes. the blurred, iridescent outlines of the rocks confused him; his head was ringing. the girl put an arm under his neck. he found one of her hands, and held it tightly. for a moment he lay silent. then his head seemed to clear a little; he opened his eyes. "what are they doing now, aura?" he asked. "it is no different," the girl answered softly. "so terrible a thing--so terrible----" she finished almost to herself. "i'll wait--just a minute more," he murmured and closed his eyes again. he held the girl's hand tighter. he seemed to be floating away, and her hand steadied him. the sounds of the fighting sounded very distant now--all blurred and confused and dreamlike. only the girl's nearness seemed real--the touch of her little body against his as she sat beside him. "aura," he whispered. "aura." she put her face down to his. "yes, jack," she answered gently. "it's very bad--there--don't you think?" she did not answer. "i was just thinking," he went on; he spoke slowly, almost in a whisper. "maybe--you know--we won't come through this." he paused; his thoughts somehow seemed too big to put into words. but he knew he was very happy. "i was just thinking, aura, that if we shouldn't come through i just wanted you to know----" again he stopped. from far away he heard the shrill, rhythmic cry of many voices shouting in unison. he listened, and then it all came back. the battle--his friends there fighting--they needed him. he let go of the girl's hand and sat up, brushing back his moist hair. "listen, aura. hear them shouting; i mustn't stay here." he tried, weakly, to get upon his feet, but the girl's arm about his waist held him down. "wait," she said. surprised by the tenseness of her tone, he relaxed. the cry grew louder, rolling up from a thousand voices and echoing back and forth across the amphitheater. the very young man wondered vaguely what it could mean. he looked into aura's face. her lips were smiling now. "what is it, aura?" he whispered. the girl impulsively put her arms about him and held him close. "but we are coming through, my friend jack. we are coming through." the very young man looked wonderingly into her eyes. "don't you hear? that cry--the cry of fear and despair. it means--life to us; and no more death--to them." the chemist's voice came out of the distance shouting: "they're running away. it's over; thank god it's over!" then the very young man knew, and life opened up before him again. "life," he whispered to himself. "life and love and happiness." chapter xxxvii a combat of titans in a few minutes the amphitheater was entirely clear, save for the dead and maimed little figures lying scattered about; but it was nearly an hour more before the fugitives were ready to resume their journey. the attack had come so suddenly, and had demanded such immediate and continuous action that none of the men, with the exception of the very young man, had had time to realize how desperate was the situation in which they had fallen. with the almost equally abrupt cessation of the struggle there came the inevitable reaction; the men bleeding from a score of wounds, weak from loss of blood, and sick from the memory of the things they had been compelled to do, threw themselves upon the ground utterly exhausted. "we must get out of here," said the doctor, after they had been lying quiet for a time, with the strident shrieks of hundreds of the dying little creatures sounding in their ears. "that was pretty near the end." "it isn't far," the chemist answered, "when we get started." "we must get water," the doctor went on. "these cuts----" they had used nearly all their drinking-water washing out their wounds, which aura and lylda had bound up with strips of cloth torn from their garments. the chemist got upon his feet. "there's no water nearer than the forest river," he said. "that tunnel over there comes out very near it." "what makes you think we won't have another scrap getting out?" the very young man wanted to know. he had entirely recovered from the effects of the stone that had struck him on the temple, and was in better condition than any of the other men. "i'm sure," the chemist said confidently, "they were through; they will not attack us again; for some time at least. the tunnels will be deserted." the big business man stood up also. "we'd better get going while we have the chance," he said. "this getting smaller--i don't like it." they started soon after, and, true to the chemist's prediction, met no further obstacle to their safe passage through the tunnels. when they had reached the forest above, none of the little people were in sight. the big business man heaved a long sigh of relief. "thank goodness we're here at last," he said. "i didn't realize how good these woods would look." in a few minutes more they were at the edge of the river, bathing their wounds in its cooling water, and replenishing their drinking-bottles. "how do we get across?" the very young man asked. "we won't have to cross it," the chemist answered with a smile. "the tunnel took us under." "let's eat here," the very young man suggested, "and take a sleep; we're about all in." "we ought to get larger first," protested the big business man. they were at this time about four times oroid size; the forest trees, so huge when last they had seen them, now seemed only rather large saplings. "some one of us must stay awake," the doctor said. "but there do not seem to be any oroids up here." "what do they come up here for, anyway?" asked the very young man. "there's some hunting," the chemist answered. "but principally it's the mines beyond, in the deserts." they agreed finally to stop beside the river and eat another meal, and then, with one of them on guard, to sleep for a time before continuing their journey. the meal, at the doctor's insistence, was frugal to the extreme, and was soon over. they selected oteo to stand guard first. the youth, when he understood what was intended, pleaded so with his master that the chemist agreed. utterly worn out, the travelers lay down on a mossy bank at the river's edge, and in a few moments were all fast asleep. oteo sat nearby with his back against a tree-trunk. occasionally he got up and walked to and fro to fight off the drowsiness that came over him. * * * * * how long the very young man slept he never knew. he slept dreamlessly for a considerable time. when he struggled back to consciousness it was with a curious feeling of detachment, as though his mind no longer was connected with his body. he thought first of aura, with a calm peaceful sense of happiness. for a long time he lay, drifting along with his thoughts and wondering whether he were asleep or awake. then all at once he knew he was not asleep. his eyes were open; before him stood the forest trees at the river's edge. and at the foot of one of the trees he could see the figure of oteo, sitting hunched up with his head upon his hands, fast asleep. remembrance came to the very young man, and he sat up with a start. beside him his friends lay motionless. he looked around, still a little confused. and then his heart leaped into his throat, for at the edge of the woods he saw a small, lean, gray figure--the little figure of a man who stood against a tree-trunk. the man's face was turned towards him; he met the glistening eyes looking down and saw the lips parted in a leering smile. a thrill of fear ran over the very young man as he recognized the face of targo. and then his heart seemed to stop beating. for as he stared, fascinated, into the man's mocking eyes, he saw that slowly, steadily he was growing larger. mechanically the very young man's hand went to his armpit, his fingers fumbling at the pouch strapped underneath. the vial of chemicals was not there! for an instant more the very young man continued staring. then, with an effort, he turned his eyes away from the gaze that seemed to hypnotize him. beside him the chemist lay sleeping. he looked back at targo, and saw him larger--almost as large now as he was himself. like a cloak discarded, the very young man's bewilderment dropped from him. he recognized the danger, realized that in another moment this enemy would be irresistibly powerful--invincible. his mind was clear now, his nerves steady, his muscles tense. he knew the only thing he could do; he calculated the chances in a flash of thought. still staring at the triumphant face of targo, the very young man jumped to his feet and swiftly bent over the sleeping form of the chemist. reaching through the neck of his robe he took out the vial of chemicals, and before his friend was fairly awake had swallowed one of the pills. as the very young man sprang into action targo turned and ran swiftly away, perhaps a hundred feet; then again he stopped and stood watching his intended victim with his sardonic smile. the very young man met the chemist's startled eyes. "targo!" said the very young man swiftly. "he's here; he stole the drug just now, while i was sleeping." the chemist opened his mouth to reply, but the very young man bounded away. he could feel the drug beginning to work; the ground under his feet swayed unsteadily. swiftly he ran straight towards the figure of targo, where he stood leaning against a tree. his enemy did not move to run away, but stood quietly awaiting him. the very young man saw he was now nearly the same size that targo was; if anything, the larger. a fallen tree separated them; the very young man cleared it with a bound. still targo stood motionless, awaiting his onslaught. then abruptly he stooped to the ground, and a rock whistled through the air, narrowly missing the very young man's head. before targo could recover from the throw the very young man was upon him, and they went down together. back and forth over the soft ground they rolled, first one on top, then the other. the very young man's hand found a stone on the ground beside them. his fingers clutched it; he raised it above him. but a blow upon his forearm knocked it away before he could strike; and a sudden twist of his antagonist's body rolled him over and pinned him upon his back. the very young man thought of his encounter with targo before, and again with sinking heart he realized he was the weaker of the two. he jerked one of his wrists free and, striking upwards with all his force, landed full on his enemy's jaw. the man's head snapped back, but he laughed--a grim, sardonic laugh that ended in a half growl, like a wild beast enraged. the very young man's blood ran cold. a sudden frenzy seized him; he put all his strength into one desperate lunge and, wrenching himself free, sprang to his feet. targo was up almost as quickly as he, and for an instant the two stood eyeing each other, breathing hard. at the very young man's feet a little stream was flowing past. vaguely he found himself thinking how peaceful it looked; how cool and soothing the water would be to his bruised and aching body. beside the stream his eye caught a number of tiny human figures, standing close together, looking up at him--little forms that a single sweep of his foot would have scattered and killed. a shiver of fear ran across him as in a flash he realized this other danger. with a cry, he leaped sidewise, away from the water. beside him stood a little tree whose bushy top hardly reached his waist. he clutched its trunk with both hands and jerking it from the ground swung it at his enemy's head, meeting him just as he sprang forward. the tree struck targo a glancing blow upon the shoulder. with another laugh he grasped its roots and twisted it from the very young man's hand. a second more and they came together again, and the very young man felt his antagonist's powerful arms around his body, bending him backwards. * * * * * the big business man stood beside the others at the river's edge, watching the gigantic struggle, the outcome of which meant life or death to them all. the grappling figures were ten times his own height before he fairly realized the situation. at first he thought he should take some of the drug also, and grow larger with them. then he knew that he could not overtake their growth in time to aid his friend. the chemist and the doctor must evidently have reached the same conclusion, for they, too, did nothing, only stood motionless, speechless, staring up at the battling giants. loto, with his head buried upon his mother's shoulder, and her arms holding him close, whimpered a little in terror. only aura, of all the party, did not get upon her feet. she lay full length upon the ground, a hand under her chin, staring steadily upwards. her face was expressionless, her eyes unblinking. but her lips moved a little, as though she were breathing a silent prayer, and the fingers of her hand against her face dug their nails into the flesh of her cheek. taller far than the tree-tops, the two giants stood facing each other. then the very young man seized one of the trees, and with a mighty pull tore it up by the roots and swung it through the air. aura drew a quick breath as in another instant they grappled and came crashing to the ground, falling head and shoulders in the river with a splash that drenched her with its spray. the very young man was underneath, and she seemed to meet the glance of his great eyes when he fell. the trees growing on the river-bank snapped like rushes beneath the huge bodies of the giants, as, still growing larger, they struggled back and forth. the river, stirred into turmoil by the sweep of their great arms, rolled its waves up over the mossy banks, driving the watchers back into the edge of the woods, and even there covering them with its spray. a moment more and the giants were on their feet again, standing ankle deep, far out in the river. up against the unbroken blackness of the starless sky their huge forms towered. for a second they stood motionless; then they came together again and aura could see the very young man sink on his knees, his hand trailing in the water. then in an instant more he struggled up to his feet; and as his hand left the water aura saw that it clutched an enormous dripping rock. she held her breath, watching the tremendous figures as they swayed, locked in each other's arms. a single step sidewise and they were back nearly at the river's bank; the water seethed white under their tread. the very young man's right arm hung limp behind him; the boulder in his hand dangled a hundred feet or more in the air above the water. slowly the greater strength of his antagonist bent him backwards. aura's heart stood still as she saw targo's fingers at the very young man's throat. then, in a great arc, the very young man swept the hand holding the rock over his head, and brought it down full upon his enemy's skull. the boulder fell into the river with a thundering splash. for a brief instant the giant figures hung swaying; then the titanic hulk of targo's body came crashing down. it fell full across the river, quivered convulsively and lay still. and the river, backing up before it a moment, turned aside in its course, and flung the muddy torrent of its water roaring down through the forest. chapter xxxviii lost in size the very young man stood ankle deep in the turgid little rivulet, a tightness clutching at his chest, and with his head whirling. at his feet his antagonist lay motionless. he stepped out of the water, putting his foot into a tiny grove of trees that bent and crackled like twigs under his tread. he wondered if he would faint; he knew he must not. away to the left he saw a line of tiny hills; beyond that a luminous obscurity into which his sight could not penetrate; behind him there was only darkness. he seemed to be standing in the midst of a great barren waste, with just a little toy river and forest at his feet--a child's plaything, set down in a man's great desert. the very young man suddenly thought of his friends. he stepped into the middle of the river and out again on the other side. then he bent down with his face close to the ground, just above the tops of the tiny little trees. he made the human figures out finally. hardly larger than ants they seemed, and he shuddered as he saw them. the end of his thumb could have smashed them all, they were so small. one of the figures seemed to be waving something, and the very young man thought he heard the squeak of its voice. he straightened upright, standing rigid, afraid to move his feet. he wondered what he should do, and in sudden fear felt for the vial of the diminishing drug. it was still in place, in the pouch under his armpit. the very young man breathed a sigh of relief. he decided to take the drug and rejoin his friends. then as a sudden thought struck him he bent down to the ground again, slowly, with infinite caution. the little figures were still there; and now he thought they were not quite as tiny as before. he watched them; slowly but unmistakably they were growing larger. the very young man carefully took a step backwards, and then sat down heavily. the forest trees crackled under him. he pulled up his knees, and rested his head upon them. the little rivulet diverted from its course by the body of targo, swept past through the woods almost at his side. the noise it made mingled with the ringing in his head. his body ached all over; he closed his eyes. * * * * * "he's all right now," the doctor's voice said. "he'll be all right in a moment." the very young man opened his eyes. he was lying upon the ground, with aura sitting beside him, and his friends--all his own size again--standing over him. he met aura's tender, serious eyes, and smiled. "i'm all right," he said. "what a foolish thing to faint." lylda stooped beside him, "you saved us all," she said. "there is nothing we can say--to mean what it should. but you will always know how we feel; how splendid you were." to the praise they gave him the very young man had no answer save a smile of embarrassment. aura said nothing, only met his smile with one of her own, and with a tender glance that made his heart beat faster. "i'm all right," he repeated after a moment of silence. "let's get started." they sat down now beside the very young man, and earnestly discussed the best plan for getting out of the ring. "you said you had calculated the best way," suggested the doctor to the chemist. "first of all," interrupted the big business man. "are we sure none of these oroids is going to follow us? for heaven's sake let's have done with these terrible struggles." the very young man remembered. "he stole one of the vials," he said, pointing to targo's body. "he was probably alone," the chemist reasoned. "if any others had been with him they would have taken some of the drug also. probably targo took one of the pills and then dropped the vial to the ground." "my idea," pursued the big business man, "is for us to get large just as quickly and continuously as possible. probably you're right about targo, but don't let's take any chances. "i've been thinking," he continued, seeing that they agreed with him. "you know this is a curious problem we have facing us. i've been thinking about it a lot. it seemed a frightful long trip down here, but in spite of that, i can't get it out of my mind that we're only a very little distance under the surface of the ring." "it's absolutely all in the viewpoint," the chemist said with a smile. "that's what i meant about having an easier method of getting out. the distance depends absolutely on how you view it." "how far would it be out if we didn't get any larger?" the very young man wanted to know. "based on the size of a normal oroid adult, and using the terrestrial standard of feet and inches as they would seem to us when oroid size, i should say the distance from arite to the surface of the ring would be about one hundred and fifty to a hundred and sixty thousand miles." "holy mackerel!" exclaimed the very young man. "don't let's do much walking while we're small." "you have the idea exactly," smiled the chemist. "taking the other viewpoint," said the doctor. "just where do you figure this oroid universe is located in the ring?" "it is contained within one of the atoms of gold," the chemist answered. "and that golden atom, i estimate, is located probably within one one-hundredth of an inch, possibly even one one-thousandth of an inch away from the circular indentation i made in the bottom of the scratch. in actual distance i suppose arite is possibly one-sixteenth of an inch below the surface of the ring." "certainly makes a difference how you look at it," murmured the very young man in awe. the chemist went on. "it is obvious then, that although when coming down the distance must be covered to some extent by physical movement--by traveling geographically, so to speak--going back, that is not altogether the case. most of the distance may be covered by bodily growth, rather than by a movement of the body from place to place." "we might get lost," objected the very young man. "suppose we got started in the wrong direction?" "coming in, that is a grave danger," answered the chemist, "because then distances are opening up and a single false step means many miles of error later on. but going out, just the reverse is true; distances are shortening. a mile in the wrong direction is corrected in an instant later on. not coming to a realization of that when i made the trip before, led me to undertake many unnecessary hours of most arduous climbing. there is only one condition imperative; the body growing must have free space for its growth, or it will be crushed to death." "have you planned exactly how we are to get out?" asked the big business man. "yes, i have," the chemist answered. "in the size we are now, which you must remember is several thousand times oroid height, it will be only a short distance to a point where as we grow we can move gradually to the centre of the circular pit. that huge inclined plane slides down out of it, you remember. once in the pit, with its walls closing in upon us, we can at the proper moment get out of it about as i did before." "then we'll be in the valley of the scratch," exclaimed the very young man eagerly. "i'll certainly be glad to get back there again." "getting out of the valley we'll use the same methods," the chemist continued. "there we shall have to do some climbing, but not nearly so much as i did." the very young man was thrilled at the prospect of so speedy a return to his own world. "let's get going," he suggested quickly. "it sounds a cinch." they started away in a few minutes more, leaving the body of targo lying where it had fallen across the river. in half an hour of walking they located without difficulty the huge incline down which the chemist had fallen when first he came into the ring. following along the bottom of the incline they reached his landing place--a mass of small rocks and pebbles of a different metallic-looking stone than the ground around marking it plainly. these were the rocks and boulders that had been brought down with him in his fall. "from here," said the chemist, as they came to a halt, "we can go up into the valley by growth alone. it is several hours, but we need move very little from this position." "how about eating?" suggested the very young man. they sat down at the base of the incline and ate another meal--rather a more lavish one this time, for the rest they had taken, and the prospect of a shorter journey ahead of them than they had anticipated made the doctor less strict. then, the meal over, they took the amount of the drug the chemist specified. he measured it carefully--more than ten of the pills. "we have a long wait," the chemist said, when the first sickness from this tremendous dose had left them. the time passed quickly. they spoke seldom, for the extraordinary rapidity with which the aspect of the landscape was changing, and the remarkable sensations they experienced, absorbed all their attention. in about two hours after taking the drug the curving, luminous line that was the upper edge of the incline came into view, faint and blurred, but still distinct against the blackness of the sky. the incline now was noticeably steeper; each moment they saw its top coming down towards them out of the heights above, and its surface smoothing out and becoming more nearly perpendicular. they were all standing up now. the ground beneath them seemed in rapid motion, coming towards them from all directions, and dwindling away beneath their feet. the incline too--now in form a vertical concave wall--kept shoving itself forward, and they had to step backwards continually to avoid its thrust. within another hour a similar concave wall appeared behind them which they could follow with their eyes entirely around the circumference of the great pit in which they now found themselves. the sides of this pit soon became completely perpendicular--smooth and shining. another hour and the action of the drug was beginning to slacken--the walls encircling them, although steadily closing in, no longer seemed to move with such rapidity. the pit as they saw it now was perhaps a thousand feet in diameter and twice as deep. far overhead the blackness of the sky was beginning to be tinged with a faint gray-blue. at the chemist's suggestion they walked over near the center of the circular enclosure. slowly its walls closed in about them. an hour more and its diameter was scarcely fifty feet. the chemist called his companions around him. "there is an obstacle here," he began, "that we can easily overcome; but we must all understand just what we are to do. in perhaps half an hour at the rate we are growing this enclosure will resemble a well twice as deep, approximately, as it is broad. we cannot climb up its sides, therefore we must wait until it is not more than six feet in depth in order to be able to get out. at that time its diameter will be scarcely three feet. there are nine of us here; you can realize there would not be room for us all. "what we must do is very simple. since there is not room for us all at once, we must get large from now on only one at a time." "quite so," said the big business man in a perfectly matter-of-fact tone. "all of us but one will stop growing now; one will go on and get out of the pit. he will immediately stop his growth so that he can wait for the others and help them out. each of us will follow the same method of procedure." the chemist then went on to arrange the exact quantities of the drugs they were each to take at specified times, so that at the end they would all be nearly the same size again. when he had explained all this to oteo and eena in their native language, they were ready to proceed with the plan. "who's first?" asked the very young man. "let me go with loto." they selected the chemist to go first, and all but him took a little of the other drug and checked their growth. the pit at this time was hardly more than fifteen feet across and about thirty feet deep. the chemist stood in the centre of the enclosure, while his friends crowded over against its walls to make room for his growing body. it was nearly half an hour before his head was above its top. he waited only a moment more, then he sprang upwards, clambered out of the pit and disappeared beyond the rim. in a few moments they saw his huge head and shoulders hanging out over the side wall; his hand and arm reached down towards them and they heard his great voice roaring. "come on--somebody else." the very young man went next, with loto. nothing unusual marked their growth, and without difficulty, helped by the chemist's hands reaching down to them, they climbed out of the pit. in an hour more the entire party was in the valley, standing beside the little circular opening out of which they had come. the very young man found himself beside aura, a little apart from the others, who gathered to discuss their plan for growing out of the valley. "it isn't much of a trip, is it, aura?" the very young man said. "do you realize, we're nearly there?" the girl looked around her curiously. the valley of the scratch appeared to them now hardly more than a quarter of a mile in width. aura stared upwards between its narrow walls to where, several thousand feet above, a narrow strip of gray-blue sky was visible. "that sky--is that the sky of your world?" she exclaimed. "how pretty it is!" the very young man laughed. "no, aura, that's not our sky. it's only the space in the room above the ring. when we get the size we are going to be finally, our heads will be right up in there. the real sky with its stars will be even then as far above us as your sky at arite was above you." aura breathed a long sigh. "it's too wonderful--really to understand, isn't it?" she said. the very young man pulled her down on the ground beside him. "the most wonderful part, aura, is going to be having you up there." he spoke gently; somehow whenever he thought of this fragile little girl-woman up in his strange bustling world, he felt himself very big and strong. he wanted to be her protector, and her teacher of all the new and curious things she must learn. the girl did not reply at once; she simply met his earnest gaze with her frank answering smile of understanding. the chemist was calling to them. "oh, you jack. we're about ready to start." the very young man got to his feet, holding down his hands to help aura up. "you're going to make a fine woman, aura, in this new world. you just wait and see if you don't," he said as they rejoined the others. the chemist explained his plans to them. "this valley is several times deeper than its breadth; you can see that. we cannot grow large enough to jump out as we did out of the pit; we would be crushed by the walls before we were sufficiently tall to leap out. "but we're not going to do as i did, and climb all the way up. instead we will stay here at the bottom until we are as large as we can conveniently get between the valley walls. then we will stop growing and climb up the side; it will only be a short distance then." the very young man nodded his comprehension. "unless by that time the walls are too smooth to climb up," he remarked. "if we see them getting too smooth, we'll stop and begin climbing," the chemist agreed. "we're all ready, aren't we?" he began measuring out the estimated quantities of the drug, handing it to each of them. "say, i'm terrible sorry," began the very young man, apologetically interrupting this procedure. "but you know if it wasn't for me, we'd all starve to death." it was several hours since they had eaten last, and all of them were hungry, although the excitement of their strange journey had kept them from realizing it. they ate--"the last meal in the ring" as the big business man put it--and in half an hour more they were ready to start. when they had reached a size where it seemed desirable again to stop growing the valley resembled a narrow cañon--hardly more than a deep rift in the ground. they were still standing on its floor; above them, the parallel edges of the rift marked the surface of the ring. the side walls of the cañon were smooth, but there were still many places where they could climb out without much difficulty. they started up a narrow declivity along the cañon face. the chemist led the way; the very young man, with aura just in front of him, was last. they had been walking only a moment when the chemist called back over his shoulder. "it's getting very narrow. we'd better stop here and take the drug." the chemist had reached a rocky shelf--a ledge some twenty feet square that jutted out from the cañon wall. they gathered upon it, and took enough of the diminishing drug to stop their growth. then the chemist again started forward; but, very soon after, a cry of alarm from aura stopped him. the party turned in confusion and crowded back. aura, pale and trembling, was standing on the very brink of the ledge looking down. the very young man had disappeared. the big business man ran to the brink. "did he fall? where is he? i don't see him." they gathered in confusion about the girl. "no," she said. "he--just a moment ago he was here." "he couldn't have fallen," the doctor exclaimed. "it isn't far down there--we'd see him." the truth suddenly dawned on the doctor. "don't move!" he commanded sharply. "don't any of you move! don't take a step!" uncomprehending, they stood motionless. the doctor's gaze was at the rocky floor under his feet. "it's size," he added vehemently. "don't you understand? he's taken too much of the diminishing drug." an exclamation from oteo made them all move towards him, in spite of the doctor's command. there, close by oteo's feet, they saw the tiny figure of the very young man, already no more than an inch in height, and rapidly growing smaller. the doctor bent down, and the little figure waved its arms in terror. "don't get smaller," called the doctor. but even as he said it, he realized it was a futile command. the very young man answered, in a voice so minute it seemed coming from an infinite distance. "i can't stop! i haven't any of the other drug!" they all remembered then. targo had stolen the very young man's vial of the enlarging drug. it had never been replaced. instead the very young man had been borrowing from the others as he went along. the big business man was seized with sudden panic. "he'll get lost. we must get smaller with him." he turned sidewise, and stumbling over a rock almost crushed the very young man with the step he took to recover his balance. aura, with a cry, pushed several of the others back; oteo and eena, frightened, started down the declivity. "we must get smaller!" the big business man reiterated. the panic was growing among them all. above their excited cries the doctor's voice rose. "stand still--all of you. if we move--even a few steps--we can never get small and hope to find him." the doctor--himself too confused to know whether he should take the diminishing drug at once or not--was bending over the ground. and as he watched, fascinated, the very young man's figure dwindled beyond the vanishing point and was gone! chapter xxxix a modern dinosaur the very young man never knew quite how it happened. the doctor had told them to check their growth: and he took the drug abstractedly, for his mind was on aura and how she would feel, coming for the first time into this great outer world. what quantity he took, the very young man afterward could never decide. but the next thing he knew, the figures of his companions had grown to gigantic size. the rocks about him were expanding enormously. already he had lost the contour of the ledge. the cañon wall had drawn back almost out of sight in the haze of the distance. he turned around, bewildered. there was no precipice behind him. instead, a great, rocky plain, tumbling with a mass of boulders, and broken by seams and rifts, spread out to his gaze. and even in that instant, as he regarded it in confusion, it opened up to greater distances. near at hand--a hundred yards away, perhaps--a gigantic human figure towered five hundred feet into the air. around it, further away, others equally large, were blurred into the haze of distance. the nearer figure stooped, and the very young man, fearful that he might be crushed by its movement, waved his arms in terror. he started to run, leaping over the jagged ground beneath his feet. a great roaring voice from above came down to him--the doctor's voice. "don't get smaller!" the very young man stopped running, more frightened than ever before with the realization that came to him. he shouted upward: "i can't stop! i haven't any of the other drug!" an enormous blurred object came swooping towards him, and went past with a rush of wind--the foot of the big business man, though the very young man did not know it. above him now the air was filled with roaring--the excited voices of his friends. a few moments passed while the very young man stood stock still, too frightened to move. the roaring above gradually ceased. the towering figures expanded--faded back into the distance--disappeared. the very young man was alone in the silence and desolation of a jagged, broken landscape that was still expanding beneath him. for some time he stood there, bewildered. he came to himself suddenly with the thought that although he was too small to be seen by his friends, yet they must be there still within a few steps of him. they might take a step--might crush him to death without seeing him, or knowing that they had done it! there were rocky buttes and hills all about him now. without stopping to reason what he was doing he began to run. he did not know or care where--anywhere away from those colossal figures who with a single step would crush the very hills and rocks about him and bury him beneath an avalanche of golden quartz. he ran, in panic, for an hour perhaps, scrambling over little ravines, falling into a crevice--climbing out and running again. at last, with his feet torn and bleeding, he threw himself to the ground, utterly exhausted. after a time, with returning strength, the very young man began to think more calmly. he was lost--lost in size--the one thing that the doctor, when they started down into the ring, had warned them against so earnestly. what a fool he had been to run! he was miles away from them now. he could not make himself large; and were they to get smaller--small enough to see him, they might wander in this barren wilderness for days and never chance to come upon him. the very young man cursed himself for a fool. why hadn't he kept some of the enlarging drug with him? and then abruptly, he realized something additionally terrifying. the dose of the diminishing drug which he had just taken so thoughtlessly, was the last that remained in that vial. he was utterly helpless. thousands of miles of rocky country surrounded him--a wilderness devoid of vegetation, of water, and of life. lying prone upon the ground, which at last had stopped expanding, the very young man gave himself up to terrified reflection. so this was the end--all the dangers they had passed through--their conquests--and the journey out of the ring so near to a safe ending.... and then this! for a time the very young man abandoned hope. there was nothing to do, of course. they could never find him--probably, with women and a child among them they would not dare even to try. they would go safely back to their own world--but he--jack bruce--would remain in the ring. he laughed with bitter cynicism at the thought. even the habitable world of the ring itself, was denied him. like a lost soul, poised between two worlds, he was abandoned, waiting helpless, until hunger and thirst would put an end to his sufferings. then the very young man thought of aura; and with the thought came a new determination not to give up hope. he stood up and looked about him, steeling himself against the flood of despair that again was almost overwhelming. he must return as nearly as possible to the point where he had parted from his friends. it was the only chance he had remaining--to be close enough so if one, or all of them, had become small, they would be able to see him. there was little to choose of direction in the desolate waste around, but dimly the very young man recalled having a low line of hills behind him when he was running. he faced that way now. he had come perhaps six or seven miles; he would return now as nearly as possible over the same route. he selected a gully that seemed to wind in that general direction, and climbing down into it, started off along its floor. the gully was some forty feet deep and seemed to average considerably wider. its sides were smooth and precipitous in some places; in others they were broken. the very young man had been walking some thirty minutes when, as he came abruptly around a sharp bend, he saw before him the most terrifying object he had ever beheld. he stood stock still, fascinated with horror. on the floor of the gully, directly in front of him, lay a gigantic lizard--a reptile hideous, grotesque in its enormity. it was lying motionless, with its jaw, longer than his own body, flat on the ground as though it were sunning itself. its tail, motionless also, wound out behind it. it was a reptile that by its size--it seemed to the very young man at least thirty feet long--might have been a dinosaur reincarnated out of the dark, mysterious ages of the earth's formation. and yet, even in that moment of horror, the very young man recognized it for what it was--the tiny lizard the chemist had sent into the valley of the scratch to test his drug! at sight of the very young man the reptile raised its great head. its tongue licked out hideously; its huge eyes stared unblinking. and then, slowly, hastelessly, it began coming forward, its great feet scratching on the rocks, its tail sliding around a boulder behind it. the very young man waited no longer, but turning, ran back headlong the way he had come. curiously enough, this new danger, though it terrified, did not confuse him. it was a situation demanding physical action, and with it he found his mind working clearly. he leaped over a rock, half stumbled, recovered himself and dashed onward. a glance over his shoulder showed him the reptile coming around the bend in the gully. it slid forward, crawling over the rocks without effort, still hastelessly, as though leisurely to pick up this prey which it knew could not escape it. the gully here chanced to have smooth, almost perpendicular sides. the very young man saw that he could not climb out; and even if he could, he knew that the reptile would go up the sides as easily as along the floor. it had been over a hundred feet from him when he first saw it. now it was less than half that distance and gaining rapidly. for an instant the very young man slackened his flight. to run on would be futile. the reptile would overtake him any moment; even now he knew that with a sudden spring it could land upon him. a cross rift at right angles in the wall came into sight--a break in the rock as though it had been riven apart by some gigantic wedge. it was as deep as the gully itself and just wide enough to admit the passage of the very young man's body. he darted into it; and heard behind him the spring of the reptile as it landed at the entrance to the rift into which its huge size barred it from advancing. the very young man stopped--panting for breath. he could just turn about between the enclosing walls. behind him, outside in the gully, the lizard lay baffled. and then, seemingly without further interest, it moved away. the very young man rested. the danger was past. he could get out of the rift, doubtless, further ahead, without reentering the gully. and, if he kept well away from the reptile, probably it would not bother him. exultation filled the very young man. and then again he remembered his situation--lost in size, helpless, without the power to rejoin his friends. he had escaped death in one form only to confront it again in another--worse perhaps, since it was the more lingering. ahead of him, the rift seemed ascending and opening up. he followed it, and in a few hundred yards was again on the broken plateau above, level now with the top of the gully. the winding gully itself, the very young man could see plainly. its nearest point to him was some six hundred feet away; and in its bottom he knew that hideous reptile lurked. he shuddered and turned away, instinctively walking quietly, fearing to make some noise that might again attract its attention to him. and then came a sound that drove the blood from his face and turned him cold all over. from the depths of the gully, in another of its bends nearby, the sound of an anxious girl's voice floated upward. "jack! oh jack!" and again: "jack--my friend jack!" it was aura, his own size perhaps, in the gully searching for him! with frantic, horrified haste, the very young man ran towards the top of the gully. he shouted warningly, as he ran. aura must have heard him, for her voice changed from anxiety to a glad cry of relief. he reached the top of the gully; at its bottom--forty feet below down its precipitous side--stood aura, looking up, radiant, to greet him. "i took the drug," she cried. "i took it before they could forbid me. they are waiting--up there for us. there is no danger now, jack." the very young man tried to silence her. a noise down the gully made him turn. the gigantic reptile appeared round the nearby bend. it saw the girl and scuttled forward, rattling the loose bowlders beneath its feet as it came. aura saw it the same instant. she looked up helplessly to the very young man above her; then she turned and ran down the gully. the very young man stood transfixed. it was a sheer drop of forty feet or more to the gully floor beneath him. there was seemingly nothing that he could do in those few terrible seconds, and yet with subconscious, instinctive reasoning, he did the one and only thing possible. a loose mass of the jagged, gold quartz hung over the gully wall. frantically he tore at it--pried loose with feet and hands a bowlder that hung poised. as the lizard approached, the loosened rock slid forward, and dropped squarely upon the reptile's broad back. it was a bowlder nearly as large as the very young man himself, but the gigantic reptile shook it off, writhing and twisting for an instant, and hurling the smaller loose rocks about the floor of the gully with its struggles. the very young man cast about for another missile, but there were none at hand. aura, at the confusion, had stopped about two hundred feet away. "run!" shouted the very young man. "hide somewhere! run!" the lizard, momentarily stunned, recovered swiftly. again it started forward, seemingly now as alert as before. and then, without warning, in the air above his head the very young man heard the rush of gigantic wings. a tremendous grey body swooped past him and into the gully--a bird larger in proportion than the lizard itself.... it was the little sparrow the chemist had sent in from the outside world--maddened now by thirst and hunger, which to the reptile had been much more endurable. the very young man, shouting again to aura to run, stood awestruck, watching the titanic struggle that was raging below him. the great lizard rose high on its forelegs to meet this enemy. its tremendous jaws opened--and snapped closed; but the bird avoided them. its huge claws gripped the reptile's back; its flapping wings spread the sixty foot width of the gully as it strove to raise its prey into the air. the roaring of these enormous wings was deafening; the wind from them as they came up tore past the very young man in violent gusts; and as they went down, the suction of air almost swept him over the brink of the precipice. he flung himself prone, clinging desperately to hold his position. the lizard threshed and squirmed. a swish of its enormous tail struck the gully wall and brought down an avalanche of loose, golden rock. but the giant bird held its grip; its bill--so large that the very young man's body could easily have lain within it--pecked ferociously at the lizard's head. it was a struggle to the death--an unequal struggle, though it raged for many minutes with an uncanny fury. at last, dragging its adversary to where the gully was wider, the bird flapped its wings with freedom of movement and laboriously rose into the air. and a moment later the very young man, looking upward, saw through the magic diminishing glass of distance, a little sparrow of his own world, with a tiny, helpless lizard struggling in its grasp. * * * * * "aura! don't cry, aura! gosh, i don't want you to cry--everything's all right now." the very young man sat awkwardly beside the frightened girl, who, overcome by the strain of what she had been through, was crying silently. it was strange to see aura crying; she had always been such a spartan, so different from any other girl he had ever known. it confused him. "don't cry, aura," he repeated. he tried clumsily to soothe her. he wanted to thank her for what she had done in risking her life to find him. he wanted to tell her a thousand tender things that sprang into his heart as he sat there beside her. but when she raised her tear-stained face and smiled at him bravely, all he said was: "gosh, that was some fight, wasn't it? it was great of you to come down after me, aura. are they waiting for us up there?" and then when she nodded: "we'd better hurry, aura. how can we ever find them? we must have come miles from where they are." she smiled at him quizzically through her tears. "you forget, jack, how small we are. they are waiting on the little ledge for us--and all this country--" she spread her arms toward the vast wilderness that surrounded them--"this is all only a very small part of that same ledge on which they are standing." it was true; and the very young man realized it at once. aura had both drugs with her. they took the one to increase their size, and without mishap or moving from where they were, rejoined those on the little ledge who were so anxiously awaiting them. for half an hour the very young man recounted his adventure, with praises of aura that made the girl run to her sister to hide her confusion. then once more the party started its short climb out of the valley of the scratch. in ten minutes they were all safely on the top--on the surface of the ring at last. chapter xl the adventurers' return the banker, lying huddled in his chair in the clubroom, awoke with a start. the ring lay at his feet--a shining, golden band gleaming brightly in the light as it lay upon the black silk handkerchief. the banker shivered a little for the room was cold. then he realized he had been asleep and looked at his watch. three o'clock! they had been gone seven hours, and he had not taken the ring back to the museum as they had told him to. he rose hastily to his feet; then as another thought struck him, he sat down again, staring at the ring. the honk of an automobile horn in the street outside aroused him from his reverie. he got to his feet and mechanically began straightening up the room, packing up the several suit-cases. then with obvious awe, and a caution that was almost ludicrous, he fixed the ring in its frame within the valise prepared for it. he lighted the little light in the valise, and, every moment or two, went back to look searchingly down at the ring inside. when everything was packed the banker left the room, returning in a moment with two of the club attendants. they carried the suit-cases outside, the banker himself gingerly holding the bag containing the ring. "a taxi," he ordered when they were at the door. then he went to the desk, explaining that his friends had left earlier in the evening and that they had finished with the room. to the taxi-driver he gave a number that was not the museum address, but that of his own bachelor apartment on park avenue. it was still raining as he got into the taxi; he held the valise tightly on his lap, looking into it occasionally and gruffly ordering the chauffeur to drive slowly. in the sumptuous living-room of his apartment he spread the handkerchief on the floor under the center electrolier and laid the ring upon it. dismissing the astonished and only half-awake butler with a growl, he sat down in an easy-chair facing the ring, and in a few minutes more was again fast asleep. in the morning when the maid entered he was still sleeping. two hours later he rang for her, and gave tersely a variety of orders. these she and the butler obeyed with an air that plainly showed they thought their master had taken leave of his senses. they brought him his breakfast and a bath-robe and slippers. and the butler carried in a mattress and a pair of blankets, laying them with a sigh on the hardwood floor in a corner of the room. then the banker waved them away. he undressed, put on his bath-robe and slippers and sat down calmly to eat his breakfast. when he had finished he lighted a cigar and sat again in his easy-chair, staring at the ring, engrossed with his thoughts. three days he would give them. three days, to be sure they had made the trip successfully. then he would take the ring to the museum. and every sunday he would visit it; until they came back--if they ever did. * * * * * the banker's living-room with its usually perfect appointments was in thorough disorder. his meals were still being served him there by his dismayed servants. the mattress still lay in the corner; on it the rumpled blankets showed where he had been sleeping. for the hundredth time during his long vigil the banker, still wearing his dressing-gown and slippers and needing a shave badly, put his face down close to the ring. his heart leaped into his throat; his breath came fast; for along the edge of the ring a tiny little line of figures was slowly moving. he looked closer, careful lest his laboured breathing blow them away. he saw they were human forms--little upright figures, an eighth of an inch or less in height--moving slowly along one behind the other. he counted nine of them. nine! he thought, with a shock of surprise. why, only three had gone in! then they had found rogers, and were bringing him and others back with him! relief from the strain of many hours surged over the banker. his eyes filled with tears; he dashed them away--and thought how ridiculous a feeling it was that possessed him. then suddenly his head felt queer; he was afraid he was going to faint. he rose unsteadily to his feet, and threw himself full-length upon the mattress in the corner of the room. then his senses faded. he seemed hardly to faint, but rather to drift off into an involuntary but pleasant slumber. * * * * * with returning consciousness the banker heard in the room a confusion of many voices. he opened his eyes; the doctor was sitting on the mattress beside him. the banker smiled and parted his lips to speak, but the doctor interrupted him. "well, old friend!" he cried heartily. "what happened to you? here we are back all safely." the banker shook his friend's hand with emotion; then after a moment he sat up and looked about him. the room seemed full of people--strange looking figures, in extraordinary costumes, dirty and torn. the very young man crowded forward. "we got back, sir, didn't we?" he said. the banker saw he was holding a young girl by the hand--the most remarkable-looking girl, the banker thought, that he had ever beheld. her single garment, hanging short of her bare knees, was ragged and dirty; her jet black hair fell in tangled masses over her shoulders. "this is aura," said the very young man. his voice was full of pride; his manner ingenuous as a child's. without a trace of embarrassment the girl smiled and with a pretty little bending of her head, held down her hand to the astonished banker, who sat speechless upon his mattress. loto pushed forward. "that's _mamita_ over there," he said, pointing. "her name is lylda; she's aura's sister." the banker recovered his wits. "well, and who are you, little man?" he asked with a smile. "my name is loto," the little boy answered earnestly. "that's my father." and he pointed across the room to where the chemist was coming forward to join them. chapter xli the first christmas christmas eve in a little village of northern new york--a white christmas, clear and cold. in the dark, blue-black of the sky the glittering stars were spread thick; the brilliant moon poured down its silver light over the whiteness of the sloping roof-tops, and upon the ghostly white, silently drooping trees. a heaviness hung in the frosty air--a stillness broken only by the tinkling of sleigh-bells or sometimes by the merry laughter of the passers-by. at the outskirts of the village, a little back from the road, a farmhouse lay snuggled up between two huge apple-trees--an old-fashioned, rambling farmhouse with a steeply pitched roof, piled high now, with snow. it was brilliantly lighted this christmas eve, its lower windows sending forth broad yellow beams of light over the whiteness of the ground outside. in one of the lower rooms of the house, before a huge, blazing log-fire, a woman and four men sat talking. across the room, at a table, a little boy was looking at a picture-book by the light of an oil-lamp. the woman made a striking picture as she sat back at ease before the fire. she was dressed in a simple black evening-dress such as a lady of the city would wear. it covered her shoulders, but left her throat bare. her features, particularly her eyes, had a slight oriental cast, which the mass of very black hair coiled on her head accentuated. yet she did not look like an oriental, nor indeed like a woman of any race of this earth. her cheeks were red--the delicate diffused red of perfect health. but underneath the red there lay a curious mixture of other colours, not only on her cheeks but particularly noticeable on her neck and arms. her skin was smooth as a pearl; in the mellow firelight it glowed, with the iridescence of a shell. the four men were dressed in the careless negligee of city men in the country. they were talking gaily now among themselves. the woman spoke seldom, staring dreamily into the fire. a clock in another room struck eight; the woman glanced over to where the child sat, absorbed with the pictures in his book. the page at which he was looking showed a sleigh loaded with toys, with a team of reindeers and a jolly, fat, white-bearded, red-jacketed old man driving the sleigh over the chimney tops. "come loto, little son," the woman said. "you hear--it is the time of sleep for you." the boy put down his book reluctantly and went over to the fireplace, standing beside his mother with an arm about her neck. "oh, _mamita_ dear, will he surely come, this santa claus? he never knew about me before; will he surely come?" lylda kissed him tenderly. "he will come, loto, every christmas eve; to you and to all the other children of this great world, will he always come." "but you must be asleep when he comes, loto," one of the men admonished. "yes, my father, that i know," the boy answered gravely. "i will go now." "come back loto, when you have undressed," the chemist called after him, as he left the room. "remember you must hang your stocking." when they were left alone lylda looked at her companions and smiled. "his first christmas," she said. "how wonderful we are going to make it for him." "i can remember so well," the big business man remarked thoughtfully, "when they first told me there was no santa claus. i cried, for i knew christmas would never be the same to me." "loto is nearly twelve years old," the doctor said. "just imagine--having his first christmas." "we're going to make it a corker," said the banker. "where's the tree? we got one." "in the wood-shed," lylda answered. "he has not seen it; i was so very careful." they were silent a moment. then: "my room is chock full of toys," the banker said reflectively. "but this is a rotten town for candy canes--they only had little ones." and they all laughed. "i have a present for you, lylda," the chemist said after a moment. "oh, but you must not give it until to-morrow; you yourself have told me that." the chemist rose. "i want to give it now," he said, and left the room. in a moment he returned, carrying a mahogany pedestal under one arm and a square parcel in the other. he set the pedestal upright on the floor in a corner of the room and began opening the package. it was a mahogany case, cubical in shape. he lifted its cover, disclosing a glass-bell set upon a flat, mahogany slab. fastened to the center of this was a handsome black plush case, in which lay a gold wedding-ring. lylda drew in her breath sharply and held it; the three other men stared at the ring in amazement. the chemist was saying: "and i decided not to destroy it, lylda, for your sake. there is no air under this glass cover; the ring is lying in a vacuum, so that nothing can come out of it and live. it is quite safe for us to keep it--this way. i thought of this plan, afterwards, and decided to keep the ring--for you." he set the glass bell on the pedestal. lylda stood before it, bending down close over the glass. "you give me back--my world," she breathed; then she straightened up, holding out her arms toward the ring. "my birthplace--my people--they are safe." and then abruptly she sank to her knees and began softly sobbing. loto called from upstairs and they heard him coming down. lylda went back hastily to the fire; the chemist pushed a large chair in front of the pedestal, hiding it from sight. the boy, in his night clothes, stood on the hearth beside his mother. "there is the stocking, _mamita_. where shall i hang it?" "first the prayer, loto. can you remember?" the child knelt on the hearth, with his head in his mother's lap. "now i lay me----" he began softly, halting over the unfamiliar words. lylda's fingers stroked his brown curly head as it nestled against her knees; the firelight shone golden in his tousled curls. the chemist was watching them with moist eyes. "his first christmas," he murmured, and smiled a little tender smile. "his first christmas." the child was finishing. "and god bless aura, and jack, and----" "and grandfather reoh," his mother prompted softly. "and grandfather reoh--and _mamita_, and----" the boy ended with a rush--"and me too. amen. now where do i hang the stocking, mother?" in a moment the little stocking dangled from a mantel over the fireplace. "you are sure he will come?" the child asked anxiously again. "it is certain, loto--if you are asleep." loto kissed his mother and shook hands solemnly with the men--a grave, dignified little figure. "good night, loto," said the big business man. "good night, sir. good night, my father--good night, _mamita_; i shall be asleep very soon." and with a last look at the stocking he ran out of the room. "what a christmas he will have," said the banker, a little huskily. a girl stood in the doorway that led into the dining-room adjoining--a curious-looking girl in a gingham apron and cap. lylda looked up. "oh, eena, please will you say to oteo we want the tree from the wood-shed--in the dining-room." the little maid hesitated. her mistress smiled and added a few words in foreign tongue. the girl disappeared. "every window gets a holly wreath," the doctor said. "they're in a box outside in the wood-shed." "look what i've got," said the big business man, and produced from his pocket a little folded object which he opened triumphantly into a long serpent of filigree red paper on a string with little red and green paper bells hanging from it. "across the doorway," he added, waving his hand. a moment after there came a stamping of feet on the porch outside, and then the banging of an outer door. a young man and girl burst into the room, kicking the snow from their feet and laughing. the youth carried two pairs of ice-skates slung over his shoulder; as he entered the room he flung them clattering to the floor. the girl, even at first glance, was extraordinarily pretty. she was small and very slender of build. she wore stout high-laced tan shoes, a heavy woollen skirt that fell to her shoe-tops and a short, belted coat, with a high collar buttoned tight about her throat. she was covered now with snow. her face and the locks of hair that strayed from under her knitted cap were soaking wet. "he threw me down," she appealed to the others. "i didn't--she fell." "you did; into the snow you threw me--off the road." she laughed. "but i am learning to skate." "she fell three times," said her companion accusingly. "twice only, it was," the girl corrected. she pulled off her cap, and a great mass of black hair came tumbling down about her shoulders. lylda, from her chair before the fire, smiled mischievously. "aura, my sister," she said in a tone of gentle reproof. "so immodest it is to show all that hair." the girl in confusion began gathering it up. "don't you let her tease you, aura," said the big business man. "it's very beautiful hair." "where's loto?" asked the very young man, pulling off his hat and coat. "in bed--see his stocking there." a childish treble voice was calling from upstairs. "good night, aura--good night, my friend jack." "good night, old man--see you to-morrow," the very young man called back in answer. "you mustn't make so much noise," the doctor said reprovingly. "he'll never get to sleep." "no, you mustn't," the big business man agreed. "to-morrow's a very very big day for him." "some christmas," commented the very young man looking around. "where's the holly and stuff?" "oh, we've got it all right, don't you worry," said the banker. "and mistletoe," said lylda, twinkling. "for you, jack." eena again stood in the doorway and said something to her mistress. "the tree is ready," said lylda. the chemist rose to his feet. "come on, everybody; let's go trim it." they crowded gaily into the dining-room, leaving the very young man and aura sitting alone by the fire. for some time they sat silent, listening to the laughter of the others trimming the tree. the very young man looked at the girl beside him as she sat staring into the fire. she had taken off her heavy coat, and her figure seemed long and very slim in the clothes she was wearing now. she sat bending forward, with her hands clasped over her knees. the long line of her slender arm and shoulder, and the delicacy of her profile turned towards him, made the very young man realize anew how fragile she was, and how beautiful. her mass of hair was coiled in a great black pile on her head, with a big, loose knot low at the neck. the iridescence of her skin gleamed under the flaming red of her cheeks. her lips, too, were red, with the smooth, rich red of coral. the very young man thought with a shock of surprise that he had never noticed before that they were red; in the ring there had been no such color. in the room adjoining, his friends were proposing a toast over the christmas punch bowl. the chemist's voice floated in through the doorway. "to the oroids--happiness to them." then for an instant there was silence as they drank the toast. aura met the very young man's eyes and smiled a little wanly. "happiness--to them! i wonder. we who are so happy to-night--i wonder, are they?" the very young man leaned towards her. "you are happy, aura?" the girl nodded, still staring wistfully into the fire. "i want you to be," the very young man added simply, and fell silent. a blazing log in the fire twisted and rolled to one side; the crackling flames leaped higher, bathing the girl's drooping little figure in their golden light. the very young man after a time found himself murmuring familiar lines of poetry. his memory leaped back. a boat sailing over a silent summer lake--underneath the stars--the warmth of a girl's soft little body touching his--her hair, twisted about his fingers--the thrill in his heart; he felt it now as his lips formed the words: "the stars would be your pearls upon a string, the world a ruby for your finger-ring, and you could have the sun and moon to wear, if i were king." "you remember, aura, that night in the boat?" again the girl nodded. "i shall learn to read it--some day," she said eagerly. "and all the others that you told me. i want to. they sing--so beautifully." a sleigh passed along the road outside; the jingle of its bells drifted in to them. the very young man reached over and gently touched the girl's hand; her fingers closed over his with an answering pressure. his heart was beating fast. "aura," he said earnestly. "i want to be king--for you--this first christmas and always. i want to give you--all there is in this life, of happiness, that i can give--just for you." the girl met his gaze with eyes that were melting with tenderness. "i love you, aura," he said softly. "i love you, too, jack," she whispered, and held her lips up to his. transcribed from the cassell & company edition by david price, email ccx @coventry.ac.uk consolations in travel; or, the last days of a philosopher. by sir humphry davy, bart., _late president of the royal society_. cassell & company, limited: _london, paris, new york & melbourne_. introduction. humphry davy was born at penzance, in cornwall, on the th of december, , and died at geneva on the th of may, , at the age of fifty. he was a philosopher who turned knowledge to wisdom; he was one of the foremost of our english men of science; and this book, written when he was dying, which makes reason the companion of faith, shows how he passed through the light of earth into the light of heaven. his father had a small patrimony at varfell, in ludgvan. his mother had lost in early childhood both her parents within a few hours of each other, and had been adopted by john tonkin, an eminent surgeon in penzance, to whom, therefore, so to speak, humphry davy became grandson by adoption. there were five such grandchildren--humphry, the elder of two boys, the other boy being named john, and three girls. at a preparatory school and at the penzance grammar school humphry davy was a noticeable boy. he read eagerly and showed great quickness of imagination, delighted in legends, when eight years old told stories to his companions, and as a boy wrote verse. there was a quaker saddler who made for himself an electrical machine and mechanical models, in which young davy took keen interest, and from that saddler, robert dunkin, came the first impulse towards experiments in science. at fifteen davy was placed for further education at a school in truro. a year later his father died, and john tonkin apprenticed him, on the th of february, , to dr. borlase, a surgeon in large practice at penzance. medical practitioners in those days dispensed their own medicines, and the inquiring mind of this young apprentice being let loose upon a store-room of chemicals, experimental chemistry became his favourite pursuit. his grandfather, by adoption, allowed him to fit up a garret as a laboratory, notwithstanding the fears of the household that "this boy, humphry, will blow us all into the air." activity and originality of mind, with a persistent habit of inquiry and experiment, brought davy friends who could appreciate and help him. when dr. beddoes, of bristol, was examining the cornish coast, in , he came upon young humphry davy, was told of researches made by him, and urged to engage him as laboratory assistant in a pneumatic institution that he was then establishing in bristol. davy went in october, , then in his twentieth year; but his good friend, and grandfather by adoption, had set his heart upon humphry's becoming an eminent burgeon, and even altered his will when his boy yielded to the temptation of a laboratory for research. men also know something of the trouble of the hen who has a chance duckling in her brood, and sees that contumacious chicken run into the water deaf to all the warnings of her love. at bristol humphry davy came into companionship with coleridge and southey, who were then also at the outset of their career, and there are poems of his in the poetical anthology then published by southey. but at the same time davy contributed papers on "heat, light, and the combinations of light," on "phos-oxygen and its combinations," and on "the theory of respiration," to a volume of west country collections, that filled more than half the volume. he was experimenting then on gases and on galvanism, and one day by experiment upon himself, in the breathing of carburetted hydrogen, he almost put an end to his life. in count rumford was founding the royal institution, and its home in albemarle street was then bought for it. the first lecturer appointed was in bad health, and in he was obliged to resign. young davy was now known to men of science for the number and freshness of his experiments, and for the substantial value of his chemical discoveries. it was resolved by the managers, in july, , that humphry davy be appointed assistant-lecturer in chemistry, director of the chemical laboratory, and assistant-editor of the journals of the royal institution. his first remuneration was a room in the house, coals and candles, and pounds a year. count rumford held out the prospect of a professorship with pounds a year, and the certainty of full support in the use of the laboratory for his own private research. his age then was twenty-three. he at once satisfied men of science and amused people of fashion. his energy was unbounded; there was a fascination in his personal character and manner. he was a genial and delightful lecturer, and his inventive genius was continually finding something new. a first suggestion of the process of photography was dropped incidentally among the records of researches that attracted more attention. davy had been little more than a year at the royal institution when he was made its professor of chemistry. after another year he was made a fellow. dr. paris, his biographer, says that "the enthusiastic admiration which his lectures obtained is at this period scarcely to be imagined. men of the first rank and talent--the literary and the scientific, the practical, the theoretical--blue-stockings and women of fashion, the old and the young, all crowded--eagerly crowded--the lecture-room." at the beginning of the year his salary was raised to pounds a year. in may of that year the royal society awarded to him the copley medal. within the next two years he was elected secretary of the royal society. since he had been advancing knowledge by experiments with galvanism. the royal institution raised a special fund to place at his disposal a more powerful galvanic battery than any that had been constructed. the fame of his discoveries spread over europe. the institute of france gave davy the napoleon prize of three thousand francs for the best experiments in galvanism. dublin, in , paid davy four hundred guineas for some lectures upon his discoveries. the farming society of ireland gave him pounds for six lectures on chemistry applied to agriculture. in the following year he received more than a thousand pounds for two courses of lectures at dublin, and was sent home with the honorary degree of ll.d. in april, , he was knighted, resigned his professorship at the royal institution, and "in order more strongly to mark the high sense of his merits" he was elected honorary professor of chemistry. in the same month davy married a young and rich widow, who had charmed all edinburgh by her beauty and her wit. two months after marriage sir humphry davy dedicated to his wife his "elements of chemical philosophy." in march, , he published his "elements of agricultural chemistry." he travelled abroad, and was received with honour by the chief men of science in all places that he visited. when, at pavia, he first met volta: he found that volta had put on full-dress to receive him. in august, , davy's attention was drawn to the loss of life by explosions of fire-damp, and by the end of the year he had devised his safety-lamp. the coal owners subscribed , pounds for a testimonial, gave him also a dinner and a service of plate. in october, , he was made a baronet. in november, , he was elected president of the royal society. his next researches were chiefly on electro-magnetism and the protection of the copper sheathing on ships' bottoms. at the end of his health failed seriously. he went to italy; resigned, in july, , the presidency of the royal society; came back to england, longing for "the fresh air of the mountains;" wrote and published his "salmonia, or days of fly-fishing." in the spring of he left england again. he was at rome in the winter of , still engaged in quiet research, and it was then that he wrote his "consolations in travel; or, the last days of a philosopher." his wife, who shone in london society, did not go with him upon this last journey, but travelled day and night to reach him when word came to her and to his brother john, who was a physician, that he had again been struck with palsy and was dying. that stroke of palsy followed immediately upon the finishing of the book now in the reader's hand. davy lived to see again his wife and brother, rallied enough to leave rome with them, and had got as far as geneva on the th of may, . he died in the next night. h. m. a note, _prefixed to the first edition, by sir humphry davy's brother_. as is stated in the preface which follows, this work was composed during a period of bodily indisposition;--it was concluded at the very moment of the invasion of the author's last illness. had his life been prolonged, it is probable that some additions and some changes would have been made. the editor does not consider himself warranted to do more than give to the world a faithful copy, making only a few omissions and a few verbal alterations. the characters of the persons of the dialogue were intended to be ideal, at least in great part such they should be considered by the reader; and, it is to be hoped, that the incidents introduced, as well as the persons, will be viewed only as subordinate and subservient to the sentiments and doctrines. the dedication, it may be specially noticed, is the author's own, and in the very words dictated by him, at a time when he had lost the power of writing except with extreme difficulty, owing to the paralytic attack, although he retained in a very remarkable manner all his mental faculties unimpaired and unclouded. john davy. _london_, _january th_, . to thomas poole, esq. of nether stowey in remembrance of thirty years of continued and faithful friendship. author's preface. salmonia was written during the time of a partial recovery from a long and dangerous illness. the present work was composed immediately after, under the same unfavourable and painful circumstances, and at a period when the constitution of the author suffered from new attacks. he has derived some pleasure and some consolation, when most other sources of consolation and pleasure were closed to him, from this exercise of his mind; and he ventures to hope that these hours of sickness may be not altogether unprofitable to persons in perfect health. _rome_, _february_ , . dialogue the first. the vision. i passed the autumn and the early winter of the years -- and -- at rome. the society was, as is usual in that metropolis of the old christian world, numerous and diversified. in it there were found many intellectual foreigners and amongst them some distinguished britons, who had a higher object in making this city their residence than mere idleness or vague curiosity. amongst these my countrymen, there were two gentlemen with whom i formed a particular intimacy and who were my frequent companions in the visits which i made to the monuments of the grandeur of the old romans and to the masterpieces of ancient and modern art. one of them i shall call ambrosio: he was a man of highly cultivated taste, great classical erudition, and minute historical knowledge. in religion he was of the roman catholic persuasion; but a catholic of the most liberal school, who in another age might have been secretary to ganganelli. his views upon the subjects of politics and religion were enlarged; but his leaning was rather to the power of a single magistrate than to the authority of a democracy or even of an oligarchy. the other friend, whom i shall call onuphrio, was a man of a very different character. belonging to the english aristocracy, he had some of the prejudices usually attached to birth and rank; but his manners were gentle, his temper good, and his disposition amiable. having been partly educated at a northern university in britain, he had adopted views in religion which went even beyond toleration and which might be regarded as entering the verge of scepticism. for a patrician he was very liberal in his political views. his imagination was poetical and discursive, his taste good and his tact extremely fine, so exquisite, indeed, that it sometimes approached to morbid sensibility, and disgusted him with slight defects and made him keenly sensible of small perfections to which common minds would have been indifferent. in the beginning of october on a very fine afternoon i drove with these two friends to the colosaeum, a monument which, for the hundredth time even, i had viewed with a new admiration; my friends partook of my sentiments. i shall give the conversation which occurred there in their own words. onuphrio said, "how impressive are those ruins!--what a character do they give us of the ancient romans, what magnificence of design, what grandeur of execution! had we not historical documents to inform us of the period when this structure was raised and of the purposes for which it was designed, it might be imagined the work of a race of giants, a council chamber for those titans fabled to have warred against the gods of the pagan mythology. the size of the masses of travertine of which it is composed is in harmony with the immense magnitude of the building. it is hardly to be wondered at that a people which constructed such works for their daily sports, for their usual amusements, should have possessed strength, enduring energy, and perseverance sufficient to enable them to conquer the world. they appear always to have formed their plans and made their combinations as if their power were beyond the reach of chance, independent of the influence of time, and founded for unlimited duration--for eternity!" ambrosio took up the discourse of onuphrio, and said, "the aspect of this wonderful heap of ruins is so picturesque that it is impossible to regret its decay; and at this season of the year the colours of the vegetation are in harmony with those of the falling ruins, and how perfectly the whole landscape is in tone! the remains of the palace of the caesars and of the golden halls of nero appear in the distance, their gray and tottering turrets and their moss-stained arches reposing, as it were, upon the decaying vegetation: and there is nothing that marks the existence of life except the few pious devotees, who wander from station to station in the arena below, kneeling before the cross, and demonstrating the triumph of a religion, which received in this very spot in the early period of its existence one of its most severe persecutions, and which, nevertheless, has preserved what remains of that building, where attempts were made to stifle it almost at its birth; for, without the influence of christianity, these majestic ruins would have been dispersed or levelled to the dust. plundered of their lead and iron by the barbarians, goths, and vandals, and robbed even of their stones by roman princes, the barberini, they owe what remains of their relics to the sanctifying influence of that faith which has preserved for the world all that was worth preserving, not merely arts and literature but likewise that which constitutes the progressive nature of intellect and the institutions which afford to us happiness in this world and hopes of a blessed immortality in the next. and, being of the faith of rome, i may say, that the preservation of this pile by the sanctifying effect of a few crosses planted round it, is almost a miraculous event. and what a contrast the present application of this building, connected with holy feelings and exalted hopes, is to that of the ancient one, when it was used for exhibiting to the roman people the destruction of men by wild beasts, or of men, more savage than wild beasts, by each other, to gratify a horrible appetite for cruelty, founded upon a still more detestable lust, that of universal domination! and who would have supposed, in the time of titus, that a faith, despised in its insignificant origin, and persecuted from the supposed obscurity of its founder and its principles, should have reared a dome to the memory of one of its humblest teachers, more glorious than was ever framed for jupiter or apollo in the ancient world, and have preserved even the ruins of the temples of the pagan deities, and have burst forth in splendour and majesty, consecrating truth amidst the shrines of error, employing the idols of the roman superstition for the most holy purposes and rising a bright and constant light amidst the dark and starless night which followed the destruction of the roman empire!" onuphrio now resumed the discourse. he said, "i have not the same exalted views on the subject which our friend ambrosio has so eloquently expressed. some little of the perfect state in which these ruins exist may have been owing to causes which he has described; but these causes have only lately begun to operate, and the mischief was done before christianity was established at rome. feeling differently on these subjects, i admire this venerable ruin rather as a record of the destruction of the power of the greatest people that ever existed, than as a proof of the triumph of christianity; and i am carried forward in melancholy anticipation to the period when even the magnificent dome of st. peter's will be in a similar state to that in which the colosaeum now is, and when its ruins may be preserved by the sanctifying influence of some new and unknown faith; when, perhaps, the statue of jupiter, which at present receives the kiss of the devotee, as the image of st. peter, may be employed for another holy use, as the personification of a future saint or divinity; and when the monuments of the papal magnificence shall be mixed with the same dust as that which now covers the tombs of the caesars. such, i am sorry to say, is the general history of all the works and institutions belonging to humanity. they rise, flourish, and then decay and fall; and the period of their decline is generally proportional to that of their elevation. in ancient thebes or memphis the peculiar genius of the people has left us monuments from which we can judge of their arts, though we cannot understand the nature of their superstitions. of babylon and of troy the remains are almost extinct; and what we know of these famous cities is almost entirely derived from literary records. ancient greece and rome we view in the few remains of their monuments; and the time will arrive when modern rome shall be what ancient rome now is; and ancient rome and athens will be what tyre or carthage now are, known only by coloured dust in the desert, or coloured sand, containing the fragments of bricks or glass, washed up by the wave of a stormy sea. i might pursue these thoughts still further, and show that the wood of the cross, or the bronze of the statue, decay as quickly as if they had not been sanctified; and i think i could show that their influence is owing to the imagination, which, when infinite time is considered, or the course of ages even, is null and its effect imperceptible; and similar results occur, whether the faith be that of osiris, of jupiter, of jehovah, or of jesus." to this ambrosio replied, his countenance and the tones of his voice expressing some emotion: "i do not think, onuphrio, that you consider this question with your usual sagacity or acuteness; indeed, i never hear you on the subject of religion without pain and without a feeling of regret that you have not applied your powerful understanding to a more minute and correct examination of the evidences of revealed religion. you would then, i think, have seen, in the origin, progress, elevation, decline and fall of the empires of antiquity, proofs that they were intended for a definite end in the scheme of human redemption; you would have found prophecies which have been amply verified; and the foundation or the ruin of a kingdom, which appears in civil history so great an event, in the history of man, in his religious institutions, as comparatively of small moment; you would have found the establishment of the worship of one god amongst a despised and contemned people as the most important circumstance in the history of the early world; you would have found the christian dispensation naturally arising out of the jewish, and the doctrines of the pagan nations all preparatory to the triumph and final establishment of a creed fitted for the most enlightened state of the human mind and equally adapted to every climate and every people." to this animated appeal of ambrosio, onuphrio replied in the most tranquil manner and with the air of an unmoved philosopher:--"you mistake me, ambrosio, if you consider me as hostile to christianity. i am not of the school of the french encyclopaedists, or of the english infidels. i consider religion as essential to man, and belonging to the human mind in the same manner as instincts belong to the brute creation, a light, if you please of revelation to guide him through the darkness of this life, and to keep alive his undying hope of immortality: but pardon me if i consider this instinct as equally useful in all its different forms, and still a divine light through whatever medium or cloud of human passion or prejudice it passes. i reverence it in the followers of brahmah, in the disciple of mahomet, and i wonder at in all the variety of forms it adopts in the christian world. you must not be angry with me that i do not allow infallibility to your church, having been myself brought up by protestant parents, who were rigidly attached to the doctrines of calvin." i saw ambrosio's countenance kindle at onuphrio's explanation of his opinions, and he appeared to be meditating an angry reply. i endeavoured to change the conversation to the state of the colosaeum, with which it had begun. "these ruins," i said, "as you have both observed, are highly impressive; yet when i saw them six years ago they had a stronger effect on my imagination; whether it was the charm of novelty, or that my mind was fresher, or that the circumstances under which i saw them were peculiar, i know not, but probably all these causes operated in affecting my mind. it was a still and beautiful evening in the end of may; the last sunbeams were dying away in the western sky and the first moonbeams shining in the eastern; the bright orange tints lighted up the ruins and as it were kindled the snows that still remained on the distant apennines, which were visible from the highest accessible part of the amphitheatre. in this glow of colouring, the green of advanced spring softened the grey and yellow tints of the decaying stones, and as the lights gradually became fainter, the masses appeared grander and more gigantic; and when the twilight had entirely disappeared, the contrast of light and shade in the beams of the full moon and beneath a sky of the brightest sapphire, but so highly illuminated that only jupiter and a few stars of the first magnitude were visible, gave a solemnity and magnificence to the scene which awakened the highest degree of that emotion which is so properly termed the sublime. the beauty and the permanency of the heavens and the principle of conservation belonging to the system of the universe, the works of the eternal and divine architect, were finely opposed to the perishing and degraded works of man in his most active and powerful state. and at this moment so humble appeared to me the condition of the most exalted beings belonging to the earth, so feeble their combinations, so minute the point of space, and so limited the period of time in which they act, that i could hardly avoid comparing the generations of man, and the effects of his genius and power, to the swarms of luceoli or fire-flies which were dancing around me and that appeared flitting and sparkling amidst the gloom and darkness of the ruins, but which were no longer visible when they rose above the horizon, their feeble light being lost and utterly obscured in the brightness of the moonbeams in the heavens." onuphrio said: "i am not sorry that you have changed the conversation. you have given us the history of a most interesting recollection and well expressed a solemn though humiliating feeling. in such moments and among such scenes it is impossible not to be struck with the nothingness of human glory and the transiency of human works. this, one of the greatest monuments on the face of the earth, was raised by a people, then its masters, only seventeen centuries ago; in a few ages more it will be but as dust, and of all the testimonials of the vanity or power of man, whether raised to immortalise his name, or to contain his decaying bones without a name, no one is known to have a duration beyond what is measured by the existence of a hundred generations; and it is only to multiply centuple for instance the period of time, and the memorials of a village and the monuments of a country churchyard may be compared with those of an empire and the remains of the world." ambrosio, to whom the conversation seemed disagreeable, put us in mind of an engagement we had made to spend the evening at the conversazione of a celebrated lady, and proposed to call the carriage. the reflections which the conversation and the scene had left in my mind little disposed me for general society. i requested them to keep their engagement, and said i was resolved to spend an hour amidst the solitude of the ruins, and desired them to send back the carriage for me. they left me, expressing a hope that my poetical or melancholy fancy might not be the occasion of a cold, and wished me the company of some of the spectres of the ancient romans. when i was left alone, i seated myself in the moonshine, on one of the steps leading to the seats supposed to have been occupied by the patricians in the colosaeum at the time of the public games. the train of ideas in which i had indulged before my friends left me continued to flow with a vividness and force increased by the stillness and solitude of the scene; and the full moon has always a peculiar effect on these moods of feeling in my mind, giving to them a wildness and a kind of indefinite sensation, such as i suppose belong at all times to the true poetical temperament. it must be so, i thought to myself; no new city will rise again out of the double ruins of this; no new empire will be founded upon these colossal remains of that of the old romans. the world, like the individual, flourishes in youth, rises to strength in manhood, falls into decay in age; and the ruins of an empire are like the decrepit frame of an individual, except that they have some tints of beauty which nature bestows upon them. the sun of civilisation arose in the east, advanced towards the west, and is now at its meridian; in a few centuries more it will probably be seen sinking below the horizon even in the new world, and there will be left darkness only where there is a bright light, deserts of sand where there were populous cities, and stagnant morasses where the green meadow or the bright cornfield once appeared. i called up images of this kind in my imagination. "time," i said, "which purifies, and as it were sanctifies the mind, destroys and brings into utter decay the body; and, even in nature, its influence seems always degrading. she is represented by the poets as eternal in her youth, but amongst these ruins she appears to me eternal in her age, and here no traces of renovation appear in the ancient of days." i had scarcely concluded this ideal sentence when my reverie became deeper, the ruins surrounding me appeared to vanish from my sight, the light of the moon became more intense, and the orb itself seemed to expand in a flood of splendour. at the same time that my visual organs appeared so singularly affected, the most melodious sounds filled my ear, softer yet at the same time deeper and fuller than i had ever heard in the most harmonious and perfect concert. it appeared to me that i had entered a new state of existence, and i was so perfectly lost in the new kind of sensation which i experienced that i had no recollections and no perceptions of identity. on a sudden the music ceased, but the brilliant light still continued to surround me, and i heard a low but extremely distinct and sweet voice, which appeared to issue from the centre of it. the sounds were at first musical like those of a harp, but they soon became articulate, as if a prelude to some piece of sublime poetical composition. "you, like all your brethren," said the voice, "are entirely ignorant of every thing belonging to yourselves, the world you inhabit, your future destinies, and the scheme of the universe; and yet you have the folly to believe you are acquainted with the past, the present, and the future. i am an intelligence somewhat superior to you, though there are millions of beings as much above me in power and in intellect as man is above the meanest and weakest reptile that crawls beneath his feet; yet something i can teach you: yield your mind wholly to the influence which i shall exert upon it, and you shall be undeceived in your views of the history of the world, and of the system you inhabit." at this moment the bright light disappeared, the sweet and harmonious voice, which was the only proof of the presence of a superior intelligence, ceased; i was in utter darkness and silence, and seemed to myself to be carried rapidly upon a stream of air, without any other sensation than that of moving quickly through space. whilst i was still in motion, a dim and hazy light, which seemed like that of twilight in a rainy morning, broke upon my sight, and gradually a country displayed itself to my view covered with forests and marshes. i saw wild animals grazing in large savannahs, and carnivorous beasts, such as lions and tigers, occasionally disturbing and destroying them; i saw naked savages feeding upon wild fruits, or devouring shell-fish, or fighting with clubs for the remains of a whale which had been thrown upon the shore. i observed that they had no habitations, that they concealed themselves in caves, or under the shelter of palm trees, and that the only delicious food which nature seemed to have given to them was the date and the cocoa- nut, and these were in very small quantities and the object of contention. i saw that some few of these wretched human beings that inhabited the wide waste before my eyes, had weapons pointed with flint or fish-bone, which they made use of for destroying birds, quadrupeds, or fishes, that they fed upon raw; but their greatest delicacy appeared to be a maggot or worm, which they sought for with great perseverance in the buds of the palm. when i had cast my eyes on the varied features of this melancholy scene, which was now lighted by a rising sun, i heard again the same voice which had astonished me in the colosaeum, and which said,--"see the birth of time! look at man in his newly created state, full of youth and vigour. do you see aught in this state to admire or envy?" as the last words fell on my ear, i was again, as before, rapidly put in motion, and i seemed again resistless to be hurried upon a stream of air, and again in perfect darkness. in a moment, an indistinct light again appeared before my eyes and a country opened upon my view which appeared partly wild and partly cultivated; there were fewer woods and morasses than in the scene which i had just before seen; i beheld men who were covered with the skins of animals, and who were driving cattle to enclosed pastures; i saw others who were reaping and collecting corn, others who were making it into bread; i saw cottages furnished with many of the conveniences of life, and a people in that state of agricultural and pastoral improvement which has been imagined by the poets as belonging to the golden age. the same voice, which i shall call that of the genius, said, "look at these groups of men who are escaped from the state of infancy: they owe their improvement to a few superior minds still amongst them. that aged man whom you see with a crowd around him taught them to build cottages; from that other they learnt to domesticate cattle; from others to collect and sow corn and seeds of fruit. and these arts will never be lost; another generation will see them more perfect; the houses, in a century more, will be larger and more convenient; the flocks of cattle more numerous; the corn-fields more extensive; the morasses will be drained, the number of fruit-trees increased. you shall be shown other visions of the passages of time, but as you are carried along the stream which flows from the period of creation to the present moment, i shall only arrest your transit to make you observe some circumstances which will demonstrate the truths i wish you to know, and which will explain to you the little it is permitted me to understand of the scheme of the universe." i again found myself in darkness and in motion, and i was again arrested by the opening of a new scene upon my eyes. i shall describe this scene and the others in the succession in which they appeared before me, and the observations by which they were accompanied in the voice of the wonderful being who appeared as my intellectual guide. in the scene which followed that of the agricultural or pastoral people, i saw a great extent of cultivated plains, large cities on the sea-shore, palaces--forums and temples ornamenting them; men associated in groups, mounted on horses, and performing military exercises; galleys moved by oars on the ocean; roads intersecting the country covered with travellers and containing carriages moved by men or horses. the genius now said, "you see the early state of civilisation of man; the cottages of the last race you beheld have become improved into stately dwellings, palaces, and temples, in which use is combined with ornament. the few men to whom, as i said before, the foundations of these improvements were owing, have had divine honours paid to their memory. but look at the instruments belonging to this generation, and you will find that they are only of brass. you see men who are talking to crowds around them, and others who are apparently amusing listening groups by a kind of song or recitation; these are the earliest bards and orators; but all their signs of thought are oral, for written language does not yet exist." the next scene which appeared was one of varied business and imagery. i saw a man, who bore in his hands the same instruments as our modern smiths, presenting a vase, which appeared to be made of iron, amidst the acclamations of an assembled multitude engaged in triumphal procession before the altars dignified by the name of apollo at delphi; and i saw in the same place men who carried rolls of papyrus in their hands and wrote upon them with reeds containing ink made from the soot of wood mixed with a solution of glue. "see," the genius said, "an immense change produced in the condition of society by the two arts of which you here see the origin; the one, that of rendering iron malleable, which is owing to a single individual, an obscure greek; the other, that of making thought permanent in written characters, an art which has gradually arisen from the hieroglyphics which you may observe on yonder pyramids. you will now see human life more replete with power and activity." again, another scene broke upon my vision. i saw the bronze instruments, which had belonged to the former state of society, thrown away; malleable iron converted into hard steel, this steel applied to a thousand purposes of civilised life; i saw bands of men who made use of it for defensive armour and for offensive weapons; i saw these iron- clad men, in small numbers subduing thousands of savages, and establishing amongst them their arts and institutions; i saw a few men on the eastern shores of europe, resisting, with the same materials, the united forces of asia; i saw a chosen band die in defence of their country, destroyed by an army a thousand times as numerous; and i saw this same army, in its turn, caused to disappear, and destroyed or driven from the shores of europe by the brethren of that band of martyred patriots; i saw bodies of these men traversing the sea, founding colonies, building cities, and wherever they established themselves, carrying with them their peculiar arts. towns and temples arose containing schools, and libraries filled with the rolls of the papyrus. the same steel, such a tremendous instrument of power in the hands of the warrior, i saw applied, by the genius of the artist, to strike forms even more perfect than those of life out of the rude marble; and i saw the walls of the palaces and temples covered with pictures, in which historical events were portrayed with the truth of nature and the poetry of mind. the voice now awakened my attention by saying, "you have now before you the vision of that state of society which is an object of admiration to the youth of modern times, and the recollections of which, and the precepts founded on these recollections, constitute an important part of your education. your maxims of war and policy, your taste in letters and the arts, are derived from models left by that people, or by their immediate imitators, whom you shall now see." i opened my eyes, and recognised the very spot in which i was sitting when the vision commenced. i was on the top of an arcade under a silken canopy, looking down upon the tens of thousands of people who were crowded in the seats of the colosaeum, ornamented with all the spoils that the wealth of a world can give; i saw in the arena below animals of the most extraordinary kind, and which have rarely been seen living in modern europe--the giraffe, the zebra, the rhinoceros, and the ostrich from the deserts of africa beyond the niger, the hippopotamus from the upper nile, and the royal tiger and the gnu from the banks of the ganges. looking over rome, which, in its majesty of palaces and temples, and in its colossal aqueducts bringing water even from the snows of the distant apennines, seemed more like the creation of a supernatural power than the work of human hands; looking over rome to the distant landscape, i saw the whole face, as it were, of the ancient world adorned with miniature images of this splendid metropolis. where the roman conquered, there he civilised; where he carried his arms, there he fixed likewise his household gods; and from the deserts of arabia to the mountains of caledonia there appeared but one people, having the same arts, language, and letters--all of grecian origin. i looked again, and saw an entire change in the brilliant aspect of this roman world--the people of conquerors and heroes was no longer visible; the cities were filled with an idle and luxurious population; those farms which had been cultivated by warriors, who left the plough to take the command of armies, were now in the hands of slaves; and the militia of freemen were supplanted by bands of mercenaries, who sold the empire to the highest bidder. i saw immense masses of warriors collecting in the north and east, carrying with them no other proofs of cultivation but their horses and steel arms; i saw these savages everywhere attacking this mighty empire, plundering cities, destroying the monuments of arts and literature, and, like wild beasts devouring a noble animal, tearing into pieces and destroying the roman power. ruin, desolation, and darkness were before me, and i closed my eyes to avoid the melancholy scene. "see," said the genius, "the melancholy termination of a power believed by its founders invincible, and intended to be eternal. but you will find, though the glory and greatness belonging to its military genius have passed away, yet those belonging to the arts and institutions, by which it adorned and dignified life, will again arise in another state of society." i opened my eyes again, and i saw italy recovering from her desolation--towns arising with governments almost upon the model of ancient athens and rome, and these different small states rivals in arts and arms; i saw the remains of libraries, which had been preserved in monasteries and churches by a holy influence which even the goth and vandal respected, again opened to the people; i saw rome rising from her ashes, the fragments of statues found amidst the ruins of her palaces and imperial villas becoming the models for the regeneration of art; i saw magnificent temples raised in this city become the metropolis of a new and christian world, and ornamented with the most brilliant masterpieces of the arts of design; i saw a tuscan city, as it were, contending with rome for pre-eminence in the productions of genius, and the spirit awakened in italy spreading its influence from the south to the north. "now," the genius said, "society has taken its modern and permanent aspect. consider for a moment its relations to letters and to arms as contrasted with those of the ancient world." i looked, and saw, that in the place of the rolls of papyrus, libraries were now filled with books. "behold," the genius said, "the printing-press; by the invention of faust the productions of genius are, as it were, made imperishable, capable of indefinite multiplication, and rendered an unalienable heritage of the human mind. by this art, apparently so humble, the progress of society is secured, and man is spared the humiliation of witnessing again scenes like those which followed the destruction of the roman empire. now look to the warriors of modern times; you see the spear, the javelin, the shield, and the cuirass are changed for the musket and the light artillery. the german monk who discovered gunpowder did not meanly affect the destinies of mankind; wars are become less bloody by becoming less personal; mere brutal strength is rendered of comparatively little avail; all the resources of civilisation are required to maintain and move a large army; wealth, ingenuity, and perseverance become the principal elements of success; civilised man is rendered in consequence infinitely superior to the savage, and gunpowder gives permanence to his triumph, and secures the cultivated nations from ever being again overrun by the inroads of millions of barbarians. there is so much identity of feature in the character of the two or three centuries that are just passed, that i wish you only to take a very transient view of the political and military events belonging to them. you will find attempts made by the chiefs of certain great nations to acquire predominance and empire; you will see those attempts, after being partially successful, resisted by other nations, and the balance of power, apparently for a moment broken, again restored. amongst the rival nations that may be considered as forming the republic of modern europe, you will see one pre-eminent for her maritime strength and colonial and commercial enterprise, and you will find she retains her superiority only because it is favourable to the liberty of mankind. but you must not yet suffer the vision of modern europe to pass from your eyes without viewing some other results of the efforts of men of genius, which, like those of gunpowder and the press, illustrate the times to which they belong, and form brilliant epochs in the history of the world. if you look back into the schools of regenerated italy, you will see in them the works of the greek masters of philosophy; and if you attend to the science taught in them, you will find it vague, obscure, and full of erroneous notions. you will find in this early period of improvement branches of philosophy even applied to purposes of delusion; the most sublime of the departments of human knowledge--astronomy--abused by impostors, who from the aspect of the planetary world pretended to predict the fortunes and destinies of individuals. you will see in the laboratories alchemists searching for a universal medicine, an elixir of life, and for the philosopher's stone, or a method of converting all metals into gold; but unexpected and useful discoveries you will find, even in this age, arise amidst the clouds of deception and the smoke of the furnace. delusion and error vanish and pass away, and truths seized upon by a few superior men become permanent, and the property of an enlightening world. amongst the personages who belong to this early period, there are two whom i must request you to notice--one an englishman, who pointed out the paths to the discovery of scientific truths, and the other a tuscan, who afforded the happiest experimental illustrations of the speculative views of his brother in science. you will see academies formed a century later in italy, france, and britain, in which the sciences are enlarged by new and varied experiments, and the true system of the universe developed by an illustrious englishman taught and explained. the practical results of the progress of physics, chemistry, and mechanics, are of the most marvellous kind, and to make them all distinct would require a comparison of ancient and modern states: ships that were moved by human labour in the ancient world are transported by the winds; and a piece of steel, touched by the magnet, points to the mariner his unerring course from the old to the new world; and by the exertions of one man of genius, aided by the resources of chemistry, a power, which by the old philosophers could hardly have been imagined, has been generated and applied to almost all the machinery of active life; the steam-engine performs not only the labour of horses, but of man, by combinations which appear almost possessed of intelligence; waggons are moved by it, constructions made, vessels caused to perform voyages in opposition to wind and tide, and a power placed in human hands which seems almost unlimited. to these novel and still extending improvements may be added others, whish, though of a secondary kind, yet materially affect the comforts of life, the collecting from fossil materials the elements of combustion, and applying them so as to illuminate, by a single operation, houses, streets, and even cities. if you look to the results of chemical arts you will find new substances of the most extraordinary nature applied to various novel purposes; you will find a few experiments in electricity leading to the marvellous result of disarming the thunder-cloud of its terrors, and you will see new instruments created by human ingenuity, possessing the same powers as the electrical organs of living animals. to whatever part of the vision of modern times you cast your eyes you will find marks of superiority and improvement, and i wish to impress upon you the conviction that the results of intellectual labour or of scientific genius are permanent and incapable of being lost. monarchs change their plans, governments their objects, a fleet or an army effect their purpose and then pass away; but a piece of steel toached by the magnet preserves its character for ever, and secures to man the dominion of the trackless ocean. a new period of society may send armies from the shores of the baltic to those of the euxine, and the empire of the followers of mahomet may be broken in pieces by a northern people, and the dominion of the britons in asia may share the fate of that of tamerlane or zengiskhan; but the steam-boat which ascends the delaware or the st. lawrence will be continued to be used, and will carry the civilisation of an improved people into the deserts of north america and into the wilds of canada. in the common history of the world, as compiled by authors in general, almost all the great changes of nations are confounded with changes in their dynasties, and events are usually referred either to sovereigns, chiefs, heroes, or their armies, which do, in fact, originate from entirely different causes, either of an intellectual or moral nature. governments depend far more than is generally supposed upon the opinion of the people and the spirit of the age and nation. it sometimes happens that a gigantic mind possesses supreme power and rises superior to the age in which he is born, such was alfred in england and peter in russia, but such instances are very rare; and, in general, it is neither amongst sovereigns nor the higher classes of society that the great improvers or benefactors of mankind are to be found. the works of the most illustrious names were little valued at the times when they were produced, and their authors either despised or neglected; and great, indeed, must have been the pure and abstract pleasure resulting from the exertion of intellectual superiority and the discovery of truth and the bestowing benefits and blessings upon society, which induced men to sacrifice all their common enjoyments and all their privileges as citizens to these exertions. anaxagoras, archimedes, roger bacon, galileo galilei, in their deaths or their imprisonments, offer instances of this kind, and nothing can be more striking than what appears to have been the ingratitude of men towards their greatest benefactors; but hereafter, when you understand more of the scheme of the universe, you will see the cause and the effect of this, and you will find the whole system governed by principles of immutable justice. i have said that in the progress of society all great and real improvements are perpetuated; the same corn which four thousand years ago was raised from an improved grass by an inventor worshipped for two thousand years in the ancient world under the name of ceres, still forms the principal food of mankind; and the potato, perhaps the greatest benefit that the old has derived from the new world, is spreading over europe, and will continue to nourish an extensive population when the name of the race by whom it was first cultivated in south america is forgotten. "i will now call your attention to some remarkable laws belonging to the history of society, and from the consideration of which you will be able gradually to develop the higher and more exalted principles of being. there appears nothing more accidental than the sex of an infant, yet take any great city or any province and you will find that the relations of males and females are unalterable. again, a part of the pure air of the atmosphere is continually consumed in combustion and respiration; living vegetables emit this principle during their growth; nothing appears more accidental than the proportion of vegetable to animal life on the surface of the earth, yet they are perfectly equivalent, and the balance of the sexes, like the constitution of the atmosphere, depends upon the principles of an unerring intelligence. you saw in the decline of the roman empire a people enfeebled by luxury, worn out by excess, overrun by rude warriors; you saw the giants of the north and east mixing with the pigmies of the south and west. an empire was destroyed, but the seeds of moral and physical improvement in the new race were sown; the new population resulting from the alliances of the men of the north with the women, of the south was more vigorous, more full of physical power, and more capable of intellectual exertion than their apparently ill-suited progenitors; and the moral effects or final causes of the migration of races, the plans of conquest and ambition which have led to revolutions and changes of kingdoms designed by man for such different objects have been the same in their ultimate results--that of improving by mixture the different families of men. an alaric or an attila, who marches with legions of barbarians for some gross view of plunder or ambition, is an instrument of divine power to effect a purpose of which he is wholly unconscious--he is carrying a strong race to improve a weak one, and giving energy to a debilitated population; and the deserts he makes in his passage will become in another age cultivated fields, and the solitude he produces will be succeeded by a powerful and healthy population. the results of these events in the moral and political world may be compared to those produced in the vegetable kingdom by the storms and heavy gales so usual at the vernal equinox, the time of the formation of the seed; the pollen or farina of one flower is thrown upon the pistil of another, and the crossing of varieties of plants so essential to the perfection of the vegetable world produced. in man moral causes and physical ones modify each other; the transmission of hereditary qualities to offspring is distinct in the animal world, and in the case of disposition to disease it is sufficiently obvious in the human being. but it is likewise a general principle that powers or habits acquired by cultivation are transmitted to the next generation and exalted or perpetuated; the history of particular races of men affords distinct proofs of this. the caucasian stock has always preserved its superiority, whilst the negro or flat-nosed race has always been marked for want of intellectual power and capacity for the arts of life. this last race, in fact, has never been cultivated, and a hundred generations, successively improved, would be required to bring it to the state in which the caucasian race was at the time of the formation of the greek republics. the principle of the improvement of the character of races by the transmission of hereditary qualities has not escaped the observations of the legislators of the ancient people. by the divine law of moses the israelites were enjoined to preserve the purity of their blood, and there was no higher crime than that of forming alliances with the idolatrous nations surrounding them. the brahmins of hindostan have established upon the same principle the law of caste, by which certain professions were made hereditary. in this warm climate, where labour is so oppressive, to secure perfection in any series of operations it seems essential to strengthen the powers by the forces acquired from this principle of hereditary descent. it will at first perhaps strike your mind that the mixing or blending of races is in direct opposition to this principle of perfection; but here i must require you to pause and consider the nature of the qualities belonging to the human being. excess of a particular power, which in itself is a perfection, becomes a defect; the organs of touch may be so refined as to show a diseased sensibility; the ear may become so exquisitely sensitive as to be more susceptible to the uneasiness produced by discords than to the pleasures of harmony. in the nations which have been long civilised the defects are generally those dependent on excess of sensibility--defects which are cured in the next generation by the strength and power belonging to a ruder tribe. in looking back upon the vision of ancient history, you will find that there never has been an instance of a migration to any extent of any race but the caucasian, and they have usually passed from the north to the south. the negro race has always been driven before these conquerors of the world; and the red men, the aborigines of america, are constantly diminishing in number, and it is probable that in a few centuries more their pure blood will be entirely extinct. in the population of the world, the great object is evidently to produce organised frames most capable of the happy and intellectual enjoyment of life--to raise man above the mere animal state. to perpetuate the advantages of civilisation, the races most capable of these advantages are preserved and extended, and no considerable improvement made by an individual is ever lost to society. you see living forms perpetuated in the series of ages, and apparently the quantity of life increased. in comparing the population of the globe as it now is with what it was centuries ago, you would find it considerably greater; and if the quantity of life is increased, the quantity of happiness, particularly that resulting from the exercise of intellectual power, is increased in a still higher ratio. now, you will say, 'is mind generated, is spiritual power created; or are those results dependent upon the organisation of matter, upon new perfections given to the machinery upon which thought and motion depend?' i proclaim to you," said the genius, raising his voice from its low and sweet tone to one of ineffable majesty, "neither of these opinions is true. listen, whilst i reveal to you the mysteries of spiritual natures, but i almost fear that with the mortal veil of your senses surrounding you, these mysteries can never be made perfectly intelligible to your mind. spiritual natures are eternal and indivisible, but their modes of being are as infinitely varied as the forms of matter. they have no relation to space, and, in their transitions, no dependence upon time, so that they can pass from one part of the universe to another by laws entirely independent of their motion. the quantity, or the number of spiritual essences, like the quantity or number of the atoms of the material world, are always the same; but their arrangements, like those of the materials which they are destined to guide or govern, are infinitely diversified; they are, in fact, parts more or less inferior of the infinite mind, and in the planetary systems, to one of which this globe you inhabit belongs, are in a state of probation, continually aiming at, and generally rising to a higher state of existence. were it permitted me to extend your vision to the fates of individual existences, i could show you the same spirit, which in the form of socrates developed the foundations of moral and social virtue, in the czar peter possessed of supreme power and enjoying exalted felicity in improving a rude people. i could show you the monad or spirit, which with the organs of newton displayed an intelligence almost above humanity, now in a higher and better state of planetary existence drinking intellectual light from a purer source and approaching nearer to the infinite and divine mind. but prepare your mind, and you shall at least catch a glimpse of those states which the highest intellectual beings that have belonged to the earth enjoy after death in their transition to now and more exalted natures." the voice ceased, and i appeared in a dark, deep, and cold cave, of which the walls of the colosaeum formed the boundary. from above a bright and rosy light broke into this cave, so that whilst below all was dark, above all was bright and illuminated with glory. i seemed possessed at this moment of a new sense, and felt that the light brought with it a genial warmth; odours like those of the most balmy flowers appeared to fill the air, and the sweetest sounds of music absorbed my sense of hearing; my limbs had a new lightness given to them, so that i seemed to rise from the earth, and gradually mounted into the bright luminous air, leaving behind me the dark and cold cavern, and the ruins with which it was strewed. language is inadequate to describe what i felt in rising continually upwards through this bright and luminous atmosphere. i had not, as is generally the case with persons in dreams of this kind, imagined to myself wings; but i rose gradually and securely as if i were myself a part of the ascending column of light. by degrees this luminous atmosphere, which was diffused over the whole of space, became more circumscribed, and extended only to a limited spot around me. i saw through it the bright blue sky, the moon and stars, and i passed by them as if it were in my power to touch them with my hand. i beheld jupiter and saturn as they appear through our best telescopes, but still more magnified, all the moons and belts of jupiter being perfectly distinct, and the double ring of saturn appearing in that state in which i have heard herschel often express a wish he could see it. it seemed as if i was on the verge of the solar system, and my moving sphere of light now appeared to pause. i again heard the low and sweet voice of the genius, which said, "you are now on the verge of your own system: will you go further, or return to the earth?" i replied, "i have left an abode which is damp, dreary, dark and cold; i am now in a place where all is life, light, and enjoyment; show me, at least before i return, the glimpse which you promised me of those superior intellectual natures and the modes of their being and their enjoyments." "there are creatures far superior," said the genius, "to any idea your imagination can form in that part of the system now before you, comprehending saturn, his moons and rings. i will carry you to the verge of the immense atmosphere of this planet. in that space you will see sufficient to wonder at, and far more than with your present organisation it would be possible for me to make you understand." i was again in motion, and again almost as suddenly at rest. i saw below me a surface infinitely diversified, something like that of an immense glacier covered with large columnar masses, which appeared as if formed of glass, and from which were suspended rounded forms of various sizes, which, if they had not been transparent, i might have supposed to be fruit. from what appeared to me to be analogous to masses of bright blue ice, streams of the richest tint of rose-colour or purple burst forth and flowed into basins, forming lakes or seas of the same colour. looking through the atmosphere towards the heavens, i saw brilliant opaque clouds of an azure colour that reflected the light of the sun, which had to my eyes an entirely new aspect, and appeared smaller, as if seen through a dense blue mist. i saw moving on the surface below me immense masses, the forms of which i find it impossible to describe; they had systems for locomotion similar to those of the morse or sea-horse, but i saw with great surprise that they moved from place to place by six extremely thin membranes, which they used as wings. their colours were varied and beautiful, but principally azure and rose-colour. i saw numerous convolutions of tubes, more analogous to the trunk of the elephant than to anything else i can imagine, occupying what i supposed to be the upper parts of the body, and my feeling of astonishment almost became one of disgust, from the peculiar character of the organs of these singular beings; and it was with a species of terror that i saw one of them mounting upwards, apparently flying towards those opaque clouds which i have before mentioned. "i know what your feelings are," said the genius; "you want analogies and all the elements of knowledge to comprehend the scene before you. you are in the same state in which a fly would be whose microscopic eye was changed for one similar to that of man; and you are wholly unable to associate what you now see with your former knowledge. but those beings who are before you, and who appear to you almost as imperfect in their functions as the zoophytes of the polar sea, to which they are not unlike in their apparent organisation to your eyes, have a sphere of sensibility and intellectual enjoyment far superior to that of the inhabitants of your earth. each of those tubes which appears like the trunk of an elephant is an organ of peculiar motion or sensation. they have many modes of perception of which you are wholly ignorant, at the same time that their sphere of vision is infinitely more extended than yours, and their organs of touch far more perfect and exquisite. it would be useless for me to attempt to explain their organisation, which you could never understand; but of their intellectual objects of pursuit i may perhaps give you some notion. they have used, modified, and applied the material world in a manner analogous to man; but with far superior powers they have gained superior results. their atmosphere being much denser than yours and the specific gravity of their planet less, they have been enabled to determine the laws belonging to the solar system with far more accuracy than you can possibly conceive, and any one of those beings could show you what is now the situation and appearance of your moon with a precision that would induce you to believe that he saw it, though his knowledge is merely the result of calculation. their sources of pleasure are of the highest intellectual nature; with the magnificent spectacle of their own rings and moons revolving round them, with the various combinations required to understand and predict the relations of these wonderful phenomena their minds are in unceasing activity and this activity is a perpetual source of enjoyment. your view of the solar system is bounded by uranus, and the laws of this planet form the ultimatum of your mathematical results; but these beings catch a sight of planets belonging to another system and even reason on the phenomena presented by another sun. those comets, of which your astronomical history is so imperfect, are to them perfectly familiar, and in their ephemerides their places are shown with as much accurateness as those of jupiter or venus in your almanacks; the parallax of the fixed stars nearest them is as well understood as that of their own sun, and they possess a magnificent history of the changes taking place in the heavens and which are governed by laws that it would be vain for me to attempt to give you an idea of. they are acquainted with the revolutions and uses of comets; they understand the system of those meteoric formations of stones which have so much astonished you on earth; and they have histories in which the gradual changes of nebulas in their progress towards systems have been registered, so that they can predict their future changes. and their astronomical records are not like yours which go back only twenty centuries to the time of hipparchus; they embrace a period a hundred times as long, and their civil history for the same time is as correct as their astronomical one. as i cannot describe to you the organs of these wonderful beings, so neither can i show to you their modes of life; but as their highest pleasures depend upon intellectual pursuits, so you may conclude that those modes of life bear the strictest analogy to that which on the earth you would call exalted virtue. i will tell you however that they have no wars, and that the objects of their ambition are entirely those of intellectual greatness, and that the only passion that they feel in which comparisons with each other can be instituted are those dependent upon a love of glory of the purest kind. if i were to show you the different parts of the surface of this planet, you would see marvellous results of the powers possessed by these highly intellectual beings and of the wonderful manner in which they have applied and modified matter. those columnar masses, which seem to you as if arising out of a mass of ice below, are results of art, and processes are going on in them connected with the formation and perfection of their food. the brilliant coloured fluids are the results of such operations as on the earth would be performed in your laboratories, or more properly in your refined culinary apparatus, for they are connected with their system of nourishment. those opaque azure clouds, to which you saw a few minutes ago one of those beings directing his course, are works of art and places in which they move through different regions of their atmosphere and command the temperature and the quantity of light most fitted for their philosophical researches, or most convenient for the purposes of life. on the verge of the visible horizon which we perceive around us, you may see in the east a very dark spot or shadow, in which the light of the sun seems entirely absorbed; this is the border of an immense mass of liquid analogous to your ocean, but unlike your sea it is inhabited by a race of intellectual beings inferior indeed to those belonging to the atmosphere of saturn, but yet possessed of an extensive range of sensations and endowed with extraordinary power and intelligence. i could transport you to the different planets and show you in each peculiar intellectual beings bearing analogies to each other, but yet all different in power and essence. in jupiter you would see creatures similar to those in saturn, but with different powers of locomotion; in mars and venus you would find races of created forms more analogous to those belonging to the earth; but in every part of the planetary system you would find one character peculiar to all intelligent natures, a sense of receiving impressions from light by various organs of vision, and towards this result you cannot but perceive that all the arrangements and motions of the planetary bodies, their satellites and atmospheres are subservient. the spiritual natures therefore that pass from system to system in progression towards power and knowledge preserve at least this one invariable character, and their intellectual life may be said to depend more or less upon the influence of light. as far as my knowledge extends, even in other parts of the universe the more perfect organised systems still possess this source of sensation and enjoyment; but with higher natures, finer and more ethereal kinds of matter are employed in organisation, substances that bear the same analogy to common matter that the refined or most subtle gases do to common solids and fluids. the universe is everywhere full of life, but the modes of this life are infinitely diversified, and yet every form of it must be enjoyed and known by every spiritual nature before the consummation of all things. you have seen the comet moving with its immense train of light through the sky; this likewise has a system supplied with living beings and their existence derives its enjoyment from the diversity of circumstances to which they are exposed; passing as it were through the infinity of space they are continually gratified by the sight of new systems and worlds, and you can imagine the unbounded nature of the circle of their knowledge. my power extends so far as to afford you a glimpse of the nature of a cometary world." i was again in rapid motion, again passing with the utmost velocity through the bright blue sky, and i saw jupiter and his satellites and saturn and his ring behind me, and before me the sun, no longer appearing as through a blue mist but in bright and unsupportable splendour, towards which i seemed moving with the utmost velocity; in a limited sphere of vision, in a kind of red hazy light similar to that which first broke in upon me in the colosaeum, i saw moving round me globes which appeared composed of different kinds of flame and of different colours. in some of these globes i recognised figures which put me in mind of the human countenance, but the resemblance was so awful and unnatural that i endeavoured to withdraw my view from them. "you are now," said the genius, "in a cometary system; those globes of light surrounding you are material forms, such as in one of your systems of religious faith have been attributed to seraphs; they live in that element which to you would be destruction; they communicate by powers which would convert your organised frame into ashes; they are now in the height of their enjoyment, being about to enter into the blaze of the solar atmosphere. these beings so grand, so glorious, with functions to you incomprehensible, once belonged to the earth; their spiritual natures have risen through different stages of planetary life, leaving their dust behind them, carrying with them only their intellectual power. you ask me if they have any knowledge or reminiscence of their transitions; tell me of your own recollections in the womb of your mother and i will answer you. it is the law of divine wisdom that no spirit carries with it into another state and being any habit or mental qualities except those which may be connected with its new wants or enjoyments; and knowledge relating to the earth would be no more useful to these glorified beings than their earthly system of organised dust, which would be instantly resolved into its ultimate atoms at such a temperature; even on the earth the butterfly does not transport with it into the air the organs or the appetites of the crawling worm from which it sprung. there is, however, one sentiment or passion which the monad or spiritual essence carries with it into all its stages of being, and which in these happy and elevated creatures is continually exalted; the love of knowledge or of intellectual power, which is, in fact, in its ultimate and most perfect development the love of infinite wisdom and unbounded power, or the love of god. even in the imperfect life that belongs to the earth this passion exists in a considerable degree, increases even with age, outlives the perfection of the corporeal faculties, and at the moment of death is felt by the conscious being, and its future destinies depend upon the manner in which it has been exercised and exalted. when it has been misapplied and assumed the forms of vague curiosity, restless ambition, vain glory, pride or oppression, the being is degraded, it sinks in the scale of existence and still belongs to the earth or an inferior system, till its errors are corrected by painful discipline. when, on the contrary, the love of intellectual power has been exercised on its noblest objects, in discovering and in contemplating the properties of created forms and in applying them to useful and benevolent purposes, in developing and admiring the laws of the eternal intelligence, the destinies of the sentient principle are of a nobler kind, it rises to a higher planetary world. from the height to which you have been lifted i could carry you downwards and show you intellectual natures even inferior to those belonging to the earth, in your own moon and in the lower planets, and i could demonstrate to you the effects of pain or moral evil in assisting in the great plan of the exaltation of spiritual natures; but i will not destroy the brightness of your present idea of the scheme of the universe by degrading pictures of the effects of bad passions and of the manner in which evil is corrected and destroyed. your vision must end with the glorious view of the inhabitants of the cometary worlds; i cannot show you the beings of the system to which i, myself, belong, that of the sun; your organs would perish before our brightness, and i am only permitted to be present to you as a sound or intellectual voice. _we_ are likewise in progression, but we see and know something of the plans of infinite wisdom; we feel the personal presence of that supreme deity which you only imagine; to you belongs faith, to us knowledge; and our greatest delight results from the conviction that we are lights kindled by his light and that we belong to his substance. to obey, to love, to wonder and adore, form our relations to the infinite intelligence. we feel his laws are those of eternal justice and that they govern all things from the most glorious intellectual natures belonging to the sun and fixed stars to the meanest spark of life animating an atom crawling in the dust of your earth. we know all things begin from and end in his everlasting essence, the cause of causes, the power of powers." the low and sweet voice ceased; it appeared as if i had fallen suddenly upon the earth, but there was a bright light before me and i heard my name loudly called; the voice was not of my intellectual guide--the genius before me was my servant bearing a flambeau in his hand. he told me he had been searching me in vain amongst the ruins, that the carriage had been waiting for me above an hour, and that he had left a large party of my friends assembled in the palazzo f---. dialogue the second. discussions connected with the vision in the colosaeum. the same friends, ambrosio and onuphrio, who were my companions at rome in the winter, accompanied me in the spring to naples. many conversations occurred in the course of our journey which were often to me peculiarly instructive, and from the difference of their opinions generally animated and often entertaining. i shall detail one of these conversations, which took place in the evening on the summit of vesuvius, and the remembrance of which from its connection with my vision in the colosaeum has always a peculiar interest for me. we had reached with some labour the edge of the crater and were admiring the wonderful scene around us. i shall give the conversation in the words of the persons of the drama. _philalethes_.--it is difficult to say whether there is more of sublimity or beauty in the scene around us. nature appears at once smiling and frowning, in activity and repose. how tremendous is the volcano, how magnificent this great laboratory of nature in its unceasing fire, its subterraneous lightnings and thunder, its volumes of smoke, its showers of stones and its rivers of ignited lava! how contrasted the darkness of the scoriae, the ruins and the desolation round the crater with the scene below! there we see the rich field covered with flax, or maize, or millet, and intersected by rows of trees which support the green and graceful festoons of the vine; the orange and lemon tree covered with golden fruit appear in the sheltered glens; the olive trees cover the lower hills; islands purple in the beams of the setting sun are scattered over the sea in the west, and the sky is tinted with red softening into the brightest and purest azure; the distant mountains still retain a part of the snows of winter, but they are rapidly melting and they absolutely seem to melt reflecting the beams of the setting sun, glowing as if on fire. and man appears emulous of nature, for the city below is full of activity; the nearest part of the bay is covered with boats, busy multitudes crowd the strand, and at the same time may be seen a number of the arts belonging to civilised society in operation--house-building, ship-building, rope-making, the manipulations of the smith and of the agriculturist, and not only the useful arts, but even the amusements and luxuries of a great metropolis may be witnessed from the spot in which we stand; that motley crowd is collected round a policinello, and those smaller groups that surround the stalls are employed in enjoying the favourite food and drink of the lazzaroni. _ambrosio_.--we see not only the power and activity of man, as existing at present, and of which the highest example may be represented by the steam-boat which is now departing for palermo, but we may likewise view scenes which carry us into the very bosom of antiquity, and, as it were, make us live with the generations of past ages. those small square buildings, scarcely visible in the distance, are the tombs of distinguished men amongst the early greek colonists of the country; and those rows of houses, without roofs, which appear as if newly erecting, constitute a roman town restored from its ashes, that remained for centuries as if it had been swept from the face of the earth. when you study it in detail you will hardly avoid the illusion that it is a rising city; you will almost be tempted to ask where are the workmen, so perfect art the walls of the houses, so bright and uninjured the painting upon them. hardly anything is wanting to make this scene a magnificent epitome of all that is most worthy of admiration in nature and art; had there been in addition to the other objects a fine river and a waterfall the epitome would, i think, have been absolutely perfect. _phil_.--you are most unreasonable in imagining additions to a scene which it is impossible to embrace in one view, and which presents so many objects to the senses, the memory, and to the imagination; yet there is a river in the valley between naples and castel del mare; you may see its silver thread and the white foam of its torrents in the distance, and if you were geologists you would find a number of sources of interest, which have not been mentioned, in the scenery surrounding us. somma which is before us, for instance, affords a wonderful example of a mountain formed of marine deposits, and which has been raised by subterraneous fire, and those large and singular veins which you see at the base and rising through the substance of the strata are composed of volcanic porphyry, and offer a most striking and beautiful example of the generation and structure of rocks and mineral formations. _onuphrio_.--as we passed through portici, on the road to the base of vesuvius, it appeared to me that i saw a stone which had an ancient roman inscription upon it, and which occupied the place of a portal in the modern palace of the barberini. _phil_.--this is not an uncommon circumstance: most of the stones used in the palaces of portici had been employed more than two thousand years before in structures raised by the ancient romans or greek colonists; and it is not a little remarkable that the buildings of herculaneum, a town covered with ashes, tufa, and lava, from the first recorded eruption of vesuvius more than seventeen hundred years ago, should have been constructed of volcanic materials produced by some antecedent igneous action of the mountain in times beyond the reach of history; and it is still more remarkable that men should have gone on for so many ages making erections in spots where their works have been so often destroyed, inattentive to the voice of time or the warnings of nature. _onu_.--this last fact recalls to my recollection an idea which philalethes started in the remarkable dream which he would have us believe occurred to him in the colosaeum, namely--that no important facts which can be useful to society are ever lost; and that, like these stones, which though covered with ashes or hidden amongst ruins, they are sure to be brought forward again and made use of in some new form. _amb_.--i do not see the justness of the analogy to which onuphrio refers; but there are many parts of that vision on which i should wish to hear the explanations of philalethes. i consider it in fact as a sort of poetical epitome of his philosophical opinions, and i regard this vision or dream as a mere web of his imagination in which he intended to catch us, his summer-flies and travelling companions. _phil_.--there, ambrosio, you do me wrong. i will acknowledge, if you please, that the vision in the colosaeum is a fiction; but the most important parts of it really occurred to me in sleep, particularly that in which i seemed to leave the earth and launch into the infinity of space under the guidance of a tutelary genius. and the origin and progress of civil society form likewise parts of another dream which i had many years ago, and it was in the reverie which happened when you quitted me in the colosaeum that i wove all these thoughts together, and gave them the form in which i narrated them to you. _amb_.--of course we may consider them as an accurate representation of your waking thoughts. _phil_.--i do not say that they strictly are so, for i am not quite convinced that dreams are always representations of the state of the mind modified by organic diseases or by associations. there are certainly no absolutely new ideas produced in sleep, yet i have had more than one instance, in the course of my life, of most extraordinary combinations occurring in this state, which have had considerable influence on my feelings, my imagination, and my health. _onu_.--why philalethes, you are becoming a visionary, a dreamer of dreams. we shall perhaps set you down by the side of jacob behmen or of emanuel swedenbourg, and in an earlier age you might have been a prophet, and have ranked perhaps with mahomet. but pray give us one of these instances in which such a marvellous influence was produced on your imagination and your health by a dream that we may form some judgment of the nature of your second sight or inspirations; and whether they have any foundation, or whether they are not, as i believe, really unfounded, inventions of the fancy, dreams respecting dreams. _phil_.--i anticipate unbelief, and i expose myself to your ridicule in the statement i am about to make, yet i shall mention nothing but a simple fact. almost a quarter of a century ago, as you know, i contracted that terrible form of typhus-fever known by the name of gaol- fever, i may say, not from any imprudence of my own, but whilst engaged in putting in execution a plan for ventilating one of the great prisons of the metropolis. my illness was severe and dangerous. as long as the fever continued, my dreams or delirium were most painful and oppressive; but when the weakness consequent to exhaustion came on, and when the probability of death seemed to my physicians greater than that of life, there was an entire change in all my ideal combinations. i remained in an apparently senseless or lethargic state, but in fact my mind was peculiarly active; there was always before me the form of a beautiful woman, with whom i was engaged in the most interesting and intellectual conversation. _amb_.--the figure of a lady with whom you were in love. _phil_.--no such thing; i was passionately in love at the time, but the object of my admiration was a lady with black hair, dark eyes, and pale complexion; this spirit of my vision, on the contrary, had brown hair, blue eyes, and a bright rosy complexion, and was, as far as i can recollect, unlike any of the amatory forms which in early youth had so often haunted my imagination. her figure for many days was so distinct in my mind, as to form almost a visual image. as i gained strength, the visits of my good angel (for so i called it) became less frequent, and when i was restored to health they were altogether discontinued. _onu_.--i see nothing very strange in this--a mere reaction of the mind after severe pain--and, to a young man of twenty-five, there are few more pleasurable images than that of a beautiful maiden with blue eyes, blooming cheeks, and long nut-brown hair. _phil_.--but all my feelings and all my conversations with this visionary maiden were of an intellectual and refined nature. _onu_.--yes, i suppose, as long as you were ill. _phil_.--i will not allow you to treat me with ridicule on this point till you have heard the second part of my tale. ten years after i had recovered from the fever, and when i had almost lost the recollection of the vision, it was recalled to my memory by a very blooming and graceful maiden, fourteen or fifteen years old, that i accidentally met during my travels in illyria; but i cannot say that the impression made upon my mind by this female was very strong. now comes the extraordinary part of the narrative. ten years after, twenty years after my first illness, at a time when i was exceedingly weak from a severe and dangerous malady, which for many weeks threatened my life, and when my mind was almost in a desponding state, being in a course of travels ordered by my medical advisers, i again met the person who was the representative of my visionary female, and to her kindness and care i believe i owe what remains to me of existence. my despondency gradually disappeared, and though my health still continued weak, life began to possess charms for me which i had thought were for ever gone; and i could not help identifying the living angel with the vision which appeared as my guardian genius during the illness of my youth. _onu_.--i really see nothing at all in this fact, whether the first or the second part of the narrative be considered, beyond the influence of an imagination excited by disease. from youth, even to age, women are our guardian angels, our comforters; and i dare say any other handsome young female, who had been your nurse in your last illness, would have coincided with your remembrance of the vision, even though her eyes had been hazel and her hair flaxen. nothing can be more loose than the images represented in dreams following a fever, and with the nervous susceptibility produced by your last illness, almost any agreeable form would have become the representative of your imaginary guardian genius. thus it is, that by the power of fancy, material forms are clothed in supernatural attributes; and in the same manner imaginary divinities have all the forms of mortality bestowed upon them. the gods of the pagan mythology were in all their characters and attributes exalted human beings; the demon of the coward, and the angelic form that appears in the dream of some maid smitten by devotion, and who, having lost her earthly lover, fixes her thoughts on heaven, are clothed in the character and vestments of humanity changed by the dreaminess of passion. _amb_.--with such a tendency, philalethes, as you have shown to believe in something like a supernatural or divine influence on the human mind, i am astonished there should be so much scepticism belonging to your vision in the colosaeum. and your view of the early state of man, after his first creation, is not only incompatible with revelation, but likewise with reason and everything that we know respecting the history or traditions of the early nations of antiquity. _phil_.--be more distinct and detailed in your statements, ambrosio, that i may be able to reply to them; and whilst we are waiting for the sunrise we may discuss the subject, and for this, let us seat ourselves on these stones, where we shall be warmed by the vicinity of the current of lava. _amb_.--you consider man, in his early or first created state, a savage, like those who now inhabit new holland or new zealand, acquiring by the little use that they make of a feeble reason the power of supporting and extending life. now, i contend, that if man had been so created, he must inevitably have been destroyed by the elements or devoured by savage beasts, so infinitely his superiors in physical force. he must, therefore, have been formed with various instinctive faculties and propensities, with a perfection of form and use of organs fitting him to become the master of the earth; and, it appears to me, that the account given in genesis of the first parents of mankind having been placed in a garden fitted with everything necessary to their existence and enjoyment, and ordered to increase and multiply there, is strictly in harmony with reason, and accordant with all just metaphysical views of the human mind. man as he now exists can only be raised with great care and difficulty from the infant to the mature state; all his motions are at first automatic, and become voluntary by association; he has to learn everything by slow and difficult processes, many months elapse before he is able to stand, and many years before he is able to provide for the common wants of life. without the mother or the nurse in his infant state, he would die in a few hours; and without the laborious discipline of instruction and example, he would remain idiotic and inferior to most other animals. his reason is only acquired gradually, and when in its highest perfection is often uncertain in its results. he must, therefore, have been created with instincts that for a long while supplied the want of reason, and which enabled him from the first moment of his existence to provide for his wants, to gratify his desires, and enjoy the power and the activity of life. _phil_.--i acknowledge that your objection has some weight, but not so much as you would attribute to it. i will suppose that the first created man or men had certain powers or instincts, such as now belong to the rudest savages of the southern hemisphere; i will suppose them created with the use of their organs for defence and offence and with passions and propensities enabling them to supply their own wants. and i oppose the fact of races who are now actually in this state to your vague historical or traditionary records; and their gradual progress or improvement from this early state of society to that of the highest state of civilisation or refinement may, i think, be easily deduced from the exertions of reason assisted by the influence of the moral powers and of physical circumstances. accident, i conceive, must have had some influence in laying the foundations of certain arts; and a climate in which labour was not too oppressive, and in which the exertion of industry was required to provide for the wants of life must have fixed the character of the activity of the early improving people; where nature is too kind a mother, man is generally a spoiled child; where she is severe, and a stepmother, his powers are usually withered and destroyed. the people of the south and the north and those between the tropics offer, even at this day, proof of the truth of this principle; and it is even possible now to find on the surface of the earth, all the different gradations of the states of society, from that in which man is scarcely removed above the brute, to that in which he appears approaching in his nature to a divine intelligence. besides, reason being the noblest gift of god to man, i can hardly suppose that an infinitely powerful and all- wise creator would bestow upon the early inhabitants of the globe a greater proportion of instinct than was at first necessary to preserve their existence, and that he would not leave the great progress of their improvement to the development and exaltation of their reasoning powers. _amb_.--you appear to me in your argument to have forgotten the influence that any civilised race must possess over savages; and many of the nations which you consider as in their original state, may have descended from nations formerly civilised; and, it is quite as easy to trace the retrograde steps of a people as their advances; the savage hordes who now inhabit the northern coast of africa are probably descended from the opulent, commercial, and ingenious carthaginians who once contended with rome for the empire of the world; and even nearer home, we might find in southern italy and her islands, proofs of a degradation not much inferior. what i contend for is the civilisation of the first patriarchal races who peopled the east, and who passed into europe from armenia, in which paradise is supposed to have been placed. the early civilisation of this race could only have been in consequence of their powers and instincts having been of a higher character than those of savages. they appear to have been small families--a state not at all fitted for the discovery of arts by the exercise of the mind; and they professed the most sublime form of religion, the worship of one supreme intelligence--a truth which, after a thousand years of civilisation, was with difficulty attained by the most powerful efforts of reasoning by the greek sages. it appears to me, that in the history of the jews, nothing can be more in conformity to our ideas of just analogy than this series of events. our first parents were created with everything necessary for their wants and their happiness; they had only one duty to perform, by their obedience to prove their love and devotion to their creator. in this they failed, and death--or the fear of death--became a curse upon their race; but the father of mankind repented, and his instinctive or intellectual powers given by revelation were transmitted to his offspring more or less modified by their reason, which they had gained as the fruit of their disobedience. one branch of his offspring, however, in whom faith shone forth above reason, retained their peculiar powers and institutions and preserved the worship of jehovah pure, whilst many of the races sprung from their brethren became idolatrous, and the clear light of heaven was lost through the mist of the senses; and that being, worshipped by the israelites only as a mysterious word, was forgotten by many of the nations who lived in the neighbouring countries, and men, beasts, the parts of the visible universe, and even stocks and stones, were set up as objects of adoration. the difficulty which the divine legislators of the jewish people had to preserve the purity of their religion amongst the idolatrous nations by whom they were surrounded, proves the natural evil tendency of the human mind after the fall of man. and, whoever will consider the nature of the mosaical or ceremonial law and the manner in which it was suspended before the end of the roman empire, the expiatory sacrifice of the messiah, the fear of death destroyed by the blessed hopes of immortality established by the resurrection of jesus christ, the destruction of jerusalem by titus, and the triumphs of christianity over paganism in the time of constantine, can i think, hardly fail to acknowledge the reasonableness of the truth of revealed religion as founded upon the early history of man; and whoever acknowledges this reasonableness and this truth, must i think be dissatisfied with the view which philalethes or his genius has given of the progress of society, and will find in it one instance, amongst many others that might be discovered, of the vague and erring results of his so much boasted human reason. _onu_.--i fear i shall shock ambrosio, but i cannot help vindicating a little the philosophical results of human reason, which it must be allowed are entirely hostile to his ideas. i agree with philalethes that it is the noblest gift of god to man; and i cannot think that ambrosio's view of the paradisaical condition and the fall of man and the progress of society is at all in conformity with the ideas we ought to form of the institutions of an infinitely wise and powerful being. besides, ambrosio speaks of the reasonableness of his own opinions; of course his notions of reason must be different from mine, or we have adopted different forms of logic. i do not find in the biblical history any idea of the supreme intelligence conformable to those of the greek philosophers; on the contrary, i find jehovah everywhere described as a powerful material being, endowed with organs, feelings, and passions similar to those of a great and exalted human agent. he is described as making man in his own image, as walking in the garden in the cool of the evening, as being pleased with sacrificial offerings, as angry with adam and eve, as personally cursing cain for his crime of fratricide, and even as providing our first parents with garments to hide their nakedness; then he appears a material form in the midst of flames, thunder and lightning, and was regarded by the levites as having a fixed residence in the ark. he is contrasted throughout the whole of the old testament with the gods of the heathens, only as being more powerful; and in the strange scene which took place in pharaoh's court he seemed to have measured his abilities with those of certain seers or magicians, and to have proved his superiority only by producing greater and more tremendous plagues. in all the early history of the jewish nation there is no conception approaching to the sublimity of that of anaxagoras, who called god the intelligence or [greek text]. he appears always, on the contrary, like the genii of arabian romance, living in clouds, descending on mountains, urging his chosen people to commit the most atrocious crimes, to destroy all the races not professing the same worship, and to exterminate even the child and the unborn infant. then, i find in the old testament no promise of a spiritual messiah, but only of a temporal king, who, as the jews believe, is yet to come. the serpent in genesis has no connection with the spirit of evil, but is described only as the most subtle beast of the field, and, having injured man, there was to be a perpetual enmity between their races--the serpent when able was to bite the heel of the man, and the man when an opportunity occurred was to bruise the head of the serpent. i will allow, if you please, that an instinct of religion or superstition belongs to the human mind, and that the different forms which this instinct assumes depend upon various circumstances and accidents of history and climate; but i am not sure that the religion of the jews was superior to that of the sabaeans who worshipped the stars, or the ancient persians who adored the sun as the visible symbol of divine power, or the eastern nations who in the various forms of the visible universe worshipped the powers and energies of the divinity. i feel like the ancient romans with respect to toleration; i would give a place to all the gods in my pantheon, but i would not allow the followers of brahmah or of christ to quarrel about the modes of incarnation or the superiority of the attributes of their trien god. _amb_.--you have mistaken me, onuphrio, if you think i am shocked by your opinions; i have seen too much of the wanderings of human reason ever to be surprised by them, and the views you have adopted are not uncommon amongst young men of very superior talents, who have only slightly examined the evidences of revealed religion. but i am glad to find that you have not adopted the code of infidelity of many of the french revolutionists and of an english school of sceptics, who find in the ancient astronomy all the germs of the worship of the hebrews, who identify the labours of hercules with those of the jewish heroes, and who find the life, death and resurrection of the messiah in the history of the solar day. you, at least, allow the existence of a peculiar religious instinct, or, as you are pleased to call it, superstition, belonging to the human mind, and i have hopes that upon this foundation you will ultimately build up a system of faith not unworthy a philosopher and a christian. man, with whatever religious instincts he was created, was intended to communicate with the visible universe by sensations and act upon it by his organs, and in the earliest state of society he was more particularly influenced by his gross senses. allowing the existence of a supreme intelligence and his beneficent intentions towards man, the ideas of his presence which he might think fit to impress upon the mind, either for the purpose of veneration, or of love, of hope or fear, must have been in harmony with the general train of his sensations--i am not sure that i make myself intelligible. the same infinite power which in an instant could create a universe, could of course so modify the ideas of an intellectual being as to give them that form and character most fitted for his existence; and i suppose in the early state of created man he imagined that he enjoyed the actual presence of the divinity and heard his voice. i take this to be the first and simplest result of religious instinct. in early times amongst the patriarchs i suppose these ideas were so vivid as to be confounded with impressions; but as religious instinct probably became feebler in their posterity, the vividness of the impressions diminished, and they then became visions or dreams, which with the prophets seem to have constituted inspiration. i do not suppose that the supreme being ever made himself known to man by a real change in the order of nature, but that the sensations of men were so modified by their instincts as to induce the belief in his presence. that there was a divine intelligence continually acting upon the race of seth as his chosen people, is, i think, clearly proved by the events of their history, and also that the early opinions of a small tribe in judaea were designed for the foundation of the religion of the most active and civilised and powerful nations of the world, and that after a lapse of three thousand years. the manner in which christianity spread over the world with a few obscure mechanics or fishermen for its promulgators; the mode in which it triumphed over paganism even when professed and supported by the power and philosophy of a julian; the martyrs who subscribed to the truth of christianity by shedding their blood for the faith; the exalted nature of those intellectual men by whom it has been professed who had examined all the depths of nature and exercised the profoundest faculties of thought, such as newton, locke, and hartley, all appear to me strong arguments in favour of revealed religion. i prefer rather founding my creed upon the fitness of its doctrines than upon historical evidences or the nature of its miracles. the divine intelligence chooses that men should be convinced according to the ordinary train of their sensations, and on all occasions it appears to me more natural that a change should take place in the human mind than in the order of nature. the popular opinion of the people of judaea was that certain diseases were occasioned by devils taking possession of a human being; the disease was cured by our saviour, and this in the gospel is expressed by his casting out devils. but without entering into explanations respecting the historical miracles belonging to christianity, it is sufficient to say that its truth is attested by a constantly existing miracle, the present state of the jews, which was predicted by jesus; their temple and city were destroyed, and all attempts made to rebuild it have been vain, and they remain the despised and outcasts of the world. _onu_.--but you have not answered my objections with respect to the cruelties exercised by the jews under the command of jehovah, which appear to me in opposition to all our views of divine justice. _amb_.--i think even philalethes will allow that physical and moral diseases are hereditary, and that to destroy a pernicious unbelief or demoniacal worship it was necessary to destroy the whole race root and branch. as an example, i will imagine a certain contagions disease which is transmitted by parents to children, and which, like the plague, is communicated to sound persons by contact; to destroy a family of men who would spread this disease over the whole earth would unquestionably be a mercy. besides, i believe in the immortality of the sentient principle in man; destruction of life is only a change of existence, and supposing the new existence a superior one it is a gain. to the supreme intelligence the death of a million of human beings is the mere circumstance of so many spiritual essences changing their habitations, and is analogous to the myriad millions of larvae that leave their coats and shells behind them and rise into the atmosphere, as flies in a summer day. when man measures the works of the divine mind by his own feeble combinations, he must wander in gross error; the infinite can never be understood by the finite. _onu_.--as far as i can comprehend your reasoning, the priests of juggernaut might make the same defence for their idol, and find in such views a fair apology for the destruction of thousands of voluntary victims crushed to pieces by the feet of the sacred elephant. _amb_.--undoubtedly they might, and i should allow the justness of their defence if i saw in their religion any germs of a divine institution fitted to become, like the religion of jehovah, the faith of the whole civilised world, embracing the most perfect form of theism and the most refined and exalted morality. i consider the early acts of the jewish nation as the lowest and rudest steps of a temple raised by the supreme being to contain the altar of sacrifice to his glory. in the early periods of society rude and uncultivated men could only be acted upon by gross and temporal rewards and punishments; severe rites and heavy discipline were required to keep the mind in order, and the punishment of the idolatrous nation served as an example for the jews. when christianity took the place of judaism the ideas of the supreme being became more pure and abstracted, and the visible attributes of jehovah and his angels appear to have been less frequently presented to the mind; yet even for many ages it seemed as if the grossness of our material senses required some assistance from the eye in fixing or perpetuating the character of religious instinct, and the church to which i belong, and i may say the whole christian church in early times, allowed visible images, pictures, statues, and relics as the means of awakening the stronger devotional feelings. we have been accused of worshipping merely inanimate objects, but this is a very false notion of the nature of our faith; we regard them merely as vivid characters representing spiritual existences and we no more worship them than the protestant does his bible when he kisses it under a solemn religious adjuration. the past, the present, and the future being the same to the infinite and divine intelligence, and man being created in love for the purposes of happiness, the moral and religious discipline to which he was submitted was in strict conformity to his progressive faculties and to the primary laws of his nature. it is but a rude analogy, yet it is the only one i can find, that of comparing the supreme being to a wise and good father who, to secure the well-being of his offspring, is obliged to adopt a system of rewards and punishments in which the senses at first and afterwards the imagination and reason are concerned; he terrifies them by the example of others, awakens their love of glory by pointing out the distinction and the happiness gained by superior men by adopting a particular line of conduct; he uses at first the rod, and gradually substitutes for it the fear of immediate shame; and having awakened the fear of shame and the love of praise or honour with respect to temporary and immediate actions he extends them to the conduct of the whole of life, and makes what was a momentary feeling a permanent and immutable principle. and obedience in the child to the will of such a parent may be compared to faith in and obedience to the will of the supreme being; and a wayward and disobedient child who reasons upon and doubts the utility of the discipline of such a father is much in the same state in which the adult man is who doubts if there be good in the decrees of providence and who questions the harmony of the plan of the moral universe. _onu_.--allowing the perfection of your moral scheme of religion and its fitness for the nature of man, i find it impossible to believe the primary doctrines on which this scheme is founded. you make the divine mind, the creator of infinite worlds, enter into the form of a man born of a virgin, you make the eternal and immortal god the victim of shameful punishment and suffering death on the cross, recovering his life after three days, and carrying his maimed and lacerated body into the heaven of heavens. _amb_.--you, like all other sceptics, make your own interpretations of the scriptures and set up a standard for divine power in human reason. the infinite and eternal mind, as i said before, fits the doctrines of religion to the minds by which they are to be embraced. i see no improbability in the idea that an integrant part of his essence may have animated a human form; there can be no doubt that this belief has existed in the human mind, and the belief constitutes the vital part of the religion. we know nothing of the generation of the human being in the ordinary course of nature; how absurd then to attempt to reason upon the acts of the divine mind! nor is there more difficulty in imagining the event of a divine conception than of a divine creation. to god the infinite, little and great, as measured by human powers, are equal; a creature of this earth, however humble and insignificant, may have the same weight with millions of superior beings inhabiting higher systems. but i consider all the miraculous parts of our religion as effected by changes in the sensations or ideas of the human mind, and not by physical changes in the order of nature; a man who has to repair a piece of machinery, as a clock, must take it to pieces, and, in fact, re-make it, but to infinite wisdom and power a change in the intellectual state of the human being may be the result of a momentary will, and the mere act of faith may produce the change. how great the powers of imagination are, even in ordinary life, is shown by many striking facts, and nothing seems impossible to this imagination when acted upon by divine influence. to attempt to answer all the objections which may be derived from the want of conformity in the doctrines of christianity to the usual order of events would be an interminable labour. my first principle is, that religion has nothing to do with the common order of events; it is a pure and divine instinct intended to give results to man which he cannot obtain by the common use of his reason, and which at first view often appear contradictory to it, but which when examined by the most refined tests, and considered in the most extensive and profound relations, are, in fact, in conformity with the most exalted intellectual knowledge, so that, indeed, the results of pure reason ultimately become the same with those of faith--the tree of knowledge is grafted upon the tree of life, and that fruit which brought the fear of death into the world, budding on an immortal stock, becomes the fruit of the promise of immortality. _onu_.--you derive christianity from judaism; i cannot see their connection, and it appears to me that the religion of mahomet is more naturally a scion from the stock of moses. christ was a jew, and was circumcised; this rite was continued by mahomet, and is to this day adopted by his disciples, though rejected by the christians; and the doctrines of mahomet appear to me to have a higher claim to divine origin than those of jesus; his morality is as pure, his theism purer, and his system of rewards and punishments after death as much in conformity with our ideas of eternal justice. _amb_.--i will willingly make the decision of the general question dependent upon the decision of this particular one. no attempts have been made by the mahometans to find any predictions respecting their founder in the old testament, and they have never pretended even that he was the messiah; therefore, as far as prophecy is concerned, there is no ground for admitting the truth of the religion of mahomet. it has been the fashion with a particular sect of infidels to praise the morality of the mahometans, but i think unjustly; they are said to be honest in their dealings and charitable to those of their own persuasion; but they allow polygamy and a plurality of women, and are despisers and persecutors of the nations professing a different faith. and what a contrast does this morality present to that of the gospel which inculcates charity to all mankind, and orders benevolent actions to be performed even to enemies! and the purity and simplicity of the infant is held up by christ as the model of imitation for his followers. then, in the rewards and punishments of the future state of the mahometans, how gross are all the ideas, how unlike the promises of a divine and spiritual being; their paradise is a mere earthly garden of sensual pleasure, and their houris represent the ladies of their own harems rather than glorified angelic natures. how different is the christian heaven, how sublime in its idea, indefinite, yet well suited to a being of intellectual and progressive faculties; "eye hath not seen, nor ear heard, nor hath it entered into the heart of man to conceive the joys that he hath prepared for those who love him." _onu_.--i confess your answer to my last argument is a triumphant one; but i cannot allow a question of such extent and of such a variety of bearings to be decided by so slight an advantage as that which you have gained by this answer. i will now offer another difficulty to you. the law of the jews, you will allow, was established by god himself and delivered to moses from the seat of his glory amongst storms, thunder, and lightnings, on mount sinai; why should this law, if pure and divine, have been overturned by the same being who established it? and all the ceremonies of the hebrews have been abolished by the first christians. _amb_.--i deny that the divine law of moses was abolished by christ, who himself says, "i came to confirm the law, not to destroy it." and the ten commandments form the vital parts of the foundation of the creed of the true christian. it appears that the religion of christ was the same pure theism with that of the patriarchs; and the rites and ceremonies established by moses seem to have been only adjuncts to the spiritual religion intended to suit a particular climate and a particular state of the jewish nation, rather a dress or clothing of the religion than forming a constituent part of it, a system of discipline of life and manners rather than an essential part of doctrine. the rites of circumcision and ablution were necessary to the health and perhaps even to the existence of a people living on the hottest part of the shores of the mediterranean. and in the sacrifices made of the first fruits and of the chosen of the flock, we may see a design not merely connected with the religious faith of the people but even with their political economy. to offer their choicest and best property as a proof of their gratitude to the supreme being was a kind of test of devotedness and obedience to the theocracy; and these sacrifices by obliging them to raise more produce and provide more cattle than were essential to their ordinary support, preserved them from the danger of famine, as in case of a dearth it was easy for the priests under the divine permission to apply those offerings to the necessities of the people. all the pure parts of the faith which had descended from abraham to david were preserved by jesus christ; but the ceremonial religion was fitted only for a particular nation and a particular country; christianity, on the contrary, was to be the religion of the world and of a civilised and improving world. and it appears to me to be an additional proof of its divine nature and origin, that it is exactly in conformity to the principles of the improvement and perfection of the human mind. when given to a particular race fixed in a peculiar climate, its objects were sensible, its discipline was severe, and its rites and ceremonies numerous and imposing, fitted to act upon weak, ignorant, and consequently obstinate men. in its gradual development it threw off its local character and its particular forms, and adopted ceremonies more fitted for mankind in general; and in its ultimate views, it preserves only pure, spiritual, and i may say philosophical doctrines, the unity of the divine nature and a future state, embracing a system of rewards and punishments suited to an accountable and immortal being. _phil_.--i have been attentively listening to your discussion. the views which ambrosio has taken of christianity certainly throw a light over it perfectly new to me; and, i must say in candour, that i am disposed to adopt his notion of the early state of society rather than that of my genius. i have always been accustomed to consider religious feeling as instinctive; but ambrosio's arguments have given me something approaching to a definite faith for an obscure and indefinite notion. i am willing to allow that man was created, not a savage, as he is represented in my vision, but perfect in his faculties and with a variety of instinctive powers and knowledge; that he transmitted these powers and knowledge to his offspring; but that by an improper use of reason in disobedience to the divine will, the instinctive faculties of most of his descendants became deteriorated and at last lost, but that these faculties were preserved in the race of abraham and david, and the full power again bestowed upon or recovered by christ. i am ready to allow the importance of religion in cultivating and improving the world; and ambrosio's view appears to me capable of being referred to a general law of our nature; and revelation may be regarded not as a partial interference but as a constant principle belonging to the mind of man, and the belief in supernatural forms and agency, the results of prophecies and the miracles, as one only of the necessary consequences of it. man, as a reasoning animal, must always have doubted of his immortality and plan of conduct; in all the results of faith, there is immediate submission to a divine will, which we are sure is good. we may compare the destiny of man in this respect to that of a migratory bird; if a slow flying bird, as a landrail in the orkneys in autumn, had reason and could use it as to the probability of his finding his way over deserts, across seas, and of securing his food in passing to a warm climate , miles off, he would undoubtedly starve in europe; under the direction of his instinct he securely arrives there in good condition. i have allowed the force of your objections to that part of my vision relating to the origin of society, but i hope you will admit that the conclusion of it is not inconsistent with the ideas derived from revelation respecting the future state of the human being. _amb_.--revelation has not disclosed to us the nature of this state, but only fixed its certainty. we are sure from geological facts, as well as from sacred history, that man is a recent animal on the globe, and that this globe has undergone one considerable revolution, since the creation, by water; and we are taught that it is to undergo another, by fire, preparatory to a new and glorified state of existence of man; but this is all we are permitted to know, and as this state is to be entirely different from the present one of misery and probation, any knowledge respecting it would be useless and indeed almost impossible. _phil_.--my genius has placed the more exalted spiritual natures in cometary worlds, and this last fiery revolution may be produced by the appulse of a comet. _amb_.--human fancy may imagine a thousand manners in which it may be produced, but upon such notions it is absurd to dwell. i will not allow your genius the slightest approach to inspiration, and i can admit no verisimility in a reverie which is fixed on a foundation you now allow to be so weak. but see, the twilight is beginning to appear in the orient sky, and there are some dark clouds on the horizon opposite to the crater of vesuvius, the lower edges of which transmit a bright light, showing the sun is already risen in the country beneath them. i would say that they may serve as an image of the hopes of immortality derived from revelation; for we are sure from the light reflected in those clouds that the lands below us are in the brightest sunshine, but we are entirely ignorant of the surface and the scenery; so, by revelation, the light of an imperishable and glorious world is disclosed to us; but it is in eternity, and its objects cannot be seen by mortal eye or imaged by mortal imagination. _phil_.--i am not so well read in the scriptures as i hope i shall be at no very distant time; but i believe the pleasures of heaven are mentioned more distinctly than you allow in the sacred writings. i think i remember that the saints are said to be crowned with palms and amaranths, and that they are described as perpetually hymning and praising god. _amb_.--this is evidently only metaphorical; music is the sensual pleasure which approaches nearest to an intellectual one, and probably may represent the delight resulting from the perception of the harmony of things and of truth seen in god. the palm as an evergreen tree and the amaranth a perdurable flower are emblems of immortality. if i am allowed to give a metaphorical allusion to the future state of the blest, i should image it by the orange grove in that sheltered glen, on which the sun is now beginning to shine, and of which the trees are at the same time loaded with sweet golden fruit and balmy silver flowers. such objects may well portray a state in which hope and fruition become one eternal feeling. _onu_.--this glorious sunrise seems to have made you both poetical. though with the darkest and most gloomy mind of the party i cannot help feeling its influence, i cannot help believing with you that the night of death will be succeeded by a bright morning; but, as in the scene below us, the objects are nearly the same as they were last evening, with more of brightness and brilliancy, with a fairer prospect in the east and more mist in the west, so i cannot help believing that our new state of existence must bear an analogy to the present one, and that the order of events will not be entirely different. _amb_.--your view is not an unnatural one; but i am rejoiced to find some symptoms of a change in your opinions. _onu_.--i wish with all my heart they were stronger; i begin to feel my reason a weight and my scepticism a very heavy load. your discussions have made me a philo-christian, but i cannot understand nor embrace all the views you have developed, though i really wish to do so. _amb_.--your wish, if sincere, i doubt not will be gratified. fix your powerful mind upon the harmony of the moral world, as you have been long accustomed to do upon the order of the physical universe, and you will see the scheme of the eternal intelligence developing itself alike in both. think of the goodness and mercy of omnipotence, and aid your contemplation by devotional feelings and mental prayer and aspirations to the source of all knowledge, and wait with humility for the light which i doubt not will be so produced in your mind. _onu_.--you again perplex me; i cannot believe that the adorations or offerings of so feeble a creature can influence the decrees of omnipotence. _amb_.--you mistake me: as to their influencing or affecting the supreme mind it is out of the question, but they affect your own mind, they perpetuate a habit of gratitude and of obedience which may gradually end in perfect faith, they discipline the affections and keep the heart in a state of preparation to receive and preserve all good and pious feelings. whoever passes from utter darkness into bright sunshine finds that he cannot at first distinguish objects better in one than in the other, but in a feeble light he acquires gradually the power of bearing a brighter one, and gains at last the habit not only of supporting it, but of receiving delight as well as instruction from it. in the pious contemplations that i recommend to you there is the twilight or sober dawn of faith which will ultimately enable you to support the brightness of its meridian sun. _onu_.--i understand you, but your metaphor is more poetical than just; your discipline, however, i have no doubt, is better fitted to enable me to bear the light than to contemplate it through the smoked or coloured glasses of scepticism. _amb_.--yes, for they not only diminish its brightness but alter its nature. dialogue the third. the unknown. the same persons accompanied me in many journeys by land and water to different parts of the phlegraean fields, and we enjoyed in a most delightful season, the beginning of may, the beauties of the glorious country which encloses the bay of naples, so rich, so ornamented with the gifts of nature, so interesting from the monuments it contains and the recollections it awakens. one excursion, the last we made in southern italy, the most important both from the extraordinary personage with whom it made me acquainted and his influence upon my future life, merits a particular detail which i shall now deliver to paper. it was on the th of may, -- that we left naples at three in the morning for the purpose of visiting the remains of the temples of paestum, and having provided relays of horses we found ourselves at about half- past one o'clock descending the hill of eboli towards the plain which contains these stupendous monuments of antiquity. were my existence to be prolonged through ten centuries, i think i could never forget the pleasure i received on that delicious spot. we alighted from our carriage to take some refreshment, and we reposed upon the herbage under the shade of a magnificent pine contemplating the view around and below us. on the right were the green hills covered with trees stretching towards salerno; beyond them were the marble cliffs which form the southern extremity of the bay of sorento; immediately below our feet was a rich and cultivated country filled with vineyards and abounding in villas, in the gardens of which were seen the olive and the cypress tree connected as if to memorialise how near to each other are life and death, joy and sorrow; the distant mountains stretching beyond the plain of paestum were in the full luxuriance of vernal vegetation; and in the extreme distance, as if in the midst of a desert, we saw the white temples glittering in the sunshine. the blue tyrrhene sea filled up the outline of this scene, which, though so beautiful, was not calm; there was a heavy breeze which blew full from the southwest; it was literally a zephyr, and its freshness and strength in the middle of the day were peculiarly balmy and delightful; it seemed a breath stolen by the spring from the summer. i never saw a deeper, brighter azure than that of the waves which rolled towards the shore, and which was rendered more striking by the pure whiteness of their foam. the agitation of nature seemed to be one of breathing and awakening life; the noise made by the waving of the branches of the pine above our heads and by the rattling of its cones was overpowered by the music of a multitude of birds which sung everywhere in the trees that surrounded us, and the cooing of the turtle- doves was heard even more distinctly than the murmuring of the waves or the whistling of the winds, so that in the strife of nature the voice of love was predominant. with our hearts touched by this extraordinary scene we descended to the ruins, and having taken at a farmhouse a person who acted as guide or cicerone, we began to examine those wonderful remains which have outlived even the name of the people by whom they were raised, and which continue almost perfect whilst a roman and a saracen city since raised have been destroyed. we had been walking for half an hour round the temples in the sunshine when our guide represented to us the danger that there was of suffering from the effects of malaria, for which, as is well known, this place is notorious, and advised us to retire into the interior of the temple of neptune. we followed his advice, and my companions began to employ themselves in measuring the circumference of one of the doric columns, when they suddenly called my attention to a stranger who was sitting on a camp-stool behind it. the appearance of any person in this place at this time was sufficiently remarkable, but the man who was before us from his dress and appearance would have been remarkable anywhere. he was employed in writing in a memorandum book when we first saw him, but he immediately rose and saluted us by bending the head slightly though gracefully; and this enabled me to see distinctly his person and dress. he was rather above the middle stature, slender, but with well-turned limbs; his countenance was remarkably intelligent, his eye hazel but full and strong, his front was smooth and unwrinkled, and but for some grey hairs, which appeared silvering his brown and curly locks, he might have been supposed to have hardly reached the middle age; his nose was aquiline, the expression of the lower part of his countenance remarkably sweet, and when he spoke to our guide, which he did with uncommon fluency in the neapolitan dialect, i thought i had never heard a more agreeable voice, sonorous yet gentle and silver-sounded. his dress was very peculiar, almost like that of an ecclesiastic, but coarse and light; and there was a large soiled white hat on the ground beside him, on which was fastened a pilgrim's cockle shell, and there was suspended round his neck a long antique blue enamelled phial, like those found in the greek tombs, and it was attached to a rosary of coarse beads. he took up his hat, and appeared to be retiring to another part of the building, when i apologised for the interruption we had given to his studies, begged him to resume them, and assured him that our stay in the building would be only momentary, for i saw that there was a cloud over the sun, the brightness of which was the cause of our retiring. i spoke in italian; he replied in english, observing that he supposed the fear of contracting the malaria fever had induced us to seek the shelter of the shade: but it is too early in the season to have much reasonable fear of this insidious enemy; yet, he added, this bottle which you may have observed here at my breast, i carry about with me, as a supposed preventive of the effects of malaria, and as far as my experience, a very limited one, however, has gone, it is effectual. i ventured to ask him what the bottle might contain, as such a benefit ought to be made known to the world. he replied, "it is a mixture which slowly produces the substance called by chemists chlorine, which is well known to be generally destructive to contagious matters; and a friend of mine who has lived for many years in italy, and who has made a number of experiments with it, by exposing himself to the danger of fever in the worst seasons and in the worst places, believes that it is a secure preventive. i am not convinced of this; but it can do no harm; and in waiting for more evidence of its utility, i employ it without putting the least confidence in its power; nor do i expose myself to the same danger as my friend has done for the sake of an experiment." i said, "i believe several scientific persons--brocchi amongst others--have doubted the existence of any specific matter in the atmosphere producing intermittent fevers in marshy countries and hot climates; and have been more disposed to attribute the disease to physical causes, dependent upon the great differences of temperature between day and night and to the refrigerating effects of the dense fogs common in such situations in the evening and morning; and, on this hypothesis, they have recommended warm woollen clothing and fires at night as the best preventives against these destructive diseases, so fatal to the peasants who remain in the summer and autumn in the neighbourhood of the maremme of rome, tuscany, or naples." the stranger said, "i am acquainted with the opinions of the gentlemen, and they undoubtedly have weight; but that a specific matter of contagion has not been detected by chemical means in the atmosphere of marshes does not prove its non-existence. we know so little of those agents that affect the human constitution, that it is of no use to reason on this subject. there can be no doubt that the line of malaria above the pontine marshes is marked by a dense fog morning and evening, and most of the old roman towns were placed upon eminences out of the reach of this fog. i have myself experienced a peculiar effect upon the organs of smell in the neighbourhood of marshes in the evening after a very hot day; and the instances in which people have been seized with intermittents by a single exposure in a place infested by malaria in the season of fevers gives, i think, a strong support to something like a poisonous material existing in the atmosphere in such spots; but i merely offer doubts. i hope the progress of physiology and of chemistry will at no very distant time solve this important problem." ambrosio now came forward, and bowing to the stranger, said he took the liberty, as he saw from his familiarity with the cicerone that he was well acquainted with paestum, of asking him whether the masses of travertine, of which the cyclopean walls and the temples were formed, were really produced by aqueous deposition from the river silaro, as he had often heard reported. the stranger replied, "that they were certainly produced by deposition from water; and such deposits are made by the silaro. but i rather believe," he said, "that a lake in the immediate neighbourhood of the city furnished the quarry from which these stones were excavated; and, in half an hour, if you like, after you have finished your examinations of the temples with your guide, i will accompany you to the spot from which it is evident that large masses of the travertine, marmor tiburtinum, or calcareous tufa, have been raised." we thanked him for his attention, accepted his invitation, took the usual walk round the temples, and returned to our new acquaintance, who led the way through the gate of the city to the banks of a pool or lake a short distance off. we walked to the borders on a mass of calcareous tufa, and we saw that this substance had even encrusted the reeds on the shore. there was something peculiarly melancholy in the character of this water; all the herbs around it were grey, as if encrusted with marble; a few buffaloes were slaking their thirst in it, which ran wildly away on our approach, and appeared to retire into a rocky excavation or quarry at the end of the lake; there were a number of birds, which, on examination, i found were sea swallows, flitting on the surface and busily employed with the libella or dragon- fly in destroying the myriads of gnats which rose from the bottom and were beginning to be very troublesome by their bites to us. "there," said the stranger, "is what i believe to be the source of those large and durable stones which you see in the plain before you. this water rapidly deposits calcareous matter, and even if you throw a stick into it, a few hours is sufficient to give it a coating of this substance. whichever way you turn your eyes you see masses of this recently-produced marble, the consequence of the overflowing of the lake during the winter floods, and in that large excavation where you saw the buffaloes disappear you may observe that immense masses have been removed, as if by the hand of art and in remote times. the marble that remains in the quarry is of the same texture and character as that which you see in the ruins of paestum, and i think it is scarcely possible to doubt that the builders of those extraordinary structures derived a part of their materials from this spot." ambrosio gave his assent to this opinion of the stranger; and i took the liberty of asking him as to the quantity of calcareous matter contained in solution in the lake, saying that it appeared to me, for so rapid and considerable an effect of deposition, there must be an unusual quantity of solid matter dissolved by the water or some peculiar circumstance of solution. the stranger replied, "this water is like many, i may say most of the sources which rise at the foot of the apennines: it holds carbonic acid in solution which has dissolved a portion of the calcareous matter of the rock through which it has passed. this carbonic acid is dissipated in the atmosphere, and the marble, slowly thrown down, assumes a crystalline form and produces coherent stones. the lake before us is not particularly rich in the quantity of calcareous matter that it contains, for, as i have found by experience, a pint of it does not afford more than five or six grains; but the quantity of fluid and the length of time are sufficient to account for the immense quantities of tufa and rock which in the course of ages have accumulated in this situation." onuphrio's curiosity was excited by this statement of the stranger, and he said, "may i take the liberty of asking if you have any idea as to the cause of the large quantity of carbonic acid which you have been so good as to inform us exists in most of the waters in this country?" the stranger replied, "i certainly have formed an opinion on this subject, which i willingly state to you. it can, i think, be scarcely doubted that there is a source of volcanic fire at no great distance from the surface in the whole of southern italy; and, this fire acting upon the calcareous rocks of which the apennines are composed, must constantly detach from them carbonic acid, which rising to the sources of the springs, deposited from the waters of the atmosphere, must give them their impregnation and enable them to dissolve calcareous matter. i need not dwell upon etna, vesuvius, or the lipari islands to prove that volcanic fires are still in existence; and there can be no doubt that in earlier periods almost the whole of italy was ravaged by them; oven rome itself, the eternal city, rests upon the craters of extinct volcanoes; and i imagine that the traditional and fabulous record of the destruction made by the conflagration of phaeton in the chariot of the sun and his falling into the po had reference to a great and tremendous igneous volcanic eruption, which extended over italy and ceased only near the po at the foot of the alps. be this as it may, the sources of carbonic acid are numerous, not merely in the neapolitan, but likewise in the roman and tuscan states. the most magnificent waterfall in europe, that of the velino, near terni, is partly fed by a stream containing calcareous matter dissolved by carbonic acid, and it deposits marble, which crystallises even in the midst of its thundering descent and foam in the bed in which it falls. the anio or teverone, which almost approaches in beauty to the velino in the number and variety of its falls and cascatelle, is likewise a calcareous water; and there is still a more remarkable one which empties itself into this river below tivoli, and which you have probably seen in your excursions in the campagna of rome, called the lacus albula or the lake of the solfatara." ambrosio said, "we remember it well, we saw it this very spring; we were carried there to examine some ancient roman baths, and we were struck by the blue milkiness of the water, by the magnitude of the source, and by the disagreeable smell of sulphuretted hydrogen which everywhere surrounded the lake." the stranger said, "when you return to latium i advise you to pay another visit to a spot which is interesting from a number of causes, some of which i will take the liberty of mentioning to you. you have only seen one lake, that where the ancient romans erected their baths, but there is another a few yards above it, surrounded by very high rushes, and almost hidden by them from the sight. this lake sends down a considerable stream of tepid water to the larger lake, but this water is less strongly impregnated with carbonic acid; the largest lake is actually a saturated solution of this gas, which escapes from it in such quantities in some parts of its surface that it has the appearance of being actually in ebullition. i have found by experiment that the water taken from the most tranquil part of the lake, even after being agitated and exposed to the air, contained in solution more than its own volume of carbonic acid gas with a very small quantity of sulphuretted hydrogen, to the presence of which, i conclude, its ancient use in curing cutaneous disorders may be referred. its temperature, i ascertained, was in the winter in the warmest parts above degrees of fahrenheit, and it appears to be pretty constant, for i have found it differ a few degrees only, in the ascending source, in january, march, may, and the beginning of june; it is therefore supplied with heat from a subterraneous source, being nearly twenty degrees above the mean temperature of the atmosphere. kircher has detailed in his "mundus subterraneus" various wonders respecting this lake, most of which are unfounded, such as that it is unfathomable, that it has at the bottom the heat of boiling water, and that floating islands rise from the gulf which emits it. it must certainly be very difficult, or even impossible, to fathom a source which rises with so much violence from a subterraneous excavation, and, at a time when chemistry had made small progress, it was easy to mistake the disengagement of carbonic acid for an actual ebullition. the floating islands are real, but neither the jesuit nor any of the writers who have since described this lake had a correct idea of their origin, which is exceedingly curious. the high temperature of this water, and the quantity of carbonic acid that it contains, render it peculiarly fitted to afford a pabulum or nourishment to vegetable life. the banks of travertine are everywhere covered with reeds, lichens, confervae, and various kinds of aquatic vegetables, and, at the same time that the process of vegetable life is going on, the crystallisations of the calcareous matter, which is everywhere deposited in consequence of the escape of carbonic acid, likewise proceed, giving a constant milkiness to what, from its tint, would otherwise be a blue fluid. so rapid is the vegetation, owing to the decomposition of the carbonic acid, that, even in winter, masses of confervae and lichens, mixed with deposited travertine, are constantly detached by the currents of water from the bank and float down the stream, which being a considerable river is never without many of these small islands on its surface; they are sometimes only a few inches in size, and composed merely of dark-green confervae or purple or yellow lichens, but they are sometimes even of some feet in diameter, and contain seeds and various species of common water-plants, which are usually more or less encrusted with marble. there is, i believe, no place in the world where there is a more striking example of the opposition or contrast of the laws of animate and inanimate nature, of the forces of inorganic chemical affinity and those of the powers of life. vegetables in such a temperature, and everywhere surrounded by food, are produced with a wonderful rapidity, but the crystallisations are formed with equal quickness, and they are no sooner produced than they are destroyed together. notwithstanding the sulphureous exhalations from the lake, the quantity of vegetable matter generated there and its heat make it the resort of an infinite variety of insect tribes, and even in the coldest days in winter numbers of flies may be observed on the vegetables surrounding its banks or on its floating island's, and a quantity of their larvae may be seen there sometimes encrusted and entirely destroyed by calcareous matter, which is likewise often the fate of the insects themselves, as well as of various species of shell-fish that are found amongst the vegetables, which grow and are destroyed in the travertine on its banks. snipes, ducks, and various water-birds, often visit those lakes, probably attracted by the temperature and the quantity of food in which they abound; but they usually confine themselves to the banks, as the carbonic acid disengaged from the surface would be fatal to them if they ventured to swim upon it when tranquil. in may, --, i fixed a stick on a mass of travertine covered by the water, and i examined it in the beginning of the april following for the purpose of determining the nature of the depositions. the water was lower at this time, yet i had some difficulty, by means of a sharp-pointed hammer, in breaking the mass which adhered to the bottom of the stick; it was several inches in thickness. the upper part was a mixture of light tufa and the leaves of confervae; below this was a darker and more solid travertine, containing black and decomposed masses of confervae; in the inferior part the travertine was more solid and of a grey colour, but with cavities which i have no doubt were produced by the decomposition of vegetable matter. i have passed many hours, i may say many days, in studying the phenomena of this wonderful lake; it has brought many trains of thought into my mind connected with the early changes of our globe, and i have sometimes reasoned from the forms of plants and animals preserved in marble in this warm source to the grander depositions in the secondary rocks, where the zoophytes or coral insects have worked upon a grand scale, and where palms, and vegetables now unknown are preserved with the remains of crocodiles, turtles, and gigantic extinct animals of the _sauri genus_, and which appear to have belonged to a period when the whole globe possessed a much higher temperature. i have, likewise, often been led, from the remarkable phenomena surrounding me in that spot, to compare the works of man with those of nature. the baths, erected there nearly twenty centuries ago, present only heaps of ruins, and even the bricks of which they were built, though hardened by fire, are crumbled into dust, whilst the masses of travertine around it, though formed by a variable source from the most perishable materials, have hardened by time, and the most perfect remains of the greatest ruins in the eternal city, such as the triumphal arches and the colosaeum, owe their duration to this source. then, from all we know, this lake, except in some change in its dimensions, continues nearly in the same state in which it was described , years ago by pliny, and i have no doubt contains the same kinds of floating islands, the same plants, and the same insects. during the fifteen years that i have known it it has appeared precisely identical in these respects, and yet it has the character of an accidental phenomenon depending upon subterraneous fire. how marvellous then are those laws by which even the humblest types of organic existence are preserved though born amidst the sources of their destruction, and by which a species of immortality is given to generations floating, as it were, like evanescent bubbles, on a stream raised from the deepest caverns of the earth, and instantly losing what may be called its spirit in the atmosphere." these last observations of the stranger recalled to my recollection some phenomena which i had observed many years ago, and of which i could then give no satisfactory explanation. i was shooting in the marshes which surround the ruins of gabia, and where there are still remains supposed to be of the alexandrine aqueduct; i observed a small insulated hill, apparently entirely composed of travertine, and from its summit there were formations of tufa which had evidently been produced by running water, but the whole mass was now perfectly dry and encrusted by vegetables. at first i suspected that this little mountain had been formed by a jet of calcareous water, a kind of small fountain analogous to the geiser, which had deposited travertine and continued to rise through the basin flowing from a higher level; but the irregular form of the eminence did not correspond to this idea, and i remained perplexed with the fact and unable to satisfy myself as to its cause. the views of the stranger appeared to me now to make it probable that the calcareous water had issued from ancient leaks in the aqueduct and formed a hillock that had encased the bricks of the erection, which in other parts, where not encrusted by travertine, had become entirely decayed, degraded, and removed from the soil. i mentioned the circumstance and my suspicion of its nature. the stranger said: "you are perfectly correct in your idea. i know the spot well, and if you had not mentioned it i should probably have quoted it as an instance in which the works of art are preserved, as it were, by the accidents of nature. i was so struck by this appearance last year that i had the travertine partially removed by some workmen, and i found beneath it the canal of the aqueduct in a perfect state, and the bricks of the arches as uninjured as if freshly laid." the stranger had hardly concluded this sentence when he was interrupted by onuphrio, who said, "i have always supposed that in every geological system water is considered as the cause of the destruction or degradation of the surface, but in all the instances that you have mentioned it appears rather as a conservative power, not destroying but rather producing." "it is the general vice of philosophical systems," replied the stranger, "that they are usually founded upon a few facts, which they well explain, and are extended by the human fancy to all the phenomena of nature, to many of which they must be contradictory. the human intellectual powers are so feeble that they can with difficulty embrace a single series of phenomena, and they consequently must fail when extended to the whole of nature. water by its common operation, as poured down from the atmosphere in rain and torrents, tends to level and degrade the surface, and carries the material of the land into the bosom of the ocean. fire, on the contrary, in volcanic eruptions usually raises mountains, exalts the surface, and creates islands even in the midst of the sea. but these laws are not invariable, as the instances to which we have just referred prove, and parts of the surface of the globe are sometimes destroyed even by fire, of which examples may be seen in the phlegraean fields, and islands raised by one volcanic eruption have been immerged in the sea by another. there are, in fact, no accidents in nature; what we call accidents are the results of general laws in particular operation, but we cannot deduce these laws from the particular operation or the general order from the partial result." ambrosio said to the stranger: "you appear, sir, to have paid so much attention to physical phenomena that few things would give us more pleasure than to know your opinion respecting the early changes and physical history of the globe, for i perceive you do not belong to the modern geological schools." the stranger said, "i have certainly formed opinions or rather speculations on these subjects, but i fear they are hardly worth communicating; they have sometimes amused me in hours of idleness, but i doubt if they will amuse others." i said, "the observations which you have already been so kind as to communicate to us, on the formation of the travertine, lead us not only to expect amusement but likewise instruction." _the stranger_.--on these matters i had facts to communicate; on the geological scheme of the early history of the globe there are only analogies to guide us, which different minds may apply and interpret in different ways; but i will not trifle with a long preliminary discourse. astronomical deductions and actual measures by triangulation prove that the globe is an oblate spheroid flattened at the poles, and this form we know, by strict mathematical demonstrations, is precisely the one which a fluid body revolving round its axis, and become solid at its surface by the slow dissipation of its heat or other causes, would assume. i suppose, therefore, that the globe, in the first state in which the imagination can venture to consider it, was a fluid mass with an immense atmosphere revolving in space round the sun, and that by its cooling a portion of its atmosphere was condensed in water which occupied a part of the surface. in this state no forms of life such as now belong to our system could have inhabited it; and, i suppose, the crystalline rocks (or, as they are called by geologists, the primary rocks), which contain no vestiges of a former order of things, were the results of the first consolidation on its surface. upon the further cooling the water which more or less had covered it contracted, depositions took place, shell- fish and coral insects of the first creation began their labours, and islands appeared in the midst of the ocean raised from the deep by the productive energies of millions of zoophytes. those islands became covered with vegetables fitted to bear a high temperature, such as palms and various species of plants similar to those which now exist in the hottest parts of the world; and the submarine rocks or shores of these new formations of land became covered with aquatic vegetables, on which various species of shell-fish and common fishes found their nourishment. the fluids of the globe in cooling deposited a large quantity of the materials they held in solution, and these deposits agglutinating together the sand, the immense masses of coral rocks, and some of the remains of the shells and fishes found round the shores of the primitive lands, produced the first order of secondary rocks. as the temperature of the globe became lower, species of the oviparous reptiles were created to inhabit it; and the turtle, crocodile, and various gigantic animals of the sauri kind, seem to have haunted the bays and waters of the primitive lands. but in this state of things there was no order of events similar to the present; the crust of the globe was exceedingly slender, and the source of fire a small distance from the surface. in consequence of contraction in one part of the mass, cavities were opened, which caused the entrance of water, and immense volcanic explosions took place, raising one part of the surface, depressing another, producing mountains, and causing new and extensive depositions from the primitive ocean. changes of this kind must have been extremely frequent in the early epochas of nature, and the only living forms of which the remains are found in the strata that are the monuments of these changes, are those of plants, fishes, birds, and oviparous reptiles, which seem most fitted to exist in such a war of the elements. when these revolutions became less frequent, and the globe became still more cooled, and the inequalities of its temperature preserved by the mountain chains, more perfect animals became its inhabitants, many of which, such as the mammoth, megalonix, megatherium, and gigantic hyena, are now extinct. at this period the temperature of the ocean seems to have been not much higher than it is at present, and the changes produced by occasional eruptions of it have left no consolidated rocks. yet one of these eruptions appears to have been of great extent and some duration, and seems to have been the cause of those immense quantities of water-worn stones, gravel and sand, which are usually called diluvian remains; and it is probable that this effect was connected with the elevation of a new continent in the southern hemisphere by volcanic fire. when the system of things became so permanent that the tremendous revolutions depending upon the destruction of the equilibrium between the heating and cooling agencies were no longer to be dreaded, the creation of man took place; and since that period there has been little alteration in the physical circumstances of our globe. volcanoes sometimes occasion the rise of new islands, portions of the old continent are constantly washed by rivers into the sea; but these changes are too insignificant to affect the destinies of man, or the nature of the physical circumstances of things. on the hypothesis that i have adopted, however, it must be remembered that the present surface of the globe is merely a thin crust surrounding a nucleus of fluid ignited matter, and consequently we can hardly be considered as actually safe from the danger of a catastrophe by fire. onuphrio said: "from the view you have taken, i conclude that you consider volcanic eruptions as owing to the central fire; indeed, their existence offers, i think, an argument for believing that the interior of the globe is fluid." the stranger answered: "i beg you to consider the views i have been developing as merely hypothetical, one of the many resting places that may be taken by the imagination in considering this subject. there are, however, distinct facts in favour of the idea that the interior of the globe has a higher temperature than the surface; the heat increasing in mines the deeper we penetrate, and the number of warm sources which rise from great depths in almost all countries, are certainly favourable to the idea. the opinion that volcanoes are owing to this general and simple cause is, i think, likewise more agreeable to the analogies of things than to suppose them dependent upon partial chemical changes, such as the action of air and water upon the combustible bases of the earths and alkalies, though it is extremely probable that these substances may exist beneath the surface, and may occasion some results of volcanic fire; and on this subject my notion may, perhaps, be more trusted, as for a long while i thought volcanic eruptions were owing to chemical agencies of the newly discovered metals of the earths and alkalies, and i made many, and some dangerous, experiments in the hope of confirming this notion, but in vain." _amb_.--we are very much obliged to you for your geological illustrations; but they remind me a little of some of the ideas of our friend philalethes in his remarkable vision, and with which we may at some time amuse you in return for your geology should we be honoured with more of your company. you are obliged to have recourse to creations for all the living beings in your philosophical romance. i do not see why you should not suppose creations or arrangements of dead matter by the same laws of infinite wisdom, and why our globe should not rise at once a divine work fitted for all the objects of living and intelligent natures. the stranger replied: "i have merely attempted a philosophical history founded upon the facts known respecting rocks and strata and the remains they contain. i begin with what may be considered a creation, a fluid globe supplied with an immense atmosphere, and the series of phenomena which i imagine consequent to the creation, i supposed produced by powers impressed upon matter by omnipotence." ambrosio said: "there is this verisimility in your history, that it is not contradictory to the little we are informed by revelation as to the origin of the globe, the order produced in the chaotic state, and the succession of living forms generated in the days of creation, which may be what philosophers call the 'epochas of nature,' for a day with omnipotence is as a thousand years, and a thousand years as one day." "i must object," onuphrio said, "to your interpretation of the scientific view of our new acquaintance, and to your disposition to blend them with the cosmogony of moses. allowing the divine origin of the book of genesis, you must admit that it was not intended to teach the jews systems of philosophy, but the laws of life and morals; and a great man and an exalted christian raised his voice two centuries ago against this mode of applying and of often wresting the sense of the scriptures to make them conformable to human fancies; 'from which,' says lord bacon, 'arise not only false and fantastical philosophies, but likewise heretical religions.' if the scriptures are to be literally interpreted and systems of science found in them, gallileo gallilei merited his persecution, and we ought still to believe that the sun turns round the earth." _amb_.--you mistake my view, onuphrio, if you imagine i am desirous of raising a system of geology on the book of genesis. it cannot be doubted that the first man was created with a great variety of instinctive or inspired knowledge, which must have been likewise enjoyed by his descendants; and some of this knowledge could hardly fail to have related to the globe which he inhabited, and to the objects which surrounded him. it would have been impossible for the human mind to have embraced the mysteries of creation, or to have followed the history of the moving atoms from their chaotic disorder into their arrangement in the visible universe, to have seen dead matter assuming the forms of life and animation, and light and power arising out of death and sleep. the ideas therefore transmitted to or presented by moses respecting the origin of the world and of man were of the most simple kind, and such as suited the early state of society; but, though general and simple truths, they were divine truths, yet clothed in a language and suited to the ideas of a rude and uninstructed people. and, when i state my satisfaction in finding that they are not contradicted by the refined researches of modern geologists, i do not mean to deduce from them a system of science. i believe that light was the creation of an act of the divine will; but i do not mean to say that the words, "let there be light, and there was light," were orally spoken by the deity, nor do i mean to imply that the modern discoveries respecting light are at all connected with this sublime and magnificent passage. _onu_.--having resided for a long time in edinburgh, and having heard a number of discussions on the theory of dr. hutton, or the plutonic theory of geology, and having been exceedingly struck both by its simplicity and beauty, its harmony with existing facts, and the proofs afforded to it by some beautiful chemical experiments, i do not feel disposed immediately to renounce it for the views which i have just heard explained; for the principal facts which our new acquaintance has stated are, i think, not inconsistent with the refined philosophical systems of professor playfair and sir james hall. _the unknown_.--i have no objection to the refined plutonic view, as capable of explaining many existing phenomena; indeed, you must be aware that i have myself had recourse to it. what i contend against is, its application to explain the formations of the secondary rocks, which i think clearly belong to an order of facts not at all embraced by it. in the plutonic system there is one simple and constant order assumed, which may be supposed eternal. the surface is constantly imagined to be disintegrated, destroyed, degraded, and washed into the bosom of the ocean by water, and as constantly consolidated, elevated, and regenerated by fire, and the ruins of the old form the foundations of the new world. it is supposed that there are always the same types, both of dead and living matter; that the remains of rocks, of vegetables, and animals of one age are found embedded in rocks raised from the bottom of the ocean in another. now, to support this view, not only the remains of living beings which at present people the globe might be expected to be found in the oldest secondary strata, but even those of the arts of man, the most powerful and populous of its inhabitants, which is well known not to be the case. on the contrary, each stratum of the secondary rocks contains remains of peculiar and mostly now unknown species of vegetables and animals. in those strata which are deepest, and which must consequently be supposed to be the earliest deposited, forms even of vegetable life are rare; shells and vegetable remains are found in the next order; the bones of fishes and oviparous reptiles exist in the following class; the remains of birds, with those of the same genera mentioned before, in the next order; those of quadrupeds of extinct species, in a still more recent class; and it is only in the loose and slightly consolidated strata of gravel and sand, and which are usually called diluvian formations, that the remains of animals such as now people the globe are found, with others belonging to extinct species. but in none of these formations, whether called secondary, tertiary, or diluvial, have the remains of man or any of his works been discovered. it is, i think, impossible to consider the organic remains found in any of the earlier secondary strata, the lias-limestone and its congenerous formations for instance, without being convinced that the beings, whose organs they formed, belonged to an order of things entirely different from the present. gigantic vegetables, more nearly allied to the palms of the equatorial countries than to any other plants, can only be imagined to have lived in a very high temperature; and the immense reptiles, the megalosauri with paddles instead of legs and clothed in mail, in size equal or even superior to the whale; and the great amphibia, plethiosauri, with bodies like turtles, but furnished with necks longer than their bodies, probably to enable them to feed on vegetables growing in the shallows of the primitive ocean, seem to show a state in which low lands or extensive shores rose above an immense calm sea, and when there were no great mountain, chains to produce inequalities of temperature, tempests, or storms. were the surface of the earth now to be carried down into the depths of the ocean, or were some great revolution of the waters to cover the existing land, and it was again to be elevated by fire, covered with consolidated depositions of sand or mud, how entirely different would it be in its characters from any of the secondary strata. its great features would undoubtedly be the works of man--hewn stones, and statues of bronze and marble, and tools of iron--and human remains would be more common than those of animals on the greatest part of the surface; the columns of paestum or of agrigentum, or the immense iron and granite bridges of the thames, would offer a striking contrast to the bones of the crocodiles or sauri in the older rocks, or even to those of the mammoth or elephas primogenius in the diluvial strata. and whoever dwells upon this subject must be convinced that the present order of things, and the comparatively recent existence of man as the master of the globe, is as certain as the destruction of a former and a different order and the extinction of a number of living forms which have now no types in being, and which have left their remains wonderful monuments of the revolutions of nature. _onu_.--i am not quite convinced by your arguments. supposing the lands of new holland were to be washed into the depths of the ocean, and to be raised according to the huttonian view, as a secondary stratum, by subterraneous fire, they would contain the remains of both vegetables and animals entirely different from any found in the strata of the old continents; and may not those peculiar formations to which you have referred be, as it were, accidents of nature belonging to peculiar parts of the globe? and you speak of a diluvian formation, which i conclude you would identify with that belonging to the catastrophe described in the sacred writings, in which no human remains are found. now, you surely will not deny that man existed at the time of this catastrophe, and he consequently may have existed at the period of the other revolutions, which are supposed to be produced in the huttonian views by subterraneous fire. _the unknown_.--i have made use of the term "diluvian," because it has been adopted by geologists, but without meaning to identify the cause of the formations with the deluge described in the sacred writings. i apply the term merely to signify loose and water-worn strata not at all consolidated, and deposited by an inundation of water, and in these countries which they have covered man certainly did not exist. with respect to your argument derived from new holland, it appears to me to be without weight. in a variety of climates, and in very distant parts of the globe, secondary strata of the same order are found, and they contain always the same kind of organic remains, which are entirely different from any of those now afforded by beings belonging to the existing order of things. the catastrophes which produced the secondary strata and diluvian depositions could not have been local and partial phenomena, but must have extended over the whole, or a great part of the surface, of the globe. the remains of similar shell-fishes are found in the limestones of the old and new continents; the teeth of the mammoth are not uncommon in various parts of europe; entire skeletons have been found in america, and even the skin covered with hair and the entire body of one of these enormous extinct animals has been discovered in siberia preserved in a mass of ice. in the oldest secondary strata there are no remains of such animals as now belong to the surface; and in the rocks which may be regarded as more recently deposited, these remains occur but rarely, and with abundance of extinct species. there seems, as it were, a gradual approach to the present system of things, and a succession of destructions and creations preparatory to the existence of man. it will be useless to push these arguments farther. you must allow that it is impossible to defend the proposition, that the present order of things is the ancient and constant order of nature, only modified by existing laws, and, consequently, the view which you have supported must be abandoned. the monuments of extinct generations of animals are as perfect as those of extinct nations; and it would be more reasonable to suppose that the pillars and temples of palmyra were raised by the wandering arabs of the desert, than to imagine that the vestiges of peculiar animated forms in the strata beneath the surface belonged to the early and infant families of the beings that at present inhabit it. _onu_.--i am convinced. i shall push my arguments no further, for i will not support the sophisms of that school which supposes that living nature has undergone gradual changes by the effects of its irritabilities and appetencies; that the fish has in millions of generations ripened into the quadruped, and the quadruped into the man; and that the system of life by its own inherent powers has fitted itself to the physical changes in the system of the universe. to this absurd, vague, atheistical doctrine, i prefer even the dream of plastic powers, or that other more modern dream, that the secondary strata were created, filled with remains, as it were, of animal life, to confound the speculations of our geological reasoners. _the unknown_.--i am glad you have not retreated into the desert and defenceless wilderness of scepticism, or of false and feeble philosophy. i should not have thought it worth my while to have followed you there; i should as soon think of arguing with the peasant who informs me that the basaltic columns of antrim or of staffa were the works of human art and raised by the giant finmacoul. at this moment, one of our servants came to inform me that a dinner which had been preparing for us at the farmhouse was ready; we asked the stranger to do us the honour to partake of our repast; he assented, and the following conversation took place at table. _phil_.--in reflecting upon our discussions this morning, i cannot help being a little surprised at their nature; we have been talking only of geological systems, when a more natural subject for our conversation would have been these magnificent temples, and an inquiry into the race by whom they were raised and the gods to whom they wore dedicated. we are now treading on a spot which contains the bones of a highly civilised and powerful people; yet we are almost ignorant of the names they bore, and the period of their greatness is lost in the obscurity of time. _amb_.--there can be no doubt that the early inhabitants of this city were grecians and a maritime and commercial people; they have been supposed to belong to the sybarite race, and the roses producing flowers twice a year in the spring and autumn in ancient times here, might sanction the idea that this balmy spot was chosen by a colony who carried luxury and refinement to the highest pitch. _onu_.--to attempt to form any opinion with respect to the people that anciently inhabited these now deserted plains is useless and a vain labour. in the geological conversation which took place before dinner, some series of interesting facts were presented to us; and the monuments of nature, though they do not speak a distinct language, yet speak an intelligible one; but with respect to paestum, there is neither history nor tradition to guide us; and we shall do wisely to resume our philosophical inquiries, if we have not already exhausted the patience of our new guest by doubts or objections to his views. _the stranger_.--one of you referred in our conversation this morning to a vision, which had some relation to the subject of our discussion, and i was promised some information on this matter. i immediately gave a sketch of my vision, and of the opinions which had been expressed by ambrosio on the early history of man, and the termination of our discussions on religion. _the stranger_.--i agree with ambrosio in opinion on the subjects you have just mentioned. in my youth, i was a sceptic; and this i believe is usually the case with young persons given to general and discursive reading, and accustomed to adopt something like a mathematical form in their reasonings; and it was in considering the nature of the intellectual faculties of brutes, as compared with those of man, and in examining the nature of instinctive powers, that i became a believer. after i had formed the idea that revelation was to man in the place of an instinct, my faith constantly became stronger; and it was exalted by many circumstances i had occasion to witness in a journey that i made through egypt and a part of asia minor, and by no one more than by a very remarkable dream which occurred to me in palestine, and which, as we are now almost at the hour of the siesta, i will relate to you, though perhaps you will be asleep before i have finished it. i was walking along that deserted shore which contains the ruins of ptolemais, one of the most ancient ports of judaea. it was evening; the sun was sinking in the sea; i seated myself on a rock, lost in melancholy contemplations on the destinies of a spot once so famous in the history of man. the calm mediterranean, bright in the glowing light of the west, was the only object before me. "these waves," i said to myself, "once bore the ships of the monarch of jerusalem which were freighted with the riches of the east to adorn and honour the sanctuary of jehovah; here are now no remains of greatness or of commerce; a few red stones and broken bricks only mark what might have been once a flourishing port, and the citadel above, raised by the saracens, is filled with turkish soldiers." the janissary, who was my guide, and my servant, were preparing some food for me in a tent which had been raised for the purpose, and whilst waiting for their summons to my repast, i continued my reveries, which must gradually have ended in slumber. i saw a man approaching towards me, whom, at first, i took for my janissary, but as he came nearer i found a very different figure. he was a very old man with a beard as white as snow; his countenance was dark but paler than that of an arab, and his features stern, wild, and with a peculiar savage expression; his form was gigantic, but his arms were withered and there was a large scar on the left side of his face which seemed to have deprived him of an eye. he wore a black turban and black flowing robes, and there was a large chain round his waist which clanked as he moved. it occurred to me that he was one of the santons or sacred madmen so common in the east, and i retired as he approached towards me. he called out: "fly not, stranger; fear me not, i will not harm you. you shall hear my story, it may be useful to you." he spoke in arabic but in a peculiar dialect and to me new, yet i understood every word. "you see before you," he said, "a man who was educated a christian, but who renounced the worship of the one supreme god for the superstitions of the pagans. i became an apostate in the reign of the emperor julian, and i was employed by that sovereign to superintend the re-erection of the temple of jerusalem, by which it was intended to belie the prophecies and give the deathblow to the holy religion. history has informed you of the result: my assistants were most of them destroyed in a tremendous storm, i was blasted by lightning from heaven (he raised his withered hand to his face and eye), but suffered to live and expiate my crime in the flesh. my life has been spent in constant and severe penance, and in that suffering of the spirit produced by guilt, and is to be continued as long as any part of the temple of jupiter, in which i renounced my faith, remains in this place. i have lived through fifteen tedious centuries, but i trust in the mercies of omnipotence, and i hope my atonement is completed. i now stand in the dust of the pagan temple. you have just thrown the last fragment of it over the rock. my time is arrived, i come!" as he spake the last words, he rushed towards the sea, threw himself from the rock and disappeared. i heard no struggling, and saw nothing but a gleam of light from the wave that closed above him. i was now roused by the cries of my servant and of the janissary, who were shaking my arm, and who informed me that my sleep was so sound that they were alarmed for me. when i looked on the sea, there was the same light, and i seemed to see the very spot in the wave where the old man had sunk. i was so struck by the vision, that i asked if they had not seen something dash into the wave, and if they had not heard somebody speaking to me as they arrived. of course their answers were negative. in passing through jerusalem and in coasting the dead sea i had been exceedingly struck by the present state of judaea and the conformity of the fate of the jewish nation to the predictions of our saviour; i had likewise been reading gibbon's eulogy of julian, and his account of the attempts made by that emperor to rebuild the temple: so that the dream at such a time and in such a place was not an unnatural occurrence. yet it was so vivid, and the image of the subject of it so peculiar, that it long affected my imagination, and whenever i recurred to it, strengthened my faith. _onu_.--i believe all the narratives of apparitions and ghost stories are founded upon dreams of the same kind as that which occurred to you: an ideal representation of events in the local situation, in which the person is at the moment, and when the imaginary picture of the place in sleep exactly coincides with its reality in waking. _the stranger_.--i agree with you in your opinion. if my servant had not been with me, and my dream had been a little less improbable, it would have been difficult to have persuaded me that i had not been visited by an apparition. i mentioned the dream of brutus, and said, "his supposed evil genius appeared in his tent; had the philosophical hero dreamt that his genius had appeared to him in rome, there could have been no delusion." i cited the similar vision, recorded of dion before his death, by plutarch, of a gigantic female, one of the fates or furies, who was supposed to have been seen by him when reposing in the portico of his palace. i referred likewise to my own vision of the beautiful female, the guardian angel of my recovery, who always seemed to me to be present at my bedside. _amb_.--in confirmation of this opinion of onuphrio, i can mention many instances. i once dreamt that my door had been forced, that there were robbers in my room, and that one of them was actually putting his hand before my mouth to ascertain if i was sleeping naturally. i awoke at this moment, and was some minutes before i could be sure whether it was a dream or a reality. i felt the pressure of the bedclothes on my lips, and still in the fear of being murdered continued to keep my eyes closed and to breathe slowly, till, hearing nothing and finding no motion, i ventured to open my eyes; but even then, when i saw nothing, i was not sure that my impression was a dream till i had risen from my bed and ascertained that the door was still locked. _onu_.--i am the only one of the party unable to record any dreams of the vivid and peculiar nature you mention from my own experience; i conclude it is owing to the dulness of my imagination. i suppose the more intense power of reverie is a symptom of the poetical temperament; and perhaps, if i possessed more enthusiasm, i should always have possessed more of the religious instinct. to adopt the idea of philalethes of hereditary character, i fear my forefathers have not been correct in their faith. _amb_.--your glory will be greater in establishing a new character, and i trust even the conversation of this day has given you an additional reason to adopt _our_ faith. ambrosio spoke these words with an earnestness unusual in him, and with something of a tone which marked a zeal for proselytism, and at the same time he cast his eyes on the rosary which was suspended round the neck of the stranger, and said, "i hope i am not indiscreet in saying _our_ faith." _the stranger_.--i was educated in the ritual of the church of england; i belong to the church of christ; the rosary which you see suspended round my neck is a memorial of sympathy and respect for an illustrious man. i will, if you will allow me, give you the history of it, which, i think from the circumstances with which it is connected, you will not find devoid of interest. i was passing through france in the reign of napoleon, by the peculiar privilege granted to a scavan, on my road into italy. i had just returned from the holy land, and had in my possession two or three of the rosaries which are sold to pilgrims at jerusalem as having been suspended in the holy sepulchre. pius vii. was then in imprisonment at fontainebleau. by a special favour, on the plea of my return from the holy land, i obtained permission to see this venerable and illustrious pontiff. i carried with me one of my rosaries. he received me with great kindness. i tendered my services to execute any commissions, not political ones, he might think fit to entrust me with in italy, informing him that i was an englishman. he expressed his thanks, but declined troubling me. i told him i was just returned from the holy land, and bowing with great humility, offered to him my rosary from the holy sepulchre. he received it with a smile, touched it with his lips, gave his benediction over it, and returned it into my hands, supposing, of course, that i was a roman catholic. i had meant to present it to his holiness, but the blessing he had bestowed upon it and the touch of his lips, made it a precious relic to me and i restored it to my neck, round which it has ever since been suspended. he asked me some unimportant questions respecting the state of the christians at jerusalem; and on a sudden, turned the subject, much to my surprise, to the destruction of the french in russia, and in an exceedingly low tone of voice, as if afraid of being overheard, he said, "the _nefas_ has long been triumphant over the _fas_, but i do not doubt that the balance of things is even now restoring; that god will vindicate his church, clear his polluted altars, and establish society upon its permanent basis of justice and faith. we shall meet again. adieu!" and he gave me his paternal blessing. it was eighteen months after this interview, that i went out with almost the whole population of rome, to receive and welcome the triumphal entry of this illustrious father of the church into his capital. he was borne on the shoulders of the most distinguished artists, headed by canova; and never shall i forget the enthusiasm with which he was received--it is impossible to describe the shouts of triumph and of rapture sent up to heaven by every voice. and when he gave his benediction to the people, there was an universal prostration, a sobbing and marks of emotions of joy almost like the bursting of the heart. i heard, everywhere around me, cries of "the holy father! the most holy father! his restoration is the work of god!" i saw tears streaming from the eyes of almost all the women about me, many of them were sobbing hysterically, and old men were weeping as if they had been children. i pressed my rosary to my breast on this occasion, and repeatedly touched with my lips that part of it which had received the kiss of the most venerable pontiff. i preserve it with a kind of hallowed feeling, as the memorial of a man whose sanctity, firmness, meekness and benevolence are an honour to his church and to human nature; and it has not only been useful to me, by its influence upon my own mind, but it has enabled me to give pleasure to others, and has, i believe, been sometimes beneficial in insuring my personal safety. i have often gratified the peasants of apulia and calabria by presenting them to kiss a rosary from the holy sepulchre which had been hallowed by the touch of the lips and benediction of the pope; and it has been even respected by and procured me a safe passage through a party of brigands who once stopped me in the passes of the apennines. _onu_.--the use you have made of this relic puts me in mind of a device of a very ingenious geological philosopher now living. he was on etna and busily employed in making a collection of the lavas formed from the igneous currents of that mountain; the peasants were often troublesome to him, suspecting that he was searching for treasures. it occurred to him to make the following speech to them: "i have been a great sinner in my youth and, as a penance, i have made a vow to carry away with me pieces of every kind of stone found upon the mountain; permit me quietly to perform my pious duty, that i may receive absolution for my sins." the speech produced the desired effect; the peasants shouted, "the holy man! the saint!" and gave him every assistance in their power to enable him to carry off his burthen, and he made his ample collections with the utmost security and in the most agreeable manner. _the stranger_.--i do not approve of pious frauds even for philosophical purposes; my rosary excited in others the same kind of feeling which it excited in my own bosom, and which i hold to be perfectly justifiable, and of which i shall never be ashamed. _amb_.--you must have travelled in italy in very dangerous times; have you always been secure? _the stranger_.--always; i have owed my security, partly, as i have said, to my rosary, but more to my dress and my acquaintance with the dialect of the natives. i have always carried with me a peasant as a guide, who has been intrusted with the small sums of money i wanted for my immediate purposes, and my baggage has been little more than a cynic philosopher would have carried with him; and when i have been unable to walk, i have trusted myself to the conduct of a vetturino, a native of the province, with his single mule and caratella. the sun was now setting and the temple of neptune was glowing with its last purple rays. we were informed that our horses were waiting, and that it was time for us to depart to our lodgings at eboli. i asked the stranger to be our companion and to do us the honour to accept of a seat in our carriage. he declined the invitation, and said: "my bed is prepared in the casina here for this night, and to-morrow i proceed on a journey connected with scientific objects in the parts of calabria the scene of the terrible earthquakes of ." i held out my hand to him in parting; he gave it a strong and warm pressure, and said, "adieu! we shall meet again." dialogue the fourth. the proteus, or immortality. the impression made upon my mind by the stranger with whom we became acquainted at paestum was of the strongest and most extraordinary kind. the memory of his person, his dress, his manners, the accents of his voice, and the tone of his philosophy, for a long while haunted my imagination in a most unaccountable manner, and even formed a part of my dreams. it often occurred to me that this was not the first time that i had seen him; and i endeavoured, but in vain, to find some type or image of him in former scenes of my life. i continually made inquiries respecting him amongst my acquaintance, but i could never be sure that any of them knew him, or even had seen him. so great were his peculiarities, that he must have escaped observation altogether; for, had he entered the world at all, he must have made some noise in it. i expressed so much interest on this subject, that at last it became a source of ridicule amongst my acquaintance, who often asked me if i had not yet obtained news of my spirit-friend or ghost-seer. after my return from naples to rome, i was almost immediately recalled to england by a melancholy event--the death of a very near and dear relation--and i left my two friends, ambrosio and onuphrio, to pursue their travels, which were intended to be of some extent and duration. in my youth, and through the prime of manhood, i never entered london without feelings of pleasure and hope. it was to me as the grand theatre of intellectual activity, the field of every species of enterprise and exertion, the metropolis of the world of business, thought, and action. there i was sure to find the friends and companions of my youth, to hear the voice of encouragement and praise. there, society of the most refined kind offered daily its banquets to the mind with such variety that satiety had no place in them, and new objects of interest and ambition were constantly exciting attention either in politics, literature, or science. i now entered this great city in a very different tone of mind--one of settled melancholy; not merely produced by the mournful event which recalled me to my country, but owing, likewise, to an entire change in the condition of my physical, moral, and intellectual being. my health was gone, my ambition was satisfied, i was no longer excited by the desire of distinction; what i regarded most tenderly was in the grave, and, to take a metaphor derived from the change produced by time in the juice of the grape, my cup of life was no longer sparkling, sweet, and effervescent;--it had lost its sweetness without losing its power, and it had become bitter. after passing a few months in england and enjoying (as much as i could enjoy anything) the society of the few friends who still remained alive, the desire of travel again seized me. i had preserved amidst the wreck of time one feeling strong and unbroken: the love of natural scenery; and this, in advanced life, formed a principal motive for my plans of conduct and action. of all the climates of europe, england seems to me most fitted for the activity of the mind, and the least suited to repose. the alterations of a climate so various and rapid continually awake new sensations; and the changes in the sky from dryness to moisture, from the blue ethereal to cloudiness and fogs, seem to keep the nervous system in a constant state of disturbance. in the mild climate of nice, naples, or sicily, where even in winter it is possible to enjoy the warmth of the sunshine in the open air, beneath palm trees or amidst evergreen groves of orange trees covered with odorous fruit and sweet-scented leaves, mere existence is a pleasure, and even the pains of disease are sometimes forgotten amidst the balmy influence of nature, and a series of agreeable and uninterrupted sensations invite to repose and oblivion. but in the changeful and tumultuous atmosphere of england, to be tranquil is a labour, and employment is necessary to ward off the attacks of ennui. the english as a nation is pre-eminently active, and the natives of no other country follow their objects with so much force, fire, and constancy. and, as human powers are limited, there are few examples of very distinguished men living in this country to old age: they usually fail, droop, and die before they have attained the period naturally marked for the end of human existence. the lives of our statesmen, warriors, poets, and even philosophers offer abundant proofs of the truth of this opinion; whatever burns, consumes--ashes remain. before the period of youth is passed, grey hairs usually cover those brows which are adorned with the civic oak or the laurel; and in the luxurious and exciting life of the man of pleasure, their tints are not even preserved by the myrtle wreath or the garland of roses from the premature winter of time. in selecting the scenes for my new journey i was guided by my former experience. i know no country more beautiful than that which may be called the alpine country of austria, including the alps of the southern tyrol, those of illyria, the noric and the julian alps, and the alps of styria and salzburg. the variety of the scenery, the verdure of the meadows and trees, the depths of the valleys, the altitude of the mountains, the clearness and grandeur of the rivers and lakes give it, i think, a decided superiority over switzerland; and the people are far more agreeable. various in their costumes and manners, illyrians, italians, or germans, they have all the same simplicity of character, and are all distinguished by their love of their country, their devotion to their sovereign, the warmth and purity of their faith, their honesty, and (with very few exceptions) i may say their great civility and courtesy to strangers. in the prime of life i had visited this region in a society which afforded me the pleasures of intellectual friendship and the delights of refined affection; later i had left the burning summer of italy and the violence of an unhealthy passion, and had found coolness, shade, repose, and tranquillity there; in a still more advanced period i had sought for and found consolation, and partly recovered my health after a dangerous illness, the consequence of labour and mental agitation; there i had found the spirit of my early vision. i was desirous, therefore, of again passing some time in these scenes in the hope of re-establishing a broken constitution; and though this hope was a feeble one, yet at least i expected to spend a few of the last days of life more tranquilly and more agreeably than in the metropolis of my own country. nature never deceives us. the rocks, the mountains, the streams always speak the same language. a shower of snow may hide the verdant woods in spring, a thunderstorm may render the blue limpid streams foul and turbulent; but these effects are rare and transient: in a few hours or at least days all the sources of beauty are renovated. and nature affords no continued trains of misfortunes and miseries, such as depend upon the constitution of humanity; no hopes for ever blighted in the bud; no beings full of life, beauty, and promise taken from us in the prime of youth. her fruits are all balmy, bright, and sweet; she affords none of those blighted ones so common in the life of man and so like the fabled apples of the dead sea--fresh and beautiful to the sight, but when tasted full of bitterness and ashes. i have already mentioned the strong effect produced on my mind by the stranger whom i had met so accidentally at paestum; the hope of seeing him again was another of my motives for wishing to leave england, and (why, i know not) i had a decided presentiment that i was more likely to meet him in the austrian states than in england, his own country. for this journey i had one companion, an early friend and medical adviser. he had lived much in the world, had acquired a considerable fortune, had given up his profession, was now retired, and sought, like myself, in this journey repose of mind and the pleasures derived from natural scenery. he was a man of a very powerful and acute understanding, but had less of the poetical temperament than any person whom i had ever known with similar vivacity of mind. he was a severe thinker, with great variety of information, an excellent physiologist, and an accomplished naturalist. in his reasonings he adopted the precision of a geometer, and was always upon his guard against the influence of imagination. he had passed the meridian of life, and his health was weak, like my own, so that we were well suited as travelling companions, moving always slowly from place to place without hurry or fatigue. i shall call this friend eubathes. i will say nothing of the progress of our journey through france and germany; i shall dwell only upon that part of it which has still a strong interest for me, and where events occurred that i shall never forget. we passed into the alpine country of austria by lintz, on the danube, and followed the course of the traun to gmunden, on the traun see or lake of the traun, where we halted for some days. if i were disposed to indulge in minute picturesque descriptions i might occupy hours with details of the various characters of the enchanting scenery in this neighbourhood. the vales have that pastoral beauty and constant verdure which is so familiar to us in england, with similar enclosures and hedge-rows and fruit and forest trees. above are noble hills planted with beeches and oaks. mountains bound the view, here covered with pines and larches, there raising their marble crests capped with eternal snows above the clouds. the lower part of the traun see is always, even in the most rainy season, perfectly pellucid; and the traun pours out of it over ledges of rocks a large and magnificent river, beautifully clear and of the purest tint of the beryl. the fall of the traun, about ten miles below gmunden, was one of our favourite haunts. it is a cataract which, when the river is full, may be almost compared to that of schaffhausen for magnitude, and possesses the same peculiar characters of grandeur in the precipitous rush of its awful and overpowering waters, and of beauty in the tints of its streams and foam, and in the forms of the rocks over which it falls, and the cliffs and woods by which it is overhung. in this spot an accident, which had nearly been fatal to me, occasioned the renewal of my acquaintance in an extraordinary manner with the mysterious unknown stranger. eubathes, who was very fond of fly-fishing, was amusing himself by catching graylings for our dinner in the stream above the fall. i took one of the boats which are used for descending the canal or lock artificially cut in the rock by the side of the fall, on which salt and wood are usually transported from upper austria to the danube; and i desired two of the peasants to assist my servant in permitting the boat to descend by a rope to the level of the river below. my intention was to amuse myself by this rapid species of locomotion along the descending sluice. for some moments the boat glided gently along the smooth current, and i enjoyed the beauty of the moving scene around me, and had my eye fixed upon the bright rainbow seen upon the spray of the cataract above my head; when i was suddenly roused by a shout of alarm from my servant, and, looking round, i saw that the piece of wood to which the rope had been attached had given way, and the boat was floating down the river at the mercy of the stream. i was not at first alarmed, for i saw that my assistants were procuring long poles with which it appeared easy to arrest the boat before it entered the rapidly descending water of the sluice, and i called out to them to use their united force to reach the longest pole across the water that i might be able to catch the end of it in my hand. and at this moment i felt perfect security; but a breeze of wind suddenly came down the valley and blew from the nearest bank, the boat was turned by it out of the side current and thrown nearer to the middle of the river, and i soon saw that i was likely to be precipitated over the cataract. my servant and the boatmen rushed into the water, but it was too deep to enable them to reach the boat; i was soon in the white water of the descending stream, and my danger was inevitable. i had presence of mind enough to consider whether my chance of safety would be greater by throwing myself out of the boat or by remaining in it, and i preferred the latter expedient. i looked from the rainbow upon the bright sun above my head, as if taking leave for ever of that glorious luminary; i raised one pious aspiration to the divine source of light and life; i was immediately stunned by the thunder of the fall, and my eyes were closed in darkness. how long i remained insensible i know not. my first recollections after this accident were of a bright light shining above me, of warmth and pressure in different parts of my body, and of the noise of the rushing cataract sounding in my ears. i seemed awakened by the light from a sound sleep, and endeavoured to recall my scattered thoughts, but in vain; i soon fell again into slumber. from this second sleep i was awakened by a voice which seemed not altogether unknown to me, and looking upwards i saw the bright eye and noble countenance of the unknown stranger whom i had met at paestum. i faintly articulated: "i am in another world." "no," said the stranger, "you are safe in this; you are a little bruised by your fall, but you will soon be well; be tranquil and compose yourself. your friend is here, and you will want no other assistance than he can easily give you." he then took one of my hands, and i recognised the same strong and warm pressure which i had felt from his parting salute at paestum. eubathes, whom i now saw with an expression of joy and of warmth unusual to him, gave a hearty shake to the other hand, and they both said, "you must repose a few hours longer." after a sound sleep till the evening, i was able to take some refreshment, and found little inconvenience from the accident except some bruises on the lower part of the body and a slight swimming in the head. the next day i was able to return to gmunden, where i learnt from the unknown the history of my escape, which seemed almost miraculous to me. he said that he was often in the habit of combining pursuits of natural history with the amusements derived from rural sports and was fishing the day that my accident happened below the fall of the traun for that peculiar species of the large _salmo_ of the danube which, fortunately for me, is only to be caught by very strong tackle. he saw, to his very great astonishment and alarm, the boat and my body precipitated by the fall, and was so fortunate as to entangle his hooks in a part of my dress when i had been scarcely more than a minute under water, and by the assistance of his servant, who was armed with the gaff or curved hook for landing large fish, i was safely conveyed to the shore, undressed, put into a warm bed, and by the modes of restoring suspended animation, which were familiar to him, i soon recovered my sensibility and consciousness. i was desirous of reasoning with him and eubathes upon the state of annihilation of power and transient death which i had suffered when in the water; but they both requested me to defer those inquiries, which required too profound an exertion of thought, till the effects of the shock on my weak constitution were over and my strength was somewhat re- established: and i was the more contented to comply with their request as the unknown said it was his intention to be our companion for at least some days longer, and that his objects of pursuit lay in the very country in which we were making our summer tour. it was some weeks before i was sufficiently strong to proceed on our journey, for my frame was little fitted to bear such a trial as that which it had experienced; and, considering the weak state of my body when i was immerged in the water, i could hardly avoid regarding my recovery as providential, and the presence and assistance of the stranger as in some way connected with the future destiny and utility of my life. in the middle of august we pursued our plans of travel. we first visited those romantic lakes, hallsstadt, aussee, and toplitz see, which collect the melted snows of the higher mountains of styria to supply the unfailing sources of the traun. we visited that elevated region of the tyrol which forms the crest of the pusterthal, and where the same chains of glaciers send down streams to the drave and the adige, to the black sea and to the adriatic. we remained for many days in those two magnificent valleys which afford the sources of the save, where that glorious and abundant river rises, as it were, in the very bosom of beauty, leaping from its subterraneous reservoirs in the snowy mountains of terglou and manhardt in thundering cataracts amongst cliffs and woods into the pure and deep cerulean lakes of wochain and wurzen, and pursuing its course amidst pastoral meadows so ornamented with plants and trees as to look the garden of nature. the subsoil or strata of this part of illyria are entirely calcareous and full of subterranean caverns, so that in every declivity large funnel- shaped cavities, like the craters of volcanoes, may be seen, in which the waters that fall from the atmosphere are lost: and almost every lake or rives has a subterraneous source, and often a subterraneous exit. the laibach river rises twice from the limestone rock, and is twice again swallowed up by the earth before it makes its final appearance and is lost in the save. the zirknitz see or lake is a mass of water entirely filled and emptied by subterraneous sources, and its natural history, though singular, has in it nothing of either prodigy, mystery, or wonder. the grotto of the maddalena at adelsberg occupied more of our attention than the zirknitz see. i shall give the conversation that took place in that extraordinary cavern entire, as well as i can remember it, in the words used by my companions. _eub_.--we must be many hundred feet below the surface, yet the temperature of this cavern is fresh and agreeable. _the unknown_.--this cavern has the mean temperature of the atmosphere, which is the case with all subterraneous cavities removed from the influence of the solar light and heat; and, in so hot a day in august as this, i know no more agreeable or salutary manner of taking a cold bath than in descending to a part of the atmosphere out of the influence of those causes which occasion its elevated temperature. _eub_.--have you, sir, been in this country before? _the unknown_.--this is the third summer that i have made it the scene of an annual visit. independently of the natural beauties found in illyria, and the various sources of amusement which a traveller fond of natural history may find in this region, it has had a peculiar object of interest for me in the extraordinary animals which are found in the bottom of its subterraneous cavities: i allude to the proteus anguinus, a far greater wonder of nature than any of those which the baron valvasa detailed to the royal society a century and half ago as belonging to carniola, with far too romantic an air for a philosopher. _phil_.--i have seen these animals in passing through this country before; but i should be very glad to be better acquainted with their natural history. _the unknown_.--we shall soon be in that part of the grotto where they are found, and i shall willingly communicate the little that i have been able to learn respecting their natural characters and habits. _eub_.--the grotto now becomes really magnificent; i have seen no subterraneous cavity with so many traits of beauty and of grandeur. the irregularity of its surface, the magnitude of the masses broken in pieces which compose its sides, and which seem torn from the bosom of the mountain by some great convulsion of nature, their dark colours and deep shades form a singular contrast with the beauty, uniformity, i may say, order and grace of the white stalactical concretions which hang from the canopy above, and where the light of our torches reflected from the brilliant or transparent calcareous gems create a scene which almost looks like one produced by enchantment. _phil_.--if the awful chasms of dark masses of rock surrounding us appear like the work of demons who might be imagined to have risen from the centre of the earth, the beautiful works of nature above our heads may be compared to a scenic representation of a temple or banquet hall for fairies or genii, such as those fabled in the arabian romances. _the unknown_.--a poet might certainly place here the palace of the king of the gnomes, and might find marks of his creative power in the small lake close by on which the flame of the torch is now falling, for there it is that i expect to find the extraordinary animals which have been so long the objects of my attention. _eub_.--i see three or four creatures, like slender fish, moving on the mud below the water. _the unknown_.--i see them; they are the protei. now i have them in my fishing-net, and now they are safe in the pitcher of water. at first view you might suppose this animal to be a lizard, but it has the motions of a fish. its head and the lower part of its body and its tail bear a strong resemblance to those of the eel; but it has no fins, and its curious bronchial organs are not like the gills of fishes: they form a singular vascular structure, as you see, almost like a crest, round the throat, which may be removed without occasioning the death of the animal, which is likewise furnished with lungs. with this double apparatus for supplying air to the blood, it can live either below or above the surface of the water. its fore-feet resemble hands, but they have only three claws or fingers, and are too feeble to be of use in grasping or supporting the weight of the animal; the hinder feet have only two claws or toes, and in the larger specimens are found so imperfect as to be almost obliterated. it has small points in place of eyes, as if to preserve the analogy of nature. it is of a fleshy whiteness and transparency in its natural state; but when exposed to light, its skin gradually becomes darker, and at last gains an olive tint. its nasal organs appear large, and it is abundantly furnished with teeth: from which it may be concluded that it is an animal of prey; yet in its confined state it has never been known to eat, and it has been kept alive for many years by occasionally changing the water in which it was placed. _eub_.--is this the only place in carniola where these animals are found? _the unknown_.--they were first discovered here by the late baron zois; but they have since been found, though rarely, at sittich, about thirty miles distant, thrown up by water from a subterraneous cavity; and i have lately heard it reported that some individuals of the same species have been recognised in the calcareous strata in sicily. _eub_.--this lake in which we have seen these animals is a very small one. do you suppose they are bred here? _the unknown_.--certainly not. in dry seasons they are seldom found here, but after great rains they are often abundant. i think it cannot be doubted that their natural residence is in an extensile deep subterranean lake, from which in great floods they sometimes are forced through the crevices of the rocks into this place where they are found; and it does not appear to me impossible, when the peculiar nature of the country in which we are is considered, that the same great cavity may furnish the individuals which have been found at adelsberg and at sittich. _eub_.--this is a very extraordinary view of the subject. is it not possible that it may be the larva of some large unknown animal inhabiting these limestone cavities? its feet are not in harmony with the rest of its organisation; and were they removed, it would have all the characters of a fish. _the unknown_.--i cannot suppose that they are larvae. there is, i believe, in nature no instance of a transition by this species of metamorphosis from a more perfect to a less perfect animal. the tadpole has a resemblance to a fish before it becomes a frog; the caterpillar and the maggot gain not only more perfect powers of motion on the earth in their new state, but acquire organs by which they inhabit a new element. this animal, i dare say, is much larger than we now see it when mature in its native place; but its comparative anatomy is exceedingly hostile to the idea that it is an animal in a state of transition. it has been found of various sizes, from that of the thickness of a quill to that of the thumb, but its form of organs has been always the same. it is surely a perfect animal of a peculiar species. and it adds one instance more to the number already known of the wonderful manner in which life is produced and perpetuated in every part of our globe, even in places which seem the least suited to organised existences. and the same infinite power and wisdom which has fitted the camel and the ostrich for the deserts of africa, the swallow that secretes its own nest for the caves of java, the whale for the polar seas, and the morse and white bear for the arctic ice, has given the proteus to the deep and dark subterraneous lakes of illyria--an animal to whom the presence of light is not essential, and who can live indifferently in air and in water, on the surface of the rock, or in the depths of the mud. _phil_.--it is now ten years since i first visited this spot. i was exceedingly anxious to see the proteus, and came here with the guide in the evening of the day i arrived at adelsberg; but though we examined the bottom of the cave with the greatest care, we could find no specimens. we returned the next morning and were more fortunate, for we discovered five close to the bank on the mud covering the bottom of the lake; the mud was smooth and perfectly undisturbed, and the water quite clear. this fact of their appearance during the night seemed to me so extraordinary, that i could hardly avoid the fancy that they were new creations. i saw no cavities through which they could have entered, and the undisturbed state of the lake seemed to give weight to my notion. my reveries became discursive; i was carried in imagination back to the primitive state of the globe, when the great animals of the sauri kind were created under the pressure of a heavy atmosphere; and my notion on this subject was not destroyed when i heard from a celebrated anatomist, to whom i sent the specimens i had collected, that the organisation of the spine of the proteus was analogous to that of one of the sauri, the remains of which are found in the older secondary strata. it was said at this time that no organs of reproduction had been discovered in any of the specimens examined by physiologists, and this lent a weight to my opinion of the possibility of their being actually new creations, which i suppose you will condemn as wholly visionary and unphilosophical. _eub_.--from the tone in which you make your statements, i think you yourself consider them as unworthy of discussion. on such ground eels might be considered new creations, for their mature ovaria have not yet been discovered, and they come from the sea into rivers under circumstances when it is difficult to trace their course. _the unknown_.--the problem of the reproduction of the proteus, like that of the common eel, is not yet solved; but ovaria have been discovered in animals of both species, and in this instance, as in all others belonging to the existing order of things, harvey's maxim of "omne vivum ab ovo" will apply. _eub_.--you just now said that this animal has been long an object of attention to you; have you studied it as a comparative anatomist, in search of the solution of the problem of its reproduction? _the unknown_.--no; this inquiry has been pursued by much abler investigators: by schreiber and configliachi; my researches were made upon its respiration and the changes occasioned in water by its bronchia. _eub_.--i hope they have been satisfactory. _the unknown_.--they proved to me, at least, that not merely the oxygen dissolved in water, but likewise a part of the azote, was absorbed in the respiration of this animal. _eub_.--so that your researches confirm those of the french savants and alexander von humboldt, that in the respiration of animals which separate air from water, both principles of the atmosphere are absorbed. _phil_.--i have heard so many and such various opinions on the nature of the function of respiration during my education and since, that i should like to know what is the modern doctrine on this subject. i can hardly refer to better authority than yourself, and i have an additional reason for wishing for some accurate knowledge on this matter, having, as you well know, been the subject of an experiment in relation to it which, but for your kind and active assistance, must have terminated fatally. _the unknown_.--i shall gladly state what i know, which is very little. in physics and in chemistry, the science of dead matter, we possess many facts and a few principles or laws; but whenever the functions of life are considered, though the facts are numerous, yet there is, as yet, scarcely any approach to general laws, and we must usually end where we begin by confessing our entire ignorance. _eub_.--i will not allow this ignorance to be entire. something, undoubtedly, has been gained by the knowledge of the circulation of the blood and its aeration in the lungs--these, if not laws, are at least fundamental principles. _the unknown_.--i speak only of the functions in their connection with life. we are still ignorant of the source of animal heat, though half a century ago the chemists thought they had proved it was owing to a sort of combustion of the carbon of the blood. _phil_.--as we return to our inn i hope you will both be so good as give me your views of the nature of this function, so important to all living things; tell me what you _know_, or what you _believe_, or what others _imagine they know_. _the unknown_.--the powers of the organic system depend upon a continued state of change. the waste of the body produced in muscular action, perspiration, and various secretions, is made up for by the constant supply of nutritive matter to the blood by the absorbents, and by the action of the heart the blood is preserved in perpetual motion through every part of the body. in the lungs, or bronchia, the venous blood is exposed to the influence of air and undergoes a remarkable change, being converted into arterial blood. the obvious chemical alteration of the air is sufficiently simple in this process: a certain quantity of carbon only is added to it, and it receives an addition of heat or vapour; the volumes of elastic fluid inspired and expired (making allowance for change of temperature) are the same, and if ponderable agents only were to be regarded it would appear as if the only use of respiration were to free the blood from a certain quantity of carbonaceous matter. but it is probable that this is only a secondary object, and that the change produced by respiration upon the blood is of a much more important kind. oxygen, in its elastic state, has properties which are very characteristic: it gives out light by compression, which is not certainly known to be the case with any other elastic fluid except those with which oxygen has entered without undergoing combustion; and from the fire it produces in certain processes, and from the manner in which it is separated by positive electricity in the gaseous state from its combinations, it is not easy to avoid the supposition that it contains, besides its ponderable elements, some very subtle matter which is capable of assuming the form of heat and light. my idea is that the common air inspired enters into the venous blood entire, in a state of dissolution, carrying with it its subtle or ethereal part, which in ordinary cases of chemical change is given off; that it expels from the blood carbonic acid gas and azote; and that in the course of the circulation its ethereal part and its ponderable part undergo changes which belong to laws that cannot be considered as chemical--the ethereal part probably producing animal heat and other effects, and the ponderable part contributing to form carbonic acid and other products. the arterial blood is necessary to all the functions of life, and it is no less connected with the irritability of the muscles and the sensibility of the nerves than with the performance of all the secretions. _eub_.--no one can be more convinced than i am of the very limited extent of our knowledge in chemical physiology, and when i say that, having been a disciple and friend of dr. black, i am still disposed to prefer his ancient view to your new one, i wish merely to induce you to pause and to hear my reasons; they may appear insufficient to you, but i am anxious to explain them. first, then, in all known chemical changes in which oxygen gas is absorbed and carbonic acid gas formed, heat is produced. i could mention a thousand instances, from the combustion of wood or spirits of wine to the fermentation of fruit or the putrefaction of animal matter. this general fact, which may be almost called a law, is in favour of the view of dr. black. another circumstance in favour of it is, that those animals which possess the highest temperature consume the greatest quantity of air, and, under different circumstances of action and repose, the heat is in great measure proportional to the quantity of oxygen consumed. then those animals which absorb the smallest quantity of air are cold-blooded. another argument in favour of dr. black's opinion is the change of colour of blood from black to red, which seems to show that it loses carbon. _the unknown_.--with the highest respect for the memory of dr. black, and for the opinion of his disciple, i shall answer the arguments i have just heard. i will not allow any facts or laws from the action of dead matter to apply to living structures; the blood is a living fluid, and of this we are sure that it does not burn in respiration. the terms warmth and cold, as applied to the blood of animals, are improper in the sense in which they have been just used; all animals are, in fact, warm-blooded, and the degrees of their temperature are fitted to the circumstances under which they live, and those animals, the life of which is most active, possess most heat, which may be the result of general actions, and not a particular effect of respiration. besides, a distinguished physiologist has rendered it probable that the animal heat depends more upon the functions of the nerves than upon any result of respiration. the argument derived from change of colour is perfectly delusive; it would not follow if carbon were liberated from the blood that it must necessarily become brighter; sulphur combining with charcoal becomes a clear fluid, and a black oxide of copper becomes red in uniting with a substance which abounds in carbon. no change in sensible qualities can ever indicate with precision the nature of chemical change. i shall resume my view, which i cannot be said to have fully developed. when i stated that carbonic acid was formed in the venous blood in the processes of life, i meant merely to say that this blood, in consequence of certain changes, became capable of giving off carbon and oxygen in union with each other, for the moment inorganic matter enters into the composition of living organs it obeys new laws. the action of the gastric juice is chemical, and it will only dissolve dead matters, and it dissolves them when they are in tubes of metal as well as in the stomach, but it has no action upon living matter. respiration is no more a chemical process than the absorption of chyle; and the changes that take place in the lungs, though they appear so simple, may be very complicated; it is as little philosophical to consider them as a mere combustion of carbon as to consider the formation of muscle from the arterial blood as crystallisation. there can be no doubt that all the powers and agencies of matter are employed in the purposes of organisation, but the phenomena of organisation can no more be referred to chemistry than those of chemistry to mechanics. as oxygen stands in that electrical relation to the other elements of animal matter which has been called electropositive, it may be supposed that some electrical function is exercised by oxygen in the blood; but this is a mere hypothesis. an attempt has been made founded on experiments on the decomposition of bodies by electricity to explain secretion by weak electrical powers, and to suppose the glands electrical organs, and even to imagine the action of the nerves dependent upon electricity; these, like all other notions of the same kind, appear to me very little refined. if electrical effects be the exhibition of certain powers belonging to matter, which is a fair supposition, then no change can take place without their being more or less concerned; but to imagine the presence of electricity to solve phenomena the cause of which is unknown is merely to substitute one undefined word for another. in some animals electrical organs are found, but then they furnish the artillery of the animal and means of seizing its prey and of its defence. and speculations of this kind must be ranked with those belonging to some of the more superficial followers of the newtonian philosophy, who explained the properties of animated nature by mechanical powers, and muscular action by the expansion and contraction of elastic bladders; man, in this state of vague philosophical inquiry, was supposed a species of hydraulic machine. and when the pneumatic chemistry was invented, organic structures were soon imagined to be laboratories in which combinations and decompositions produced all the effects of living actions; then muscular contractions were supposed to depend upon explosions like those of the detonating compounds, and the formation of blood from chyle was considered as a pure chemical solution. and, now that the progress of science has opened new and extraordinary views in electricity, these views are not unnaturally applied by speculative reasoners to solve some of the mysterious and recondite phenomena of organised beings. but the analogy is too remote and incorrect; the sources of life cannot be grasped by such machinery; to look for them in the powers of electro-chemistry is seeking the living among the dead: that which touches will not be felt, that which sees will not be visible, that which commands sensations will not be their subject. _phil_.--i conclude, from what you last said, that though you are inclined to believe that some unknown subtle matter is added to the organised system by respiration, yet you would not have us believe that this is electricity, or that there is any reason to suppose that electricity has a peculiar and special share in producing the functions of life. _the unknown_.--i wish to guard you against the adoption of any hypothesis on this recondite and abstruse subject. but however difficult it may be to define the exact nature of respiration, yet the effect of it and its connexions with the functions of the body are sufficiently striking. by the action of air on the blood it is fitted for the purposes of life, and from the moment that animation is marked by sensation or volition, this function is performed, the punctum saliens in the ovum seems to receive as it were the breath of life in the influence of air. in the economy of the reproduction of the species of animals, one of the most important circumstances is the aeration of the ovum, and when this is not performed, from the blood of the mother as in the mammalia by the placenta, there is a system for aerating as in the oviparous reptiles or fishes, which enables the air freely to pass through the receptacles in which the eggs are deposited, or the egg itself is aerated out of the body through its coats or shell, and when air is excluded, incubation or artificial heat has no effect. fishes which deposit their eggs in water that contains only a limited portion of air, make combinations which would seem almost the result of scientific knowledge or reason, though depending upon a more unerring principle, their instinct for preserving their offspring. those fishes that spawn in spring or the beginning of summer and winch inhabit deep and still waters, as the carp, bream, pike, tench, &c., deposit their eggs upon aquatic vegetables, which by the influence of the solar light constantly preserve the water in a state of aeration. the trout, salmon, hucho, and others of the salmo genus, which spawn in the beginning or end of winter, and which inhabit rivers fed by cold and rapid streams which descend from the mountains, deposit their eggs in shallows on heaps of gravel, as near as possible to the source of the stream where the water is fully combined with air; and to accomplish this purpose they travel for hundreds of miles against the current, and leap over cataracts and dams: thus the salmo salar ascends by the rhone and the aar to the glaciers of switzerland, the hucho by the danube, the isar, and the save, passing through the lakes of the tyrol and styria to the highest torrents of the noric and julian alps. _phil_.--my own experience proves in the strongest manner the immediate connection of sensibility with respiration; all that i can remember in my accident was a certain violent and painful sensation of oppression in the chest, which must have been immediately succeeded by loss of sense. _eub_.--i have no doubt that all your suffering was over at the moment you describe; as far as sensibility is concerned, you were inanimate when your friend raised you from the bottom. this distinct connection of sensibility with the absorption of air by the blood is, i think, in favour of the idea advanced by our friend, that some subtle and ethereal matter is supplied to the system in the elastic air which may be the cause of vitality. _the unknown_.--softly, if you please; i must not allow you to mistake my view. i think it probable that some subtle matter is derived from the atmosphere connected with the functions of life; but nothing can be more remote from my opinion than to suppose it the cause of vitality. _phil_.--this might have been fully inferred from the whole tenor of your conversation, and particularly from that expression, "that which commands sensation will not be their subject." i think i shall not mistake your views when i say that you do not consider vitality dependent upon any material cause or principle. _the unknown_.--you do not. we are entirely ignorant on this subject, and i confess in the utmost humility my ignorance. i know there have been distinguished physiologists who have imagined that by organisation powers not naturally possessed by matter were developed, and that sensibility was a property belonging to some unknown combination of unknown ethereal elements. but such notions appear to me unphilosophical, and the mere substitution of unknown words for unknown things. i can never believe that any division, or refinement, or subtilisation, or juxtaposition, or arrangement of the particles of matter, can give to them sensibility; or that intelligence can result from combinations of insensate and brute atoms. i can as easily imagine that the planets are moving by their will or design round the sun, or that a cannon ball is reasoning in making its parabolic curve. the materialists have quoted a passage of locke in favour of their doctrine, who seemed to doubt "whether it might not have pleased god to bestow a power of thinking on matter." but with the highest veneration for this great reasoner, the founder of modern philosophical logic, i think there is little of his usual strength of mind in this doubt. it appears to me that he might as well have asked whether it might not have pleased god to make a house its own tenant. _eub_.--i am not a professed materialist; but i think you treat rather too lightly the modest doubts of locke on this subject. and without considering me as a partisan, you will, i hope, allow me to state some of the reasons which i have heard good physiologists advance in favour of that opinion to which you are so hostile. in the first accretion of the parts of animated beings they appear almost like the crystallised matter, with the simplest kind of life, scarcely sensitive. the gradual operations by which they acquire new organs and new powers, corresponding to these organs, till they arrive at full maturity, forcibly strikes the mind with the idea that the powers of life reside in the arrangement by which the organs are produced. then, as there is a gradual increase of power corresponding to the increase of perfection of the organisation, so there is a gradual diminution of it connected with the decay of the body. as the imbecility of infancy corresponds to the weakness of organisation, so the energy of youth and the power of manhood are marked by its strength; and the feebleness and dotage of old age are in the direct ratio of the decline of the perfection of the organisation, and the mental powers in extreme old age seem destroyed at the same time with the corporeal ones, till the ultimate dissolution of the frame, when the elements are again restored to that dead nature from which they were originally derived. then, there was a period when the greatest philosopher, statesman, or hero, that ever existed was a mere living atom, an organised form with the sole power of perception; and the combinations that a newton formed before birth or immediately after cannot be imagined to have possessed the slightest intellectual character. if a peculiar principle be supposed necessary to intelligence, it must exist throughout animated nature. the elephant approaches nearer to man in intellectual power than the oyster does to the elephant; and a link of sensitive nature may be traced from the polypus to the philosopher. now, in the polypus the sentient principle is divisible, and from one polypus or one earthworm may be formed two or three, all of which become perfect animals, and have perception and volition; therefore, at least, the sentient principle has this property in common with matter, that it is divisible. then to these difficulties add the dependence of all the higher faculties of the mind upon the state of the brain; remember that not only all the intellectual powers, but even sensibility is destroyed by the pressure of a little blood upon the cerebellum, and the difficulties increase. call to mind likewise the suspension of animation in cases similar to that of our friend, when there are no signs of life and when animation returns only with the return of organic action. surely in all these instances everything which you consider as belonging to spirit appears in intimate dependence upon the arrangements and properties of matter. _the unknown_.--the arguments you have used are those which are generally employed by physiologists. they have weight in appearance, but not in reality. they prove that a certain perfection of the machinery of the body is essential to the exercise of the powers of the mind, but they do not prove that the machine is the mind. without the eye there can be no sensations of vision, and without the brain there could be no recollected visible ideas; but neither the optic nerve nor the brain can be considered as the percipient principle--they are but the instruments of a power which has nothing in common with them. what may be said of the nervous system may be applied to a different part of the frame; stop the motion of the heart, and sensibility and life cease, yet the living principle is not in the heart, nor in the arterial blood which it sends to every part of the system. a savage who saw the operation of a number of power-looms weaving stockings cease at once on the stopping of the motion of a wheel, might well imagine that the motive force was in the wheel; he could not divine that it more immediately depended upon the steam, and ultimately upon a fire below a concealed boiler. the philosopher sees the fire which is the cause of the motion of this complicated machinery, so unintelligible to the savage; but both are equally ignorant of the divine fire which is the cause of the mechanism of organised structures. profoundly ignorant on this subject, all that we can do is to give a history of our own minds. the external world or matter is to us in fact nothing but a heap or cluster of sensations; and, in looking back to the memory of our own being, we find one principle, which may be called the _monad_, or _self_, constantly present, intimately associated with a particular class of sensations, which we call our own body or organs. these organs are connected with other sensations, and move, as it were, with them in circles of existence, quitting for a time some trains of sensation to return to others; but the monad is always present. we can fix no beginning to its operations; we can place no limit to them. we sometimes, in sleep, lose the beginning and end of a dream, and recollect the middle of it, and one dream has no connection with another; and yet we are conscious of an infinite variety of dreams, and there is a strong analogy for believing in an infinity of past existences, which must have had connection; and human life may be regarded as a type of infinite and immortal life, and its succession of sleep and dreams as a type of the changes of death and birth to which from its nature it is liable. that the ideas belonging to the mind were originally gained from those classes of sensations called organs it is impossible to deny, as it is impossible to deny that mathematical truths depend upon the signs which express them; but these signs are not themselves the truths, nor are the organs the mind. the whole history of intellect is a history of change according to a certain law; and we retain the memory only of those changes which may be useful to us--the child forgets what happened to it in the womb; the recollections of the infant likewise before two years are soon lost, yet many of the habits acquired in that age are retained through life. the sentient principle gains thoughts by material instruments, and its sensations change as those instruments change; and, in old age, the mind, as it were, falls asleep to awake to a new existence. with its present organisation, the intellect of man is naturally limited and imperfect, but this depends upon its material machinery; and in a higher organised form, it may be imagined to possess infinitely higher powers. were man to be immortal with his present corporeal frame, this immortality would only belong to the machinery; and with respect to acquisitions of mind, he would virtually die every two or three hundred years--that is to say, a certain quantity of ideas only could be remembered, and the supposed immortal being would be, with respect to what had happened a thousand years ago, as the adult now is with respect to what happened in the first year of his life. to attempt to reason upon the manner in which the organs are connected with sensation would be useless; the nerves and brain have some immediate relation to these vital functions, but how they act it is impossible to say. from the rapidity and infinite variety of the phenomena of perception, it seems extremely probable that there must be in the brain and nerves matter of a nature far more subtle and refined than anything discovered in them by observation and experiment, and that the immediate connection between the sentient principle and the body may be established by kinds of ethereal matter, which can never be evident to the senses, and which may bear the same relations to heat, light, and electricity that these refined forms or modes of existence of matter bear to the gases. motion is most easily produced by the lighter species of matter; and yet imponderable agents, such as electricity, possess force sufficient to overturn the weightiest structures. nothing can be farther from my meaning than to attempt any definition on this subject, nor would i ever embrace or give authority to that idea of newton, who supposes that the immediate cause of sensation may be in undulations of an ethereal medium. it does not, however, appear improbable to me that some of the more refined machinery of thought may adhere, even in another state, to the sentient principle; for, though the organs of gross sensation--the nerves and brain--are destroyed by death, yet something of the more ethereal nature, which i have supposed, may be less destructible. and i sometimes imagine that many of those powers, which have been called instinctive, belong to the more refined clothing of the spirit; conscience, indeed, seems to have some undefined source, and may bear relation to a former state of being. _eub_.--all your notions are merely ingenious speculations. revelation gives no authority to your ideas of spiritual nature; the christian immortality is founded upon the resurrection of the body. _the unknown_.--this i will not allow. even in the mosaic history of the creation of man his frame is made in the image of god--that is, capable of intelligence; and the creator breathes into it the breath of life, his own essence. then our saviour has said, "of the god of abraham, of isaac, and of jacob." "he is not the god of the dead, but of the living." st. paul has described the clothing of the spirit in a new and glorious body, taking the analogy from the living germ in the seed of the plant, which is not quickened till after apparent death; and the catastrophe of our planet, which, it is revealed, is to be destroyed and purified by fire before it is fitted for the habitation of the blest, is in perfect harmony with the view i have ventured to suggest. _eub_.--i cannot make your notions coincide with what i have been accustomed to consider the meaning of holy writ. you allow everything belonging to the material life to be dependent upon the organisation of the body, and yet you imagine the spirit after death clothed with a new body; and, in the system of rewards and punishments, this body is rendered happy or miserable for actions committed by another and extinct frame. a particular organisation may impel to improper and immoral gratification; it does not appear to me, according to the principles of eternal justice, that the body of the resurrection should be punished for crimes dependent upon a conformation now dissolved and destroyed. _the unknown_.--nothing is more absurd, i may say more impious, than for man, with a ken surrounded by the dense mists of sense, to reason respecting the decrees of eternal justice. you adopt here the same limited view that you embraced in reasoning against the indestructibility of the sentient principle in man from the apparent division of the living principle in the polypus, not recollecting that to prove a quality can be increased or exalted does not prove that it can be annihilated. if there be, which i think cannot be doubted, a consciousness of good and evil constantly belonging to the sentient principle in man, then rewards and punishments naturally belong to acts of this consciousness, to obedience, or disobedience; and the indestructibility of the sentient being is necessary to the decrees of eternal justice. on your view, even in this life, just punishments for crimes would be almost impossible; for the materials of which human beings are composed change rapidly, and in a few years probably not an atom of the primitive structure remains yet even the materialist is obliged in old age to do penance for the sins of his youth, and does not complain of the injustice of his decrepit body, entirely changed and made stiff by time, suffering for the intemperance of his youthful flexible frame. on my idea, conscience is the frame of the mind, fitted for its probation in mortality. and this is in exact accordance with the foundations of our religion, the divine origin of which is marked no less by its history than its harmony with the principles of our nature. obedience to its precepts not only prepares for a better state of existence in another world, but is likewise calculated to make us happy here. we are constantly taught to renounce sensual pleasure and selfish gratifications, to forget our body and sensible organs, to associate our pleasures with mind, to fix our affections upon the great ideal generalisation of intelligence in the one supreme being. and that we are capable of forming to ourselves an imperfect idea even of the infinite mind is, i think, a strong presumption of our own immortality, and of the distinct relation which our finite knowledge bears to eternal wisdom. _phil_.--i am pleased with your views; they coincide with those i had formed at the time my imagination was employed upon the vision of the colosaeum, which i repeated to you, and are not in opposition with the opinions that the cool judgment and sound and humble faith of ambrosio have led me since to embrace. the doctrine of the materialists was always, even in my youth, a cold, heavy, dull, and insupportable doctrine to me, and necessarily tending to atheism. when i had heard, with disgust, in the dissecting-rooms the plan of the physiologist of the gradual accretion of matter, and its becoming endowed with irritability, ripening into sensibility and acquiring such organs as were necessary, by its own inherent forces, and at last rising into intellectual existence, a walk into the green fields or woods by the banks of rivers brought back my feelings from nature to god; i saw in all the powers of matter the instruments of the deity; the sunbeams, the breath of the zephyr, awakened animation in forms prepared by divine intelligence to receive it; the insensate seed, the slumbering egg, which were to be vivified, appeared like the new-born animal, works of a divine mind; i saw love as the creative principle in the material world, and this love only as a divine attribute. then, my own mind, i felt connected with new sensations and indefinite hopes, a thirst for immortality; the great names of other ages and of distant nations appeared to me to be still living around me; and, even in the funeral monuments of the heroic and the great, i saw, as it were, the decree of the indestructibility of mind. these feelings, though generally considered as poetical, yet, i think, offer a sound philosophical argument in favour of the immortality of the soul. in all the habits and instincts of young animals their feelings or movements may be traced in intimate relation to their improved perfect state; their sports have always affinities to their modes of hunting or catching their food, and young birds, even in the nest, show marks of fondness which, when their frames are developed, become signs of actions necessary to the reproduction and preservation of the species. the desire of glory, of honour, of immortal fame, and of constant knowledge, so usual in young persons of well-constituted minds, cannot, i think, be other than symptoms of the infinite and progressive nature of intellect--hopes which, as they cannot be gratified here, belong to a frame of mind suited to a nobler state of existence. _the unknown_.--religion, whether natural or revealed, has always the same beneficial influence on the mind. in youth, in health, and prosperity, it awakens feelings of gratitude and sublime love, and purifies at the same time that it exalts; but it is in misfortune, in sickness, in age, that its effects are most truly and beneficially felt; when submission in faith and humble trust in the divine will, from duties become pleasures, undecaying sources of consolation; then it creates powers which were believed to be extinct, and gives a freshness to the mind which was supposed to have passed away for ever, but which is now renovated as an immortal hope; then it is the pharos, guiding the wave- tost mariner to his home, as the calm and beautiful still basins or fiords, surrounded by tranquil groves and pastoral meadows, to the norwegian pilot escaping from a heavy storm in the north sea, or as the green and dewy spot gushing with fountains to the exhausted and thirsty traveller in the midst of the desert. its influence outlives all earthly enjoyments, and becomes stronger as the organs decay and the frame dissolves; it appears as that evening star of light in the horizon of life, which, we are sure, is to become in another season a morning star, and it throws its radiance through the gloom and shadow of death. dialogue the fifth. the chemical philosopher. i had been made religious by the conversations of ambrosio in italy; my faith was strengthened and exalted by the opinions of the unknown, for whom i had not merely that veneration awakened by exalted talents, but a strong affection founded upon the essential benefit of the preservation of my life owing to him. i ventured, the evening after our visit to the cave of adelsberg, to ask him some questions relating to his history and adventures. he said, "to attempt to give you any idea of the formation of my character would lead me into the history of my youth, which almost approaches to a tale of romance. the source of the little information and intelligence i possess i must refer to a restless activity of spirit, a love of glory which ever belonged to my infancy, and a sensibility easily excited and not easily conquered. my parentage was humble, yet i can believe a traditional history of my paternal grandmother, that the origin of our family was from an old norman stock; i found this belief upon certain feelings which i can only refer to an hereditary source, a pride of decorum, a tact and refinement even in boyhood, and which are contradictory to the idea of an origin from a race of peasants. accident opened to me in early youth a philosophical career, which i pursued with success. in manhood fortune smiled upon me and made me independent; i then really became a philosopher, and pursued my travels with the object of instructing myself and of benefiting mankind. i have seen most parts of europe, and conversed, i believe, with all the illustrious men of science belonging to them. my life has not been unlike that of the ancient greek sages. i have added some little to the quantity of human knowledge, and i have endeavoured to add something to the quantity of human happiness. in my early life i was a sceptic; i have informed you how i became a believer, and i constantly bless the supreme intelligence for the favour of some gleams of divine light which have been vouchsafed to me in this our state of darkness and doubt." _phil_.--i am surprised that with your powers you did not enter into a professional career either of law or politics; you would have gained the highest honours and distinctions. _the unknown_.--to me there never has been a higher source of honour or distinction than that connected with advances in science. i have not possessed enough of the eagle in my character to make a direct flight to the loftiest altitudes in the social world, and i certainly never endeavoured to reach those heights by using the creeping powers of the reptile who, in ascending, generally chooses the dirtiest path, because it is the easiest. _eub_.--i have often wondered that men of fortune and of rank do not apply themselves more to philosophical pursuits; they offer a delightful and enviable road to distinction, one founded upon the blessings and benefits conferred on our fellow-creatures; they do not supply the same sources of temporary popularity as successes in the senate or at the bar, but the glory resulting from them is permanent and independent of vulgar taste or caprice. in looking back to the history of the last five reigns in england, we find boyles, cavendishes, and howards, who rendered those great names more illustrious by their scientific honours; but we may in vain search the aristocracy now for philosophers, and there are very few persons who pursue science with true dignity; it is followed more as connected with objects of profit than those of fame, and there are fifty persons who take out patents for supposed inventions for one who makes a real discovery. _phil_.--the information we have already received from you proves to me that chemistry has been your favourite pursuit. i am surprised at this. the higher-mathematics and pure physics appear to me to offer much more noble objects of contemplation and fields of discovery, and, practically considered, the results of the chemist are much more humble, belonging principally to the apothecary's shop and the kitchen. _eub_.--i feel disposed to join you in attacking this favourite study of our friend, but merely to provoke him to defend it. i wish our attack would induce him to vindicate his science, and that we might enjoy a little of the sport of literary gladiators, at least, in order to call forth his skill and awaken his eloquence. _the unknown_.--i have no objection. let there be a fair discussion; remember we fight only with foils, and the point of mine shall be covered with velvet. in your attack upon chemistry, philalethes, you limited the use of it to the apothecary's shop and the kitchen. the first is an equivocal use; by introducing it into the kitchen you make it an art fundamental to all others. but if what you had stated had really meant to be serious, it would not have deserved a reply; as it is in mere playfulness, it shall not be thrown away. i want eloquence, however, to adorn my subject, yet it is sufficiently exciting even to awaken feeling. persons in general look at the magnificent fabric of civilized society as the result of the accumulated labour, ingenuity, and enterprise of man through a long course of ages, without attempting to define what has been owing to the different branches of human industry and science; and usually attribute to politicians, statesmen, and warriors a much greater share than really belongs to them in the work: what they have done is in reality little. the beginning of civilization is the discovery of some useful arts by which men acquire property, comforts, or luxuries. the necessity or desire of preserving them leads to laws and social institutions. the discovery of peculiar arts gives superiority to particular nations; and the love of power induces them to employ this superiority to subjugate other nations, who learn their arts, and ultimately adopt their manners; so that in reality the origin, as well as the progress and improvement, of civil society is founded in mechanical and chemical inventions. no people have ever arrived at any degree of perfection in their institutions who have not possessed in a high degree the useful and refined arts. the comparison of savage and civilized man, in fact, demonstrates the triumph of chemical and mechanical philosophy as the causes not only of the physical, but ultimately even of moral improvement. look at the condition of man in the lowest state in which we are acquainted with him. take the native of new holland, advanced only a few steps above the animal creation, and that principally by the use of fire; naked, defending himself against wild beasts or killing them for food only by weapons made of wood hardened in the fire, or pointed with stones or fish bones; living only in holes dug out of the earth, or in huts rudely constructed of a few branches of trees covered with grass; having no approach to the enjoyment of luxuries or even comforts; unable to provide for his most pressing wants; having a language scarcely articulate, relating only to the great objects of nature, or to his most pressing necessities or desires, and living solitary or in single families, unacquainted with religion, government, or laws, submitted to the mercy of nature or the elements. how different is man in his highest state of cultivation; every part of his body covered with the products of different chemical and mechanical arts made not only useful in protecting him from the inclemency of the seasons but combined in forms of beauty and variety; creating out of the dust of the earth from the clay under his feet instruments of use and ornament; extracting metals from the rude ore and giving to them a hundred different shapes for a thousand different purposes; selecting and improving the vegetable productions with which he covers the earth; not only subduing but taming and domesticating the wildest, the fleetest, and the strongest inhabitants of the wood, the mountain, and the air; making the winds carry him on every part of the immense ocean; and compelling the elements of air, water, and even fire as it were to labour for him; concentrating in small space materials which act as the thunderbolt, and directing their energies so as to destroy at immense distances; blasting the rock, removing the mountain, carrying water from the valley to the hill; perpetuating thought in imperishable words, rendering immortal the exertion of genius, and presenting them as common property to all awakening minds, becoming as it were the true image of divine intelligence receiving and bestowing the breath of life in the influence of civilization. _eub_.--really you are in the poetical, not the chemical chair, or rather on the tripod. we claim from you some accuracy of detail, some minute information, some proofs of what you assert. what you attribute to the chemical and mechanical arts, we might with the same propriety attribute to the fine arts, to letters, to political improvement, and to those inventions of which minerva and apollo and not vulcan are the patrons. _the unknown_.--i will be more minute. you will allow that the rendering skins insoluble in water by combining with them the astringent principle of certain vegetables is a chemical invention, and that without leather, our shoes, our carriages, our equipages would be very ill made; you will permit me to say, that the bleaching and dying of wool and silk, cotton, and flax, are chemical processes, and that the conversion of them into different clothes is a mechanical invention; that the working of iron, copper, tin, and lead, and the other metals, and the combining them in different alloys by which almost all the instruments necessary for the turner, the joiner, the stone-mason, the ship-builder, and the smith are made, are chemical inventions; even the press, to the influence of which i am disposed to attribute as much as you can do, could not have existed in any state of perfection without a metallic alloy; the combining of alkali and sand, and certain clays and flints together to form glass and porcelain is a chemical process; the colours which the artist employs to frame resemblances of natural objects, or to create combinations more beautiful than ever existed in nature, are derived from chemistry; in short, in every branch of the common and fine arts, in every department of human industry, the influence of this science is felt, and we may find in the fable of prometheus taking the flame from heaven to animate his man of clay an emblem of the effects of fire in its application to chemical purposes in creating the activity and almost the life of civil society. _phil_.--it appears to me that you attribute to science what in many cases has been the result of accident. the processes of most of the useful arts, which you call chemical, have been invented and improved without any refined views, without any general system of knowledge. lucretius attributes to accident the discovery of the fusion of the metals; a person in touching a shell-fish observes that it emits a purple liquid as a dye, hence the tyrian purple; clay is observed to harden in the fire, and hence the invention of bricks, which could hardly fail ultimately to lead to the discovery of porcelain; oven glass, the most perfect and beautiful of those manufactures you call chemical, is said to have been discovered by accident; theophrastus states that some merchants who were cooking on lumps of soda or natron, near the mouth of the river belus, observed that a hard and vitreous substance was formed where the fused natron ran into the sand. _the unknown_.--i will readily allow that accident has had much to do with the origin of the arts as with the progress of the sciences. but it has been by scientific processes and experiments that these accidental results have been rendered really applicable to the purposes of common life. besides, it requires a certain degree of knowledge and scientific combination to understand and seize upon the facts which have originated in accident. it is certain that in all fires alkaline substances and sand are fused together, and clay hardened; yet for ages after this discovery of fire, glass and porcelain were unknown till some men of genius profited by scientific combination often observed but never applied. it suits the indolence of those minds which never attempt anything, and which probably if they did attempt anything would not succeed, to refer to accident that which belongs to genius. it is sometimes said by such persons, that the discovery of the law of gravitation was owing to accident: and a ridiculous story is told of the falling of an apple as the cause of this discovery. as well might the invention of fluxions or the architectural wonders of the dome of st. peter's, or the miracles of art the st. john of raphael or the apollo belvidere, be supposed to be owing to accidental combinations. in the progress of an art, from its rudest to its more perfect state, the whole process depends upon experiments. science is in fact nothing more than the refinement of common sense making use of facts already known to acquire new facts. clays which are yellow are known to burn red; calcareous earth renders flint fusible--the persons who have improved earthenware made their selections accordingly. iron was discovered at least one thousand years before it was rendered malleable; and from what herodotus says of this discovery, there can be little doubt that it was developed by a scientific worker in metals. vitruvius tells us that the ceruleum, a colour made of copper, which exists in perfection in all the old paintings of the greeks and romans and on the mummies of the egyptians, was discovered by an egyptian king; there is therefore every reason to believe that it was not the result of accidental combination, but of experiments made for producing or improving colours. amongst the ancient philosophers, many discoveries are attributed to democritus and anaxagoras; and, connected with chemical arts, the narrative of the inventions of archimedes alone, by plutarch, would seem to show how great is the effect of science in creating power. in modern times, the refining of sugar, the preparation of nitre, the manufacturing of acids, salts, &c., are all results of pure chemistry. take gunpowder as a specimen; no person but a man infinitely diversifying his processes and guided by analogy could have made such a discovery. look into the books of the alchemists, and some idea may be formed of the effects of experiments. it is true, these persons were guided by false views, yet they made most useful researches; and lord bacon has justly compared them to the husbandman who, searching for an imaginary treasure, fertilised the soil. they might likewise be compared to persons who, looking for gold, discover the fragments of beautiful statues, which separately are of no value, and which appear of little value to the persons who found them; but which, when selected and put together by artists and their defective parts supplied, are found to be wonderfully perfect and worthy of conservation. look to the progress of the arts since they have been enlightened by a system of science, and observe with what rapidity they have advanced. again, the steam-engine in its rudest form was the result of a chemical experiment; in its refined state it required the combinations of all the most recondite principles of chemistry and mechanics, and that excellent philosopher who has given this wonderful instrument of power to civil society was led to the great improvements he made by the discoveries of a kindred genius on the heat absorbed when water becomes steam, and of the heat evolved when steam becomes water. even the most superficial observer must allow in this case a triumph of science, for what a wonderful impulse has this invention given to the progress of the arts and manufactories in our country, how much has it diminished labour, how much has it increased the real strength of the country! acting as it were with a thousand hands, it has multiplied our active population; and receiving its elements of activity from the bowels of the earth, it performs operations which formerly were painful, oppressive, and unhealthy to the labourers, with regularity and constancy, and gives security and precision to the efforts of the manufacturer. and the inventions connected with the steam-engine, at the same time that they have greatly diminished labour of body, have tended to increase power of mind and intellectual resources. adam smith well observes that manufacturers are always more ingenious than husbandmen; and manufacturers who use machinery will probably always be found more ingenious than handicraft manufacturers. you spoke of porcelain as a result of accident; the improvements invented in this country, as well as those made in germany and france, have been entirely the result of chemical experiments; the dresden and the sevres manufactories have been the work of men of science, and it was by multiplying his chemical researches that wedgewood was enabled to produce at so cheap a rate those beautiful imitations which while they surpass the ancient vases in solidity and perfection of material, equal them in elegance, variety, and tasteful arrangement of their forms. in another department, the use of the electrical conductor was a pure scientific combination, and the sublimity of the discovery of the american philosopher was only equalled by the happy application he immediately made of it. in our own times it would be easy to point out numerous instances in which great improvements and beneficial results connected with the comforts, the happiness, and even life of our fellow creatures have been the results of scientific combinations; but i cannot do this without constituting myself a judge of the works of philosophers who are still alive, whose researches are known, whose labours are respected, and who will receive from posterity praises that their contemporaries hardly dare to bestow upon them. _eub_.--we will allow that you have shown in many cases the utility of scientific investigation as connected with the progress of the useful arts. but, in general, both the principles of chemistry are followed, and series of experiments performed without any view to utility; and a great noise is made if a new metal or a new substance is discovered, or if some abstracted law is made known relating to the phenomena of nature; yet, amongst the variety of new substances, few have been applied to any trifling use even, and the greater number have had no application at all. and with respect to the general views of the science, it would be difficult to show that any real good had resulted from the discovery or extension of them. it does not add much to the dignity of a pursuit that those persons who have followed it for profit have really been most useful, and that the mere artisan or chemical manufacturer has done more for society than the chemical philosopher. besides, it has always appeared to me that it is in the nature of this science to encourage mediocrity and to attach importance to insignificant things; very slight chemical labours seem to give persons a claim to the title of philosopher--to have dissolved a few grains of chalk in an acid, to have shown that a very useless stone contains certain known ingredients, or that the colouring matter of a flower is soluble in acid and not in alkali, is thought by some a foundation for chemical celebrity. i once began to attend a course of chemical lectures and to read the journals containing the ephemeral productions of this science; i was dissatisfied with the nature of the evidence which the professor adopted in his demonstrations, and disgusted with the series of observations and experiments which were brought forward one month to be overturned the next. in november there was a zingeberic acid, which in january was shown to have no existence; one year there was a vegetable acid, which the next was shown to be the same as an acid known thirty years ago; to- day a man was celebrated for having discovered a new metal or a new alkali, and they flourished like the scenes in a new pantomime only to disappear. then, the great object of the hundred triflers in the science appeared to be to destroy the reputation of the three or four great men whose labours were really useful, and had in them something of dignity. and, there not being enough of trifling results or false experiments to fill up the pages of the monthly journals, the deficiency was supplied by some crude theories or speculations of unknown persons, or by some ill- judged censure or partial praise of the editor. _the unknown_.--i deny _in toto_ the accuracy of what you are advancing. i have already shown that real philosophers, not labouring for profit, have done much by their own inventions for the useful arts; and, amongst the new substances discovered, many have had immediate and very important applications. the chlorine, or oxymuriatic gas of scheele, was scarcely known before it was applied by berthollet to bleaching; scarcely was muriatic acid gas discovered by priestley, when guyton de morveau used it for destroying contagion. consider the varied and diversified applications of platinum, which has owed its existence as a useful metal entirely to the labours of an illustrious chemical philosopher; look at the beautiful yellow afforded by one of the new metals, chrome; consider the medical effects of iodine in some of the most painful and disgusting maladies belonging to human nature, and remember how short a time investigations have been made for applying the new substances. besides, the mechanical or chemical manufacturer has rarely discovered anything; he has merely applied what the philosopher has made known, he has merely worked upon the materials furnished to him. we have no history of the manner in which iron was rendered malleable; but we know that platinum could only have been worked by a person of the most refined chemical resources, who made multiplied experiments upon it after the most ingenious and profound views. but, waiving all common utility, all vulgar applications, there is something in knowing and understanding the operation of nature, some pleasure in contemplating the order and harmony of the arrangements belonging to the terrestrial system of things. there is no absolute utility in poetry, but it gives pleasure, refines and exalts the mind. philosophic pursuits have likewise a noble and independent use of this kind, and there is a double reason offered for pursuing them, for whilst in their sublime speculations they reach to the heavens, in their application they belong to the earth; whilst they exalt the intellect, they provide food for our common wants, and likewise minister to the noblest appetites and most exalted views belonging to our nature. the results of this science are not like the temples of the ancients, in which statues of the gods were placed, where incense was offered and sacrifices were performed, and which were presented to the adoration of the multitude founded upon superstitious feelings; but they are rather like the palaces of the moderns, to be admired and used, and where the statues, which in the ancients raised feelings of adoration and awe, now produce only feelings of pleasure, and gratify a refined taste. it is surely a pure delight to know how and by what processes this earth is clothed with verdure and life, how the clouds, mists, and rain are formed, what causes all the changes of this terrestrial system of things, and by what divine laws order is preserved amidst apparent confusion. it is a sublime occupation to investigate the cause of the tempest and the volcano, and to point out their use in the economy of things, to bring the lightning from the clouds and make it subservient to our experiments, to produce, as it were, a microcosm in the laboratory of art, and to measure and weigh those invisible atoms which, by their motions and changes according to laws impressed upon them by the divine intelligence, constitute the universe of things. the true chemical philosopher sees good in all the diversified forms of the external world. whilst he investigates the operations of infinite power guided by infinite wisdom, all low prejudices, all mean superstitions, disappear from his mind. he sees man an atom amidst atoms fixed upon a point in space, and yet modifying the laws that are around him by understanding them, and gaining, as it were, a kind of dominion over time and an empire in material space, and exerting on a scale infinitely small a power seeming a sort of shadow or reflection of a creative energy, and which entitles him to the distinction of being made in the image of god and animated by a spark of the divine mind. whilst chemical pursuits exalt the understanding, they do not depress the imagination or weaken genuine feeling; whilst they give the mind habits of accuracy by obliging it to attend to facts, they likewise extend its analogies, and though conversant with the minute forms of things, they have for their ultimate end the great and magnificent objects of nature. they regard the formation of a crystal, the structure of a pebble, the nature of a clay or earth; and they apply to the causes of the diversity of our mountain chains, the appearances of the winds, thunderstorms, meteors, the earthquake, the volcano, and all those phenomena which offer the most striking images to the poet and the painter. they keep alive that inextinguishable thirst after knowledge which is one of the greatest characteristics of our nature, for every discovery opens a new field for investigation of facts, shows us the imperfection of our theories. it has justly been said that the greater the circle of light, the greater the boundary of darkness by which it is surrounded. this strictly applies to chemical inquiries, and hence they are wonderfully suited to the progressive nature of the human intellect, which by its increasing efforts to acquire a higher kind of wisdom, and a state in which truth is fully and brightly revealed, seems, as it were, to demonstrate its birthright to immortality. _eub_.--i am glad that our opposition has led you to so complete a vindication of your favourite science. i want no further proof of its utility. i regret that i have not before made it a particular object of study. _phil_.--as our friend has so fully convinced us of the importance of chemistry, i hope he will descend to some particulars as to its real nature, its objects, its instruments. i would willingly have a definition of chemistry and some idea of the qualifications necessary to become a chemist, and of the apparatus essential for understanding what has been already done in the science, and for pursuing new inquiries. _the unknown_.--there is nothing more difficult than a good definition, for it is scarcely possible to express in a few words the abstracted view of an infinite variety of facts. dr. black has defined chemistry to be that science which treats of the changes produced in bodies by motions of their ultimate particles or atoms, but this definition is hypothetical, for the ultimate particles or atoms are mere creations of the imagination. i will give you a definition, which will have the merit of novelty and which is probably general in its application. chemistry relates to those operations by which the intimate nature of bodies is changed, or by which they acquire new properties. this definition will not only apply to the effects of mixture, but to the phenomena of electricity, and, in short, to all the changes which do not merely depend upon the motion or division of masses of matter. however difficult it may have been to have given you a definition of chemistry, it is still more difficult to give you a detail of all the qualities necessary for a chemical philosopher. i will not name as many as athenaeus has named for a cook, who, he says, ought to be a mathematician, a theoretical musician, a natural philosopher, a natural historian, &c., though you had a disposition just now to make chemistry merely subservient to the uses of the kitchen. but i will seriously mention some of the studies fundamental to the higher departments of this science; a man may be a good practical chemist perhaps without possessing them, but he never can become a great chemical philosopher. the person who wishes to understand the higher departments of chemistry, or to pursue them in their most interesting relations to the economy of nature, ought to be well-grounded in elementary mathematics; he will oftener have to refer to arithmetic than algebra, and to algebra than to geometry. but all these sciences lend their aid to chemistry; arithmetic, in determining the proportions of analytical results and the relative weights of the elements of bodies; algebra, in ascertaining the laws of the pressure of elastic fluids, the force of vapour as dependent upon temperature, and the effects of masses and surfaces on the communication and radiation of heat; the applications of geometry are principally limited to the determination of the crystalline forms of bodies, which constitute the most important type of their nature, and often offer useful hints for analytical researches respecting their composition. the first principles of natural philosophy or general physics ought not to be entirely unknown to the chemist. as the most active agents are fluids, elastic fluids, heat, light, and electricity, he ought to have a general knowledge of mechanics, hydrodynamics, pneumatics, optics, and electricity. latin and greek among the dead and french among the modern languages are necessary, and, as the most important after french, german and italian. in natural history and in literature what belongs to a liberal education, such as that of our universities, is all that is required; indeed, a young man who has performed the ordinary course of college studies which are supposed fitted for common life and for refined society, has all the preliminary knowledge necessary to commence the study of chemistry. the apparatus essential to the modern chemical philosopher is much less bulky and expensive than that used by the ancients. an air pump, an electrical machine, a voltaic battery (all of which may be upon a small scale), a blow-pipe apparatus, a bellows and forge, a mercurial and water-gas apparatus, cups and basins of platinum and glass, and the common reagents of chemistry, are what are required. all the implements absolutely necessary may be carried in a small trunk, and some of the best and most refined researches of modern chemists have been made by means of an apparatus which might with ease be contained in a small travelling carriage, and the expense of which is only a few pounds. the facility with which chemical inquiries are carried on, and the simplicity of the apparatus, offer additional reasons, to those i have already given, for the pursuit of this science. it is not injurious to the health; the modern chemist is not like the ancient one, who passed the greater part of his time exposed to the heat and smoke of a furnace and the unwholesome vapours of acids and alkalies and other menstrua, of which, for a single experiment, he consumed several pounds. his processes may be carried on in the drawing-room, and some of them are no less beautiful in appearance than satisfactory in their results. it was said, by an author belonging to the last century, of alchemy, "that its beginning was deceit, its progress labour, and its end beggary." it may be said of modern chemistry, that its beginning is pleasure, its progress knowledge, and its objects truth and utility. i have spoken of the scientific attainments necessary for the chemical philosopher; i will say a few words of the intellectual qualities necessary for discovery or for the advancement of the science. amongst them patience, industry, and neatness in manipulation, and accuracy and minuteness in observing and registering the phenomena which occur, are essential. a steady hand and a quick eye are most useful auxiliaries; but there have been very few great chemists who have preserved these advantages through life; for the business of the laboratory is often a service of danger, and the elements, like the refractory spirits of romance, though the obedient slave of the magician, yet sometimes escape the influence of his talisman and endanger his person. both the hands and eyes of others, however, may be sometimes advantageously made use of. by often repeating a process or an observation, the errors connected with hasty operations or imperfect views are annihilated; and, provided the assistant has no preconceived notions of his own, and is ignorant of the object of his employer in making the experiment, his simple and bare detail of facts will often be the best foundation for an opinion. with respect to the higher qualities of intellect necessary for understanding and developing the general laws of the science, the same talents i believe are required as for making advancement in every other department of human knowledge; i need not be very minute. the imagination must be active and brilliant in seeking analogies; yet entirely under the influence of the judgment in applying them. the memory must be extensive and profound; rather, however, calling up general views of things than minute trains of thought. the mind must not be, like an encyclopedia, a burthen of knowledge, but rather a critical dictionary which abounds in generalities, and points out where more minute information may be obtained. in detailing the results of experiments and in giving them to the world, the chemical philosopher should adopt the simplest style and manner; he will avoid all ornaments as something injurious to his subject, and should bear in mind the saying of the first king of great britain respecting a sermon which was excellent in doctrine but overcharged with poetical allusions and figurative language, "that the tropes and metaphors of the speaker were like the brilliant wild flowers in a field of corn--very pretty, but which did very much hurt the corn." in announcing even the greatest and most important discoveries, the true philosopher will communicate his details with modesty and reserve; he will rather be a useful servant of the public, bringing forth a light from under his cloak when it is needed in darkness, than a charlatan exhibiting fireworks and having a trumpeter to announce their magnificence. i see you are smiling, and think what i am saying in bad taste; yet, notwithstanding, i will provoke your smiles still further by saying a word or two on his other moral qualities. that he should be humble-minded, you will readily allow, and a diligent searcher after truth, and neither diverted from this great object by the love of transient glory or temporary popularity, looking rather to the opinion of ages than to that of a day, and seeking to be remembered and named rather in the epochas of historians than in the columns of newspaper writers or journalists. he should resemble the modern geometricians in the greatness of his views and the profoundness of his researches, and the ancient alchemists in industry and piety. i do not mean that he should affix written prayers and inscriptions of recommendations of his processes to providence, as was the custom of peter wolfe, and who was alive in my early days, but his mind should always be awake to devotional feeling, and in contemplating the variety and the beauty of the external world, and developing its scientific wonders, he will always refer to that infinite wisdom through whose beneficence he is permitted to enjoy knowledge; and, in becoming wiser, he will become better, he will rise at once in the scale of intellectual and moral existence, his increased sagacity will be subservient to a more exalted faith, and in proportion as the veil becomes thinner through which he sees the causes of things he will admire more the brightness of the divine light by which they are rendered visible. dialogue the sixth. pola, or time. during our stay in illyria, i made an excursion by water with the unknown, my preserver, now become my friend, and eubathes, to pola, in istria. we entered the harbour of pola in a felucca when the sun was setting; and i know no scene more splendid than the amphitheatre seen from the sea in this light. it appears not as a building in ruins, but like a newly erected work, and the reflection of the colours of its brilliant marble and beautiful forms seen upon the calm surface of the waters gave to it a double effect--that of a glorious production of art and of a magnificent picture. we examined with pleasure the remains of the arch of augustus and the temple, very perfect monuments of imperial grandeur. but the splendid exterior of the amphitheatre was not in harmony with the bare and naked walls of the interior; there were none of those durable and grand seats of marble, such as adorn the amphitheatre of verona, from which it is probable that the whole of the arena and conveniences for the spectators had been constructed of wood. their total disappearance led us to reflect upon the causes of the destruction of so many of the works of the older nations. i said, in our metaphysical abstractions, we refer the changes, the destruction of material forms, to time, but there must be physical laws in nature by which they are produced; and i begged our new friend to give us some ideas on this subject in his character of chemical philosopher. if human science, i said, has discovered the principle of the decay of things, it is possible that human art may supply means of conservation, and bestow immortality on some of the works which appear destined by their perfection for future ages. _the unknown_.--i shall willingly communicate to you my views of the operation of time, philosophically considered. a great philosopher has said, man can in no other way command nature but in obeying her laws; and, in these laws, the principle of change is a principle of life; without decay, there can be no reproduction; and everything belonging to the earth, whether in its primitive state, or modified by human hands, is submitted to certain and immutable laws of destruction, as permanent and universal as those which produce the planetary motions. the property which, as far as our experience extends, universally belongs to matter, gravitation, is the first and most general cause of change in our terrestrial system; and, whilst it preserves the great mass of the globe in a uniform state, its influence is continually producing alterations upon the surface. the water, raised in vapour by the solar heat, is precipitated by the cool air in the atmosphere; it is carried down by gravitation to the surface, and gains its mechanical force from this law. whatever is elevated above the superfices by the powers of vegetation or animal life, or by the efforts of man, by gravitation constantly tends to the common centre of attraction; and the great reason of the duration of the pyramid above all other forms is, that it is most fitted to resist the force of gravitation. the arch, the pillar, and all perpendicular constructions, are liable to fall when a degradation from chemical or mechanical causes takes place in their inferior parts. the forms upon the surface of the globe are preserved from the influence of gravitation by the attraction of cohesion, or by chemical attraction; but if their parts had freedom of motion, they would all be levelled by this power, gravitation, and the globe would appear as a plane and smooth oblate spheroid, flattened at the poles. the attraction of cohesion or chemical attraction, in its most energetic state, is not liable to be destroyed by gravitation; this power only assists the agencies of other causes of degradation. attraction, of whatever kind, tends, as it were, to produce rest--a sort of eternal sleep in nature. the great antagonist power is heat. by the influence of the sun the globe is exposed to great varieties of temperature; an addition of heat expands bodies, and an abstraction of heat causes them to contract; by variation of heat, certain kinds of matter are rendered fluid, or elastic, and changes from fluids into solids, or from solids or fluids into elastic substances, and _vice versa_, are produced; and all these phenomena are connected with alterations tending to the decay or destruction of bodies. it is not probable that the mere contraction or expansion of a solid, from the subtraction or addition of heat, tends to loosen its parts; but if water exists in these parts, then its expansion, either in becoming vapour or ice, tends not only to diminish their cohesion, but to break them into fragments. there is, you know, a very remarkable property of water--its expansion by cooling, and at the time of becoming ice--and this is a great cause of destruction in the northern climates; for where ice forms in the crevices or cavities of stones, or when water which has penetrated into cement freezes, its expansion acts with the force of the lever or the screw in destroying or separating the parts of bodies. the mechanical powers of water, as rain, hail, or snow, in descending from the atmosphere, are not entirely without effect; for in acting upon the projections of solids, drops of water or particles of snow, and still more of hail, have a power of abrasion, and a very soft substance, from its mass assisting gravitation, may break a much harder one. the glacier, by its motion, grinds into powder the surface of the granite rock; and the alpine torrents, that have their origin under glaciers, are always turbid, from the destruction of the rocks on which the glacier is formed. the effect of a torrent in deepening its bed will explain the mechanical agency of fluid-water, though this effect is infinitely increased, and sometimes almost entirely dependent, upon the solid matters which are carried down by it. an angular fragment of stone in the course of ages moved in the cavity of a rock makes a deep round excavation, and is worn itself into a spherical form. a torrent of rain flowing down the side of a building carries with it the silicious dust, or sand, or matter which the wind has deposited there, and acts upon a scale infinitely more minute, but according to the same law. the buildings of ancient rome have not only been liable to the constant operation of the rain-courses, or minute torrents produced by rains, but even the tiber, swollen with floods of the sabine mountains and the apennines, has often entered into the city, and a winter seldom passes away in which the area of the pantheon has not been filled with water, and the reflection of the cupola seen in a smooth lake below. the monuments of egypt are perhaps the most ancient and permanent of those belonging to the earth, and in that country rain is almost unknown. and all the causes of degradation connected with the agency of water act more in the temperate climates than in the hot ones, and most of all in those countries where the inequalities of temperature are greatest. the mechanical effects of air are principally in the action of winds in assisting the operation of gravitation, and in abrading by dust, sand, stones, and atmospheric water. these effects, unless it be in the case of a building blown down by a tempest, are imperceptible in days, or even years; yet a gentle current of air carrying the silicious sand of the desert, or the dust of a road for ages against the face of a structure, must ultimately tend to injure it, for with infinite or unlimited duration, an extremely small cause will produce a very great effect. the mechanical agency of electricity is very limited; the effects of lightning have, however, been witnessed, even in some of the great monuments of antiquity, the colosaeum at rome, for instance; and only last year, in a violent thunderstorm, some of the marble, i have been informed, was struck from the top of one of the arches in this building, and a perpendicular rent made, of some feet in diameter. but the chemical effects of electricity, though excessively slow and gradual, yet are much more efficient in the great work of destruction. it is to the general chemical doctrines of the changes produced by this powerful agent that i must now direct your especial attention. _eub_.--would not the consideration of the subject have been more distinct, and your explanations of the phenomena more simple, had you commenced by dividing the causes of change into mechanical and chemical; if you had first considered them separately, and then their joint effects? _the unknown_.--the order i have adopted is not very remote from this. but i was perhaps wrong in treating first of the agency of gravitation, which owes almost all its powers to the operation of other causes. in consequence of your hint, i shall alter my plan a little, and consider first the chemical agency of water, then that of air, and lastly that of electricity. in every species of chemical change, temperature is concerned. but unless the results of volcanoes and earthquakes be directly referred to this power, it has no chemical effect in relation to the changes ascribed to time simply considered as heat, but its operations, which are the most important belonging to the terrestrial cycle of changes, are blended with, or bring into activity, those of other agents. one of the most distinct and destructive agencies of water depends upon its solvent powers, which are usually greatest when its temperature is highest. water is capable of dissolving, in larger or smaller proportions, most compound bodies, and the calcareous and alkaline elements of stones are particularly liable to this kind of operation. when water holds in solution carbonic acid, which is always the case when it is precipitated from the atmosphere, its power of dissolving carbonate of lime is very much increased, and in the neighbourhood of great cities, where the atmosphere contains a large proportion of this principle, the solvent powers of rain upon the marble exposed to it must be greatest. whoever examines the marble statues in the british museum, which have been removed from the exterior of the parthenon, will be convinced that they have suffered from this agency; and an effect distinct in the pure atmosphere and temperate climate of athens, must be upon a higher scale in the vicinity of other great european cities, where the consumption of fuel produces carbonic acid in large quantities. metallic substances, such as iron, copper, bronze, brass, tin, and lead, whether they exist in stones, or are used for support or connection in buildings, are liable to be corroded by water holding in solution the principles of the atmosphere; and the rust and corrosion, which are made, poetically, qualities of time, depend upon the oxidating powers of water, which by supplying oxygen in a dissolved or condensed state enables the metals to form new combinations. all the vegetable substances, exposed to water and air, are liable to decay, and even the vapour in the air, attracted by wood, gradually reacts upon its fibres and assists decomposition, or enables its elements to take new arrangements. hence it is that none of the roofs of ancient buildings more than a thousand years old remain, unless it be such as are constructed of stone, as those of the pantheon of rome and the tomb of theodoric at ravenna, the cupola of which is composed of a single block of marble. the pictures of the greek masters, which were painted on the wood of the abies, or pine of the mediterranean, likewise, as we are informed by pliny, owed their destruction not to a change in the colours, not to the alteration of the calcareous ground on which they were painted, but to the decay of the tablets of wood on which the intonaco or stucco was laid. amongst the substances employed in building, wood, iron, tin, and lead, are most liable to decay from the operation of water, then marble, when exposed to its influence in the fluid form; brass, copper, granite, sienite, and porphyry are more durable. but in stones, much depends upon the peculiar nature of their constituent parts; when the feldspar of the granite rocks contains little alkali or calcareous earth, it is a very permanent stone; but, when in granite, porphyry, or sienite, either the feldspar contains much alkaline matter, or the mica, schorl, or hornblende much protoxide of iron, the action of water containing oxygen and carbonic acid on the ferruginous elements tends to produce the disintegration of the stone. the red granite, black sienite, and red porphyry of egypt, which are seen at rome in obelisks, columns, and sarcophagi, are amongst the most durable compound stones; but the grey granites of corsica and elba are extremely liable to undergo alteration: the feldspar contains much alkaline matter; and the mica and schorl, much protoxide of iron. a remarkable instance of the decay of granite may be seen in the hanging tower of pisa; whilst the marble pillars in the basement remain scarcely altered, the granite ones have lost a considerable portion of their surface, which falls off continually in scales, and exhibits everywhere stains from the formation of peroxide of iron. the kaolin, or clay, used in most countries for the manufacture of fine porcelain or china, is generally produced from the feldspar of decomposing granite, in which the cause of decay is the dissolution and separation of the alkaline ingredients. _eub_.--i have seen serpentines, basalts, and lavas which internally were dark, and which from their weight, i should suppose, must contain oxide of iron, superficially brown or red, and decomposing. undoubtedly this was from the action of water impregnated with air upon their ferruginous elements. _the unknown_.--you are perfectly right. there are few compound stones, possessing a considerable specific gravity, which are not liable to change from this cause; and oxide of iron amongst the metallic substances anciently known, is the most generally diffused in nature, and most concerned in the changes which take place on the surface of the globe. the chemical action of carbonic acid is so much connected with that of water, that it is scarcely possible to speak of them separately, as must be evident from what i have before said; but the same action which is exerted by the acid dissolved in water is likewise exerted by it in its elastic state, and in this case the facility with which the quantity is changed makes up for the difference of the degree of condensation. there is no reason to believe that the azote of the atmosphere has any considerable action in producing changes of the nature we are studying on the surface; the aqueous vapour, the oxygen and the carbonic acid gas, are, however, constantly in combined activity, and above all the oxygen. and, whilst water, uniting its effects with those of carbonic acid, tends to disintegrate the parts of stones, the oxygen acts upon vegetable matter. and this great chemical agent is at once necessary, in all the processes of life and in all those of decay, in which nature, as it were, takes again to herself those instruments, organs, and powers, which had for a while been borrowed and employed for the purpose or the wants of the living principle. almost everything effected by rapid combinations in combustion may also be effected gradually by the slow absorption of oxygen; and though the productions of the animal and vegetable kingdom are much more submitted to the power of atmospheric agents than those of the mineral kingdom, yet, as in the instances which have just been mentioned, oxygen gradually destroys the equilibrium of the elements of stones, and tends to reduce into powder, to render fit for soils, even the hardest aggregates belonging to our globe. electricity, as a chemical agent, may be considered not only as directly producing an infinite variety of changes, but likewise as influencing almost all which take place. there are not two substances on the surface of the globe that are not in different electrical relations to each other; and chemical attraction itself seems to be a peculiar form of the exhibition of electrical attraction; and wherever the atmosphere, or water, or any part of the surface of the earth gains accumulated electricity of a different kind from the contiguous surfaces, the tendency of this electricity is to produce new arrangements of the parts of these surfaces; thus a positively electrified cloud, acting even at a great distance on a moistened stone, tends to attract its oxygenous, or acidiform or acid, ingredients, and a negatively electrified cloud has the same effect upon its earthy, alkaline, or metallic matter. and the silent and slow operation of electricity is much more important in the economy of nature than its grand and impressive operation in lightning and thunder. the chemical agencies of water and air are assisted by those of electricity; and their joint effects combined with those of gravitation and the mechanical ones i first described are sufficient to account for the results of time. but the physical powers of nature in producing decay are assisted likewise by certain agencies or energies of organised beings. a polished surface of a building or a statue is no sooner made rough from the causes that have been mentioned than the seeds of lichens and mosses, which are constantly floating in our atmosphere, make it a place of repose, grow, and increase, and from their death, their decay, and decomposition carbonaceous matter is produced, and at length a soil is formed, in which grass can fix its roots. in the crevices of walls, where this soil is washed down, even the seeds of trees grow, and, gradually as a building becomes more ruined, ivy and other parasitical plants cover it. even the animal creation lends its aid in the process of destruction when man no longer labours for the conservation of his works. the fox burrows amongst ruins, bats and birds nestle in the cavities in walls, the snake and the lizard likewise make them their habitation. insects act upon a smaller scale, but by their united energies sometimes produce great effect; the ant, by establishing her colony and forming her magazines, often saps the foundations of the strongest buildings, and the most insignificant creatures triumph, as it were, over the grandest works of man. add to these sure and slow operations the devastations of war, the effects of the destructive zeal of bigotry, the predatory fury of barbarians seeking for concealed wealth under the foundations of buildings, and tearing from them every metallic substance, and it is rather to be wondered that any of the works of the great nations of antiquity are still in existence. _phil_.--your view of the causes of devastation really is a melancholy one. nor do i see any remedy; the most important causes will always operate. yet, supposing the constant existence of a highly civilised people, the ravages of time might be repaired, and by defending the finest works of art from the external atmosphere, their changes would be scarcely perceptible. _eub_.--i doubt much whether it is for the interests of a people that its public works should be of a durable kind. one of the great causes of the decline of the roman empire was that the people of the republic and of the first empire left nothing for their posterity to do; aqueducts, temples, forums, everything was supplied, and there were no objects to awaken activity, no necessity to stimulate their inventive faculties, and hardly any wants to call forth their industry. _the unknown_.--at least, you must allow the importance of preserving objects of the fine arts. almost everything we have worthy of admiration is owing to what has been preserved from the greek school, and the nations who have not possessed these works or models have made little or no progress towards perfection. nor does it seem that a mere imitation of nature is sufficient to produce the beautiful or perfect; but the climate, the manners, customs, and dress of the people, its genius and taste, all co-operate. such principles of conservation as philalethes has referred to are obvious. no works of excellence ought to be exposed to the atmosphere, and it is a great object to preserve them in apartments of equable temperature and extremely dry. the roofs of magnificent buildings should be of materials not likely to be dissolved by water or changed by air. many electrical conductors should be placed so as to prevent the slow or the rapid effects of atmospheric electricity. in painting, lapis lazuli or coloured hard glasses, in which the oxides are not liable to change, should be used, and should be laid on marble or stucco encased in stone, and no animal or vegetable substances, except pure carbonaceous matter, should be used in the pigments, and none should be mixed with the varnishes. _eub_.--yet, when all is done that can be done in the work of conservation, it is only producing a difference in the degree of duration. and from the statements that our friend has made it is evident that none of the works of a mortal being can be eternal, as none of the combinations of a limited intellect can be infinite. the operations of nature, when slow, are no less sure; however man may for a time usurp dominion over her, she is certain of recovering her empire. he converts her rocks, her stones, her trees, into forms of palaces, houses, and ships; he employs the metals found in the bosom of the earth as instruments of power, and the sands and clays which constitute its surface as ornaments and resources of luxury; he imprisons air by water, and tortures water by fire to change or modify or destroy the natural forms of things. but, in some lustrums his works begin to change, and in a few centuries they decay and are in ruins; and his mighty temples, framed as it were for immortal and divine purposes, and his bridges formed of granite and ribbed with iron, and his walls for defence, and the splendid monuments by which he has endeavoured to give eternity even to his perishable remains, are gradually destroyed; and these structures, which have resisted the waves of the ocean, the tempests of the sky, and the stroke of the lightning, shall yield to the operation of the dews of heaven, of frost, rain, vapour, and imperceptible atmospheric influences; and, as the worm devours the lineaments of his mortal beauty, so the lichens and the moss and the most insignificant plants shall feed upon his columns and his pyramids, and the most humble and insignificant insects shall undermine and sap the foundations of his colossal works, and make their habitations amongst the ruins of his palaces and the falling seats of his earthly glory. _phil_.--your history of the laws of the inevitable destruction of material forms recalls to my memory our discussion at adelsberg. the changes of the material universe are in harmony with those which belong to the human body, and which you suppose to be the frame or machinery of the sentient principle. may we not venture to imagine that the visible and tangible world, with which we are acquainted by our sensations, bears the same relation to the divine and infinite intelligence that our organs bear to our mind, with this only difference, that in the changes of the divine system there is no decay, there being in the order of things a perfect unity, and all the powers springing from one will and being a consequence of that will, are perfectly and unalterably balanced. newton seemed to apprehend, that in the laws of the planetary motions there was a principle which would ultimately be the cause of the destruction of the system. laplace, by pursuing and refining the principles of our great philosopher, has proved that what appeared sources of disorder are, in fact, the perfecting machinery of the system, and that the principle of conservation is as eternal as that of motion. _the unknown_.--i dare not offer any speculations on this grand and awful subject. we can hardly comprehend the cause of a simple atmospheric phenomenon, such as the fall of a heavy body from a meteor; we cannot even embrace in one view the millionth part of the objects surrounding us, and yet we have the presumption to reason upon the infinite universe and the eternal mind by which it was created and is governed. on these subjects i have no confidence in reason, i trust only to faith; and, as far as we ought to inquire, we have no other guide but revelation. _phil_.--i agree with you that whenever we attempt metaphysical speculations, we must begin with a foundation of faith. and being sure from revelation that god is omnipotent and omnipresent, it appears to me no improper use of our faculties to trace even in the natural universe the acts of his power and the results of his wisdom, and to draw parallels from the infinite to the finite mind. remember, we are taught that man was created in the image of god, and, i think, it cannot be doubted that in the progress of society man has been made a great instrument by his energies and labours for improving the moral universe. compare the greeks and romans with the assyrians and babylonians, and the ancient greeks and romans with the nations of modern christendom, and it cannot, i think, be questioned that there has been a great superiority in the latter nations, and that their improvements have been subservient to a more exalted state of intellectual and religious existence. if this little globe has been so modified by its powerful and active inhabitants, i cannot help thinking that in other systems beings of a superior nature, under the influence of a divine will, may act nobler parts. we know from the sacred writings that there are intelligences of a higher nature than man, and i cannot help sometimes referring to my vision in the colosaeum, and in supposing some acts of power of those genii or seraphs similar to those which i have imagined in the higher planetary systems. there is much reason to infer from astronomical observations that great changes take place in the system of the fixed stars: sir william herschel, indeed, seems to have believed that he saw nebulous or luminous matter in the process of forming suns, and there are some astronomers who believe that stars have been extinct; but it is more probable that they have disappeared from peculiar motions. it is, perhaps, rather a poetical than a philosophical idea, yet i cannot help forming the opinion that genii or seraphic intelligences may inhabit these systems and may be the ministers of the eternal mind in producing changes in them similar to those which have taken place on the earth. time is almost a human word and change entirely a human idea; in the system of nature we should rather say progress than change. the sun appears to sink in the ocean in darkness, but it rises in another hemisphere; the ruins of a city fall, but they are often used to form more magnificent structures as at rome; but, even when they are destroyed, so as to produce only dust, nature asserts her empire over them, and the vegetable world rises in constant youth, and--in a period of annual successions, by the labours of man providing food--vitality, and beauty upon the wrecks of monuments, which were once raised for purposes of glory, but which are now applied to objects of utility. none none note: project gutenberg also has an html version of this file which includes the original illustrations. see -h.htm or -h.zip: (http://www.gutenberg.org/files/ / -h/ -h.htm) or (http://www.gutenberg.org/files/ / -h.zip) heroes of science. chemists by m. m. pattison muir, m.a., f.r.s.e., fellow, and prælector in chemistry, of gonville and caius college, cambridge. published under the direction of the committee of general literature and education appointed by the society for promoting christian knowledge. london: society for promoting christian knowledge, northumberland avenue, charing cross; , queen victoria street, e.c.; , st. george's place, hyde park corner, s.w. brighton: , north street. new york: e. & j. b. young & co. . "the discoveries of great men never leave us; they are immortal; they contain those eternal truths which survive the shock of empires, outlive the struggles of rival creeds, and witness the decay of successive religions."--buckle. "he who studies nature has continually the exquisite pleasure of discerning or half discerning and divining laws; regularities glimmer through an appearance of confusion, analogies between phenomena of a different order suggest themselves and set the imagination in motion; the mind is haunted with the sense of a vast unity not yet discoverable or nameable. there is food for contemplation which never runs short; you gaze at an object which is always growing clearer, and yet always, in the very act of growing clearer, presenting new mysteries."--the author of "ecce homo." "je länger ich lebe, desto mehr verlern' ich das gelernte, nämlich die systeme."--jean paul richter. preface. i have endeavoured in this book to keep to the lines laid down for me by the publication committee of the society, viz. "to exhibit, by selected biographies, the progress of chemistry from the beginning of the inductive method until the present time." the progress of chemistry has been made the central theme; around this i have tried to group short accounts of the lives of those who have most assisted this progress by their labours. this method of treatment, if properly conducted, exhibits the advances made in science as intimately connected with the lives and characters of those who studied it, and also impresses on the reader the continuity of the progress of natural knowledge. the lives of a few chemists have been written; of others there are, however, only scanty notices to be found. the materials for this book have been collected chiefly from the following works:-- kopp's "geschichte der chemie." thomson's "history of chemistry." ladenburg's "entwickelungsgeschichte der chemie." wurtz's "history of the atomic theory." watts's "dictionary of chemistry." whewell's "history of the inductive sciences." rodwell's "birth of chemistry;" "inquiry into the hermetic mystery and alchemy" (london, ); "popular treatises on science written during the middle ages," edited for the historical society of science by thomas wright, m.a. (london, ); "ripley reviv'd; or, an exposition upon sir george ripley's hermetico-poetical works," by eirenæus philalethes (london, ); "tripus aureus, hoc est tres tractates chymici selectissimi" (frankfurt, ). "alchemy;" article in "encyclopædia britannica." boyle's "sceptical chymist." "biographie universelle;" for notices of berzelius and lavoisier. "english cyclopædia;" for notices of black, berzelius and lavoisier. black's "lectures," with memoir: edited by dr. robinson. priestley's "memoirs:" written partly by himself. priestley's works on "air," etc. lavoisier's "oeuvres." dalton's "life," by dr. henry; "life," by dr. r. angus smith; "new system of chemical philosophy." davy's "collected works;" with life, by his brother; "life," by dr. paris. berzelius's "lehrbuch," and various dissertations. wöhler's "jugenderinnerungen eines chemikers." graham's "collected memoirs." sketch of graham's life, in chemical society's journal. "life-work of liebig," by a. w. hofmann. "dumas," by a. w. hofmann. various dissertations by liebig and dumas in _annalen_, and elsewhere. my warmest thanks are due to my friend, mr. francis rye, for the great assistance he has given me in correcting the proof-sheets. m. m. pattison muir. cambridge, _april, _. contents. page introductory chapter i. alchemy: and the dawn of chemistry. beginnings of natural knowledge--chemistry in the middle ages--alchemy--the phlogistic theory chapter ii. establishment of chemistry as a science--period of black, priestley and lavoisier. introduction of accurate measurements into chemistry--black's researches on alkalis and on fixed air--his conception of heat--priestley's experiments on airs--his discovery of oxygen--lavoisier, the founder of the science of chemistry--he clearly establishes a connection between composition and properties of bodies chapter iii. establishment of general principles of chemical science--period of dalton. dalton's training in physical science--he revives and renders quantitative the atomic theory--the term "atom" is applied by him to elements and compounds alike--his rules for chemical synthesis chapter iv. establishment of general principles of chemical science (_continued_)--period of davy and berzelius. electro-chemistry--the dualistic theory developed by berzelius--davy's work on acids, alkalis, and salts--he proves chlorine to be an element--his discovery of the safety-lamp chapter v. the work of graham. graham traces the movements of molecules--he distinguishes between colloids and cystalloids--dialysis chapter vi. rise and progress of organic chemistry--period of liebig and dumas. the barrier between inorganic and organic chemistry begins to be broken down--wöhler prepares urea--dumas opposes the dualistic system of berzelius--liebig's conception of compound radicles--his work in animal and agricultural chemistry chapter vii. modern chemistry. the relations between composition and properties of bodies are developed and rendered more definite--physical methods are more largely made use of in chemistry--spectroscopic analysis chapter viii. summary and conclusion heroes of science. introductory. as we trace the development of any branch of natural knowledge we find that there has been a gradual progress from vague and fanciful to accurate and definite views of nature. we find that as man's conceptions of natural phenomena become more accurate they also for a time become more limited, but that this limitation is necessary in order that facts may be correctly classified, and so there may be laid the basis for generalizations which, being definite, shall also be capable of expansion. at first nature is strange; she is full of wonderful and fearful appearances. man is overwhelmed by the sudden and apparently irregular outbreaks of storms, by the capricious freaks of thunder and lightning, by the awful and unannounced devastations of the volcano or the earthquake; he believes himself to be surrounded by an invisible array of beings more powerful than himself, but, like himself, changeable in their moods and easily provoked to anger. after a time he begins to find that it is possible to trace points of connection between some of the appearances which had so overpowered or perplexed him. the huntsman observes that certain kinds of plants always grow where the game which he pursues is chiefly to be found; from the appearance of the sky at morning and evening the fisherman is able to tell whether there will follow weather suitable for him to set out in his fishing-boat; the tiller of the ground begins to feel sure that if he sow the seed in the well-dug soil and water it in proper seasons he will certainly reap the harvest in due time. and thus man comes to believe that natural events follow each other in a fixed order; there arises a conscious reference on his part of certain effects to certain definite causes. accurate knowledge has begun. as knowledge of natural appearances advances there comes a time when men devote themselves chiefly to a careful study of some one class of facts; they try to consider that part of nature with which they are mostly concerned as separate from all other parts of nature. thus the various branches of natural knowledge begin to have each a distinct existence. these branches get more and more subdivided, each division is more accurately studied, and so a great number of facts is accumulated in many classes. then we usually find that a master mind arises, who shows the connection which exists between the different parts of each division of natural knowledge, who takes a wide, far-reaching view of the whole range of the province of knowledge which he studies, and who, at the same time, is able to hold in his vision all the important details of each branch of which that province is composed. and thus we again get wide views of nature. but these are very different from the vague, dim and hesitating notions in which natural knowledge had its beginnings. in this later time men see that nature is both simple and complex; that she is more wonderful than their fathers dreamed, but that through all the complexity there runs a definite purpose; that the apparently separate facts are bound together by definite laws, and that to discover this purpose and these laws is possible for man. as we trace this progress in the various branches of natural knowledge we are struck with the fact that each important advance is generally accomplished by one or two leading men; we find that it becomes possible to group the history of each period round a few central figures; and we also learn that the character of the work done by each of these men of note is dependent on the nature and training of the individual man. it will be my endeavour in the following pages to give an account of the advance of chemical science, grouping the facts in each stage of progress round the figures of one or two men who were prominent in that period. for the purposes of this book it will be necessary that i should sketch only the most important periods in the story of chemical progress, and that in each of these i should fill in the prominent points alone. i shall therefore select three periods in the progress of this science, and try to give an account of the main work done in each of these. and the periods will be:-- i. the period wherein, chiefly by the work of black, priestley and lavoisier, the aim of chemical science was defined and the essential characters of the phenomena to be studied were clearly stated. ii. the period during which, chiefly by the labours of dalton, berzelius and davy, the great central propositions of the science were laid down and were developed into a definite theory. as belonging in great extent to this period, although chronologically later, i shall also consider the work of graham. iii. the period when, chiefly owing to advances made in organic chemistry, broader and more far-reaching systems of classification were introduced, and the propositions laid down in the preceding period were modified and strengthened. the workers in this period were very numerous; i shall chiefly consider these two--liebig and dumas. i shall conclude with a brief sketch of some of the important advances of chemical science in more recent times, and a summary of the characteristics of each of the three periods. chapter i. alchemy: and the dawn of chemistry. early chemistry was not a science. the ancient chemists dealt chiefly with what we should now call chemical manufactures; they made glass, cleaned leather, dyed cloth purple and other colours, extracted metals from their ores, and made alloys of metals. no well-founded explanations of these processes could be expected either from men who simply used the recipes of their predecessors, or from philosophers who studied natural science, not by the help of accurate experiments, but by the unaided light of their own minds. at somewhat later times chemistry assumed a very important place in the general schemes propounded by philosophers. change is vividly impressed on all man's surroundings: the endeavour to find some resting-place amidst the chaos of circumstances, some unchanging substance beneath the ever-changing appearances of things, has always held a prominent place with those who study the phenomena of the world which surrounds them. in the third and fourth centuries of our era much attention was given to the art which professed to explain the changes of nature. religion, philosophy, and what we should now call natural science, were at that time closely intermingled; the scheme of things which then, and for several centuries after that time, exerted a powerful influence over the minds of many thinkers was largely based on the conception of a fundamental unity underlying and regulating the observed dissimilarities of the universe. thus, in the _emerald table of hermes_, which was held in much repute in the middle ages, we read-- "true, without error, certain and most true: that which is above is as that which is below, and that which is below is as that which is above, for performing the miracles of the _one thing_; and as all things were from one, by the mediation of one, so all things arose from this one thing by adaptation: the father of it is the sun, the mother of it is the moon, the wind carried it in its belly, the nurse of it is the earth. this is the father of all perfection, the consummation of the whole world." and again, in a later writing we have laid down the basis of the art of alchemy in the proposition that "there abides in nature a certain pure matter, which, being discovered and brought by art to perfection, converts to itself proportionally all imperfect bodies that it touches." to discover this fundamental principle, this _one thing_, became the object of all research. earth and the heavens were supposed to be bound together by the all-pervading presence of the one thing; he who should attain to a knowledge of this precious essence would possess all wisdom. to the vision of those who pursued the quest for the one thing the whole universe was filled by one ever-working spirit, concealed now by this, now by that veil of sense, ever escaping identification in any concrete form, yet certainly capable of being apprehended by the diligent searcher. analogy was the chief guide in this search. if it were granted that all natural appearances were manifestations of the activity of one essential principle, then the vaguest and most far-fetched analogies between the phenomena of nature might, if properly followed up, lead to the apprehension of this hidden but everywhere present essence. the history of alchemy teaches, in the most striking manner, the dangers which beset this method of pursuing the study of nature; this history teaches us that analogies, unless founded on carefully and accurately determined facts, are generally utterly misleading in natural science. let us consider the nature of the experimental evidence which an alchemist of the fourth or fifth century could produce in favour of his statement that transmutation of one kind of matter into another is of constant occurrence in nature. the alchemist heated a quantity of water in an open glass vessel; the water slowly disappeared, and when it was all gone there remained in the vessel a small quantity of a white earthy solid substance. what could this experiment teach save that water was changed into earth and air? the alchemist then plunged a piece of red-hot iron into water placed under a bell-shaped glass vessel; some of the water seemed to be changed into air, and a candle, when brought into the bell, caused the air therein to take fire. therefore, concluded the experimenter, water is proved to be changeable into fire. a piece of lead was then strongly heated in the air; it lost its lustre and became changed into a reddish-white powder, very unlike lead in its properties; this powder was then heated in a convenient vessel with a little wheat, whereupon the lead was again produced. therefore, said the alchemist, lead is destroyed by fire, but it can be reproduced from its ashes by the help of heat and a few grains of corn. the experimenter would now proceed to heat a quantity of a mineral containing lead in an open vessel made of pulverized bones; the lead slowly disappeared, and at the close of the experiment a button of silver remained. might he not triumphantly assert that he had transmuted lead into silver? in order that the doctrine of the transmutation of metals might rest on yet surer evidence, the alchemist placed a piece of copper in spirits of nitre (nitric acid); the metal disappeared; into the green liquid thus produced he then placed a piece of iron; the copper again made its appearance, while the iron was removed. he might now well say that if lead was thus demonstrably changed into silver, and copper into iron, it was, to say the least, extremely probable that any metal might be changed into any other provided the proper means for producing the change could be discovered. but the experimental alchemist had a yet stranger transmutation wherewith to convince the most sceptical. he poured mercury in a fine stream on to melted sulphur; at once the mercury and the sulphur disappeared, and in their place was found a solid substance black as the raven's wing. he then heated this black substance in a closed vessel, when it also disappeared, and in its place there was found, deposited on the cooler part of the vessel, a brilliantly red-coloured solid. this experiment taught lessons alike to the alchemist, the philosopher, and the moralist of these times. the alchemist learned that to change one kind of matter into another was an easy task: the philosopher learned that the prevalence of change or transmutation is one of the laws of nature: and the moralist learned that evil is not wholly evil, but contains also some germs of good; for was not the raven-black substance emblematical of the evil, and the red-coloured matter of the good principle of things?[ ] on such experimental evidence as this the building of alchemy was reared. a close relationship was believed to prevail through the whole phenomena of nature. what more natural then than to regard the changes which occur among the forms of matter on this earth as intimately connected with the changes which occur among the heavenly bodies? man has ever been overawed by the majesty of the stars; yet he has not failed to notice that the movements of these bodies are apparently capricious. the moon has always been to him a type of mutability; only in the sun has he seemed to find a settled resting-point. now, when we remember that in the alchemical scheme of things the material earth and material heavens, the intellectual, the moral, and the spiritual world were regarded as one great whole, the parts of which were continuously acting and reacting on each other, we cannot wonder that the alchemist should regard special phenomena which he observed in his laboratory, or special forms of matter which he examined, as being more directly than other phenomena or other forms of matter, under the influence of the heavenly bodies. this connection became gradually more apparent to the student of alchemy, until at last it was fixed in the language and the symbols which he employed. thus the sun (sol) was represented by a circle, which likewise became the symbol for gold, as being the most perfect metal. the moon (luna) was ever changing; she was represented by a half-circle, which also symbolized the pale metal silver. copper and iron were regarded as belonging to the same class of metals as gold, but their less perfect nature was denoted by the sign + or ^. tin and lead belonged to the lunar class, but like copper they were supposed to be imperfect metals. mercury was at once solar and lunar in its properties. these suppositions were summed up in such alchemical symbols as are represented below-- [illustration: sol. gold.] [illustration: luna. silver.] [illustration: venus. copper.] [illustration: mars. iron.] [illustration: jupiter. tin.] [illustration: saturn. lead.] [illustration: mercury. quicksilver.] many of the alchemical names remain to the present time; thus in pharmacy the name "lunar caustic" is applied to silver nitrate, and the symptoms indicative of lead-poisoning are grouped together under the designation of "saturnine cholic." but as the times advanced the older and nobler conception of alchemy became degraded. if it be true, the later alchemists urged, that all things suffer change, but that a changeless essence or principle underlies all changing things, and that the presence of more or less of this essence confers on each form of matter its special properties, it follows that he who can possess himself of this principle will be able to transmute any metal into any other; he will be able to change any metal into gold. now, as the possession of gold has always carried with it the means of living luxuriously, it is easy to understand how, when this practical aspect of alchemy had taken firm root in men's minds, the pursuit of the art became for all, except a few lofty and noble spirits, synonymous with the pursuit of wealth. so that we shall not, i think, much err if we describe the chemistry of the later middle ages as an effort to accumulate facts on which might be founded the art of making gold. in one respect this was an advance. in the early days of alchemy there had been too much trusting to the mental powers for the manufacture of natural facts: chemists now actually worked in laboratories; and very hard did many of these alchemists work. paracelsus says of the alchemists, "they are not given to idleness, nor go in a proud habit, or plush and velvet garments, often showing their rings upon their fingers, or wearing swords with silver hilts by their sides, or fine and gay gloves upon their hands; but diligently follow their labours, sweating whole days and nights by their furnaces. they do not spend their time abroad for recreation, but take delight in their laboratory. they put their fingers amongst coals, into clay and filth, not into gold rings. they are sooty and black like smiths and miners, and do not pride themselves upon clean and beautiful faces." by thus "taking delight in their laboratories" the later alchemists gathered together many facts; but their work centred round one idea, viz. that metals might all be changed into gold, and this idea was the result rather of intellectual guessing than of reasoning on established facts of nature. one of the most famous alchemists of the middle ages was born at einsiedeln, in switzerland, in . his name, when paraphrased into greek, became paracelsus. this man, some of whose remarks have just been quoted, acquired great fame as a medical practitioner, and also as a lecturer on medicine: he travelled throughout the greater part of europe, and is supposed to have been taught the use of several new medicines by the arabian physicians whom he met in spain. with an over-weening sense of his own powers, with an ardent and intemperate disposition, revolting against all authority in medicine or science, paracelsus yet did a good work in calling men to the study of nature as the only means whereby natural science could be advanced. "alchemy has but one aim and object," paracelsus taught: "to extract the quintessence of things, and to prepare arcana and elixirs which may serve to restore to man the health and soundness he has lost." he taught that the visible universe is but an outer shell or covering, that there is a spirit ever at work underneath this veil of phenomena; but that all is not active: "to separate the active function (the spirit) of this outside shell from the passive" was, he said, the proper province of alchemy. paracelsus strongly insisted on the importance of the changes which occur when a substance burns, and in doing this he prepared the way for stahl and the phlogistic chemists. however we may admire the general conceptions underlying the work of the earlier alchemists, we must admit that the method of study which they adopted could lead to very few results of lasting value; and i think we may add that, however humble the speculations of these older thinkers might appear, this humility was for the most part only apparent. these men were encompassed (as we are) by unexplained appearances: they were every moment reminded that man is not "the measure of all things;" and by not peering too anxiously into the mysteries around them, by drawing vague conclusions from partially examined appearances, they seemed at once to admit their own powerlessness and the greatness of nature. but i think we shall find, as we proceed with our story, that this is not the true kind of reverence, and that he is the really humble student of nature who refuses to overlook any fact, however small, because he feels the tremendous significance of every part of the world of wonders which it is his business and his happiness to explore. as examples of the kind of explanation given by alchemists of those aspects of nature which they professed to study, i give two quotations from translations of the writings of basil valentine and paracelsus, who flourished in the first half of the fifteenth and sixteenth centuries respectively. "think most diligently about this; often bear in mind, observe and comprehend that all minerals and metals together, in the same time, and after the same fashion, and of one and the same principal matter, are produced and generated. that matter is no other than a mere vapour, which is extracted from the elementary earth by the superior stars, or by a sidereal distillation of the macrocosm; which sidereal hot infusion, with an airy sulphureous property, descending upon inferiors, so acts and operates as that there is implanted, spiritually and invisibly, a certain power and virtue in those metals and minerals; which fume, moreover, resolves in the earth into a certain water wherefrom all metals are thenceforth generated and ripened to their perfection, and thence proceeds this or that metal or mineral, according as one of the three principles acquires dominion and they have much or little of sulphur and salt, or an unequal mixture of these; whence some metals are fixed, that is, constant or stable; and some are volatile and easily changeable, as is seen in gold, silver, copper, iron, tin and lead." "the life of metals is a secret fatness; of salts, the spirit of aqua fortis; of pearls, their splendour; of marcasites and antimony, a tingeing metalline spirit; of arsenics, a mineral and coagulated poison. the life of all men is nothing else but an astral balsam, a balsamic impression, and a celestial invisible fire, an included air, and a tingeing spirit of salt. i cannot name it more plainly, although it is set out by many names." when the alchemists gave directions for making the stone which was to turn all it touched into gold, they couched them in such strange and symbolical language as this: "after our serpent has been bound by her chain, penetrated with the blood of our green dragon, and driven nine or ten times through the combustible fire into the elementary air, if you do not find her to be exceeding furious and extremely penetrating, it is a sign that you do not hit our subject, the notion of the homogenea, or their proportion; if this furious serpent does not come over in a cloud and turn into our virgin milk, or argentine water, not corrosive at all and yet insensibly and invisibly devouring everything that comes near it, it is plainly to be seen that you err in the notion of our universal menstruum." or, again, what could any reasonable man make of this? "in the green lion's bed the sun and moon are born; they are married and beget a king. the king feeds on the lion's blood, which is the king's father and mother, who are at the same time his brother and sister. i fear i betray the secret, which i promised my master to conceal in dark speech from any one who knows not how to rule the philosopher's fire." concerning the same lion, another learned author says that "though called a lion, it is not an animal substance, but for its transcendant force, and the rawness of its origin, it is called the green lion." but he adds in a moment of confidence: "this horrid beast has so many names, that unless god direct the searcher it is impossible to distinguish him." and once more. "take our two serpents, which are to be found everywhere on the face of the earth: tie them in a love-knot and shut them up in the arabian _caraha_. this is the first labour; but the next is more difficult. thou must encamp against them with the fire of nature, and be sure thou dost bring thy line round about. circle them in and stop all avenues that they find no relief. continue this siege patiently, and they turn into an ugly venomous black toad, which will be transformed to a horrible devouring dragon, creeping and weltering in the bottom of her cave without wings. touch her not by any means, for there is not on earth such a vehement transcending poison. as thou hast begun so proceed, and this dragon will turn into a swan. henceforth i will show thee how to fortify thy fire till the phoenix appear: it is a red bird of a most deep colour, with a shining fiery hue. feed this bird with the fire of his father and the ether of his mother: for the first is meat and the second is drink, and without this last he attains not to his full glory. be sure to understand this secret," etc., etc. the alchemists spoke of twelve gates through which he who would attain to the palace of true art must pass: these twelve gates were to be unlocked by twelve keys, descriptions of which, couched in strange and symbolical language, were given in alchemical treatises. thus in "ripley reviv'd"[ ] we read that canon ripley, of bridlington, who lived in the time of edward iv., sang thus of the first gate, which was "calcination:"-- "the battle's fought, the conquest won, the lyon dead reviv'd; the eagle's dead which did him slay, and both of sense depriv'd. the showers cease, the dews which fell for six weeks do not rise; the ugly toad that did so swell with swelling bursts and dies." and of the third gate, or "conjunction," we find the canon saying-- "he was a king, yet dead as dead could be; his sister a queen, who when her brother she did breathless see, the like was never seen, she cryes until her eyes with over-weeping were waxed dim-- so long till her tears reach'd up to her ears: the queen sunk, but the king did swim." in some books these gates and keys are symbolically represented in drawings, _e.g._ in a pamphlet by paracelsus, called "tripus aureus, hoc est tres tractates chymici selectissimi." (frankfurt, .) it is evident that a method of studying nature which resulted in such dim and hazy explanations as these was eminently fitted to produce many who pretended to possess secrets by the use of which they could bring about startling results beyond the power of ordinary men; and, at the same time, the almost universal acceptance of such statements as those i have quoted implied the existence in men generally of a wondrous readiness to believe anything and everything. granted that a man by "sweating whole days and nights by his furnaces" can acquire knowledge which gives him great power over his fellows, it necessarily follows that many will be found ready to undergo these days and nights of toil. and when we find that this supposed knowledge is hidden under a mask of strange and mystical signs and language, we may confidently assert that there will be many who learn to repeat these strange terms and use these mystical signs without attempting to penetrate to the truths which lie behind--without, indeed, believing that the mystical machinery which they use has any real meaning at all. we find, as a matter of fact, that the age of the alchemists produced many deceivers, who, by mumbling incantations and performing a few tricks, which any common conjuror would now despise, were able to make crowds of men believe that they possessed a supernatural power to control natural actions, and, under this belief, to make them part with their money and their substance. one respectable physician of the hague, who entertained a peripatetic alchemist, complains that the man entered his "best-furnished room without wiping his shoes, although they were full of snow and dirt." however, the physician was rewarded, as the stranger gave him, "out of his philosophical commiseration, as much as a turnip seed in size" of the much-wished-for stone of wisdom. that the alchemist of popular belief was a man who used a jargon of strange and high-sounding words, that he might the better deceive those whom he pretended to help, is evident from the literature of the sixteenth and seventeenth centuries. in the play of the "alchymist" ben jonson draws the character of subtle as that of a complete scoundrel, whose aim is to get money from the pockets of those who are stupid enough to trust him, and who never hesitates to use the basest means for this end. from the speeches of subtle we may learn the kind of jargon employed by the men who pretended that they could cure diseases and change all baser metals into gold. "_subtle._ name the vexations and the martyrizations of metals in the work. _face._ sir, putrefaction, solution, ablution, sublimation, cohobation, calcination, ceration, and fixation. _sub._ and when comes vivification? _face._ after mortification. _sub._ what's cohobation? _face._ 'tis the pouring on your aqua regis, and then drawing him off, to the trine circle of the seven spheres. * * * * * _sub._ and what's your mercury? _face._ a very fugitive; he will be gone, sir. _sub._ how know you him? _pace._ by his viscosity, his oleosity, and his suscitability." even in the fourteenth century, chaucer (in the "canon's yeoman's tale") depicts the alchemist as a mere cunning knave. a priest is prevailed on to give the alchemist money, and is told that he will be shown the change of base metal into gold. the alchemist busies himself with preparations, and sends the priest to fetch coals. "and whil he besy was, this feendly wrecche, this false chanoun (the foule feende him fecche) out of his bosom took a bechen cole in which ful subtilly was maad an hole, and therein put was of silver lymayle an unce, and stopped was withoute fayle the hole with wex, to keep the lymayle in. and understondith, that this false gyn was not maad there, but it was maad before." this "false gyn" having been put in the crucible and burned with the rest of the ingredients, duly let out its "silver lymayle" (filings), which appeared in the shape of a small button of silver, and so accomplished the "false chanoun's" end of deceiving his victim. the alchemists accumulated many facts: they gained not a little knowledge concerning the appearances of nature, but they were dominated by a single idea. living in the midst of an extremely complex order of things, surrounded by a strange and apparently capricious succession of phenomena, they were convinced that the human intelligence, directed and aided by the teachings of the church, would guide them through the labyrinth. and so they entered on the study of nature with preconceived notions and foregone conclusions: enthusiastic and determined to know although many of them were, they nevertheless failed because they refused to tread the only path which leads to true advances in natural science--the path of unprejudiced accurate experiment, and of careful reasoning on experimentally determined facts. and even when they had become convinced that their aims were visionary, they could not break free from the vicious system which bound them. "... i am broken and trained to my old habits: they are part of me. i know, and none so well, my darling ends are proved impossible: no less, no less, even now what humours me, fond fool, as when their faint ghosts sit with me and flatter me, and send me back content to my dull round."[ ] one of the most commonly occurring and most noticeable changes in the properties of matter is that which proceeds when a piece of wood, or a candle, or a quantity of oil burns. the solid wood, or candle, or the liquid oil slowly disappears, and this disappearance is attended with the visible formation of flame. even the heavy fixed metals, tin or lead, may be caused to burn; light is produced, a part of the metal seems to disappear, and a white (or reddish) solid, very different from the original metal, remains. the process of burning presents all those peculiarities which are fitted to strike an observer of the changes of nature; that is, which are fitted to strike a chemist--for chemistry has always been recognized as having for its object to explain the changes which matter undergoes. the chemists of the seventeenth and eighteenth centuries were chiefly occupied in trying to explain this process of burning or combustion. van helmont ( - ), who was a physician and chemist of brussels, clearly distinguished between common air and other "airs" or gases produced in different ways. robert hooke ( - ), one of the original fellows of the royal society, in the "micographia, or philosophical description of minute bodies," published in , concluded from the results of numerous experiments that there exists in common air a peculiar kind of gas, similar to, or perhaps identical with the gas or air which is got by heating saltpetre; and he further supposed that when a solid burns, it is dissolved by (or we should now say, it is converted into a gas by combining with) this peculiar constituent of the air. john mayow ( - ), a physician of oxford, experimented on the basis of facts established by hooke. he showed that when a substance, _e.g._ a candle, burns in air, the volume of air is thereby lessened. to that portion of the air which had _dissolved_ the burned substance he gave the name of _nitre-air_, and he argued that this air exists in condensed form in nitre, because sulphur burns when heated with nitre in absence of common air. mayow added the most important fact--a fact which was forgotten by many later experimenters--that the solid substance obtained by burning a metal in air weighs more than the metal itself did before burning. he explained this increase in weight by saying that the burning metal absorbs particles of "nitre-air" from the atmosphere. thus hooke and mayow had really established the fact that common air consists of more than one definite kind of matter--in other words, that common air is not an element; but until recent times the term "element" or "elementary principle" was used without any definite meaning. when we say that the ancients and the alchemists recognized four elements--earth, air, fire, and water--we do not attach to the word "element" the same definite meaning as when we now say, "iron is an element." from earth, air, fire and water other substances were obtained; or it might be possible to resolve other substances into one or more of these four. but even to such a word as "substance" or "matter" no very definite meaning could be attached. although, therefore, the facts set forth by hooke and mayow might now justify the assertion that air is not an element, they did not, in the year , necessarily convey this meaning to men's minds. the distinction between element and compound was much more clearly laid down by the hon. robert boyle ( - ), whose chemical work was wonderfully accurate and thorough, and whose writings are characterized by acute scientific reasoning. we shall again return to these terms "element" and "compound." but the visible and striking phenomenon in most processes of burning is the production of light and sometimes of flame. the importance of the fact that the burned substance (when a solid) weighs more than the unburned substance was overshadowed by the apparent importance of the outward part of the process, which could scarcely be passed over by any observer. there appears to be an outrush of _something_ from the burning substance. there _is_ an outrush of something, said becher and stahl, and this something is the "principle of fire." the principle of fire, they said, is of a very subtle nature; its particles, which are always in very rapid motion, can penetrate any substance, however dense. when metals burn--the argument continued--they lose this principle of fire; when the burned metal--or _calx_ as it was usually called--is heated with charcoal it regains this "principle," and so the metal is re-formed from the calx. thus arose the famous theory of _phlogiston_ (from greek, = "burned"), which served as a central nucleus round which all chemical facts were grouped for nearly a hundred years. john joachim becher was born at speyer in , and died in ; in his chemical works, the most important of which is the "physica subterranea," he retained the alchemical notion that the metals are composed of three "principles"--the nitrifiable, the combustible, and the mercurial--and taught that during calcination the combustible and mercurial principles are expelled, while the nitrifiable remains in the calx. george ernest stahl--born at anspach in , and died at berlin in --had regard chiefly to the principles which escape during the calcination of metals, and simplifying, and at the same rendering more definite the idea of becher, he conceived and enunciated the theory of phlogiston. but if _something_ (name it "phlogiston" or call it by any other name you please) is lost by a metal when the metal is burned, how is it that the loss of this thing is attended with an increase in the weight of the matter which loses it? either the theory of phlogiston must be abandoned, or the properties of the _thing_ called phlogiston must be very different from those of any known kind of matter. stahl replied, phlogiston is a "principle of levity;" the presence of phlogiston in a substance causes that substance to weigh less than it did before it received this phlogiston. in criticizing this strange statement, we must remember that in the middle of the seventeenth century philosophers in general were not firmly convinced of the truth that the essential character of matter is that it possesses weight, nor of the truth that it is impossible to destroy or to create any quantity of matter however small. it was not until the experimental work of lavoisier became generally known that chemists were convinced of these truths. nevertheless, the opponents of the stahlian doctrine were justified in asking for further explanations--in demanding that some other facts analogous to this supposed fact, viz. that a substance can weigh less than nothing, should be experimentally established. the phlogistic theory however maintained its ground; we shall find that it had a distinct element of truth in it, but we shall also find that it did harm to scientific advance. this theory was a wide and sweeping generalization from a few facts; it certainly gave a central idea around which some facts might be grouped, and it was not very difficult, by slightly cutting down here and slightly adding there, to bring many new discoveries within the general theory. we now know that in order to explain the process of combustion much more accurate knowledge was required than the chemists of the seventeenth century possessed; but we ought to be thankful to these chemists, and notably to stahl, that they did not hesitate to found a generalization on the knowledge they had. almost everything propounded in natural science has been modified as man's knowledge of nature has become wider and more accurate; but it is because the scientific student of nature uses the generalizations of to-day as stepping-stones to the better theories of to-morrow, that science grows "from more to more." looking at the state of chemistry about the middle of the eighteenth century, we find that the experiments, and especially the measurements, of hooke and mayow had laid a firm basis of fact concerning the process of combustion, but that the phlogistic theory, which appeared to contradict these facts, was supreme; that the existence of airs, or gases, different from common air was established, but that the properties of these airs were very slightly and very inaccurately known; that boyle had distinguished element from compound and had given definite meanings to these terms, but that nevertheless the older and vaguer expression, "elementary principle," was generally used; and lastly, that very few measurements of the masses of the different kinds of matter taking part in chemical changes had yet been made. footnotes: [ ] i have borrowed these illustrations of the alchemical, experimental method from m. hoefer's "histoire de la chimie," quoted in the "encyclopædia brittanica," art. "alchemy." [ ] "ripley reviv'd: or an exposition upon sir george ripley's hermetico-poetical works," by eirenæus philalethes. london, . [ ] browning's "paracelsus." chapter ii. establishment of chemistry as a science--period of black, priestley and lavoisier. _joseph black_, - . _joseph, priestley_, - . _antoine laurent lavoisier_, - . during this period of advance, which may be broadly stated as comprising the last half of the eighteenth century, the aim and scope of chemical science were clearly indicated by the labours of black, priestley and lavoisier. the work of these men dealt chiefly with the process of combustion. black and priestley finally proved the existence of airs or gases different from common air, and lavoisier applied these discoveries to give a clear explanation of what happens when a substance burns. * * * * * joseph black was born near bordeaux in the year . his father was of scottish family, but a native of belfast; his mother was the daughter of mr. gordon, of hilhead in aberdeenshire. we are told by dr. robison, in his preface to black's lectures, that john black, the father of joseph, was a man "of most amiable manners, candid and liberal in his sentiments, and of no common information." at the age of twelve black was sent home to a school at belfast; after spending six years there he went to the university of glasgow in the year . little is known of his progress at school or at the university, but judging from his father's letters, which his son preserved, he seems to have devoted himself to study. while at glasgow he was attracted to the pursuit of physical science, and chose medicine as a profession. becoming a pupil of dr. cullen, he was much impressed with the importance of chemical knowledge to the student of medicine. dr. cullen appears to have been one of the first to take large and philosophical views of the scope of chemical science, and to attempt to raise chemistry from the rank of a useful art to that of a branch of natural philosophy. such a man must have been attracted by the young student, whose work was already at once accurate in detail and wide in general scope. in the notes of work kept by black at this time are displayed those qualities of methodical arrangement, perseverance and thoroughness which are so prominent in his published investigations and lectures. in one place we find, says his biographer, many disjointed facts and records of diverse observations, but the next time he refers to the same subjects we generally have analogous facts noted and some conclusions drawn--we have the beginnings of knowledge. having once entered on an investigation black works it out steadily until he gets definite results. his earlier notes are concerned chiefly with heat and cold; about he begins to make references to the subject of "fixed air." about black went to edinburgh university to complete his medical studies, and here he was again fortunate in finding a really scientific student occupying the chair of natural philosophy. the attention of medical men was directed at this time to the action of limewater as a remedy for stone in the bladder. all the medicines which were of any avail in mitigating the pain attendant on this disease more or less resembled the "caustic ley of the soap-boilers" (or as we should now call it caustic potash or soda). these caustic medicines were mostly prepared by the action of quicklime on some other substance, and quicklime was generally supposed to derive its caustic, or corrosive properties from the fire which was used in changing ordinary limestone into quicklime. when quicklime was heated with "fixed alkalis" (_i.e._ with potassium or sodium carbonate), it changed these substances into caustic bodies which had a corrosive action on animal matter; hence it was concluded that the quicklime had derived a "power"--or some said had derived "igneous matter"--from the fire, and had communicated this to the fixed alkalis, which thereby acquired the property of corroding animal matter. black thought that he might be able to lay hold of this "igneous matter" supposed to be taken by the limestone from the fire; but he found that limestone loses weight when changed into quicklime. he then dissolved limestone (or chalk) in spirits of salt (hydrochloric acid), and compared the loss of weight undergone by the chalk in this process with the loss suffered by an equal quantity of chalk when strongly heated. this investigation led black to a fuller study of the action of heat on chalk and on "mild magnesia" (or as we now say, magnesium carbonate). in order that his experiments might be complete and his conclusions well established, he delayed taking the degree of doctor of medicine for three years. he graduated as m. d. in , and presented his thesis on "magnesia alba, quicklime and other alkaline substances," which contained the results of what is probably the first accurately quantitative examination of a chemical action which we possess. black prepared mild magnesia (magnesium carbonate) by boiling together solutions of epsom salts (magnesium sulphate) and fixed alkali (potassium carbonate). he showed that when mild magnesia is heated-- . it is much decreased in bulk. . it loses weight (twelve parts become five, according to black). . it does not precipitate lime from solutions of that substance in acids (black had already shown that mild magnesia does precipitate lime). he then strongly heated a weighed quantity of mild magnesia in a retort connected with a receiver; a few drops of water were obtained in the receiver, but the magnesia lost six or seven times as much weight as the weight of the water produced. black then recalls the experiments of hales, wherein airs other than common air had been prepared, and concludes that the loss of weight noticed when mild magnesia is calcined is probably due to expulsion, by the heat, of some kind of air. dissolving some of his mild magnesia in acid he noticed that effervescence occurred, and from this he concluded that the same air which, according to his hypothesis, is expelled by heat, is also driven out from the mild magnesia by the action of acid. he then proceeded to test this hypothesis. one hundred and twenty grains of mild magnesia were strongly calcined; the calcined matter, amounting to seventy grains, was dissolved in dilute oil of vitriol, and this solution was mixed with common fixed alkali (potassium carbonate). the solid which was thus produced was collected, washed and weighed; it amounted to a trifle less than one hundred and twenty grains, and possessed all the properties--detailed by black--of the original mild magnesia. but this is exactly the result which ought to have occurred according to his hypothesis. the next step in the investigation was to collect the peculiar air which black had proved to be evolved during the calcination of mild magnesia. to this substance he gave the name of "fixed air," because it was fixed or held by magnesia. black established the existence of this air in the expired breath of animals, and also showed that it was present in the air evolved during vinous fermentation. he demonstrated several of its properties; among these, the fact that animals die when placed in this air. an air with similar properties was obtained by calcining chalk. black held that the chemical changes which occur when chalk is calcined are exactly analogous to those which he had proved to take place when magnesia is strongly heated. chalk ought therefore to lose weight when calcined; the residue ought to neutralize an acid without evolution of any gas, and the quantity of acid thus neutralized ought to be the same as would be neutralized by the uncalcined chalk; lastly, it ought to be possible to recover the uncalcined chalk by adding a fixed alkali to a solution of the calcined chalk or quicklime. the actual results which black obtained were as follows:-- one hundred and twenty grains of chalk were dissolved in dilute muriatic (hydrochloric) acid; grains of the acid were needed to neutralize the chalk, and grains of fixed air were evolved. one hundred and twenty grains of the same specimen of chalk were strongly calcined, and then dissolved in dilute muriatic acid; grains of the acid were required to neutralize the calcined chalk. the difference between and is very slight; considering the state of practical chemistry at black's time, we may well agree with him that he was justified in the conclusion that equal weights of calcined and of uncalcined chalk neutralize the same amount of acid. one hundred and twenty grains of the same specimen of chalk were again strongly heated; the calcined chalk, amounting to grains, was digested with a solution of fixed alkali in water. the substance thus obtained, when washed and dried, weighed grains, and had all the properties of ordinary chalk. therefore, said black, it is possible to recover the whole of the chalk originally present before calcination, by adding a fixed alkali to the calcined chalk or quicklime. at this time it was known that water dissolves quicklime, but it was generally held that only about one-fourth (or perhaps a little more) of any specimen of quicklime could be dissolved by water, however much water was employed. black's researches had led him to regard quicklime as a homogeneous chemical compound; he concluded that as water undoubtedly dissolves quicklime to some extent, any specimen of this substance, provided it be pure, must be wholly soluble in water. carefully conducted experiments proved that black's conclusion was correct. black had thus proved that quicklime is a definite substance, with certain fixed properties which characterize it and mark it off from all other substances; that by absorbing, or combining with another definite substance (fixed air), quicklime is changed into a third substance, namely chalk, which is also characterized by properties as definite and marked as those of quicklime or fixed air. black, quite as much as the alchemists, recognized the fact that change is continually proceeding in nature; but he clearly established the all-important conclusion that these natural changes proceed in definite order, and that it is possible by careful experiment and just reasoning to acquire a knowledge of this order. he began the great work of showing that, as in other branches of natural science, so also in chemistry, which is pre-eminently the study of the changes of nature, "the only distinct meaning of that word" (natural) "is _stated_, _fixed_, or _settled_" (butler's "analogy," published ). this research by black is a model of what scientific work ought to be. he begins with a few observations of some natural phenomenon; these he supplements by careful experiments, and thus establishes a sure basis of fact; he then builds on this basis a general hypothesis, which he proceeds to test by deducing from it certain necessary conclusions, and proving, or disproving, these by an appeal to nature. this is the scientific method; it is common sense made accurate. very shortly after the publication of the thesis on magnesia and quicklime, a vacancy occurred in the chemical chair in glasgow university, and black was appointed professor of anatomy and lecturer on chemistry. as he did not feel fully qualified to lecture on anatomy, he made an arrangement to exchange subjects with the professor of medicine, and from this time he delivered lectures on chemistry and on "the institutes of medicine." black devoted a great deal of care and time to the teaching duties of his chair. his chemical experimental researches were not much advanced after this time; but he delivered courses of lectures in which new light was thrown on the whole range of chemical science. in the years between and black examined the phenomena of heat and cold, and gave an explanation, founded on accurate experiments, of the thermal changes which accompany the melting of solids and the vaporization of liquids. if pieces of wood, lead and ice be taken by the hand from a box in which they have been kept cold, the wood feels cold to the touch, the lead feels colder than the wood, and the ice feels colder than the lead; hence it was concluded that the hand receives cold from the wood, more cold from the lead, and most cold from the ice. black however showed that the wood really takes away heat from the hand, but that as the wood soon gets warmed, the process stops before long; that the lead, not being so quickly warmed as the wood, takes away more heat from the hand than the wood does, and that the ice takes away more heat than either wood or lead. black thought that the heat which is taken by melting ice from a warm body remains in the water which is produced; as soon as winter came he proceeded to test this supposition by comparing the times required to melt one pound of ice and to raise the temperature of one pound of water through one degree, the source of heat being the same in each case. he also compared the time required to lower the temperature of one pound of water through one degree with that required to freeze one pound of ice-cold water. he found that in order to melt one pound of ice without raising its temperature, as much heat had to be added to the ice as sufficed to raise the temperature of one pound of water through about degrees of fahrenheit's thermometer. but this heat which has been added to the ice to convert it into water is not indicated by the thermometer. black called this "_latent heat_." the experimental data and the complete theory of latent heat were contained in a paper read by black to a private society which met in the university of glasgow, on april , ; but it appears that black was accustomed to teach the theory in his ordinary lectures before this date. the theory of latent heat ought also to explain the phenomena noticed when liquid water is changed into steam. black applied his theory generally to this change, but did not fully work out the details and actually measure the quantity of heat which is absorbed by water at the boiling point before it is wholly converted into steam at the same temperature, until some years later when he had the assistance of his pupil and friend james watt. taking a survey of the phenomena of nature, black insisted on the importance of these experimentally established facts--that before ice melts it must absorb a large quantity of heat, and before water is vaporized it must absorb another large quantity of heat, which amounts of heat are restored to surrounding substances when water vapour again becomes liquid water and when liquid water is congealed to ice. he allows his imagination to picture the effects of these properties of water in modifying and ameliorating the climates of tropical and of northern countries. in his lectures he says, "here we can also trace another magnificent train of changes which are nicely accommodated to the wants of the inhabitants of this globe. in the equatorial regions, the oppressive heat of the sun is prevented from a destructive accumulation by copious evaporation. the waters, stored with their vaporific heat, are then carried aloft into the atmosphere till the rarest of the vapour reaches the very cold regions of the air, which immediately forms a small portion of it into a fleecy cloud. this also further tempers the scorching heat by its opacity, performing the acceptable office of a screen. from thence the clouds are carried to the inland countries, to form the sources in the mountains which are to supply the numberless streams that water the fields. and by the steady operation of causes, which are tolerably uniform, the greater part of the vapours passes on to the circumpolar regions, there to descend in rains and dews; and by this beneficent conversion into rain by the cold of those regions, each particle of steam gives up the heat which was latent in it. this is immediately diffused, and softens the rigour of those less comfortable climates." in the year black was appointed professor of chemistry in the university of edinburgh, in which position he remained till his death in . during these thirty-three years he devoted himself chiefly to teaching and to encouraging the advance of chemical science. he was especially careful in the preparation of his elementary lectures, being persuaded that it was of the utmost importance that his pupils should be well grounded in the principles of chemistry. his health had never been robust, and as he grew old he was obliged to use great care in his diet; his simple and methodical character and habits made it easy for him to live on the plainest food, and to take meals and exercise at stated times and in fixed quantities. black's life closed, as was fitting, in a quiet and honoured old age. he had many friends, but lived pretty much alone--he was never married. on the th of november , "being at table with his usual fare, some bread, a few prunes and a measured quantity of milk diluted with water, and having the cup in his hand when the last stroke of his pulse was to be given, he had set it down on his knees, which were joined together, and kept it steady with his hand, in the manner of a person perfectly at ease; and in this attitude he expired, without spilling a drop, and without a writhe in his countenance, as if an experiment had been required to show to his friends the facility with which he departed." black was characterized by "moderation and sobriety of thought;" he had a great sense of the fitness of things--of what is called by the older writers "propriety." but he was by no means a dull companion; he enjoyed general society, and was able to bear a part in any kind of conversation. a thorough student of nature, he none the less did not wish to devote his whole time to laboratory work or to the labours of study; indeed he seems to have preferred the society of well-cultivated men and women to that of specialists in his own or other branches of natural science. but with his true scientific peers he doubtless appeared at his best. among his more intimate friends were the famous political economist adam smith, and the no less celebrated philosopher david hume. dr. hutton, one of the earliest workers in geology, was a particular friend of black; his friendship with james watt began when watt was a student in his class, and continued during his life. with such men as his friends, and engaged in the study of nature--that boundless subject which one can never know to the full, but which one can always know a little more year by year--black's life could not but be happy. his example and his teaching animated his students; he was what a university professor ought to be, a student among students, but yet a teacher among pupils. his work gained for him a place in the first rank of men of science; his clearness of mind, his moderation, his gentleness, his readiness to accept the views of others provided these views were well established on a basis of experimentally determined facts, fitted him to be the centre of a circle of scientific students who looked on him as at once their teacher and their friend. as a lecturer black was eminently successful. he endeavoured to make all his lectures plain and intelligible; he enlivened them by many experiments designed simply to illustrate the special point which he had in view. he abhorred ostentatious display and trickiness in a teacher. black was strongly opposed to the use of hypotheses in science. dr. robison (the editor of his lectures) tells that when a student in edinburgh he met black, who became interested in him from hearing him speak somewhat enthusiastically in favour of one of the lecturers in the university. black impressed on him the necessity of steady experimental work in natural science, gave him a copy of newton's "optics" as a model after which scientific work ought to be conducted, and advised him "to reject, even without examination, any hypothetical explanation, as a mere waste of time and ingenuity." but, when we examine black's own work, we see that by "hypothetical explanations" he meant vague guesses. he himself made free use of scientific (_i.e._ of exact) hypotheses; indeed the history of science tells us that without hypotheses advance is impossible. black taught by his own researches that science is not an array of facts, but that the object of the student of nature is to explain facts. but the method generally in vogue before the time of black was to gather together a few facts, or what seemed to be facts, and on these to raise a vast superstructure of "vain imaginings." naturalists had scarcely yet learned that nature is very complex, and that guessing and reasoning on guesses, with here and there an observation added, was not the method by which progress was to be made in learning the lessons written in this complex book of nature. in place of this loose and slipshod method black insisted that the student must endeavour to form a clear mental image of every phenomenon which he studied. such an image could be obtained only by beginning with detailed observation and experiment. from a number of definite mental images the student must put together a picture of the whole natural phenomenon under examination; perceiving that something was wanted here, or that the picture was overcrowded there, he must again go to nature and gain fresh facts, or sometimes prove that what had been accepted as facts had no real existence, and so at length he would arrive at a true representation of the whole process. so anxious was black to define clearly what he knew and professed to teach, that he preferred to call his lectures "on the effects of heat and mixtures," rather than to announce them as "a systematic course on chemistry." his introductory lecture on "heat in general" is very admirable; the following quotation will serve to show the clearness of his style and the methodical but yet eminently suggestive manner of his teaching:-- _"of heat in general._ "that this extensive subject may be treated in a profitable manner, i propose-- "first. to ascertain what i mean by the word _heat_ in these lectures. "secondly. to explain the meaning of the term _cold_, and ascertain the real difference between heat and cold. "thirdly. to mention some of the attempts which have been made to discover the nature of heat, or to form an idea of what may be the immediate cause of it. "fourthly and lastly. i shall begin to describe sensible effects produced by heat on the bodies to which it is communicated. "any person who reflects on the ideas which we annex to the word _heat_ will perceive that this word is used for two meanings, or to express two different things. it either means a sensation excited in our organs, or a certain quality, affection, or condition of the bodies around us, by which they excite in us that sensation. the word is used in the first sense when we say, we feel heat; in the second, when we say, there is heat in the fire or in a hot stone. there cannot be a sensation of heat in the fire, or in the hot stone, but the matter of the fire, or of the stone, is in a state or condition by which it excites in us the sensation of heat. "now, in beginning to treat of heat and its effects, i propose to use the word in this second sense only; or as expressing that state, condition, or quality of matter by which it excites in us the sensation of heat. this idea of heat will be modified a little and extended as we proceed, but the meaning of the word will continue at bottom the same, and the reason of the modification will be easily perceived." black's manner of dealing with the phenomenon of combustion illustrates the clearness of the conceptions which he formed of natural phenomena, and shows moreover the thoroughly unbiased nature of his mind. as soon as he had convinced himself that the balance of evidence was in favour of the new (antiphlogistic) theory, he gave up those doctrines in which he had been trained, and accepted the teaching of the french chemists; but he did not--as some with less well-balanced minds might do--regard the new theory as a final statement, but rather as one stage nearer the complete explanation which future experiments and future reasoning would serve to establish. in his lectures on combustion black first of all establishes the facts, that when a body is burned it is changed into a kind (or kinds) of matter which is no longer inflammable; that the presence of air is needed for combustion to proceed; that the substance must be heated "to a certain degree" before combustion or inflammation begins; that this degree of heat (or we should now say this degree of temperature) differs for each combustible substance; that the supply of air must be renewed if the burning is to continue; and that the process of burning produces a change in the quality of the air supplied to the burning body. he then states the phlogistic interpretation of these phenomena: that combustion is caused by the outrush from the burning body of a something called the _principle of fire_, or _phlogiston_. black then proceeds to demonstrate certain other facts:--when the substances produced by burning phosphorus or sulphur are heated with carbon (charcoal) the original phosphorus or sulphur is reproduced. this reproduction is due, according to the phlogistic chemists, to the giving back, by carbon, of the phlogiston which had escaped during the burning. hence carbon contains much phlogiston. but as a similar reproduction of phosphorus or sulphur, from the substances obtained by burning these bodies, can be accomplished by the use of substances other than carbon, it is evident that these other substances also contain much phlogiston, and, moreover, that the phlogiston contained in all these substances is one and the same _principle_. what then, he asks, is this "principle" which can so escape, and be so restored by the action of various substances? he then proceeds as follows:-- "but when we inquire further, and endeavour to learn what notion was formed of the nature of this principle, and what qualities it was supposed to have in its separate state, we find this part of the subject very obscure and unsatisfactory, and the opinions very unsettled. "the elder chemists, and the alchemists, considered sulphur as the universal inflammable principle, or at least they chose to call the inflammable part of all bodies, that are more or less inflammable, by the name of their sulphur.... the famous german chemist becher was, i believe, the first who rejected the notion of sulphur being the principle of inflammability in bodies.... his notion of the nature of the pure principle of inflammability was afterwards more fully explained and supported by professor stahl, who, agreeably to the doctrine of becher, represented the principle of inflammability as a dry substance, or of an earthy nature, the particles of which were exquisitely subtile, and were much disposed to be agitated and set in motion with inconceivable velocity.... the opinion of becher and stahl concerning this _terra secunda_, or _terra inflammabilis_, or _phlogiston_, was that the atoms of it are, more than all others, disposed to be affected with an excessively swift whirling motion (_motus vorticillaris_). the particles of other elementary substances are likewise liable to be affected with the same sort of motion, but not so liable as those of _terra secunda_; and when the particles of any body are agitated with this sort of motion, the body exhibits the phenomena of heat, or ignition, or inflammation according to the violence and rapidity of the motion.... becher and stahl, therefore, did not suppose that heat depended on the abundance of a peculiar matter, such as the matter of heat or fire is now supposed to be, but on a peculiar motion of the particles of matter.... "this very crude opinion of the earthy nature of the principle of inflammability appears to have been deduced from a quality of many of the inflammable substances, by which they resist the action of water as a solvent. the greater number of the earthy substances are little, or not at all, soluble in water.... and when becher and stahl found those compounds, which they supposed contained phlogiston in the largest quantity, to be insoluble in water, although the other matter, with which the phlogiston was supposed to be united, was, in its separate state, exceedingly soluble in that fluid, they concluded that _a dry nature, or an incapability to be combined with water_, was an eminent quality of their phlogiston; and this was what they meant by calling it an earth or earthy substance.... but these authors supposed, at the same time, that the particles of this dry and earthy phlogiston were much disposed to be excessively agitated with a whirling motion; which whirling motion, exerted in all directions from the bodies in which phlogiston is contained, produced the phenomena of inflammation. this appears to have been the notion formed by becher and stahl, concerning the nature of the principle of inflammability, or the phlogiston; a notion which seems the least entitled to the name of explanation of anything we can think of. i presume that few persons can form any clear conception of this whirling motion, or, if they can, are able to explain to themselves how it produces, or can produce, anything like the phenomena of heat or fire." black then gives a clear account of the experiments of priestley and lavoisier (see pp. , , and - ), which established the presence, in common air, of a peculiar kind of gas which is especially concerned in the processes of combustion; he emphasizes the fact that a substance increases in weight when it is burned; and he gives a simple and clear statement of that explanation of combustion which is now accepted by all, and which does not require that the existence of any principle of fire should be assumed. it is important to note that black clearly connects the _physical_ fact that heat is absorbed, or evolved, by a substance during combustion, with the _chemical_ changes which are brought about in the properties of the substance burned. he concludes with an admirable contrast between the phlogistic theory and the theory of lavoisier, which shows how wide, and at the same time how definite, his conceptions were. black never speaks contemptuously of a theory which he opposes. "according to this theory" (_i.e._ the theory of lavoisier), "the inflammable bodies, sulphur for example, or phosphorus, are simple substances. the acid into which they are changed by inflammation is a compound. the chemists, on the contrary" (_i.e._ the followers of stahl), "consider the inflammable bodies as compounds, and the uninflammable matter as more simple. in the common theory the heat and light are supposed to emanate from, or to be furnished by, the burning body. but, in mr. lavoisier's theory, both are held to be furnished by the air, of which they are held to be constituent parts, or ingredients, while in its state of fire-supporting air." black was not a brilliant discoverer, but an eminently sound and at the same time imaginative worker; whatever he did he did well, but he did not exhaust any field of inquiry. many of the facts established by him have served as the basis of important work done by those who came after him. the number of new facts added by black to the data of chemistry was not large; but by his lectures--which are original dissertations of the highest value--he did splendid service in advancing the science of chemistry. black possessed that which has generally distinguished great men of science, a marked honesty of character; and to this he added comprehensiveness of mental vision: he saw beyond the limits of the facts which formed the foundations of chemical science in his day. he was not a fact-collector, but a philosopher. * * * * * joseph priestley, the son of jonas priestley, "a maker and dresser of woollen cloth," was born at fieldhead, near leeds, in the year . his mother, who was the daughter of a farmer near wakefield, died when he was seven years old. from that time he was brought up by a sister of his father, who was possessed of considerable private means. priestley's surroundings in his young days were decidedly religious, and evidently gave a tone to his whole after life. we shall find that priestley's work as a man of science can scarcely be separated from his theological and metaphysical work. his cast of mind was decidedly metaphysical; he was altogether different from black, who, as we have seen, was a typical student of natural phenomena. the house of priestley's aunt was a resort for all the dissenting ministers of that part of the county. she herself was strictly calvinistic in her theological views, but not wholly illiberal. priestley's early schooling was chiefly devoted to learning languages; he acquired a fair knowledge of latin, a little greek, and somewhat later he learned the elements of hebrew. at one time he thought of going into trade, and therefore, as he tells us in his "memoirs," he acquired some knowledge of french, italian and high dutch. with the help of a friend, a dissenting minister, he learned something of geometry, mathematics and natural philosophy, and also got some smattering of the chaldee and syriac tongues. at the age of nineteen priestley went to an "academy" at daventry. the intellectual atmosphere here seems to have been suitable to the rapid development of priestley's mind. great freedom of discussion was allowed; even during the teachers' lectures the students were permitted "to ask whatever questions and to make whatever remarks" they pleased; and they did it, priestley says, "with the greatest, but without any offensive, freedom." the students were required to read and to give an account of the more important arguments for and against the questions discussed in the teachers' lectures. theological disputations appear to have been the favourite topics on which the students exercised their ingenuity among themselves. priestley tells us that he "saw reason to embrace what is generally called the heterodox side of almost every question." leaving this academy, priestley went, in , as assistant to the dissenting minister at needham, in suffolk. here he remained for three years, living on a salary of about £ a year, and getting more and more into bad odour because of his peculiar theological views. from needham he moved to nantwich, in cheshire, where he was more comfortable, and, having plenty of work to do, he had little time for abstruse speculations. school work engaged most of his time at nantwich; he also began to collect a few scientific instruments, such as an electrical machine and an air-pump. these he taught his scholars to use and to keep in good order. he gave lectures on natural phenomena, and encouraged his scholars to make experiments and sometimes to exhibit their experiments before their parents and friends. he thus extended the reputation of his school and implanted in his scholars a love of natural knowledge. in the year priestley removed to warrington, to act as tutor in a newly established academy, where he taught languages--a somewhat wide subject, as it included lectures on "the theory of languages," on "oratory and criticism," and on "the history, laws, and constitution of england." he says, "it was my province to teach elocution, and also logic and hebrew. the first of these i retained, but after a year or two i exchanged the two last articles with dr. aikin for the civil law, and one year i gave a course of lectures on anatomy." during his stay at warrington, which lasted until , priestley married a daughter of mr. isaac wilkinson, an ironmaster of wrexham, in wales. he describes his wife as "a woman of an excellent understanding much improved by reading, of great fortitude and strength of mind, and of a temper in the highest degree affectionate and generous, feeling strongly for others and little for herself, also greatly excelling in everything relating to household affairs." about this time priestley met dr. franklin more than once in london. his conversation seems to have incited priestley to a further study of natural philosophy. he began to examine electrical phenomena, and this led to his writing and publishing a "history of electricity," in the course of which he found it necessary to make new experiments. the publication of the results of these experiments brought him more into notice among scientific men, and led to his election as a fellow of the royal society, and to his obtaining the degree of ll.d. from the university of edinburgh. in the year priestley removed to leeds, where he spent six years as minister of millhill chapel. he was able to give freer expression to his theological views in leeds than could be done in smaller places, such as needham and nantwich. during this time he wrote and published many theological and metaphysical treatises. but, what is of more importance to us, he happened to live near a brewery. now, the accidental circumstances, as we call them, of priestley's life were frequently of the greatest importance in their effects on his scientific work. black had established the existence and leading properties of fixed air about twelve or thirteen years before the time when priestley came to live near the brewery in leeds. he had shown that this fixed air is produced during alcoholic fermentation. priestley knowing this used to collect the fixed air which came off from the vats in the neighbouring brewery, and amuse himself with observing its properties. but removing from this part of the town his supplies of fixed air were stopped. as however he had become interested in working with airs, he began to make fixed air for himself from chalk, and in order to collect this air he devised a very simple piece of apparatus which has played a most important part in the later development of the chemistry of gases, or pneumatic chemistry. priestley's _pneumatic trough_ is at this day to be found in every laboratory; it is extremely simple and extremely perfect. a dish of glass, or earthenware, or wood is partly filled with water; a shelf runs across the dish at a little distance beneath the surface of the water; a wide-mouthed bottle is filled with water and placed, mouth downwards, over a hole in this shelf. the gas which is to be collected in this bottle is generated in a suitable vessel, from which a piece of glass or metal tubing passes under the shelf and stops just where the hole is made. the gas which comes from the apparatus bubbles up into the bottle, drives out the water, and fills the bottle. when the bottle is full of gas, it is moved to one side along the shelf, and another bottle filled with water is put in its place. as the mouth of each bottle is under water there is no connection between the gas inside and the air outside the bottle; the gas may therefore be kept in the bottle until the experimenter wants it. (see fig. . which is reduced from the cut in priestley's "air.") [illustration: fig. .] priestley tells us that at this time he knew very little chemistry, but he thinks that this was a good thing, else he might not have been led to make so many new discoveries as he did afterwards make. experimenting with fixed air, he found that water could be caused to dissolve some of the gas. in he published a pamphlet on the method of impregnating water with fixed air; this solution of fixed air in water was employed medicinally, and from this time we date the manufacture of artificial mineral waters. the next six years of priestley's life ( - ) are very important in the history of chemistry; it was during these years that much of his best work on various airs was performed. during this time he lived as a kind of literary companion (nominally as librarian) with the earl of shelburne (afterwards marquis of lansdowne.) his wife and family--he had now three children--lived at calne, in wiltshire, near lord shelburne's seat of bowood. priestley spent most of the summer months with his family, and the greater part of each winter with lord shelburne at his london residence; during this time he also travelled in holland and germany, and visited paris in . in a paper published in november , priestley says that he examined a specimen of air which he had extracted from saltpetre above a year before this date. this air "had by some means or other become noxious, but," he supposed, "had been restored to its former wholesome state, so as to effervesce with nitrous air" (in modern language, to combine with nitric oxide) "and to admit a candle to burn in it, in consequence of agitation with water." he tells us, in his "observations on air" ( ), that at this time he was altogether in the dark as to the nature of this air obtained from saltpetre. in august , he was amusing himself by observing the action of heat on various substances--"without any particular view," he says, "except that of extracting air from a variety of substances by means of a burning lens in quicksilver, which was then a new process with me, and which i was very proud of"--when he obtained from _red precipitate_ (oxide of mercury) an air in which a candle burned with a "remarkably vigorous flame." the production of this peculiar air "surprised me more than i can well express;" "i was utterly at a loss how to account for it." at first he thought that the specimen of _red precipitate_ from which the air had been obtained was not a proper preparation, but getting fresh specimens of this salt, he found that they all yielded the same kind of air. having satisfied himself by experiment that this peculiar air had "all the properties of common air, only in much greater perfection," he gave to it the name of _dephlogisticated air_. later experiments taught him that the same air might be obtained from red lead, from manganese oxide, etc., by the action of heat, and from various other salts by the action of acids. priestley evidently regards the new "dephlogisticated air" simply as very pure ordinary air; indeed, he seems to look on all airs, or gases, as easily changeable one into the other. he always interprets his experimental results by the help of the theory of phlogiston. one would indeed think from priestley's papers that the existence of this substance phlogiston was an unquestioned and unquestionable fact. thus, he says in the preface to his "experiments on air:" "if any opinion in all the modern doctrine concerning air be well founded, it is certainly this, that nitrous air is highly charged with phlogiston, and that from this quality only it renders pure air noxious.... if i have completely ascertained anything at all relating to air it is this." priestley thought that "very pure air" would take away phlogiston from some metals without the help of heat or any acid, and thus cause these metals to rust. he therefore placed some clean iron nails in _dephlogisticated air_ standing over mercury; after three months he noticed that about one-tenth of the air in the vessel had disappeared, and he concluded, although no rust appeared, that the dephlogisticated air had as a fact withdrawn phlogiston from the iron nails. this is the kind of reasoning which black described to his pupils as "mere waste of time and ingenuity." the experiment with the nails was made in ; at this time, therefore, priestley had no conception as to what his _dephlogisticated air_ really was. trying a great many experiments, and finding that the new air was obtained by the action of acids on earthy substances, priestley was inclined to regard this air, and if this then all other airs, as made up of an acid (or acids) and an earthy substance. we now know how completely erroneous this conclusion was, but we must remember that in priestley's time chemical substances were generally regarded as of no very definite or fixed composition; that almost any substance, it was supposed, might be changed into almost any other; that no clear meaning was attached to the word "element;" and that few, if any, careful measurements of the quantities of different kinds of matter taking part in chemical actions had yet been made. but at the same time we cannot forget that the books of hooke and mayow had been published years before this time, and that twenty years before priestley began his work on airs, black had published his exact, scientific investigation on fixed air. although we may agree with priestley that, had he made himself acquainted with what others had done before he began his own experiments, he might not have made so many new discoveries as he did, yet one cannot but think that his discoveries, although fewer, would have been more accurate. we are told by priestley that, when he was in paris in , he exhibited the method of obtaining dephlogisticated air from _red precipitate_ to lavoisier and other french chemists. we shall see hereafter what important results to science followed from this visit to lavoisier. let us shortly review priestley's answer to the question, "what happens when a substance burns in air?" beginning to make chemical experiments when he had no knowledge of chemistry, and being an extremely rapid worker and thinker, he naturally adopted the prevalent theory, and as naturally interpreted the facts which he discovered in accordance with this theory. when a substance burns, phlogiston, it was said, rushes out of it. but why does rapid burning only take place in air? because, said priestley, air has a great affinity for phlogiston, and draws it out of the burning substance. what then becomes of this phlogiston? we next inquire. the answer is, obviously it remains in the air around the burning body, and this is proved by the fact that this air soon becomes incapable of supporting the process of burning, it becomes phlogisticated. now, if phlogisticated air cannot support combustion, the greater the quantity of phlogiston in air, the less will it support burning; but we know that if a substance is burnt in a closed tube containing air, the air which remains when the burning is quite finished at once extinguishes a lighted candle. priestley also proved that an air can be obtained by heating _red precipitate_, characterized by its power of supporting combustion with great vigour. what is this but common air completely deprived of phlogiston? it is dephlogisticated air. now, if common air draws phlogiston out of substances, surely this dephlogisticated air will even more readily do the same. that it really does this priestley thought he had proved by his experiment with clean iron nails (see p. ). water was regarded as a substance which, like air, readily combined with phlogiston; but priestley thought that a candle burned less vigorously in dephlogisticated air which had been shaken with water than in the same air before this treatment; hence he concluded that phlogiston had been taken from the water. after cavendish had discovered (or rather rediscovered) hydrogen, and had established the fact that this air is extremely inflammable, most chemists began to regard this gas as pure or nearly pure phlogiston, or, at least, as a substance very highly charged with phlogiston. "now," said priestley, "when a metal burns phlogiston rushes out of it; if i restore this phlogiston to the metallic calx, i shall convert it back into the metal." he then showed by experiment that when calx of iron is heated with hydrogen, the hydrogen disappears and the metal iron is produced. he seemed, therefore, to have a large experimental basis for his answer to the question, "what happens when a substance burns?" but at a later time it was proved that iron was also produced by heating the calx of iron with carbon. the antiphlogistic chemists regarded fixed air as composed of carbon and dephlogisticated air; the phlogisteans said it was a substance highly charged with phlogiston. the antiphlogistic school said that calx of iron is composed of iron and dephlogisticated air; the phlogisteans said it was iron deprived of its phlogiston. here was surely an opportunity for a crucial experiment: when calx of iron is heated with carbon, and iron is produced, there must either be a production of fixed air (which is a non-inflammable gas, and forms a white solid substance when brought into contact with limewater), or there must be an outrush of phlogiston from the carbon. the experiment was tried: a gas was produced which had no action on limewater and which was very inflammable; what could this be but phlogiston, already recognized by this very property of extreme inflammability? thus the phlogisteans appeared to triumph. but if we examine these experiments made by priestley with the light thrown on them by subsequent research, we find that they bear the interpretation which he put on them only because they were not accurate; thus, two gases are inflammable, but it by no means follows that these gases are one and the same. we must have more accurate knowledge of the properties of these gases. the air around a burning body, such as iron, after a time loses the power of supporting combustion; but this is merely a qualitative fact. accurately to trace the change in the properties of this air, it is absolutely necessary that exact measurements should be made; when this is done, we find that the volume of air diminishes during the combustion, that the burning body gains weight, and that this gain in weight is just equal to the loss in weight undergone by the air. when the inflammable gas produced by heating calx of iron with carbon was carefully and _quantitatively_ analyzed, it was found to consist of carbon and oxygen (dephlogisticated air), but to contain these substances in a proportion different from that in which they existed in fixed air. it was a new kind of air or gas; it was _not_ hydrogen. this account of priestley's experiments and conclusions regarding combustion shows how easy it is in natural science to interpret experimental results, especially when these results are not very accurate, in accordance with a favourite theory; and it also illustrates one of the lessons so emphatically taught by all scientific study, viz. the necessity of suspending one's judgment until accurate measurements have been made, and the great wisdom of then judging cautiously. about priestley left lord shelburne, and went as minister of a chapel to birmingham, where he remained until . during his stay in birmingham, priestley had a considerable amount of pecuniary help from his friends. he had from lord shelburne, according to an agreement made when he entered his service, an annuity of £ a year for life; some of his friends raised a sum of money annually for him, in order that he might be able to prosecute his researches without the necessity of taking pupils. during the ten years or so after he settled in birmingham, priestley did a great deal of chemical work, and made many discoveries, almost entirely in the field of pneumatic chemistry. besides the discovery of dephlogisticated air (or oxygen) which has been already described, priestley discovered and gave some account of the properties of _nitrous air_ (nitric acid), _vitriolic acid air_ (sulphur dioxide), _muriatic acid air_ (hydrochloric acid), and _alkaline air_ (ammonia), etc. in the course of his researches on the last-named air he showed, that when a succession of electric sparks is passed through this gas a great increase in the volume of the gas occurs. this fact was further examined at a later time by berthollet, who, by measuring the increase in volume undergone by a measured quantity of ammonia gas, and determining the nature of the gases produced by the passage of the electric sparks, proved that ammonia is a compound of hydrogen and nitrogen, and that three volumes of the former gas combine with one volume of the latter to produce two volumes of ammonia gas. priestley's experiments on "inflammable air"--or hydrogen--are important and interesting. the existence of this substance as a definite kind of air had been proved by the accurate researches of cavendish in . priestley drew attention to many actions in which this inflammable air is produced, chiefly to those which take place between acids and metals. he showed that inflammable air is not decomposed by electric sparks; but he thought that it was decomposed by long-continued heating in closed tubes made of lead-glass. priestley regarded inflammable air as an air containing much phlogiston. he found that tubes of lead-glass, filled with this air, were blackened when strongly heated for a long time, and he explained this by saying that the lead in the glass had a great affinity for phlogiston, and drew it out of the inflammable air. when inflammable air burns in a closed vessel containing common air, the latter after a time loses its property of supporting combustion. priestley gave what appeared to be a fairly good explanation of this fact, when he said that the inflammable air parted with phlogiston, which, becoming mixed with the ordinary air in the vessel, rendered it unable to support the burning of a candle. he gave a few measurements in support of this explanation; but we now know that the method of analysis which he employed was quite untrustworthy. thinking that by measuring the extent to which the _phlogistication_ (we would now say the _deoxidation_) of common air was carried by mixing measured quantities of common and inflammable airs and exploding this mixture, he might be able to determine the amount of phlogiston in a given volume of inflammable air, he mixed the two airs in glass tubes, through the sides of which he had cemented two pieces of wire, sealed the tubes, and exploded the mixture by passing electric sparks from wire to wire. the residual air now contained, according to priestley, more phlogiston, and therefore relatively less dephlogisticated air than before the explosion. he made various measurements of the quantities of dephlogisticated air in the tubes, but without getting any constant results. he noticed that after the explosions the insides of the tubes were covered with moisture. at a later time he exploded a mixture of dephlogisticated and inflammable airs (oxygen and hydrogen) in a copper globe, and recorded the fact that after the explosion the globe contained a little water. priestley was here apparently on the eve of a great discovery. "in looking for one thing," says priestley, "i have generally found another, and sometimes a thing of much more value than that which i was in quest of." had he performed the experiment of exploding dephlogisticated and inflammable airs with more care, and had he made sure that the airs used were quite dry before the explosion, he would probably have found a thing of indeed much more value than that of which he was in quest; he would probably have discovered the compound nature of water--a discovery which was made by cavendish three or four years after these experiments described by priestley. some very curious observations were made by priestley regarding the colour of the gas obtained by heating "spirit of nitre" (_i.e._ nitric acid). he showed that a yellow gas or air is obtained by heating colourless liquid spirit of nitre in a sealed glass tube, and that as the heating is continued the colour of the gas gets darker, until it is finally very dark orange red. these experiments have found an explanation only in quite recent times. another discovery made by priestley while in birmingham, viz. that an acid is formed when electric sparks are passed through ordinary air for some time, led, in the hands of cavendish--an experimenter who was as careful and deliberate as priestley was rapid and careless--to the demonstration of the composition of nitric acid. many observations were made by priestley on the effects of various airs on growing plants and living animals; indeed, one of his customary methods of testing different airs was to put a mouse into each and watch the effects of the air on its breathing. he grew sprigs of mint in common air, in dephlogisticated air (oxygen), and in phlogisticated air (nitrogen, but probably not pure); the sprig in the last-named air grew best, while that in the dephlogisticated air soon appeared sickly. he also showed that air which has been rendered "noxious" by the burning of a candle in it, or by respiration or putrefaction, could be restored to its original state by the action of growing plants. he thought that the air was in the first instance rendered noxious by being impregnated with phlogiston, and that the plant restored the air by removing this phlogiston. thus priestley distinctly showed that (to use his own words) "it is very probable that the injury which is continually done to the atmosphere by the respiration of such a number of animals as breathe it, and the putrefaction of such vast masses, both of vegetable and animal substances, exposed to it, is, in part at least, repaired by the vegetable creation." but from want of quantitative experiments he failed to give any just explanation of the process whereby this "reparation" is accomplished. during his stay in birmingham, priestley was busily engaged, as was his wont during life, in writing metaphysical and theological treatises and pamphlets. at this time the minds of men in england were much excited by the events of the french revolution, then being enacted before them. priestley and some of his friends were known to sympathize with the french people in this great struggle, as they had been on the side of the americans in the war of independence. priestley's political opinions had, in fact, always been more advanced than the average opinion of his age; by some he was regarded as a dangerous character. but if we read what he lays down as a fundamental proposition in the "essay on the first principles of civil government" ( ), we cannot surely find anything very startling. "it must be understood, whether it be expressed or not, that all people live in society for their mutual advantage; so that the good and happiness of the members, that is the majority of the members of any state, is the great standard by which everything relating to that state must be finally determined. and though it may be supposed that a body of people may be bound by a voluntary resignation of all their rights to a single person, or to a few, it can never be supposed that the resignation is obligatory on their posterity, because it is manifestly contrary to the good of the whole that it should be so." priestley proposed many political reforms, but he was decidedly of opinion that these ought to be brought about gradually. he was in favour of abolishing all religious state establishments, and was a declared enemy to the church of england. his controversies with the clergy of birmingham helped to stir up a section of public opinion against him, and to bring about the condemnation of his writings in many parts of the country; he was also unfortunate in making an enemy of mr. burke, who spoke against him and his writings in the house of commons. in the year , the day of the anniversary of the taking of the bastille was celebrated by some of priestley's friends in birmingham. on that day a senseless mob, raising the cry of "church and king," caused a riot in the town. finding that they were not checked by those in authority, they after a time attacked and burned dr. priestley's meeting-house, and then destroyed his dwelling-house, and the houses of several other dissenters in the town. one of his sons barely escaped with his life. he himself found it necessary to leave birmingham for london, as he considered his life to be in danger. many of his manuscripts, his library, and much of his apparatus were destroyed, and his house was burned. a congregation at hackney had the courage at this time to invite priestley to become their minister. here he remained for about three years, ministering to the congregation, and pursuing his chemical and other experiments with the help of apparatus and books which had been supplied by his friends, and by the expenditure of part of the sum, too small to cover his losses, given him by government in consideration of the damage done to his property in the riots at birmingham. but finding himself more and more isolated and lonely, especially after the departure of his three sons to america, which occurred during these years, he at last resolved to follow them, and spend the remainder of his days in the new world. although priestley had been very badly treated by a considerable section of the english people, yet he left his native country "without any resentment or ill will." "when the time for reflection," he says, "shall come, my countrymen will, i am confident, do me more justice." he left england in , and settled at northumberland, in pennsylvania, about a hundred and thirty miles north-west of philadelphia. by the help of his friends in england he was enabled to build a house and establish a laboratory and a library; an income was also secured sufficient to maintain him in moderate comfort. the chair of chemistry in the university of philadelphia was offered to him, and he was also invited to the charge of a unitarian chapel in new york; but he preferred to remain quietly at work in his laboratory and library, rather than again to enter into the noisy battle of life. in america he published several writings. of his chemical discoveries made after leaving england, the most important was that an inflammable gas is obtained by heating metallic calces with carbon. the production of this gas was regarded by priestley as an indisputable proof of the justness of the theory of phlogiston (see pp. , ). his health began to give way about ; gradually his strength declined, and in february , the end came quietly and peacefully. a list of the books and pamphlets published by priestley on theological, metaphysical, philological, historical, educational and scientific subjects would fill several pages of this book. his industry was immense. to accomplish the vast amount of work which he did required the most careful outlay of time. in his "memoirs," partly written by himself, he tells us that he inherited from his parents "a happy temperament of body and mind;" his father especially was always in good spirits, and "could have been happy in a workhouse." his paternal ancestors had, as a race, been healthy and long-lived. he was not himself robust as a youth, yet he was always able to study: "i have never found myself," he says, "less disposed or less qualified for mental exertion of any kind at one time of the day more than another; but all seasons have been equal to me, early or late, before dinner or after." his peculiar evenness of disposition enabled him quickly to recover from the effects of any unpleasant occurrence; indeed, he assures us that "the most perfect satisfaction" often came a day or two after "an event that afflicted me the most, and without any change having taken place in the state of things." another circumstance which tended to make life easy to him was his fixed resolution, that in any controversy in which he might be engaged, he would frankly acknowledge every mistake he perceived himself to have fallen into. priestley's scientific work is marked by rapidity of execution. the different parts do not hang together well; we are presented with a brilliant series of discoveries, but we do not see the connecting strings of thought. we are not then astonished when he tells us that sometimes he forgot that he had made this or that experiment, and repeated what he had done weeks before. he says that he could not work in a hurry, and that he was therefore always methodical; but he adds that he sometimes blamed himself for "doing to-day what had better have been put off until to-morrow." many of his most startling discoveries were the results of chance operations, "not of themes worked out and applied." he was led to the discovery of oxygen, he says, by a succession of extraordinary accidents. but that he was able to take advantage of the chance observations, and from these to advance to definite facts, constitutes the essential difference between him and ordinary plodding investigators. although he rarely, if ever, saw all the bearings of his own discoveries, although none of his experiments was accurately worked out to its conclusion, yet he did see, rapidly and as it appeared almost at one glance, something of their meanings, and this something was enough to urge him on to fresh experimental work. although we now condemn priestley's theories as quite erroneous, yet we must admire his undaunted devotion to experiment. he was a true student of science in one essential point, viz. nature was for him the first and the last court of appeal. he theorized and speculated much, he experimented rapidly and not accurately, but he was ever appealing to natural facts; and in doing this he could not but lay some foundation which should remain. the facts discovered by him are amongst the very corner-stones on which the building of chemical science was afterwards raised. so enthusiastic was priestley in the prosecution of his experiments, that when he began, he tells us, "i spent all the money i could possibly raise, carried on by my ardour in philosophical investigation, and entirely regardless of consequences, except so far as never to contract any debts." he seems all through his life to have been perfectly free from anxiety about money affairs. priestley's manner of work shows how kindly and genial he was. he trained himself to talk and think and write with his family by the fireside; "nothing but reading aloud, or speaking without interruption," was an obstruction to his work. priestley was just the man who was wanted in the early days of chemical science. by the vast number, variety and novelty of his experimental results, he astonished scientific men--he forcibly drew attention to the science in which he laboured so hard; by the brilliancy of some of his experiments he obliged chemists to admit that a new field of research was opened before them, and the instruments for the prosecution of this research were placed in their hands; and even by the unsatisfactoriness of his reasoning he drew attention to the difficulties and contradictions of the theories which then prevailed in chemistry. that the work of priestley should bear full fruit it was necessary that a greater than he should interpret it, and should render definite that which priestley had but vaguely shown to exist. the man who did this, and who in doing it really established chemistry as a science, was lavoisier. but before considering the work of lavoisier, i should like to point out that many of the physical characters of common air had been clearly established in the later years of the seventeenth century by the honourable robert boyle. in the "sceptical chymist," published in , mr. boyle had established the fact that air is a material substance possessed of weight, that this air presses on the surface of all things, and that by removing part of the air in an enclosed space the pressure within that space is diminished. he had demonstrated that the boiling point of water is dependent on the pressure of the air on the surface of the water. having boiled some water "a pretty while, that by the heat it might be freed from the latitant air," he placed the vessel containing the hot water within the receiver of an arrangement which he had invented for sucking air out of an enclosed space; as soon as he began to suck out air from this receiver, the water boiled "as if it had stood over a very quick fire.... once, when the air had been drawn out, the liquor did, upon a single exsuction, boil so long with prodigiously vast bubbles, that the effervescence lasted almost as long as was requisite for the rehearsing of a _pater noster_." boyle had gone further than the qualitative fact that the volume of an enclosed quantity of air alters with changes in the pressure to which that air is subjected; he had shown by simple and accurate experiments that "the volume varies inversely as the pressure." he had established the generalization of so much importance in physical science now known as _boyle's law_. the work of the honourable henry cavendish will be considered in some detail in the book on "the physicists" belonging to this series, but i must here briefly allude to the results of his experiments on air published in the _philosophical transactions_ for and . cavendish held the ordinary view that when a metal burns in air, the air is thereby phlogisticated; but why is it, he asked, that the volume of air is decreased by this process? it was very generally said that fixed air was produced during the calcination of metals, and was absorbed by the calx. but cavendish instituted a series of experiments which proved that no fixed air could be obtained from metallic calces. in inflammable air (hydrogen) was discovered by cavendish; he now proved that when this air is exploded with dephlogisticated air (oxygen), water is produced. he showed that when these two airs are mixed in about the proportion of two volumes of hydrogen to one volume of oxygen, the greater part, if not the whole of the airs is condensed into water by the action of the electric spark. he then proceeded to prove by experiments that when common air is exploded with inflammable air water is likewise produced, and phlogisticated air (_i.e._ nitrogen) remains. priestley and cavendish had thus distinctly established the existence of three kinds of air, viz. dephlogisticated air, phlogisticated air, and inflammable air. cavendish had shown that when the last named is exploded with common air water is produced (which is composed of dephlogisticated and inflammable airs), and phlogisticated air remains. common air had thus been proved to consist of these two--phlogisticated and dephlogisticated airs (nitrogen and oxygen). applying these results to the phenomenon of the calcination of metals, cavendish gave reasons for thinking that the metals act towards common air in a manner analogous to that in which inflammable air acts--that they withdraw dephlogisticated and leave phlogisticated air; but, as he was a supporter of the phlogistic theory, he rather preferred to say that the burning metals withdraw dephlogisticated air and phlogisticate that which remains; in other words, while admitting that a metal in the process of burning gains dephlogisticated air, he still thought that the metal also loses _something_; viz. phlogiston. that cavendish in - had proved air to consist of two distinct gases, and water to be produced by the union of two gases, must be remembered as we proceed with the story of the discoveries of lavoisier. * * * * * antoine laurent lavoisier, born in paris in , was the son of a wealthy merchant, who, judging from his friendship with many of the men of science of that day, was probably of a scientific bent of mind, and who certainly showed that he was a man of sense by giving his son the best education which he could obtain. after studying in the mazarin college, lavoisier entered on a course of training in physical, astronomical, botanical and chemical science. the effects of this training in the accurate methods of physics are apparent in the chemical researches of lavoisier. at the age of twenty-one lavoisier wrote a memoir which gained the prize offered by the french government for the best and most economical method of lighting the streets of a large city. while making experiments, the results of which were detailed in this paper, lavoisier lived for six weeks in rooms lighted only by artificial light, in order that his eyesight might become accustomed to small differences in the intensities of light from various sources. when he was twenty-five years old lavoisier was elected a member of the academy of sciences. during the next six years ( - ) he published various papers, some on chemical, some on geological, and some on mathematical subjects. indeed at this time, although an ardent cultivator of natural science, he appears to have been undecided as to which branch of science he should devote his strength. the accuracy and thoroughness of lavoisier's work, and the acuteness of his reasoning powers, are admirably illustrated in two papers, published in the memoirs of the academy for , on the alleged conversion of water into earth. when water is boiled for a long time in a glass vessel a considerable quantity of white siliceous earth is found in the vessel. this apparent conversion or transmutation of water into earthy matter was quite in keeping with the doctrines which had been handed down from the times of the alchemists; the experiment was generally regarded as conclusively proving the possibility of changing water into earth. lavoisier found that after heating water for a hundred and one days in a closed _and weighed_ glass vessel, there was no change in the total weight of the vessel and its contents; when he poured out the water and evaporated it to dryness, he obtained . grains of solid earthy matter; but he also found, what had been before overlooked, that the glass vessel had lost weight. the actual loss amounted to . grains. the difference between this and the weight of the earthy matter in the water, viz. three grains, was set down (and as we now know justly set down) by lavoisier to errors of experiment. lavoisier therefore concluded that water, when boiled, is not changed into earth, but that a portion of the earthy matter of which glass is composed is dissolved by the water. this conclusion was afterwards confirmed by the swedish chemist _scheele_, who proved that the composition of the earthy matter found in the water is identical with that of some of the constituents of glass. by this experiment lavoisier proved the old alchemical notion of transmutation to be erroneous; he showed that water is not transmuted into earth, but that each of these substances is possessed of definite properties which belong to it and to it only. he established the all-important generalization--which subsequent research has more amply confirmed, until it is to-day accepted as the very foundation of every branch of physical science--that in no process of change is there any alteration in the total mass of matter taking part in that change. the glass vessel in which lavoisier boiled water for so many days lost weight; but the matter lost by the glass was found dissolved in the water. we know that this generalization holds good in all chemical changes. solid sulphur may be converted into liquid oil of vitriol, but it is only by the sulphur combining with other kinds of matter; the weight of oil of vitriol produced is always exactly equal to the sum of the weights of the sulphur, hydrogen and oxygen which have combined to form it. the colourless gases, hydrogen and oxygen, combine, and the limpid liquid water is the result; but the weight of the water produced is equal to the sum of the weights of hydrogen and oxygen which combined together. it is impossible to overrate the importance of the principle of the _conservation of mass_, first definitely established by lavoisier. some time about the year lavoisier turned his attention seriously to chemical phenomena. in he published a volume entitled "essays physical and chemical," wherein he gave an historical account of all that had been done on the subject of airs from the time of paracelsus to the year , and added an account of his own experiments, in which he had established the facts that a metal in burning absorbs air, and that when the metallic calx is reduced to metal by heating with charcoal, an air is produced of the same nature as the fixed air of dr. black. in november lavoisier deposited a sealed note in the hands of the secretary to the academy of sciences. this note was opened on the st of may , and found to run as follows[ ]:-- "about eight days ago i discovered that sulphur in burning, far from losing, augments in weight; that is to say, that from one pound of sulphur much more than one pound of vitriolic acid is obtained, without reckoning the humidity of the air. phosphorus presents the same phenomenon. this augmentation of weight arises from a great quantity of air which becomes fixed during the combustion, and which combines with the vapours. "this discovery, confirmed by experiments which i regard as decisive, led me to think that what is observed in the combustion of sulphur and phosphorus might likewise take place with respect to all the bodies which augment in weight by combustion and calcination; and i was persuaded that the augmentation of weight in the calces of metals proceeded from the same cause. the experiment fully confirmed my conjectures. "i operated the reduction of litharge in closed vessels with hale's apparatus, and i observed that at the moment of the passage of the calx into the metallic state, there was a disengagement of air in considerable quantity, and that this air formed a volume at least one thousand times greater than that of the litharge employed. "as this discovery appears to me one of the most interesting which has been made since stahl, i thought it expedient to secure to myself the property, by depositing the present note in the hands of the secretary of the academy, to remain secret till the period when i shall publish my experiments. "lavoisier. "paris, th november ." in his paper "on the calcination of tin in closed vessels, and on the cause of increase of weight acquired by the metal during this process" (published in ), we see and admire lavoisier's manner of working. a weighed quantity (about half a pound) of tin was heated to melting in a glass retort, the beak of which was drawn out to a very small opening; the air within the retort having expanded, the opening was closed by melting the glass before the blowpipe. the weight of retort and tin was now noted; the tin was again heated to its melting point, and kept at this temperature as long as the process of calcination appeared to proceed; the retort and its contents were then allowed to cool and again weighed. no change was caused by the heating process in the total weight of the whole apparatus. the end of the retort beak was now broken off; air rushed in with a hissing sound. the retort and contents were again weighed, and the increase over the weight at the moment of sealing the retort was noted. the calcined tin in the retort was now collected and weighed. it was found that the increase in the weight of the tin was equal to the weight of the air which rushed into the retort. hence lavoisier concluded that the calcination of tin was accompanied by an absorption of air, and that the difference between the weights of the tin and the calx of tin was equal to the weight of air absorbed; but he states that probably only a part of the air had combined with the tin, and that hence air is not a simple substance, but is composed of two or more constituents. between the date of this publication and that of lavoisier's next paper on combustion we know that priestley visited paris. in his last work, "the doctrine of phlogiston established" (published in ), priestley says, "having made the discovery of dephlogisticated air some time before i was in paris in , i mentioned it at the table of mr. lavoisier, when most of the philosophical people in the city were present; saying that it was a kind of air in which a candle burned much better than in common air, but i had not then given it any name. at this all the company, and mr. and mrs. lavoisier as much as any, expressed great surprise. i told them that i had got it from _precipitatum per se_, and also from _red lead_." in lavoisier's paper, "on the nature of the principle which combines with the metals during their calcination, and which augments their weight," was read before the academy. the preparation and properties of an air obtained, in november , from _red precipitate_ are described, but priestley's name is not mentioned. it seems probable, however, that lavoisier learned the existence and the mode of preparation of this air from priestley;[ ] but we have seen that even in priestley was quite in the dark as to the true nature of the air discovered by him (p. ). in papers published in the next three or four years lavoisier gradually defined and more thoroughly explained the phenomenon of combustion. he burned phosphorus in a confined volume of air, and found that about one-fourth of the air disappeared, that the residual portion of air was unable to support combustion or to sustain animal life, that the phosphorus was converted into a white substance deposited on the sides of the vessel in which the experiment was performed, and that for each grain of phosphorus used about two and a half grains of this white solid were obtained. he further described the properties of the substance produced by burning phosphorus, gave it the name of _phosphoric acid_, and described some of the substances formed by combining it with various bases. the burning of candles in air was about this time studied by lavoisier. he regarded his experiments as proving that the air which remained after burning a candle, and in which animal life could not be sustained, was really present before the burning; that common air consisted of about one-fourth part of dephlogisticated air and three-fourths of _azotic air_ (_i.e._ air incapable of sustaining life); and that the burning candle simply combined with, and so removed the former of these, and at the same time produced more or less fixed air. in his treatise on chemistry lavoisier describes more fully his proof that the calcination of a metal consists in the removal, by the metal, of dephlogisticated air (or oxygen) from the atmosphere, and that the metallic calx is simply a compound of metal and oxygen. the experiments are strictly quantitative and are thoroughly conclusive. he placed four ounces of pure mercury in a glass balloon, the neck of which dipped beneath the surface of mercury in a glass dish, and then passed a little way up into a jar containing fifty cubic inches of air, and standing in the mercury in the dish. there was thus free communication between the air in the balloon and that in the glass jar, but no communication between the air inside and that outside the whole apparatus. the mercury in the balloon was heated nearly to its boiling point for twelve days, during which time red-coloured specks gradually formed on the surface of the metal; at the end of this time it was found that the air in the glass jar measured between forty-two and forty-three cubic inches. the red specks when collected amounted to forty-five grains; they were heated in a very small retort connected with a graduated glass cylinder containing mercury. between seven and eight cubic inches of pure dephlogisticated air (oxygen) were obtained in this cylinder, and forty-one and a half grains of metallic mercury remained when the decomposition of the red substance was completed. the conclusion drawn by lavoisier from these experiments was that mercury, when heated nearly to boiling in contact with air, withdraws oxygen from the air and combines with this gas to form _red precipitate_, and that when the red precipitate which has been thus formed is strongly heated, it parts with the whole of its oxygen, and is changed back again into metallic mercury. lavoisier had now ( - ) proved that the calces of mercury, tin and lead are compounds of these metals with oxygen; and that the oxygen is obtained from the atmosphere when the metal burns. but the phlogistic chemistry was not yet overthrown. we have seen that the upholders of phlogiston believed that in the inflammable air of cavendish they had at last succeeded in obtaining the long-sought-for phlogiston. now they triumphantly asked, why, when metals dissolve in diluted vitriolic or muriatic acid with evolution of inflammable air, are calces of these metals produced? and they answered as triumphantly, because these metals lose phlogiston by this process, and we know that a calx is a metal deprived of its phlogiston. lavoisier contented himself with observing that a metallic calx always weighed more than the metal from which it was produced; and that as inflammable air, although much lighter than common air, was distinctly possessed of weight, it was not possible that a metallic calx could be metal deprived of inflammable air. he had given a simple explanation of the process of calcination, and had proved, by accurate experiments, that this explanation was certainly true in some cases. although all the known facts about solution of metals in acids could not as yet be brought within his explanation, yet none of these facts was absolutely contradictory of that explanation. he was content to wait for further knowledge. and to gain this further knowledge he set about devising and performing new experiments. the upholders of the theory of phlogiston laid considerable stress on the fact that metals are produced by heating metallic calces in inflammable air; the air is absorbed, they said, and so the metal is reproduced. it was obviously of the utmost importance that lavoisier should learn more about this inflammable air, and especially that he should know exactly what happened when this air was burned. he therefore prepared to burn a large quantity of inflammable air, arranging the experiment so that he should be able to collect and examine the product of this burning, whatever should be the nature of that product. but at this time the news was brought to paris that cavendish had obtained water by burning mixtures of inflammable and dephlogisticated airs. this must have been a most exciting announcement to lavoisier; he saw how much depended on the accuracy of this statement, and as a true student of nature, he at once set about to prove or disprove it. on the th of june , in the presence of the king and several notabilities (including sir charles blagden, secretary of the royal society, who had told lavoisier of the experiments of cavendish), lavoisier and laplace burned inflammable and dephlogisticated airs, and obtained water. as the result of these experiments they determined that one volume of dephlogisticated air combines with . volumes of inflammable air to form water. a little later lavoisier completed the proof of the composition of water by showing that when steam is passed through a tube containing iron filings kept red hot, inflammable air is evolved and calx of iron remains in the tube. lavoisier could now explain the conversion of a metallic calx into metal by the action of inflammable air; this air decomposes the calx--that is, the metallic oxide--combines with its oxygen to form water, and so the metal is produced. when a metal is dissolved in diluted vitriolic or muriatic acid a calx is formed, because, according to lavoisier, the water present is decomposed by the metal, inflammable air is evolved, and the dephlogisticated air of the water combines with the metal forming a calx, which then dissolves in the acid. lavoisier now studied the properties of the compounds produced by burning phosphorus, sulphur and carbon in dephlogisticated air. he found that solutions of these compounds in water had a more or less sour taste and turned certain blue colouring matters red; but these were the properties regarded as especially belonging to acids. these products of combustion in dephlogisticated air were therefore acids; but as phosphorus, carbon and sulphur were not themselves acids, the acid character of the substances obtained by burning these bodies in dephlogisticated air must be due to the presence in them of this air. hence lavoisier concluded that this air is the substance the presence of which in a compound confers acid properties on that compound. this view of the action of dephlogisticated air he perpetuated in the name "oxygen" (from greek, = _acid-producer_), which he gave to dephlogisticated air, and by which name this gas has ever since been known. priestley was of opinion that the atmosphere is rendered noxious by the breathing of animals, because it is thereby much phlogisticated, and he thought that his experiments rendered it very probable that plants are able to purify this noxious air by taking away phlogiston from it (see p. ). but lavoisier was now able to give a much more definite account of the effects on the atmosphere of animal and vegetable life. he had already shown that ordinary air contains oxygen and azote (nitrogen), and that the former is alone concerned in the process of combustion. he was now able to show that animals during respiration draw in air into their lungs: that a portion of the oxygen is there combined with carbon to form carbonic acid gas (as the fixed air of black was now generally called), which is again expired along with unaltered azote. respiration was thus proved to be a process chemically analogous to that of calcination. thus, about the year - , the theory of phlogiston appeared to be quite overthrown. the arguments of its upholders, after this time, were not founded on facts; they consisted of fanciful interpretations of crudely performed experiments. cavendish was the only opponent to be dreaded by the supporters of the new chemistry. but we have seen that although cavendish retained the language of the phlogistic theory (see pp. , ) as in his opinion equally applicable to the facts of combustion with that of the new or lavoisierian theory, he nevertheless practically admitted the essential point of the latter, viz. that calces are compounds of metal and oxygen (or dephlogisticated air). although cavendish was the first to show that water is produced when the two gases hydrogen and oxygen are exploded together, it would yet appear that he did not fully grasp the fact that water is a compound of these two gases; it was left to lavoisier to give a clear statement of this all-important fact, and thus to remove the last prop from under the now tottering, but once stately edifice built by stahl and his successors. the explanation given by lavoisier of combustion was to a great extent based on a conception of element and compound very different from that of the older chemists. in the "sceptical chymist" ( ) boyle had argued strongly against the doctrine of the four "elementary principles," earth, air, fire and water, as held by the "vulgar chymists." the existence of these principles, or some of them, in every compound substance was firmly held by most chemists in boyle's time. they argued thus: when a piece of green wood bums, the existence in the wood of the principle of fire is made evident by the flame, of the principle of air by the smoke which ascends, of that of water by the hissing and boiling sound, and of the principle of earth by the ashes which remain when the burning is finished.[ ] boyle combated the inference that because a flame is visible round the burning wood, and a light air or smoke ascends from it, _therefore_ these principles were contained in the wood before combustion began. he tried to prove by experiments that one substance may be obtained from another in which the first substance did not already exist; thus, he heated water for a year in a closed glass vessel, and obtained solid particles heavier than, and as he supposed formed from, the water. we have already learned the true interpretation of this experiment from the work of lavoisier. boyle grew various vegetables in water only, and thought that he had thus changed water into solid vegetable matter. he tells travellers' tales of the growth of pieces of iron and other metals in the earth or while kept in underground cellars. we now know how erroneous in most points this reasoning was, but we must admit that boyle established one point most satisfactorily, viz. that because earth, or air, or fire, or water is obtained by heating or otherwise decomposing a substance, it does not necessarily follow that the earth, or air, or fire, or water existed as such in the original substance. he overthrew the doctrine of elementary principles held by the "vulgar chymists." defining elements as "certain primitive and simple bodies which, not being made of any other bodies, or of one another, are the ingredients of which all those called perfectly mixt bodies are immediately compounded, and into which they are ultimately resolved," boyle admitted the _possible_ existence, but thought that the facts known at his time did not warrant the assertion of the _certain_ existence, of such "elements." the work of hooke and mayow on combustion tended to strengthen this definition of "element" given by boyle. black, as we have seen, clearly proved that certain chemical substances were possessed of definite and unvarying composition and properties; and lavoisier, indirectly by his explanation of combustion, and directly in his "treatise on chemistry", laid down the definition of "element" which is now universally adopted. an element is a substance from which no simpler forms of matter--that is, no forms of matter each weighing less than the original substance--have _as yet_ been obtained. in the decade - chemical science was thus established on a sure foundation by lavoisier. like most great builders, whether of physical or mental structures, he used the materials gathered by those who came before him, but the merit of arranging these materials into a well-laid foundation, on which the future building might firmly rest, is due to him alone. the value of lavoisier's work now began to be recognized by his fellow-chemists in france. in berthollet, one of the most rising of the younger french chemists, declared himself a convert to the views of lavoisier on combustion. fourcroy, another member of the academy, soon followed the example of berthollet. fourcroy, knowing the weakness of his countrymen, saw that if the new views could be made to appear as especially the views of frenchmen, the victory would be won; he therefore gave to the theory of lavoisier the name "_la chimie française_". although this name was obviously unfair to lavoisier, it nevertheless caused the antiphlogistic theory to be identified with the french chemists, and succeeded in impressing the french public generally with the idea that to hold to the old theory was to be a traitor to the glory of one's country. m. de morveau, who held a prominent place both in politics and science, was invited to paris, and before long was persuaded to embrace the new theory. this conversion--for "the whole matter was managed as if it had been a political intrigue rather than a philosophical inquiry"--was of great importance to lavoisier and his friends. m. de morveau was editor of the chemical part of the "encyclopédie méthodique;" in that part of this work which had appeared before de morveau had skilfully opposed the opinions of lavoisier, but in the second part of the work he introduced an advertisement announcing the change in his opinions on the subject of combustion, and giving his reasons for this change. the importance of having a definite language in every science is apparent at each step of advance. lavoisier found great difficulty in making his opinions clear because he was obliged to use a language which had been introduced by the phlogistic chemists, and which bore the impress of that theory on most of its terms. about the years - , lavoisier, berthollet, fourcroy and de morveau drew up a new system of chemical nomenclature. the fundamental principles of that system have remained as those of every nomenclature since proposed. they are briefly these:-- an element is a substance from which no form of matter simpler than itself has as yet been obtained. every substance is to be regarded as an element until it is proved to be otherwise. the name of every compound is to tell of what elements the substance is composed, and it is to express as far as possible the relative amounts of the elements which go to form the compound. thus the compounds of oxygen with any other element were called oxides, _e.g._ iron oxide, mercury oxide, tin oxide, etc. when two oxides of iron came to be known, one containing more oxygen relatively to the amount of iron present than the other, that with the greater quantity of oxygen was called iron peroxide, and that with the smaller quantity iron protoxide. we now generally prefer to use the name of the element other than oxygen in adjectival form, and to indicate the relatively smaller or greater quantity of oxygen present by modifications in the termination of this adjective. thus iron protoxide is now generally known as ferr_ous_ oxide, and iron peroxide as ferr_ic_ oxide. but the principles laid down by the four french chemists in - remain as the groundwork of our present system of nomenclature. the antiphlogistic theory was soon adopted by all french chemists of note. we have already seen that black, with his usual candour and openness to conviction, adopted and taught this theory, and we are assured by dr. thomas thomson that when he attended black's classes, nine years after the publication of the french system of nomenclature, that system was in general use among the chemical students of the university. the older theory was naturally upheld by the countrymen of the distinguished stahl after it had been given up in france. in the year klaproth, who was then professor of chemistry in berlin, proposed to the berlin academy of sciences to repeat the more important experiments on which the lavoisierian theory rested, before the academy. his offer was accepted, and from that time most of the berlin chemists declared themselves in favour of the new theory. by the close of last century the teaching of lavoisier regarding combustion found almost universal assent among chemists. but this teaching carried with it, as necessary parts, the fundamental distinction between element and compound; the denial of the existence of "principles" or "essences;" the recognition of the study of actually occurring reactions between substances as the basis on which all true chemical knowledge was to be built; and the full acknowledgment of the fact that matter is neither created nor destroyed, but only changed as to its form, in any chemical reaction. of lavoisier's other work i can only mention the paper on "specific heats" contributed by laplace and lavoisier to the memoirs of the academy for . in this paper is described the ice calorimeter, whereby the amount of heat given out by a substance in cooling from one definite temperature to another is determined, by measuring the amount of ice converted into water by the heated substance in cooling through the stated interval of temperature. the specific heats of various substances, _e.g._ iron, glass, mercury, quicklime, etc., were determined by the help of this instrument. as we read the record of work done by lavoisier during the years between and --work which must have involved a great amount of concentrated thought as well as the expenditure of much time--we find it hard to realize that the most tremendous political and social revolution which the modern world has seen was raging around him during this time. in the earlier days of the french revolution, and in the time immediately preceding that movement, many minds had been stirred to see the importance of the study of nature; but it was impossible that natural science should continue to flourish when the tyrant robespierre had begun the reign of terror. the roll of those who perished during this time contains no more illustrious name than that of antoine laurent lavoisier. in the year lavoisier, who had for some time acted as a _fermier-général_ under the government, was accused of mixing with the tobacco "water and other ingredients hurtful to the health of the citizens." on this pretext he and some of his colleagues were condemned to death. for some days lavoisier found a hiding-place among his friends, but hearing that his colleagues had been arrested, he delivered himself up to the authorities, only asking that the death sentence should not be executed until he had completed the research in which he was engaged; "not" that he was "unwilling to part with life," but because he thought the results would be "for the good of humanity." "the republic has no need of chemists; the course of justice cannot be suspended," was the reply. on the th of may , the guillotine did its work; and in his fifty-first year lavoisier "joined the majority." to the honour of the academy of which he was so illustrious a member it is recorded that a deputation of his fellow-workers in science, braving the wrath of robespierre, penetrated to the dungeons of the prison and placed a wreath on the grave of their comrade. * * * * * the period of the infancy of chemical science which i have now briefly described is broadly contemporaneous with the second half of the eighteenth century. at this time the minds of men were greatly stirred. opinions and beliefs consecrated by the assent of generations of men were questioned or denied; the pretensions of civil and ecclesiastical authorities were withstood; assertions however strongly made, and by whatever authority supported, were met by demands for reasons. in france this revolt against mere authority was especially marked. led by the great thinker voltaire, the french philosophers attacked the generally accepted views in moral, theological and historical matters. a little later they began to turn with eager attention and hope to the facts of external nature. physical science was cultivated with wonderful vigour and with surprising success. in the sciences of heat and light we have at this time the all-important works of fourier, prévost and fresnel; in geology and natural history we have buffon and cuvier; the name of bichat marks the beginning of biological science, and chemistry takes rank as a science only from the time of lavoisier. from the philosophers an interest in natural science spread through the mass of the people. about the year the lecture-rooms of the great teachers of chemistry, astronomy, electricity, and even anatomy were crowded with ladies and gentlemen of fashion in the french capital. a similar state of matters was noticeable in this country. dr. black's lecture theatre was filled by an audience which comprised many young men of good position. to know something of chemistry became an essential part of the training of all who desired to be liberally educated. the secrets of nature were now rapidly explored; astonishing advances were made, and as a matter of course much opposition was raised. in this active, inquiring atmosphere the young science of chemistry grew towards maturity. priestley, ever seeking for new facts, announcing discovery after discovery, attacking popular belief in most matters, yet satisfied to interpret his scientific discoveries in terms of the hypothesis with which he was most familiar, was the pioneer of the advancing science. he may be compared to the advance-guard sent forward by the explorers of a new country with orders to clear a way for the main body: his work was not to level the rough parts of the way, or to fill in the miry places with well-laid metal, but rather rapidly to make a road as far into the heart of the country as possible. and we have seen how well he did the work. in his discovery of various kinds of airs, notably of oxygen, he laid the basis of the great generalizations of lavoisier, and, what was perhaps of even more importance, he introduced a new method into chemistry. he showed the existence of a new and unexplored region. before his time, hooke and mayow had proved the existence of more than one kind of air, but the chemistry of gases arose with the discoveries of priestley. although black's chief research, on fixed air and on latent heat, was completed fifteen or twenty years before priestley's discovery of oxygen, yet the kind of work done by black, and its influence on chemical science, mark him as coming after priestley in order of development. we have seen that the work of black was characterized by thoroughness and suggestiveness. the largeness of scope, the breadth of view, of this great philosopher are best illustrated in his discourses on heat; he there leads us with him in his survey of the domain of nature, and although he tells us that hypotheses are a "mere waste of time," we find that it is by the strength of his imagination that he commands assent. but he never allows the imagination to degenerate into fanciful guesses; he vigorously tests the fundamental facts of his theory, and then he uses the imagination in developing the necessary consequences of these facts. to black we owe not only the first rigorously accurate chemical investigation, but also the establishment of just ideas concerning the nature of heat. but lavoisier came before us as a greater than either priestley or black. to great accuracy and great breadth of view he added wonderful power of generalizing; with these, aided by marked mental activity and, on the whole, favourable external circumstances, he was able finally to overthrow the loose opinions regarding combustion and elementary principles which prevailed before his time, and so to establish chemistry as one of the natural sciences. at the close of the first period of advance we find that the sphere of chemistry has been defined; that the object of the science has been laid down, as being to find an explanation of the remarkable changes noticed in the properties of bodies; that as a first step towards the wished-for explanation, all material substances have been divided by the chemist into elements and compounds; that an element has been defined as any kind of matter from a given weight of which no simpler forms of matter--that is, no kinds of matter each weighing less than the original matter--have as yet been obtained; that the great principle of the indestructibility of matter has been established, viz. that however the properties of matter may be altered, yet the total mass (or quantity) remains unchanged; and lastly, we find that an explanation of one important class of chemical changes--those changes which occur when substances burn--has been found. and we have also learned that the method by which these results were obtained was this--to go to nature, to observe and experiment accurately, to consider carefully the results of these experiments, and so to form a general hypothesis; by the use of the mental powers, and notably by the use of the imagination, to develop the necessary deductions from this hypothesis; and finally, to try these deductions by again inquiring from nature "whether these things were so." before the time which we have been considering the paths of chemical science had scarcely yet been trodden. each discovery was full of promise, each advance displayed the possibility of further progress; the atmosphere was filled as with "a mighty rushing wind" ready to sweep away the old order of things. the age was an age of doubt and of freedom from the trammels of authority; it was a time eminently suited for making advances in natural knowledge. in the unceasing activity of priestley and lavoisier we may trace the influence of the restlessness of the age; but in the quietness and strength of the best work of these men, and notably in the work of black; in the calmness with which priestley bore his misfortunes at birmingham; in the noble words of lavoisier, "i am not unwilling to part with life, but i ask time to finish my experiments, because the results will, i believe, be for the good of humanity"--we see the truth of the assertion made by one who was himself a faithful student of nature-- "nature never did betray the heart that loved her." footnotes: [ ] the translation is taken from thomson's "history of chemistry." [ ] nevertheless, in other places lavoisier most readily acknowledges the merits of priestley. [ ] a similar method of reasoning was employed so far back as the tenth century: thus, in an anglo-saxon "manual of astronomy" we read, "there is no corporeal thing which has not in it the four elements, that is, air and fire, earth and water.... take a stick and rub it on something, it becomes hot directly with the fire which lurks in it; burn one end, then goeth the moisture out at the other end with the smoke." chapter iii. establishment of general principles of chemical science--period of dalton. _john dalton_, - . the progress of chemical knowledge became so rapid in the early years of the present century, that although i have in this chapter called the time immediately succeeding that of lavoisier "the period of john dalton," and although i shall attempt to describe the advances made by this philosopher without considering those of his contemporaries davy and berzelius, yet i must insist on the facts that this arrangement is made purely for the sake of convenience, and that many of the discoveries of davy, berzelius and others came in order of time before, or followed close upon the publication of dalton's atomic theory. nevertheless, as the work of these men belongs in its essence to the modern period, and as the promulgation of the atomic theory by dalton marks the beginning of this period, it seems better that we should have a clear conception of what was done by this chemist before proceeding to consider the advances made by his contemporaries and successors. * * * * * john dalton, the second of three children of joseph and deborah dalton, was born at eaglesfield, a village near cockermouth, in cumberland, on the th of september . one of the first meeting-houses established by the society of friends is to be found in eaglesfield. the dalton family had been settled for several generations on a small copyhold estate in this village. the first of them to join the friends was the grandfather of john dalton; his descendants remained faithful adherents of this society. dalton attended the village schools of eaglesfield and the neighbourhood until he was eleven years old, by which time, in addition to learning reading, writing and arithmetic, he had "gone through a course of mensuration, surveying, navigation, etc." at the age of ten his taste for measurements and calculations began to be remarked by those around him; this taste was encouraged by mr. robinson, a relative of dalton, who recognizing the indomitable perseverance of the boy appears to have taken some care about this time in directing his mathematical studies. at the early age of twelve dalton affixed to the door of his father's house a large sheet of paper whereon he announced that he had opened a school for youth of both sexes; also that "paper, pens and ink" were sold within. the boy-teacher had little authority over his pupils, who challenged their master to fight in the graveyard, and broke the windows of the room into which they had been locked till their tasks should be learned. when he was fifteen years old dalton removed to kendal, where he continued for eleven or twelve years, at first as assistant-master, and then, along with his elder brother jonathan, as principal of a boarding school for boys. it was announced by the brothers that in this school "youth will be carefully instructed in english, latin, greek and french; also writing, arithmetic, merchants' accounts and the mathematics." the school was not very successful. both brothers were hard, inflexible, and ungainly in their habits, and neither was fitted to become a successful teacher of boys: of the two, john had the gentler disposition, and was preferred by the boys; "besides, his mind was so occupied by mathematics that their faults escaped his notice." during this time dalton employed his leisure in learning latin, greek and french, and in pursuing his studies in mathematics and natural philosophy. he became a frequent contributor to the _gentlemen's diary_, a paper which received problems of various kinds--chiefly mathematical--and presented prizes for their successful solution. besides setting and answering mathematical problems in this journal, and also in the _ladies' diary_, dalton sometimes ventured into the wider fields of mental phenomena. it seems strange to read that, even at the age of twenty-six, dalton should occupy his leisure time composing answers to such queries as these:-- "whether, to a generous mind, is the conferring or receiving an obligation, the greater pleasure?" "is it possible for a person of sensibility and virtue, who has once felt the passion of love in the fullest extent that the human heart is capable of receiving it (being by death or some other circumstance for ever deprived of the object of its wishes), ever to feel an equal passion for any other object?" in his answer to the second of these queries, dalton carefully framed two hypotheses, and as carefully drew conclusions from each. the question in the _diary_ was by "mira;" if "mira" were a "rapturous maiden" she would not derive much comfort from the cold and mathematical answer by "mr. john dalton of kendal." at kendal dalton made the acquaintance of mr. gough, who was about eight years older than dalton, and had been blind from the age of two. mr. gough, we are assured by dalton, was "a perfect master of the latin, greek and french tongues;" he understood "well all the different branches of mathematics;" there was "no branch of natural philosophy but what he was well acquainted with;" he knew "by the touch, taste and smell, almost every plant within twenty miles of kendal." to the friendship of this remarkable man dalton owed much; with his help he acquired a fair knowledge of the classical languages, and he it was who set dalton the example of keeping a regular record of weather observations. on the th of march dalton made his first entry in a book which he entitled "observations on the weather, etc.;" the last entry in this book he made fifty-seven years later on the evening preceding his death. the importance of dalton's meteorological observations, as leading him to the conception of the atomic theory, will be noticed as we proceed. in the year dalton, who was now twenty-seven years of age, was invited to manchester to become tutor in the mathematical and natural philosophy department of a college recently established by influential dissenters in that town. eighty pounds for the session of ten months was guaranteed him; and he was provided with "rooms and commons" in the college at a charge of £ _s._ per session. he held this appointment for six years, when he retired, and continuing to live in manchester devoted himself to researches in natural philosophy, gaining a living by giving private lessons in mathematics and physical science at a charge of _s._ _d._ per hour, or _s._ _d._ each if more than two pupils attended at the same time. dalton was elected a fellow of the literary and philosophical society of manchester in the year ; and from the time of his retiring from the tutorship of manchester new college till the close of his life he spent a great part of his time in a room in the society's house in george street, in studying and teaching. the fifty years thus spent are marked by few outward events. the history of dalton's life from this time is the history of the development of his intellect, and the record of his scientific discoveries. on one occasion during dalton's stay at kendal, as he was about to make a visit to his native village, he bethought himself that the present of a pair of silken hose would be acceptable to his mother. he accordingly purchased a pair marked "newest fashion;" but his mother's remark, "thou hast brought me a pair of grand hose, john; but what made thee fancy so light a colour? i can never show myself at meeting in them," rather disconcerted him, as to his eyes the hose were of the orthodox drab colour. his mother insisted that the stockings were "as red as a cherry." john's brother upheld the "drab" side of the dispute; so the neighbours were called in, and gave their decision that the hose were "varra fine stuff, but uncommon scarlety." from this time dalton made observations on the peculiarities of his own vision and that of others, and in his first paper read before the literary and philosophical society in , he described these peculiarities. he says, "since the year the occasional study of botany obliged me to attend more to colour than before. with respect to colours that were white, yellow, or green, i readily assented to the appropriate term; blue, purple, pink and crimson appeared rather less distinguishable, being, according to my idea, all referable to blue. i have often seriously asked a person whether a flower was blue or pink, but was generally considered to be in jest." dalton's colour-blindness was amusingly illustrated at a later time, when having been created d.c.l. by the university of oxford he continued to wear the red robes of his degree for some days; and when his attention was drawn to the somewhat strange phenomenon, even in a university town, of an elderly gentleman in the dress of a quaker perambulating the town day after day in a scarlet robe, he remarked that to him the gown appeared to be of the same colour as the green trees. dalton's work during the next six or eight years dealt chiefly with problems suggested by his meteorological observations; he published a volume on "meteorological observations and essays," chiefly occupied with descriptions of the instruments employed, more especially of the thermometer and barometer, and an instrument for determining the dew-point of air. by this time he had established the existence of a connection of some kind between magnetism and the aurora, and had thus laid the foundations of a most important branch of meteorology. in , in a note to a paper on rain and dew, he begins his work on aqueous vapour in the atmosphere by proving that water vapour exists as such in the air. this paper is quickly followed by another on the conducting power of water for heat. a very important paper was published in , on the "constitution of mixed gases, etc.," wherein dalton asserted that the total pressure of a mixture of two gases on the walls of the containing vessel is equal to the sum of the pressures of each gas; in other words, that if one gas is removed the pressure now exerted by the remaining gas is exactly the same as was exerted by that gas in the original mixture. in a paper published much later ( ), when his views and experiments on this subject were matured, he writes: "it appears to me as completely demonstrated as any physical principle, that whenever two or more ... gases or vapours ... are put together, either into a limited or unlimited space, they will finally be arranged each as if it occupied the whole space, and the others were not present; the nature of the fluids and gravitation being the only efficacious agents." this conclusion was followed out and extended in a paper published in , on the absorption of gases by water and other liquids, wherein he states that the amount of each gas _mechanically dissolved_ by a liquid from a mixture of gases depends only on the quantity of _that_ gas in the mixture, the other gases exerting no influence in this respect. dalton now considered the variation in the pressures of various gases caused by increasing or decreasing temperature, and then proceeded to discuss the relations which exist between the volumes of gases and the temperature at which these volumes are measured. he concluded that "all elastic fluids" under the same pressure expand equally by heat: and he adds the very important remark, "it seems, therefore, that general laws respecting the absolute quantity and the nature of heat are more likely to be derived from the study of elastic fluids than of other substances"--a remark the profound truth of which has been emphasized by each step in the advances made in our conception of the nature of heat since the time of dalton. in these papers on the "constitution of mixed gases" dalton also describes and illustrates a method whereby the actual amount of water vapour in a given bulk of atmospheric air may be found from a knowledge of the dew-point of that air, that is, the temperature at which the deposition of water in the liquid form begins. the introduction of this method for finding the humidity of air marks an important advance in the history of meteorology. in this series of papers published within the first three years of the present century dalton evidently had before his mind's eye a picture of a gas as a quantity of matter built up of small but independent particles; he constantly speaks of pressures between the small particles of elastic fluids, of these particles as repelling each other, etc. in his "new system" he says, "a vessel full of any pure elastic fluid presents to the imagination a picture like one full of small shot." it is very important to notice that dalton makes use of this conception of small particles to explain purely physical experiments and operations. although we know that during these years he was thinking much of "chemical combinations," yet we find that it was his observations on the weather which led him to the conception--a purely physical conception--of each chemically distinct gas as being built up of a vast number of small, equally heavy particles. a consideration of these papers by dalton on the constitution of mixed gases shows us the method which he pursued in his investigations. "the progress of philosophical knowledge," he says, "is advanced by the discovery of new and important facts; but much more when these facts lead to the establishment of general laws." dalton always strove to attain to general laws. the facts which he describes are frequently inaccurate; he was singularly deficient in manipulation, and he cannot claim a high place as a careful experimenter. he was however able to draw general conclusions of wide applicability. he seems sometimes to have stated a generalization in definite form before he had obtained any experimental verification of it. in the year dalton conducted an examination of air from various localities, and concluded that one hundred volumes of air are composed of twenty-one volumes of oxygen and seventy-nine volumes of nitrogen. this appears to have been his first piece of purely chemical work. but in the next year he again returns to physical phenomena. in the paper already referred to, on the absorption of gases by water and other liquids, published in this year, he had stated that "all gases that enter into water and other liquids by means of pressure, and are wholly disengaged again by the removal of that pressure, are _mechanically_ mixed with the liquid, and not _chemically_ combined with it." but if this be so, why, he asked, does not water mechanically dissolve the same bulk of every kind of gas? the answer which he gives to this question is found at the close of the paper; to the student of chemistry it is very important:-- "this question i have duly considered, and though i am not yet able to satisfy myself completely, i am nearly persuaded that the circumstance depends upon the weight and number of the ultimate particles of the several gases, those whose particles are lightest and single being least absorbable, and the others more, accordingly as they increase in weight and complexity. an inquiry into the relative weights of the ultimate particles of bodies is a subject, as far as i know, entirely new. i have lately been prosecuting this inquiry with remarkable success. the principle cannot be entered upon in this paper; but i shall just subjoin the results, as far as they appear to be ascertained by my experiments." then follows a "_table of the relative weights of the ultimate particles of gaseous and other bodies._" the following numbers, among others, are given:-- hydrogen sulphur · oxygen · alcohol · azote · nitrous oxide · phosphorus · ether · here is the beginning of the atomic theory; and yet dalton's strictly chemical experimental work lies in the future. the scope of the theory is defined in that sentence--"_an inquiry into the relative weights of the ultimate particles of bodies._" his paper on mixed gases is illustrated by a plate,[ ] which shows how vividly dalton at this time pictured to himself a quantity of gas as composed of many little particles, and how clearly he recognized the necessity of regarding all the particles of each elementary gas as alike, but as differing from those of every other elementary gas. in dalton was invited to deliver a course of lectures in the royal institution of london, on heat, mixed gases and similar subjects. in these lectures he expounded his views on the constitution of gases, on absorption of gases by liquids, etc. these views drew much attention in this and other countries. "they are busy with them," he writes in , "at london, edinburgh, paris and in various parts of germany, some maintaining one side and some another. the truth will surely out at last." [illustration: fig. ] dalton's love of numerical calculations is noticeable in a trivial circumstance which he mentions in a letter from london to his brother. he tried to count the number of coaches which he met in going to the friends' morning meeting: this he assures his brother he "effected with tolerable precision. the number was one hundred and four." during vacation time dalton usually made a walking excursion in the lake district. he was extremely fond of mountain scenery, but generally combined the pursuit of science with that of pleasure; he carried his meteorological instruments with him, determined the dew-point at various altitudes, and measured mountain heights by the aid of his barometer. sometimes however he refused to have anything to do with science. a companion in one of these excursions says that he was "like a schoolboy enjoying a holiday, mocking the cuckoos, putting up and chasing the hares, stopping from time to time to point out some beautiful view, or loitering to chat with passing pedestrians." this side of dalton's nature was not often apparent. in him the quiet, hard-working student generally appeared prominently marked; but on the half-holiday which he allowed himself on each thursday afternoon, in order to enjoy the society of a few friends and to engage in his favourite amusement of a game at bowls, he laid aside something of the quietness, regularity and decorum which usually characterized him. "when it came to his turn to bowl he threw his whole soul into the game,... and it was not a little amusing to spectators to see him running after the ball across the green, stooping down as if talking to it, and waving his hands from one side to the other exactly as he wished the line of the ball to be, and manifesting the most intense interest in its coming near to the point at which he aimed." from the year - dalton becomes more and more a worker in chemistry. the establishment of the atomic theory now engaged most of his time and attention. the results of his investigation of "the primary laws which seem to obtain in regard to heat and to chemical combinations" appeared in his "new system of chemical philosophy," part i. of which, "on heat, on the constitution of bodies and on chemical synthesis," was published in . we have now arrived at the time when dalton's inquiry into the "relative weights of the ultimate particles of bodies" was in his opinion sufficiently advanced for presentation to the scientific world; but i think we shall do better to postpone our consideration of this great inquiry until we have completed our review of the chief events in the life of dalton, other than this the greatest event of all. dalton did not look for rewards--he desired only the just fame of one who sought for natural truths; but after the publication of the "new system" rewards began to come to him. in he was elected a corresponding member of the french academy of sciences. in , when his fame as a philosophical chemist was fully established, dalton visited paris. this visit gave him great pleasure. he was constantly in the society of the great men who then so nobly represented the dignity of natural science in france; laplace, cuvier, biot, arago, gay-lussac, milne-edwards and others were his friends. for some time after this visit he was more vivacious and communicative than usual, and we are told by one who lived in the same house as he, "we frequently bantered him with having become half a frenchman." dalton especially valued the friendship of clementine cuvier, daughter of the great naturalist, with whom he became acquainted during his visit to paris. all through life he greatly delighted in the society of cultivated women, and his warmest friendships were with gentlewomen. at one time, shortly after going to manchester, he was much taken by a widow lady who combined great personal charms with considerable mental culture. "during my _captivity_," he writes to a friend, "which lasted about a week, i lost my appetite, and had other symptoms of _bondage_ about me, as incoherent discourse, etc., but have now happily regained my freedom." the society of men who like himself were actively engaged in the investigation of natural science was also a source of much pleasure to dalton. such men used to visit him in manchester, so that in the house of the rev. mr. johns, in whose family he lived, "there were found from time to time some of the greatest philosophers in europe." dalton was elected a fellow of the royal society in , and four years later he became the first recipient of one of the royal medals, then founded by the king (george iv.). in he was elected one of the eight foreign associates of the french academy, an honour which is generally regarded as the highest that can be bestowed on any man of science. dalton was one of the original members of the british association for the advancement of science, and he attended most of the meetings from the first held in york in to that held in manchester two years before his death. at the oxford meeting of he was created d.c.l. by the university, and two years later the university of edinburgh honoured herself by enrolling his name on the list of her doctors of law. about this time some of dalton's scientific friends, who considered his work of great national importance, endeavoured to obtain a pension for him from the civil list. at the meeting of the british association held at cambridge in , the president, professor sedgwick, was able to announce that "his majesty, willing to manifest his attachment to science, and his regard for a character like that of dr. dalton, had graciously conferred on him, out of the funds of the civil list, a substantial mark of his royal favour." the "substantial mark of royal favour," the announcement of which dalton received "with his customary quietness and simplicity of manner," consisted of a pension of £ _per annum_, which was increased three years later to £ . the second part of volume i. of his "new system" was published by dalton in , and the second volume of the same work in . in a paper by him was read before the british association, in which he announced some important discoveries with regard to the water in crystallizable salts, and thus brought a new class of facts within the range of the atomic theory. he was seized with paralysis in , but recovered to a great extent; a second attack in however completely prostrated him. on the th of july in that year he made the last entry in his book of "observations on the weather"--"_little rain_;" next morning he became insensible and quietly passed away. * * * * * it is as the founder of the chemical atomic theory that dalton must ever be remembered by all students of physical and chemical science. to the greek philosophers leucippus and democritus (flourished about - b.c.) we owe the conception that "the bodies which we see and handle, which we can set in motion or leave at rest, which we can break in pieces and destroy, are composed of smaller bodies, which we cannot see or handle, which are always in motion, and which can neither be stopped, nor broken in pieces, nor in any way destroyed or deprived of the least of their properties" (clerk maxwell). the heavier among these small indivisible bodies or atoms were regarded as always moving downwards. by collisions between these and the lighter ascending atoms lateral movements arose. by virtue of the natural law (as they said) that things of like weight and shape must come to the same place, the atoms of the various elements came together; thus larger masses of matter were formed; these again coalesced, and so finally worlds came into existence. this doctrine was extended by epicurus ( - b.c.), whose teaching is preserved for us in the poem of lucretius ( - b.c.), "de rerum natura;" he ascribed to the atoms the power of deviating from a straight line in their descending motion. on this hypothesis epicurus built a general theory to explain all material and spiritual phenomena. the ceaseless change and decay in everything around them was doubtless one of the causes which led men to this conception of atoms as indivisible, indestructible substances which could never wear out and could never be changed. but even here rest could not be found; the mind was obliged to regard these atoms as always in motion. the dance of the dust-motes in the sunbeam was to lucretius the result of the more complex motion whereby the atoms which compose that dust are agitated. in his dream as told by tennyson-- "a void was made in nature: all her bonds cracked: and i saw the flaring atom-streams and torrents of her myriad universe, ruining along the illimitable inane, fly on to clash together again, and make another and another frame of things for ever." the central quest of the physicist, from the days of democritus to the present time, has been to explain the conception of "atom"--to develop more clearly the observed properties of the things which are seen and which may be handled as dependent on the properties of those things which cannot be seen, but which yet exist. for two thousand years he has been trying to penetrate beneath the ever-changing appearances of nature, and to find some surer resting-place whence he may survey these shifting pictures as they pass before his mental vision. the older atomists thought to find this resting-place, not in the atoms themselves, but in the wide spaces which they supposed to exist between the worlds:-- "the lucid interspace of world and world where never creeps a cloud, or moves a wind, nor ever falls the least white star of snow, nor ever lowest roll of thunder moans, nor sound of human sorrow mounts to mar their sacred everlasting calm." to the modern student of science the idea of absolute rest appears unthinkable; but in the most recent outcome of the atomic theory--in the vortex atoms of helmholtz and thomson--he thinks he perceives the very "foundation stones of the material universe." newton conceived the atom as a "solid, massy, hard, impenetrable, movable particle." to the mind of d. bernoulli the pressure exerted by a gas on the walls of a vessel enclosing it was due to the constant bombardment of the walls by the atoms of which the gas consisted. atomic motion was the leading idea in the explanation of heat given by rumford and davy, and now universally accepted; and, as we have seen, dalton was himself accustomed to regard all "elastic fluids" (_i.e._ gases) as consisting of vast numbers of atoms. but in the year or so, dalton thought that by the study of chemical combinations it would be possible to determine the relative weights of atoms. assume that any elementary gas is composed of small, indivisible, equally heavy parts; assume that the weight of an atom of one element is different from that of the atom of any other element; and, lastly, assume that when elements combine the atom of the compound so produced is built up of the atoms of the various elements. make these assumptions, and it follows that the relative weights of two or more elements which combine together must represent the relative weights of the atoms of these elements. we know that the fixity of composition of chemical compounds had been established before this time, largely by the labours of black and lavoisier. fixity of composition had however been called in question by berthollet, who held that elements combine together in very varying quantities; that, in fact, in place of there being two or three, or a few definite compounds of, say, iron and oxygen, there exists a graduated series of such bodies; and that the amount of iron which combines with oxygen depends chiefly on such physical conditions as the temperature, the pressure, etc., under which the chemical action occurs. but by the date of the publication of the first part of dalton's "new system," the long dispute between berthollet and proust regarding fixity of composition of compounds had nearly closed in favour of the latter chemist, who strongly upheld the affirmative side of the argument. but if dalton's assumptions are correct, it is evident that when two elements form more than one compound, the quantity of element a in one of these must be a simple multiple of the quantity in the other of these compounds; because there must be a greater number of atoms of element a in the atom of one compound than in that of the other compound, and an elementary atom is assumed to be indivisible. hence it follows that if one element be taken as a standard, it must be possible to affix to any other element a certain number which shall express the smallest quantity of that element which combines with one part by weight of the standard element; and this number shall also represent how many times the atom of the given element is heavier than the atom of the standard element, the weight of which has been taken to be _one_. if this element forms two compounds with the standard element, the amount of this element in the second compound must be expressed by a simple multiple of the number assigned to this element, because it is not possible, according to the fundamental assumptions of the theory, to form a compound by the combination of fractions of elementary atoms. by pondering on the facts regarding chemical combinations which had been established by various workers previous to the year , dalton had apparently come to such conclusions as those now indicated. in his paper on the properties of the gases constituting the atmosphere, read to the manchester society on november , , he stated that one hundred measures of common air would combine with thirty-six measures of "nitrous gas" in a narrow tube to produce an oxide of nitrogen, but with seventy-two measures of the same gas in a wide vessel to produce another oxide of nitrogen. these facts, he says, "clearly point out the theory of the process: the elements of oxygen may combine with a certain portion of nitrous gas, or with twice that portion, but with no intermediate quantity." in the concluding paragraph of his paper on absorption of gases by liquids, read on october , , we found (see p. ) that he had got so far in his inquiry into the "relative weights of the ultimate particles of bodies" as to give a table of twenty-one such weights. about this time dalton made analyses of two gaseous compounds of carbon--olefiant gas and carburetted hydrogen or marsh-gas. he found that both are compounds of carbon and hydrogen; that in one . parts by weight of carbon are combined with one part by weight of hydrogen, and in the other the same amount ( . ) of carbon is combined with two parts by weight of hydrogen.[ ] this was a striking confirmation of his views regarding combination in multiple proportions, which views followed as a necessary deduction from the atomic hypothesis. from this time he continued to develop and extend this hypothesis, and in the year he published his "new system of chemical philosophy." the first detailed account of the atomic theory was however given to the chemical world the year before dalton's book appeared. during a conversation with dalton in the autumn of dr. thomas thomson learned the fundamental points of the new theory, and in the third edition of his "system of chemistry," published in , he gave an account of dalton's views regarding the composition of bodies. in the same year a paper by thomson appeared in the _philosophical transactions_, wherein it was experimentally proved that oxalic acid combines with strontia to form two distinct compounds, one of which contains twice as much oxalic acid as the other, the amount of strontia being the same in both. analyses of the oxalates of potash, published about the same time by wollaston, afforded another illustration of the _law of multiple proportions_, and drew the attention of chemists to dalton's theory. but the new theory was opposed by several very eminent chemists, notably by sir humphry davy. in the autumn of wollaston, thomson and davy were present at the dinner of the royal society club, at the crown and anchor, in the strand. after dinner, these three chemists discussed the new theory for an hour and a half, wollaston and thomson trying to convince davy of the truth of dalton's theory; but "so far from being convinced, he went away, if possible, more prejudiced against it than ever." soon after this wollaston succeeded in convincing mr. davis gilbert (afterwards president of the royal society) of the justness of the atomic theory, and he in turn so placed the facts and the reasoning before davy, that from this time he became a supporter of the new theory. in order that the atomic theory should be fruitful of results, it was now necessary that the values of the atomic weights of many elements should be carefully determined. let us consider what knowledge must be acquired before the value to be assigned to the atomic weight of an element can be found. hydrogen was the element chosen as a standard by dalton. he assumed that the atom of hydrogen weighs ; the atomic weight of any other element is therefore a number which tells how many times the atom of that element is heavier than the atom of hydrogen. thus, when dalton said the atomic weight of oxygen is , he meant that the atom of oxygen is eight times heavier than that of hydrogen. how was this number obtained? accurate analyses of water show that in this liquid one part by weight of hydrogen is combined with eight parts by weight of oxygen; but (it is said) as the atom of hydrogen weighs , the atom of oxygen must weigh . in drawing this conclusion it is assumed that the atom, or smallest particle, of water is built up of one atom of hydrogen and one atom of oxygen. let it be assumed that the atom of water contains two atoms of hydrogen and one of oxygen, then the latter atom must weigh sixteen times as much as each atom of hydrogen; let it be assumed that three atoms of hydrogen combine with one atom of oxygen to form an atom of water, then the weight of the oxygen atom must be twenty-four times that of the hydrogen atom. any one of these assumptions will equally satisfy the figures obtained by analyzing water ( : = : = : ). now, had we any method whereby we could determine how many times an atom of water is heavier than an atom of hydrogen we should be able to determine which of the foregoing assumptions is correct, and therefore to determine the atomic weight of oxygen. hence, before the atomic weight of an element can be determined, there must be found some method for determining the atomic weights of compounds of that element. unless this can be done the atomic theory is of little avail in chemistry. i conceive it to be one of the signal merits of dalton that he so clearly lays down rules, the best which could be devised at his time, for determining the atomic weights of compounds, or, what is the same thing, for determining the number of elementary atoms in one atom of any compound. in his "new system" he says that he wishes to show the importance of ascertaining "the relative weights of the ultimate particles both of simple and compound bodies, the number of simple elementary particles which constitute one compound particle, and the number of less compound particles which enter into the formation of one more compound particle." considering compounds of two elements, he divides these into binary, ternary, quaternary, etc., according as the compound atom contains two, three, four, etc., atoms of the elements. he then proceeds thus-- "the following general rules may be adopted as guides in all our investigations respecting chemical synthesis:-- " st. when only one combination of two bodies can be obtained, it must be presumed to be a _binary_ one, unless some cause appear to the contrary. " nd. when two combinations are observed, they must be presumed to be a _binary_ and a _ternary_. " rd. when three combinations are obtained, we may expect one to be _binary_ and the other two _ternary_. " th. when four combinations are observed, we should expect one _binary_, two _ternary_, and one _quaternary_," etc. only one compound of hydrogen and oxygen was then known; hence it was presumed to be a binary compound, _i.e._ a compound the smallest particle of which consisted of one atom of hydrogen and one atom of oxygen; and hence, from the data already given on page , it followed that the atomic weight of oxygen was . two compounds of carbon and oxygen were known, each containing six parts by weight of carbon, in one case united with eight, and in the other case with sixteen parts by weight of oxygen. from dalton's rules one of these was a binary, and the other a ternary compound; but as the atomic weight of oxygen had already been determined to be , that compound of carbon and oxygen containing eight of oxygen combined with six of carbon was decided to be binary, and that containing sixteen of oxygen (_i.e._ two atoms) to be ternary; and hence the atomic weight of carbon was determined to be . in the second part of the "new system" dalton, guided by these rules, determined experimentally the atomic weights of a great many substances; but this was not the kind of work suited to dalton's genius. his analytical determinations were generally inaccurate; nevertheless, he clearly showed how the values of the atomic weights of elements ought to be established, and he obtained results sufficiently accurate to confirm his general theory. to make accurate determinations of the relative weights of elementary atoms was one of the tasks reserved for the great swedish chemist berzelius (see pp. - ). when we examine dalton's rules we must confess that they appear somewhat arbitrary. he does not give reasons for his assertion that "when only one combination of two bodies can be obtained, it must be presumed to be a binary one." why may it not be ternary or quaternary? why must the atom of water be built up of one atom of hydrogen combined with one atom of oxygen? or, when two compounds are known containing the same pair of elements, why must one be binary and the other ternary? or, even assuming that this _must_ be justified by facts, does it follow that dalton's interpretation of the atomic structure of the two oxides of carbon is necessarily correct? these oxides contain of carbon + of oxygen, and of carbon + of oxygen, respectively. take the second, : = : ; assume this to be a binary compound of one atom of oxygen (weighing ) with one atom of carbon (weighing ), then the other will be a ternary compound containing one atom of oxygen ( ) and two atoms of carbon ( ). hence it appears that dalton's rules were too arbitrary, and that they were insufficient to determine with certainty the atomic weights of some of the elements. nevertheless, without some such rules as those of dalton, no great advances could have been made in applying the atomic theory to the facts of chemical combination; and dalton's rules were undoubtedly founded on wide considerations. in the appendix to volume ii. of his "new system" he expressly states that before the number of atoms of two elements present in the atom of a compound can be determined, it is necessary that many combinations should be examined, not only of these elements with each other, but also of each of these with other elements; and he tells us that to gather together facts bearing on this general question of chemical synthesis was the object of his work from the time of the promulgation of the atomic theory. when we find that dalton applied the term "atom" to the small particles of compound bodies, we at once see that by atom he could not always mean "that which cannot be cut;" he simply meant the smallest particle of a substance which exhibits the properties of that substance. a mass of water vapour was conceived by dalton as "like a mass of small shot." each shot exhibited the characteristic chemical properties of water vapour; it differed from the large quantity of vapour only in mass; but if one of these little pieces of shot were divided--as dalton, of course, knew it could be divided--smaller pieces of matter would be produced. but these would no longer be water; they would be new kinds of matter. they are called oxygen and hydrogen. as aids towards gaining a clear conception of the "atom" of a compound as a definite building, dalton made diagrammatic representations of the hypothetical structures of some of these atoms: the following plate is copied from the "new system:"--a represents an atom of alum; b, an atom of nitrate of alumina; c, of barium chloride; d, of barium nitrate; e, of calcium chloride; f calcium nitrate; g, of calcium sulphate; h, potassium carbonate; i, of potash; and k, an atom of soda. [illustration: fig. .] but i think if we consider this application of the term "atom" to elements and compounds alike, we shall see objections to it. when an atom of a compound is divided the smaller particles so produced are each very different in chemical properties from the atom which has just been divided. we may, if we choose, assume that the atom of an element could in like manner be divided, and that the products of this division would be different from the elementary atoms; but such a division of an elementary atom has not as a matter of fact been yet accomplished, unless we class among elements substances such as potash and soda, which for many years were universally regarded as elements, and rightly so regarded because they had not been decomposed. in dalton's nomenclature then, the term "atom" is applied alike to a small particle with definite properties known to be divisible into smaller particles, each with properties different from those of the undivided particle, and to a small particle which, so far as our knowledge goes, cannot be divided into any particle smaller than or different from itself. nevertheless, if the atomic theory was to be victorious, it was necessary that it should be applied to elements and compounds alike. until a clear conception should be obtained, and expressed in accurate language, of the differences in structure of the ultimate particles of compounds and of elements, it was perhaps better to apply the term "atom" to both alike. these two difficulties--( ) the difficulty of attaching to the term "atom" a precise meaning applicable to elements and compounds alike, and ( ) the difficulty of determining the number of elementary atoms in the atom of a given compound, and hence of determining the relative weights of elementary atoms themselves--were for many years stumbling-blocks in the path of the upholders of the daltonian theory. the very great difficulty of clearly comprehending the full meaning of dalton's proposed theory becomes apparent when we learn that within three years from the publication of part i. of the "new system," facts were made known by the french chemist gay-lussac, and the true interpretation of these facts was announced by the italian chemist avogadro, which facts and interpretation were sufficient to clear away both the difficulties i have just mentioned; but that nevertheless it is only within the last ten or fifteen years that the true meaning of the facts established by gay-lussac and the interpretation given by avogadro have been generally recognized. in gay-lussac, in a memoir on the combination of gaseous bodies, proved that gases combine chemically in simple proportions by volume, and that the volume of the product always bears a simple relation to the volumes of the combining gases. thus, he showed that two volumes of hydrogen combine with one volume of oxygen to form two volumes of water vapour; that one volume of nitrogen combines with three volumes of hydrogen to form two volumes of ammonia gas, and so on. now, as elements combine atom with atom, the weights of these combining volumes of elements must represent the relative weights of the atoms of the same elements. in avogadro distinguished between the ultimate particles of compounds and elements. let a gaseous element, a, combine with another gaseous element, b, to form a gaseous compound, c; then avogadro supposed that the little particles of a and the little particles of b (dalton's atoms) split up, each into two or more smaller particles, and that these smaller particles then combine together to form particles of the compound c. the smaller particles produced by splitting a daltonian elementary atom were regarded by avogadro as all identical in properties, but these very small particles could not exist uncombined either with each other or with very small particles of some other element. when the atom of a compound is decomposed, avogadro pictured this atom as splitting into smaller particles of two or three or more different kinds, according as the compound had contained two or three or different elements. to avogadro's mental vision an elementary gas appeared as built up of a great many little particles, each exhibiting in miniature all the properties of the gas. the gas might be heated, or cooled, or otherwise physically altered, but each of the little particles remained intact; the moment however that this gas was mixed with another on which it could chemically react, these little particles split into smaller parts, but as the smaller parts so produced could not exist in this state, they seized hold of the corresponding very small parts of the other gas, and thus a particle of a compound gas was produced. a compound gas was pictured by avogadro as also built up of small particles, each exhibiting in miniature the properties of the gas, and each remaining undecomposed when the gas was subjected only to physical actions; but when the gas was chemically decomposed, each little particle split, but the very small parts thus produced, being each a particle of an elementary substance, continued to exist, and could be recognized by the known properties of that element. to the smallest particle of any substance (elementary or compound) which exhibits the properties of that substance, and which cannot be split into parts without destroying these properties, we now give the name of _molecule_. a molecule is itself a structure. it is built up of parts; each of these parts we now call an _atom_. the molecule of a compound is, of course, composed of the atoms of the elements which form that compound. the molecule may contain two or three or more unlike atoms. the molecule of an element is composed of the atoms of that element, and all of these atoms are supposed to be alike. we cannot get hold of elementary atoms and examine them, but we have a large mass of evidence in favour of the view which regards the molecule of an element as composed of parts each weighing less than the molecule itself. the student of physics or chemistry now believes that, were a very small quantity of a gas (say ammonia) or a drop of a liquid (say water) magnified to something like the size of the earth, he should see before him a vast heap of particles of ammonia or of water, each exhibiting all the properties by the possession of which he now distinguishes ammonia or water from all other kinds of matter. he believes that he should see these particles in motion, each moving rapidly from place to place, sometimes knocking against another, sometimes traversing a considerable space without coming into collision with any other. but the student tries to penetrate yet further into the nature of things. to the vision of the chemist these particles of almost inconceivable minuteness are themselves built up of smaller particles. as there is an architecture of masses, so is there an architecture of molecules. hydrogen and oxygen are mixed; the chemist sees the molecules of each in their never-ceasing dance moving here and there among the molecules of the other, yet each molecule retaining its identity; an electric spark is passed through the mixture, and almost instantaneously he sees each hydrogen molecule split into two parts, and each oxygen molecule split into two parts, and then he sees these parts of molecules, these atoms, combine, a pair of hydrogen atoms with an atom of oxygen, to form compound molecules of water. avogadro's hypothesis gave the chemist a definition of "molecule;" it also gave him a definition of "atom." it is evident that, however many atoms of a given element there may be in this or in that compound molecule, no compound of this element can exist containing less than a single atom of the element in question; therefore an atom of an element is the smallest quantity of that element in the molecule of any compound thereof. and so we have come back to the original hypothesis of dalton; but we have extended and modified that hypothesis--we have distinguished two orders of small particles, the molecule (of a compound or of an element) and the atom (of an element). the combination of two or more elements is now regarded as being preceded by the decomposition of the molecules of these elements into atoms. we have defined molecule and we have defined atom, but before we can determine the relative weights of elementary atoms we must have a means of determining the relative weights of compound molecules. the old difficulty still stares us in the face--how can we find the number of elementary atoms in the molecule of a given compound? the same naturalist who enriched chemical science by the discovery of the molecule as distinct from the atom, placed in the hands of chemists the instrument for determining the relative weights of molecules, and thus also the relative weights of atoms. the great generalization, usually known as _avogadro's law_, runs thus: "_equal volumes of gases measured at the same temperature and under the same pressure contain equal numbers of molecules._" gay-lussac had concluded that "equal volumes of gases contain equal numbers of atoms;" but this conclusion was rejected, and rightly rejected by dalton, who however at the same time refused to admit that there is a simple relation between the combining volumes of elements. the generalization of avogadro has however stood the test of experiment, and is now accepted as one of the fundamental "laws" of chemical science. like the atomic theory itself, avogadro's law is an outcome of physical work and of physical reasoning. of late years the great naturalists, clausius, helmholtz, joule, rankine, clerk maxwell and thomson have developed the physical theory of molecules, and have shown that avogadro's law may be deduced as a necessary consequence from a few simple physical assumptions. this law has thus been raised, from being a purely empirical generalization, to the rank of a deduction from a wide, yet simple physical theory. now, if "equal volumes of gases contain equal numbers of molecules," it follows that the ratio of the densities of any two gases must also be the ratio of the weights of the molecules which constitute these gases. thus, a given volume of water vapour weighs nine times more than an equal volume of hydrogen; therefore the molecule of gaseous water is nine times heavier than the molecule of hydrogen. one has therefore only to adopt a standard of reference for molecular weights, and avogadro's law gives the means of determining the number of times any gaseous molecule is heavier than that of the standard molecule. but consider the combination of a gaseous element with hydrogen; let us take the case of hydrogen and chlorine, which unite to form gaseous hydrochloric acid, and let us determine the volumes of the uniting elements and the volume of the product. here is a statement of the results: one volume of hydrogen combines with one volume of chlorine to form two volumes of hydrochloric acid. assume any number of molecules we please in the one volume of hydrogen--say ten--there must be, by avogadro's law, also ten molecules in the one volume of chlorine; but inasmuch as the volume of hydrochloric acid produced is double that of either the hydrogen or the chlorine which combined to form it, it follows, by the same law, that twenty molecules of hydrochloric acid have been formed by the union of ten molecules of hydrogen with ten molecules of chlorine. the necessary conclusion is that each hydrogen molecule and each chlorine molecule has split into two parts, and that each half-molecule (or atom) of hydrogen has combined with one half-molecule (or atom) of chlorine, to produce one compound molecule of hydrochloric acid. therefore we conclude that the hydrogen molecule is composed of two atoms, and that the chlorine molecule is also composed of two atoms; and as hydrogen is to be our standard element, we say that if the atom of hydrogen weighs one, the molecule of the same element weighs two. it is now easy to find the _molecular weight_ of any gas; it is only necessary to find how many times heavier the given gas is than hydrogen, the weight of the latter being taken as . thus, oxygen is sixteen times heavier than hydrogen, but : = : , therefore the molecule of oxygen is thirty-two times heavier than the molecule of hydrogen. ammonia is eight and a half times heavier than hydrogen, but : - / = : , therefore the molecule of ammonia is seventeen times heavier than the molecule of hydrogen. this is what we more concisely express by saying "the molecular weight of oxygen is ," or "the molecular weight of ammonia is ," etc., etc. now, we wish to determine the _atomic weight_ of oxygen; that is, we wish to find how many times the oxygen atom is heavier than the atom of hydrogen. we make use of avogadro's law and of the definition of "atom" which has been deduced from it (see p. ). we know that eight parts by weight of oxygen combine with one part by weight of hydrogen to form water; but we do not know whether the molecule of water contains one atom of each element, or two atoms of hydrogen and one atom of oxygen, or some other combination of these atoms (see p. ). but by vaporizing water and weighing the gas so produced, we find that water vapour is nine times heavier than hydrogen: now, : = : , therefore the molecular weight of water gas is . analysis tells us that eighteen parts by weight of water gas contain sixteen parts of oxygen and two parts of hydrogen; that is to say, we now know that in the molecule of water gas there are two atoms of hydrogen combined with sixteen parts by weight of oxygen. we now proceed to analyze and determine the molecular weights of as many gaseous compounds of oxygen as we can obtain. the outcome of all is that we have as yet failed to obtain any such compound in the molecule of which there are less than sixteen parts by weight of oxygen. in some of these molecules there are sixteen, in some thirty-two, in some forty-eight, in some sixty-four parts by weight of oxygen, but in none is there less than sixteen parts by weight of this element. therefore we conclude that the atomic weight of oxygen is , because this is the smallest amount, referred to hydrogen taken as , which has hitherto been found in the molecule of any compound of oxygen. the whole of the work done since the publication of dalton's "new system" has emphasized the importance of that chemist's remark, that no safe conclusion can be drawn as to the value of the atomic weight of an element except from a consideration of many compounds of that with other elements. but in avogadro's law we have a far more accurate and trustworthy method for determining the molecular weights of compounds than any which dalton was able to devise by his study of chemical combinations. we have thus got a clearer conception of "atom" than was generally possessed by chemists in the days of dalton, and this we have gained by introducing the further conception of "molecule" as that of a quantity of matter different from, and yet similar to, the atom. the task now before us will for the most part consist in tracing the further development of the fundamental conception of dalton, the conception, viz., of each chemical substance as built up of small parts possessing all the properties, other than the mass, of the whole; and--what we also owe to dalton--the application of this conception to explain the facts of chemical combination. * * * * * the circumstances of dalton's early life obliged him to trust largely to his own efforts for acquiring knowledge; and his determination not to accept facts at second hand but to acquire them for himself, is very marked throughout the whole of his life. in the preface to the second part of the "new system" he says, "having been in my progress so often misled by taking for granted the results of others, i have determined to write as little as possible but what i can attest by my own experience." we should not expect such a man as this to make any great use of books; one of his friends tells us that he heard him declare on a public occasion that he could carry his library on his back, and yet had not read half of the books which comprised it. the love of investigation which characterized dalton when young would naturally be increased by this course of intellectual life. how strong this desire to examine everything for himself became, is amusingly illustrated by a story told by his medical adviser, dr. ransome. once when dalton was suffering from catarrh dr. ransome had prescribed a james's powder, and finding his patient much better next day, he congratulated himself and dalton on the good effects of the medicine. "i do not well see how that can be," said dalton, "as i kept the powder until i could have an opportunity of analyzing it." as dalton grew older he became more than ever disinclined to place much trust in the results obtained by other naturalists, even when these men were acknowledged to be superior to himself in manipulative and experimental skill. thus, as we have already learned, he could not be brought to allow the truth of gay-lussac's experimentally established law regarding gaseous combinations; he preferred to attribute gay-lussac's results to errors of experiment. "the truth is, i believe, that gases do not unite in equal or exact measures in any one instance; when they appear to do so it is owing to the inaccuracy of our experiments." that dalton did not rank high as an experimenter is evident from the many mistakes in matters of fact which are to be found in the second part of his "new system." a marked example of his inaccuracy in purely experimental work is to be found in the supposed proof given by him that charcoal, after being heated to redness, does not absorb gases. he strongly heated a quantity of charcoal, pulverized it, and placed it in a florence flask, which was connected by means of a stopcock with a bladder filled with carbonic acid: after a week he found that the flask and its contents had not sensibly increased in weight, and he concluded that no carbonic acid had been absorbed by the charcoal. but no trustworthy result could be obtained from an experiment in which the charcoal, having been deprived of air by heating, was again allowed to absorb air by being pulverized in an open vessel, and was then placed in a flask filled with air, communication between the carbonic acid and the external air being prevented merely by a piece of bladder, a material which is easily permeated by gases. dalton used a method which can only lead to notable results in natural science when employed by a really great thinker; he acquired a few facts, and then thought out the meaning of these. almost at the beginning of each investigation he tried to get hold of some definite generalization, and _then_ he proceeded to amass special facts. the object which he kept before himself in his experimental work was to establish or to disprove this or that hypothesis. every experiment was conducted with a clearly conceived aim. he was even willing to allow a large margin for errors of experiment if he could thereby bring the results within the scope of his hypothesis. that the _law of multiple proportions_ is simply a generalization of facts, and may be stated apart from the atomic theory, is now generally admitted. but in dalton's mind this law seems to have arisen rather as a deduction from the theory of atoms than to have been gained as a generalization from experiments. he certainly always stated this law in the language of the atomic theory. in one of his walking excursions he explained his theory to a friend, and after expounding his views regarding atomic combinations, he said that the examples which he had given showed the necessary existence of the principle of multiple proportions: "thou knowest it must be so, for no man can split an atom." we have seen that carburetted hydrogen was one of the compounds on the results of the analysis of which he built his atomic theory; yet we find him saying of the constitution of this compound that "no correct notion seems to have been formed till the atomic theory was introduced and applied in the investigation." when dalton was meditating on the laws of chemical combination, a french chemist, m. proust, published analyses of metallic oxides, which proved that when a metal forms two oxides the amount of metal in each is a fixed quantity--that there is a sudden jump, as it were, from one oxide to another. we are sometimes told that from these experiments proust would have recognized the law of multiple proportions had his analyses only been more accurate; but we know that dalton's analyses were very inaccurate, and yet he not only recognized the law of multiple proportions, but propounded and established the atomic theory. something more than a correct system of keeping books and balancing accounts is wanted in natural science. dalton's experimental results would be the despair of a systematic analyst, but from these dalton's genius evolved that splendid theory which has done so much to advance the exact investigation of natural phenomena. probably no greater contrast could be found between methods of work, both leading to the establishment of scientific (that is, accurate and precise) results, than that which exists between the method of dalton and the method pursued by priestley. priestley commenced his experiments with no particular aim in view; sometimes he wanted to amuse himself, sometimes he thought he might light upon a discovery of importance, sometimes his curiosity incited him to experiment. when he got facts he made no profound generalizations; he was content to interpret his results by the help of the prevailing theory of his time. but each new fact only spurred him on to make fresh incursions into the fields of nature. dalton thought much and deeply; his experimentally established facts were to him symbols of unseen powers. he used facts as hobbes says the wise man uses words: they were his counters only, not his money. when we ask how it was that dalton acquired his great power of penetrating beneath the surface of things and finding general laws, we must attribute this power in part to the training which he gave himself in physical science. it was from a consideration of physical facts that he gained the conception of ultimate particles of definite weight. his method was essentially dynamical; that is, he pictured a gas as a mass of little particles, each of which acted on and was acted on by, other particles. the particles were not thrown together anyhow; definite forces existed between them. each elementary or compound gas was pictured as a system of little particles, and the properties of that gas were regarded as dependent on the nature and arrangement of these particles. such a conception as this could only be gained by a careful and profound thinker versed in the methods of physical and mathematical science. thus we see that although dalton appeared to gain his great chemical results by a method which we are not generally inclined to regard as the method of natural science, yet it was by virtue of his careful training in a branch of knowledge which deals with facts, as well as in that science which deduces particular conclusions from general principles, that he was able to introduce his fruitful conceptions into the science of chemistry. to me it appears that dalton was pre-eminently distinguished by the possession of imagination. he formed clear mental images of the phenomena which he studied, and these images he was able to combine and modify so that there resulted a new image containing in itself all the essential parts of each separate picture which he had previously formed. from his intense devotion to the pursuit of science the development of dalton's general character appears to have been somewhat dwarfed. although he possessed imagination, it was the imagination of a naturalist rather than that of a man of broad culture. perhaps it was a want of broad sympathies which made him trust so implicitly in his own work and so readily distrust the work of others, and which moreover led him astray in so many of his purely experimental investigations. * * * * * dalton began his chemical work about six years after the death of lavoisier. unlike that great philosopher he cared nothing for political life. the friends in whose family he spent the greater part of his life in manchester were never able to tell whether he was whig or tory. unlike priestley he was content to let metaphysical and theological speculation alone. in his quiet devotion to study he more resembled black, and in his method, which was more deductive than that usually employed in chemistry, he also resembled the edinburgh professor. trained from his earliest days to depend on himself, nurtured in the creedless creed of the friends, he entered on his life's work with few prejudices, if without much profound knowledge of what had been done before him. by the power of his insight into nature and the concentration of his thought, he drew aside the curtain which hung between the seen and the unseen; and while herschel, sweeping the heavens with his telescope and night by night bringing new worlds within the sphere of knowledge, was overpowering men's minds by new conceptions of the infinitely great, john dalton, with like imaginative power, was examining the architecture of the ultimate particles of matter, and revealing the existence of law and order in the domain of the infinitely small. footnotes: [ ] see fig. , which is copied from the original in the "new system of chemical philosophy," and illustrates dalton's conception of a quantity of carbonic acid gas, each atom built up of one atom of carbon and two of oxygen; of nitrous oxide gas, each atom composed of one atom of nitrogen and one of oxygen; and of hydrogen gas, constituted of single atoms. [ ] more accurate analysis has shown that there are six parts of carbon united respectively with one and with two parts by weight of hydrogen in these compounds. chapter iv. establishment of general principles of chemical science (_continued_)--period of davy and berzelius. _humphry davy_, - . _johann jacob berzelius_, - . we may roughly date the period of chemical advance during which the connections between chemistry and other branches of natural knowledge were recognized and studied, as beginning with the first year of this century, and as continuing to our own day. the elaboration of the atomic theory was busily carried on during the second and third decades of this century; to this the labour of the swedish chemist berzelius largely contributed. that there exist many points of close connection between chemical and electrical science was also demonstrated by the labours of the same chemist, and by the brilliant and impressive discoveries of sir humphry davy. a system of classification of chemical elements and compounds was established by the same great naturalists, and many inroads were made into the domain of the chemistry of bodies of animal and vegetable origin. the work of berzelius and davy, characterized as it is by thoroughness, clearness and definiteness, belongs essentially to the modern era of chemical advance; but i think we shall better preserve the continuity of our story if we devote a chapter to a consideration of the work of these two renowned naturalists before entering on our review of the time immediately preceding the present, as typical workers in which time i have chosen liebig and dumas. in the last chapter we found that the foundations of the atomic theory had been laid, and the theory itself had been applied to general problems of chemical synthesis, by dalton. in giving, in that chapter, a short sketch of the modern molecular theory, and in trying to explain the meaning of the term "molecule" as contrasted with "atom," i necessarily carried the reader forward to a time considerably later than the first decade of this century. we must now retrace our steps; and in perusing the account of the work of berzelius and davy given in the present chapter, the reader must endeavour to have in his mind a conception of atom analogous to the mental picture formed by dalton (see pp. , ); he must regard the term as applicable to element and compound alike; he must remember that the work of which he reads is the work of those who are striving towards a clear conception of the atom, and who are gradually rising to a recognition of the existence of more than one order of small particles, by the regular putting together of which masses of matter are constituted. no materials, so far as i am aware, exist from which a life of berzelius can be constructed. i must therefore content myself with giving a mere enumeration of the more salient points in his life. of his chemical work abundant details are fortunately to be found in his own "lehrbuch," and in the works and papers of himself and his contemporaries. * * * * * johann jacob berzelius was the son of the schoolmaster of wäfersunda, a village near linköping, in east gothland, sweden. he was born in august --he was born, that is, a few years after priestley's discovery of oxygen; at the time when lavoisier had nearly completed his theory of combustion; when dalton was endeavouring to keep the unruly youth of eaglesfield in subjection; and when black, having established the existence of fixed air and the theory of latent heat, was the central figure in the band of students who were enlarging our knowledge of nature in the scottish capital. being left an orphan at the age of nine, the young berzelius was brought up by his grandfather, who appears to have been a man of education and sense. after attending school at linköping, he entered the university of upsala as a student of medicine. here he soon began to show a taste for chemistry. it would appear that few or no experiments were then introduced into his lectures by the professor of chemistry at upsala; little encouragement was given to pursue chemical experiments, and so berzelius had to trust to his own labours for gaining an acquaintance with practical chemistry. having thus made considerable progress in chemistry, and being on a visit to the mineral baths of medevi, he seized the opportunity to make a very thorough analysis of the waters of this place, which were renowned in sweden for their curative properties. the publication of this analysis marks the first appearance of berzelius as an author. he graduated as m.b. in , and a year or two later presented his dissertation, entitled "the action of galvanism on organic bodies," as a thesis for the degree of doctor of medicine. this thesis, like that of black, published about half a century earlier, marks an important stage in the history of chemistry. these and other publications made the young doctor famous; he was called to stockholm to be extraordinary (or assistant) professor of chemistry in the medical school of that capital. sometimes practising medicine in order to add to his limited income, but for the most part engaged in chemical research, he remained in stockholm for nearly fifty years, during most of which time the laboratory of berzelius in the swedish capital was regarded as one of the magnetic poles of the chemical world. to this point came many of the great chemists who afterwards enriched the science by their discoveries. wöhler, h. and g. rose, magnus, gmelin, mitscherlich and others all studied with berzelius. he visited england and france, and was on terms of intimacy and in correspondence with davy, dalton, gay-lussac, berthollet and the other men who at that period shed so much lustre on english and french science. it is said that berzelius was so much pleased with the lectures of dr. marcet at guy's hospital, that on his return from his visit to england in , he introduced much more liveliness and many more experimental illustrations into his own lectures. at the age of thirty-one, berzelius was chosen president of the stockholm academy of sciences; a few years later he was elected a foreign fellow of the royal society, which society bestowed on him the copley medal in . he was raised to the rank of a baron by the king of sweden, being allowed as a special privilege to retain his own name. in the year berzelius resigned his professorship, and in the same year he married. during the remainder of his life, he continued to receive honours of all kinds, but he never for a moment forsook the paths of science. after the death of davy, in , he was recognized as the leading european chemist of his age; but, although firm in his own theoretical views, he was ready to test these views by appealing to nature. the very persistency with which he clung to a conception established on some solid experimental basis insured that new light would be thrown on that conception by the researches of those chemists who opposed him. probably no chemist has added to the science so many carefully determined facts as berzelius; he was always at work in the laboratory, and always worked with the greatest care. yet the appliances at his command were what we should now call poor, meagre, and utterly inadequate. professor wöhler of göttingen, who in the fulness of days and honours has so lately gone from amongst us, recently gave an account of his visit to berzelius in the year . wöhler had taken his degree as doctor of medicine at heidelberg, and being anxious to prosecute the study of chemistry he was advised by his friends to spend a winter in the laboratory of the swedish professor. having written to berzelius and learned that he was willing to allow him working room in his laboratory, the young student set out for stockholm. after a journey to lübeck and a few days' passage in a small sailing-vessel, he arrived in the swedish capital. knocking at the door of the house pointed out as that of berzelius, he tells us that his heart beat hard as the door was opened by a tall man of florid complexion. "it was berzelius himself," he exclaims. scarcely believing that he was in the very room where so many famous discoveries had been made, he entered the laboratory. no water, no gas, no draught-places, no ovens were to be seen; a couple of plain tables, a blowpipe, a few shelves with bottles, a little simple apparatus, and a large water-barrel whereat anna, the ancient cook of the establishment, washed the laboratory dishes, completed the furnishings of this room, famous throughout europe for the work which had been done in it. in the kitchen which adjoined, and where anna cooked, was a small furnace and a sand bath for heating purposes. in this room many great discoveries were made. among these we may note the separation of the element columbium in , and of selenion in ; the discovery of the new earth thoria in ; the elucidation of the properties of yttrium and cerium about , of uranium in , and of the platinum metals in ; the accurate determination of the atomic weights of the greater number of the elements; the discovery of "sulphur salts" in - , and the proof that silica is an acid, and that most of the "stony" minerals are compounds of this acid with various bases. but we shall better learn the value of some of these discoveries by taking a general review of the contributions to chemical science of the man who spent most of his life at work in that room in stockholm. the german chemist richter, in the first or second year of this century, had drawn attention to the fact that when two neutral compounds, such as nitrate of potash and chloride of lime, react chemically, the substances produced by this reaction are also neutral. all the potash combined with nitric acid in one salt changes places with all the lime combined with muriatic acid in the other salt; therefore, said richter, these different quantities of potash and lime are neutralized by the same quantity of nitric acid; and, hence, these amounts of potash and lime are chemically _equivalent_, because these are the amounts which perform the same reaction, viz. neutralization of a fixed quantity of acid. if then careful analyses were made of a number of such neutral compounds as those named, the _equivalents_ of all the commoner "bases" and "acids"[ ] might be calculated. richter's own determinations of the equivalents of acids and bases were not very accurate, but berzelius was impressed with the importance of this work. the year before the appearance of dalton's "new system" (_i.e._ in ), he began to prepare and carefully analyze series of neutral salts. as the work was proceeding he became acquainted with the theory of dalton, and at once saw its extreme importance. for some time berzelius continued to work on the lines laid down by dalton, and to accumulate data from which the atomic weights of elements might be calculated; but he soon perceived--as the founder of the theory had perceived from the very outset--that the fundamental conception of each atom of an element as being a distinct mass of matter weighing more or less than the atom of every other element, and of each atom of a compound as being built up of the atoms of the elements which compose that compound,--berzelius, i say, perceived that these conceptions must remain fruitless unless means were found for determining the number of elementary atoms in each compound atom. we have already learned the rules framed by the founder of the atomic theory for his guidance in attempting to solve this problem. berzelius thought those rules insufficient and arbitrary; he therefore laid down two general rules, on the lines of which he prosecuted his researches into chemical synthesis. "one atom of one element combines with one, two, three, or more atoms of another element." this is practically the same as dalton's definitions of binary, ternary, etc., compounds (p. ). "two atoms of one element combine with three and five atoms of another element." berzelius here recognizes the existence of compound atoms of a more complex structure than any of those recognized by dalton. berzelius further extended the conception of atom by applying it to groups of elements formed, according to him, by the combination of various compound atoms. to his mind every compound atom appeared as built up of two parts; each of these parts might be an elementary atom, or might be itself built up of several elementary atoms, yet in the berzelian theory each acted as a definite whole. so far as the building up of the complex atom went, each of the two parts into which this atom could be divided acted as if it were a simple atom. if we suppose a patch of two shades of red colour to be laid on a smooth surface, and alongside of this a patch of two shades of yellow colour, and if we suppose the whole mass of colour to be viewed from a distance such that one patch appears uniformly red and the other uniformly yellow, we shall have a rough illustration of the berzelian compound atom. to the observer the whole mass of colour appears to consist of two distinct patches of contrasted colours; but let him approach nearer, and he perceives that what appeared to be a uniform surface of red or yellow really consists of two patches of unlike shades of red or of yellow. the whole mass of colour represents the compound atom; broadly it consists of two parts--the red colour represents one of the constituent atoms, the yellow colour represents the other constituent atom; but on closer examination the red atom, so to speak--and likewise the yellow atom--is found to consist of parts which are less unlike each other than the whole red atom is unlike the whole yellow atom. we shall have to consider in more detail the reasoning whereby berzelius arrived at this conception of every compound atom as a _dual_ structure (see pp. - ). at present i wish to notice this conception as lying at the root of most of the work which he did in extending and applying the daltonian theory. i wish to insist on the fact that the atomic theory could not advance without methods being found for determining the number of elementary atoms in a compound atom, without clear conceptions being gained of every compound atom as a structure, and without at least attempts being made to learn the laws in accordance with which that structure was built. before the atomic weight of oxygen could be determined it was necessary that the number of oxygen and of hydrogen atoms in the atom of water should be known; otherwise all that could be stated was, the atomic weight of oxygen is a simple multiple of . berzelius did much to advance chemical science by the introduction and application of a few simple rules whereby he determined the number of elementary atoms in various compound atoms. but as the science advanced, and as more facts came to be known, the berzelian rules were found to be too narrow and too arbitrary; chemists sought for some surer and more generally applicable method than that which berzelius had introduced, and the imperious demand for this method at last forced them to recognize the importance of the great generalization of the italian naturalist avogadro, which they had possessed since the year , but the meaning of which they had so long failed to understand. berzelius made one great step in the direction of recognizing avogadro's distinction between atom and molecule when he accepted gay-lussac's generalization that "equal volumes of gases contain equal numbers of atoms:" but he refused to apply this to other than elementary gases. the weights of the volumes of elementary gases which combined were, for berzelius, also the weights of the atoms of these elements. thus, let the weight of one volume of hydrogen be called , then two volumes of hydrogen, weighing , combine with one volume of oxygen, weighing , to form two volumes of water vapour; therefore, said berzelius, the atom of water consists of two atoms of hydrogen and one atom of oxygen, and the atom of the latter element is sixteen times heavier than the atom of the former. three volumes of hydrogen, weighing , combine with one volume of nitrogen, weighing , to form two volumes of ammonia; therefore, said berzelius, the atom of ammonia consists of three atoms of hydrogen combined with one atom of nitrogen, and the nitrogen atom is fourteen times heavier than the atom of hydrogen. while berzelius was applying these rules to the determination of the atomic weights of the elements, and was conducting the most important series of analyses known in the annals of the science, two great physico-chemical discoveries were announced. in the year the "_law of isomorphism_" was stated by mitscherlich: "compounds the atoms of which contain equal numbers of elementary atoms, similarly arranged, have the same crystalline form." as thus stated, the law of isomorphism affirms that if two compounds crystallize in the same form, the atoms of these compounds are built up of the same number of elementary atoms--however different may be the nature of the elements in the compounds--and that these elementary atoms are similarly arranged. this statement was soon found to be too absolute, and was accordingly modified; but to go into the history of the law of isomorphism would lead us too far from the great main path of chemical advance, the course of which we are seeking to trace. berzelius at once accepted mitscherlich's law, as an aid in his researches on atomic weights. the help to be derived from this law may be illustrated thus: let us assume that two compounds have been obtained exhibiting identity of crystalline form; let it be further assumed that the number of elementary atoms in the atom of one of these compounds is known; it follows, by the law of isomorphism, that the number of elementary atoms in the atom of the other is known also. let the two compounds be _sulphate of potash_ and _chromate of potash_; let it be assumed that the atom of the first named is known to consist of two atoms of potassium, one atom of sulphur, and four atoms of oxygen; and that the second substance is known to be a compound of the elements potassium, chromium and oxygen; then the atom of the second compound contains, by mitscherlich's law, two atoms of potassium, one atom of chromium and four atoms of oxygen: hence the relative weight of the atom of chromate of potash can be determined, and hence the relative weight of the atom of chromium can also be determined. a year after the announcement of mitscherlich's law, the following generalization was stated to hold good, by two french naturalists, dulong and petit:--"the atoms of all solid elements have the same capacity for heat." if the amount of heat required to raise the temperature of one grain of water through one degree be called _one unit of heat_, then the capacity for heat of any body other than water is the number of units of heat required to raise the temperature of one grain of that substance through one degree. each chemical substance, elementary and compound, has its own capacity for heat; but, instead of comparing the capacities for heat of equal weights, dulong and petit compared the capacities for heat of weights representing the weights of the atoms of various elements. thus, equal amounts of heat are required to raise, through the same interval of temperature, fifty-six grains of iron, one hundred and eight grains of silver, and sixty-three and a half grains of copper; but the weights of the atoms of these three elements are in the proportion of : : - / . dulong and petit based their generalization on measurements of the capacities for heat of thirteen elements; further research has shown that their statement most probably holds good for all the solid elements. here then was a most important instrument put into the hands of the chemist. it is only necessary that the atomic weight of one solid element should be certainly known, and that the amount of heat required to raise through one degree the number of grains of that element expressed by its atomic weight should also be known; then the number which expresses the weight, in grains, of any other solid element which is raised through one degree by the same amount of heat, likewise expresses the relative weight of the atom of that element. thus, suppose that the atomic weight of silver is known to be , and suppose that six units of heat are required to raise the temperature of one hundred and eight grains of this metal through one degree; then suppose it is found by experiment that six units of heat suffice to raise the temperature of two hundred and ten grains of bismuth through one degree, it follows--according to the law of dulong and petit--that is the atomic weight of bismuth. the modified generalization of gay-lussac--"equal volumes of _elementary_ gases contain equal numbers of atoms;" the laws of "isomorphism" and of "atomic heat;" and the two empirical rules stated on p. ;--these were the guides used by berzelius in interpreting the analytical results which he and his pupils obtained in that memorable series of researches, whereby the conceptions of dalton were shown to be applicable to a wide range of chemical phenomena. the fixity of composition of chemical compounds has now been established; a definite meaning has been given to the term "element;" the conception of "atom" has been gained, but much remains to be done in the way of rendering this conception precise; and fairly good, but not altogether satisfactory methods have been introduced by which the relative weights of the atoms of elements and compounds may be determined. at this time chemists are busy preparing and describing new compounds, and many new elements are also being discovered; the need of classification begins to be felt more and more. in the days of berzelius and davy strenuous efforts were made to obtain some generalizations by the application of which the many known elements and compounds might be divided into groups. it was felt that a classification might be founded on the composition of compounds, or perhaps on the properties of the same compounds. these two general principles served as guides in most of the researches then instituted; answers were sought to these two questions: of what elements is this compound composed? and, what can this compound do; how does it react towards other bodies? lavoisier, as we know, regarded oxygen as the characteristic element of all _acids_. this term _acid_ implies the possession, by all the substances denoted by it, of some common property; let us shortly trace the history of this word in chemistry. vinegar was known to the greeks and romans, and the names which they gave this substance tell us that sourness was to them its characteristic property. they knew that vinegar effervesced when brought into contact with chalky earths, and that it was able to dissolve many substances--witness the story of cleopatra's draught of the pearl dissolved in vinegar. other substances possessed of these properties--for instance oil of vitriol and spirits of salt--as they became known, were classed along with vinegar; but no attempts were made to clearly define the properties of these bodies till comparatively recent times. the characteristics of an acid substance enumerated by boyle are--solvent power, which is exerted unequally on different bodies; power of turning many vegetable blues to red, and of restoring many vegetable colours which had been destroyed by alkalis; power of precipitating solid sulphur from solutions of this substance in alkalis, and the power of acting on alkalis to produce substances without the properties of either acid or alkali. but what, one may ask, is an alkali, of which mention is so often made by boyle? from very early times it had been noticed that the ashes which remained when certain plants were burned, and the liquid obtained by dissolving those ashes in water, had great cleansing powers; that they removed oily matter, fat and dirt from cloth and other fabrics. the fact that an aqueous solution of these ashes affects the coloured parts of many plants was also noticed in early times. as progress was made in chemical knowledge observers began to contrast the properties of this plant-ash with the properties of acids. the former had no marked taste, the latter were always very sour; the former turned some vegetable reds to blue, the latter turned the blues to red; a solution of plant-ash had no great solvent action on ordinary mineral matter, whereas this matter was generally dissolved by an acid. in the time of the alchemists, who were always seeking for the principles or essences of things, these properties of acids were attributed to _a principle of acidity_, while the properties of plant-ash and substances resembling plant-ash were attributed to a _principle of alkalinity_ (from arabic _alkali_, or _the ash_). in the seventeenth century the distinction between acid and alkali was made the basis of a system of chemical medicine. the two principles of acidity and alkalinity were regarded as engaged in an active and never-ending warfare. every disease was traced to an undue preponderance of one or other of these principles; to keep these unruly principles in quietness became the aim of the physician, and of course it was necessary that the physician should be a chemist, in order that he might know the nature and habits of the principles which gave him so much trouble. up to this time the term "alkali" had been applied to almost any substance having the properties which i have just enumerated; but this group of substances was divided by van helmont and his successors into _fixed alkali_ and _volatile alkali_, and fixed alkali was further subdivided into _mineral alkali_ (what we now call soda) and _vegetable alkali_ (potash). about the same time acids were likewise divided into three groups; _vegetable_, _animal_, and _mineral acids_. to the properties by which alkali was distinguished, viz. cleansing power and action on vegetable colouring matters, stahl (the founder of the phlogistic theory) added that of combining with acids. when an acid (that is, a sour-tasting substance which dissolves most earthy matters and turns vegetable blues to red) is added to an alkali (that is, a substance which feels soap-like to the touch, which does not dissolve many earthy matters, and which turns many vegetable reds to blue) the properties of both acid and alkali disappear, and a new substance is produced which is not characterized by the properties of either constituent. the new substance, as a rule, is without action on earthy matters or on vegetable colours; it is not sour, nor is it soapy to the touch like alkali; it is _neutral_. it is _a salt_. but, although stahl stated that an alkali is a substance which combines with an acid, it was not until a century later that these three--alkali, acid, salt--were clearly distinguished. but the knowledge that a certain group of bodies are sour and dissolve minerals, etc., and that a certain other group of bodies are nearly tasteless and do not dissolve minerals, etc., was evidently a knowledge of only the outlying properties of the bodies; it simply enabled a term to be applied to a group of bodies, which term had a definite connotation. _why_ are acids acid, and _why_ are alkalis alkaline? acids are acid, said becher (latter part of seventeenth century), because they all contain the same principle, viz. the primordial acid. this primordial acid is more or less mixed with earthy matter in all actual acids; it is very pure in spirits of salt. alkalis are alkaline, said basil valentine (beginning of the sixteenth century), because they contain a special kind of matter, "the matter of fire." according to other chemists (_e.g._ j. f. meyer, ), acids owe their acidity to the presence of a sharp or biting principle got from fire. acids, alkalis and salts _all_ contain, according to stahl (beginning of the eighteenth century), more or less _primordial acid_. the more of this a substance contains, the more acid it is; the less of this it contains, the more alkaline it is. all these attempted explanations recognize that similar properties are to be traced to similarity of composition; but the assertion of the existence of a "primordial acid," or of "the matter of fire," although undoubtedly a step in advance, was not sufficiently definite (unless it was supplemented by a distinct account of the properties of these principles) to be accepted when chemical knowledge became accurate. the same general consideration, founded on a large accumulation of facts, viz. that similarity of properties is due to similarity of composition, guided lavoisier in his work on acids. he found the "primordial acid" of stahl, and the "biting principle" of meyer, in the element oxygen. i have already (p. ) shortly traced the reasoning whereby lavoisier arrived at the conclusion that oxygen is _the acid-producer_; here i would insist on the difference between his method and that of basil valentine, stahl and the older chemists. _they_ carried into the domain of natural science conceptions obtained from, and essentially belonging to the domain of metaphysical or extra-physical speculation; _he_ said that oxygen is the acidifier, because all the compounds of this element which he actually examined were possessed of the properties included under the name acid. we know that lavoisier's conclusion was erroneous, that it was not founded on a sufficiently broad basis of facts. the conception of an acidifying principle, although that principle was identified with a known element, was still tainted with the vices of the alchemical school. we shall see immediately how much harm was done by the assertion of lavoisier, "all acids contain oxygen." in chapter ii. (pp. - ) we traced the progress of knowledge regarding alkalis from the time when the properties of these bodies were said to be due to the existence in them of "matter of fire," to the time when black had clearly distinguished and defined caustic alkali and carbonated alkali. the truly philosophical character, and at the same time the want of enthusiasm, of black become apparent if we contrast his work on alkali with that of lavoisier on acid. black did not hamper the advance of chemistry by finding a "principle of alkalinity;" but neither did he give a full explanation of the fact that certain bodies are alkaline while others are not. he set himself the problem of accurately determining the differences in composition between burnt (or caustic) and unburnt (or mild) alkali, and he solved the problem most successfully. he showed that the properties of mild alkalis differ from those of caustic alkalis, because the composition of the former differs from that of the latter; and he showed exactly wherein this difference of composition consists, viz. in the possession or non-possession of fixed air. strange we may say that this discovery did not induce black to prosecute the study of caustic alkalis: surely he would have anticipated davy, and have been known as the discoverer of potassium and sodium. in the time of stahl the name "salt" was applied, as we have learned, to the substance produced by the union of an acid with an alkali; but the same word was used by the alchemists with an altogether different signification. originally applied to the solid matter obtained by boiling down sea-water, and then extended to include all substances which, like this solid matter, are very easily dissolved by water and can be recovered by boiling down this solution, "salt" was, in the sixteenth and seventeenth centuries, the name given to one of the hypothetical principles or elements. many kinds of matter were known to be easily dissolved by water; the common possession of these properties was sought to be accounted for by saying that all these substances contained the same principle, namely, _the principle of salt_. i have already tried to indicate the reasoning whereby boyle did so much to overthrow this conception of salt. he also extended our knowledge of special substances which are now classed as salts. the chemists who came after boyle gradually reverted to the older meaning of the term "salt," adopting as the characteristics of all substances placed in this class, ready solubility in water, fusibility, or sometimes volatility, and the possession of a taste more or less like that of sea-salt. substances which resembled salts in general appearance, but were insoluble in water, and very fixed in the fire, were called "earths"; and, as was generally done in those days, the existence of a primordial earth was assumed, more or less of which was supposed to be present in actual earths. this recognition of the possibility of more or less of the primordial earth being present in actually occurring earths, of course necessitated the existence of various kinds of earth. the earths were gradually distinguished from each other; lime was recognized as a substance distinct from baryta, baryta as distinct from alumina, etc. stahl taught that one essential property of an earth was fusibility by fire, with production of a substance more or less like glass. this property was possessed in a remarkable degree by quartz or silica. hence silica was regarded as the typical earth, until berzelius, in , proved it to be an acid. but the earths resembled alkalis, inasmuch as they too combined with, and so neutralized, acids. there is an alkali hidden in every earth, said some chemists. an alkali is an earth refined by the presence of acid and combustible matter, said others. earths thus came to be included in the term "alkali," when that term was used in its widest acceptation. but a little later it was found that some of the earths were thrown down in the solid form from their solutions in acids by the addition of alkalis; this led to a threefold division, thus-- earths <----> alkaline earths <----> alkalis insoluble somewhat soluble very soluble in in water. in water. water. the distinction at first drawn between "earth" and "alkali" was too absolute; the intermediate group of "alkaline earths" served to bridge over the gap between the extreme groups. "in nature," says wordsworth, "everything is distinct, but nothing defined into absolute independent singleness." at this stage of advance, then, an earth is regarded as differing from an alkali in being insoluble, or nearly insoluble in water; in not being soapy to the touch, and not turning vegetable reds to blue: but as resembling an alkali, in that it combines with and neutralizes an acid; and the product of this neutralization, whether accomplished by an alkali or by an earth, is called a salt. to the earth or alkali, as being the foundation on which the salt is built, by the addition of acid, the name of _base_ was given by rouelle in . but running through every conception which was formed of these substances--acid, alkali, earth, salt--we find a tendency, sometimes forcibly marked, sometimes feebly indicated, but always present, to consider salt as a term of much wider acceptation than any of the others. an acid and an alkali, or an acid and an earth, combine to form a salt; but the salt could not have been thus produced unless the acid, the alkali and the earth had contained in themselves some properties which, when combined, form the properties of the salt. the acid, the alkali, the earth, each is, in a sense, a salt. the perfect salt is produced by the coalescence of the saltness of the acid with the saltness of the alkali. this conception finds full utterance in the names, once in common use, of _sal acidum_ for acid, _sal alkali_ for alkali, and _sal salsum_ or _sal neutrum_ for salt. all are salts; at one extreme comes that salt which is marked by properties called acid properties, at the other extreme comes the salt distinguished by alkaline properties, and between these, and formed by the union of these, comes the middle or neutral salt. it is thus that the nomenclature of chemistry marks the advances made in the science. "what's in a name?" to the historical student of science, almost everything. we shall find how different is the meaning attached in modern chemistry to these terms, _acid salt_, _alkaline salt_, _neutral salt_, from that which our predecessors gave to their _sal acidum_, _sal alkali_, and _sal neutrum_. we must note the appearance of the term _vitriol_, applied to the solid salt-like bodies obtained from acids and characterized by a glassy lustre. by the middle of last century the vitriols were recognized as all derived from, or compounded of, sulphuric acid (oil of vitriol) and metals; this led to a subdivision of the large class of neutral salts into ( ) metallic salts produced by the action of sulphuric acid on metals, and ( ) neutral salts produced by the action of earths or alkalis on acids generally. to rouelle, a predecessor of lavoisier, who died four years before the discovery of oxygen, we owe many accurate and suggestive remarks and experiments bearing on the term "salt." i have already mentioned that it was he who applied the word "base" to the alkali or earth, or it might be metal, from which, by the action of acid, a salt is built up. he also ceased to speak of an acid as _sal acidum_, or of an alkali as _sal alkali_, and applied the term "salt" exclusively to those substances which are produced by the action of acids on bases. when the product of such an action was neutral--that is, had no sour taste, no soapy feeling to the touch, no action on vegetable colours, and no action on acids or bases--he called that product _a neutral salt_; when the product still exhibited some of the properties of acid, _e.g._ sourness of taste, he called it _an acid salt_; and when the product continued to exhibit some of the properties of alkali, _e.g._ turned vegetable reds to blue, he called it _an alkaline salt_. rouelle also proved experimentally that an acid salt contains more acid--relatively to the same amount of base--than a neutral salt, and that an alkaline salt contains more base--relatively to the same amount of acid--than a neutral salt; and he proved that this excess of acid, or of base, is chemically united to the rest of the salt--is, in other words, an essential part of the salt, from which it cannot be removed without changing the properties of the whole. but we have not as yet got to know why certain qualities connoted by the term "acid" can be affirmed to belong to a group of bodies, why certain other, "alkaline," properties belong to another group, nor why a third group can be distinguished from both of these by the possession of properties which we sum up in the term "earthy." surely there must be some peculiarity in the composition of these substances, common to all, by virtue of which all are acid. the atom of an acid is surely composed of certain elements which are never found in the atom of an alkali or an earth; or perhaps the difference lies in the number, rather than in the nature of the elements in the acid atoms, or even in the arrangement of the elementary atoms in the compound atom of acid, of alkali, and of earth. i think that our knowledge of salt is now more complete than our knowledge of either acid, alkali, or earth. we know that a salt is formed by the union of an acid and an alkali or earth; if, then, we get to know the composition of acids and bases (_i.e._ alkalis and earths), we shall be well on the way towards knowing the composition of salts. and now we must resume our story where we left it at p. . lavoisier had recognized oxygen as the acidifier; black had proved that a caustic alkali does not contain carbonic acid. up to this time metallic calces, and for the most part alkalis and earths also, had been regarded as elementary substances. lavoisier however proved calces to be compounds of metals and oxygen; but as some of those calces had all the properties which characterized earths, it seemed probable that all earths are metallic oxides, and if all earths, most likely all alkalis also. many attempts were made to decompose earths and alkalis, and to obtain the metal, the oxide of which the earth or the alkali was supposed to be. one chemist thought he had obtained a metal by heating the earth baryta with charcoal, but from the properties of his metal we know that he had not worked with a pure specimen of baryta, and that his supposed metallic base of baryta was simply a little iron or other metal, previously present in the baryta, or charcoal, or crucible which he employed. but if lavoisier's view were correct--if all bases contained oxygen--it followed that all salts are oxygen compounds. acids all contain oxygen, said lavoisier; this was soon regarded as one of the fundamental facts of chemistry. earths and alkalis are probably oxides of metals; this before long became an article of faith with all orthodox chemists. salts are produced by the union of acids and bases, therefore all salts contain oxygen: the conclusion was readily adopted by almost every one. when the controversy between lavoisier and the phlogistic chemists was at its height, the followers of stahl had taunted lavoisier with being unable to explain the production of hydrogen (or phlogiston as they thought) during the solution of metals in acids; but when lavoisier learned the composition of water, he had an answer sufficient to quell these taunts. the metal, said lavoisier, decomposes the water which is always present along with the acid, hydrogen is thus evolved, and the metallic calx or oxide so produced dissolves in the acid and forms a salt. if this explanation were correct--and there was an immense mass of evidence in its favour and apparently none against it--then all the salts produced by the action of acids on metals necessarily contained oxygen. the lavoisierian view of a salt, as a compound of a metallic oxide--or base--with a non-metallic oxide--or acid--seemed the only explanation which could be accepted by any reasonable chemist: in the early years of this century it reigned supreme. but even during the lifetime of its founder this theory was opposed and opposed by the logic of facts. in berthollet published an account of experiments on prussic acid,--the existence and preparation (from prussian blue) of which acid had been demonstrated three or four years before by the swedish chemist scheele--which led him to conclude this compound to be a true acid, but free from oxygen. in the same chemist studied the composition and properties of sulphuretted hydrogen, and pronounced this body to be an acid containing no oxygen. but the experiments and reasoning of berthollet were hidden by the masses of facts and the cogency of argument of the lavoisierian chemists. the prevalent views regarding acids and bases were greatly strengthened by the earlier researches of sir humphry davy, in which he employed the voltaic battery as an instrument in chemical investigation. let us now consider some of the electro-chemical work of this brilliant chemist. in the spring of the year the electrical battery, which had recently been discovered by volta, was applied by nicholson and carlisle to effect the decomposition of water. the experiments of these naturalists were repeated and confirmed by davy, then resident at bristol, who followed up this application of electricity to effect chemical changes by a series of experiments extending from to , and culminating in the bakerian lecture delivered before the royal society in the latter year. the history of davy's life during these years, years rich in results of the utmost importance to chemical science, will be traced in the sequel; meanwhile we are concerned only with the results of his chemical work. the first bakerian lecture of humphry davy, "on some chemical agencies of electricity," deserves the careful study of all who are interested in the methods of natural science; it is a brilliant example of the disentanglement of a complex natural problem. volta and others had subjected water to the action of a current of electricity, and had noticed the appearance of acid and alkali at the oppositely electrified metallic surfaces. according to some experimenters, the acid was nitrous, according to others, muriatic acid. one chemist asserted the production of a new and peculiar body which he called _the electric acid_. the alkali was generally said to be ammonia. when davy passed an electric current through distilled water contained in glass vessels, connected by pieces of moist bladder, cotton fibre, or other vegetable matters, he found that nitric and hydrochloric acids were formed in the water surrounding the positively electrified plate or pole, and soda around the negatively electrified pole, of the battery. when the same piece of cotton fibre was repeatedly used for making connection between the glass vessels, and was washed each time in dilute nitric acid, davy found that the production of muriatic acid gradually ceased; hence he traced the formation of this acid to the presence of the animal or vegetable substance used in the experiments. finding that the glass vessels were somewhat corroded, and that the greater the amount of corrosion the greater was the amount of soda making its appearance around the negative pole, he concluded that the soda was probably a product of the decomposition of the glass by the electric current; he therefore modified the experiment. he passed an electric current through distilled water contained in small cups of agate, previously cleaned by boiling in distilled water for several hours, and connected by threads of the mineral asbestos, chosen as being quite free from vegetable matter; alkali and acid were still produced. the experiment was repeated several times with the same apparatus; acid and alkali were still produced, but the alkali decreased each time. the only conclusion to be drawn was that the alkali came from the water employed. two small cups of gold were now used to contain the water; a very small amount of alkali appeared at the negative pole, and a little nitric acid at the positive pole. the quantity of acid slowly increased as the experiment continued, whereas the quantity of alkali remained the same as after a few minutes' action of the electric current. the production of alkali is probably due, said davy, to the presence in the water of some substance which is not removed by distillation in a glass retort. by boiling down in a silver dish a quantity of the water he had used, a very small amount of solid matter was obtained, which after being heated was distinctly alkaline. moreover when a little of this solid matter was added to the water contained in the two golden cups, there was a sudden and marked increase in the amount of alkali formed around the negative pole. another quantity of the water which he had used was again distilled in a silver retort, and a little of the distillate was subjected to electrolysis as before. no alkali appeared. a little piece of glass was placed in the water; alkali quickly began to form. davy thus conclusively proved that the alkali produced during the electrolysis (_i.e._ decomposition by the electric current) of water is not derived from the water itself, but from mineral impurities contained in the water, or in the vessel in which the water is placed during the experiment. but the production of nitric acid around the positive pole was yet to be accounted for. before further experiments could be made it was necessary that davy should form an hypothesis--that he should mentally connect the appearance of the nitric acid with some other phenomenon sufficient to produce this appearance; he could then devise experiments which would determine whether the connection supposed to exist between the two phenomena really did exist or not. now, of the constituents of nitric acid--nitrogen, hydrogen and oxygen--all except the first named are present in pure water; nitrogen is present in large quantity in the ordinary atmosphere. it was only necessary to assume that some of the hydrogen and oxygen produced during the electrolysis of water seized on and combined with some of the nitrogen in the air which surrounded that water, and the continual production of nitric acid during the whole process of electrolysis was explained. but how was this assumption to be proved or disproved? davy adopted a method frequently made use of in scientific investigations:--remove the assumed cause of a phenomenon; if the phenomenon ceases to be produced, the assumed cause is probably the real cause. davy surrounded the little gold cups containing the water to be electrolysed with a glass jar which he connected with an air-pump; he exhausted most of the air from the jar and then passed the electric current through the water. very little nitric acid appeared. he now again took out most of the air from the glass jar, admitted some hydrogen to supply its place, and again pumped this out. this process he repeated two or three times and then passed the electric current. _no_ acid appeared in the water. he admitted air into the glass vessel; nitric acid began to be produced. thus he proved that whenever air was present in contact with the water being electrolysed, nitric acid made its appearance, and when the air was wholly removed the acid ceased to be produced. as he had previously shown that the production of this acid was not to be traced to impurities in the water, to the nature of the vessel used to contain the water, or to the nature of the material of which the poles of the battery were composed, the conclusion was forced upon him that the production of nitric acid in the water, and the presence of ordinary air around the water invariably existed together; that if one of these conditions was present, the other was also present--in other words, that one was the cause of the other. the result of this exhaustive and brilliant piece of work is summed up by davy in these words: "it seems evident then that water, chemically pure, is decomposed by electricity into gaseous matter alone, into oxygen and hydrogen." from the effects of the electric current on glass, davy argued that other earthy compounds would probably undergo change under similar conditions. he therefore had little cups of gypsum made, in which he placed pure water, and passed an electric current through the liquid. lime was formed around the negative, and sulphuric acid around the positive pole. using similar apparatus, he proved that the electric current decomposes very many minerals into an earthy or alkaline base and an acid. picturing to himself the little particles of a salt as being split by the electric current each into two smaller particles, one possessed of acid and the other of alkaline properties, davy thought it might be possible to intercept the progress of these smaller particles, which he saw ever travelling towards the positive and negative poles of the battery. he accordingly connected these small glass vessels by threads of washed asbestos; in one of the outer vessels he placed pure water, in the other an aqueous solution of sulphate of potash, and in the central vessel he placed ammonia. the negative pole of the battery being immersed in the sulphate of potash, and the positive pole in the water, it was necessary for the particles of sulphuric acid--produced by the decomposition of the sulphate of potash--to travel through the ammonia in the central vessel before they could find their way to the positive pole. now, ammonia and sulphuric acid cannot exist in contact--they instantly combine to form sulphate of ammonia; the sulphuric acid particles ought therefore to be arrested by the ammonia. but the sulphuric acid made its appearance at the positive pole just as if the central vessel had contained water. it seemed that the mutual attraction ordinarily exerted between sulphuric acid and ammonia was overcome by the action of the electric current. ammonia would generally present an insuperable barrier to the progress of sulphuric acid, but the electrical energy appeared to force the acid particles over this barrier; they passed towards their goal as if nothing stood in their way. experiments are now multiplied by davy, and the general conclusion drawn is that "hydrogen, the alkaline substances, the metals and certain metallic oxides are attracted by negatively electrified metallic surfaces, and repelled by positively electrified metallic surfaces; and contrariwise, that oxygen and acid substances are attracted by positively electrified metallic surfaces, and repelled by negatively electrified metallic surfaces; and these attractive and repulsive forces are sufficiently energetic to destroy or suspend the usual operation of chemical affinity."[ ] to account for this apparent suspension of the ordinary chemical laws, davy supposes that chemical compounds are continually decomposed and re-formed throughout the liquid which is subjected to the electrical action. thus, in the experiment with water, ammonia and sulphate of potash, he supposes that the sulphuric acid and ammonia do combine in the central vessel to form sulphate of ammonia, but that this compound is again decomposed, by the electrical energy, into sulphuric acid--which passes on towards the positive pole--and ammonia--which remains in the central vessel--ready to combine with more sulphuric acid as that comes travelling onwards from its source in the vessel containing sulphate of potash to its goal in the vessel containing water. the eye of the philosopher had pierced beneath the apparent stability of the chemical systems which he studied. to his vision there appeared in those few drops of water and ammonia and sulphate of potash a never-ceasing conflict of contending forces; there appeared a continual shattering and rebuilding of the particles of which the masses were composed. the whole was at rest, the parts were in motion; the whole was constant in chemical composition, the composition of each particle was changed a thousand times in the minutest portion of every second. to the mind of davy, the electrolysis of every chemical compound was a new application of the great law established by newton--"to every action there is an equal and opposite reaction." each step made in chemical science since davy's time has but served to emphasize the universality of this principle of action and reaction, a principle which has been too much overlooked in the chemical text-books, but the importance of which recent researches are beginning to impress on the minds of chemists. it is the privilege of the philosophic student of nature to penetrate the veil with which she conceals her secrets from the vulgar gaze. to him are shown sights which "eye hath not seen," and by him are perceived sounds which "ear hath not heard." each drop of water is seen by him not only to be built up of myriads of small parts, but each particle is seen to be in motion; many particles are being decomposed into still smaller particles of matter, different in properties from the original particles, but as the original particles are at the same time being reproduced, the continued existence of the drop of water with the properties of water is to him the result of the mutual action and reaction of contending forces. he knows that rest and permanence are gained, not by the cessation of action, but by the continuance of conflict; he knows that in the realm of natural phenomena, stable equilibrium is the resultant of the action of opposite forces, and that complete decomposition occurs only when one force becomes too powerful or another becomes too weak. pursuing the train of thought initiated by the experiments which i have described, davy entered upon a series of researches which led him to consider every chemical substance as possessing definite electrical relations towards every other substance. "as chemical attraction between two bodies seems to be destroyed by giving one of them an electrical state different from that which it naturally possessed--that is, by bringing it into a state similar to the other--so it may be increased by exalting its natural energy." thus zinc, a metal easily oxidized, does not combine with oxygen when negatively electrified, whereas silver, a metal oxidized with difficulty, readily combines with oxygen when positively electrified. substances in opposite electrical states appear to combine chemically, and the greater the electrical difference the greater the readiness with which chemical combination is effected. electrical energy and chemical attraction or _affinity_ are evidently closely connected; perhaps, said davy, they are both results of the same cause. thus davy arrived at the conception of a system of bodies as maintained in equilibrium by the mutual actions and reactions of both chemical and electrical forces; by increasing either of these a change is necessarily produced in the other. under certain electrical conditions the bodies will exert no chemical action on one another, but such action may be started by changing these electrical conditions, or, on the other hand, by changes in the chemical relations of the bodies a change in the electrical relations may be induced. thus davy found that if plates of copper and sulphur are heated, the copper exhibits a positive and the sulphur a negative electrical condition; that these electrical states become more marked as temperature rises, until the melting point of sulphur is reached, when the copper and sulphur combine together chemically and produce sulphide of copper. when water is electrolysed, davy looked on the oppositely electrified metallic plates in the battery as striving to attain a state of equilibrium; the negatively electrified zinc strives to gain positive electricity from the copper, which strives to gain negative electricity from the zinc. the water he regarded as the carrier of these electricities, the one in this direction, the other in that. in thus acting as a carrier, the water is itself chemically decomposed, with production of hydrogen and oxygen; but this chemical rearrangement of some of the substances which composed the original system (of battery and water) involves a fresh disturbance of electrical energy, and so the process proceeds until the whole of the water is decomposed or the whole of the copper or zinc plate is dissolved in the battery. if the water were not chemically decomposed, davy thought that the zinc and copper in the battery would quickly attain the state of electrical equilibrium towards which they continually strive, and that the current would therefore quickly cease. davy thought that "however strong the natural electrical energies of the elements of bodies may be, yet there is every probability of a limit to their strength; whereas the powers of our artificial instruments seem capable of indefinite increase." by making use of a very powerful battery, he hoped to be able to decompose substances generally regarded as simple bodies. taking a wide survey of natural phenomena, he sees these two forces, which we call chemical and electrical, everywhere at work, and by their mutual actions upholding the material universe in equilibrium. in the outbreaks of volcanoes he sees the disturbance of this equilibrium by the undue preponderance of electrical force; and in the formation of complex minerals beneath the surface of the earth, he traces the action of those chemical attractions which are ever ready to bring about the combination of elements, if they are not held in check by the opposing influence of electrical energy. we shall see how the great and philosophical conception of davy was used by berzelius, and how, while undoubtedly gaining in precision, it lost much in breadth in being made the basis of a rigid system of chemical classification. davy's hope that the new instrument of research placed in the hands of chemists by volta would be used in the decomposition of supposed simple substances was soon to be realized. a year after the lecture "on some chemical agencies of electricity," davy was again the reader of the bakerian lecture; this year ( ) it was entitled, "on some new phenomena of chemical change produced by electricity, particularly the decomposition of the fixed alkalis; and the exhibition of the new substances which constitute their bases; and on the general nature of alkaline bodies." in his first experiments on the effect of the electrical current on potash and soda, davy used strong aqueous solutions of these alkalis, with the result that hydrogen and oxygen only were evolved. he then passed the current through melted potash kept liquid during the operation by the use of a spirit-lamp, the flame of which was fed with oxygen. much light was evolved, and a great flame appeared at the negative pole; on changing the direction of the current, "aeriform globules, which inflamed in the air, rose through the potash." on the th of october , a piece of potash was placed on a disc of platinum, which was made the negative pole of a very powerful battery; a platinum wire brought into contact with the upper surface of the potash served as the positive pole. when the current was passed, the potash became hot and soon melted; gas was evolved at the upper surface, and at the lower (negative) side "there was no liberation of elastic fluid, but small globules, having a high metallic lustre, and being precisely similar in visible characters to quicksilver appeared, some of which burst with explosion and bright flame as soon as they were formed, and others remained, and were merely tarnished, and finally covered by a white film which formed on their surfaces." when davy saw these metallic globules burst through the crust of fusing potash, we are told by one of his biographers, "he could not contain his joy, he actually bounded about the room in ecstatic delight; and some little time was required for him to compose himself sufficiently to continue the experiment." this was the culminating point of the researches in which he had been continuously engaged for about six years. his interest and excitement were intense; the bakerian lecture was written "on the spur of the occasion, before the excitement of the mind had subsided," yet, says his biographer--and we may well agree with him--"yet it bears proof only of the maturest judgment; the greater part of it is as remarkable for experimental accuracy as for logical precision." but "to every action there is an equal and opposite reaction:" immediately after the delivery of the lecture, davy was prostrated by a severe attack of illness, which confined him to bed for nine weeks, and was very nearly proving fatal. that the phenomenon just described was really the decomposition of potash, and the production of the metal of which this substance is an oxygenized compound, was proved by obtaining similar results whether plates of silver, copper, or gold, or vessels of plumbago, or even charcoal, were used to contain the potash, or whether the experiment was conducted in the air, or in a glass vessel from which air had been exhausted, or in glass tubes wherein the potash was confined by mercury. the decomposition of potash was followed within a few days by that of soda, from which substance metallic globules were obtained which took fire when exposed to the air. but the analysis of potash and soda was not sufficient for davy; he determined to accomplish the synthesis of these substances. for this purpose he collected small quantities of the newly discovered metals, by conducting the electrolysis of potash and soda under experimental conditions such that the metals, as soon as produced, were plunged under the surface of naphtha, a liquid which does not contain oxygen, and which protected them from the action of the surrounding air. a weighed quantity of each metal was then heated in a stream of pure dry oxygen, the products were collected and weighed, and it was found that solutions of these products in water possessed all the properties of aqueous solutions of potash and soda. the new metals were now obtained in larger quantity by davy, and their properties carefully determined by him; they were named _potassium_ and _sodium_ respectively. they were shown to possess all those properties which were generally accepted as characteristic of metal, except that of being heavy. the new metals were extremely light, lighter than water. for some time it was difficult to convince all chemists that a metal could be a very light substance. we are assured that a friend of davy, who was shown potassium for the first time, and was asked what kind of substance he supposed it to be, replied, "it is metallic, to be sure;" "and then, balancing it on his finger, he added in a tone of confidence, 'bless me, how heavy it is!'" davy argued that since the alkalis, potash and soda, were found to be oxygen compounds of metals, the earths would probably also be found to be metallic oxides. in the year he succeeded in decomposing the three earths, lime, baryta and strontia, and in obtaining the metals _calcium_, _barium_ and _strontium_, but not in a perfectly pure condition, or in any quantity. he also got evidence of the decomposition of the earths silica, alumina, zirconia and beryllia, by the action of powerful electric currents, but he did not succeed in obtaining the supposed metallic bases of these substances. so far davy's discoveries had all tended to confirm the generally accepted view which regarded alkalis and earths as metallic oxides. but we found that the outcome of these views was to regard all salts--and among these, of course, common salt--as oxygen compounds.[ ] acids were oxygen compounds, bases were oxygen compounds, and as salts were produced by the union of acids with bases, they, too, must necessarily be oxygen compounds. berthollet had thrown doubt on the universality of lavoisier's name "oxygen," _the_ acidifier, but he had not conclusively proved the existence of any acid which did not contain oxygen. the researches of davy naturally led him to consider the prevalent views regarding acids, bases and salts. muriatic (or as we now call it hydrochloric) acid had long been a stumbling-block to the thorough-going lavoisierian chemists. oxygen could not be detected in it, yet it ought to contain oxygen, because oxygen is the acidifier. of course, if muriatic acid contains oxygen, the salts--muriates--produced by the action of this acid on alkalis and earths must also contain oxygen. many years before this time the action of muriatic acid on manganese ore had been studied by the swedish chemist scheele, who had thus obtained a yellow-coloured gas with a very strong smell. berthollet had shown that when a solution of this gas in water is exposed to sunlight, oxygen is evolved and muriatic acid is produced. the yellow gas was therefore supposed to be, and was called, "oxidized muriatic acid," and muriatic acid was itself regarded as composed of oxygen and an unknown substance or _radicle_. in gay-lussac and thenard found that one volume of hydrogen united with one volume of the so-called oxidized muriatic acid to form muriatic acid; the presence of hydrogen in this acid was therefore proved. when davy began ( - ) to turn his attention specially to the study of salts, he adopted the generally accepted view that muriatic acid is a compound of oxygen and an unknown radicle, and that by the addition of oxygen to this compound oxidized muriatic acid is produced. but unless davy could prove the presence of oxygen in muriatic acid he could not long hold the opinion that oxygen was really a constituent of this substance. he tried to obtain direct evidence of the presence of oxygen, but failed. he then set about comparing the action of muriatic acid on metals and metallic oxides with the action of the so-called oxidized muriatic acid on the same substances. he showed that salt-like compounds were produced by the action of oxidized muriatic acid either on metals or on the oxides of these metals, oxygen being evolved in the latter cases; and that the same compounds and water were produced by the action of muriatic acid on the same metallic oxides. these results were most easily and readily explained by assuming the so-called oxidized muriatic acid to be an elementary substance, and muriatic acid to be a compound of this element with hydrogen. to the new element thus discovered--for he who establishes the elementary nature of a substance may almost be regarded as its discoverer--davy gave the name of _chlorine_, suggested by the yellow colour of the gas (from greek, = _yellow_). he at once began to study the analogies of chlorine, to find by experiment which elements it resembled, and so to classify it. many metals, he found, combined readily with chlorine, with evolution of heat and light. it acted, like oxygen, as a supporter of combustion; it was, like oxygen, attracted towards the negative pole of the voltaic battery; its compound with hydrogen was an acid; hence said davy chlorine, like oxygen, is a supporter of combustion and also an acidifier. but it was very hard to get chemists to adopt these views. as bacon says, "if false facts in nature be once on foot, what through neglect of examination, the countenance of antiquity, and the use made of them in discourse, they are scarce ever retracted." chemists had long been accustomed to systems which pretended to explain all chemical facts. the phlogistic theory, which had tyrannized over chemistry, had been succeeded by the lavoisierian chemistry, which recognized one acidifier, and this also the one supporter of combustion. to ascribe these properties to any element other than oxygen appeared almost profane. but when davy spoke of chlorine as an acidifier, he did not use this word in the same sense as that in which it was employed by the upholders of the oxygen theory of acids; he simply meant to express the fact that a compound containing chlorine as one of its constituents, but not containing oxygen, was a true acid. when gay-lussac attempted to prove that hydrogen is an _alkalizing principle_, davy said, "this is an attempt to introduce into chemistry a doctrine of occult qualities, and to refer to some mysterious and inexplicable energy what must depend upon a peculiar corpuscular arrangement." and with regard to gay-lussac's strained use of analogies between hydrogen compounds and alkalis, he says, "the substitution of analogy for fact is the bane of chemical philosophy; the legitimate use of analogy is to connect facts together, and to guide to new experiments." but davy's facts were so well established, and his experiments so convincing, that before two or three years had passed, most chemists were persuaded that chlorine was an element--_i.e._ a substance which had never been decomposed--and that muriatic acid was a compound of this element with hydrogen. berzelius was among the last to adopt the new view. wöhler tells us that in the winter of , when he was working in the laboratory of berzelius, anna, while washing some basins, remarked that they smelt strongly of oxidized muriatic acid: "now," said berzelius, "listen to me, anna. thou must no longer say 'oxidized muriatic acid,' but 'chlorine;' that is better." this work on chlorine was followed up, in , by the proof that the class of acidifiers and supporters of combustion contains a third elementary substance, viz. iodine. as davy's views regarding acids and salts became developed, he seems to have more and more opposed the assumption that any one element is especially to be regarded as the acidifying element; but at the same time he seems to admit that most, if not all, acids contain hydrogen. such oxides as sulphur trioxide, nitrogen pentoxide, etc., do not possess acid properties except in combination with water. but he of course did not say that all hydrogen compounds are acids; he rather regarded the possession by a substance of acid properties as dependent, to a great extent, on the nature of the elements other than hydrogen which it contained, or perhaps on the arrangement of all the elements in the particles of the acid. he regarded the hydrogen in an acid as capable of replacement by a metal, and to the metallic derivative--as it might be called--of the acid, thus produced, he gave the name of "salt." an acid might therefore be a compound of hydrogen with one other element--such were hydrochloric, hydriodic, hydrofluoric acids--or it might be a compound of hydrogen with two or more elements, of which one might or might not be oxygen--such were hydrocyanic acid and chloric or nitric acid. if the hydrogen in any of these acids were replaced by a metal a salt would be produced. a salt might therefore contain no oxygen, _e.g._ chloride or iodide of potassium; but in most cases salts did contain oxygen, _e.g._ chlorate or nitrate of potassium. acids were thus divided into oxyacids (or acids which contain oxygen) and acids containing no oxygen; the former class including most of the known acids. the old view of salts as being compounds of acids (_i.e._ oxides of the non-metallic elements) and bases (_i.e._ oxides of metals) was overthrown, and salts came to be regarded as metallic derivatives of acids. from this time, these terms--acids, salts, bases--become of less importance than they formerly were in the history of chemical advance. in trying to explain davy's electro-chemical theory i have applied the word _affinity_ to the mutual action and reaction between two substances which combine together to form a chemical compound. it is now necessary that we should look a little more closely into the history of this word _affinity_. oil and water do not mix together, but oil and potash solution do; the former may be said not to have, and the latter to have, an affinity one for the other. when sulphur is heated, the yellow odourless solid, seizing upon oxygen in the air, combines with it to produce a colourless strongly smelling gas. sulphur and oxygen are said to have strong affinity for each other. if equal weights of lime and magnesia be thrown into diluted nitric acid, after a time it is found that some of the lime, but very little of the magnesia, is dissolved. if an aqueous solution of lime be added to a solution of magnesia in nitric acid, the magnesia is precipitated in the form of an insoluble powder, while the lime remains dissolved in the acid. it is said that lime has a stronger affinity for nitric acid than magnesia has. such reactions as these used to be cited as examples of _single elective affinity_--single, because one substance combined with one other, and elective, because a substance seemed to choose between two others presented to it, and to combine with one to the exclusion of the other. but if a neutral solution of magnesia in sulphuric acid is added to a neutral solution of lime in nitric acid, sulphate of lime and nitrate of magnesia are produced. the lime, it was said, leaves the nitric and goes to the sulphuric acid, which, having been deserted by the magnesia, is ready to receive it; at the same time the nitric acid from which the lime has departed combines with the magnesia formerly held by the sulphuric acid. such a reaction was said to be an instance of _double affinities_. the chemical changes were caused, it was said, by the simultaneous affinity of lime for sulphuric acid, which was greater than its affinity for nitric acid, and the affinity of magnesia for nitric acid, which was greater than its affinity for sulphuric acid. if a number of salts were mixed, each base--supposing the foregoing statements to be correct--would form a compound with that acid for which it had the greatest affinity. it should then be possible to draw up tables of affinity. such tables were indeed prepared. here is an example:-- _sulphuric acid._ baryta. lime. strontia. ammonia. potash. magnesia. soda. this table tells us that the affinity of baryta for sulphuric acid is greater than that of strontia for the same acid, that of strontia greater than that of potash, and so on. it also tells that potash will decompose a compound of sulphuric acid and soda, just as soda will decompose a compound of the same acid with lime, or strontia will decompose a compound with potash, etc. but berthollet showed in the early years of this century that a large quantity of a body having a weak affinity for another will suffice to decompose a small quantity of a compound of this other with a third body for which it has a strong affinity. he showed, that is, that the formation or non-formation of a compound is dependent not only on the so-called affinities between the constituents, but also on the relative quantities of these constituents. berthollet and other chemists also showed that affinity is much conditioned by temperature; that is, that two substances which show no tendency towards chemical union at a low temperature may combine when the temperature is raised. he, and they, also proved that the formation or non-formation of a compound is much influenced by its physical properties. thus, if two substances are mixed in solution, and if by their mutual action a substance can be produced which is insoluble in the liquids present, that substance is generally produced whether the affinity between the original pair of substances be strong or weak. the outcome of berthollet's work was that tables of affinity became almost valueless. to say that the affinity of this body for that was greater than its affinity for a third body was going beyond the facts, because the formation of this or that compound depended on many conditions much more complex than those connoted by the term "affinity." yet the conception of affinity remained, although it could not be applied in so rigorous a way as had been done by the earlier chemists. if an element, a, readily combines with another element, b, under certain physical conditions, but does not, under the same conditions, combine with a third element, c, it may still be said that a and b have, and a and c have not, an affinity for each other. this general conception of affinity was applied by berzelius to the atoms of elements. affinity, said berzelius, acts between unlike atoms, and causes them to unite to form a compound atom, unlike either of the original atoms; cohesion, on the other hand, acts between like atoms, causing them to hold together without producing any change in their properties. affinity varies in different elements. thus the affinity of gold for oxygen is very small; hence it is that gold is found in the earth in the metallic state, while iron, having a great affinity for oxygen, soon rusts when exposed to air, or when buried in the earth. potassium and sodium have great affinities for oxygen, chlorine, etc.; yet the atoms of potassium and sodium do not themselves combine. the more any elements are alike chemically the smaller is their affinity for each other; the more any elements are chemically unlike the greater is their mutual affinity; but this affinity is modified by circumstances. thus, said berzelius, if equal numbers of atoms of a and b, having equal or nearly equal affinity for c, mutually react, compound atoms, ac and bc, will be produced, but atoms of a and b will remain. the amounts of ac and bc produced will be influenced by the greater or less affinity of a and b for c; but if there be a greater number of a than of b atoms, a greater amount of ac than of bc will be produced. in these cases all the reacting substances and the products of the actions are supposed to be liquids; but bc, if a solid substance, will be produced even if the affinity of a for c is greater than that of b for c. in some elements, berzelius taught, affinity slumbers, and can be awakened only by raising the temperature. thus carbon in the form of coal has no affinity for oxygen at ordinary temperatures; it has remained for ages in the earth without undergoing oxidation; but when coal is heated the affinities of carbon are awakened, combination with oxygen occurs, and heat is produced. but why is it that certain elementary atoms exhibit affinity for certain others? it depends, said berzelius, on the electrical states of these atoms. according to the berzelian theory, every elementary atom has attached to it a certain quantity of electricity, part of which is positive and part negative. this electricity is accumulated at two points on each atom, called respectively the positive pole and the negative pole; but in each atom one of these electricities so much preponderates over the other as to give the whole atom the character of either a positively or a negatively electrified body. when two atoms combine chemically the positive electricity in one neutralizes the negative electricity in the other. as we know that similar electricities repel, and opposite electricities attract each other, it follows that a markedly positive atom will exhibit strong affinity for a markedly negative atom, less strong affinity for a feebly negative, and little or no affinity for a positively electrified atom; but two similarly electrified atoms may exhibit affinity, because in every positive atom there is some negative electricity, as in every negative atom there is some positive electricity. thus, in the atoms of copper and zinc positive electricity predominates, said berzelius, but the zinc atoms are more positive than those of copper; hence, when the metals are brought into contact the negative electricity of the copper atoms is attracted and neutralized by the positive electricity of the zinc atoms, combination takes place, and the compound atom is still characterized by a predominance of positive electricity. hence berzelius identified "electrical polarity" with chemical affinity. every atom was regarded by him as _both_ positively _and_ negatively electrified; but as one of these electricities was always much stronger than the other, every atom regarded as a whole appeared to be _either_ positively _or_ negatively electrified. positive atoms showed affinity for negative atoms, and _vice versâ_. as a positive atom might become more positive by increasing the temperature of the atom, so might the affinity of this atom for that be more marked at high than at low temperatures. now, if two elementary atoms unite, the compound atom must--according to the berzelian views--be characterized either by positive or negative electricity. this compound atom, if positive, will exhibit affinity for other compound atoms in which negative electricity predominates; if negative, it will exhibit affinity for other positively electrified compound atoms. if two compound atoms unite chemically, the complex atom so produced will, again, be characterized by one or other of the two electricities, and as it is positive or negative, so will it exhibit affinity for positively or negatively electrified complex atoms. thus berzelius and his followers regarded every compound atom, however complex, as essentially built up of two parts, one of which was positively and the other negatively electrified, and which were held together chemically by virtue of the mutual attractions of these electricities; they regarded every compound atom as a _dual_ structure. the classification adopted by berzelius was essentially a dualistic classification. his system has always been known in chemistry as _dualism_. berzelius divided compound atoms (we should now say molecules) into three groups or orders-- _compound atoms of the first order_, formed by the immediate combination of atoms of two, or in organic compounds of three, elementary substances. _compound atoms of the second order_, formed by the combination of atoms of an element with atoms of the first order, or by the combination of two or more atoms of the first order. _compound atoms of the third order_, formed by combination of two or more atoms of the second order. when an atom of the third order was decomposed by an electric current, it split up, according to the berzelian teaching, into atoms of the second order--some positively, others negatively electrified. when an atom of the second order was submitted to electrolysis, it decomposed into atoms of the first order--some positively, others negatively electrified. berzelius said that a base is an electro-positive oxide, and an acid is an electro-negative oxide. the more markedly positive an oxide is, the more basic it is; the more negative it is, the more is it characterized by acid properties. one outcome of this teaching regarding acids and bases was to overthrow the lavoisierian conception of oxygen as the acidifying element. some oxides are positive, others negative, said berzelius; but acids are characterized by negative electricity, therefore the presence of oxygen in a compound does not always confer on that compound acid properties. we have already seen that silica was regarded by most chemists as a typical earth; but berzelius found that in the electrolysis of compounds of silica, this substance appeared at the positive pole of the battery--that is, the atom of silica belonged to the negatively electrified order of atoms. silica was almost certainly an oxide; but electro-negative oxides are, as a class, acids; therefore silica was probably an acid. the supposition of the acid character of silica was amply confirmed by the mineralogical analyses and experiments of berzelius. he showed that most of the earthy minerals are compounds of silica with electro-positive metallic oxides, and that silica plays the part of an acid in these minerals; and in he obtained the element silicon, the oxide of which is silica. on this basis berzelius reared a system of classification in mineralogy which much aided the advance of that branch of natural science. by the work of berzelius and davy the lavoisierian conception of acid has now been much modified and extended; it has been rendered less rigid, and is therefore more likely than before to be a guide to fresh discoveries. the older view of acid and alkali was based, for the most part, on a qualitative study of the reactions of chemical substances: bodies were placed in the same class because they were all sour, or all turned vegetable blues to red, etc. this was followed by a closer study of the composition of substances, and by attempts to connect the properties of these substances with their composition; but when this attempt resulted in the promulgation of the dictum that "oxygen is the acidifying principle," it began to be perceived that a larger basis of fact must be laid before just conclusions could be drawn as to the connections between properties and composition of substances. this larger basis was laid by the two chemists whose work we have now reviewed. of the life of one of these men i have already given such a sketch as i can from the materials available to me; of the life of the other we happily possess ample knowledge. let us now consider the main features of this life. * * * * * humphry davy, the eldest son of robert and grace davy, was born at penzance, in cornwall, on december , , eight months that is before the birth of berzelius. his parents resided on a small property which had belonged to their ancestors for several generations. surrounded by many kind friends by whom he was much thought of, the boy appears to have passed a very happy childhood. even at the age of five his quickness and penetration were marked by those around him, and at school these continued to be his predominant characteristics. nurtured from his infancy in the midst of beautiful and romantic scenery, and endowed with great observing power and a lively imagination, young davy seemed destined to be one of those from whose lips is "poured the deathless singing;" all through life he was characterized by a strongly marked poetic temperament. humphry davy was held in much esteem by his school friends as a composer of valentines and love letters, as a daring and entertaining teller of stories, and as a successful fireworks manufacturer. such a combination of qualities would much endear him to his boy-companions. we are told that at the age of eight he used to mount on an empty cart, around which a circle of boys would collect to be entertained by the wonderful tales of the youthful narrator. finishing his school education at the age of fifteen, he now began his own education of himself. in he was apprenticed to a surgeon and apothecary (afterwards a physician), in penzance, with whom he learned the elements of medical science; but his time during the years which he spent under mr. borlase was much occupied in shooting, fishing, searching for minerals and geological specimens, composing poetry, and pursuing metaphysical speculations. he was now, as through life, an enthusiastic lover of nature; his mind was extremely active, ranging over the most diverse subjects; he was full of imagination, and seemed certain to distinguish himself in any pursuit to which he should turn his attention. during the next three or four years davy indulged freely in speculations in all manner of subjects; he started, as people generally do when young, from general principles and followed these out to many conclusions. even in his study of physiology and other branches of science, he appears at this time to have adopted the speculative rather than the experimental method; but unlike most youthful metaphysicians he was ready to give up an opinion whenever it appeared to him incorrect. by the time he reached the age of twenty he had discarded this method of seeking for truth, and was ever afterwards distinguished by his careful working out of facts as the foundation for all his brilliant theories. davy appears to have begun the study of chemistry about by reading lavoisier's "elements of chemistry," the teachings of which he freely criticized. about this time mr. gregory watt came to live at penzance as a lodger with davy's mother, and with him the young philosopher had much talk on chemical and other scientific subjects. he also became acquainted with mr. davies gilbert--who was destined to succeed davy as president of the royal society--and from him he borrowed books and received assistance of various kinds in his studies. it was during these years that davy made experiments on heat, which were published some years later, and which are now regarded as laying the foundations of the modern theory according to which heat is due to the motions of the small parts of bodies. he arranged two brass plates so that one should carry a block of ice which might be caused to revolve in contact with the other plate; the plates were covered by a glass jar, from which he exhausted the air by means of a simple syringe of his own contrivance; the machine being placed on blocks of ice the plates were caused to revolve. the ice inside the jar soon melted; davy concluded that the heat required to melt this ice could only be produced by the friction of the ice and brass, and that therefore heat could not be any form of ponderable matter. in the year davy was asked to go to bristol as superintendent of the laboratory of a new pneumatic institution started by dr. beddoes for the application of gases to the treatment of diseases. davy had corresponded with beddoes before this time regarding his experiments on heat, and the latter seems to have been struck with his great abilities and to have been anxious to secure him as experimenter for his institution. davy was released from his engagements with mr. borlase, and, now about twenty years of age, set out for his new home, having made as he says all the experiments he could at penzance, and eagerly looking forward to the better appliances and incitements to research which he hoped to find at bristol. the pneumatic institution was supported by subscriptions, for the most part from scientific men. it was started on a scientific basis. researches were to be made on gases of various kinds with the view of applying these as remedies in the alleviation of disease. an hospital for patients, a laboratory for experimental research, and a lecture theatre were provided. at this time many men of literary and intellectual eminence resided in bristol; among these were coleridge and southey. most of these men were visitors at the house of dr. beddoes, and many distinguished men came from various parts of the county to visit the institution. davy thus entered on a sphere of labour eminently suited for the development of his genius. with ample mechanical appliances for research, with plenty of time at his disposal, surrounded by an atmosphere of inquiry and by men who would welcome any additions he could make to the knowledge of nature, and being at the same time not without poetic and imaginative surroundings, by which he was ever spurred onwards in the pursuit of truth--placed in these circumstances, such an enthusiastic and diligent student of science as davy could not but obtain results of value to his fellows. the state of chemical science at this time was evidently such as to incite the youthful worker. the chains with which stahl and his successors had so long bound the limbs of the young science had been broken by lavoisier; and although the french school of chemistry was at this time dominant, and not disinclined to treat as ignorant any persons who might differ from its teaching, yet there was plenty of life in the cultivators of chemistry. the controversy between berthollet and proust was about to begin; the lavoisierian views regarding acids and salts were not altogether accepted by gay-lussac, thenard and others; and from the laboratory of berzelius there was soon to issue the first of those numerous researches which drew the attention of every chemist to the capital of sweden. the voltaic battery had been discovered, and had opened up a region of possibilities in chemistry. davy began his researches at the institution by experiments with nitrous oxide, a gas supposed by some people at that time to be capable of producing most harmful effects on the animal system. he had to make many experiments before he found a method for preparing the pure gas, and in the course of these experiments he added much to the stock of chemical knowledge regarding the compounds of nitrogen and oxygen. having obtained fairly pure nitrous oxide, he breathed it from a silk bag; he experienced a "sensation analogous to gentle pressure on all the muscles;... the objects around me became dazzling and my hearing more acute;... at last an irresistible propensity to action was indulged in.... i recollect but indistinctly what followed; i know that my motions were various and violent." southey and coleridge breathed the gas; the poets only laughed a little. encouraged by the results of these experiments, davy proceeded to prepare and breathe nitric oxide--whereby he was rendered very ill--and then carburetted hydrogen--which nearly killed him. in his chemical note-book about this time, davy says, "the perfection of chemical philosophy, or the laws of corpuscular motion, must depend on the knowledge of all the simple substances, their mutual attractions, and the ratio in which the attractions increase or diminish with increase or diminution of temperature.... the first step towards these laws will be the decomposition of those bodies which are at present undecompounded." and in the same note-book he suggests methods which he thinks might effect the decomposition of muriatic and boric acids, the alkalis and earths. here are the germs of his future work. after about eight months' work at bristol he published a volume of "researches," which contained a great many new facts, and was characterized by vigour and novelty of conception. these researches had been carried out with intense application; each was struck off at a red heat. his mind during this time was filled with vast scientific conceptions, and he began also to think of fame. "an active mind, a deep ideal feeling of good, and a look towards future greatness," he tells us, sustained him. count rumford, the founder of the royal institution in london, was anxious to obtain a lecturer on chemistry for the institution. davy was strongly recommended, and after a little arrangement--concerning which davy says in a letter, "i will accept of no appointment except on the sacred terms of independence"--he was appointed assistant lecturer on chemistry and director of the laboratory. about a year later his official designation was changed to professor of chemistry. this appointment opened up a great sphere of research; "the sole and uncontrolled use of the apparatus of the institution for private experiments" was to be granted him, and he was promised "any apparatus he might need for new experiments." he had now the command of a good laboratory; he had not to undergo the drudgery of systematic teaching, but was only required to give lectures to a general audience. before leaving bristol he had commenced experiments on the chemical applications of the voltaic battery; these he at once followed up with the better apparatus now at his command. the results of this research, and his subsequent work on the alkalis and on muriatic acid and chlorine, have been already described. the circumstances of davy's life had hitherto been most favourable; how nobly he had availed himself of these circumstances was testified by the work done by him. his first lecture was delivered in the spring of , and at once he became famous. a friend of davy says, "the sensation created by his first course of lectures at the institution, and the enthusiastic admiration which they obtained, is scarcely to be imagined. men of the first rank and talent, the literary and the scientific, the practical and the theoretical, blue-stockings and women of fashion, the old and the young--all crowded, eagerly crowded the lecture-room. his youth, his simplicity, his natural eloquence, his chemical knowledge, his happy illustrations and well-conducted experiments, excited universal attention and unbounded applause. compliments, invitations and presents were showered upon him in abundance from all quarters; his society was courted by all, and all appeared proud of his acquaintance." one of his biographers says of these lectures, "he was always in earnest, and when he amused most, amusement appeared most foreign to his object. his great and first object was to instruct, and in conjunction with this, maintain the importance and dignity of science; indeed, the latter, and the kindling a taste for scientific pursuits, might rather be considered his main object, and the conveying instruction a secondary one." the greatest pains were taken by davy in the composition and rehearsal of his lectures, and in the arrangement of experiments, that everything should tend towards the enlightenment of his audience. surrounded by a brilliant society, invited to every fashionable entertainment, flattered by admirers, tempted by hopes of making money, davy remained a faithful and enthusiastic student of nature. "i am a lover of nature," he writes at this time to a friend, "with an ungratified imagination. i shall continue to search for untasted charms, for hidden beauties. my _real_, my _waking_ existence, is amongst the objects of scientific research. common amusements and enjoyments are necessary to me only as dreams to interrupt the flow of thoughts too nearly analogous to enlighten and vivify." during these years (_i.e._ from to ) he worked for the greater part of each day in the laboratory. every week, almost every day, saw some fresh discovery of importance. he advanced from discovery to discovery. his work was characterized by that vast industry and extreme rapidity which belong only to the efforts of genius. never, before or since, has chemical science made such strides in this country. in davy was elected a fellow, and in one of the secretaries of the royal society. in he retired from the professorship of chemistry at the royal institution; in the same year he was made a knight. the next two or three years were mostly spent in travelling abroad with his wife--he had married a widow lady, mrs. apreece, in . during his visit to paris he made several experiments on the then recently discovered iodine, and proved this substance to be an element. the work which davy had accomplished in the seventeen years that had now elapsed since he began the study of chemistry, whether we consider it simply as a contribution to chemical science, or in the light of the influence it exerted on the researches of others, was of first-rate importance; but a fresh field now began to open before him, from which he was destined to reap the richest fruits. in the autumn of his attention was drawn to the subject of fire-damp in coal-mines. as he passed through newcastle, on his return from a holiday spent in the scottish highlands, he examined various coal-mines and collected samples of fire-damp; in december of the same year his _safety-lamp_ was perfected, and soon after this it was in the hands of the miner. the steps in the discovery of this valuable instrument were briefly these. davy established the fact that fire-damp is a compound of carbon and hydrogen; he found that this gas must be mixed with a large quantity of ordinary air before the mixture becomes explosive, that the temperature at which this explosion occurs is a high one, and that but little heat is produced during the explosion; he found that the explosive mixture could not be fired in narrow metallic tubes, and also that it was rendered non-explosive by addition of carbonic acid or nitrogen. he reasoned on these facts thus: "it occurred to me, as a _considerable_ heat was required for the inflammation of the fire-damp, and as it produced in burning a comparatively _small degree_ of heat, that the effect of carbonic acid and azote, and of the surfaces of small tubes, in preventing its explosion, depended on their cooling powers--upon their lowering the temperature of the exploding mixture so much that it was no longer sufficient for its continuous inflammation." he at once set about constructing a lamp in which it should be impossible for the temperature of ignition of a mixture of fire-damp and air to be attained, and which therefore, while burning, might be filled with this mixture without any danger of an explosion. he surrounded the flame of an oil-lamp with a cylinder of fine wire-gauze; this lamp when brought into an atmosphere containing fire-damp and air could not cause an explosion, because although small explosions might occur in the interior of the wire cylinder, so much heat was conducted away by the large metallic surface that the temperature of the explosive atmosphere outside the lamp could not attain that point at which explosion would occur. in sir humphry davy was made a baronet, in recognition of his great services as the inventor of the safety-lamp; and in he was elected to the most honourable position which can be held by a man of science in this country, he became the president of the royal society. for seven years he was annually re-elected president, and during that time he was the central figure in the scientific society of england. during these years he continued his investigations chiefly on electro-chemical subjects and on various branches of applied science. in his health began to fail. an attack of paralysis in that year obliged him to relinquish most of his work. he went abroad and travelled in italy and the tyrol, sometimes strong enough to shoot or fish a little, or even to carry on electrical experiments; sometimes confined to his room, or to gentle exercise only. he resigned the presidentship of the royal society in . in he visited rome, where he was again attacked by paralysis, and thought himself dying, but he recovered sufficiently to attempt the journey homeward. at geneva he became very ill, and expired in that city on the th of may . during these later years of illness and suffering, his intense love of and delight in nature were very apparent; he returned again to the simple tastes and pleasures of his early days. his intimate knowledge of natural appearances and of the sights and sounds of country life is conspicuous in the "salmonia, or days of fly-fishing," written during his later years. sir humphry davy was emphatically a genius. he was full of eager desire to know the secrets of the world in which he lived; he looked around him with wonder and delight, ever conscious of the vastness of the appearances which met his gaze; an exuberance of life and energy marked his actions; difficulties were encountered by him only to be overcome; he was depressed by no misfortunes, deterred by no obstacles, led aside from his object by no temptations, and held in bondage by no false analogies. his work must ever remain as a model to the student of science. a thorough and careful foundation of fact is laid; on this, hypotheses are raised, to be tested first by reasoning and argument, then by the tests of the laboratory, which alone are final. analogies are seized; hints are eagerly taken up, examined, and acted on or dismissed. as he works in the laboratory, we see his mind ranging over the whole field of chemical knowledge, finding a solution of a difficulty here, or guessing at a solution there; combining apparently most diverse facts; examining phenomena which appear to have no connection; never dwelling too long on an hypothesis which cannot yield some clue to the object of research, but quickly discovering the road which will lead to the wished-for solution. like so many great experimenters davy accomplished wonders with little apparatus. when he went abroad for the first time he took with him two small boxes, one twenty, and the other twelve inches long, by about seven inches wide and four deep. with the apparatus contained in these boxes he established the elementary nature of iodine, and made a rough estimation of its atomic weight; he determined many of its analogies with chlorine, proving that, like chlorine, it is markedly electro-negative, and that its compounds are decomposed by chlorine; he accomplished the synthesis of hydriodic acid, and approximately determined the composition of iodide of nitrogen. but when it was necessary to employ delicate or powerful apparatus, he was able by the use of that also to obtain results of primary importance. the decomposition of potash, soda, baryta, lime and strontia could not have been effected had he not had at his command the resources of a well-furnished laboratory. davy has had no successor in england. much useful and some brilliant work has been done by english chemists since his day, but we still look back to the first quarter of the century as the golden age of chemistry in this country. on the roll wherein are written the names of england's greatest sons, there is inscribed but a single chemist--humphry davy. * * * * * i carried on the account of the work of davy's great contemporary, berzelius, to the time when he had fairly established dualistic views of the structure of chemical compounds, and when, by the application of a few simple rules regarding the combinations of elementary atoms, he had largely extended the bounds of the atomic theory of dalton. berzelius also did important work in the domain of organic chemistry. by numerous analyses of compounds of animal and vegetable origin, he clearly established the fact that the same laws of combination, the same fixity of composition, and the same general features of atomic structure prevail among the so-called organic as among the inorganic compounds. in doing this he broke down the artificial barrier which had been raised between the two branches of the science, and so prepared the way for modern chemistry, which has won its chief triumphs in the examination of organic compounds. by the many and great improvements which he introduced into analytical chemistry, and by the publication of his "textbook of chemistry," which went through several editions in french and german, and also of his yearly report on the advance of chemistry, berzelius exerted a great influence on the progress of his favourite science. wöhler tells us that when the spring of the year came, at which time his annual report had to be prepared, berzelius shut himself up in his study, surrounded himself with books, and did not stir from the writing-table until the work was done. in his later days berzelius was much engaged in controversy with the leaders of the new school, the rise and progress of which will be traced in the next chapter, but throughout this controversy he found time to add many fresh facts to those already known. he continued his researches until his death in . the work of the great swedish chemist is characterized by thoroughness in all its parts: to him every fact appeared to be of importance; although now perhaps only an isolated fact, he saw that some day it would find a place in a general scheme of classification. he worked in great measure on the lines laid down by dalton and davy; the enormous number and accuracy of his analyses established the law of multiple proportions on a sure basis, and his attempts to determine the constitution of compound atoms, while advancing the atomic theory of dalton, drew attention to the all-important distinction between atom and molecule, and so prepared chemists for the acceptance of the generalization of avogadro. the electro-chemical conceptions of davy were modified by berzelius; they were shorn of something of their elasticity, but were rendered more suited to be the basis of a rigid theory. * * * * * at the close of this transition period from the lavoisierian to the modern chemistry, we find analytical chemistry established as an art; we find the atomic theory generally accepted, but we notice the existence of much confusion which has arisen from the non-acceptance of the distinction made by avogadro between atom and molecule; we find the analogies between chemical affinity and electrical energy made the basis of a system of classification which regards every compound atom (or molecule) as built up of two parts, in one of which positive, and in the other negative electricity predominates; and accompanying this system of classification we find that an acid is no longer regarded as necessarily an oxygen compound, but rather as a compound possessed of certain properties which are probably due to the arrangement of the elementary atoms, among which hydrogen appears generally to find a place; we find that salts are for the most part regarded as metallic derivatives of acids; and we find that by the decomposition of the supposed elementary substances, potash, soda, lime, etc., the number of the elements has been extended, the application of a new instrument of research has been brilliantly rewarded, and the lavoisierian description of "element" as the "attained, not the attainable, limit of research" has been emphasized. footnotes: [ ] the history and meaning of these terms is considered on p. , _et seq._ [ ] for an explanation of this expression, "chemical affinity," see p. , _et seq._ [ ] these views have been already explained on pp. , . chapter v. the work of graham. _thomas graham_, - . the work of graham, concerned as it mostly was with the development of the conception of atoms, connects the time of dalton with that in which we are now living. i have therefore judged it advisable to devote a short chapter to a consideration of the life-work of this chemist, before proceeding to the third period of chemical advance, that, namely, which witnessed the development of organic chemistry through the labours of men who were graham's contemporaries. the printed materials which exist for framing the story of graham's life are very meagre, but as he appears, from the accounts of his friends, to have devoted himself entirely to scientific researches, we cannot go far wrong in regarding the history of his various discoveries as also the history of his life. * * * * * thomas graham was born in glasgow, on december , . his father, james graham, a successful manufacturer, was in a position to give his son a good education. after some years spent in the ordinary school training, graham entered glasgow university at the early age of fourteen, and graduated as m. a. five years later. it was the intention of graham's father that his son should enter the scottish church; but under the teaching of dr. thomas thomson and others the lad imbibed so strong a love of natural science, that rather than relinquish the pursuit of his favourite study, he determined to be independent of his father and make a living for himself. his father was much annoyed at the determination of his son to pursue science, and vainly attempted to force him into the clerical profession. the quarrel between father and son increased in bitterness, and notwithstanding the intervention of friends the father refused to make his son any allowance for his maintenance; and although many years after a reconcilement was effected, yet at the time when graham most needed his father's help he was left to struggle alone. graham went to edinburgh, where he pursued his studies under hope and leslie, professors of chemistry and physics respectively--men whose names were famous wherever natural science was studied. graham's mother, for whom he had always the greatest respect and warmest love, and his sister margaret helped him as best they could during this trying time. the young student found some literary occupation and a little teaching in edinburgh, and sometimes he was asked to make investigations in subjects connected with applied chemistry. thus he struggled on for four or five years, during which time he began to publish papers on chemico-physical subjects. in the year he was appointed lecturer on chemistry at the mechanics' institution in glasgow, and next year he was removed to the more important position of lecturer on the same science at the andersonian institution in that city. this position he occupied for seven years, when he was elected professor of chemistry in the university of london (now university college): he had been elected to the fellowship of the royal society in the preceding year. during his stay at the andersonian institution graham had established his fame as a physical chemist; he had begun his work on acids and salts, and had established the fundamental facts concerning gaseous diffusion. these researches he continued in london, and from to he enriched chemical science with a series of papers concerned for the most part with attempts to trace the movements of the atoms of matter. in graham succeeded sir john herschel in the important and honourable position of master of the mint. for some years after his appointment he was much engaged with the duties of his office, but about he again returned to his atomic studies, and in his papers on "transpiration of liquids" and on "dialysis" he did much in the application of physical methods to solve chemical problems, and opened up new paths, by travelling on which his successors greatly advanced the limits of the science of chemistry. graham was almost always at work; his holidays were "few and far between." by the year or so his general health began to grow feeble; in the autumn of , during a visit to malvern where he sought repose and invigorating air, he caught cold, which developed into inflammation of the lungs. on his return to london the disease was overcome by medical remedies, but he continued very weak, and gradually sank, till the end came on the th of september . i have said that the seven years during which graham held the lectureship on chemistry in the andersonian institution, glasgow, witnessed the beginning alike of his work on salts and of that on gaseous diffusion. he showed that there exists a series of compounds of various salts, _e.g._ chloride of calcium, chloride of zinc, etc., with alcohol. he compared the alcohol in these salts, which he called _alcoates_, to the water in ordinary crystallized salts, and thus drew the attention of chemists to the important part played by water in determining the properties of many substances. three years later ( ) appeared one of his most important papers, bearing on the general conception of acids: "researches on the arseniates, phosphates, and modifications of phosphoric acid." chemists at this time knew that phosphoric acid--that is, the substance obtained by adding water to pentoxide of phosphorus--exhibited many peculiarities, but they were for the most part content to leave these unexplained. graham, following up the analogy which he had already established between water and bases, prepared and carefully determined the composition of a series of phosphates, and concluded that pentoxide of phosphorus is able to combine with a base--say soda--in three different proportions, and thus to produce three different phosphates of soda. but as graham accepted that view which regards a salt as a metallic derivative of an acid, he supposed that three different phosphoric acids ought to exist; these acids he found in the substances produced by the action of water on the oxide of phosphorus. he showed that just as the oxide combines with a base in three proportions, so does it combine with water in three proportions. this water he regarded as chemically analogous to the base in the three salts, one atom (we should now rather say molecule) of base could be replaced by one atom of water, two atoms of base by two atoms of water, or three atoms of base by three atoms of water. phosphoric acid was therefore regarded by graham as a compound of pentoxide of phosphorus and water, the latter being as essentially a part of the acid as the former. he distinguished between _monobasic_, _dibasic_, and _tribasic_ phosphoric acids: by the action of a base on the _monobasic acid_, one, and only one salt was produced; the _dibasic acid_ could furnish two salts, containing different proportions (or a different number of atoms) of the same base: and from the _tribasic acid_ three salts, containing the same base but in different proportions, could be obtained. davy's view of an acid as a compound of water with a negative oxide was thus confirmed, and there was added to chemical science the conception of _acids of different basicity_. in graham's paper on "water as a constituent of salts" was published in the "transactions of the royal society of edinburgh." in this paper he inquires whether the water in crystalline salts can or cannot be removed without destroying the chemical individuality of the salts. he finds that in some crystalline salts part of the water can be easily removed by the application of heat, but the remainder only at very high temperatures. he distinguishes between those atoms of water which essentially belong to the compound atom of the salt, and those atoms which can be readily removed therefrom, which are as it were added on to, or built up around the exterior of the atom of salt. in this paper graham began to distinguish what is now called _water of crystallization_ from _water of constitution_, a distinction pointed to by some of davy's researches, but a distinction which has remained too much a mere matter of nomenclature since the days of graham. in these researches graham emphasized the necessity of the presence of hydrogen in all true acids; as he had drawn an analogy between water and bases, so now he saw in the hydrogen of acids the analogue of the metal of salts. he regarded the structure of the compound atom of an acid as similar to that of the compound atom of a salt; the hydrogen atom, or atoms, in the acid was replaced by a metallic atom, or atoms, and so a compound atom of the salt was produced. davy and berzelius had proved that hydrogen is markedly electro-positive; hydrogen appeared to graham to belong to the class of metals. in making this bold hypothesis graham necessarily paid little heed to those properties of metals which appeal to the senses of the observer. metals, as a class, are lustrous, heavy, malleable substances; hydrogen is a colourless, inodourless, invisible, very light gas: how then can hydrogen be said to be metallic? i have again and again insisted on the need of imagination for the successful study of natural science. although in science we deal with phenomena which we wish to measure and weigh and record in definite and precise language, yet he only is the successful student of science who can penetrate beneath the surface of things, who can form mental pictures different from those which appear before his bodily eye, and so can discern the intricate and apparently irregular analogies which explain the phenomena he is set to study. graham was not as far as we can learn endowed, like davy, with the sensitive nature of a poet, yet his work on hydrogen proves him to have possessed a large share of the gift of imagination. picturing to himself the hydrogen atom as essentially similar in its chemical functions to the atom of a metal, he tracked this light invisible gas through many tortuous courses: he showed how it is absorbed and retained (_occluded_ as he said) by many metals; he found it in meteors which had come from far-away regions of space; and at last, the year before he died he prepared an alloy of palladium and the metal hydrogen, from which a few medals were struck, bearing the legend "palladium-hydrogenium ." within the last few years hydrogen has been liquified and, it is said, solidified. solid hydrogen is described as a steel-grey substance which fell upon the table with a sound like the ring of a metal. but graham's most important work was concerned with the motion of the ultimate particles of bodies. he uses the word "atom" pretty much as dalton did. he does not make a distinction between the atom of an element and the atom of a compound, but apparently uses the term as a convenient one to express the smallest undivided particle of any chemical substance which exhibits the properties of that substance. as graham was chiefly concerned with the physical properties of chemical substances, or with those properties which are studied alike by chemistry and physics, the distinction between atom and molecule, so all-important in pure chemistry, might be, and to a great extent was, overlooked by him. in considering his work we shall however do well to use the terms "atom" and "molecule" in the sense in which they are now always used in chemistry, a sense which has been already discussed (see pp. - ). many years before graham began his work a curious fact had been recorded but not explained. in döbereiner filled a glass jar with hydrogen and allowed the jar to stand over water: on returning after twelve hours he found that the water had risen about an inch and a half into the jar. close examination of the jar showed the presence of a small crack in the glass. many jars, tubes and flasks, all with small cracks in the glass, were filled with hydrogen and allowed to stand over water; in every case the water rose in the vessel. no rise of the water was however noticeable if the vessels were filled with ordinary air, nitrogen or oxygen. in graham began the investigation of the peculiar phenomenon observed by döbereiner. repeating döbereiner's experiments, graham found that a portion of the hydrogen in the cracked vessels passed outwards through the small fissures, and a little air passed inwards: the water therefore rose in the jar, tube or flask, because there was a greater pressure on the surface of the water outside than upon that inside the vessel. any gas lighter than air behaved like hydrogen; when gases heavier than air were employed the level of the water inside the vessel was slightly lowered after some hours. graham found that the passage of gases through minute openings could be much more accurately studied by placing the gas to be examined in a glass tube one end of which was closed by a plug of dry plaster of paris, than by using vessels with small fissures in the glass. the _diffusion-tube_ used by graham generally consisted of a piece of glass tubing, graduated in fractions of a cubic inch and having a bulb blown near one end; the short end was closed by a thin plug of dry plaster of paris (gypsum), the tube was filled with the gas to be examined, and the open end was immediately immersed in water. the water was allowed to rise until it had attained a constant level, when it was found that the whole of the gas originally in the tube had passed outwards through the porous plug, and air had passed inwards. the volume of gas originally in the tube being known, and the volume of air in the tube at the close of the experiment being measured, it was only necessary to divide the former by the latter number in order to obtain the number of volumes of gas which had passed outwards for each one volume of air which had passed inwards; in other words to obtain the _rate of diffusion_ compared with air of the gas under examination. graham's results were gathered together in the statement, "the diffusion-rates of any two gases are inversely as the square roots of their densities." thus, take oxygen and hydrogen: oxygen is sixteen times heavier than hydrogen, therefore hydrogen diffuses four times more rapidly than oxygen. take hydrogen and air: the specific gravity of hydrogen is · , air being ; the square root of · is · , therefore hydrogen will diffuse more rapidly than air in the ratio of · : . in the years - graham resumed this inquiry; he now distinguished between _diffusion_, or the passage of gases through porous plates, and _transpiration_, or the passage of gases through capillary tubes. he showed that if a sufficiently large capillary tube be employed the rate of transpiration of a gas becomes constant, but that it is altogether different from the rate of diffusion of the same gas. he established the fact that there is a connection of some kind between the transpiration-rates and the chemical composition of gases, and in doing this he opened up a field of inquiry by cultivating which many important results have been gained within the last few years, and which is surely destined to yield more valuable fruit in the future. returning to the diffusion of gases, graham, after nearly thirty years' more or less constant labour, begins to speculate a little on the causes of the phenomena he had so studiously and perseveringly been examining. in his paper on "the molecular mobility of gases," read to the royal society in , after describing a new diffusion-tube wherein thin plates of artificial graphite were used in place of plaster of paris, graham says, "the pores of artificial graphite appear to be really so minute that a gas _in mass_ cannot penetrate the plate at all. it seems that molecules only can pass; and they may be supposed to pass wholly unimpeded by friction, for the smallest pores that can be imagined to exist in the graphite must be tunnels in magnitude to the ultimate atom of a gaseous body." he then shortly describes the molecular theory of matter, and shows how this theory--a sketch of which so far as it concerns us in this book has been given on pp. - --explains the results which he has obtained. when a gas passed through a porous plate into a vacuum, or when one gas passed in one direction and another in the opposite direction through the same plate, graham saw the molecules of each gas rushing through the "tunnels" of graphite or stucco. the average rate at which the molecules of a gas rushed along was the diffusion-rate of that gas. the lighter the gas the more rapid was the motion of its molecules. if a mixture of two gases, one much lighter than the other, were allowed to flow through a porous plate, the lighter gas would pass so much more quickly than the heavier gas that a partial separation of the two might probably be effected. graham accomplished such a separation of oxygen and hydrogen, and of oxygen and nitrogen; and he described a simple instrument whereby this process of _atmolysis_, as he called it, might be effected. graham's _tube atmolyser_ consisted of a long tobacco-pipe stem placed inside a rather shorter and considerably wider tube of glass; the pipe stem was fixed by passing through two corks, one at each end of the glass tube; through one of these corks there also passed a short piece of glass tubing. when the instrument was employed, the piece of short glass tubing was connected with an air-pump, and one end of the pipe stem with the gaseous mixture--say ordinary air. the air-pump being set in motion, the gaseous mixture was allowed to flow slowly through the pipe stem; the lighter ingredient of the mixture passed outwards through the pipe stem into the wide glass tube more rapidly than the heavier ingredient, and was swept away to the air-pump; the heavier ingredient could be collected, mixed with only a small quantity of the lighter, at the other end of the pipe stem. as graham most graphically expressed it, "the stream of gas diminishes as it proceeds, like a river flowing over a pervious bed." graham then contrived a very simple experiment whereby he was able to measure the rate of motion of the molecules of carbonic acid. he introduced a little carbonic acid into the lower part of a tall cylindrical jar, and at the close of certain fixed periods of time he determined the amount of carbonic acid which had diffused upwards through the air into the uppermost layer of the jar. knowing the height of the jar, he now knew the distance through which a small portion of carbonic acid passed in a stated time, and regarding this small portion as consisting of a great many molecules, all moving at about equal rates, he had determined the average velocity of the molecules of carbonic acid. a similar experiment was performed with hydrogen. the general results were that the molecules of carbonic acid move about in still air with a velocity equal to seventy-three millimetres per minute, and that under the same conditions the molecules of hydrogen move with a velocity equal to about one-third of a metre per minute.[ ] the bakerian lecture for , read by graham before the royal society, was entitled "on the diffusion of liquids." in this paper he describes a very large number of experiments made with a view to determine the rate at which a salt in aqueous solution diffuses, or passes upwards into a layer of pure water above it, the salt solution and the water not being separated by any intervening medium. graham's method of procedure consisted in completely filling a small bottle with a salt solution of known strength, placing this bottle in a larger graduated vessel, and carefully filling the latter with water. measured portions of the water in the larger vessel were withdrawn at stated intervals, and the quantity of salt in each portion was determined. graham found that under these conditions salts diffused with very varying velocities. groups of salts showed equal rates of diffusion. there appeared to be no definite connection between the molecular weights of the salts and their diffusion-rates; but as graham constantly regarded diffusion, whether of gases or liquids, as essentially due to the movements of minute particles, he thought that the particles which moved about as wholes during diffusion probably consisted of groups of what might be called chemical molecules--in other words, graham recognized various orders of small particles. as the atom was supposed to have a simpler structure than the molecule (if indeed it had a structure at all), so there probably existed groups of molecules which, under certain conditions, behaved as individual particles with definite properties. as graham applied the diffusion of gases to the separation of two gases of unequal densities, so he applied the diffusion of liquids to the separation of various salts in solution. he showed also that some complex salts, such as the alums, were partially separated into their constituents during the process of diffusion. the prosecution of these researches led to most important results, which were gathered together in a paper on "liquid diffusion applied to analysis," read to the royal society in . graham divided substances into those which diffused easily and quickly into water, and those which diffused very slowly; he showed that the former were all crystallizable substances, while the latter were non-crystallizable jelly-like bodies. graham called these jelly-like substances _colloids;_ the easily diffusible substances he called _crystalloids_. he proved that a colloidal substance acts towards a crystalloid much as water does; that the crystalloid rapidly diffuses through the colloid, but that colloids are not themselves capable of diffusing through other colloids. on this fact was founded graham's process of _dialysis_. as colloid he employed a sheet of parchment paper, which he stretched on a ring of wood or caoutchouc, and floated the apparatus so constructed--_the dialyser_--on the surface of pure water in a glass dish; he then poured into the dialyser the mixture of substances which it was desired to separate. let us suppose that this mixture contained sugar and gum; the crystalloidal sugar soon passed through the parchment paper, and was found in the water outside, but the colloidal gum remained in the dialyser. if the mixture in the dialyser contained two crystalloids, the greater part of the more diffusible of these passed through the parchment in a short time along with only a little of the less diffusible; a partial separation was thus effected. this method of dialysis was applied by graham to separate and obtain in the pure state many colloidal modifications of chemical compounds, such as aluminium and tin hydrates, etc. by his study of these peculiar substances graham introduced into chemistry a new class of bodies, and opened up great fields of research. matter in the colloidal state appears to be endowed with properties which are quite absent, or are hidden, when it is in the ordinary crystalloidal condition. colloids are readily affected by the smallest changes in external conditions; they are eminently unstable bodies; they are, graham said, always on the verge of an impending change, and minute disturbances in the surrounding conditions may precipitate this change at any moment. crystalloids, on the other hand, are stable; they have definite properties, which are not changed without simultaneous large changes in surrounding conditions. but although, to use graham's words, these classes of bodies "appear like different worlds of matter," there is yet no marked separating line between them. ice is a substance which under ordinary conditions exhibits all the properties of crystalloids, but ice formed in contact with water just at the freezing point is not unlike a mass of partly dried gum; it shows no crystalline structure, but it may be rent and split like a lump of glue, and, like glue, the broken pieces may be pressed together again and caused to adhere into one mass. "can any facts," asks graham, "more strikingly illustrate the maxim that in nature there are no abrupt transitions, and that distinctions of class are never absolute?" in the properties of colloids and crystalloids graham saw an index of diversity of molecular structure. the smallest individual particle of a colloid appeared to him to be a much more complex structure than the smallest particle of a crystalloid. the colloidal molecule appeared to be formed by the gathering together of several crystalloidal molecules; such a complex structure might be expected readily to undergo change, whereas the simpler molecule of a crystalloid would probably present more definite and less readily altered properties. in this research graham had again, as so often before, arrived at the conception of various orders of small particles. in the early days of the daltonian theory it seemed that the recognition of atoms as ultimate particles, by the placing together of which masses of this or that kind of matter are produced, would suffice to explain all the facts of chemical combinations; but dalton's application of the term "atom" to elements and compounds alike implied that an atom might itself have parts, and that one atom might be more complex than another. the way was thus already prepared for the recognition of more than one order of atoms, a recognition which was formulated three years after the appearance of dalton's "new system" in the statement of avogadro, "equal volumes of gases contain equal numbers of molecules;" for we have seen that the application of this statement to actually occurring reactions between gases obliges us to admit that the molecules of hydrogen, oxygen and many other elementary gases are composed of two distinct parts or atoms. berzelius it is true did not formally accept the generalization of avogadro; but we have seen how the conception of atom which runs through his work is not that of an indivisible particle, but rather that of a little individual part of matter with definite properties, from which the mass of matter recognizable by our senses is constructed, just as the wall is built up of individual bricks. and as the bricks are themselves constructed of clay, which in turn is composed of silica and alumina, so may each of these little parts of matter be constructed of smaller parts; only as clay is not brick, and neither silica nor alumina is clay, so the properties of the parts of the atom--if it has parts--are not the properties of the atom, and a mass of matter constructed of these parts would not have the same properties as a mass of matter constructed of the atoms themselves. another feature of graham's work is found in the prominence which he gives to that view of a chemical compound which regards it as the resultant of the action and reaction of the parts of the compound. as the apparent stability of chemical compounds was seen by davy to be the result of an equilibrium of contending forces, so did the seemingly changeless character of any chemical substance appear to graham as due to the orderly changes which are continually proceeding among the molecules of which the substance is constructed. a piece of lime, or a drop of water, was to the mind of graham the scene of a continual strife, for that minute portion of matter appeared to him to be constructed of almost innumerable myriads of little parts, each in more or less rapid motion, one now striking against another and now moving free for a little space. interfere with those movements, alter the mutual action of those minute particles, and the whole building would fall to pieces. for more than thirty years graham was content to trace the movements of molecules. during that time he devoted himself, with an intense and single-minded devotion, to the study of molecular science. undaunted in early youth by the withdrawal of his father's support; unseduced in his middle age by the temptations of technical chemistry, by yielding to which he would soon have secured a fortune; undazzled in his later days by the honours of the position to which he had attained; graham dedicated his life to the nobler object of advancing the bounds of natural knowledge, and so adding to those truths which must ever remain for the good and furtherance of humanity. footnotes: [ ] a metre is equal to about thirty-nine inches; a millimetre is the one-thousandth part of a metre. chapter vi. rise and progress of organic chemistry--period of liebig and dumas. _justus liebig, - . jean baptiste andré dumas, born in ._ i have as yet said almost nothing with regard to the progress of organic chemistry, considered as a special branch of the science. it is however in this department that the greatest triumphs which mark the third period of chemical advance have been won. we must therefore now turn our attention to the work which has been done here. the ancients drew no such distinction between portions of their chemical knowledge, limited as it was, as is implied by the modern terms "organic" and "inorganic chemistry." an organic acid--acetic--was one of the earliest known substances belonging to the class of acids; many processes of chemical handicraft practised in the olden times dealt with the manufacture of substances, such as soap, leather or gum, which we should now call organic substances. nor did the early alchemists, although working chiefly with mineral or inorganic substances, draw any strict division between the two branches of chemistry. the medical chemists of the sixteenth century dealt much with substances derived from plants and animals, such as benzoic and succinic acids, spirit of wine, oils, etc. but neither in their nomenclature nor in their practice did they sharply distinguish inorganic from organic compounds. they spoke of the _quintessence_ of arsenic and the _quintessence_ of alcohol; they applied the term "oil" alike to the products of the action of acids on metallic salts and to substances obtained from vegetables. but towards the end of the seventeenth century, at the time that is when the phlogistic theory began to gain pre-eminence, we find gradually springing up a division of chemical substances into mineral, animal and vegetable substances--a division which was based rather on a consideration of the sources whence the substances were derived than on the properties of the substances themselves, and therefore a division which was essentially a non-chemical one. about a century after this, systematic attempts began to be made to trace some peculiarity of composition as belonging to all compounds of organic, that is, of animal or vegetable, origin. as very many of the substances then known belonging to this class were more or less oil-like in their properties--oils, fats, balsams, gums, sugar, etc.--organic substances generally were said to be characterized by the presence in them of the _principle of oil_. such a statement as this, although suited to the conceptions of that time, could not be received when lavoisier had shown chemists how nature ought be examined. with the definite conception of element introduced by the new chemistry, came an attempt to prove that organic compounds were built up of elements which were rarely found together in any one compound of inorganic origin. substances of vegetable origin were said by lavoisier to be composed of carbon, hydrogen and oxygen, while phosphorus and nitrogen, in addition to those three elements, entered into the composition of substances derived from animals. but neither could this definition of organic compounds be upheld in the face of facts. wax and many oils contained only carbon and hydrogen, yet they were undoubtedly substances of vegetable or animal origin. if the presence of any two of the three elements, carbon, hydrogen and oxygen, were to be regarded as a sufficient criterion for the classification of a compound, then it was necessary that carbonic acid--obtained by the action of a mineral acid on chalk--should be called an organic compound. to berzelius belongs the honour of being the chemist who first applied the general laws of chemical combination to all compounds alike, whether derived from minerals, animals, or vegetables. the ultimate particles, or molecules, of every compound were regarded by berzelius as built up of two parts, each of which might itself be an elementary atom, or a group of elementary atoms. one of these parts, he said, was characterized by positive, the other by negative electricity. every compound molecule, whatever was the nature or number of the elementary atoms composing it, was a dual structure (see p. ). organic chemistry came again to be a term somewhat loosely applied to the compounds derived from animals or vegetables, or in the formation of which the agency of living things was necessary. most, if not all of these compounds contained carbon and some other element or elements, especially hydrogen, oxygen and nitrogen. but the progress of this branch of chemistry was impeded by the want of any trustworthy methods for analysing compounds containing carbon, oxygen and hydrogen. this want was to be supplied, and the science of organic chemistry, and so of chemistry in general, was to be immensely advanced by the labours of a new school of chemists, chief among whom were liebig and dumas. let us shortly trace the work of these two renowned naturalists. the life-work of the first is finished; i write this story of the progress of his favourite science on the eighty-second birthday of the second of these great men, who is still with us a veteran crowned with glory, a true soldier in the battle against ignorance and so against want and crime. * * * * * justus liebig was born at darmstadt, on the th of may . the main facts which mark his life regarded apart from his work as a chemist are soon told. showing a taste for making experiments he was apprenticed by his father to an apothecary. fortunately for science he did not long remain as a concoctor of drugs, but was allowed to enter the university of bonn as a student of medicine. from bonn he went to erlangen, at which university he graduated in . a year or two before this time liebig had begun his career as an investigator of nature, and he had already made such progress that the grand duke of hesse-darmstadt was prevailed on to grant him a small pension and allow him to prosecute his researches at paris, which was then almost the only place where he could hope to find the conditions of success for the study of scientific chemistry. to paris accordingly he went in . he was so fortunate--thanks to the good graces of the renowned naturalist alexander von humboldt--as to be allowed to enter the laboratory of gay-lussac, where he continued the research on a class of explosive compounds, called _fulminates_, which he had begun before leaving darmstadt. a year later liebig was invited to return to his native country as professor of chemistry in the small university of giessen--a name soon to be known wherever chemistry was studied, and now held dear by many eminent chemists who there learned what is meant by the scientific study of nature. the year before liebig entered the laboratory of gay-lussac there came to paris a young and enthusiastic student who had already made himself known in the scientific world by his physiological researches, and who was now about to begin his career as a chemist. in that southern part of france which is rich in memories of the roman occupation, not far from the remains of the great aqueduct which spans the valley of the gardon, at no great distance from the famous cities of arles and nîmes, was born, in the town of alais, on the th of july , jean baptiste andrÉ dumas. the father of dumas was a man of considerable culture; he gave his son as good an education as could be obtained in the little town of his birth. at the age of fourteen young dumas was a good classical scholar, and had acquired a fair knowledge of natural science. but for his deficiency in mathematics he would probably have entered for the examination which admitted those who passed it to join the french navy. but before he had made good his mathematical deficiencies the troublous nature of the times ( - ) obliged his parents to think of some other profession for their son which would entail less sacrifice on their part. like his great fellow-worker in after life he was apprenticed to an apothecary, and like him also, he soon forsook this sphere of usefulness. desirous of better opportunities for the study of science, and overpowered by the miseries which war had brought upon the district of his birth, dumas persuaded his father to allow him to go to geneva. at geneva dumas found an atmosphere more suited to his scientific progress; chemistry, physics, botany, and other branches of natural science were taught by men whose names were everywhere known. he began experiments in chemistry with the crudest and most limited apparatus, but even with these he made discoveries which afterwards led to important work on the volumes occupied by the atoms of elementary substances. about the year dumas became acquainted with dr. j. l. prévost, who had returned from studying in many of the most famous medical schools of europe. invited by prévost to join in an investigation requiring medical, botanical and chemical knowledge, dumas now began a series of researches which soon passed into the domain of animal physiology, and by the prosecution of which under many difficulties he laid the foundations of his future fame. but along with his physiological work dumas carried on a research into the expansion of various ethers. this necessitated the preparation of a series of ethers in a state of purity; but so difficult did dumas find this to be, so much time did he consume in this preliminary work, and so interested did he become in the chemical part of the investigation, that he abandoned the experiments on expansion, and set himself to solve some of the problems presented by the composition and chemical properties of the ethers. dumas would probably have remained in geneva had he not had a morning visit paid him in the year . when at work in his laboratory one day, some one knocked and was bidden come in. "i was surprised to find myself face to face with a gentleman in a light-blue coat with metal buttons, a white waistcoat, nankeen breeches, and top-boots.... the wearer of this costume, his head somewhat bent, his eyes deep-set but keen, advanced with a pleasant smile, saying, 'monsieur dumas.' 'the same, sir; but excuse me.' 'i am m. de humboldt, and did not wish to pass through geneva without having had the pleasure of seeing you.'... i had only one chair. my visitor was pleased to accept it, whilst i resumed my elevated perch on the drawing stool.... 'i intend,' said m. de humboldt, 'to spend some days in geneva, to see old friends and to make new ones, and more especially to become acquainted with young people who are beginning their career. will you act as my cicerone? i warn you however that my rambles begin early and end late. now, could you be at my disposal, say from six in the morning till midnight?'" after some days spent as humboldt had indicated the great naturalist left geneva. dumas tells us that the town seemed empty to him. "i felt as if spell-bound. the memorable hours i had spent with that irresistible enchanter had opened a new world to my mind." dumas felt that he must go to paris--that there he would have more scope and more opportunities for prosecuting science. a few kind words, a little genuine sympathy, and a little help from humboldt were thus the means of fairly launching in their career of scientific inquiry these two young men, liebig and dumas. in paris, whither he went in , dumas found a welcome. he soon made the acquaintance and gained the friendship of the great men who then made natural science so much esteemed in the french capital. when the year came, it saw him professor of chemistry at the athenæum, and married to the lady whom he loved, and who has ever since fought the battle of life by his side. liebig left paris in . by the year he had perfected and applied that method for the analysis of organic compounds which is now in constant use wherever organic chemistry is studied; by the same year dumas had given the first warning of the attack which he was about to make on the great structure of dualism raised by berzelius. in a paper, "on some points of the atomic theory," published in , dumas adopted the distinction made by avogadro between molecules and atoms, or between the small particles of substances which remain undivided during physical actions, and the particles, smaller than these, which are undivided during chemical actions. but, unfortunately, dumas did not mark these two conceptions by names sufficiently definite to enable the readers of his memoir to bear the distinction clearly in mind. the terms "atom" and "molecule" were not introduced into chemistry with the precise meanings now attached to them until some time after . although the idea of two orders of small particles underlies all the experimental work described by dumas in this paper, yet the numbers which he obtained as representing the actual atomic weights of several elements--_e.g._ phosphorus, arsenic, tin, silicon--show that he had not himself carried out avogadro's hypothesis to its legitimate conclusions. two years after this dumas employed the reaction wherein two volumes of gaseous hydrochloric acid are produced by the union of one volume of hydrogen with one volume of chlorine, as an argument which obliged him to conclude that, if avogadro's physical hypothesis be accepted, the molecules of hydrogen and chlorine split, each into two parts, when these gases combine chemically. but dumas did not at this time conclude that the molecular weight of hydrogen must be taken as twice its atomic weight, and that--hydrogen being the standard substance--the molecular weights of all gases must be represented by the specific gravities of these gases, referred to hydrogen as . i have already shortly discussed the method for finding the relative weights of elementary atoms which is founded on avogadro's hypothesis, and, i think, have shown that this hypothesis leads to the definition of "atom" as the smallest amount of an element in one molecule of any compound of that element (see p. ). this deduction from avogadro's law is now a part and parcel of our general chemical knowledge. we wonder why it was not made by dumas; but we must remember that a great mass of facts has been accumulated since , and that this definition of "atom" has been gradually forced on chemists by the cumulative evidence of those facts. one thing dumas did do, for which the thanks of every chemist ought to be given him; he saw the need of a convenient method for determining the densities of compounds in the gaseous state, and he supplied this need by that simple, elegant and trustworthy method, still in constant use, known as _dumas's vapour density process_. while dumas was working out the details of this analytical method, which was destined to be so powerful an instrument of research, liebig was engaged in similar work; he was perfecting that process for the analysis of organic compounds which has since played so important a part in the advancement of this branch of chemical science. the processes in use during the first quarter of this century for determining the amounts of carbon, hydrogen, and oxygen in compounds of those elements, were difficult to conduct and gave untrustworthy results. liebig adopted the principle of the method used by lavoisier, viz. that the carbon in a compound can be oxidized, or burnt, to carbonic acid, and the hydrogen to water. he contrived a very simple apparatus wherein this burning might be effected and the products of the burning--carbonic acid and water--might be arrested and weighed. liebig's apparatus remains now essentially as it was presented to the chemical world in . various improvements in details have been made; the introduction of gas in place of charcoal as a laboratory fuel has given the chemist a great command over the process of combustion, but in every part of the apparatus to-day made use of in the laboratory is to be traced the impress of the master's hand. a weighed quantity of the substance to be analyzed is heated with oxide of copper in a tube of hard glass; the carbon is burnt to carbonic acid and the hydrogen to water at the expense of the oxygen of the copper oxide. attached to the combustion tube is a weighed tube containing chloride of calcium, a substance which greedily combines with water, and this tube is succeeded by a set of three or more small bulbs, blown in one piece of glass, and containing an aqueous solution of caustic potash, a substance with which carbonic acid readily enters into combination. the chloride of calcium tube and the potash bulbs are weighed before and after the experiment; the increase in weight of the former represents the amount of water, and the increase in weight of the latter the amount of carbonic acid obtained by burning a given weight of the compound under examination. as the composition of carbonic acid and of water is known, the amounts of carbon and of hydrogen in one hundred parts of the compound are easily found; the difference between the sum of these and one hundred represents the amount of oxygen in one hundred parts of the compound. if the compound should contain elements other than these three, those other elements are determined by special processes, the oxygen being always found by difference. soon after his settlement at giessen liebig turned his attention to a class of organic compounds known as the _cyanates_; but wöhler--who, while liebig was in paris in the laboratory of gay-lussac, was engaged in studying the intricacies of mineral chemistry under the guidance of berzelius--had already entered on this field of research. the two young chemists compared notes, recognized each other's powers, and became friends; this friendship strengthened as life advanced, and some of the most important papers which enriched chemical science during the next thirty years bore the joint signatures of liebig and wöhler. i have already mentioned that when it was found necessary to abandon the lavoisierian definition of organic chemistry as the chemistry of compounds containing carbon, hydrogen and oxygen, and sometimes also phosphorus or nitrogen, a definition was attempted to be based on the supposed fact that the formation of the compounds obtained from animals and plants could be accomplished only by the agency of a living organism. but the discovery made in by wöhler, that _urea_--a substance specially characterized by its production in the animal economy, and in that economy only--could be built up from mineral materials, rendered this definition of organic chemistry impossible, and broke down the artificial barrier whereby naturalists attempted to separate two fields of study between which nature made no division. we have here another illustration of the truth of the conception which underlies so many of the recent advances of science, which is the central thought of the noble structure reared by the greatest naturalist of our time, and which is expressed by one of the profoundest students of nature that this age has seen in the words i have already quoted from the preface to the "lyrical ballads," "in nature everything is distinct, but nothing defined into absolute independent singleness." from this time the progress of organic chemistry became rapid. dumas continued the researches upon ethers which he had commenced at geneva, and by the year or so he had established the relations which exist between ethers and alcohols on the one hand, and ethers and acids on the other. this research, a description of the details of which i cannot introduce here as it would involve the use of many technical terms and assume the possession by the reader of much technical knowledge, was followed by others, whereby dumas established the existence of a series of compounds all possessed of the chemical properties of alcohol, all containing carbon, hydrogen and oxygen, but differing from one another by a constant amount of carbon and hydrogen. this discovery of a series of alcohols, distinguished by the possession of certain definite properties whereby they were marked off from all other so-called organic compounds, was as the appearance of a landmark to the traveller in a country where he is without a guide. the introduction of the comparative method of study into organic chemistry--the method, that is, which bases classification on a comparison of large groups of compounds, and which seeks to gather together those substances which are like and to separate those which are unlike--soon began to bear fruit. this method suggested to the experimenter new points of view from which to regard groups of bodies; analogies which were hidden when a few substances only were considered, became prominent as the range of view was widened. what the gentle elia calls "fragments and scattered pieces of truth," "hints and glimpses, germs, and crude essays at a system," became important. there was work to be done, not only by the master spirits who, looking at things from a central position of vantage, saw the relative importance of the various detailed facts, but also by those who could only "beat up a little game peradventure, and leave it to knottier heads, more robust constitutions, to run it down." twenty years before the time of which we are now speaking davy had decomposed the alkalis potash and soda; as he found these substances to be metallic oxides, he thought it very probable that the other well-known alkali, ammonia, would also turn out to be the oxide of a metal. by the electrolysis of salts formed by the action of ammonia on acids, using mercury as one of the poles of the battery, davy obtained a strange-looking spongy substance which he was inclined to regard as an alloy of the metallic base of ammonia with mercury. from the results of experiments by himself and others, davy adopted a view of this alloy which regarded it as containing a _compound radicle_, or group of elementary atoms which in certain definite chemical changes behaved like a single elementary atom. to this compound radicle he gave the name of _ammonium_. as an aqueous solution of potash or soda was regarded as a compound of water and oxide of potassium or sodium, so an aqueous solution of ammonia was regarded as a compound of water and oxide of ammonium. when the composition of this substance, ammonium, came to be more accurately determined, it was found that it might be best represented as a compound atom built up of one atom of nitrogen and four atoms of hydrogen. the observed properties of many compounds obtained from ammonia, and the analogies observed between these and similar compounds obtained from potash and soda, could be explained by assuming in the compound atom (or better, in the molecule) of the ammonia salt, the existence of this group of atoms, acting as one atom, called ammonium. the reader will not fail to observe how essentially atomic is this conception of compound radicle. the ultimate particle, the molecule, of a compound has now come to be regarded as a structure built up of parts called atoms, just as a house is a structure built up of parts called stones and bricks, mortar and wood, etc. but there may be a closer relationship between some of the atoms in this molecule than between the other atoms. it may be possible to remove a group of atoms, and put another group--or perhaps another single atom--in the place of the group removed, without causing the whole atomic structure to fall to pieces; just as it may be possible to remove some of the bricks from the wall of a house, or a large wooden beam from beneath the lintels, and replace these by other bricks or by a single stone, or replace the large wooden beam by a smaller iron one, without involving the downfall of the entire house. the group of atoms thus removable--the compound radicle--may exist in a series of compounds. as we have an oxide, a sulphide, a chloride, a nitrate, etc., of sodium, so we may have an oxide, a sulphide, a chloride, a nitrate, etc., of ammonium. the compounds of sodium are possessed of many properties in common; this is partly explained by saying that they all contain one or more atoms of the element sodium. the compounds of ammonium possess many properties in common, and this is partly explained if we assume that they all contain one or more atoms of the compound radicle ammonium. the conception of compound radicle was carried by berzelius to its utmost limits. we have learned that the swedish chemist regarded every molecule as composed of two parts; in very many cases each of these parts was itself made up of more than one kind of atom--it was a compound radicle. but the berzelian system tended to become too artificial: it drifted further and further away from facts. of the two parts composing the dual molecular structure, one was of necessity positively, and the other negatively electrified. the greater number of the so-called organic compounds contained oxygen; oxygen was the most electro-negative element known; hence most organic compounds were regarded as formed by the coming together of one, two, or more atoms of oxygen, forming the negative part of the molecule, with one, two, or more atoms of a compound radicle, which formed the positive part of the molecule. from this dualistic view of the molecule there naturally arose a disposition to regard the compound radicles of organic chemistry as the non-oxygenated parts of the molecules of organic compounds. an organic compound came gradually to be regarded as a compound of oxygen with some other elements, which were all lumped together under the name of a compound radicle, and organic chemistry was for a time defined as the chemistry of compound radicles. from what has been said on p. , i think it will be evident that the idea of _substitution_ is a necessary part of the original conception of compound radicle; a group of atoms in a molecule may, it is said, be removed, and another group, or another atom, _substituted_ for that which is removed. berzelius adopted this idea, but he made it too rigid; he taught that an electro-negative atom, or compound radicle, could be replaced or substituted only by another electro-negative atom or group of atoms, and a positively electrified atom or group of atoms, only by another electro-positive atom or compound radicle. thus oxygen could perhaps be replaced by chlorine, but certainly not by hydrogen; while hydrogen might be replaced by a positively electrified atom, but certainly not by chlorine. the conceptions of compound radicles and of substitution held some such position in organic chemistry as that which i have now attempted to indicate when dumas and liebig began their work in this field. the visitors at one of the royal _soirées_ at the tuileries were much annoyed by the irritating vapours which came from the wax candles used to illuminate the apartments; dumas was asked to examine the candles and find the reason of their peculiar behaviour. he found that the manufacturer had used chlorine to bleach the wax, that some of this chlorine remained in the candles, and that the irritating vapours which had annoyed the guests of charles x. contained hydrochloric acid, produced by the union of chlorine with part of the hydrogen of the wax. candles bleached by some other means than chlorine were in future used in the royal palaces; and the unitary theory, which was to overthrow the dualism of berzelius, began to arise in the mind of dumas. the retention of a large quantity of chlorine by wax could scarcely be explained by assuming that the chlorine was present only as a mechanically held impurity. dumas thoroughly investigated the action of chlorine on wax and other organic compounds; and in he announced that hydrogen in organic compounds can be exchanged for chlorine, every volume of hydrogen given up by the original compound being replaced by an equal volume of chlorine. liebig and wöhler made use of a similar conception to explain the results which they had obtained about this time in their study of the oil of bitter almonds, a study which will be referred to immediately. the progress of this bold innovation made by dumas was much advanced by the experiments and reasonings of two french chemists, whose names ought always to be reverenced by students of chemistry as the names of a pair of brilliant naturalists to whom modern chemistry owes much. _gerhardt_ was distinguished by clearness of vision and expression; _laurent_ by originality, breadth of mind and power of speculation. laurent appears to have been the first who made a clear statement of the fundamental conception of the unitary theory: "many organic compounds, when treated with chlorine lose a certain number of equivalents of hydrogen, which passes off as hydrochloric acid. an equal number of equivalents of chlorine takes the place of the hydrogen so eliminated; thus the physical and chemical properties of the original substance are not profoundly changed. the chlorine occupies the place left vacant by the hydrogen; the chlorine plays in the new compound the same part as was played by the hydrogen in the original compound." the replacement of electro-positive hydrogen by electro-negative chlorine was against every canon of the dualistic chemistry; and to say that the physical and chemical properties of the original compound were not profoundly modified by this replacement, seemed to be to call in question the validity of the whole structure raised by the labours during a quarter of a century of one universally admitted to be among the foremost chemists of his age. but facts accumulated. by the action of chlorine on alcohol liebig obtained _chloroform_ and _chloral_, substances which have since been so largely applied to the alleviation of human suffering; but it was dumas who correctly determined the composition of these two compounds, and showed how they are related to alcohol and to one another. liebig's reception of the corrections made by dumas in his work furnishes a striking example of the true scientific spirit. "as an excellent illustration," said liebig, "of the mode in which errors should be corrected, the investigation of chloral by dumas may fitly be introduced. it carried conviction to myself, as i think to everybody else, not by the copious number of analytical data opposed to the not less numerous results which i had published, but because these data gave a simpler explanation both of the formation and of the changes of the substances in question." one of the most important contributions to the new views was made by dumas in his paper on the action of chlorine on acetic acid ( ), wherein he proved that the product of this action, viz. _trichloracetic acid_, is related to the parent substance by containing three atoms of chlorine in place of three atoms of hydrogen in the molecule; that the new substance is, like the parent substance, a monobasic acid; that its salts are very analogous in properties to the salts of acetic acid; that the action of the same reagents on the two substances is similar; and finally, that the existence of many derivatives of these compounds could be foretold by the help of the new hypothesis, which derivatives ought not to exist according to the dualistic theory, but which, unfortunately for that theory, were prepared and analyzed by dumas. i have alluded to a research by liebig and wöhler on oil of bitter almonds as marking an important stage in the advance of the anti-dualistic views. the paper alluded to was published in . at that time it was known that _benzoic acid_ is formed by exposure of bitter-almond oil to the air. liebig and wöhler made many analyses of these two substances, and many experiments on the mutual relations of their properties, whereby they were led to regard the molecules of the oil as built up each of an atom of hydrogen and an atom of a compound radicle--itself a compound of carbon, hydrogen and oxygen--to which they gave the name of _benzoyl_.[ ] benzoic acid they regarded as a compound of the same radicle with another radicle, consisting of equal numbers of oxygen and hydrogen atoms. by the action of chlorine and other reagents on bitter-almond oil these chemists obtained substances which were carefully analyzed and studied, and the properties of which they showed could be simply explained by regarding them all as compounds of the radicle _benzoyl_ with chlorine and other atoms or groups of atoms. but this view, if adopted, necessitated the belief that chlorine atoms could replace oxygen atoms; and, generally, that the substitution of an electro-positive by a negative atom or group of atoms did not necessarily cause any great alteration in the properties of the molecule. thus it was that the rigid conceptions of dualism were shown to be too rigid; that the possibility of an electro-positive radicle, or atom, replacing another of opposite electricity was recognized; and thus the view which regarded a compound molecule as one structure--atoms in which might be replaced by other atoms irrespective of the mutual electrical relations of these atoms--began to gain ground. from this time the molecule of a compound has been generally regarded as a unitary structure, as one whole, and the properties of the molecule as determined by the nature, number, and arrangement of all the atoms which together compose it. the unitary conception of a compound molecule appeared at first to be altogether opposed to the system of berzelius; but as time went on, and as fresh facts came to be known, it was seen that the new view conserved at least one, and that perhaps the most important, of the thoughts which formed the basis of the berzelian classification. underlying the dualism of berzelius was the conception of the molecule as an atomic structure; this was retained in the unitary system of dumas, gerhardt and laurent. berzelius had insisted that every molecule is a dual structure. this is taking too narrow a view of the possibilities of nature, said the upholders of the new school. _this_ molecule may have a dual structure; _that_ may be built up of three parts. the structure of this molecule or of that can be determined only by a careful study of its relations with other molecules. for a time it seemed also as if the new chemistry could do without the compound radicle which had been so much used by berzelius; but the pressure of facts soon drove the unitary chemists to recognize the value of that hypothesis which looked on parts of the molecule as sometimes more closely associated than other parts--which recognized the existence of atomic structures within the larger molecular structures. as a house is not simply a putting together of so many bricks, so much mortar, so many doors and windows, so many leaden pipes, etc., but rather a definite structure composed of parts, many of which are themselves also definite structures, such as the window and its accessory parts, the door with its lintel and handle, etc., so to the unitary chemists did the molecule appear to be built up of parts, some of which, themselves composed of yet smaller parts, discharged a particular function in the molecular economy. a general division of a plant might describe it as a structure consisting of a stem, a root, and leaves. each of the parts, directly by its individual action and indirectly by the mutual action between it and all the other parts, contributes to the growth of the whole plant; but if the stem, or root, or leaves be further analyzed, each is found to consist of many parts, of fibres and cells and tissue, etc. we may liken the plant to the molecule of an organic compound; the root, the stem and the leaves to the compound radicles of which this molecule is built up, and the tissue, fibres, etc., to the elementary atoms which compose these compound radicles. the molecule is one whole, possessed of definite structure and performing a definite function by virtue of the nature and the arrangement of its parts. many years elapsed after the publication of the researches of dumas, and of liebig and wöhler, before such a conception of the molecule as this was widely accepted by chemists. the opposition of the older school, headed by their doughty champion berzelius, had to be overcome; the infallibility of some of the younger members of the new school had to be checked; facts had to be accumulated, difficulties explained, weak analogies abandoned and strong ones rendered stronger by research; special views of the structure of this or that molecule, deduced from a single investigation, had to be supplemented and modified by wider views gained by the researches of many workers. it was not till that liebig, when asked by dumas at a dinner given during the french exhibition to the foreign chemists, why he had abandoned organic chemistry, replied that "now, with the theory of substitution as a foundation, the edifice may be built up by workmen: masters are no longer needed." laurent and gerhardt did noble work in advancing the unitary theory; to them is largely due the fruitful conception of types, an outcome of dumas's work, which owed its origin to the flickering of the wax candles in the tuileries during the royal _soirée_. chlorine can be substituted for hydrogen in acetic acid, and the product is closely related in its properties to the parent substance; various atoms or groups of atoms can be substituted by other groups in the derivatives of oil of bitter almonds, but a close analogy in properties runs through all these compounds: these facts might be more shortly expressed by saying that acetic and trichloracetic acids belong to the same _type_, and that the derivatives of bitter-almond oil likewise belong to one _type_. laurent carried this conception into inorganic chemistry. water and potash did not seem to have much in common, but laurent said potash is not a compound of oxide of potassium and water, it is rather a derivative of water. the molecule of potash is derived from that of water by replacing one atom of hydrogen in the latter by one atom of potassium; water and potash belong to the same type. thus there was constituted _the water type_. light was at once thrown on many facts in organic chemistry. the analogies between alcohol and water, some of which were first pointed out by graham (see p. ), seemed to follow as a necessary consequence when the molecule of alcohol was regarded as built on the water type. in place of two atoms of hydrogen combined with one of oxygen, there was in the alcohol molecule one atom of the compound radicle _ethyl_ (itself composed of carbon and hydrogen), one atom of oxygen and one of hydrogen. alcohol was water with one hydrogen atom substituted by one ethyl atom; the hydrogen atom was the atom of what we call an element, the ethyl was the atom of what we call a compound radicle. gerhardt sought to refer all organic compounds to one or other of three types--the water type, the hydrochloric acid type, and the ammonia type. as new compounds were prepared and examined, other types had to be introduced. to follow the history of this conception would lead us into too many details; suffice it to say that the theory of types was gradually merged in the wider theory of equivalency, about which i shall have a little to say in the next chapter. one result of the introduction of types into chemical science, associated as it was with the unitary view of compound radicles, was to overthrow that definition of organic chemistry which had for some time prevailed, and which stated that organic chemistry is "the chemistry of compound radicles." compound radicles, it is true, were more used in explaining the composition and properties of substances obtained from animals and vegetables than of mineral substances, but a definition of one branch of a science which practically included the other branch, from which the first was to be defined, could not be retained. chemists became gradually convinced that a definition of organic chemistry was not required; that there was no distinction between so-called organic and inorganic compounds; and they have consented, but i scarcely think will much longer consent, to retain the terms "organic" and "inorganic," only because these terms have been so long in use. the known compounds of the element carbon are so numerous, and they have been so much studied and so well classified, that it has become more convenient for the student of chemistry to consider them as a group, to a great extent apart from the compounds of the other elements; to this group he still often gives the name of "organic compounds." * * * * * liebig continued to hold the chair of chemistry in the university of giessen until the year , when he was induced by the king of bavaria to accept the professorship of the same science in the university of munich. during the second quarter of this century giessen was much resorted to by students of chemistry from all parts of the world, more especially from england. many men who afterwards made their mark in chemical discovery worked under the guidance of the professor of stockholm, but giessen has the honour of being the place where a well-appointed chemical laboratory for scientific research was first started as a distinctly educational institution. the fame of liebig as a discoverer and as a teacher soon filled the new institution with students, who were stirred to enthusiasm as they listened to his lectures, or saw him at work in his laboratory. "liebig was not exactly what is called a fluent speaker," says professor hofmann, of berlin, "but there was an earnestness, an enthusiasm in all he said, which irresistibly carried away the hearer. nor was it so much the actual knowledge he imparted which produced this effect, as the wonderful manner in which he called forth the reflective powers of even the least gifted of his pupils. and what a boon was it, after having been stifled by an oppressive load of facts, to drink the pure breath of science such as it flowed from liebig's lips! what a delight, after having perhaps received from others a sack full of dry leaves, suddenly in liebig's lectures to see the living, growing tree!... we felt then, we feel still, and never while we live shall we forget, liebig's marvellous influence over us; and if anything could be more astonishing than the amount of work he did with his own hands, it was probably the mountain of chemical toil which he got us to go through. each word of his carried instruction, every intonation of his voice bespoke regard; his approval was a mark of honour, and of whatever else we might be proud, our greatest pride of all was having him for our master.... of our young winnings in the noble playground of philosophical honour, more than half were free gifts to us from liebig, and to his generous nature no triumphs of his own brought more sincere delight than that which he took in seeing his pupils' success, and in assisting, while he watched, their upward struggle." liebig had many friends in england. he frequently visited this country, and was present at several meetings of the british association. at the meeting of he was asked to draw up a report on the progress of organic chemistry; he complied, and in presented the world with a book which marks a distinct epoch in the applications of science to industrial pursuits--"chemistry in its applications to agriculture and physiology." in this book, and in his subsequent researches and works,[ ] liebig established and enforced the necessity which exists for returning to the soil the nourishing materials which are taken from it by the growth of crops; he suggested that manure rich in the salts which are needed by plants might be artificially manufactured, and by doing this he laid the foundation of a vast industry which has arisen during the last two decades. he strongly and successfully attacked the conception which prevailed among most students of physiology at that time, that chemical and physical generalizations could not be applied to explain the phenomena presented by the growth of living organisms. he was among the first to establish, as an induction from the results of many and varied experiments, the canon which has since guided all teachers of the science of life, that a true knowledge of biology must be based on a knowledge of chemistry and physics. but liebig was not content to establish broad generalizations and to leave the working out of them to others; he descended from the heights of philosophical inquiry, and taught the housewife to make soup wherein the greatest amount of nourishment was conveyed to the invalid in the most easily digestible form; and has he not, by bringing within the reach of every one a portion of the animal nourishment which else had run to waste in the pampas of south america or the sheep-runs of australia, made his name, in every english home, familiar as a household word? on the death of berzelius in , it was to liebig that every chemist looked for a continuation of the annual report on the progress of chemistry, which had now become the central magazine of facts, whither each worker in the science could resort to make himself acquainted with what had been done by others on any subject which he proposed to investigate. from that time to the present day liebig's _annalen_ has been the leading chemical journal of the world. of the other literary work of liebig--of his essays, his celebrated "chemical letters," his many reports, his severe and sometimes harsh criticisms of the work of others--of the details of the three hundred original papers wherein he embodied the results of his researches, i have not time, nor would this be the place, to speak. honoured by every scientific society of any note in the world, crowned with the highest reward which england and france can offer to the man of science who is not an englishman or a frenchman--the copley medal and the associateship of the institute--honoured and respected by every student of science, loved by each of the band of ardent natures whom he had trained and sent forth to battle for the good of their race, and, best of all, working himself to the last in explaining the wonders of nature, he "passed into the silent land" on the th of april , leaving the memory of a life nobly devoted to the service of humanity, and the imperishable record of many truths added to the common stock of the race. * * * * * the life-work of dumas, other than that which i have already sketched, is so manifold and so varied, that to do more than refer to one or two leading points would carry us far beyond the limits within which i have tried to keep throughout this book. in one of his earliest papers dumas adopted the atomic theory as the corner-stone of his chemical system; he was thus led to an experimental revision of the values generally accepted for the atomic weights of some of the elements. among these revisions, that of the atomic weight of carbon holds a most important place, partly because of the excellency of the work, but more because of the other inquiries to which this work gave rise. dumas's experiments were summed up in the statement that the atom of carbon is twelve times heavier than the atom of hydrogen. the experimental methods and the calculations used in this determination involved a knowledge of the atomic weight of oxygen; in order accurately to determine the value to be assigned to this constant, dumas, in conjunction with boussingault, undertook a series of experiments on the synthesis of water, which forms one of the classical researches of chemistry, and wherein the number was established as representing the atomic weight of oxygen. stas, from experiments conducted at a later time with the utmost care and under conditions eminently fitted to gain accurate results, obtained the number · , in place of , for the atomic weight of oxygen; but in a paper recently published by the veteran dumas, a source of error is pointed out which stas had overlooked in his experiments, and it is shown that this error would tend slightly to increase the number obtained by stas. as the values assigned to the atomic weights of the elements are the very fundamental data of chemistry, and as we are every day more clearly perceiving that the mutual relations between the properties of elements and compounds are closely connected with the relative weights of the elementary atoms, we can scarcely lay too much stress on such work as this done by dumas and stas. not many years after the publication of dalton's "new system," the hypothesis was suggested by prout that the atomic weights of all the elements are represented by whole numbers--that of hydrogen being taken as unity--that the atom of each element is probably formed by the putting together of two, three, four, or more atoms of hydrogen, and that consequently there exists but a single elementary form of matter. among the upholders of this hypothesis dumas has held an important place. he modified the original statement of prout, and suggested that all atomic weights are whole multiples of half of that of hydrogen (that is, are whole multiples of / ). the experiments of stas seemed to negative this view, but later work--more especially the important critical revision of the results obtained by all the most trustworthy workers, conducted by professor clarke of cincinnati, and published by the smithsonian institution as part of their series of "constants of nature"--has shown that we are in no wise warranted by facts in rejecting prout's hypothesis as modified by dumas, but that the balance of evidence is at present rather in its favour. it would be altogether out of place to discuss here an hypothesis which leads to some of the most abstruse speculations as to the nature of matter in which chemists have as yet ventured to indulge. i mention it only because it illustrates the far-reaching nature of the researches of the chemist whose work we are now considering, and also because it shows the shallowness of the scoffs in which some partly educated people indulge when they see scientific men occupying themselves for years with attempts to solve such a minute and, as they say, trivial question as whether the number · or the number is to be preferred as representing the atomic weight of oxygen; "for in every speck of dust that falls lie hid the laws of the universe, and there is not an hour that passes in which you do not hold the infinite in your hand." another and very different subject, which has been placed on a firm basis by the researches of dumas, is the chemistry of fermentation. by his work on the action of beer-yeast on saccharine liquids, dumas proved liebig's view to be untenable--according to which the conversion of sugar into alcohol is brought about by the influence of chemical changes proceeding in the ferment; also that the view of berzelius, who regarded alcoholic fermentation as due simply to the contact of the ferment with the sugar, was opposed to many facts; and lastly, dumas showed that the facts were best explained by the view which regarded the change of sugar into alcohol as in no way different from other purely chemical changes, but as a change brought about, so far as our present knowledge goes, only by the agency of a growing organism of low form, such as yeast. in dumas established at his own expense a laboratory for chemical research. when the revolution of broke out dumas's means were much diminished, and he could no longer afford to maintain his laboratory. the closing of this place, where so much sound work had been done, was generally regarded as a calamity to science. about this time dumas received a visit from a person of unprepossessing appearance, who accosted him thus: "they assert that you have shut up your laboratory, but you have no right to do so. if you are in need of money, there," throwing a roll of bank-notes on the table, "take what you want. do not stint yourself; i am rich, a bachelor, and have but a short time to live." dumas's visitor turned out to be dr. jecker. he assured dumas that he was now only paying a debt, since he had made a fortune by what he had learnt in the medical schools of paris. dumas could not however in those troublous times turn his mind continuously to experimental research, and therefore declined dr. jecker's offer with many protestations of good will and esteem. new work now began to press upon dumas; his energy and his administrative powers were demanded by the state. elected a member of the national assembly in , he was soon called by the president of the republic to office as minister of agriculture and commerce. he was made a senator under the second empire. he entered the municipal council of paris about , and was soon elected to the presidency. under his presidency the great scheme for providing paris with spring-water carried by aqueducts and tunnels was successfully accomplished; many improvements were made in the drainage of the city; the cost of gas was decreased, while the quality was improved, the constancy of the supply insured, and the appliances for burning the gas in the streets were altered and rendered more effective. nominated to succeed pelouze as master of the mint in , dumas held this honourable and important position only until the franco-german war of . since that date he has relinquished political life; but as permanent secretary of the academy dumas now fills the foremost place in all affairs connected with science, whether pure or applied, in the french capital. in the work of these two chemists, liebig and dumas, we find admirable illustrations of the scientific method of examining natural appearances. in the broad general views which they both take of the phenomena to be studied, and the patient and persevering working out of details, we have shown us the combination of powers which are generally found in separate individuals. dumas has always insisted on the need of comparing properties and reactions of groups of bodies, before any just knowledge can be gained as to the position of a single substance in the series studied by the chemist. it has been his aim as a teacher, we are assured by his friend, professor hofmann, never to present to his students "an isolated phenomenon, or a notion not logically linked with others." to him each chemical compound is one in a series which connects it directly with many other similar compounds, and indirectly with other more or less dissimilar compounds. amid the overwhelming mass of facts which threaten nowadays to bury the science of chemistry, and crush the life out of it by their weight, dumas tracks his way by the aid of general principles; but these principles are themselves generalized from the facts, and are not the offspring of his own fancy. we have, i think, found that throughout the progress of chemical science two dangers have beset the student. he has been often tempted to accumulate facts, to amass analytical details, to forget that he is a chemist in his desire to perfect the instrument of analysis by the use of which he raises the scaffolding of his science; on the other hand, he has been sometimes allured from the path of experiment by his own day-dreams. the discoveries of science have been so wonderful, and the conceptions of some of those who have successfully prosecuted science have been so grand, that the student has not unfrequently been tempted to rest in the prevailing theories of the day, and, forgetting that these ought only "to afford peaceful lodgings to the intellect for the time," he has rather allowed them to circumscribe it, until at last the mind "finds difficulty in breaking down the walls of what has become its prison, instead of its home." we may think that dumas fell perhaps slightly into the former of these errors, when he did not allow his imagination a little more scope in dealing with the conception of "atom" and "molecule," the difference between which he had apprehended but not sufficiently marked by the year (see p. ). we know, from his own testimony, that liebig once fell into the latter error and that the consequences were disastrous. "i know a chemist"--meaning himself--"who ... undertook an investigation of the liquor from the salt-works. he found iodine in it, and observed, moreover, that the iodide of starch turned a fiery yellow by standing over-night. the phenomenon struck him; he saturated a large quantity of the liquor with chlorine, and obtained from this, by distillation, a considerable quantity of a liquid which coloured starch yellow, and externally resembled chloride of iodine, but differed from this compound in many properties. he explained, however, every discrepancy with satisfaction to himself; he contrived for himself a theory. several months later, he received a paper of m. balard's," announcing the discovery of bromine, "and on that same day he was able to publish the results of experiments on the behaviour of bromine with iron, platinum, and carbon; for balard's bromine stood in his laboratory, labelled _liquid chloride of iodine_. since that time he makes no more theories unless they are supported and confirmed by trustworthy experiments; and i can positively assert that he has not fared badly by so doing." another point which we notice in the life-work of these two chemists is their untiring labour. they were always at work; wherever they might be, they were ready to notice passing events or natural phenomena, and to draw suggestions from these. as davy proved the elementary character of iodine and established many of the properties of this substance during a visit to paris, so we find dumas making many discoveries during brief visits paid to his friends' laboratories when on excursions away from paris. during a visit to aix-les-bains, he noticed that the walls of the bath-room were covered with small crystals of sulphate of lime. the waters of the bath, he knew, were charged with sulphuretted hydrogen, but they contained no sulphuric acid, nor could that acid be detected in the air of the bath-rooms. this observation was followed up by experiments which proved that a porous material, such as a curtain or an ordinary plastered wall, is able to bring about the union of oxygen with sulphuretted hydrogen, provided moisture be present and a somewhat high temperature be maintained. again, we find liebig and dumas characterized by great mental honesty. "there is no harm in a man committing mistakes," said liebig, "but great harm indeed in his committing none, for he is sure not to have worked.... an error you have become cognizant of, do not keep in your house from night till morning." students of science, more than any other men, ought to be ready to acknowledge and correct the errors into which they fall. it is not difficult for them to do this: they have only to be continually going to nature; for there they have a court of appeal always ready to hear their case, and to give an absolutely unbiased judgment: they have but to bring their theories and guesses to this judge to have them appraised at their true value. footnotes: [ ] "in reviewing once more the facts elicited by our inquiry, we find them arranged around a common centre, a group of atoms preserving intact its nature, amid the most varied associations with other elements. this stability, this analogy, pervading all the phenomena, has induced us to consider this group as a sort of compound element, and to designate it by the special name of _benzoyl_."--liebig and wöhler, . [ ] "animal chemistry, or chemistry in its applications to physiology and pathology," . "researches on the chemistry of food," . "the natural laws of husbandry," . chapter vii. modern chemistry. on p. i referred to the work of the german chemist richter, by which the _equivalents_ of certain acids and bases were established. those quantities of various acids which severally neutralized one and the same quantity of a given base, or those quantities of various bases which severally neutralized one and the same quantity of a given acid, were said to be equivalent. these were the quantities capable of performing a certain definite action. in considering the development of dumas's substitution theory, we found that laurent retained this conception of equivalency when he spoke of an equivalent of hydrogen being replaced by an equivalent of chlorine (see p. ). a certain weight of chlorine was able to take the place and play the part of a certain weight of hydrogen in a compound; these weights, of hydrogen and chlorine, were therefore equivalent. this conception has been much used since laurent's time, but it has for the most part been applied to the atoms of the elements. hydrogen being taken as the standard substance, the elements have been divided into groups, in accordance with the number of hydrogen atoms with which one atom of each element is found to combine. thus certain elements combine with hydrogen only in the proportion of one atom with one atom; others combine in the proportion of one atom with two atoms of hydrogen; others in the proportion of one atom with three atoms of hydrogen, and so on. the adjective _monovalent_, _divalent_, _trivalent_, etc., is prefixed to an element to denote that the atom of this element combines with one, or two, or three, etc., atoms of hydrogen to form a compound molecule. let us consider what is implied in this statement--"the nitrogen atom is trivalent." this statement, if amplified, would run thus: "one atom of nitrogen combines with three atoms of hydrogen to form a compound molecule." now, this implies ( ) that the atomic weight of nitrogen is known, and ( ) that the molecular weight, and the number of nitrogen and hydrogen atoms in the molecule, of a compound of nitrogen and hydrogen are also known. but before the atomic weight of an element can be determined, it is necessary (as we found on p. ) to obtain, analyze, and take the specific gravities of a series of gaseous compounds of that element. the smallest amount of the element (referred to hydrogen as unity) in the molecule of any one of these gases will then be the atomic weight of the element. when it is said that "the molecular weight, and the number of nitrogen and hydrogen atoms in the molecule, of a compound of nitrogen and hydrogen are known," the statement implies that the compound in question has been obtained in a pure state, has been analyzed carefully, has been gasefied, and that a known volume of the gas has been weighed. when therefore we say that "the nitrogen atom is trivalent," we sum up a large amount of knowledge which has been gained by laborious experiment. this classification of the elements into groups of equivalent atoms--which we owe to frankland, williamson, odling, and especially to kekulé--has been of much service especially in advancing the systematic study of the compounds of carbon. it helps to render more precise the conception which has so long been gaining ground of the molecule as a definite structure. a monovalent element is regarded as one the atom of which acts on and is acted on by only one atom of hydrogen in a molecule; a divalent as one, the atom of which acts on and is acted on by two atoms of hydrogen--or other monovalent element--in a molecule; a trivalent element as one, the atom of which acts on and is acted on by three atoms of hydrogen--or other monovalent element--in a molecule; and so on. the fact that there often exist several compounds of carbon, the molecules of which are composed of the same numbers of the same atoms, finds a partial explanation by the aid of this conception of the elementary atom as a little particle of matter capable of binding to itself a certain limited number of other atoms to form a compound molecule. for if the observed properties of a compound are associated with a certain definite arrangement of the elementary atoms within the molecules of that compound, it would seem that any alteration in this arrangement ought to be accompanied by an alteration in the properties of the compound; in other words, the existence of more than one compound of the same elements united in the same proportions becomes possible and probable. i have said that such compounds exist: let me give a few examples. the alchemists poured a stream of mercury on to molten sulphur, and obtained a black substance, which was changed by heat into a brilliantly red-coloured body. we now know that the black and the red compounds alike contain only mercury and sulphur, and contain these elements united in the same proportions. hydrogen, carbon, nitrogen and oxygen unite in certain proportions to produce a mobile, colourless, strongly acid liquid, which acts violently on the skin, causing blisters and producing great pain: if this liquid is allowed to stand for a little time in the air it becomes turbid, begins to boil, gets thicker, and at last explodes, throwing a white pasty substance about in all directions. this white solid is inodorous, is scarcely acid to the taste, and does not affect the skin; yet it contains the same elements, united in the same proportions, as were present in the strongly acid, limpid liquid from which it was produced. two substances are known each containing carbon and hydrogen united in the same proportions: one is a gas with strong and irritating odour, and exerting a most disagreeable action on the eyes; the other is a clear, limpid, pleasant-smelling liquid. phosphorus is a very poisonous substance: it readily takes fire in the air at ordinary temperatures, so that it must be kept under water; but a modification of phosphorus is known, containing no form of matter other than phosphorus, which is non-poisonous, does not take fire easily, and may be handled with safety. once more, there is a compound of nitrogen and oxygen which presents the appearance of a deep-red, almost black gas; there is also a compound of nitrogen and oxygen which is a clear, colourless gas; yet both contain the same elements united in the same proportions. but a detailed consideration of _isomerism_, _i.e._ the existence of more than one compound built up of the same amounts of the same elements yet possessing different properties, would lead us too far from the main path of chemical advance which we wish to trace. the chemist is to-day continually seeking to connect the properties of the bodies he studies with the molecular structures of these bodies; the former he can observe, a knowledge of the latter he must gain by reasoning on the results of operations and experiments. his guide--the guide of lavoisier and his successors--is this: "similarity of properties is associated with similarity of composition"--by "composition" he generally means molecular composition. many facts have been amassed of late years which illustrate the general statement that the properties of bodies are connected with the composition of those bodies. thus a distinct connection has been traced between the tinctorial power and the molecular composition of certain dye-stuffs; in some cases it has even become possible to predict how a good dye-stuff may be made--to say that, inasmuch as this or that chemical reaction will probably give rise to the production of this or that compound, the atoms in the molecule of which we believe to have a certain arrangement relatively to one another, so this reaction or that will probably produce a dye possessed of strong tinctorial powers. the compound to the presence of which madder chiefly owes its dyeing powers is called _alizarine_; to determine the nature of the molecular structure of this compound was, for many years, the object of the researches of chemists; at last, thanks especially to the painstaking zeal of two german chemists, it became fairly clear that alizarine and a compound of carbon and hydrogen, called _anthracene_, were closely related in structure. anthracene was obtained from alizarine, and, after much labour, alizarine was prepared from anthracene. anthracene is contained in large quantities in the thick pitch which remains when coal-tar is distilled; this pitch was formerly of little or no value, but as soon as the chemical manufacturer found that in this black objectionable mass there lay hidden enormous stores of alizarine, he no longer threw away his coal-tar pitch, but sold it to the alizarine manufacturer for a large sum. thus it has come to pass that little or no madder is now cultivated; madder-dyeing is now done by means of alizarine made from coal-tar: large tracts of ground, formerly used for growing the madder plant, are thus set free for the growth of wheat and other cereals. this discovery of a method for preparing alizarine artificially stimulated chemists to make researches into the chemical composition, and if possible to get to know something about the molecular structure of indigo. those researches have very recently resulted in the knowledge of a series of reactions whereby this highly valuable and costly dye-stuff may be prepared from certain carbon compounds which, like anthracene, are found in coal-tar. these examples, while illustrating the connection that exists between the composition and the properties of bodies, also illustrate the need there is for giving a scientific chemical training to the man who is to devote his life to chemical manufactures. pure and applied science are closely connected; he who would succeed well in the latter must have a competent and a practical knowledge of the former. that composition--molecular composition--and properties are closely related is generally assumed, almost as an axiom, in chemical researches nowadays. lavoisier defined acids as substances containing oxygen; davy regarded an acid as a compound the properties of which were conditioned by the nature and by the arrangement of all the elements which it contained; liebig spoke of acids as substances containing "replaceable" hydrogen; the student of the chemistry of the carbon compounds now recognizes in an organic acid a compound containing hydrogen, but also carbon and oxygen, and he thinks that the atoms of hydrogen (or some of these atoms) in the molecule of such a compound are, in some way, closely related to atoms of oxygen and less closely to atoms of carbon, within that molecule,--in other words, the chemist now recognizes that, for carbon compounds at any rate, acids are acid not only because they contain hydrogen, but also because that hydrogen is related in a definite manner within the molecule to other elementary atoms; he recognizes that the acid or non-acid properties of a compound are conditioned, not only by the nature of the elements which together form that compound, but also by the arrangement of these elements. davy's view of the nature of acids is thus confirmed and at the same time rendered more definite by the results of recent researches. the physical student is content to go no further than the molecule; the properties of bodies which he studies are regarded, for the most part, as depending on the size, the nature, and perhaps the grouping together of molecules. but the chemist seeks to go deeper than this. the molecule is too large a piece of matter for him; the properties which he studies are conceived by him to be principally conditioned by the nature, the number, and the arrangement of the parts of the molecule--of the atoms which together build up the molecule. in these elementary atoms he has, for the present, found the materials of which the heavens and the earth are made; but facts are being slowly gained which render it probable that these atoms are themselves structures--that they are built up of yet smaller parts, of yet simpler kinds of matter. to gather evidence for or against this supposition, the chemist has been obliged to go from the earth to the heavens, he has been obliged to form a new science, the science of spectroscopic analysis. this subject has been considered in "the astronomers," belonging to this series of books; but the point of view from which the matter is there regarded is astronomical rather than chemical. i should like briefly to recall to the reader the fundamental facts of this branch of science. [illustration: fig. .] when a ray of light is allowed to pass through a glass prism and then fall on to a white surface, the image produced on this surface consists of a many-coloured band of light. the blue or violet part of this band is more bent away from the plane of the entering ray than the orange part, and the latter more than the red part of the band. this is roughly represented in fig. , where _r_ is the ray of light passing through the prism p, and emerging as a sevenfold band of coloured lights, of which the violet, v, is most, and the red band, r, is least bent away from the plane of the ray _r_. if the surface--say a white screen--on which the many-coloured band of light, or _spectrum_, falls, is punctured by a small hole, so as to admit the passage of the violet, or blue, or orange, or red light only, and if this violet, etc., light is then passed through a second prism, no further breaking up of that light takes place. this state of matters is represented in the part of the figure towards the right hand, where the red ray, r, is shown as passing through the screen, and falling on to a second prism, p': the red ray is slightly bent out of its direct course, but is not subdivided; it falls on the second screen as a ray of red light, r'. but if a quantity of the metal sodium is vaporized in a hot non-luminous flame, and if the yellow light thus produced is passed through a prism, a spectrum is obtained consisting of a single yellow line (on a dark background), situated on that part of the screen where the orange-yellow band occurred when the ray of sunlight was split up by the action of the prism. in fig. the yellow light from a flame containing sodium is represented by the line y. the light emitted by the glowing sodium vapour is said to be _monochromatic_. [illustration: fig. ] lastly, if the experiment is arranged so that a ray of sunlight or of light from an electric lamp passes through a layer of comparatively cool sodium vapour before reaching the prism, a spectrum is produced corresponding to the solar spectrum except that a black line appears in the position where the yellow line, characteristic of sodium, was noticed in the second experiment. [illustration: fig. .] fig. represents the result of this experiment: the ray of sunlight or electric light, _r_, passes through a quantity of sodium vapour, and is then decomposed by the prism; the spectrum produced is marked by the absence of light (or by a dark line) where the yellow line, y, was before noticed. these are the fundamental facts of spectroscopic analysis: sunlight is decomposable into a band of many colours, that is, into a spectrum; light emitted by a glowing vapour is characterized by the presence of coloured lines, each of which occupies a definite position with reference to the various parts of the solar spectrum; sunlight--or the electric light--when allowed to pass through a mass of vapour, furnishes a spectrum characterized by the absence of those bright lines, the presence of which marked the spectrum of the light obtained by strongly heating the vapour through which the sunlight has passed. the spectrum obtained by decomposing the light emitted by glowing vapour of potassium is characterized by the presence of certain lines--call them a and b lines. we are asked what element (or elements) is present in a certain gas presented to us: we pass a beam of white light through this gas and then through a prism, and we obtain a continuous spectrum (_i.e._ a spectrum of many colours like the solar spectrum) with two dark lines in the same positions as those occupied by the lines a and b. we therefore conclude that the gas in question contains vapour of potassium. the solar spectrum, when carefully examined, is found to be crossed by a very large number of fine black lines; the exact positions of many hundreds of these lines have been carefully determined, and, in most cases, they are found to correspond to the positions of various bright lines noticed in the spectra of the lights emitted by hot vapours of various elementary bodies. assume that the sun consists, broadly speaking, of an intensely hot and luminous central mass, formed to a large extent of the elementary substances which build up this earth, and that this central mass is surrounded by a cooler (but yet very hot) gaseous envelope of the same elements,--and we have a tolerably satisfactory explanation of the principal phenomena revealed by the spectroscopic study of the sun's light. on this assumption the central mass of glowing iron, chromium, magnesium, nickel, cobalt, hydrogen, etc., is sending out light; a portion of the light emitted by the glowing iron is quenched as it passes through a cloud of cooler iron vapour outside the central mass, a portion of the light emitted by the glowing chromium is quenched as it passes through a cloud of cooler chromium vapour, and so on; the black lines in the spectrum are the records of these various quenchings of this and that light. so far then the study of the solar spectrum appears to be tolerably simple, and this study generally confirms the proposition that the material of which the sun is composed is, broadly, identical with those forms of matter which we, on this earth, call the chemical elements. but whatever be the composition of the sun, it is, i think, evident that in dealing with a ray of light coming therefrom, we are dealing with a very complex phenomenon. according to the hypothesis which is now guiding us, the solar light which passes into our spectroscope has probably had its beginning in some central part of the sun, and has passed through very thick layers of hot metallic clouds, agitated perhaps by solar cyclones. could we examine the light coming from some defined part of the sun, we should probably obtain valuable information. during a solar eclipse red prominences are seen projecting beyond the dark shadow of the moon, which covers the sun's disc. analysis of the light emitted by these prominences has shown that they are phenomena essentially belonging to the sun itself, and that they consist of vast masses of intensely hot, glowing gaseous substances, among which hydrogen is present in large quantities. that these prominences are very hot, hotter than the average temperature of the ordinary solar atmosphere, is proved by the fact that the spectrum of the light coming from them is characterized by bright lines. by special arrangements which need not be discussed here, but which have been partly explained in "the astronomers" (see pp. , of that book), it has been shown that these prominences are in rapid motion: at one moment they shoot up to heights of many thousand miles, at another they recede towards the centre of the sun. we thus arrive at a picture of the solar atmosphere as consisting of layers of very hot gases, which are continually changing their relative positions and forms; sometimes ejections of intensely hot, glowing gases occur,--we call these prominences; sometimes down-rushes of gaseous matter occur,--we call these spots. among the substances which compose the gaseous layers we recognize hydrogen, iron, magnesium, sodium, nickel, chromium, etc., but we also find substances which can at present be distinguished only by means of the wave-lengths of the light which they emit; thus we have stuff, stuff, stuff, etc. let us now turn to another part of this subject. by a special arrangement of apparatus it is possible to observe the spectrum of the light emitted by a glowing vapour, parts of which are hotter than other parts, and to compare the lines in the spectrum of the light coming from the hottest parts with the lines in the spectrum of the light coming from the cooler parts of the vapour. if this is done for sodium vapour, certain lines are apparent in all the spectra, others only in the spectrum of the light coming from the hottest parts of the sodium vapour: the former lines are called "long lines," the latter "short lines." a rough representation of the long and short lines of sodium is given in fig. . [illustration: fig. .--long and short lines of sodium.] now, suppose that the lines in the spectrum of the light emitted by glowing manganese vapour have been carefully mapped, and classed as long and short lines: suppose that the same thing has been done for the iron lines: now let a little manganese be mixed with much iron, let the mixture be vaporized, and let the light which is emitted be decomposed by the prism of a spectroscope, it will be found that the long lines of manganese alone make their appearance; let a little more manganese be added to the mixture, and now some of the shorter lines due to manganese begin to appear in the spectrum. hence it has been concluded by lockyer that if the spectrum of the light emitted by the glowing vapour of any element--call it a--is free from the long lines of any other element--say element b--this second element is not present as an impurity in the specimen of element a which is being examined. lockyer has applied this conclusion to "purify" various elementary spectra. the spectrum of element a is carefully mapped, and the lines are divided into long and short lines, according as they are noticed in the spectrum of the light coming from all parts of the glowing vapour of a, or only in the spectrum of the light which comes from the hotter parts of that vapour. the spectra of elements b and c are similarly mapped and classified: then the three spectra are compared; the longest line in the spectrum of b is noted, if this line is found in the spectrum of a, it is marked with a negative sign--this means that so far as the evidence of this line goes b is present as an impurity in a; the next longest b line is searched for in the spectrum of a--if present it also is marked with a negative sign; a similar process of comparison and elimination is conducted with the spectra of a and c. in this way a "purified" spectrum of the light from a is obtained--a spectrum, that is, from which, according to lockyer, all lines due to the presence of small quantities of b and c as impurities in a have been eliminated. [illustration: fig. .] fig. is given in order to make this "purifying" process more clearly understood. but when this process has been completed there remain, in many cases, a few short lines common to two or more elementary spectra: such lines are called by lockyer _basic lines_. he supposes that these lines are due to light emitted by forms of matter simpler than our elements; he thinks that at very high temperatures some of the elements are decomposed, and that the _bases_ of these elements are produced and give out light, which light is analyzed by the spectroscope. such short basic lines are marked in the spectra represented in fig. with a positive sign. now, if the assumption made by lockyer be admitted, viz. that the short lines, or some of the short lines, which are coincident in the "purified" spectra of various elements, are really due to light emitted by forms of matter into which our so-called elements are decomposed at very high temperatures, it follows that such lines should become more prominent in the spectra of the light emitted by elements the higher the temperature to which these elements are raised. but we know (see p. ) that the prominences around the sun's disc are hotter than the average temperature of the solar atmosphere; hence the spectrum of the light coming from these prominences ought to be specially rich in "basic" lines: this supposition is confirmed by experiment. lockyer has also shown that it is the "basic," and not the long lines, which are especially affected in the spectra of light coming from those parts of the solar atmosphere which are subjected to the action of cyclones, _i.e._ which are at abnormally high temperatures. and finally, a very marked analogy has been established between the changes in the spectrum of the light emitted by a compound substance as the temperature is raised, and the substance is gradually decomposed into its elements, and the spectrum of the light emitted by a so-called elementary substance as the temperature of that substance is increased. but it may be urged that lockyer's method of "purifying" a spectrum is not satisfactory; that, although all the longer lines common to two spectra are eliminated, the coincident short lines which remain are due simply to very minute quantities of one element present as an impurity in the larger quantity of the other. further, it has been shown that several of the so-called "basic" lines are resolved, by spectroscopes of great dispersive power, into groups of two or more lines, which lines are not coincident in different spectra. and moreover it is possible to give a fairly satisfactory explanation of the phenomena of solar chemistry without the aid of the hypothesis that our elements are decomposed in the sun into simpler forms of matter. nevertheless this hypothesis has a certain amount of experimental evidence in its favour; it may be a true hypothesis. i do not think we are justified at present either in accepting it as the best guide to further research, or in wholly rejecting it. the researches to which this hypothesis has given rise have certainly thrown much light on the constitution of the sun and stars, and they have also been instrumental in forcing new views regarding the nature of the elements on the attention of chemists, and so of awakening them out of the slumber into which every class of men is so ready to fall. the tale told by the rays of light which travel to this earth from the sun and stars has not yet been fully read, but the parts which the chemist has spelt out seem to say that, although the forms of matter of which the earth is made are also those which compose the sun and stars, yet in the sun and stars some of the earthly elements are decomposed, and some of the earthly atoms are split into simpler forms. the tale, i say, told by the rays of light seems to bear this interpretation, but it is written in a language strange to the children of this earth, who can read it as yet but slowly; for the name given to the new science was "_ge-urania_, because its production was of earth and heaven. and it could not taste of death, by reason of its adoption into immortal palaces; but it was to know weakness, and reliance, and the shadow of human imbecility; and it went with a lame gait; but in its going it exceeded all mortal children in grace and swiftness." there are certain little particles so minute that at least sixty millions of them are required to compose the smallest portion of matter which can be seen by the help of a good microscope. some of these particles are vibrating around the edge of an orb a million times larger than the earth, but at a distance of about ninety millions of miles away. the student of science is told to search around the edge of the orb till he finds these particles, and having found them, to measure the rates of their vibrations; and as an instrument with which to do this he is given--a glass prism! but he has accomplished the task; he has found the minute particles, and he has measured their vibration-periods. chemistry is no longer confined to this earth: the chemist claims the visible universe as his laboratory, and the sunbeams as his servants. davy decomposed soda and potash by using the powerful instrument given him by volta; but the chemist to-day has thrown the element he is seeking to decompose into a crucible, which is a sun or a star, and awaits the result. the alchemists were right. there is a philosopher's stone; but that stone is itself a compound of labour, perseverance, and genius, and the gold which it produces is the gold of true knowledge, which shall never grow dim or fade away. chapter viii. summary and conclusion. we have thus traced some of the main paths along which chemistry has advanced since the day when, ceasing to be guided by the dreams of men who toiled with but a single idea in the midst of a world of strange and complex phenomena, she began to recognize that nature is complex but orderly, and so began to be a branch of true knowledge. in this review we have, i think, found that the remark made at the beginning of the introductory chapter is, on the whole, a just one. that the views of the alchemists, although sometimes very noble, were "vague and fanciful" is surely borne out by the quotations from their writings given in the first chapter. this period was followed by that wherein the accurate, but necessarily somewhat narrow conception of the lavoisierian chemistry prevailed. founded for the most part on the careful, painstaking, and quantitative study of one phenomenon--a very wide and far-reaching phenomenon, it is true--it was impossible that the classification introduced by the father of chemical science should be broad enough to include all the discoveries of those who came after him. but although this classification had of necessity to be revised and recast, the genius of lavoisier enunciated certain truths which have remained the common possession of every chemical system. by proving that however the forms of matter may be changed the mass remains unaltered, he for the first time made a science of chemistry possible. he defined "element" once for all, and thus swept away the fabric of dreams raised by the alchemists on the visionary foundation of _earth_, _air_, _fire_ and _water_, or of _mercury_, _sulphur_ and _salt_. by his example, he taught that weighings and measurements must be made before accurate knowledge of chemical reactions can be hoped for; and by his teaching about oxygen being _the acidifier_--although we know that this teaching was erroneous in many details--he showed the possibility of a system of classification of chemical substances being founded on the actually observed properties and composition of those substances. lavoisier gained these most important results by concentrating his attention on a few subjects of inquiry. that chemistry might become broad it was necessary that it should first of all become narrower. the period when the objects of the science were defined and some of its fundamental facts and conceptions were established, was succeeded, as we saw in our sketch, by that in which dalton departed somewhat from the method of investigation adopted by most masters in science, and by concentrating his great mental powers on facts belonging to one branch of natural knowledge, elaborated a simple but very comprehensive theory, which he applied to explain the facts belonging to another branch of science. chemistry was thus endowed with a grand and far-reaching conception, which has been developed and applied by successive generations of investigators: but we must not forget that it was the thorough, detailed work of black and lavoisier which made possible the great theory of dalton. at the time when dalton was thinking out his theory of atoms, davy was advancing as a conqueror through the rich domain which the discovery of volta had opened to chemistry. dalton, trained to rely on himself, surrounded from his youth by an atmosphere in which "sweetness and light" did not predominate, thrown on the world at an early age, and obliged to support himself by the drudgery of teaching when he would fain have been engaged in research, and at the same time--if we may judge from his life as recorded by his biographers--without the sustaining presence of such an ideal as could support the emotional part of his nature during this time of struggle,--dalton, we found, withdrew in great part from contact with other scientific workers, and communing only with himself, developed a theory which, while it showed him to be one in the chain of thinkers that begins in democritus and leucippus, was nevertheless stamped with the undeniable marks of his own individuality and genius, and at the same time was untouched by any of the hopes or fears, and unaffected by any of the passions, of our common humanity. davy, on the other hand, was surrounded from childhood by scenes of great natural beauty and variety, by contact with which he was incited to eager desire for knowledge, while at the same time his emotions remained fresh and sensitive to outward impressions. entering on the study of natural science when there was a pause in the march of discovery, but a pause presageful of fresh advances, he found outward circumstances singularly favourable to his success; seizing these favourable circumstances he made rapid advances. like lavoisier, he began his work by proving that there is no such thing in nature as transmutation, in the alchemical meaning of the term; as lavoisier had proved that water is not changed into earth, so did davy prove that acid and alkali are not produced by the action of the electric current on pure water. we have shortly traced the development of the electro-chemical theory which davy raised on the basis of experiment; we have seen how facts obliged him to doubt the accepted view of the composition of hydrochloric acid and chlorine, and how by the work he did on these subjects chemists have been finally convinced that an element is not a substance which _cannot be_, but a substance which _has not been_ decomposed, and how from this work has also arisen the modern theory of acids, bases and salts. we found that, by the labours of the great swede j. j. berzelius, the daltonian theory was confirmed by a vast series of accurate analyses, and, in conjunction with a modification of the electro-chemical theory of davy, was made the basis of a system of classification which endeavoured to include all chemical substances within its scope. the atom was the starting-point of the berzelian system, but that chemist viewed the atom as a dual structure the parts of which held together by reason of their opposite electrical polarities. berzelius, we saw, greatly improved the methods whereby atomic weights could be determined, and he recognized the importance of physical generalizations as aids in finding the atomic weights of chemical substances. but berzelius came to believe too implicitly in his own view of nature's working; his theory became too imperious. chemists found it easier to accept than to doubt an interpretation of facts which was in great part undeniably true, and which formed a central luminous conception, shedding light on the whole mass of details which, without it, seemed confused and without meaning. if the dualistic stronghold was to be carried, the attack should be impetuous, and should be led by men, not only of valour, but also of discretion. we found that two champions appeared, and that, aided by others who were scarcely inferior soldiers to themselves, they made the attack, and made it with success. but when the heat of the battle was over and the bitterness of the strife forgotten, it was found that, although many pinnacles of the dualistic castle had been shattered, the foundation and great part of the walls remained; and, strange to say, the men who led the attack were content that these should remain. the atom could no longer be regarded as always composed of two parts, but must be looked on rather as one whole, the properties of which are defined by the properties and arrangements of all its parts; but the conception of the atom as a structure, and the assurance that something could be inferred regarding that structure from a knowledge of the reactions and general properties of the whole, remained when dumas and liebig had replaced the dualism of berzelius by the unitary theory of modern chemistry; and these conceptions have remained to the present day, and are now ranked among the leading principles of chemical science; only we now speak of the "molecule" where berzelius spoke of the "atom." along with these advances made by dumas, liebig and others in rendering more accurate the general conception of atomic structure, we found that the recognition of the existence of more than one order of small particles was daily gaining ground in the minds of chemists. the distinction between what we now call atoms and molecules had been clearly stated by avogadro in ; but the times were not ripe. the mental surroundings of the chemists of that age did not allow them fully to appreciate the work of avogadro. the seed however was sown, and the harvest, although late, was plentiful. we saw that dumas accepted, with some hesitation, the distinction drawn by avogadro, but that failing to carry it to its legitimate conclusion, he did not reap the full benefit of his acceptance of the principle that the smallest particle of a substance which takes part in a physical change divides into smaller particles in those changes which we call chemical. to gerhardt and laurent we owe the full recognition, and acceptance as the foundation of chemical classification, of the atom as a particle of matter distinct from the molecule; they first distinctly placed the law of avogadro--"equal volumes of gases contain equal numbers of molecules"--in its true position as a law, which, resting on physical evidence and dynamical reasoning, is to be accepted by the chemist as the basis of his atomic theory. to the same chemists we are indebted for the formal introduction into chemical science of the conception of types, which, as we found, was developed by frankland, kekulé, and others, into the modern doctrine of equivalency of groups of elementary atoms. we saw that, in the use which he made of the laws of mitscherlich, and of dulong and petit, berzelius recognized the importance of the aid given by physical methods towards solving the atomic problems of chemistry; but among those who have most thoroughly availed themselves of such aids graham must always hold a foremost place. graham devoted the energies of his life to tracking the movements of atoms and molecules. he proved that gases pass through walls of solid materials, as they pass through spaces already occupied by other gases; and by measuring the rapidities of these movements he showed how it was possible to determine the rate of motion of a particle of gas so minute that a group of a hundred millions of them would be invisible to the unassisted vision. graham followed the molecules as in their journeyings they came into contact with animal and vegetable membranes; he found that these membranes presented an insuperable barrier to the passage of some molecules, while others passed easily through. he thus arrived at a division of matter into colloidal and crystalloidal. he showed what important applications of this division might be made in practical chemistry, he discussed some of the bearings of this division on the general theory of the molecular constitution of matter, and thus he opened the way which leads into a new territory rich in promise to him who is able to follow the footsteps of its discoverer. other investigators have followed on the general lines laid down by graham; connections, more or less precise, have been established between chemical and physical properties of various groups of compounds. it has been shown that the boiling points, melting points, expansibilities by heat, amounts of heat evolved during combustion, in some cases tinctorial powers of dye-stuffs, and other physical constants of groups of compounds, vary with variations in the nature, number and arrangements of the atoms in the molecules of these compounds. but although much good work has been done in this direction, our ignorance far exceeds our knowledge regarding the phenomena which lie on the borderlands between chemistry and physics. it is probably here that chemists look most for fresh discoveries of importance. as each branch of natural science becomes more subdivided, and as the quantity of facts to be stored in the mind becomes daily more crushing, the student finds an ever-increasing difficulty in passing beyond the range of his own subject, and in gaining a broad view of the relative importance of the facts and the theories which to him appear so essential. in the days when the foundation of chemistry was laid by black, priestley, lavoisier and dalton, and when the walls began to be raised by berzelius and davy, it was possible for one man to hold in his mental grasp the whole range of subjects which he studied. even when liebig and dumas built the fabric of organic chemistry the mass of facts to be considered was not so overpowering as it is now. but we have in great measure ourselves to blame; we have of late years too much fulfilled liebig's words, when he said, that for rearing the structure of organic chemistry masters were no longer required--workmen would suffice. and i think we have sometimes fallen into another error also. most of the builders of our science--notably lavoisier and davy, liebig and dumas--were men of wide general culture. chemistry was for them a branch of natural science; of late years it has too much tended to degenerate into a handicraft. these men had lofty aims; they recognized--davy perhaps more than any--the nobility of their calling. the laboratory was to them not merely a place where curious mixtures were made and strange substances obtained, or where elegant apparatus was exhibited and carefully prepared specimens were treasured; it was rather the entrance into the temple of nature, the place where day by day they sought for truth, where, amid much that was unpleasant and much that was necessary mechanical detail, glimpses were sometimes given them of the order, harmony and law which reign throughout the material universe. it was a place where, stopping in the work which to the outsider appeared so dull and even so trivial, they sometimes, listening with attentive ear, might catch the boom of the "mighty waters rolling evermore," and so might return refreshed to work again. chemistry was more poetical, more imaginative then than now; but without imagination no great work has been accomplished in science. when a student of science forgets that the particular branch of natural knowledge which he cultivates is part of a living and growing organism, and attempts to study it merely as a collection of facts, he has already esau-like sold his birthright for a mess of pottage; for is it not the privilege of the scientific student of nature always to work in the presence of "something which he can never know to the full, but which he is always going on to know"--to be ever encompassed about by the greatness of the subject which he seeks to know? does he not recognize that, although some of the greatest minds have made this study the object of their lives, the sum of what is known is yet but as a drop in the ocean? and has he not also been taught that every honest effort made to extend the boundaries of natural knowledge must advance that knowledge a little way? it is not easy to remember the greatness of the issues which depend on scientific work, when that work is carried on, as it too often is, solely with the desire to gain a formal and definite answer to some question of petty detail. "that low man seeks a little thing to do, sees it and does it: this high man, with a great thing to pursue, dies ere he knows it. "that low man goes on adding one to one, his hundred's soon hit: this high man, aiming at a million, misses a unit." index. a acids, connected by lavoisier with oxygen, ; boyle's and other early definitions, ; opposed in early medicine to alkalis, ; grouped, ; salts, ; "the primordial acid," ; oxygen not a necessary constituent, ; new division of acids by davy, ; acids of different basicity, ; modern conception of acids, . affinity, chemical, apparently suspended by electricity, ; history of term "affinity," ; tables of, ; dependent on electric states, . air, composition of, determined by cavendish, ; dalton's investigations, . alchemy, ; alchemical symbols of metals, ; quotations from alchemists, , ; alchemical poetry, . alcoates, . alkalis, ; fixed and volatile, ; mild and caustic, examined by black, ; connection with earths, ; name of "base" given by rouelle, ; gay-lussac's alkalizing principle, . ammonia, discovered by priestley, . atmolysis, . atomic theory, dawn of, ; early views of greek philosophers, ; of epicurus and lucretius, ; of newton and bernoulli, ; dalton's new views--combination in simple multiples, , _et seq._; the theory made known by dr. thomson, ; it is opposed at first by davy, ; dalton's rules for arriving at atomic weights, ; more accurately applied by berzelius, , ; diagrams of atoms, , ; the theory as carried out by gay-lussac and avogadro, , _et seq._; conception of the molecule, ; molecular and atomic weight, ; graham's work on molecular reactions, ; berzelius's dualistic views, ; they are attacked by dumas, ; conception of the compound radicle, ; laurent's unitary theory, ; modern conception of molecule, ; revision of atomic weights, ; equivalency of atoms, . avogadro, his elucidation of the atomic theory, , _et seq._; introduces the idea of molecules, ; law known as avogadro's law, . b base (of salts), ; basic lines in spectrum, . becher, john j., born at speyer, ; his three principles of metals, ; his principle of inflammability, ; his views on acids, . berthollet, analyzes ammonia, ; adheres to the lavoisierian theory of combustion, ; questions doctrine of fixity of composition, ; and necessary presence of oxygen in acids, ; shows variable nature of affinities, . berzelius, johann j., ; determines weights of elementary atoms, ; his birth and education, ; works at stockholm, ; his slight appliances and large discoveries, ; he reviews dalton's atomic theory, ; his views superseded by avogadro's generalization, ; he accepts law of isomorphism, ; and davy's discovery of chlorine, ; his views on affinity of atoms, ; his dual classification, ; works at organic chemistry, ; his dualism attacked by dumas, . black, joseph, born at bordeaux, ; his education, ; his thesis on magnesia and discovery of "fixed air," , _et seq._; inquiries into latent heat, ; professor at edinburgh, ; his death and character, , _et seq._; _resumé_ of his work, ; his examination of alkalis, . boyle, hon. robert, ; his "sceptical chymist," ; law known as "boyle's law," ; opposes doctrine of elementary principles, ; his definition of an acid, ; extends the knowledge of salts, . bromine, discovered by balard, . c carbonic acid gas, or "fixed air," studied by black, ; by priestley, , . cavendish, hon. henry, rediscovers hydrogen, , ; and composition of water and air, . chloral, } produced by liebig, composition determined by dumas, . chloroform,} chlorine, discovered by davy, ; replaces hydrogen in organic compounds, . colloids, . combination in multiple proportions, . combustion, studied by early chemists, (_vide_ "phlogistic theory"); studied by black, ; his views of lavoisier's theory, ; priestley's views of combustion, ; lavoisier's experiments, , _et seq._; liebig's combustion-tube, . compound radicle, ; the idea of substitution, , . conservation of mass, doctrine of, . crystallization, water of, . crystalloids, . d dalton, john, his birth and education, ; "answers to correspondents," ; his meteorological observations, ; teaches at manchester, ; colour-blind, ; pressures of gaseous mixtures, ; strives after general laws, ; first view of atomic theory, ; visits paris, ; honours conferred on him, , ; dies, ; consideration of atomic theory (which see), , _et seq._; his "new system of chemical philosophy," ; fixes atomic weight of hydrogen, ; small use he makes of books, ; inaccurate as an experimenter, ; his method compared with priestley's, . davy, sir humphry, ; opposes the atomic theory, ; accepts same, ; studies the chemical aspects of electricity, ; experiments on the acid and alkali said to be produced by electrolyzing water, ; apparent suspension of chemical affinities by action of electricity, ; discovers potassium, ; and sodium, ; the metallic bases of earths, ; proves the elementary nature of chlorine, ; davy's birth and youth, ; experiments on heat, ; his work at bristol, ; inhales gases, ; lectures at the royal institution, ; discovers iodine and invents safety-lamp, ; dies, . dialysis, . diffusion-rates of gases, ; distinguished from transpiration-rates, ; diffusion-rates of liquids, . dulong, his law of atomic heat, . dumas, jean b. a., birth and education, ; physiological studies, ; meets von humboldt, ; attacks the dualism of berzelius, ; dumas's vapour density process, ; ethers and alcohols, ; chlorine in connection with organic compounds, ; determines composition of chloral and chloroform, ; studies fermentation, ; member of the national assembly, ; takes office, . e earths, ; stahl's views, ; the connection between earths and alkalis, ; their metallic bases, , . economy of waste materials, . electric affinity, , . electricity, volta's battery, ; used to decompose water, ; new metals discovered by its help, . elements: old doctrine of elementary principles opposed by boyle, ; modern definition of element, (_vide_ "spectroscopic analysis"--basic lines, ). equivalency, conception of, . f fermentation, studied by dumas, . fourcroy, calls lavoisier's views "la chimie française,", g gay-lussac, , , , , . gerhardt, , . graham, thomas, early life, ; made master of the mint, ; his death, ; studies alcoates, ; formulates conception of acids of different basicity, ; considers hydrogen a metal, ; investigates phenomena observed by döbereiner, ; diffusion-rates of gases, ; of liquids, ; his atmolyzer, ; his dialyzer, ; studies movements and reactions of molecules, . h hales's experiments on gases, . heat, black's study of latent heat, ; specific heat, ; dalton lectures on, ; law of capacity for heat, ; heat as produced by friction, . helmholtz, ; vortex atoms, . hooke, robert, his "micographia," ; studies combustion, . humboldt, alexander von, assists liebig, ; and dumas, . hydrochloric acid discovered by priestley, ; a stumbling-block to lavoisierian chemists, ; studied by davy, . hydrogen, rediscovered by cavendish, ; experimented on by priestley, ; its atomic weight decided by dalton, ; graham considers it a metal, . i iodine, discovered by davy, . isomerism, . isomorphism, law of, . l laplace, assists lavoisier, . latent heat, black's theory of, . laurent, his unitary theory, , . lavoisier, antoine l., born at paris, ; confutes idea of transmutation, ; paper on calcination of tin, ; meets priestley, , ; his theory of combustion, , ; his chemical nomenclature, ; he is guillotined, ; _resumé_ of his work, ; his views on salts, , . liebig, justus, birth, ; humboldt and gay-lussac, ; his improved combustion-tube, ; studies the cyanates, ; distinction between organic and inorganic chemistry effaced, ; produces chloroform and chloral, ; benzoyl, ; he leaves giessen for munich, ; his practical and economic discoveries, ; death, ; his failure to discover bromine, . lockyer, his work with spectroscope, (and _vide_ "spectroscopic analysis"). m mayow, john, studies combustion, . metals, new, discovered by berzelius, ; by davy, ; hydrogen a metal, . meyer, his views on acids, . mitscherlich's law of isomorphism, . molecule, conception of, ; molecular weight, ; molecular mobility of gases, ; movements and reactions of molecules, ; modern conception of, . morveau, de, embraces lavoisier's views, . muriatic acid (_vide_ "hydrochloric acid,") . n nitric acid, discovered by priestley, ; produced by electrolysis, . nomenclature, lavoisier's system of, . o oil, principle of, . organic chemistry, worked at by berzelius, ; attempts to define it, ; loose application of the term, ; wöhler's manufacture of urea abolishes distinction of organic and inorganic chemistry, . oxygen discovered by priestley, ; lavoisier's experiments, ; it is viewed by him as an acidifier, , ; berthollet shows it not a necessary constituent of acids, (_vide_ "acids"). p paracelsus, ; his pamphlet, "tripus aureus," etc., . petit, . phlogistic theory, ; enunciated by stahl, ; abandoned by black, ; phlogiston described as a kind of motion, ; discovery of dephlogisticated air, ; the theory overthrown by lavoisier, . phosphoric acid, . pneumatic trough, invented by priestley, . potassium, discovered by davy, . prussic acid, discovered by berthollet, . priestley, joseph, born, ; bred for the ministry, ; writes on electricity, ; his pneumatic trough, ; discovers oxygen, ; meets lavoisier, , ; goes to birmingham, ; his experiments on hydrogen, ; his house burnt by rioters, ; emigrates to america, ; dies there, ; _resumé_ of his work, ; his method compared with that of dalton, . q quantitative analysis neglected by early chemists, ; first accurately employed by black, ; used by lavoisier, . r respiration explained by lavoisier, . revolution, french, its effect on priestley, ; lavoisier guillotined, . richter's equivalents of acids and bases, . ripley, canon, an alchemist, his poems, . rouelle, invents term "base," ; his studies on salts, . s salts, ; "principle of salt" opposed by boyle, ; earth or alkali the _base_ of salts, ; rouelle's inquiries, ; lavoisier's definition, ; considered as metallic derivatives of acids, ; alcoholic salts, . "sceptical chymist, the," by hon. robert boyle, - . shelburne, earl of, patron of priestley, ; to whom he grants an annuity, . spectroscopic analysis, ; lines in solar spectrum, ; the solar atmosphere, ; lockyer's mapping of the lines, ; basic lines, ; objections to his hypothesis, . stahl, george ernest, born at anspach, ; enunciates the phlogistic theory, , ; his "primordial acid," ; his essential property of earths, . sulphur dioxide, discovered by priestley, . sulphur salts, discovered by berzelius, . t transmutation, confuted by lavoisier, . transpiration of gases, . types, . v valentine, basil, an alchemist, ; his views on alkalis, . van helmont, . vitriols, . volta's electric pile, . w water, its composition discovered by cavendish, - ; nearly discovered by priestley, ; confirmed by lavoisier, ; decomposed by electricity, . weight of ultimate particles, , ; molecular and atomic, ; revision of atomic weights, . wöhler, his account of visit to berzelius, , , ; studies cyanates with liebig, ; results of his discovery as to urea, . wollaston, supports atomic theory, . printed by william clowes and sons, limited, london and beccles. transcriber's note: this book was published in two volumes, of which this is the second. the first volume was released as project gutenberg ebook # , available at http:www.gutenberg.org/ebooks/ . italic text has been marked with _underscores_. please see the end of this project for further notes. the life of sir humphry davy, bart. ll.d. late president of the royal society, foreign associate of the royal institute of france, &c. &c. &c. by john ayrton paris, m.d. cantab. f.r.s. &c. fellow of the royal college of physicians. in two volumes. vol. ii. london: henry colburn and richard bentley, new burlington street. m dccc xxxi. contents. chapter x. mr. faraday's introduction to sir h. davy.--a renewed correspondence on the subject of the gunpowder manufactory.--davy obtains permission from napoleon to visit the continent.--he embarks in a cartel from plymouth.--is arrested at morlaix.--arrives at paris.--visits the louvre.--his extraordinary conduct upon that occasion.--inspects the colossal elephant, and is introduced to m. alavair, its architect.--the discovery of the dungeons of the bastile.--davy's interesting letter to m. alavair.--he attends a meeting of the institute.--is visited by all the principal savans of paris.--the adventure which befell lady davy in the thuilleries' garden.--anniversary dinner of the philomatic society.--the junior chemists of france invite davy to a splendid entertainment.--how far davy is entitled to be considered the discoverer of the true nature of iodine.--napoleon's unlucky experiment with the voltaic battery.--davy is presented to the empress josephine.--an account of the court ceremony at malmaison.--remarks on the conduct of davy during his visit to paris.--he quits the capital of france, and proceeds by way of lyons, to montpellier.--is assisted in experiments on sea-weed by m. berard.--crosses the alps.--arrives at genoa.--institutes experiments on the torpedo.--visits florence, and accomplishes the combustion of the diamond, by the great lens in the cabinet of natural history.--experiments on iodine.--he examines the colours used by the ancients.--visits all the celebrated philosophers of italy and switzerland, with whom he works in their laboratories.--returns to england chapter xi. collieries of the north of england.--fire-damp.--the dreadful explosion at felling colliery described.--letters from the bishop of bristol to the author.--a society is established at bishop-wearmouth for preventing accidents in coal mines.--various projects for ensuring the miner's safety.--the reverend dr. gray, the present bishop of bristol, addresses a letter to sir h. davy, and invites his attention to the subject.--sir h. davy's reply.--farther correspondence upon the possibility of devising means of security.--sir h. davy proposes four different kinds of lamp for the purpose.--the safe-lamp--the blowing-lamp--the piston-lamp--the charcoal-lamp.--his investigation of the properties of fire-damp leads to the discovery of a new principle of safety.--his views developed in a paper read before the royal society on the th of november .--the first safety-lamp.--safety-tubes superseded by safety-canals.--flame sieves.--wire-gauze lamp.--the phenomenon of slow combustion, and its curious application.--the invention of the safety-lamp claimed by a mr. stephenson.--a deputation of coal-owners wait upon sir h. davy, in order to express to him the thanks of the proprietors for his discovery.--mr. buddle announces to dr. gray (now bishop of bristol) the intention of the coal-trade to present him with a service of plate.--the resolutions are opposed, and the claims of stephenson urged, by mr. w. brandling.--a dinner is given to sir humphry, at which the plate is presented to him.--the president and council of the royal society protest against the claims still urged by mr. stephenson's friends.--mr. buddle's letter in answer to several queries submitted to him by the author.--davy's researches on flame.--he receives from the royal society the rumford medals.--is created a baronet.--some observations on the apathy of the state in rewarding scientific merit.--the geological society of cornwall receives the patronage and support of sir humphry chapter xii. sir humphry davy suggests a chemical method for unrolling the ancient papyri.--he is encouraged by the government to proceed to naples for that purpose.--he embarks at dover.--his experiments on the rhine, the danube, the raab, the save, the ironzo, the po, and the tiber, in order to explain the formation of mists on rivers and lakes.--his arrival and reception at naples.--he visits the excavations at herculaneum.--he concludes that it was overwhelmed by sand and ashes, but had never been exposed to burning matter.--he commences his attempt of unrolling the papyri.--his failure.--he complains of the persons at the head of the department in the museum.--he analyses the waters of the baths of lucca.--his return to england.--death of sir joseph banks.--he is elected president of the royal society.--some remarks on that event.--he visits penzance.--is honoured by a public dinner.--electro-magnetic discoveries of oersted extended by davy.--he examines electrical phenomena in vacuo.--the results of his experiments questioned.--he enquires into the state of the water, and aëriform matter in the cavities of crystals.--the interesting results of his enquiry confirm the views of the plutonists chapter xiii. the liquefaction of chlorine gas first effected by mr. faraday, and witnessed by the author.--sir h. davy continues the investigation.--his paper on the application of liquefiable gases as mechanical agents.--other probable uses of these bodies.--he proposes several methods to prevent the fumes which arise from smelting-furnaces.--importance of the subject.--his letters to mr. vivian.--the government solicit the advice of the royal society on the subject of protecting the copper sheathing of ships from the action of sea-water.--sir h. davy charges himself with this enquiry.--he proposes a plan of protection founded on voltaic principles.--his numerous experiments.--he embarks on board the comet steam-vessel bound to heligoland, in order to try his plan on a vessel in motion.--he arrives at mandal, lands, and fishes in the lakes.--the protectors washed away.--he teaches the inhabitants of christiansand to crimp fish.--he remains a few days at arendal.--a norwegian dinner.--the protectors are examined and weighed.--results of the experiment.--the steam-vessel proceeds up the glommen.--he visits the great waterfall.--passes into sweden.--has an interview with the crown prince of denmark, and afterwards with prince christian at copenhagen.--he visits professor oersted.--he proceeds to bremen to see dr. olbers.--returns to england.--his third paper read before the royal society.--voltaic influence of patches of rust.--a small quantity of fluid sufficient to complete the circuit.--he receives from the royal society the royal medal.--the progress of voltaic discovery reviewed.--the principle is of extensive application.--the author's researches into the cause of the solution of lead in spring water.--an account of the numerous trials of protectors.--failure of the plan.--report of the french on the state of the protected frigate, la constance.--dr. revere's new plan of protection chapter xiv. the failure of the ship protectors a source of great vexation to davy.--his letters to mr. poole.--he becomes unwell.--he publishes his discourses before the royal society.--critical remarks and quotations.--he goes abroad in search of health.--his letter to mr. poole from ravenna.--he resigns the presidency of the royal society.--mr. gilbert elected _pro tempore_.--davy returns to england, and visits his friend mr. poole.--salmonia, or days of fly-fishing.--an analysis of the work, with various extracts to illustrate its character chapter xv. sir h. davy's paper on the phenomena of volcanoes.--his experiments on vesuvius.--theory of volcanic action.--his reception abroad.--anecdotes.--his last letter to mr. poole from rome.--his paper on the electricity of the torpedo.--consolations in travel, or the last days of a philosopher.--analysis of the work.--reflections suggested by its style and composition.--davy and wollaston compared.--his last illness.--arrival at geneva.--his death a general review of the history of chemical science, and of the revolutions produced in its doctrines by the discoveries of sir humphry davy appendix--will of sir humphry davy the life of sir humphry davy, bart. &c. &c. chapter x. mr. faraday's introduction to sir h. davy.--a renewed correspondence on the subject of the gunpowder manufactory.--davy obtains permission from napoleon to visit the continent.--he embarks in a cartel from plymouth.--is arrested at morlaix.--arrives at paris.--visits the louvre.--his extraordinary conduct upon that occasion.--inspects the colossal elephant, and is introduced to m. alavair, its architect.--the discovery of the dungeons of the bastile.--davy's interesting letter to m. alavair.--he attends a meeting of the institute.--is visited by all the principal _savans_ of paris.--the adventure which befell lady davy in the thuilleries' garden.--anniversary dinner of the philomatic society.--the junior chemists of france invite davy to a splendid entertainment.--how far davy is entitled to be considered the discoverer of the true nature of iodine.--napoleon's unlucky experiment with the voltaic battery.--davy is presented to the empress josephine.--an account of the court ceremony at malmaison.--remarks on the conduct of davy during his visit to paris.--he quits the capital of france, and proceeds, by way of lyons, to montpellier.--is assisted in experiments on sea-weed by m. berard.--crosses the alps.--arrives at genoa.--institutes experiments on the torpedo.--visits florence, and accomplishes the combustion of the diamond, by the great lens in the cabinet of natural history.--experiments on iodine.--he examines the colours used by the ancients.--visits all the celebrated philosophers of italy and switzerland, with whom he works in their laboratories.--returns to england. it is said of bergman, that he considered the greatest of his discoveries to have been the discovery of scheele.[ ] amongst the numerous services conferred upon science by sir humphry davy, we must not pass unnoticed that kind and generous patronage which first raised mr. faraday from obscurity, and gave to the chemical world a philosopher capable of pursuing that brilliant path of enquiry which the genius of his master had so successfully explored. [ ] see note at page , vol. i. the circumstances which first led mr. faraday to the study of chemistry, and by which he became connected with the royal institution, were communicated to me, by himself, in the following letter. to j. a. paris, m.d. my dear sir, royal institution, dec. , . you asked me to give you an account of my first introduction to sir h. davy, which i am very happy to do, as i think the circumstances will bear testimony to his goodness of heart. when i was a bookseller's apprentice, i was very fond of experiment, and very averse to trade. it happened that a gentleman, a member of the royal institution, took me to hear some of sir h. davy's last lectures in albemarle street. i took notes, and afterwards wrote them out more fairly in a quarto volume. my desire to escape from trade, which i thought vicious and selfish, and to enter into the service of science, which i imagined made its pursuers amiable and liberal, induced me at last to take the bold and simple step of writing to sir h. davy, expressing my wishes, and a hope that, if an opportunity came in his way, he would favour my views; at the same time i sent the notes i had taken at his lectures. the answer, which makes all the point of my communication, i send you in the original, requesting you to take great care of it, and to let me have it back, for you may imagine how much i value it. you will observe that this took place at the end of the year , and early in he requested to see me, and told me of the situation of assistant in the laboratory of the royal institution, then just vacant. at the same time that he thus gratified my desires as to scientific employment, he still advised me not to give up the prospects i had before me, telling me that science was a harsh mistress; and, in a pecuniary point of view, but poorly rewarding those who devoted themselves to her service. he smiled at my notion of the superior moral feelings of philosophic men, and said he would leave me to the experience of a few years to set me right on that matter. finally, through his good efforts i went to the royal institution early in march of , as assistant in the laboratory; and in october of the same year, went with him abroad as his assistant in experiments and in writing. i returned with him in april , resumed my station in the royal institution, and have, as you know, ever since remained there. i am, dear sir, very truly yours, m. faraday. the following is a note of sir h. davy, alluded to in mr. faraday's letter: to mr. faraday. sir, december , . i am far from displeased with the proof you have given me of your confidence, and which displays great zeal, power of memory, and attention. i am obliged to go out of town, and shall not be settled in town till the end of january: i will then see you at any time you wish. it would gratify me to be of any service to you. i wish it may be in my power. i am, sir, your obedient humble servant, h. davy. i must now recall the reader's attention to the affair of the gunpowder manufactory, to which some allusion has been already made. it is far from my wish to intrude upon the public any account of a private transaction; but the circumstances to which i must refer are already well known, and i believe, moreover, that they have been the subject of misrepresentation. the letters i shall introduce appear to me highly interesting; and by the warmth of feeling with which they repel the bare suspicion of his prostituting science to the acquisition of wealth, to develope a feature in his character too important to be omitted in a memoir of his life. from the following letter, it would appear that davy's alarms, with respect to his responsibilities, were first awakened by a sight of the labels, in which his name was introduced.[ ] [ ] i am here bound to state, from a careful examination of all the original documents, that his name was introduced in the very words which he suggested, and which i have at this moment before me in his own handwriting:--so differently, however, does the same sentence strike the eye in print and in manuscript, that an author frequently does not recognise his own composition. to john george children, esq. my dear children, rokeby, july -- . i am very sorry you did not come to cobham, as the party was very pleasant. your apparatus was magnificent, worthy an imperial institute: there were some swine however for the pearls; at least, there was one,--you cannot suppose i mean any other than----. i have been much disturbed and vexed by enquiries respecting the price of _my_ gunpowder, which from the labels i find is supposed to be _sold_ by me. these labels must be altered, so as to put in a clear point my relations to the manufacture; and it must be understood by the public that i have given my gratuitous assistance and advice only. i have written to mr. burton by post, giving two forms. i shall do you more good if these are adopted than i can now; and i wish them to be adopted speedily, as it may otherwise get abroad that i have nothing to do with the powder, and that my name is used in a manner which does not meet my approbation. in the labels in the windows, it should not be _under my directions_, for this implies that i am a superintendent in the manufactory; but it should be--"ramhurst gunpowder, manufactured by messrs. b. c. and co. in the composition of this powder, the proprietors have been assisted by the advice and assistance of sir h. davy." a fair statement will do the manufacture good. misapprehension will do it much harm. i am now at rokeby; we shall be in a few days at braham castle, lord mackenzie's, near dingwall, where we shall stay for a week. after that we shall go to the marquis of stafford's, dunrobin, near goldspie. i am, my dear children, very truly and affectionately yours, h. davy. to the same. my dear children, edinburgh, july . i wrote to you from rokeby. i expressed my feelings respecting the gunpowder. i have been in extreme harass and anxiety from the idea of the use of my name, without the proper explanation, and i certainly expected that no use would have been made of it without my sanction. i never saw the label for the canister till it came to me upon one of them, and i immediately expressed that i was not satisfied with it. i told mr. burton expressly, that in all cases in which my name was used it must be in my own way. he is now at the head of your firm; but it is to _you_, and not to _him_, that i have given, and shall give my assistance. every feeling of friendship and affection prompts my wishes to be useful to you; i have not the same relations to mr. burton. i am very sorry to give you any trouble on this business, but i am sure you cannot wish me to remain in a state of anxiety; and all the friends with whom i have consulted think it absolutely necessary for my reputation, that, when my name is used, a clear statement should be given of the true nature of the connexion. i think it will be more useful to you, and increase your influence and power in the partnership, if my assistance is stated as given to you, and to you only--in this way: "ramhurst gunpowder, manufactured by messrs. burton, children, and co. after an improved process, founded upon experiments and investigations made by sir h. davy, and communicated by him to mr. j. g. children, under whose immediate superintendence the gunpowder is made." i have fully made up my mind on this matter: and if you approve of the above form, i will state it to be the only one to which i will consent. if the gunpowder is called sir h. davy's powder, it must be stated in all cases where my name is used, that it is so called in honour of my discoveries in chemistry, and because i have given my gratuitous assistance in making the experiments and investigations on which the process is founded. i have resolved to make no profit of any thing connected with science. i devote my life to the public in future, and i must have it clearly understood, that i have no views of profit in any thing i do. i am, my dear children, very affectionately yours, h. davy. in subsequent letters, which it is not necessary to publish, davy dwells upon the necessity of his engagements as a partner being legally cancelled, as he cannot endure the idea of his philosophical repose and usefulness being disturbed by the cares of business, or the trouble of litigation. it is scarcely necessary to add, that all the parties concerned in this transaction most readily and cheerfully met davy's wishes, all erroneous impressions were effaced, and the affair was adjusted amicably and satisfactorily; and he prepared to quit england with a mind relieved from all the fears and anxieties which had so unfortunately oppressed it. * * * * * after the emperor of the french had sternly refused his passport to several of the most illustrious noblemen of england, it was scarcely to be expected that sir h. davy would have been allowed to travel through france, in order to visit the extinct volcanoes in auvergne, and afterwards to examine that which was in a state of activity at naples. no sooner, however, had the discovery of the decomposition of the alkalies and earths, and its probable bearings upon the philosophy of volcanic action, been represented by the imperial institute to napoleon, than, with a liberality worthy of the liberator of dolomieu, and consistent with his well-known patronage of science, he immediately and unconditionally extended the required indulgence. in consequence of this permission, sir humphry and lady davy, the former accompanied by mr. faraday as secretary and chemical assistant, and the latter by her own waiting-maid, quitted london on the th of october , and proceeded to plymouth; at which port they immediately embarked in a cartel for morlaix in brittany. on landing in france, they were instantly arrested by the local authorities of the town, who very reasonably questioned the authenticity of their passports, believing it impossible that a party of english should, under any circumstances, have obtained permission to travel over the continent, at a time when the only english in france were detained as prisoners. they were accordingly compelled to remain during a period of six or seven days at the town of morlaix, until the necessary instructions could be received from paris. as soon, however, as a satisfactory answer was returned, they were set at liberty; and they reached the french capital on the evening of the th of the same month. shortly after his arrival, davy called upon his old friend and associate mr. underwood, who, although one of the _détenus_, had during the whole war enjoyed the indulgence of residing in the capital. the expected arrival of davy had been a subject of conversation with the french _savans_ for more than a month. amongst those who were loudest in his praises, was m. ampère, who had for several years frequently expressed his opinion that davy was the greatest chemist that had ever appeared. whether this flattering circumstance had been communicated to the english philosopher i have no means of ascertaining; but mr. underwood informs me that the very first wish that davy expressed was to be introduced to this gentleman, whom he considered as the only chemist in paris who had duly appreciated the value of his discoveries; an opinion which he afterwards took no care to conceal, and which occasioned amongst the _savans_ much surprise, and some dissatisfaction. m. ampère, at the time of davy's arrival, was spending the summer at a place a few miles from paris, in consequence of which the introduction so much desired was necessarily delayed. on the th he was conducted by mr. underwood to the louvre. the english philosopher walked with a rapid step along the gallery, and, to the great astonishment and mortification of his friend and _cicerone_, did not direct his attention to a single painting; the only exclamation of surprise that escaped him was--"what an extraordinary collection of fine frames!"--on arriving opposite to raphael's picture of the transfiguration, mr. underwood could no longer suppress his surprise, and in a tone of enthusiasm he directed the attention of the philosopher to that most sublime production of art, and the chef d'oeuvre of the collection. davy's reply was as laconic as it was chilling--"indeed, i am glad i have seen it;" and then hurried forward, as if he were desirous of escaping from any critical remarks upon its excellencies. they afterwards descended to view the statues in the lower apartments: here he displayed the same frigid indifference towards the higher works of art. a spectator of the scene might have well imagined that some mighty spell was in operation, by which the order of nature had been reversed:--while the marble glowed with more than human passion, the living man was colder than stone! the apathy, the total want of feeling he betrayed on having his attention directed to the apollo belvidere, the laocoon, and the venus de medicis, was as inexplicable as it was provoking; but an exclamation of the most vivid surprise escaped him at the sight of an antinous, treated in the egyptian style, and sculptured in _alabaster_.[ ]--"gracious powers," said he, "what a beautiful stalactite!" [ ] the celebrated italian antiquary visconti has so denominated it. what a strange--what a discordant anomaly in the construction of the human mind do these anecdotes unfold! we have here presented to us a philosopher, who, with the glowing fancy of a poet, is insensible to the divine beauties of the sister arts! let the metaphysician, if he can, unravel the mystery,--the biographer has only to observe that the muses could never have danced in chorus at his birth. on the following morning, mr. underwood accompanied him to the jardin des plantes, and presented him to the venerable vauquelin, who was the first scientific man he had seen in paris. on their return they inspected the colossal elephant which was intended to form a part of the fountain then erecting on the site of the bastile. davy appeared to be more delighted with this stupendous work than with any object he saw in paris: to its architect, m. alavair, he formed an immediate attachment. it has been observed that, during his residence in this city, his likes and dislikes to particular persons were violent, and that they were, apparently, not directed by any principle, but were the effect of sudden impulse. in the course of removing the foundations, and in digging the canal, the subterranean dungeons of the bastile were discovered; they were eight in number, and were called _les oubliettes_. as they were under the level of the ditch of the fortress, any attempt to escape from them by piercing the wall, must have inevitably drowned the unhappy prisoner together with all those who inhabited the contiguous cells; one of which was discovered with the entrance walled up. upon demolishing this wall there appeared the skeleton of the last wretched person who had been thus entombed. in all these discoveries davy took the warmest interest. upon the construction of the elephant, he wrote a letter to m. alavair, to which i am desirous of directing the attention of my scientific readers. it derives its peculiar interest from the opinion which he at that period entertained upon the subject of the excitement of voltaic action by the contact of different metals. to m. antoine alavair. sir, november . it will give me much pleasure if i can repay your civility to me by offering any hints that may be useful in the execution of the magnificent work constructing under your directions. ten parts of copper to one of tin is an excellent composition for a work upon a great scale, nor do i believe any proportions can be better. there is no fear of any decay in the armatures, if they can be preserved from the contact of moisture; but if exposed to air and moisture, the presence of the bronze will materially assist their decay. wherever the iron is exposed to air, it should, if possible, be covered with a thin layer of bronze. when the iron touches the foundation of _lead_, it should in like manner be covered either by lead or bronze. a contact between metals has no effect of corrosion, unless a voltaic circle is formed with moisture, and then the most oxidable metal corrodes; and iron corrodes rapidly both with lead and bronze. the cement which will probably be found the most durable will be lime, fine sand, and scoria of iron. the materials should be very fine and intimately mixed. the ancients always made their cements for great works some months before they were used. i have the honour to be, sir, with much consideration, your obedient humble servant, h. davy. davy took up his abode at the hotel des princes, rue richelieu; whither the principal _savans_ of paris hastened to pay their respects; which they did with an alacrity and cheerfulness equalled only by the courtesy of manner with which they expressed their congratulations. on the nd of november, davy attended the first class of the institute, and was placed on the right hand of the president, who on taking the chair announced to the meeting that it was honoured by the presence of "le chevalier davy." while davy was at the meeting of the institute, a curious adventure occurred to lady davy, the relation of which, by showing the state of surveillance in which the citizens of paris were held at that period, will enable us to appreciate the extent of the obligation conferred upon sir humphry by the emperor. her ladyship, attended by her maid, had walked into the thuilleries' garden. she wore a very small hat, of a simple cockle-shell form, such as was fashionable at that time in london; while the parisian ladies wore bonnets of most voluminous dimensions. it happened to be a saint's day, on which, the shops being closed, the citizens repaired in crowds to the garden. on seeing the diminutive bonnet of lady davy, the parisians felt little less surprise than did the inhabitants of brobdignag on beholding the hat of gulliver; and a crowd of persons soon assembled around the unknown exotic; in consequence of which, one of the inspectors of the garden immediately presented himself, and informed her ladyship that no cause of '_rassemblement_' could be suffered, and therefore requested her to retire. some officers of the imperial guard, to whom she appealed, replied, that, however much they might regret the circumstance, they were unable to afford her any redress, as the order was peremptory. she then requested that they would conduct her to her carriage; an officer immediately offered his arm, but the crowd had by this time so greatly increased, that it became necessary to send for a corporal's guard; and the party quitted the garden, surrounded by fixed bayonets. november rd, humboldt and gay-lussac paid their first visit of compliment to davy. th.--m. ampère, who came to paris expressly for the occasion, was introduced to davy by mr. underwood, and the two philosophers appeared equally delighted with each other. some years afterwards, however, this feeling of friendly regard, on the part of davy, was turned into one of bitter aversion, in consequence, as it has been supposed, of certain perfidious insinuations, by which some of the _savans_, instigated by feelings of jealousy, had contrived to prejudice his mind; and which even led him to exert all his efforts to oppose the election of ampère as a foreign member of the royal society. after ampère's visit, mr. underwood accompanied sir h. and his lady to the imperial library in the rue richelieu, and afterwards to the cathedral of notre dame, where they inspected the crown and imperial regalia. the splendour of the coronation mantle of napoleon may be imagined, when it is stated that its weight exceeded eighty pounds, and that it was lined with the skins of six thousand ermines. th.--they visited the museum of french monuments, in the rue des petits augustines, which contained the tombs and sculptured ornaments preserved from the churches that were demolished during the revolution. this interesting collection, shortly after the restoration of the bourbons, was dispersed. it is a singular fact, that davy expressed more admiration at this inferior exhibition of art, than he did at that of the greek and roman statues in the museum of the louvre. whether his taste had been vitiated by the inspection of less perfect models in his earlier days, is a question which i shall leave more competent judges to decide. th.--they dined with count rumford at auteuil, who showed his laboratory to davy: this was exactly eight months before the poor brokenhearted count sank into the grave, the victim of domestic torment, and of the persecutions of the french _savans_, instigated by his wife, the widow of the celebrated lavoisier. th.--the anniversary dinner of the philomatic society took place on this day, at a restaurateur's in the rue st. honoré; m. dumeril in the chair. although it was very unusual to invite any stranger upon this occasion, sir h. davy and his english friend were requested to favour the company by their presence. thirty-three members were in attendance, amongst whom were ampère, brogniart, cuvier, chevreuil, dulong, gay-lussac, humboldt, thénard, &c. at this dinner various complimentary toasts were proposed: and first, the royal society of london, for which davy having returned thanks, gave the imperial institute. the linnæan society of london, and the royal society of berlin, were given in succession. but the circumstance which evinced the greatest feeling and delicacy towards their english guest, was the company's declining to drink the health of the emperor. it placed their personal safety even in some jeopardy; and not a little apprehension was afterwards felt as to how far napoleon might resent such a mark of disrespect, for seven-eighths of the members present were placemen. november th.--mr. underwood states that on this day he met humboldt at dinner at davy's hotel; and he adds--"i do not know whether you are aware that sir humphry had a superstitious dislike at seeing a knife and fork placed crosswise on a plate at dinner, or upon any other occasion; but i can assure you that such was the fact; and when it occurred in the company of his intimate friends, he always requested that they might be displaced; whenever this could not be done, he was evidently very uncomfortable."[ ] [ ] i repeat this as i received it: from my own personal knowledge i can neither confirm nor refute it; although i am inclined to believe that davy was tinged with a degree of superstitious feeling, or a certain undefined species of credulity, which shelters itself under the acknowledged inadequacy of human reason to connect causes with effects. at about this period, but i am unable to ascertain the particular day, the junior chemists, with thénard as their leader, gave davy a sumptuous dinner at one of the most celebrated restaurateurs in paris. the following persons formed a committee for that purpose: gay-lussac, thénard, dulong, chevreul, laugier, robiquet, and clement. as it was by the chemists only that this dinner was given, neither arago nor ampère was included; but berthollet, chaptal, and vauquelin were invited. on the morning of the rd of november,[ ] m. ampère called upon davy, and placed in his hands a small portion of a substance which he had received from m. clement; and, although it had been in the possession of the french chemists for more than twelve months, so entirely ignorant were they of its true nature and composition, that it was constantly spoken of amongst themselves as x, the _unknown_ body. [ ] the date of this event is important; and mr. faraday, in referring to his journal, finds it to be correctly stated. how far the suggestions of davy led to the discovery of the chemical nature of this interesting substance, which has been since distinguished by the name of _iodine_, is a question which has given rise to much discussion on the continent. it has been moreover questioned, how far the love of science, and the fervour of emulation, can justify the interference which davy is said to have displayed upon the occasion. he is accused of having unfairly taken the subject out of the hands of those who were engaged in its investigation, and to have anticipated their results. as his biographer, i feel that it is not only due to the character of davy, but essential to the history of science, that these questions should be impartially examined; and i have spared no pains in collecting facts for their elucidation. mr. underwood, who was in the constant habit of associating with the parties concerned in the enquiry, has furnished me with some important particulars, and his testimony is fortified by published documents. the substance under dispute was accidentally discovered by m. courtois, a manufacturer of saltpetre at paris, but kept secret by him for several years; at length, however, he communicated it to m. clement, who made several experiments on it, but without any favourable result. on the rd of august , clement exhibited to mr. underwood the beautiful experiment of raising it into a violet-coloured vapour, and that gentleman assures me that this was the only peculiar property which had at that time been recognised as distinguishing it. a few days previous to this event, m. ampère had received a specimen of the substance, which he had carefully folded up in paper, and deposited in his pocket, but on arriving at home, and opening the packet, he was surprised to find that his treasure had vanished. clement, however, furnished him with another supply, and it was this parcel that ampère transferred into the hands of davy; and "for which," says mr. underwood, "he told me a few days ago, that thénard and gay-lussac were extremely angry with him." the first opinion which the french chemists entertained respecting the nature of iodine, was that it was either a compound of muriatic acid, or of chlorine, since it formed with silver what appeared to be a muriate, or a chloride of that metal; but davy at once observed that the substance so produced blackened too quickly in the sun to justify that opinion. he, however, determined to submit it to a more rigorous examination; and during the latter part of november he worked upon it at his hotel with his own apparatus, and on the rd of december in the laboratory of m. chevreul, at the jardin des plantes, with whom, it may be stated in passing, he perhaps formed a stricter intimacy than with any other chemist during his sojourn in paris. chevreul, however, be it known, was a brother of the angle; and i understand that he still preserves, as sacred trophies, some artificial flies with which davy had supplied him. having pointed out the channel through which iodine first fell into the hands of davy, let us pursue its history. the first public notice of its existence was read by clement at the institute, on the th of november . at the meeting of the th of december, gay-lussac, who had only received some 'x' a few days previous to this date, presented a short note, in which he gave the name of _iode_ to the body, and threw out a hint as to its great analogy to chlorine, while he stated that two hypotheses might be formed as to its nature, that it might be considered as a simple substance, or as a compound of oxygen. on the th of the same month, a letter addressed to m. le chevalier cuvier, and dated december th, was read from davy to the institute, in which he offered a general view of its chemical nature and relations;[ ] and on the th of january , he communicated to the royal society of london, a long and elaborate paper, dated paris, december , , and entitled, "some experiments and observations on a new substance, which becomes a violet-coloured gas by heat." in this paper, while the author assigned to gay-lussac all the credit to which his communication of the th of december may be supposed to entitle him, he evidently felt that some explanation was due to the chemical world for his having pursued the enquiry. "m. gay-lussac," he observes, "is still engaged in experiments on this subject, and from his activity and great sagacity, a complete chemical history of it may be anticipated. but as the mode of procuring the substance is now known to the chemical world in general, and as the combinations and agencies of it offer an extensive field for enquiry, and will probably occupy the attention of many persons; and as the investigation of it is not pursued by the discoverer himself, nor particularly by the gentlemen to whom it was first communicated, i shall not hesitate to lay before the royal society an account of the investigations i have made upon it; and i do this with the less scruple, as my particular manner of viewing the phenomena has led me to some new results, which probably will not be considered by the society as without interest in their relation to the general theory of chemistry, and in their possible application to some of the useful arts." [ ] see _annales de chimie_, tome , p. . it appears from mr. faraday's journal, that he worked upon iodine with a borrowed voltaic pile, at his hotel, on the morning of the th; and the results of his experiments are described at the conclusion of the above letter. it was not until august , that gay-lussac read his paper on the subject, which was subsequently published in the _annales de chimie_. after the above short, but i trust honest statement, can any reasonable doubt exist, that, if davy had not visited paris, iodine would have remained at the end of the year , as it had been for two preceding years--the unknown x? in a communication published in the first volume of the royal institution journal, davy offers the following observations upon this subject: "with regard to iodine, the first i had of it was from m. ampère, who, before i had seen the substance, supposed that it might contain a new supporter of combustion. "who had most share in developing the chemical history of that body, must be determined by a review of the papers that have been published upon it, and by an examination of their respective dates. when m. clement showed iodine to me, he believed that the hydriodic acid was muriatic acid; and m. gay-lussac, after his early experiments, made originally with m. clement, formed the same opinion, and _maintained_ it, when i _first_ stated to him my belief that it was a new and peculiar acid, and that iodine was a substance analogous in its chemical relations to chlorine." i was very desirous of ascertaining the feeling which at present prevails amongst the french chemists upon this subject; and i therefore requested mr. underwood to make such enquiries as might elicit the required information. in a letter from that gentleman, dated "paris, august , ," he says, "though thénard and gay-lussac retain great bitterness of feeling towards davy, on account of the affair of iodine, chevreul and ampère are still, as they ever were, of opinion, that such a feeling has its origin in a misconception; that what davy did, was from the honest desire of promoting science, and not from any wish to detract from the merit of the french chemists." during his visit to paris, davy was not introduced to the emperor. lady davy observed to me, that, although sir humphry felt justly grateful for the indulgence granted to him as a philosopher, he never, for a moment, forgot the duty he owed his country as a patriot; and that he objected to attend the levee of her bitterest enemy. on the other hand, it is said that napoleon never expressed any wish to receive the english chemist; and those who seek in the depths for that which floats upon the surface, have racked their imaginations in order to discover the source of this mysterious indifference; but i apprehend that we have only to revert to the political state of europe in the year , and the problem will be solved. amongst the reasons for supposing that the emperor must have felt ill disposed towards the english philosopher, the following story has been told; which, as an anecdote, is sufficiently amusing; and i can state upon the highest authority, that it is moreover perfectly true. it is well known that bonaparte, during his whole career, was in the habit of personal intercourse with the _savans_ of paris, and that he not unfrequently attended the sittings of the institute. upon being informed of the decomposition of the alkalies, he asked, with some impetuosity, how it happened that the discovery had not been made in france?--"we have never constructed a voltaic battery of sufficient power," was the answer. "then," exclaimed bonaparte, "let one be instantly formed, without any regard to cost or labour." the command of the emperor was of course obeyed; and, on being informed that it was in full action, he repaired to the laboratory to witness its powers; on his alluding to the taste produced by the contact of two metals, with that rapidity which characterised all his motions, and before the attendants could interpose any precaution, he thrust the extreme wires of the battery under his tongue, and received a shock which nearly deprived him of sensation. after recovering from its effects, he quitted the laboratory without making any remark, and was never afterwards heard to refer to the subject. it is only an act of justice to state that davy, during his residence in the french capital, so far from truckling to french politics, never lost an opportunity of vindicating with temper the cause of his own country. at the théâtre de la porte saint martin, a melodrame was got up, with the avowed intention of exposing the english character to the execration of the audience. lord cornwallis was represented as the merciless assassin of the children of tippoo saib. davy was highly incensed at the injustice of the representation, and abruptly quitted the theatre in a state of great indignation. whatever objections might have existed in his mind, as to his attending a levee of the emperor, they did not operate in preventing his being presented to the empress at malmaison; but he could not be prevailed upon to appear upon that occasion, in any other than a morning dress; and it was not until after repeated entreaty, and the assurance that he would not be admitted into the _salle de reception_, that he consented to exchange a pair of half-boots that laced in front, and came over the lower part of his pantaloons, for black silk stockings and shoes. his constant answer to the remonstrances of his friends was, "i shall go in the same dress to malmaison as that in which i called upon the prince regent at carlton house." the introduction of sir humphry and lady davy to the empress josephine, took place at malmaison on the th of november. the only english present were, the earl of beverley, a _détenue_; general sir edward paget, a prisoner of war, taken in spain, and mr. underwood; and it was the first levee at which any of our countrymen had been introduced, with the exception of mr. underwood, who had been frequently in the habit of paying his court to the empress, and to whom, indeed, he was indebted for those indulgences which have been already mentioned. the persons present having arranged themselves in a semicircle, the empress entered the _salle de reception_, and in her usual gracious manner addressed each individual. after this court ceremony, her majesty retired, having previously signified to a select few, her desire that they should follow her into the private apartment. in the boudoir, the conversation became general, and turned upon certain works of art; and upon lady davy expressing, in very florid terms, her admiration of some beautifully embellished cups of porcelain, which were stationed on the mantelpiece, her majesty, with that good-nature which ever distinguished her, immediately presented her with a specimen. the empress then proposed that lady davy should on this occasion visit her conservatories, upon which it is well known she had lavished large sums, and was ambitious to be thought to possess all that was rare and curious. lady davy having expressed some apprehensions as to the coldness of the day, and appearing to be but thinly clad, one of the dames du palais was commanded to provide cloaks; and in a short time, mr. underwood says, a _mountain_ of the most costly and magnificent furs, that probably ever appeared even in a regal palace, were displayed before her; the splendid trophies, we may conclude, of the royal conciliation at tilsit. it was on the th of december , that davy was elected a corresponding member of the first class of the imperial institute; there were forty-eight members present, and he had forty-seven votes: guyton de morveau being the only person who opposed his election. nothing ever exceeded the liberality and unaffected kindness and attention with which the _savans_ of france had received and caressed the english philosopher. their conduct was the triumph of science over national animosity,--a homage to genius, alike honourable to those who bestowed, and to him who received it; and it would be an act of ingratitude, a violation of historical justice, on the part of the english biographer, did he omit to express the pride and admiration with which every philosopher in his country continues to regard it. it would have been fortunate for the cause of science, and fortunate for the historian, could he have terminated the subject with these remarks; but the biographer has an act of justice to perform, which he must not suffer his friendship to evade, nor his partialities to compromise.[ ] [ ] in offering these observations, the reader may readily suppose it has not been without much pain that i have made this sacrifice of personal feeling to principle. i am, however, bound to observe, that sir humphry's sentiments towards france for the liberal indulgence granted to him were both grateful and kindly; and so strongly does lady davy participate in that feeling, that i perhaps owe it to her to state that neither her ladyship's journals or information have been used upon this occasion. it would be an act of literary dishonesty to assert that sir h. davy returned the kindness of the _savans_ of france, in a manner which the friends of science could have expected and desired. there was a flippancy in his manner, a superciliousness and hauteur in his deportment, which surprised as much as they offended. whatever opinions he might have formed as to the talents of the leading chemists, it was weakness to betray, and arrogance to avow them. he had, by a single blow, fatally mutilated the system which was the pride and glory of their nation: it was ungenerous to remind them of his triumph. it required but little tact to have reconciled the french philosophers to the revolution he had effected; but, unfortunately, that cannot be said of davy, which was so wittily observed of voltaire,--that if he trod upon the toes of their prejudices, he touched his hat at the same time: even the affair of iodine, had it been skilfully managed, would never have left an angry feeling. it was not his success, but the manner in which he spoke of it, that rendered it so offensive. he should have acted according to the judicious advice given to a member of the clerical profession, upon his consulting a friend as to the propriety of continuing his field-sports, should he become a dignitary of the church--"you may hunt, but you must not holla." it may be supposed that the unguarded conduct of davy reached the ear of the emperor; for in a conversation with one of the leading members of the institute, napoleon took occasion to observe, that he understood the young english chemist held them all in low estimation. having thus candidly avowed the errors of davy, i may be justified in claiming from the reader his confidence in the sincerity with which i shall attempt to palliate them. from my personal knowledge of his character, i am inclined to refer much of that unfortunate manner, which has been considered as the expression of a haughty consciousness of superiority, to the desire of concealing a _mauvaise honte_ and _gaucherie_--an ungraceful timidity, which he could never conquer. the bashful man, if he possess strong passions, will frequently force himself into a state of effrontery, by a violence of effort which passes amongst ordinary observers for the sallies of pride, or the ebullitions of temper; whereas if, on the contrary, his temperament be cold and passionless, he will exhibit traits of the most painful reserve. this proposition cannot, perhaps, be more forcibly illustrated than by a comparison of the manners of davy and cavendish, whose temperaments were certainly as much opposed to each other as fire is to ice: the latter, however, was shy and bashful, to a degree bordering upon disease; and nothing so much distressed him as an introduction to strangers, or as his being pointed out as a person distinguished in science. on one of the sunday evening _soirées_ of sir joseph banks, he happened to be conversing with his friend mr. hatchett, when dr. ingenhouz, who was rather remarkable for pomposity of manner, approached him with an austrian gentleman in his hand, and introduced him formally to mr. cavendish. he recounted the titles and qualifications of his foreign friend at great length, and concluded by saying, that he had been particularly anxious to be introduced to a philosopher so universally celebrated throughout europe as mr. cavendish. as soon as dr. ingenhouz had finished, the austrian gentleman began; he assured mr. cavendish that one of his principal inducements in coming to london, was to see and converse with one whom he considered the most distinguished chemist of the age. to all these high-flown addresses, mr. cavendish answered not a single word, but stood with his eyes cast down upon the floor, in a state of the most painful confusion. at length, espying an opening in the crowd, he darted through it with all the speed he could command, and never stopped until he reached his carriage, which immediately drove him home. from the same cause, probably, arose davy's inattention and carelessness in those little observances of etiquette, which many may treat as empty and unmeaning ceremonials, but which the members of a polished community regard as the delicate expressions of feeling, and the language of sentiment. it is said, that on conversing in the chamber of the institute, he received one of its most distinguished and venerable members, who approached him with the air of salutation, without rising from his seat; a circumstance perhaps in itself of very trifling importance, but it was considered as a mark of disrespect, which is not readily forgiven, when a spirit of rivalry may be supposed to sharpen the affront. it will be remembered that cæsar might date his loss of popularity to the fact of his having received the senate while sitting in the porch of the temple of venus, and that it formed one of the chief pretences of those who organised the conspiracy against his person. there were, besides, other sources of unpopularity, which we are bound in fairness and candour to impute to the excellencies, rather than to the defects, of his character. if we believe with johnson, that men have sometimes gained reputation from their foibles, we may certainly admit the converse of the proposition, that they have occasionally lost it from their virtues. davy, as we have seen, possessed from his earliest years a frankness of disposition which endeared him to all his friends, but in after life it unquestionably exposed him to various annoyances, which by a little reserve he would have certainly escaped. it is quite surprising how much a little mystery, judiciously managed, will achieve. seven veils converted the fragment of a tile, ploughed up in the neighbourhood of florence, into an object of awful devotion.[ ] [ ] gray's letters. although it must be admitted that our philosopher lost some popularity during his visit to the french metropolis, the _savans_ did not the less respect his talents, or admire his discoveries. they appear to have been impressed with the same sentiment as that which animated voltaire, when he asked whether the discovery of racine's weakness made the part of phædra less admirable. m. dumas, who is certainly by no means distinguished for the readiness with which he is disposed to pay homage to british talent, has declared that davy was the greatest chemical genius that ever appeared. in fact, the more the researches of this great experimentalist are studied, the more they must be admired: every attempt to depreciate their intrinsic importance will only serve to display their exalted merits; every attempt to falsify their results will only tend to demonstrate their accuracy. it is by an elaborate examination only, that the full evidence of their truth can be displayed; there are points which the keen eye of genius will discern, that are invisible to a grosser sense: the coldness of criticism then will only make them glow the brighter; like his own potassium, the contact even of ice, so far from extinguishing, will light them up in splendour. sir humphry left paris on the morning of the th of december, and proceeded by the way of lyons to montpellier, where he remained for a month, and became acquainted with m. berard, who afterwards filled the chemical chair in that university, and in whose laboratory he worked upon the subject of iodine, and examined many of the marine productions of the mediterranean, with the view of determining whether they contained that body. m. berard directed a considerable quantity of the species of _ulva_, which abounds on the coast of languedoc, to be burnt for him; and although the ashes consisted for the most part of common salt, he obtained traces of iodine in the lixivium. from the general results of his experiments, however, he concludes, that the ashes of the _fuci_ and _ulvæ_ of the mediterranean afford it in much smaller quantities than the sea-weed, from which soda is procured; and it was only in a very few instances that he could derive any evidence of its existence. in the ashes of the corallines and sponges, he could not obtain the slightest indication of its presence. during this period he also extended his enquiries respecting the chemical agencies of iodine, and the properties of several of its compounds, especially of those in which he believed it to exist in triple combination with alkalies and oxygen, and for which he proposed the name of _oxy-iodes_.[ ] [ ] these are the _iodates_ of the present day; but davy, it would seem, resisted the conviction of iodic acid being an _oxy-acid_, upon the same grounds that he opposed the views of m. gay-lussac with regard to the nature of chloric acid. while at montpellier, davy witnessed the procession of the pope on his return to rome. his holiness appeared in a state of great humiliation, and, on being supplicated by a poor woman to cure her child, he replied, that she must propitiate heaven by her prayers, for that he was himself a mere mortal, without power to heal or to save. he quitted montpellier on the th of february, and, accompanied by m. berard, visited the fountain of vaucluse; he afterwards continued his route to nice, crossed the col de tende, to turin, and arrived at genoa on the th of february; from which place the following letter is dated. to mr. underwood. my dear underwood, genoa, march . i have not received the letter you announced to me in the street, concerning ampère's note, nor any others since i left paris. the note came to me through the prefect of nice, with an indorsement by m. degerand. i crossed the alps by the col de tende, stayed at turin three days, and came here through snow and ice, over the bochetta, where i have been waiting for a fair wind for tuscany. we have had no impediments except from the snow and the east winds. if you can hear any thing of the destination of the letters i have twice missed, i shall thank you to let me know by addressing me at rome at the _posta_. i shall be most happy to hear some news of you here, and shall always feel a lively interest in your plans, and in your welfare. i have been making some experiments here on the torpedo, but without any decisive results; the coldness of the weather renders the powers of the animal feeble; i hope, however, to resume them at naples. tell m. ampère, i hope he will not give up the subject of the laws of the combination of gaseous bodies, which is so worthy of being illustrated by his talents, and which offers such ample scope for his mathematical powers, united as they are with chemical knowledge:--tell him also that i hope he will sometimes write to me, and that i shall always remember with pleasure the hours i have passed in his society. pray tell me that you are well; and remember me to all that are interested in me. my wife desires her kind remembrances. i am, my dear underwood, your very sincere friend, h. davy. besides researches on the torpedo, davy made farther experiments on the ashes of sea-weed, which were collected for him by professor viviani, of genoa. he left genoa by water on the th, and arrived at florence on the th of march. here he worked in the laboratory of the academia del cimento, on iodine; but more particularly on the combustion of the diamond. the experiments on this latter body were performed by means of the great lens in the cabinet of natural history; the same instrument as that employed in the first trials on the action of the solar heat on the diamond, instituted by cosmo iii. grand duke of tuscany: upon this occasion, he was assisted by count bardi, the director, and signior gazzari, the professor of chemistry at the florentine museum. i have been informed that the hasty, and apparently careless manner in which he conducted his experiments, and which has been already noticed[ ] as being characteristic of his style of manipulation, greatly astonished the philosophers of florence, and even excited their alarm for the safety of the lens, which on all occasions had been used by them with such fastidious caution and delicacy. [ ] vol. i. p. . in the very first trials on the combustion of the diamond, he ascertained a very curious circumstance that had not been before noticed; namely, that the diamond, when strongly ignited by the lens in a thin capsule of platinum, perforated with many orifices, so as to admit a free circulation of air, will continue to burn in oxygen gas after being withdrawn from the focus. the knowledge of this circumstance enabled him to adopt a very simple apparatus and mode of operation in his researches, and to complete in a few minutes experiments which had been supposed to require the presence of a bright sunshine for many hours. the new facts obtained by the experiments on iodine, which he had commenced at montpellier and carried on at florence, he embodied in a memoir, which was read before the royal society on the th of june . it treated more particularly of the triple compounds containing iodine and oxygen,--of the hydrionic acid, and of the compounds procured by means of it,--of the combinations of iodine and chlorine,--of the action of some compound gases on iodine,[ ]--and, lastly, of the mode of detecting iodine in combinations. "if iodine," he says, "exists in sea water, which there is every reason to believe must be the case, though in extremely minute quantities, it is probably in triple union with oxygen and sodium, and in this case it must separate with the first crystals of common salt." [ ] the compounds which he supposed to be thus produced are of a very questionable nature; with respect to that formed with the olefiant gas, he was evidently in error. he quitted florence on the rd, and having visited sienna, entered rome on the th of april. the continent having now become accessible, he met with many of his english friends: but neither the extended society by which he was surrounded, nor the classical attractions of the city of the cæsars, allured him from the pursuits of science. we find that, shortly after his arrival, he renewed his researches on the combustion of different kinds of charcoal, in the laboratory of the academia del lyncei, in which he was assisted by sig. morrichini and barlocci, professors of the college sapienza at rome. having arranged the results of this investigation, together with those relating to the combustion of the diamond, which he had previously obtained at florence, he transmitted a paper to the royal society, entitled "some experiments on the combustion of the diamond, and other carbonaceous substances;" which was read on the rd of june, and published in the second part of the philosophical transactions for the year . no sooner had it been established by various accurate experiments, that the diamond and common charcoal consumed nearly the same quantity of oxygen in combustion, and produced a gas having the same obvious qualities, than various conjectures were formed to explain the remarkable differences in the sensible qualities of these bodies, by supposing some minute difference in their chemical composition. mm. biot and arrago, from the high refractive power of the diamond, suspected that it might contain hydrogen. guyton morveau inferred from his experiments that it was pure carbon, and that charcoal was an oxide of carbon; whereas davy was inclined to believe, from the circumstance of the non-conducting power of the diamond, as well as from the action of potassium upon it, that a minute portion of oxygen might enter its composition, although such a supposition would be at variance with the doctrine of definite proportions; but more lately, in his account of some new experiments on the fluoric compounds, he hazarded the idea that it might be the carbonaceous principle combined with some new and subtile element, belonging to the same class as oxygen, chlorine, and fluorine, which has hitherto escaped detection, but which may be expelled, or newly combined, during its combustion in oxygen. "that some chemical difference," says davy, "must exist between the hardest and most beautiful of the gems and charcoal, between a nonconductor and a conductor of electricity, it is scarcely possible, notwithstanding the elaborate experiments that have been made on the subject, to doubt: and it seems reasonable to expect, that a very refined or perfect chemistry will confirm the analogies of nature, and show that bodies cannot be exactly the same in composition or chemical nature, and yet totally different in all their physical properties." with these impressions, we may readily imagine the ardour with which he availed himself of the use of the great lens at florence. he had in various ways frequently attempted to fuse charcoal,[ ] but without success. in a letter addressed to mr. children is the following passage: "the great result to be hoped for is the fusion of carbon; and then you may use diamond in the manufacture of gunpowder." [ ] the supposed fusion of charcoal by professor silliman, by means of dr. hare's galvanic deflagrator, was a fallacy arising from the earthy impurities of the substance. see _american journal of science_, vol. v. p. , and . he tells us that he had long felt a desire to make some new experiments on the combustion of the diamond and other carbonaceous substances; and that this desire was increased by the new fact ascertained with respect to iodine, which by uniting to hydrogen, affords an acid so analogous to muriatic acid, that it was for some time confounded with that body. his object in these new experiments, was to examine minutely whether any peculiar matter was separated from the diamond during its combustion, and to determine whether the gas, formed in this process, was precisely the same in its minute chemical nature, as that formed in the combustion of common charcoal. by his experiments at florence, he satisfactorily accomplished his wishes, and established beyond a question the important fact, that "the diamond affords no other substance by its combustion than pure carbonic acid gas; and that the process is merely a solution of diamond in oxygen, without any change in the volume of the gas." as one of the principal objects in these researches was to ascertain whether water was formed during the combustion of the diamond, with a view to decide the question of the presence of hydrogen, every possible source of fallacy was excluded. in one experiment there was an evident deposition of moisture, but it was immediately discovered to have been owing to the production of vapour from a cork connected with a part of the apparatus, during the combustion. in the progress of this research, he ascertained a fact, the knowledge of which must not only be considered as important to the present enquiry, but as highly valuable in excluding error from our reasonings upon the delicate results of analysis[ ]--i allude to the extremely minute quantity of water which becomes perceptible by deposition on a polished glass surface. he introduced a piece of paper weighing a grain into a tube of about the capacity of four cubical inches, the exterior of which was gently heated by a candle; immediately a slight but perceptible dew appeared in the interior of the upper part of the tube; the paper taken out and directly weighed in a balance, sensible to - th of a grain, had not suffered any appreciable diminution. if, then, on burning · grains of diamond in oxygen gas, not even a barely perceptible dew was produced, we may consider it as fully proved that this gem cannot contain hydrogen in its composition: but to render the demonstration, if possible, still more complete, he kept a small diamond, weighing · of a grain, in a state of intense ignition by the great lens of the florentine museum, for more than half an hour, in chlorine; but the gas suffered no change, and the diamond underwent no alteration either in weight or appearance: now had the smallest portion of hydrogen been developed, white fumes of muriatic acid would have been visible, and a certain condensation of the gas must have taken place. [ ] it has a more especial bearing upon that experimental research by which the nature of chlorine was established, as described at page , vol. i. to which i beg to refer the chemical reader. the general tenor of his results was equally opposed to the idea of the diamond containing oxygen; for, in such a case, the quantity of carbonic acid generated by the combustion, would, on comparison, have indicated that fact. by combining the carbonic acid with lime, and then recovering the gas from the precipitate by muriatic acid, he found its proportion to be exactly that which was furnished by an equal weight of carrara marble similarly treated. the enquiry next proceeds to the examination of other forms of carbonaceous matter, such as plumbago, charcoal formed by the action of sulphuric acid on oil of turpentine, and that produced during the formation of sulphuric ether; and lastly, the common charcoal of oak. in all these bodies, he detected the presence of hydrogen, both by the water generated during their combustion, and by the production of muriatic acid, when ignited in chlorine. the chemical difference then between the diamond and the purest charcoal, would appear to consist in the latter containing hydrogen; but davy very justly asks whether a quantity of an element, less in some cases than - th part of the weight of the substance, can occasion so great a difference in physical and chemical characters? "it is certainly possible," says he, "yet it is contrary to analogy, and i am more inclined to adopt the opinion of mr. tennant, that the difference depends upon crystallization." in support of such an opinion, he farther adduces the fact, that charcoal after being intensely ignited in chlorine, is not altered in its conducting power or colour: in which case the carbon is freed from the hydrogen, and yet undergoes no alteration in its physical properties. one distinction supposed to exist between the diamond and common carbonaceous substance, the researches of davy have certainly removed, viz. its relative inflammability; for he has shown that the former will burn in oxygen with as much facility as plumbago. the experiments, then, which davy conducted at florence and rome, have removed several important errors with regard to the nature of carbonaceous substances; and though they may not encourage the labours of those speculative chemists who still hope to illustrate the old proverb,[ ] by manufacturing diamonds out of charcoal, they certainty show that they are less chimerical than those of the wild visionaries who sought to convert the baser metals into gold. [ ] "carbonem pro thesauro." while at rome, davy was engaged for several successive days in the house of morrichini, for the purpose of repeating with that philosopher his curious experiments on _magnetisation_. mr. faraday was charged with the performance of the experiments, but never could obtain any results. on the th of may he entered naples, and remained there for three weeks, during which period he visited mount vesuvius, and the volcanic country surrounding it. he describes the crater, at this time, as presenting the appearance of an immense funnel, closed at the bottom, with many small apertures emitting steam; while on the side towards torre del greco, there was a large aperture from which flame issued to a height of at least sixty yards, producing a most violent hissing noise. he was unable to approach sufficiently near the flame to ascertain the results of the combustion; but a considerable quantity of steam ascended from it; and he says, that when the wind blew the vapours upon him, there was a distinct smell both of sulphurous and muriatic acids, but there was no indication of carbonaceous matter from the colour of the smoke; nor was any deposited upon the yellow and white saline matter which surrounded the crater, and which he found to be principally sulphate and muriate of soda, and in some specimens there was also a considerable quantity of muriate of iron. at this period, when the volcano was comparatively tranquil, he observed the solfaterra to be in a very active state, throwing up large quantities of steam, and some sulphuretted hydrogen. at several subsequent periods he revisited vesuvius; and i shall hereafter take occasion to relate all the principal observations he made, and the conclusions at which he arrived, with respect to this the most interesting of all the phenomena of mineral nature. he also took great interest in the excavations at that time going on at pompeii, under the direction of murat, then king of naples, who placed at his disposal several specimens of art, which davy received with a view to investigate the chemical composition of the colours used by the ancients. on the th of may he returned to rome, and again quitted it on the nd of june. i regret to say that the information i have received, as to the future continental travels of our philosopher, is extremely meagre, and will consist of little more than names and dates. of this, however, the reader may be assured, that nothing which relates to his scientific researches has been omitted. from rome he proceeded to terni, and thence to bologna, where he remained for three days; then to mantua, verona, and milan. whether at this or at some subsequent period he went to pavia, in order to pay his homage to the illustrious volta, i entertain some doubt; but the time is immaterial to the point of the anecdote i am about to relate. davy had sent a letter to pavia to announce his intended visit; and on the appointed day and hour, volta, in full dress, anxiously awaited his arrival. on the entrance of the great english philosopher into the apartment, not only in _déshabille_, but in a dress of which an english artisan would have been ashamed, volta started back in astonishment, and such was the effect of his surprise, that he was for some time unable to address him. from milan, which he left on the nd of june, he went to como, domo d'ossola, and then over the simplon, to geneva, where he arrived on the th of that month, and remained until the th of september. during this visit he made various experiments on iodine, at the house of de saussure, which was situated near the edge of the lake, and about three miles from geneva. he also worked at m. pictet's house, on the subject of the heat in the solar spectrum. here also he met with a number of celebrated persons, whose society he greatly enjoyed; amongst whom were madame de stael, benjamin constant, necker, and talma. lausanne, vevay, payerne, berne, zurich, schaffhausen, and munich, were successively visited by him. his route was then continued through tyrol, inspruck, calmar, bolsenna, trent, bassano, vicenza, padua, to venice; where having remained two days, he returned to padua on the th of october, and then proceeded to ferrara, bologna, and pietra-mala; near which latter place, in the apennines, he examined a fire produced by gaseous matter constantly disengaged from a schist stratum, and from the results of its combustion, he concluded it to be pure fire-damp. on again reaching florence, he found that the professors had been dismissed, but he nevertheless resumed his researches, first at home, and afterwards in the laboratory of the grand duke, where he submitted to analysis some gas which had been collected by his attendant mr. faraday, from a cavity in the earth, about a mile from pietra-mala, then filled with water, and which from the quantity of gas disengaged is called _aqua buja_. it was found to be pure light carburetted hydrogen, requiring two volumes of oxygen for its combustion, and producing a volume of carbonic acid gas. "it is very probable," says he, "that these gases were disengaged from coal strata beneath the surface, or from bituminous schist above coal; and at some future period new sources of wealth may be opened to tuscany from this invaluable mineral treasure." on the th he left florence, and passing through levano, tortona, and terni, arrived again at rome, on the nd of november, where he remained till the st of march . during this winter he was engaged in an elaborate enquiry into the composition of ancient colours; and also in experiments upon certain compounds of iodine and of chlorine. upon which subjects he transmitted to the royal society three memoirs, viz. one entitled, "some experiments and observations on the colours used in painting by the ancients," which was read on the rd of february; a second, "on a solid compound of iodine and oxygen," read april ; and a third, "on the action of acids on the salts usually called hyper-oxymuriates, and on the gases produced from them," read may , ; all of which were published in the philosophical transactions for that year. although the paintings of the great masters of greece have been entirely destroyed, either by accident, by time, or by the barbarian conquerors at the period of the decline and fall of the roman empire, yet there is sufficient proof that this art attained a very high degree of excellence amongst a people to whom genius and taste were a kind of birthright, and who possessed a perception, which seemed almost instinctive, of the dignified, the beautiful, and the sublime. our philosopher observes, that the subjects of many of those pictures are described in ancient authors, and that some idea of the manner and style of the greek artists may be gained from the designs on the vases improperly called "etruscan," which were executed by artists of magna græcia, and many of which are probably copies from celebrated works: of their execution and colouring, some faint notion may be gained from the paintings in fresco found at rome, herculaneum, and pompeii; for, although these paintings are not properly grecian, yet at the period when rome was the metropolis of the world, the fine arts were cultivated in that city exclusively by greek artists, or by artists of the greek school; while it is evident, on comparing the descriptions of vitruvius and pliny with those of theophrastus, that the same materials for colouring were employed at rome and at athens. with regard to the nature of these pigments, we may obtain some information from the works of theophrastus, dioscorides, vitruvius, and pliny; but until the present memoir by sir h. davy, no experimental attempt had been made to identify them, or to imitate such of them as are peculiar. his experiments, he informs us, were made upon colours found in the baths of titus, and the ruins called the baths of livia, and in the remains of other palaces and baths of ancient rome, and in the ruins of pompeii. by the kindness of his friend canova, who was charged with the care of the works connected with ancient art in rome, he was enabled to select, with his own hands, specimens of the different pigments that were found in vases discovered in the excavations made beneath the ruins of the palace of titus, and to compare them with the colours fixed on the walls, or detached in fragments of stucco; and signor nelli, the proprietor of the "nozze aldobrandine,"[ ] permitted him to make such experiments upon the colours of that celebrated picture, as was necessary to determine their nature. [ ] the most celebrated picture of antiquity rescued from the ruins of herculaneum. it represents a virgin on her marriage night, with her female attendants. an engraving of it is to be seen in sir william hamilton's work on herculaneum. without entering into the chemical details of the subject, i shall offer a general history of the nature of the colours he examined. of the red colours, he distinguished four distinct kinds, viz.--one bright and approaching to orange, which he found to be _minium_, or the red oxide of lead; a second, dull red, which he ascertained to be an iron ochre; a third, a purplish red, which was likewise an ochre, but of a different tint; and a fourth, a brighter red than the first, which was _vermilion_ or _cinnabar_, a sulphuret of mercury. on examining the fresco paintings in the baths of titus, he found that all the three first colours had been used, the ochres particularly, in the shades of the figures, and the minium in the ornaments on the borders. the fourth red had been employed in various apartments, and formed the basis of the colouring of the niche, and of other parts of the chamber in which the laocoon is said to have been found in the time of raphael; a circumstance which davy considers as being favourable to the belief that such apartments were intended for imperial use, since vermilion, amongst the romans, was a colour held in the highest esteem, and was always one of great costliness. of the yellows, the more inferior were mixtures of ochre and different quantities of chalk; the richer varieties were ochres mixed with the red oxide of lead. the ancients had also two other colours, which were orange, or yellow; the auripigmentum, or [greek: arsenikon], said to approach to gold in the brilliancy of its tint, and which is described by vitruvius as being found native in pontus, and which davy says was evidently sulphuret of arsenic;--and a pale sandarach, said by pliny to have been found in gold and silver mines, and which was imitated at rome by a partial calcination of cerusse. he conceives that this must have been _massicot_, or the yellow oxide of lead mixed with minium; i suspect, however, that davy was mistaken in supposing that the ancients always applied the term sandarach to minium; the [greek: sandarakê] of aristotle was evidently an arsenical sulphuret. in his examination of the ancient frescoes, he could not detect the use of orpiment; but a deep yellow, approaching to orange, which covered a piece of stucco in the ruins near the monument of caius cestius, proved to be oxide of lead, and consisted of massicot and minium. he considers it probable that the ancients used many colours from lead of different tints, between the "_usta_" of pliny, which was our minium, and imperfectly decomposed cerusse, or pale massicot. the differently shaded blues, by the action of acids, uniformly assumed the same tint; from which he concluded that the effect of the base was varied by different proportions of chalk. this base he ascertained to be a _frit_, made by means of soda and sand, and coloured by oxide of copper. the greens were, in general, combinations of copper; and it seemed probable, that although they appeared in the state of carbonate, they might originally have been laid on in that of acetate. the purple of the ancients, the [greek: porphora] of the greeks, and the _ostrum_ of the romans, was regarded as their most beautiful colour, and was obtained from shell-fish. vitruvius states that it was prepared by beating the fish with instruments of iron, freeing the purple liquor from the shell containing it, and then mixing it with a little honey. pliny says that, for the use of the painters, _argentine creta_, (probably a clay used for polishing silver,) was dyed with it, and both vitruvius and pliny state that it was adulterated, or imitations of it made by tinging _creta_ with madder; whence it would appear, that the ancients were acquainted with the art of making a lake colour from that plant, similar to the one used by modern painters. pliny informs us, that the finest purple had a tint like a deep-coloured rose. in the baths of titus, there was found a broken vase of earthenware, which contained a pale rose colour; and davy selected it as an appropriate subject for his analytical experiments. where this colour had been exposed to the action of the air, its tint had faded into a cream colour, but the interior parts retained a lustre approaching to that of carmine. a diluted acid was found to dissolve out of it a considerable quantity of carbonate of lime, with which the colouring principle must have been mixed, as a substance of a bright rose colour remained after the process. this colouring ingredient was proved to contain siliceous, aluminous, and calcareous earths, without any sensible trace of metallic matter, except oxide of iron. upon heating the substance, first in oxygen, and then with hyper-oxymuriate of potash, davy was induced to consider the colouring matter itself as either of vegetable or animal origin; the results, however, were so equivocal, that he renounced the hope of determining its nature from the products of its decomposition. if it be of animal origin, he thinks it is most probably the tyrian or marine purple, as it is likely that the most expensive colour would have been employed in ornamenting the imperial baths. he had not observed any colour of the same tint as this ancient lake in the fresco paintings; the purplish reds in the baths of titus he ascertained to be mixtures of red ochres and the blues of copper. the blacks and browns were mixtures of carbonaceous matter, with the ores of iron or manganese. the black from the baths of titus, as well as that from some ruins near the porta del popolo, deflagrated with nitre, and presented all the character of carbon. this fact agrees with the statements of all the ancient authors who have described the artificial greek and roman black as consisting of carbonaceous matter, either prepared from the powder of charcoal, from the decomposition of resin, (a species of lamp black,) from that of the lees of wine, or from the common soot of wood fires. pliny also mentions the inks of the cuttle-fish, but adds, "_ex his non fit._" davy informs us, that, some years before, he had examined the black matter of the cuttle-fish, and had found it to be a carbonaceous substance mixed with gelatine.[ ] [ ] i find from a note addressed by davy to mr. underwood, that he was engaged in these experiments in october . pliny, moreover, speaks of ivory black invented by apelles; of a natural fossil black; and of a black prepared from an earth of the colour of sulphur. davy is of opinion, that both these latter pigments were ores of iron and manganese; and he observes that the analysis of some purple glass satisfied him that the ancients were well acquainted with the ores of manganese. the _whites_ which he examined from the baths of titus, as well as those from other ruins, were either chalk, or fine aluminous clay; and he states that, amongst all his researches, he never once met with cerusse. this interesting account of the colours used by the ancients is followed by observations on the manner in which they were applied; and the paper is concluded with some general remarks of much practical importance. the azure, he says, of which the excellence is sufficiently proved by its duration for years, may be easily and cheaply imitated: he found, for instance, that fifteen parts of carbonate of soda, twenty parts of opaque flint powdered, and three parts of copper filings, by weight, when strongly heated together for two hours, yielded a compound substance of exactly the same tint, and of nearly the same degree of fusibility; and which, when powdered, produced a fine deep sky-blue. the azure, the red and yellow ochres, and the blacks, appear to have been the only pigments which have not undergone any change in the fresco paintings. the vermilion presents a darker hue than that of recently made dutch cinnabar; and the red lead is inferior in tint to that sold in the shops. the greens are generally dull. the blue frit above mentioned, he considers as a colour composed upon the truest principles; and he thinks there is reason to believe, that it is the colour described by theophrastus as the one manufactured at alexandria. "it embodies," says he, "the colour in a composition like stone, so as to prevent the escape of elastic matter from it, or the decomposing action of the elements upon it." he suggests the possibility of making other _frits_, and thinks it would be worth while to try whether the beautiful purple given by oxide of gold could not be made useful in a deeply tinted glass. where _frit_ cannot be employed, he observes that metallic combinations which are insoluble in water, and which are saturated with oxygen or some acid matter, have been proved by the testimony of seventeen centuries to be the best pigments. in the red ochres, for example, the oxide of iron is fully combined with oxygen and carbonic acid; and the colours composed of them have never changed. the carbonates of copper, which consist of an oxide and an acid, have suffered but little alteration. massicot and orpiment, he considers as those which have been the least permanent amongst all the mineral colours. he next takes a view of the colours which owe their origin to the improvements of modern chemistry. he considers the _patent yellow_ to be more permanent, and the chromate of lead more beautiful, than any yellow possessed by the greeks or romans. he pronounces _scheele's green_ (arsenite of copper), and the insoluble muriatic combinations of copper, to be more unalterable than the ancient greens; and he thinks that the sulphate of baryta offers a white far superior to any pigment possessed by the ancients. in examining the colours used in the celebrated nozze aldobrandine, he recognised all the compounds which his analytical enquiries had established: viz. the reds and yellows were all ochres; the blues, the alexandrian frit; the greens, copper; the purple, especially that in the garment of the pronuba, appeared to be a compound colour of red ochre and copper; the browns and blacks were mixtures of ochres and carbon; while the whites were carbonate of lime. "the great greek painters," he adds, "like the most illustrious artists of the roman and venetian school, were probably sparing in the use of the more florid tints in historical and moral painting, and produced their effects rather by the contrasts of colouring in those parts of the picture where a deep and uniform tint might be used, than by brilliant drapery. "if red and yellow ochres, blacks and whites, were the pigments most employed by protogenes and apelles, so they are likewise the colours most employed by raphael and titian in their best style. the st. john and the venus, in the tribune of the gallery at florence, offer striking examples of pictures in which all the deeper tints are evidently produced by red and yellow ochres, and carbonaceous substances. "as far as colours are concerned, these works are prepared for that immortality which they deserve; but unfortunately, the oil and the canvass are vegetable materials, and liable to decomposition, and the last is even less durable than the wood on which the greek artists painted their celebrated pictures. "it is unfortunate that the materials for receiving those works which are worthy of passing down to posterity as eternal monuments of genius, taste, and industry, are not imperishable marble or stone:[ ] and that _frit_, or unalterable metallic combinations have not been the only pigments employed by great artists; and that their varnishes have not been sought for amongst the transparent compounds[ ] unalterable in the atmosphere." [ ] copper, it is evident from the specimens in the ruins of pompeii, is a very perishable material; but modern science might suggest some voltaic protection. [ ] davy thinks that the artificial hydrat of alumina will probably be found to be a substance of this kind; and that, possibly, the solution of boracic acid in alcohol will form a varnish. he also thinks, that the solution of sulphur in alcohol is worthy of an experiment. in his memoir "on a solid compound of iodine and oxygen," he enumerates, amongst the agencies of that body, its singular property of forming crystalline combinations with all the fluid or solid acids. it will be unnecessary to follow him through this investigation, since its results have been found to be erroneous. m. serullas[ ] has lately shown that the crystalline bodies of davy are nothing more than the iodic acid, which being insoluble in acids, is necessarily precipitated by them. [ ] annales de chimie, t. . p. . his paper "on the action of acids on salts usually called hyper-oxymuriates," announced the important fact of chlorine forming with oxygen a compound, in which the latter element exists in a still greater proportion than in the body previously described by him under the name of _euchlorine_.[ ] [ ] see page . vol. i. before finally quitting italy, he spent three weeks at naples, during which period he experimented on iodine and fluorine in the house of sementini; he also paid several visits to vesuvius, and found the appearances of the crater to be entirely different from those which it presented in the preceding year:[ ] there was, for instance, no aperture in it; it was often quiet for minutes together, and then burst out into explosions with considerable violence, sending fluid lava, and ignited stones and ashes, to a height of many hundred feet in the air. [ ] see page . vol. ii. "these eruptions," says he, "were preceded by subterraneous thunder, which appeared to come from a great distance, and which sometimes lasted for a minute. during the four times that i was upon the crater, in the month of march, i had at last learnt to estimate the violence of the eruption from the nature of the sound: loud and long-continued subterraneous thunder indicated a considerable explosion. before the eruption, the crater appeared perfectly tranquil; and the bottom, apparently without an aperture, was covered with ashes. soon, indistinct rumbling sounds were heard, as if at a great distance; gradually, the sound approached nearer, and was like the noise of artillery fired under our feet. the ashes then began to rise and to be thrown out with smoke from the bottom of the crater; and lastly, the lava and ignited matter was ejected with a most violent explosion. i need not say, that when i was standing on the edge of the crater, witnessing this phenomenon, the wind was blowing strongly from me; without this circumstance, it would have been dangerous to have remained in such a situation; and whenever from the loudness of the thunder the eruption promised to be violent, i always ran as far as possible from the seat of danger. "as soon as the eruption had taken place, the ashes and stones which rolled down the crater seemed to fill up the aperture, so that it appeared as if the ignited and elastic matter were discharged laterally; and the interior of the crater assumed the same appearance as before." on the st of march, he quitted naples, and returned to england by the following route: rome--narni--nocere--fessombone--imola--mantua--(march ,) verona--pero--trente--botzen--brennah--inspruck--zirl--(april ,) reuti-menningen--ulm--(april ,) stutgard--heidelburg--mayence--boppert--coblentz--cologne--(april ,) leuch--brussels--ostend--dover--london, april , . chapter xi. collieries of the north of england.--fire-damp.--the dreadful explosion at felling colliery described.--letters from the bishop of bristol to the author.--a society is established at bishop-wearmouth for preventing accidents in coal mines.--various projects for ensuring the miner's safety.--the reverend dr. gray, the present bishop of bristol, addresses a letter to sir h. davy, and invites his attention to the subject.--sir h. davy's reply.--farther correspondence upon the possibility of devising means of security.--sir h. davy proposes four different kinds of lamp for the purpose.--the safe-lamp--the blowing-lamp--the piston-lamp--the charcoal-lamp.--his investigation of the properties of fire-damp leads to the discovery of a new principle of safety.--his views developed in a paper read before the royal society on the th of november .--the first safety-lamp.--safety-tubes superseded by safety-canals.--flame sieves.--wire-gauze lamp.--the phenomenon of slow combustion, and its curious application.--the invention of the safety-lamp claimed by a mr. stephenson.--a deputation of coal-owners wait upon sir h. davy, in order to express to him the thanks of the proprietors for his discovery.--mr. buddle announces to dr. gray (now bishop of bristol) the intention of the coal trade to present him with a service of plate.--the resolutions are opposed, and the claims of stephenson urged, by mr. w. brandling.--a dinner is given to sir humphry, at which the plate is presented to him.--the president and council of the royal society protest against the claims still urged by mr. stephenson's friends.--mr. buddle's letter in answer to several queries submitted to him by the author.--davy's researches on flame.--he receives from the royal society the rumford medals.--is created a baronet.--some observations on the apathy of the state in rewarding scientific merit.--the geological society of cornwall receives the patronage and support of sir humphry. a few months after the return of sir humphry davy to england, his talents were put in requisition to discover some remedy for an evil which had hitherto defied the skill of the best practical engineers and mechanics of the kingdom, and which continued to scatter misery and death amidst an important and laborious class of our countrymen. to collect and publish a detailed account of the numerous and awful accidents which have occurred within the last few years, from the explosion of inflammable air, or _fire-damp_, in the coal mines of the north of england, would present a picture of the most appalling nature. it appears from a statement by dr. clanny, in the year ,[ ] that, in the space of seven years, upwards of three hundred pitmen had been suddenly deprived of their lives, besides a considerable number who had been severely wounded; and that more than three hundred women and children had been left in a state of the greatest distress and poverty; since which period the mines have increased in depth, and until the happy discovery of davy, the accidents continued to increase in number. [ ] phil. transact. . it may well be asked how it can possibly have happened that, in a country so enlightened by science and so distinguished for humanity, an evil of such fearful magnitude, and of such frequent recurrence, should for so long a period have excited but little sympathy, beyond the immediate scene of the catastrophe. it would seem that a certain degree of doubt and mystery, or novelty, is essentially necessary to create that species of dramatic interest by which the passions are excited through the medium of the imagination: it is thus that the philanthropist penetrates unknown regions, in search of objects for his compassion, while he passes unheeded the miserable groups who crowd his threshold; it is thus that the statesman pleads the injuries of the negro with an eloquence that shakes the thrones of kings, while he bestows not a thought upon the intrepid labourers in his own country, who for a miserable pittance pass their days in the caverns of the earth, to procure for him the means of defying the severity of winter, and of chasing away the gloom of his climate by an artificial sunshine. that the benefits conferred upon mankind by the labours of sir h. davy may be properly appreciated, it is necessary to describe the magnitude of the evil which his genius has removed, as well as the numerous difficulties which opposed his efforts and counteracted his designs. the great coal field,[ ] the scene of those awful accidents which will be hereafter described, extends over a considerable part of the counties of northumberland and durham. the whole surface has been calculated at a hundred and eighty square miles, and the number of different beds of coal has been stated to exceed forty; many of which, however, are insignificant in point of dimensions. the two most important are about six feet in thickness, and are distinguished by the names of _high main_, and _low main_, the former being about sixty fathoms above the latter. [ ] dr. thomson has calculated that the quantity of coal exported yearly from this formation exceeds two millions of chaldrons; and he thinks it may be fairly stated, in round numbers, that, at the present rate of waste, it will continue to supply coal for a thousand years! mr. phillips, however, is inclined to deduct a century or two from this calculation. from this statement, some idea may be formed of the great extent of the excavations, and of the consequent difficulty of successfully ventilating the mines. in some collieries, they are continued for many miles, forming numerous windings and turnings, along which the pitmen have frequently to walk for forty or fifty minutes, before they arrive at the workings; during which time, as well as when at work, they have no direct communication with the surface of the earth. the most ingenious machinery, however, has been contrived for conducting pure air through every part of the mine, and for even ventilating the old excavations, which are technically called _wastes_; and unless some obstruction occur, the plan[ ] so far answers, as to furnish wholesome air to the pitmen, and to diminish, although, for reasons to be hereafter stated, it can never wholly prevent, the dangers of _fire-damp_; the nature of which it will be necessary to consider. [ ] in all large collieries, the air is accelerated through the workings by placing furnaces, sometimes at the bottom, and sometimes at the top of the up-cast shaft; in aid of which, at wall's-end colliery, a powerful air-pump worked by a steam-engine is employed to quicken the draft: this alone draws out of the mines a thousand hogsheads of air every minute. stoppings and trapdoors are also interposed in various parts of the workings, in order to give a direction to the draft. the coal appears to part with a portion of _carburetted hydrogen_, when newly exposed to the atmosphere; a fact which explains the well-known circumstance of the coal being more inflammable when fresh from the pit, than after long exposure to the air. we are informed by the rev. mr. hodgson, that, on pounding some common newcastle coal fresh from the mine, in a cask furnished with a small aperture, he found the gas which issued from it to be inflammable; and davy, on breaking some lumps of coal under water, also ascertained that they gave off inflammable gas. the supposition that the coal strata have been formed under a pressure greater than that of the atmosphere, may furnish a clue to the comprehension of this phenomenon. on some occasions the pitmen have opened with their picks crevices, or fissures, in the coal or shale, which have emitted as much as seven hundred hogsheads of _fire-damp_ in a minute. these _blowers_, as they are technically termed, have been known to continue in a state of activity for many months, or even years together;[ ] a phenomenon which clearly shows that the carburetted hydrogen must have existed in the cavities of the strata in a very highly compressed, if not actually in a liquid state, and which, on the diminution of pressure, has resumed its elastic form. [ ] sir james lowther found a uniform current of this description produced in one of his mines for the space of two years and nine months. phil. trans, vol. . p. . all the sources of carburetted hydrogen would appear to unite in the deep and valuable collieries situated between the great north road and the sea. their air courses are thirty or forty miles in length; and here, as might be expected, the most tremendous explosions have happened. old workings, likewise, upon being broken into, have not unfrequently been found filled with this gas, and which, by mingling itself with the common air, has converted the whole atmosphere of the mine into a magazine of _fire-damp_. on the approach of a candle, it is in an instant kindled: the expanding fluid drives before it a roaring whirlwind of flaming air, which tears up every thing in its progress, scorching some of the miners to a cinder, and burying others under enormous ruins shaken from the roof; when thundering to the shafts, it converts the mine, as it were, into an enormous piece of artillery, and wastes its fury in a discharge of thick clouds of coal-dust, stones, and timber, together with the limbs and mangled bodies of men and horses. but this first, though apparently the most appalling, is not the most destructive effect of these subterraneous combustions. all the _stoppings_ and trapdoors of the mine being blown down by the violence of the concussion, and the atmospheric current entirely excluded from the workings, such of the miners as may have survived the discharge are doomed to the more painful and lingering death of suffocation from the _after-damp_, or _stythe_, as it is termed, which immediately results from the combustion, and occupies the vacuum necessarily produced by it. as the phenomena accompanying these explosions are always of the same description, to relate the numerous recorded histories of such accidents would be only to multiply pictures of death and human suffering, without an adequate object: it is, however, essential to the just comprehension of the subject, that the reader should receive at least one well-authenticated account, in all its terrific details; and i have accordingly selected that which was originally drawn up with much accuracy and feeling by the reverend john hodgson, and which is prefixed to the funeral sermon preached on the occasion, and subsequently published by that gentleman. the accident occurred at felling colliery, near sunderland, on the th of may, in the year . this mine was considered by the workmen as a model of perfection, both with regard to the purity of its air, and the arrangements of its machinery. the concern was in the highest degree prosperous; and no accident, except a trifling explosion which slightly scorched two or three pitmen, had ever occurred. two _shifts_, or sets of men, were constantly employed, the first of which entered the mine at four, and were relieved at their working posts by the next set at eleven o'clock in the morning; but such was the confidence of the pitmen in the safety of this mine, that the second shift of men were often at their posts before the first set had left them; and such happened to be the case on the following unhappy occasion. about half past eleven, on the morning of the th of may, the neighbouring villages were alarmed by a tremendous explosion. the subterraneous fire broke forth with two heavy discharges from the shaft called the '_john pit_,' which was one hundred and two fathoms deep, and were almost immediately followed by one from that termed the '_william pit_,' a slight trembling, as if from an earthquake, was felt for about half a mile around the workings; and the noise of the explosion, though dull, was heard to the distance of three or four miles, and greatly resembled an unsteady fire of infantry. immense quantities of dust and small coal accompanied these blasts, and rose high into the air, in the form of an inverted cone. the heaviest part of the ejected matter, such as masses of timber, and fragments of coal, fell near the pit, but the dust, borne away by a strong west wind, fell in a continued shower to the distance of a mile and a half; and in the village of heworth, it caused a gloom, like that of early twilight, and so covered the roads that the footsteps of passengers were strongly imprinted on them. as soon as the explosion had been heard, the wives and children of the pitmen rushed to the working pit. wildness and terror were pictured in every countenance. the crowd thickened from every side, and in a very short period several hundred persons had collected together; and the air resounded with exclamations of despair for the fate of husbands, parents, and children. the machinery having been rendered useless by the eruption, the rope of the _gin_ was sent down the shaft with all possible expedition. in the absence of horses, a number of men, who seemed to acquire strength as the necessity for it increased, applied their shoulders to the _starts_, or shafts of the gin, and worked it with astonishing expedition. by twelve o'clock, thirty-two persons, all that survived this dreadful catastrophe, had been brought to daylight, but of these three boys lived only a few hours. the dead bodies of two boys, miserably scorched and shattered, were also brought up at the same time. twenty-nine persons, then, were all who were left to relate what they had observed of the appearances and effect of the explosion. one hundred and twenty-one were in the mine when it happened, eighty-seven of whom remained in the workings. eight persons had fortunately come up a short time before the accident. those who had their friends restored, hastened with them from the scene of destruction, and for a while appeared to suffer as much from an excess of joy, as they had a short time before from the depth of despair; while those who were yet in the agony of suspense, filled the air with shrieks and howlings, and ran about wringing their hands and throwing their bodies into the most frantic and extravagant gestures. as not one of the pitmen had escaped from the mine by the only avenue open to them, the apprehension for their safety momentarily increased, and at a quarter after twelve o'clock, nine persons descended the john pit, with the faint hope that some might still survive. as the fire-damp would have been instantly ignited by candles, they lighted their way by _steel-mills_;[ ] and knowing that a great number of the miners must have been at the crane when the explosion happened, they at once attempted to reach that spot: their progress, however, was very soon intercepted by the prevalence of _choak damp_, and the sparks from their steel-mill fell into it like dark drops of blood: deprived therefore of light, and nearly suffocated by the noxious atmosphere, they retraced their steps towards the shaft, but they were shortly stopped by a thick smoke which stood like a wall before them. here their steel-mills became entirely useless, and the chance of their ever finding any of their companions alive entirely hopeless; to which should also be added the horror arising from the conviction of the mine being on fire, and the probability of a second explosion occurring at the next moment, and of their being buried in the ruins it would occasion. [ ] steel-mills are small machines, which give light by turning a cylinder of steel against a piece of flint. sir james lowther had observed early in the last century, that the fire-damp in its usual form was not inflammable by sparks from flint and steel; and it appears that a person in his employment invented the machine in question. at two o'clock, five of the intrepid persons who had thus nobly volunteered their assistance, ascended; two were still in the shaft, and the other two remained below, when a second explosion, much less severe, however, than the first, excited amongst the relatives of those entombed in the mine still more frightful expressions of grief and despair. the persons in the shaft experienced but little inconvenience from this fresh eruption, while those below, on hearing the distant growlings, immediately threw themselves flat on their faces, and in this posture, by keeping a firm hold on a strong wooden prop, they felt no other annoyance from the blast than that of having their bodies tossed in various directions, in the manner that a buoy is heaved by the waves of the sea. as soon as the atmospheric current returned down the shaft, they were safely drawn to the light. as each came up, he was surrounded by a group of anxious enquirers; but not a ray of hope could be elicited; and the second explosion so strongly corroborated their account of the impure state of the mine, that their assertions for the present seemed to obtain credit. this impression, however, was but of short duration,--hope still lingered; they recollected that persons had survived similar accidents, and that, upon opening the mine, they had been found alive after considerable intervals. three miners, for instance, had been shut up for forty days in a pit near byker, and during the whole of that period had subsisted on candles and horse-beans. persons too were not wanting to agitate the minds of the relatives with disbelief in the report of the pitmen who had lately descended to explore the mine. it was suggested to them, that want of courage, or bribery, might have induced them to magnify the danger, and to represent the impossibility of reaching the bodies of the unfortunate sufferers. by this species of wicked industry, the grief of the neighbourhood began to change its gloomy, for an irritable aspect. the proposition to exclude the atmospheric air from the mine, in order to extinguish the fire, was received with the cries of _murder!_--and with the determination to oppose such a proceeding by violence. many of the widows lingered about the mouth of the pit during the whole of the night with the hope of hearing the cries of a husband or a son. on tuesday the th, that natural propensity in the human mind to derive gratification from spectacles of horror, was exemplified in a very striking manner. an immense crowd of colliers from various parts, but more especially from the banks of the river wear, assembled around the pit, and were clamorous in their reproaches of the persons concerned in the management of the mine, accusing them of want of perseverance in their attempts to rescue the unhappy sufferers. every one had some successful adventure to relate; all were liberal in their professions of readiness to give assistance; but not one was found hardy enough to enter the jaws of the burning cavern. the leaders of this outcry, however, who had been led into error by an impulse which did honour to their hearts, were soon brought to listen with patience to a relation of all the circumstances of the explosion, and of the reasons for concluding that the mine was then actually on fire, and the persons enclosed in it beyond the hope of recovery. they very candidly allowed, after this explanation, the impracticability of any attempt to reach the bodies of the sufferers, until the fire was extinguished; and they accordingly urged the propriety of excluding from the mine the access of air, as the only means of accomplishing the object. at the same time, the proprietors gave the strongest assurances to the multitude, that if any project could be devised for the recovery of their friends, no cost or labour should be spared in executing it; that, if any person could be found willing to enter the mine, every facility and assistance should be afforded him; but, as they were assured by the most eminent viewers that the workings were inaccessible, they would not hold out any reward for the attempt,--they would not be accessary to the death of any one, either by persuasion or bribery. at the clamorous solicitation, however, of the populace, two persons again descended the shaft, and very nearly lost their lives in the attempt. the report of these last adventurers, in a great measure, convinced the people of the impossibility of their friends' survival in so deadly an atmosphere, and reconciled them to the plan of excluding the air. the operation was accordingly commenced, and it proceeded without interruption; but from various accidents, more than a month elapsed before the mine was in a state to admit of examination; and during this interval, numerous were the idle tales which had been circulated throughout the country. several of the sufferers, it was said, had found their way to the shafts, and been recovered. their number even had been circumstantially told--how they had subsisted on candles, oats, and beans, and how they had heard the different persons who explored the mine in the hope of rescuing them. some conjuror too, it was said, had set his spells and divinations to work, and had penetrated all the secrets of the mine. he had discovered one famishing group receiving drops of water from the roof, another eating their shoes and clothes, and many other similar pictures of horror. these inventions were carefully related to the widows, and they produced the effect of daily harrowing up afresh their sorrows; indeed, it seemed the chief employment of some to indulge in a kind of insane sport with their own and their neighbours' calamity. the morning of wednesday the th of july having been appointed for exploring the workings, the distress of the neighbourhood was again renewed at an early hour: a great concourse of people assembled; some, out of curiosity, to witness the commencement of an undertaking full of sadness and danger,--some to excite the revenge, or to aggravate the sorrows, of the relatives by calumnies and reproaches, for the sole purpose of mischief; but the greater part came with broken hearts and streaming eyes, in expectation of seeing the mangled corpse of a father, brother, husband, or son. the _shifts_ of men employed in this doleful and unwholesome work were generally about eight in number. they were four hours in, and eight hours out of the mine; so that each individual wrought two shifts every twenty-four hours. when the first shift of men came up, a message was dispatched for a number of coffins to be in readiness at the mouth of the pit. ninety-two had been prepared, and they had to pass by the village of low felling, in their way to the mine. as soon as a cart-load of them was seen, the howling of the women, who, hitherto secluded in their dwellings, had now begun to assemble about their doors, came on the breeze in slow fitful gusts, which presaged a scene of the greatest distress and confusion. the bodies were found under various circumstances: one miner, from his position, must have been sleeping when the explosion happened, and had never opened his eyes. in one spot were found twenty-one bodies in ghastly confusion,--some like mummies, scorched as dry as if they had been baked; one wanted its head, another an arm--the scene was most terrific: the power of the fire was visible upon all, but its effects were very various; while some were almost torn to pieces, there were others who appeared as if they had sunk down overpowered by sleep. every family had made arrangements for receiving the dead bodies of their kindred; but dr. ramsay having given his opinion, that such a proceeding might spread a putrid fever through the neighbourhood, and the first body when exposed to observation having presented a most horrid and corrupt appearance, the people very properly consented to have each body interred as soon as it was discovered, on condition that the hearse, in its way to the chapel-yard, should pass by the door of the deceased. from the th of july to the th of september, the heart-rending scene of mothers and widows examining the putrid bodies of their sons and husbands, for marks by which to identify them, was daily renewed; but very few of them were recognised by any personal mark--they were too much mangled and scorched to retain any of their features: their clothes, tobacco-boxes, and shoes, were therefore the only indications by which they could be identified. the total loss from this terrible accident was ninety-two pitmen; while forty widows, sixty girls, and twenty-six boys, comprising in all one hundred and twenty six persons, were thrown upon the benevolence of the public. it was impossible that an event of such awful magnitude should not have deeply affected every humane person resident in the district. nothing, in short, could exceed the anxiety which was manifested on the occasion; but, most unfortunately, there existed an invincible prejudice against every proposition that could be offered, from a general impression as to the utter hopelessness of any attempt to discover a remedy. a few philosophic individuals, however, did form themselves, as we shall presently learn, into an association for the laudable purpose of inviting the attention of scientific men to the subject, and of obtaining from them any suggestions which might lead to a more secure method of lighting the mines. to the reverend dr. gray, the present lord bishop of bristol, who, at the period to which i allude, was the rector of bishop-wearmouth, and one of the most zealous and intelligent members of the association, i beg to offer my public acknowledgments and thanks for the several highly interesting communications and letters with which his lordship has obliged me, and by means of which i have been enabled to present to the scientific world a complete history of those proceedings which have so happily led to a discovery, of which it is not too much to say that it is, at once, the pride of science, the triumph of humanity, and the glory of the age in which we live. in a letter i had lately the honour of receiving from that learned prelate, his lordship says, "it was at a time when all relief was deemed hopeless, that mr. wilkinson, a barrister in london, and a gentleman distinguished for the humanity of his disposition, suggested the expediency of establishing a society for the purpose of enquiring whether any, and what, methods of security might be adopted for the prevention of those accidents so frequently occurring in the collieries of northumberland and durham. "in consequence of this benevolent suggestion, a society was established at bishop-wearmouth, on the st of october , by sir ralph milbanke, afterwards sir ralph noel, dr. gray, dr. pemberton, mr. robinson, mr. stephenson, and several other gentlemen. it was entitled, 'a society for preventing accidents in coal-mines;' and it immediately obtained the patronage of the bishop of durham, the duke of northumberland, and other noblemen and gentlemen. "a very few days before the first meeting, twenty-seven persons had been killed in a colliery in which sir ralph milbanke had an interest, and he was called upon at the meeting to state the particulars of the accident. at that time there was such little expectation that any means could be devised to prevent the occurrence of these explosions, that the object of the gentlemen who convened the meeting, however humane in principle, was considered by the persons present as chimerical and visionary. the society, however, amidst many difficulties and considerable discouragement, and a perpetual harass by the offer of impracticable schemes from every quarter, nevertheless persevered in their meetings, and succeeded in establishing a communication and correspondence with other societies in different parts of the kingdom."[ ] [ ] it is unnecessary to enumerate the various schemes that have been proposed to prevent accidents from fire-damp. some were unquestionably of value, and might, by their adoption, have diminished the frequency of explosions; others were visionary, or wholly impracticable. it was proposed, for instance, to fill the mine with an atmosphere of chlorine, which by entering into chemical union with the carburetted hydrogen, might disarm it of its power. dr. murray, in a paper published in the transactions of the royal society of edinburgh, suggests the use of a lamp that shall be supplied with air from the ground of the pit, by means of a long flexible tube, upon the false assumption that the fire-damp alone occupies the higher parts of the mine. mr. w. brandling also constructed a safe-lamp, which, like that of dr. murray, was fed by air introduced through a long flexible tube reaching to the floor of the mine. in addition to which, he attached to the top of the lantern a pair of double bellows, by the aid of which he at the same time drew out the contaminated air from the interior of the lamp, and sucked in, through the flexible tube, a fresh portion to supply its place. to say nothing of the inefficacy and inconvenience of the long tube, the bellows possessed the additional objection of frequently puffing out the light. one of the most active and intelligent members of the "society for preventing accidents in coal mines," dr. clanny, had for some time paid particular attention to the object in contemplation. he first suggested the idea of an insulated lamp, of which an account appeared in the philosophical transactions for . in , he invented a steam safety-lamp, constructed of the strongest tinned iron, with thick flint glass in front. in this machine, the air of the coal mine passes in a current through a tube, and mixing with the steam, before it can arrive at the light, burns steadily in the wick of the lamp alone. this lamp has the valuable property of remaining cool. it has been much used in the herrington mill pit, the whitefield pit, and the engine pit. "one of the projects offered was, that electrical machines should be employed, with ramifications to extend through all the departments of the collieries, and which were to be excited in discharging their fluid in constant succession, in order gradually to destroy the inflammable air. many other suggestions were proposed, the principal of which were formed with the intention of purifying the air of the pits by chemical processes, or by forcing in large quantities of atmospheric air, through pipes and tunnels, &c. "the society, although it received some distinguished patronage, was not furnished with means sufficiently ample for exciting emulation by premiums, or even for defraying the expenses of intelligent artisans; and it unfortunately lost a considerable portion of its funds by the failure of the wear bank. "amongst the applications which more particularly excited the attention of the society, was that of mr. ryan of donegal, who objected to the principle upon which the working of collieries was carried on. he conceived that they should be originally constructed at the commencement of the working, with a view to admit the escape of the hydrogen gas to the highest parts of the colliery. he proposed to ventilate even the foulest pits, and the attention of the gentlemen proprietors, or occupiers of collieries, in the neighbourhood of newcastle, was called upon at public meetings, and an enquiry set on foot with respect to the validity of his pretensions. some gentlemen were even deputed to proceed into staffordshire to ascertain the nature and extent of his services in that county, where he had been for some time employed. an offer was also made to place under his management the hecton pit, at hepburn, which was particularly foul; but a difference of opinion having arisen as to the efficacy of his plan, he did not consider himself sufficiently encouraged to proceed, and he left the country dissatisfied. he afterwards received the gold medal from the society for promoting the arts and sciences." the society having as yet effected but little towards the great object of their deliberations, the chairman of the committee, dr. gray, who was generally acquainted with sir humphry davy, judged it expedient to direct his attention to a subject, upon which, of all men of science, he appeared to be the best calculated to bring his extensive stores of chemical knowledge to a practical bearing. as the life of this valuable man is now closed, and as every incident in it is interesting as connected with the advancement of philosophical knowledge, and especially of chemical discoveries important to the welfare of mankind, it may be worth while to enter into a review of the proceedings which were adopted upon this occasion, in order to trace the progress of the discoveries which were made, and the methods by which he arrived at his conclusions. dr. gray, the chairman of the committee, having addressed to him a letter with a view to engage him in an investigation so important to society, received from him the following answer. to the reverend dr. gray. sir, august , . i had the honour of receiving the letter which you addressed to me in london, at this place, and i am much obliged to you for calling my attention to so important a subject. it will give me great satisfaction if my chemical knowledge can be of any use in an enquiry so interesting to humanity, and i beg you will assure the committee of my readiness to co-operate with them in any experiments or investigations on the subject. if you think my visiting the mines can be of any use, i will cheerfully do so. there appears to me to be several modes of destroying the fire-damp without danger; but the difficulty is to ascertain when it is present, without introducing lights which may inflame it. i have thought of two species of lights which have no power of inflaming the gas which is the cause of the fire-damp, but i have not here the means of ascertaining whether they will be sufficiently luminous to enable the workmen to carry on their business. they can be easily procured, and at a cheaper rate than candles. i do not recollect any thing of mr. ryan's plan: it is possible that it has been mentioned to me in general conversation, and that i have forgotten it. if it has been communicated to me in any other way, it has made no impression on my memory. i shall be here for ten days longer, and on my return south, will visit any place you will be kind enough to point out to me, where i may be able to acquire information on the subject of the coal gas. should the bishop of durham be at auckland, i shall pay my respects to his lordship on my return. i have the honour to be, dear sir, with much respect, your obedient humble servant, h. davy. at lord somerville's, near melrose, n. b. to the same. sir, melrose, august , . i received your letter, which followed me to the moors, where i have been shooting with lord somerville. i should have replied to it before this time, but we were in a part of the highlands where there was no post. i am very grateful to you for the obliging invitation it contains. i propose to leave the tweed side on tuesday or wednesday, so that i shall be at newcastle either on wednesday or thursday. if you will have the kindness to inform me by a letter, addressed at the post office, where i can find the gentleman you mention, i will call upon him, and do any thing in my power to assist the investigation in that neighbourhood. i regret that i cannot say positively whether i shall be at newcastle on wednesday or thursday; for i have some business at kelso which may detain me for a night, or it may be finished immediately. i am travelling as a bachelor, and will do myself the honour of paying my respects to you at bishop-wearmouth towards the end of the week. i am, sir, with much respect, your obedient humble servant, h. davy. the gentleman alluded to in the preceding letter, and to whom dr. gray wished sir h. davy to apply, was mr. buddle, a person whose extensive practical knowledge has justly entitled him to be considered as the highest authority on all subjects connected with the art of mining, and who has conferred inestimable benefits on the mining interests by the introduction of successful methods of ventilation. the account of his interview with sir h. davy is communicated in the following letter. mr. buddle to dr. gray. wall's-end colliery, august , . sir, permit me to offer my best acknowledgments for the opportunity which your attention to the cause of humanity has afforded me of being introduced to sir humphry davy. i was this morning favoured with a call from him, and he was accompanied by the rev. mr. hodgson. he made particular enquiries into the nature of the danger arising from the discharge of the inflammable gas in our mines. i shall supply him with a quantity of the gas to analyze; and he has given me reason to expect that a substitute may be found for the steel mill, which will not fire the gas. he seems also to think it possible to generate a gas, at a moderate expense, which, by mixing with the atmospheric current, will so far neutralize the inflammable air, as to prevent it firing at the candles of the workmen. if he should be so fortunate as to succeed in either the one or the other of these points, he will render the most essential benefit to the mining interest of this country, and to the cause of humanity in particular. i have little doubt but it will be gratifying to you to be informed, that progress is making towards the establishment of a permanent fund for the relief of sufferers by accident and sickness in the collieries of this district. i have the pleasure to remain, with great respect, sir, your most obedient, humble servant, john buddle. sir h. davy on his return to london, having been supplied by mr. buddle with various specimens of _fire-damp_, proceeded, in the first instance, to submit to a minute chemical examination the substance with which he had to contend. in less than a fortnight, he informed dr. gray by letter, that he had discovered some new and unexpected properties in the gas, which had led to no less than four different plans for lighting the mines with safety. to the reverend dr. gray. royal institution, oct. . my dear sir, as it was the consequence of your invitation that i endeavoured to investigate the nature of the fire-damp, i owe to you the first notice of the progress of my experiments. my results have been successful far beyond my expectations. i shall enclose a little sketch of my views on the subject; and i hope in a few days to be able to send a paper with the apparatus for the committee. i trust the _safe lamp_ will answer all the objects of the collier. i consider this at present as a _private_ communication. i wish you to examine the lamps i have had constructed, before you give any account of my labours to the committee. i have never received so much pleasure from the result of any of my chemical labours; for i trust the cause of humanity will gain something by it. i beg of you to present my best respects to mrs. gray, and to remember me to your son. i am, my dear sir, with many thanks for your hospitality and kindness when i was at sunderland, your obliged servant, h. davy. to the same. london, october , . my dear sir, i sent yesterday a sketch of my results on the fire-damp. we have lately heard so much of east[ ] shields, that by a strange accident i confounded it with bishop-wearmouth, and addressed your letter to east shields. i could not find any body to frank it, and you will find it a heavy packet; however, i could not lose a moment in giving you an account of results which i hope may be useful to humanity. if my letter has not reached you, it will be found at the post office, east shields. with respects to mrs. gray, i am, my dear sir, very sincerely yours, h. davy. [ ] _quere_--south shields. the sketch alluded to in the foregoing letter, has been kindly placed in my hands by the bishop of bristol; it possesses considerable interest as an original document, displaying his earliest views, and tending to illustrate the history of their progress. "the fire-damp i find, by chemical analysis, to be (as it has been always supposed) a hydro-carbonate. it is a chemical combination of hydrogen gas and carbon, in the proportion of by weight of hydrogen gas, and - / of charcoal. "i find it will not explode, if mixed with less than six times, or more than fourteen times its volume of atmospheric air. air, when rendered impure by the combustion of a candle, but in which the candle will still burn, will not explode the gas from the mines; and when a lamp or candle is made to burn in a close vessel having apertures only above and below, an _explosive mixture_ of gas admitted _merely enlarges_ the light, and then gradually extinguishes it without explosion. again,--the gas mixed in any proportion with common air, i have discovered, _will not explode_ in a _small tube_, the diameter of which is less than / th of an inch, or even a larger tube, if there is a mechanical force urging the gas through this tube. "explosive mixtures of this gas with air require much stronger heat for their explosion than mixtures of common inflammable gas.[ ] red-hot charcoal, made so as not to flame, if blown up by a mixture of the mine gas and common air, does not explode it, but gives light in it; and iron, to cause the explosion of mixtures of this gas with air, must be made _white_-hot. "the discovery of these curious and unexpected properties of the gas, leads to several practical methods of lighting the mines without any danger of explosion. "the first and simplest is what i shall call the _safe lamp_, in which a candle or a lamp burns in a safe lantern which is air-tight in the sides, which has tubes below for admitting air, a chamber above, and a chimney for the foul air to pass through; and this is as portable as a common lantern, and not much more expensive. in this, the light never burns in its full quantity of air, and therefore is more feeble than that of the common candle. "the second is the _blowing lamp_. in this, the candle or lamp burns in a close lantern, having a tube below of small diameter for admitting air, which is thrown in by a small pair of bellows, and a tube above of the same diameter, furnished with a cup filled with oil. this burns brighter than the simple safe lamp, and is extinguished by explosive mixtures of the fire-damp. in this apparatus the candle may be made to burn as bright as in the air; and supposing an explosion to be made in it, it cannot reach to the external air. "the third is the _piston lamp_, in which the candle is made to burn in a small glass lantern furnished with a piston, so constructed as to admit of air being supplied and thrown into it without any communication between the burner and the external air: this apparatus is not larger than the steel-mill, but it is more expensive than the other, costing from twenty-two to twenty-four shillings. "these lamps are all extinguished when the air becomes so polluted with fire-damp as to be explosive. "there is a fourth lamp, by means of which any _blowers_ may be examined in air in which respiration cannot be carried on: that is, the _charcoal lamp_. this consists of a small iron cage on a stand, containing small pieces of _very well burnt_ charcoal blown up to a red heat. this light will not inflame any mixtures of air with fire-damp.[ ] "of these inventions, the _safe lamp_, which is the simplest, is likewise the one which affords the most perfect security, and requires no more care or attention than the common candle, and when the air in mines becomes improper for respiration, it is extinguished, and the workmen ought immediately to leave the place till a proper quantity of atmospheric air can be supplied by ventilation. "i have made many experiments on these lamps with the genuine fire-damp taken from a blower in the hepburn colliery, collected under the inspection of mr. dunn, and sent to me by the reverend mr. hodgson. my results have been always unequivocal. "i shall immediately send models of the different lamps to such of the mines as are exposed to danger from explosion; and it will be the highest gratification to me to have assisted by my efforts a cause so interesting to humanity." [ ] _olefiant_ gas, when mixed with such proportions of common air as to render it explosive, is fired both by charcoal and iron heated to a dull-red heat. _gaseous oxide of carbon_, which explodes when mixed with two parts of air, is likewise inflammable by red-hot iron, and charcoal. the case is the same with _sulphuretted hydrogen_. [ ] "in addition to these four lamps, we learn from an appendix to his paper in the philosophical transactions, that in the beginning of his enquiries, he constructed a close lantern, which he called the _fire-valve lantern_; in which the candle or lamp burnt with its full quantity of air, admitted from an aperture below, till the air began to be mixed with fire-damp, when, as the fire-damp increased the flame, a thermometrical spring at the top of the lantern, made of brass and steel, riveted together, and in a curved form, expanded, moved a valve in the chimney, diminished the circulation of air, and extinguished the flame. he did not, however, pursue this invention, after he had discovered the properties of the fire-damp, on which his safety-lamp is founded." contrary to the wish expressed by sir humphry davy, the foregoing communication was inadvertently read at a public meeting of the coal-trade, which was held at newcastle on the rd of november: a circumstance which occasioned some embarrassment at the time, but is satisfactorily explained in the following letter from sir humphry. to the reverend dr. gray. , grosvenor street, dec. , . my dear sir, my communication to ---- was, like that i made to you, intended to be _private_; he has however written to me to apologize for having made it known at newcastle, stating, that having seen a notice of my results in the paper, the motive, as he conceived, for withholding it was at an end, as he considered my only reason for wishing to keep back my results from the public eye was the conviction that they might be rendered more perfect, and this i have now fully proved. i trust i shall be able in a very few days to send you a model of a lantern nearly as simple as a common glass lantern, and which _cannot_ communicate explosion to the fire-damp. i will send another to newcastle, and i will likewise send you the copy of my paper, which you may reprint in any form you please; you will find my acknowledgments to you publicly stated. my principles are these: _first_, a certain mixture of azote and carbonic acid prevents the explosion of the fire-damp, and this mixture is necessarily formed in the safe lantern;--_secondly_, the fire-damp _will not explode_ in tubes or feeders of a certain small diameter. the ingress into, and egress of air from my lantern is through such tubes or feeders; and therefore, when an explosion is _artificially_ made in the safe lantern, it does not communicate to the external air. i have made two or three lanterns of different forms. experience must determine which will be the most convenient. should there be a little delay in sending them, it will be the fault of the manufacturer. it is impossible to conceive the difficulty of getting any thing made in london which is not in the common routine of business; and i should be very sorry to send you any thing imperfectly executed. with best respects to mrs. gray, i am, my dear sir, very sincerely your obliged servant, h. davy. the paper alluded to in the preceding letter, entitled, "on the fire-damp of coal mines, and on methods of lighting the mine so as to prevent its explosion," was read before the royal society on the th of november, . in this memoir he communicates the results of some chemical experiments upon the nature of the fire-damp, and announces the existence of certain properties in that gas, which had previously escaped observation, and which leads to very simple methods of lighting the mines without danger. he confirms the opinion of dr. henry, and other chemists, as to the fire-damp being light carburetted hydrogen gas, and analogous to the inflammable gas of marshes; but he found that the degree of its combustibility differed most materially from that of the other common inflammable gases, which it is well known will explode by the contact of both red-hot iron and charcoal; whereas well-burned charcoal, ignited to the strongest red heat, did not explode any mixture of the air and of the fire-damp; and a fire made of well-burned charcoal, that is to say, of charcoal that will burn without flame, was actually blown up to whiteness by an explosive mixture containing the fire-damp without producing its inflammation.[ ] an iron rod also, at the highest degree of _red_ heat, and even at the common degree of _white_ heat, did not inflame explosive mixtures of the fire-damp; but when in brilliant combustion, it produced the effect. [ ] whence he observes that, if it be necessary to be present in a part of the mine where the fire-damp is explosive, for the purpose of clearing the workings, taking away pillars of coal, or other objects, the workmen may be safely lighted by a fire made of charcoal, which burns without flame. he moreover found that the heat produced by the combustion of the fire-damp was much less than that occasioned by most other inflammable gases under similar circumstances; and hence its explosion was accompanied with comparatively less expansion: a circumstance of obvious importance in connection with the propagation of its flame. numerous experiments were likewise instituted by him with a view to determine the proportions of air with which the fire-damp required to be mixed, in order to produce an explosive atmosphere; and he found the quantity necessary for that purpose to be very considerable; even when mixed with three or nearly four times its bulk of air, it burnt quietly in the atmosphere, and extinguished a taper. when mixed with between five and six times its volume of air, it exploded freely. the mixture which seemed to possess the greatest explosive power was that of seven or eight parts of air to one of gas. on adding azote and carbonic acid in different proportions to explosive mixtures of fire-damp, it was observed that, even in very small quantities, these gases diminished the velocity of the inflammation, or altogether destroyed it. in this stage of the enquiry, the important fact was discovered, that explosive mixtures could not be fired in metallic tubes of certain lengths and diameters.[ ] in exploding, for instance, a mixture of one part of gas from the distillation of coal, and eight parts of air, in a tube of a quarter of an inch in diameter and a foot long, more than a second was required before the flame reached from one end of the tube to the other; and not any mixture could be made to explode in a glass tube of one-seventh of an inch in diameter. in pursuing these experiments, he found that, by diminishing its diameter, he might in the same ratio shorten the tube without danger; and that the same principle of security was obtained by diminishing the length and increasing the number of the tubes, so that a great number of small apertures would not pass explosion when their depth was equal to their diameter. this fact led him to trials upon sieves made of wire-gauze, or metallic plates perforated with numerous small holes, and he found that it was impossible to pass explosions through them.[ ] [ ] mr. tennant had, some years before, observed that mixtures of the gas, from the distillation of coal, and air, would not explode in very small tubes. davy, however, was not aware of this at the time of his researches. [ ] the apertures in the gauze should not be more than one-twentieth of an inch square. as the fire-damp is not inflamed by ignited wire, the thickness of the wire is not of importance; but wire from one-fortieth to one-sixtieth of an inch in diameter is the most convenient. in reasoning upon these several phenomena, it occurred to him, that as a high temperature was required for the inflammation of the fire-damp, and as it produced in burning, comparatively, _a small degree_ of heat, the effect of carbonic acid and azote, as well as that of the surfaces of small tubes, in preventing its explosion, depended upon their cooling powers; that is to say, upon their lowering the temperature of the exploding mixture to such a degree, that it was no longer sufficient for its continuous inflammation. in support of this theory, he ascertained that metallic tubes resisted the passage of the flame more powerfully than glass tubes of similar lengths and diameters, metal being the better conductor of heat; and that carbonic acid was more effective than azote in depriving the fire-damp of its explosive power, in consequence, as he considered, of its greater capacity for heat, and likewise of a higher conducting power connected with its greater density. in this short statement, the reader is presented with the whole theory and operation of the safety-lamp, which is nothing more than an apparatus by which the inflammable air, upon exploding in its interior, cannot pass out without being so far cooled, as to deprive it of the power of communicating inflammation to the surrounding atmosphere. the principle having been once discovered, it was easy to adopt and multiply practical applications of it. from the result of these researches, it became at once evident, that to light mines infested with fire-damp, with perfect security, it was only necessary to use an air-tight lantern, supplied with air from tubes of small diameter, through which explosions cannot pass, and with a chimney, on a similar principle, at the upper part, to carry off the foul air. a common lantern, to be adapted to the purpose, merely required to be made air-tight in the door and sides, and to be furnished with the chimney, and the system of safety apertures below and above the flame of the lamp. such, in fact, was davy's first safety-lamp; and having afterwards varied the arrangement of the tubes in different ways, he at length exchanged them for canals, which consisted of close concentric hollow metallic cylinders of different diameter, so placed together as to form circular canals of the diameter of from one-twenty-fifth to one fortieth of an inch; and of an inch and seven-tenths in length; by which air is admitted in much larger quantities than by the small tubes, and they are moreover much superior to the latter in practical application. he also found, that longitudinal air-canals of metal might be employed with the same security as circular canals; and that a few pieces of tin plate, soldered together with wires to regulate the diameter of the canal, answered the purpose of the feeder or safe chimney, as well as drawn cylinders of brass. the subjoined explanatory sketches will assist in rendering the scheme intelligible, and obviate the possibility of any misconception of the subject. [illustration] fig. . represents the first safe lantern, with its air-feeder and chimney furnished with safety metallic canals. the sides are of horn or glass, made air-tight by putty or cement. a. is the lamp through which the circular air-feeding canals pass. b. is the chimney containing four such canals; above it is a hollow cylinder, with a cap to prevent dust from passing into the chimney. c. is the hole for admitting oil. f. is the rim round the bottom of the lantern, to enable it to bear motion. [illustration] fig. . exhibits an enlarged view of the safety concentric canals, which, if one-twenty-fifth of an inch in diameter, must not be less than two inches in exterior circumference, and one-seventh of an inch high. [illustration] fig. . exhibits the longitudinal safety canals. [illustration] fig. . represents a safety-lamp having a glass chimney, covered with tin-plate, and the safety apertures in a cylinder with a covering above: the lower part is the same as in the lantern. [illustration] fig. . a glass tube furnished with _flame sieves_, in which a common candle may be burnt. a a. the flame sieves. b. a little plate of metal to prevent the upper flame sieve from being acted on by the current of hot air. during the short visit of sir humphry davy at bishop wearmouth, he saw the lamp which dr. clanny was then engaged in perfecting. it has been already observed, that it was secured against the effects of fire-damp by being supplied with atmospheric air previously conveyed through water.[ ] the machinery of this lamp was far too cumbrous to be of general use; but its inventor was justly commended by davy for his ingenuity and perseverance. it unfortunately happened that, in consequence of some erroneous representations made to dr. clanny, he received the impression that sir humphry had not been disposed to treat his invention with sufficient respect, nor had given him the credit to which he was so justly entitled. this suspicion, which had been long industriously kept alive, was however ultimately removed. [ ] m. de humboldt conceived and executed the plan of a lamp in , for giving a safe light in mines, upon a similar principle of entire insulation from the air.--_journal des mines_, t. viii. p. . the following letter refers to this unfortunate circumstance. i have adverted to it in these memoirs, for the purpose of showing what an unfair spirit of rivalry, and what a succession of petty jealousies were excited by those generous and disinterested labours of davy, which ought to have called forth nothing but the most lively expressions of gratitude for his services, and admiration of his genius. to the reverend dr. gray. , grosvenor street, december . my dear sir, a friend of mine has sent me a newspaper--the tyne mercury, containing a very foolish libel upon me. it states, amongst other things, that i did not mention dr. clanny, or his lamp, in my late paper read before the royal society; whereas i mentioned his lamp as a very ingenious contrivance, and named him amongst the gentlemen who obligingly furnished me with information upon the subject. it will be needless for me to point out to you that my lamp has no one principle in common with that of dr. clanny. he forces in his air through water by bellows. in mine, the air passes through safety canals without any mechanical assistance. mine is a common lantern made close, and furnished with safety canals. i hope i shall not hear that dr. clanny has in any way authorized or promoted so improper a statement as that in the tyne mercury; indeed, i do not think it possible. i have at last obtained a complete model of my lamp, after many disappointments from the instrument-maker. i hope in a few days to send you a _safe lantern_, as portable as a common-made one, and the perfect security of which is demonstrable. i am, my dear sir, your sincerely obliged, h. davy. to the same. grosvenor street, december . my dear sir, i shall inclose the first sheet of my paper, and shall be glad to preface it by some observations when you reprint it. i shall forward my lanterns and lamps to you in a few days. they are _absolutely_ safe; and if the miners have any more explosions from their light, it will be their own fault. you will find, when you see my construction, that the principles as well as the execution are entirely new. you will find in the second sheet of my paper, which i hope to be able to send to-morrow, the _principles_ of _security_, and its limits unfolded. i am, my dear sir, very sincerely yours, h. davy. to the same. london, january , . my dear sir, i fear you will have accused me of procrastination in delaying to send you my papers and my lamps. the papers read to the royal society have been printed; but during the period that has elapsed since i last wrote to you, i have made a discovery much more important than those which i have already had the honour of communicating to you. i have made very simple and economical lanterns, and candle guards, which are not only _absolutely safe_, but which give light by means of the fire-damp, and which, while they disarm this destructive agent, make it useful to the miner. this discovery is a consequence of that which i communicated to you in my last letter on the wire sieves. i hope to be able to send you on wednesday the printed account of my results, together with models of lamps which will burn and consume all explosive mixtures of the fire-damp. i have at last finished my enquiries with perfect satisfaction to myself, and i feel highly obliged to you for having called my attention to a subject where my labours will, i hope, be of some use. i am, my dear sir, very sincerely yours, h. davy. it is impossible to approach the consideration of this last, the most signal and splendid of his triumphs, without feelings of the highest satisfaction. he had already, as we have seen, disarmed the fire-damp of its terrors, it only remained for him to enlist it into his service. the simple means by which this was effected are as interesting as their results are important.[ ] [ ] "an account of an invention for giving light in explosive mixtures of fire-damp in coal mines, by consuming the fire-damp." read before the royal society, jan. , . davy had previously arrived at the fact, that wire-gauze might be substituted as air-feeders to the lamp, in the place of his tubes or safety canals; but not until after the lapse of several weeks, did the happy idea of constructing the lamp entirely of wire-gauze occur to him:--the history of this elaborate enquiry affords a striking proof of the inability of the human mind to apprehend simplicities, without a process of complication which works as the grappling machinery of truth. his original lamp with tubes or canals, as already described, was perfectly safe in the most explosive atmosphere, but its light was necessarily extinguished by it; whereas in the wire-gauze cage, the fire-damp itself continues to burn, and thus to afford to the miner a useful light, while he is equally secured from the fatal effects of explosion. [illustration] all then required for his guidance and protection in the darkness of the mine, are candles or lamps surrounded by small wire cages, which will at once supply air to the flame, and light to the miner; they may be obtained for a few pence, and be variously modified as circumstances may render necessary. the reader is here presented with a sketch of the gauze instrument, in its first and simplest form. the original lamp is preserved in the laboratory of the royal institution. nothing now remained but to ascertain the degree of fineness which the wire-gauze ought to possess, in order to form a secure barrier against the passage of flame. for this purpose, davy placed his lighted lamps in a glass receiver, through which there was a current of atmospherical air, and by means of a gasometer filled with coal gas, he made the current of air which passed into the lamp more or less explosive, and caused it to change rapidly or slowly at pleasure, so as to produce all possible varieties of inflammable and explosive mixtures; and he found that iron wire-gauze composed of wires from one-fortieth to one-sixtieth of an inch in diameter, and containing twenty-eight wires, or seven hundred and eighty-four apertures to the inch, was safe under all circumstances in atmospheres of this kind; and he consequently employed that material in guarding lamps for the coal mines, where, in january , they were immediately adopted, and have long been in general use. observations upon them in their working state, and upon the circumstances to which they are exposed, have led to a few improvements or alterations, merely connected with the modes of increasing light or diminishing heat, which were obvious from the original construction. [illustration] the annexed woodcut represents the lamp which is in present use. a is a cylinder of wire-gauze, with a double top, securely and carefully fastened, by doubling over, to the brass rim b, which screws on to the lamp c. the whole is protected by strong iron supports d, to which a ring is affixed for the convenience of carrying it. in a paper read before the royal society, on the rd of january , entitled, "some new experiments and observations on the combustion of gaseous mixtures, with an account of a method of preserving a continued light in mixtures of inflammable gases and air without flame," sir h. davy announces the application of a principle which he had discovered in the progress of his researches for increasing the utility of the safety-lamp, and which, a century ago, would have unquestionably exposed its author to the charge of witchcraft. having ascertained that the temperature of flame is infinitely higher than that necessary for the ignition of solid bodies, it appeared to him probable that, in certain combinations of gaseous bodies, although the increase of temperature might not be sufficient to render the gaseous matters themselves luminous, they might nevertheless be adequate to ignite solid matters exposed to them. during his experiments on this subject, he was led to the discovery of the curious phenomenon of slow combustion without flame. he observes, that there cannot be a better mode of illustrating the fact, than by an experiment on the vapour of ether or of alcohol. let a few coils of wire of platinum of the one-sixtieth or one-seventieth of an inch be heated by a hot poker or candle, and let it be brought into the glass; it will presently become glowing, almost white hot, and will continue so, as long as a sufficient quantity of vapour and of air remain in the glass.[ ] [ ] this principle has been applied for constructing what has been termed the _aphlogistic lamp_, which is formed by placing a small coil of platinum wire round the wick of a common spirit lamp. when the lamp, after being lighted for a few moments, is blown out, the platinum wire continues to glow for several hours, as long as there is a supply of spirit of wine, and to give light enough to read by; and sometimes the heat produced is sufficient to rekindle the lamp spontaneously. the same phenomena are produced by the vapour of camphor; and an aromatic fumigating lamp has lately been advertised for sale, which is no other than the contrivance above described; and it is evident that, if the spirit be impregnated with fragrant principles, an aromatic vinegar will be developed during its slow combustion, and diffused in fumes through the apartment. this experiment on the slow combustion of ether is accompanied with the formation of a peculiar acrid and volatile substance possessed of acid properties, which has been particularly examined by mr. daniell, who, having at first regarded it as a new acid, proposed for it the name of _lampic_ acid, in allusion to the researches which led to its discovery; he has, however, since ascertained that its acidity is owing to the acetic acid, which is combined with some compound of carbon and hydrogen, different both from ether and alcohol. the phenomena of slow combustion, as exhibited in certain states of the mine, by the safety-lamp, are highly curious and interesting. by suspending some coils of fine wire of platinum[ ] above the wick of his lamp, the miner will be supplied with light in mixtures of fire-damp no longer explosive; for should his flame be extinguished by the quantity of fire-damp, the little coil of platinum will begin to glow with a light sufficiently bright to guide him in what would otherwise be impenetrable darkness, and to lead him into a purer atmosphere, when the heat thus increased will very frequently be sufficient to rekindle his lamp! [ ] sir humphry davy attempted to produce the phenomena with various other metals, but he only succeeded with platinum and palladium; these bodies have low conducting powers, and small capacities for heat, in comparison with other metals, which seem to be the causes of their producing, continuing, and rendering sensible, these slow combustions. in this case it will be readily perceived, that the combustion of the fire-damp is continued so slowly, and at so low a temperature, as not to be adequate to that ignition of gaseous matter which constitutes flame, although it excites a temperature sufficient to render platinum wire luminous. sir humphry davy observes, that there never can be any danger with respect to respiration, whenever the wire continues ignited; for even this phenomenon ceases when the foul air forms about two-fifths of the volume of the atmosphere. the experiment, as originally performed by the illustrious chemist, is so interesting and instructive, that i shall here relate it in his own words. "i introduced into a wire-gauze safe lamp a small cage made of fine wire of platinum of one-seventieth of an inch in thickness, and fixed it by means of a thick wire of the same metal about two inches above the wick which was lighted. i placed the whole apparatus in a large receiver, in which, by means of a gas-holder, the air could be contaminated to any extent with coal gas. as soon as there was a slight admixture of coal gas, the platinum became ignited; the ignition continued to increase till the flame of the wick was extinguished, and till the whole cylinder became filled with flame; it then diminished. when the quantity of coal gas was increased, so as to extinguish the flame, at the moment of the extinction the cage of platinum became white hot, and presented a most brilliant light. by increasing the quantity of the coal gas still farther, the ignition of the platinum became less vivid: when its light was barely sensible, small quantities of air were admitted, its heat speedily increased; and by regulating the admission of coal gas and air, it again became white hot, and soon after lighted the flame in the cylinder, which as usual, by the addition of more atmospherical air, rekindled the flame of the wick." i have thus related, somewhat in detail, the history of a discovery, which, whether considered in relation to its scientific importance, or to its great practical value, must be regarded as one of the most splendid triumphs of human genius. it was the fruit of elaborate experiment and close induction; chance, or accident, which comes in for so large a share of the credit of human invention, has no claims to prefer upon this occasion; step by step, may he be followed throughout the whole progress of his research, and so obviously does the discovery of each new fact spring from those that preceded it, that we never for a moment lose sight of our philosopher, but keep pace with him during the whole of his curious enquiry. he commenced, as we have seen, with ascertaining the degree of combustibility of the fire-damp, and the limits in which the proportions of atmospheric air and carburetted hydrogen can be combined, so as to afford an explosive mixture. he was then led to examine the effects of the admixture of azote and carbonic acid gas; and the result of those experiments furnished him with the basis of his first plan of security. his next step was to enquire whether explosions of gas would pass through tubes; and on finding that this did not happen, if the tubes were of certain lengths and diameters, he proceeded to examine the limits of such conditions, and by shortening the tubes, diminishing their diameters, and multiplying their number, he at length arrived at the conclusion, that a simple tissue of wire-gauze afforded all the means of perfect security; and he constructed a lamp, which has been truly declared to be as marvellous in its operation, as the storied lamp of aladdin, realizing its fabled powers of conducting in safety, through "fiends of combustion," to the hidden treasures of the earth. we behold a power which, in its effects, seemed to emulate the violence of the volcano and the earthquake, at once restrained by an almost invisible and impalpable barrier of network--we behold, as it were, the dæmon of fire taken captive by science, and ministering to the convenience of the miner, while harmlessly fluttering in an iron cage. and yet, wonderful as the phenomenon may appear, his experiments and reasonings have demonstrated, that the interruption of flame by solid tissues permeable to light and air, depends upon no recondite or mysterious cause, but simply upon their cooling powers, which must always be proportional to the smallness of the mesh, and the mass of the metal. when it is remembered that the security thus conferred upon the labouring community, is not merely the privilege of the age in which the discovery was effected, but must be extended to future times, and continue to preserve human life as long as coal is dug from our mines, can there be found in the whole compass of art or science, an invention more useful and glorious? the wire-gauze lamp has now been several years extensively used in the mines, and the most satisfactory and unequivocal testimonies have been published of the complete security which it affords. they have amongst the miners obtained the name of _davys_; and such is the confidence of the work men in their efficacy, that by their aid they enter the most explosive atmospheres, and explore the most remote caverns, without the least dread of their old enemy the _fire-damp_. into the mines of foreign countries the safety-lamp has been introduced with similar success; and the illustrious discoverer has been repeatedly gratified by accounts of the enthusiasm with which his invention has been adopted in various parts of europe.[ ] [ ] a pamphlet appeared at mons, in the year , on the explosions that occur in coal mines, and on the means of preventing them by davy's safety-lamp. it was published under the direction of the chamber of commerce and manufactures of mons, accompanied by notes, and by the results of a series of experiments that had been conducted by m. gossart, president of the chamber. the province of hainault is said to be richer in coal mines than any other part of the continent of europe, and to have no less than one hundred thousand persons employed in the working them. the same kind of dangerous accidents occurred in these mines as in those of the north of england, and various expedients had been adopted for their prevention, which, however, availed but little in obviating them. "all the precautions," observe the reporters, "which had been hitherto known or practised, had not been able to preserve the unfortunate miners from the terrible effects of explosion. it is therefore an inappreciable benefit which we confer by making known the equally simple and infallible method of preventing these accidents, which has been discovered by the celebrated humphry davy." m. gossart gives an ample and accurate detail of the properties of the explosive gas, and confirms the truth of davy's experiments, by which the high temperature necessary for its inflammation, and the consequent means of preventing it, by reducing that temperature, as effected during its passage through wire-gauze, are clearly demonstrated. the lamp appears from this report to have been as useful in the mines of flanders as in those of england. the pamphlet is a valuable document, inasmuch as it affords an independent proof of the security of the instrument, and displays the high sense of obligation which foreign nations entertain to sir humphry davy for his invention. nor is the utility of this invention limited to the operations of mining. in gas manufactories, spirit warehouses,[ ] or druggists' laboratories, and in various other situations, where the existence of an explosive atmosphere[ ] may expose persons to danger, the safety-lamp may be advantageously used; and as science proceeds in multiplying the resources of art, this instrument will no doubt be found capable of many new applications. [ ] the danger of carrying a naked light into an atmosphere impregnated with the fumes of spirit was awfully exemplified by the loss of the kent east indiaman, by fire, in the bay of biscay, on the st of march . [ ] in cases where there is any suspicion of accumulations of carburetted hydrogen from the leakage of gas pipes, or from other sources, the safety-lamp should always be employed. a terrible accident occurred some years since at woolwich, from a room filled with the vapour of coal-tar, for the purpose of drying and seasoning timber intended for ship-building. as the combustion arose from the flame issuing through the flue, which ran along the apartment, at the moment the damper was applied at the top of the building, it is evident that, had a wire-gauze guard been used, the accident could not have occurred. the house was completely demolished, and nine persons were unfortunately killed. by the permission of the president and council of the royal society, several accounts of these researches, and of the invention and use of the safety-lamp were printed, and circulated through the coal districts. it might have been fairly expected that, in a district which had been so continually and so awfully visited by explosions, against which no human foresight had as yet been able to provide a remedy, the disinterested services of the greatest chemist of the age would at least have been received without a dissentient voice, and that his invention of security would have escaped the common fate of all great discoveries, and been accepted with every homage of respect and gratitude; but the inventor of the safety-lamp was doomed to encounter a bitter hostility from persons whom a spirit of rivalry, or a feeling of hopeless emulation, had cemented into a faction. from the period of the first announcement of the safety-lamp, a prejudice against its use was industriously circulated amongst the miners; and some persons even maintained the monstrous proposition, that any protection against the explosions of fire-damp would injure more than it could serve the collier, by inducing him to resume abandoned works, and thus continually to inhale a noxious atmosphere. the utility of the lamp having been established, in spite of every opposition, the claims of sir h. davy to its invention were next publicly challenged. it will hereafter be scarcely believed that an invention so eminently philosophic, and which could never have been derived but from the sterling treasury of science, should have been claimed in behalf of an engine-wright of killingworth, of the name of stephenson--a person not even professing a knowledge of the elements of chemistry. as the controversy to which this claim gave birth has long since subsided, i would willingly have treated it as a passing cloud, had not its shadow remained. the circumstances, however, of the transaction stand recorded in the magazines of the day, and the biographer of davy would compromise his rights, by omitting to notice the attempts that have been made to invalidate them. the claims which were made for the priority of mr. stephenson's invention of the safety-lamp were urged in several communications in the newcastle courant. it has been said in reply, that if dates were taken as evidence, not merely of priority, but of originality of invention, it must follow that mr. stephenson's lamp was derived from that of sir h. davy. with regard to the first of stephenson's lamps, the only one upon which the shadow even of a claim can be founded, it is unnecessary for the friends of truth to adopt such a line of defence; indeed, after a deliberate examination of all that has been published on the subject, i am very willing to believe that mr. stephenson did construct the lamp which dates its origin from the st of october , without any previous knowledge of the conclusions at which davy had arrived; for it was first announced to the coal-trade by mr. r. lambert on the rd of november, to the very meeting at which sir h. davy's private letter was inadvertently read.--but what were the principles, and what the construction of this lamp? it would appear that mr. stephenson had entertained some vague notion of the practicability of consuming the fire-damp as fast as it entered the lamp, and that if admitted only in small quantities, it would not explode the surrounding atmosphere: for effecting this object, he constructed a lamp with an orifice, over which was placed a slide, by the movement of which the opening could be enlarged, or diminished, and the volume of fire-damp to be admitted into the lamp regulated according to circumstances. now such a lamp could be nothing else than an exploding lamp; for to make it burn in common air, the orifice must have been so wide that, on going into an explosive atmosphere, the combustion in the interior could not have failed to pass it, and to have exploded the mine. here then is a _safety_-lamp, which as long as it is safe, will not burn, and the moment it begins to burn, it becomes unsafe! the testimonies in favour of the security afforded by this lamp were evidently procured from persons who were not only ignorant of the principles of its construction, but of the methods to be pursued for ascertaining its safety. i am surely justified in such a statement, when, instead of an _explosive mixture_, i find them throwing in _pure fire-damp_, which will always extinguish flame, whether burning in a safe or unsafe lamp. the importance and utility of davy's lamp having been completely established by the severest ordeals, the general gratitude of the country began more publicly to display itself, and a very strong feeling prevailed, that some tribute of respect should be paid to its inventor; in accordance with which, a deputation of the coal-owners of the rivers tyne and wear, and of the ports of hartley and blyth, requested the honour of an interview with sir h. davy; upon which occasion they presented him with the following letter, containing an expression of the thanks of the coal-owners. to sir humphry davy, ll.d. &c. newcastle, march , . sir, as chairman of the general meeting of proprietors of coal-mines upon the rivers tyne and wear, held in the assembly-rooms at newcastle, on the th instant, i was requested to express to you their united thanks and approbation for the great and important discovery of your safety-lamp for exploring mines charged with inflammable gas, which they consider admirably calculated to obviate those dreadful calamities, and the lamentable sacrifice of human life, which of late years have so frequently occurred in the mines of this country. they are most powerfully impressed with admiration and gratitude towards the splendid talents and brilliant acquirements that have achieved so momentous and important a discovery, unparalleled in the history of mining, and not surpassed by any discovery of the present age; and they hope that, whilst the tribute of applause and glory is showered down upon those who invent the weapons of destruction, this great and unrivalled discovery for preserving the lives of our fellow-creatures, will be rewarded by some mark of national distinction and honour. i am, sir, your most obedient humble servant, george waldie, chairman. a plan, however, was under consideration for recording the admiration and gratitude of the coal-owners, by a more permanent and solid memorial. the nature of this proposition will be best disclosed by inserting the following letter from mr. buddle. to the rev. dr. gray. wall's-end colliery, august , . sir, as i know that you feel much interest in all matters relating to sir h. davy's safety-lamp, i trust you will excuse the liberty i take in informing you, that the committee of the tyne, approving highly of the suggestion, that some mark of acknowledgment and respect should be presented to sir humphry by the coal-trade of this country, for the happy invention of his lamp, have convened a general meeting of coal-owners, to be holden at my office in newcastle, on saturday next the st instant, at twelve o'clock, to take the subject into consideration. i should have sooner informed you of this proposed meeting, had i not been detained in cumberland until yesterday; but i shall have the pleasure of transmitting to you a copy of its resolutions. i am sure that you will be gratified to learn that the lamps continue to go on as well as possible. we now have twelve dozen of them in daily use at this place. i have the pleasure to remain, with the greatest respect, sir, your most obedient humble servant, john buddle. to the same. newcastle, september , . sir, i now have the pleasure of sending you a copy of the resolutions of the general meeting of coal-owners on the st instant, and shall take the liberty of informing you of the future progress of this affair. sir humphry did me the honour yesterday to accompany me through the workings of a coal-pit at wall's-end, when i had an opportunity of witnessing several interesting experiments on his safety-lamp; and i have the satisfaction to add, that i believe he has now advanced it to the highest degree of perfection. i am, respectfully, sir, your humble servant, john buddle. the satisfactory result of this visit sir humphry communicated to mr. lambton, now lord durham; and i shall take this opportunity to state, that for this as well as for several other letters i shall hereafter have occasion to introduce, i am indebted to that noble lord, through the kind application of my friend sir cuthbert sharp. to j. g. lambton, esq. m.p. newcastle, september , . my dear sir, since i last had the pleasure of seeing you, i have examined the workings in the wall's-end collieries by the lamps, and have tried them in various explosive mixtures. on sunday, i went with mr. buddle to your _blower_, with the single lamps furnished with small tin reflectors. this simple modification rendered them perfectly safe, even in the furious _blow-pipe_, and at the same time increased their light. nothing could be more satisfactory than all the trials. i have left a paper in the hands of the rev. j. hodgson, which will be printed in a day or two; and i have desired him to send you ten copies, or as many more as you may like to have. i trust i have now left nothing undone as to the perfect security of the lamps, under every possible circumstance. i feel highly gratified that it was at your mines i effected the only object that remained to be accomplished--that of guarding against _blowers_ meeting fresh currents of air. i thank you very sincerely for the interest you have taken in the lamps, connected with my efforts to render them applicable in all cases. i remain, &c. h. davy. on the th of october , a letter appeared in the durham county advertiser, dated "gosforth, august nd, ," in the name of mr. w. brandling, in which, alluding to the resolutions of the coal-owners of the st of august, he expresses a wish that a strict examination should take place previous to the adoption of a measure which might convey a decided opinion to the public, as to the person to whom the invaluable discovery of the safety-lamp is actually due. "the conviction," says he, "upon my mind is, that mr. george stephenson, of killingworth colliery, is the person who first discovered and applied the principle upon which safe lamps may be constructed; for, whether the hydrogen gas is admitted through capillary tubes, or through the apertures of wire-gauze, which may be considered as merely the orifices of capillary tubes, does not, as i conceive, in the least affect the principle. "in the communications i have seen from sir h. davy, no dates are mentioned; and it is by a reference to them only that the question can be fairly decided. for the information of the meeting, therefore, i shall take the liberty of enclosing some which i received from mr. stephenson, to the correctness of which, as far as i am concerned, i can bear testimony; at the same time i beg leave to add, that the principle of admitting hydrogen gas in such small detached portions that it would be consumed by combustion,[ ] was, i understand, stated by him to several gentlemen, as the idea he had embraced two months before his lamp was originally constructed." [ ] granted:--but what connexion has that with the principle of davy's lamp, or with any _safety_ lamp? mr. brandling then proceeds to state, that the killingworth lamp, with a tube to admit the air, and a slide at the bottom of such tube to regulate the quantity to be admitted, was first tried in the killingworth pits on saturday october the st, ; but not being found to burn well, another was ordered the same day with three capillary tubes to admit the air; and on being tried in the mine on the th of november following, was found to burn better and to be perfectly _safe_.[ ] on the th of november, it was _tried_[ ] at killingworth office with inflammable air before richard lambert, esq.; and on the th of the same month, before c. j. brandling, esq. and mr. murray. [ ] it could not have been safe. [ ] "tried"--but how was it tried?--by forcing in _pure_ fire-damp, which will extinguish any lamp, instead of exposing the flame to an explosive mixture, which could alone furnish any test of its security. "on the th of november," he says, "a lamp was tried in the mine, in which the air was admitted by means of a double row of small perforations, and found to be perfectly safe, and to burn extremely well."[ ] [ ] very likely: but the reader will please to recollect, that sir h. davy had, before this, published an account of his principle of safety by systems of tubes or canals. at an adjourned meeting of the coal-owners, held on the th of october , j. g. lambton, esq. m.p. in the chair; mr. william brandling moved--"that the meeting do adjourn, until, by a comparison of dates, it shall be ascertained whether the merit of the safety-lamp belongs to sir humphry davy or to mr. george stephenson." on the question being put thereon, the same passed in the negative. a great number of the coal-owners, instead of pursuing the idea which had at first been suggested, of a general contribution on the vend, immediately commenced a subscription of individual proprietors of coal-mines; a measure which, it was thought, would express more distinctly and unequivocally the opinion of the trade as to the merit of the invention. the plan is developed in the following letter. to the reverend dr. gray. wall's-end colliery, october , . sir, it is the anxious wish of almost every individual in the trade to compliment sir humphry davy, in that way which may be most grateful to his feelings. it has been suggested that the object will be best attained by substituting an individual (colliery) subscription, instead of the proposed contribution on the vend; and it will at the same time show more distinctly the real opinion of the trade as to the merit of the invention. this idea was not suggested till yesterday afternoon, and of course there has been but little time to communicate it to the several coal-owners; but _all_ who have heard of the plan approve of it. to facilitate the business, the committee have formed the annexed scale of contribution.[ ] * * * * * i trust, sir, you will excuse the trouble which i have given you on this subject; but i am aware that you must feel interested in it; and i hope, sir, you will allow me to add, that i am fully sensible of the obligation which the coal trade is under to yourself, for having drawn sir h. davy's attention to that particular line of investigation, which has led to the important discovery of the safety-lamp. i am, sir, with the greatest respect, your most obedient humble servant, john buddle. [ ] i have not thought it necessary to enumerate the various sums which the different mines were called upon to contribute. some slight alterations were afterwards made in this scheme, in consequence of a wish having been expressed that the bishop of durham and the duke of northumberland should take the lead in a subscription. the following letter conveys some farther information upon this subject. to the reverend dr. gray. newcastle, january , . sir, i have to acknowledge the receipt of your letter of the th instant, communicating the intention of the reverend the dean and chapter of durham, to subscribe fifty guineas towards the plate to be presented to sir h. davy, which, together with two hundred guineas from the coal-owners of the wear, makes the subscription amount to nearly £ , and i shall expect some farther subscriptions. i am sure it will afford you satisfaction to learn that the lamps still continue to give the most gratifying proofs of the advantages resulting from their invention, and that not a single inch of human skin has been lost by fire, wherever they have been used. sir humphry has just made another important improvement in the lamp, by constructing the cylinder of _twisted_ wire-gauze. lamps thus constructed, possess the singular property of not becoming red-hot, under any circumstances of exposure to explosive mixtures, whether urged by a blast, or in a state of rest. i am with great respect, sir, your most obedient humble servant, john buddle. it may be collected from the following letter, that the committee, in announcing to sir h. davy the intended present of plate, delicately sounded him as to the form in which it would be most agreeable to him. to n. clayton, esq. grosvenor street, march , . sir, on my return to town, after an absence of some days, i found the letter of march the th, with which you honoured me, at the royal institution. i shall not lose a moment in replying to it, and in expressing my grateful feelings for the very flattering communication it contains. the gentlemen interested in the coal-mines of the two rivers tyne and wear, cannot offer me any testimony of their kindness, which i shall not receive with infinite pleasure. i hardly know how to explain myself on the particular subject of your letter; but as the committee express themselves satisfied as to the utility of the safety-lamp, i can only desire that their present, as it is highly honourable to me, should be likewise useful to my friends, and a small social circle, which it would be as a dinner-service for ten or twelve persons. i wish that even the plate from which i eat should awaken my remembrance of their liberality, and put me in mind of an event which marks one of the happiest periods of my life. i cannot find any language sufficiently strong to express my thanks to the gentlemen for the manner in which they have distinguished my exertions in their cause, and in the cause of humanity. i have the honour to remain, &c. h. davy. to revert once again to the faction--for such i must denominate it--which, in opposition to the most unequivocal evidence, continued to support the unjust claims of mr. stephenson; it would appear from various letters in my possession, that the feelings of davy were greatly exasperated by this ungenerous conduct. i shall introduce one of these letters, playful in the midst of its wrath, addressed to mr. lambton, the friend[ ] of his youth, and the manly and kind supporter of his scientific character, in the hour of persecution. [ ] it will be remembered that they resided together in the house of dr. beddoes. see page , vol. i. of these memoirs. in the library at lambton, there is a goodportrait of sir humphry. to j. g. lambton, esq. m.p. queen square, bath, oct. , . my dear sir, the severe indisposition of my wife has altered my plans. your letter slowly followed me here. mr. ---- is one of the persons who, after i had advanced a principle of security for a lamp, came upon the ground to endeavour to jockey me. i was not looking to a prize, i merely came forward to show an animal, the breed of which might be useful, when mr.----, dr.----, &c. brought their sorry jades, which had never before been seen or heard of, to kick at my blood mare. i never heard a word of george stephenson and his lamps till six weeks after my principle of security had been published; and the general impression of the scientific men in london, which is confirmed by what i heard at newcastle, is, that stephenson had some loose idea floating in his mind, which he had unsuccessfully attempted to put in practice till after my labours were made known;--then, he made something like a safe lamp, except that it is not _safe_, for the apertures below are four times, and those above, twenty times too large; but, even if stephenson's plans had not been posterior to my principles, still there is no analogy between his glass exploding machine, and my metallic tissue, permeable to light and air, and impermeable to flame. i am very glad that you attended the meeting; your conduct at no very distant period will be contrasted with that of some great coal-proprietors, who find reasons for their indifference, as to a benefit conferred upon them, in insinuations respecting the claims of dr. clanny, mr. stephenson, and others. where men resolve to be ungrateful, it is natural that they should be illiberal; and illiberality often hardens into malignity. i shall receive any present of plate under your auspices, and those of the committee over which you preside, with peculiar satisfaction. it will prove to me that my labours have not been disregarded by men of whose good opinion i am proud. i hope you will not blame me for not taking any notice of the attacks of my enemies in the north. i have no desire to go out of my way to crush gnats that buzz at a distance, and do not bite me, or to quarrel with persons who shoot arrows at the moon, and believe, because they have for an instant intercepted a portion of her light, that they have hit their mark. i am sensible to the circumstances under which you attended the meeting. i offer you my sincere congratulations, and ardent wishes that you may enjoy all possible happiness. believe me, &c. h. davy. on the th of september , sir humphry davy being expected to pass through newcastle on his return from scotland, preparations were made, and notice given of a dinner which it was proposed should take place on the th instant, for the purpose of presenting to the illustrious philosopher the service of plate which had been prepared for his acceptance. upon this gratifying occasion, a very large party assembled at the queen's head, consisting of a numerous and respectable body of coal-owners, and such other gentlemen as had interested themselves during the progress of the investigation, or taken an active part in promoting the introduction of the lamp into the mines. after the dinner had concluded, and certain toasts of form had been drunk, mr. lambton, who filled the chair on the occasion, rose, and on presenting the service of plate to the illustrious guest, addressed him, in a tone of great animation and feeling, in nearly the following terms: "sir humphry,--it now becomes my duty to fulfill the object of the meeting, in presenting to you this service of plate, from the coal-owners of the tyne and wear, as a testimony of their gratitude for the services you have rendered to them and to humanity. "your brilliant genius, which has been so long employed in an unparalleled manner, in extending the boundaries of chemical knowledge, never accomplished a higher object, nor obtained a nobler triumph. "you had to contend with an element of destruction which seemed uncontrollable by human power; which not only rendered the property of the coal-owner insecure, but kept him in perpetual alarm for the safety of the intrepid miner in his service, and often exhibited to him the most appalling scenes of death, and heart-sickening misery. "you have increased the value of an important branch of productive industry; and, what is of infinitely greater importance, you have contributed to the lives and persons of multitudes of your fellow-creatures. "it is now nearly two years that your safety-lamp has been used by hundreds of miners in the most dangerous recesses of the earth, and under the most trying circumstances. not a single failure has occurred--its absolute security is demonstrated. i have, indeed, deeply to lament more than one catastrophe, produced by fool-hardiness and ignorance, in neglecting to use the safeguard you have supplied; but these dreadful accidents even, if possible, exalt its importance. "if your fame had needed any thing to make it immortal, this discovery alone would have carried it down to future ages, and connected it with benefits and blessings. "receive, sir humphry, this permanent memorial of our profound respect and high admiration--a testimony, we trust, equally honourable to you and to us. we hope you will have as much pleasure in receiving, as we feel in offering it. long may you live to use it--long may you live to pursue your splendid career of scientific discovery, and to give new claims to the gratitude and praise of the world!" sir humphry having received the plate, replied as follows: "gentlemen,--i feel it impossible to reply, in an appropriate manner, to the very eloquent and flattering address of your distinguished chairman. eloquence, or even accuracy of language, is incompatible with strong feeling; and on an occasion like the present, you will give me credit for no small degree of emotion. "i have been informed that my labours have been useful to an important branch of human industry connected with our arts, our manufactures, commerce, and national wealth. to learn this from such practical authority is the highest gratification to a person whose ardent desire has always been to apply science to purposes of utility. "it has been also stated, that the invention which you are this day so highly honouring, has been subservient to the preservation of the lives and persons of a most useful and laborious class of men: this, coming from your own knowledge, founded upon such ample experience, affords me a pleasure still more exalted--for the highest ambition of my life has been to deserve the name of a friend to humanity. "to crown all, you have, as it were, embodied these sentiments in a permanent and magnificent memorial of your good opinion. i can make only imperfect and inadequate efforts to thank you. "under all circumstances of my future life, the recollection of this day will warm my heart; and this noble expression of your kindness will awaken my gratitude to the latest moment of my existence." sir humphry having sat down, and the cheering of the company subsided, the chairman proposed the health of the illustrious chemist, in three times three. "gentlemen," said sir humphry, "i am overpowered by these reiterated proofs of your approbation. you have overrated my merits. my success in your cause must be attributed to my having followed the path of experiment and induction discovered by philosophers who have preceded me: willingly would i divide your plaudits with other men of science, and claim much for the general glory of scientific discovery in a long course of ages. "gentlemen, i might dwell at some length upon the great increase of wealth and power to the country, within the last half century, by scientific invention, which never could have existed without coal-mines:--i shall refer only to the improvement in the potteries, to the steam-engine, and to the discovery of the gas lights. "what an immense impulse has the steam-engine given to the arts and manufactures! how much has it diminished labour, and increased the real strength of the country, far beyond a mere increase of population! by giving facilities to a number of other inventions, it has produced even a moral effect in rendering capital necessary for the perfection of labour, credit essential to capital, and ingenuity and mental energy a secure and dignified species of property. "science, gentlemen, is of infinitely more importance to a state than may at first sight appear possible; for no source of wealth and power can be entirely independent of it; and no class of men are so well able to appreciate its advantages as that to which i am now addressing myself. you have not only derived from it the means of raising your subterraneous wealth, but those also of rendering it available to the public. "science alone has made pit-coal such an instrument in the hands of the chemist and mechanic; it has made the elements of fire and water perform operations which formerly demanded human labour, and it has converted the productions of the earth into a thousand new forms of use and beauty. "gentlemen, allow me to observe, in conclusion, that it was in pursuing those methods of analogy and experiment, by which mystery had become science, that i was fortunately led to the invention of the safety-lamp. the whole progress of my researches has been registered in the transactions of the royal society, in papers which that illustrious body has honoured by their biennial medal;[ ] in which i can conscientiously assert, that i have gratefully acknowledged even the slightest hints or offers of assistance which i have received during their composition. [ ] the rumford medal, to be hereafter noticed. "i state this, gentlemen, not from vain-glory, but on account of certain calumnious insinuations which have arisen--not in the scientific world, for to that the whole progress of my researches is well known, but in a colliery. i must ever treat these insinuations with contempt; and after the honest indignation which has been expressed against them by the coal-owners in general, i cannot feel any anxiety on the subject, nor should i have referred to it at all, did i not believe that the very persons amongst whom these insinuations originated, were extensively benefited by, and were constantly using the invention they would seek to disparage. i could never have expected that such persons would have engaged their respectable connexions in mean attempts to impeach the originality of a discovery, given to them in the most disinterested manner, and for which no return was required but an honest acknowledgment of the benefit, founded upon truth and justice. "i do not envy them their feelings, particularly at the present moment: i do not wish to enquire into their motives: i do hope, however, that their conduct has been prompted by ignorance rather than by malevolence, by misapprehension rather than by ingratitude. "it was a new circumstance to me, that attempts to preserve human life, and to prevent human misery, should create hostile feelings in persons who professed to have similar objects in view. "gentlemen, i have had some opposition, much labour, and more anxiety, during the course of these researches; but had the opposition, the labour, and the anxiety been a thousand times as great, the events of this day would have been more than a compensation." sir humphry, after drinking the health and happiness of the company, proposed as a sentiment--"prosperity to the coal-trade." the healths of the duke of northumberland, the bishop of durham, and the reverend dr. gray, were drunk in succession. at ten o'clock, sir humphry, accompanied by the chairman, retired amidst the enthusiastic plaudits of a meeting, the object of which being one of convivial benevolence, the effect was that of unclouded hilarity. the party which had supported the claims of mr. stephenson had also their meeting; and it was held on the st of november. at this meeting it was resolved, "that it was the opinion of the persons present, that mr. g. stephenson having discovered the fact, that explosions of hydrogen gas will not pass through tubes and apertures of small dimensions, and having been the first to apply the principle to the construction of a safety-lamp, is entitled to some reward." a committee was accordingly formed to carry this resolution into effect, at the head of which was placed the name of the earl of strathmore. the respectable body of coal-owners, under whose auspices the invention of sir humphry davy had been introduced and rewarded, felt that they owed it to their own characters to repel assertions which amounted to a charge against themselves of ingratitude and injustice: a general meeting was accordingly summoned, at the assembly-rooms in newcastle, on the th of november , j. g. lambton, esq. m.p. in the chair--when it was resolved, "that the resolutions passed at the meeting of the friends of mr. g. stephenson on the th instant, impugn the justice and propriety of the proceedings of a meeting of the coal-trade on the st of august : "that the present meeting, therefore, feel themselves called upon, as an act of justice to the character of their great and disinterested benefactor, sir humphry davy, and as a proof that the coal-trade of the north in no way sanctions the resolutions of mr. stephenson's friends, to state their decided conviction, that the merit of having discovered the fact, that explosions of fire-damp will not pass through tubes and apertures of small dimensions, and of having applied that principle to the construction of a safety-lamp, _belongs to sir humphry davy alone_. "that this meeting is also decidedly of opinion, from the evidence produced in various publications by mr. george stephenson and his friends, subsequently to the meeting of the coal-trade which was held on the th of march , as well as from the documents which have been read at this meeting, that mr. stephenson _did not_ discover the fact, that explosions of fire-damp will not pass through tubes and apertures of small dimensions; and that he _did not_ apply that principle to the construction of a safety-lamp; and that the latest lamps made by mr. stephenson are evident imitations of those of sir humphry davy, and that, even with that advantage, they are so imperfectly constructed as to be actually unsafe. "that the above resolutions be published thrice in the newcastle papers, and in the courier, morning chronicle, and edinburgh courant; and that printed copies thereof be sent to the lords lieutenants of the two counties, to the lord bishop of durham, and to the principal owners and lessors of collieries upon the tyne and wear." the following letter from sir humphry davy announces the farther measures which he also had thought proper to pursue, in order to counteract the impression which the meeting of mr. stephenson's friends might have produced on the less informed part of the public. to j. g. lambton, esq. m.p. november , . my dear sir, i shall send off by this post a copy of the resolutions, which will appear to-morrow in the chronicle and courier. the men of science who have signed these resolutions are the first chemists and natural philosophers of the country, with the president of the royal society, the most illustrious body in europe, at their head. it is disagreeable to be thus obliged to use artillery for the destruction of bats and owls; but it was necessary that something should be done. the messrs. ---- have for a long time been endeavouring to destroy my peace of mind; my offence being that of conferring a benefit. the only persons i knew in newcastle, before i gave the safety-lamp to the coal-owners, were dr. headlam and mr. bigge, so that friends i had none; and the few persons with whom i had a slight acquaintance, and who were civil to me before i discovered the safety-lamp, became my enemies. it requires a deep metaphysician to explain this--can it be that i did not make them the medium of communication to the colliers?--but i quit a subject to which i have no desire to return, and shall only recollect that day when your eloquence touched my feelings more than it flattered my self-love. believe me, &c. &c. h. davy. the following are the resolutions of a meeting adverted to in the preceding letter, and which was held "for considering the facts relating to the discovery of the lamp of safety." soho square, nov. , . "an advertisement having been inserted in the newcastle courant, of saturday, november , , purporting to contain the resolutions of 'a meeting held for the purpose of remunerating mr. george stephenson, for the valuable service he has rendered mankind by the invention of his safety-lamp, which is calculated for the preservation of human life in situations of the greatest danger,' "we have considered the evidence produced in various publications by mr. stephenson and his friends, in support of his claims; and having examined his lamps, and enquired into their effects in explosive mixtures, are clearly of opinion-- "first,--that mr. george stephenson _is not_ the author of the discovery of the fact, that an explosion of inflammable gas will not pass through tubes and apertures of small dimensions. "secondly,--that mr. george stephenson _was not_ the first to apply that principle to the construction of a safety-lamp, none of the lamps which he made in the year having been safe, and there being no evidence even of their having been made upon that principle. "thirdly,--that sir humphry davy not only discovered, independently of all others, and without any knowledge of the unpublished experiments of the late mr. tennant on flame, the principle of the non-communication of explosions through small apertures, but that he has also the sole merit of having first applied it to the very important purpose of a safety-lamp, which has evidently been imitated in the latest lamps of mr. george stephenson. (signed) "joseph banks, p.r.s. "william thomas brande, "charles hatchett, "william hyde wollaston." thus terminated a controversy, the discussion of which, i am well aware, many of my readers will consider as having been protracted to a tedious, and perhaps to an unnecessary extent; but the biographer had no alternative. in passing it by without a notice, he would have violated his faith to the public, have given a tacit acknowledgment of the claims of stephenson, and, in his judgment, have committed an act of gross injustice to the illustrious subject of his history; while by giving only an abridged statement, he would have furnished a pretext for doubt, and an opportunity for malevolence. it is due also to sir humphry davy to observe, that had he practised more reserve in the communication of his results, the spirit of rivalry would have expired without a struggle,--for it derived its only support and power from the generosity of its victim. had he secured for himself the advantages of his invention by patent, he might have realized wealth to almost any extent; but to barter the products of his intellectual exertions for pecuniary profit, was a course wholly at variance with every feeling of davy's mind; and we therefore find him, in the advancement, as at the commencement of his fleeting career, spurning the golden apples from his feet, and hastening to the goal for that prize which could alone reward all his labours--the meed of immortal fame. from a letter dated newcastle, august , which i had the pleasure to receive from mr. buddle, i extract the following interesting passage:-- "in the autumn of , sir humphry davy accompanied me into some of our fiery mines, to _prove_ the efficacy of his lamp. nothing could be more gratifying than the result of those experiments, as they inspired every body with perfect confidence in the security which his invention had afforded. "sir humphry was delighted, and i was overpowered with feelings of gratitude to that great genius which had produced it. "i felt, however, that he did not contemplate any pecuniary reward; and, in a private conversation, i remonstrated with him on the subject. i said, 'you might as well have secured this invention by a patent, and received your five or ten thousand a-year from it.' the reply of this great and noble-minded man was,--'no, my good friend, i never thought of such a thing; my sole object was to serve the cause of humanity; and, if i have succeeded, i am amply rewarded in the gratifying reflection of having done so.' i expostulated, saying, that his ideas were much too philosophic and refined for the occasion. he replied, 'i have enough for all my views and purposes; more wealth might be troublesome, and distract my attention from those pursuits in which i delight;--more wealth,' he added, 'could not increase either my fame or my happiness. it might, undoubtedly, enable me to put four horses to my carriage; but what would it avail me to have it said that sir humphry drives his carriage-and-four?'" the present bishop of bristol, to whom the world is so greatly indebted for having first called the attention of sir humphry davy to the subject of explosions from fire-damp, and who has kindly interested himself in my arduous and anxious undertaking, was desirous to obtain for me the latest accounts with respect to the safety-lamp, as to the constancy of its use, and the extent of its security; and his lordship informs me, that having applied to mr. buddle and mr. fenwick for information upon these points, their answers have been most satisfactory; at the same time, his lordship transmitted me much valuable information, which was accompanied by the following letter from mr. buddle. to the right reverend the lord bishop of bristol. wall's-end, august , . my lord, i have the honour to acknowledge the receipt of your lordship's letter of yesterday's date. i am glad your lordship has interested yourself in doctor paris's work, and i hope that he will be enabled, through the assistance of sir humphry's friends, to do ample justice to the genius and worth of that excellent man. i should be very happy if any letters of mine could assist dr. paris in doing justice to his merits in the invention of the safety-lamp; and i shall with pleasure submit to your lordship's better judgment and discretion the selection of such of them as may seem to be conducive to that object. i do not find that any improvement whatever has been made, either in the principle or construction of the _original lamp_, as presented to us by sir humphry. his transcendent genius seems to have anticipated every thing belonging to the subject, and has left nothing more to be done. i have the honour to be, my lord, with great respect, your lordship's most obedient, humble servant, john buddle. in consequence of some late reports of accidents in the mines, i requested my friend sir cuthbert sharp to make certain enquiries in the mining districts; and for this purpose, i sent him a string of queries, to which i begged him to obtain answers. these questions were submitted to mr. buddle, and they produced the following letter. to sir cuthbert sharp. newcastle, august , . my dear sir cuthbert, i return dr. paris's letter, and shall briefly answer his enquiries. if the davy lamp was exclusively used, and due care taken in its management, it is certain that few accidents would occur in our coal mines; but the exclusive use of the "_davy_" is not compatible with the working of many of our mines, in consequence of their not being workable without the aid of gunpowder. in such mines, where every collier must necessarily fire, on the average, two _shots_ a-day, we are exposed to the risk of explosion from the ignition of the gunpowder, even if no naked lights were used in carrying on the ordinary operations of the mine. this was the case in jarrow colliery, at the time the late accident happened. as the use of gunpowder was indispensable, naked lights were generally used, and the accident was occasioned by a '_bag_' of inflammable air forcing out a large block of coal, in the face of a drift, from a fissure in which it had been pent up, perhaps from the creation, and firing at the first naked light with which it came in contact, after having been diluted down to the combustible point by a due admixture of atmospheric air. as to the number of old collieries and old workings which have been renovated, and as to the quantity of coal which has been, and will be saved to the public by the invention of the "_davy_," it is scarcely possible to give an account, or to form an estimate. in this part of the country, 'walker's colliery,' after having been completely worked out, according to the former system, with candles and steel-mills, and after having been abandoned in , was reopened in by the aid of the "_davy_" and has been worked on an extensive scale ever since, and may continue to be worked for an almost indefinite period. great part of the formerly relinquished workings of wall's-end, willington, percy-main, hebburn, jarrow, elswick, benwell, &c. &c., as well as several collieries on the wear, have been recovered, and are continued in work by the invention of the "_davy_." if i had only what you know perfectly well i have not--time, i could write a volume on this subject. i shall shortly, through the medium of a friend, get an important paper on the subject of the "_davy_," put into dr. paris's hands. believe me, my dear sir cuthbert, to remain yours very faithfully, john buddle. the bishop of bristol has placed at my disposal a communication from mr. fenwick, a gentleman of much practical ability, which affords additional evidence of the utility of the lamp; from which the following is an extract. "sir h. davy's safety-lamp has afforded much security in the general working of mines, particularly by enabling the coal-owner to work, in several situations, the pillars of coal formerly left therein, which, under the system of working by candles, or open flame, was deemed hazardous and impracticable; and, in consequence, one-sixth part more of coal may be estimated as obtainable from those mines which are subject to hydrogen gas. also in the working of the pillars of coal, (commonly called the second working,) great advantages and securities, as well as saving of expenses, have resulted from the use of this lamp, not only to the lessees of collieries, inasmuch as more coal is obtained from a given space than before, (particularly in collieries subject to fire-damp,) but also to the lessor of such mines, by their being more productive, and of course more durable than heretofore. "another advantage results from the use of this safety-lamp, and in the working of the pillars in particular. it is found now, through experience, that the changeable state of the atmosphere, which our barometers daily indicate, has a most powerful effect on the noxious air in mines; as, from a sudden change in the atmosphere, indicated by the rapid fall of the mercury in the barometrical tube, a rapid discharge of noxious gas into the workings and excavations of the mine is the consequence, caused by the want of the atmospheric equilibrium:[ ] in which case the mine becomes suddenly surcharged with hydrogen, and if worked by the light of _open flame_, an explosion may take place before the possibility of such a circumstance can even be suspected; but if worked by the safety-lamp, it is only shown by the gas in the lamp becoming a pillar of harmless flame. this circumstance frequently takes place when any atmospheric change causes the mercury in the barometer to sink to twenty-eight inches and a half or thereabouts." [ ] this is a very interesting fact, and gives much support to the theory advanced at page of this volume. in the year , sir humphry davy had the honour to receive from the emperor alexander of russia, a superb silver gilt vase, standing in a circular tray enriched with medallions. on the cover was a figure, of about sixteen or eighteen inches in height, representing the god of fire, weeping over his extinguished torch. the circumstances under which this vase was presented have been communicated to me by mr. smirnove, secretary to the embassy. to j. a. paris, m.d. wigmore street, may , . dear sir, it was in the month of april, or may, , that the late sir humphry davy expressed to prince, then count, lieven, his wish to offer to the emperor of russia a model of his safety-lamp, which he had recently improved, accompanied by an explanatory pamphlet on the subject. prince lieven of course complied with this request; and the emperor having been pleased to accept it, ordered the ambassador, in november of the same year, to thank sir humphry for it in his majesty's name, and to assure him how much his majesty appreciated the merit of an invention, the double effect of which was to favour the progress of more than one branch of industry, and to ensure the safety of persons employed in the coal-mines, against those fatal accidents which had hitherto so frequently occurred. the ambassador, at the same time, delivered to sir humphry a silver-gilt vase,[ ] in the name of the emperor, in testimony of the high satisfaction with which that sovereign had been pleased to accept the object in question. i beg you to believe me, with regard and esteem, your faithful servant, john smirnove. [ ] of the value of about one hundred and eighty guineas. it is well known to the friends of davy, that in his conversation as well as in his correspondence, he always dwelt with peculiar satisfaction and delight upon the invention of his safety-lamp. mr. poole, in a letter lately addressed to me, observes--"how often have i heard him express the satisfaction which this discovery had given him. 'i value it,' said he, 'more than any thing i ever did. it was the result of a great deal of investigation and labour; but, if my directions be only attended to, it will save the lives of thousands of poor labourers. i was never more affected,' he added, 'than by a written address which i received from the working colliers, when i was in the north, thanking me, in behalf of themselves and their families, for the preservation of their lives.' i remember how delighted he was when he showed me the service of plate presented to him by those very men and their employers, as a testimony of their gratitude." the following letter evinces a similar feeling. to thomas poole, esq. queen's square, bath, oct. , . my dear poole, it is very long since any letters have passed between us. the affections and recollections of friendly intercourse are of a very adhesive nature; and i think you will not be displeased at being put in mind that there is an old friend not very far from you, who will be very glad to see you. bath does not suit me much, nor should i remain here, but my wife has been indisposed, and the waters seem to benefit her, and promise to render her permanent service, and if that happens, i shall be pleased even with this uninteresting city. i have seen many countries and nations since we met. * * * * * i have just come from the north of england, where it has pleased providence to make me an instrument for preserving the lives of some of my fellow-creatures. you, i know, are of that complexion of mind that the civic crown will please you more than even the victor's laurel wreath. i have a bed, though a small one, at your service; if you can come here for two or three days, i assure you we shall be most happy to see you. we shall remain in bath about three weeks. i shall be absent for a few days in the beginning of next week, and after that i shall be stationary till the middle of november. give me a few lines, and say when we may expect you. i am, my dear poole, very sincerely yours, h. davy. to the same. grosvenor street, dec. , . my dear poole, the late melancholy event[ ] has thrown a gloom over london, and indeed over england. the public feeling is highly creditable to the moral tone of the people. the loss of a princess, known only by good qualities, living in a pure and happy state of domestic peace, is in itself affecting; but when it is recollected that two generations of sovereigns of the first people in the world have been lost at the same moment, the event becomes almost an awful one. i go on always labouring in my vocation. i am now at work on a subject almost as interesting as the last which i undertook. it is too much to hope for the same success; at least i will deserve it. when you come to town in the spring, which i trust you will do, i shall show you my service of plate. i do not think you will like it the less for the cause of the gift. i am not sure whether i shall not take a run down to nether stowey and the west for a few days, if you encourage me with any hopes of the estate[ ] and of woodcocks. you will fix my plans. i shall be disengaged between the th and christmas, and shall like to revisit lymouth, and above all to shake you by the hand. lady d. is in better health than i have ever known her to possess. she begs her kind remembrances. i am, my dear poole, most affectionately yours, h. davy. [ ] the death of the princess charlotte. [ ] he here alludes to an estate in the neighbourhood of nether stowey, which he wished to purchase, and about which he had requested mr. poole to make enquiries. in a strictly scientific point of view, the most interesting results which have arisen out of the investigation for constructing a safety-lamp, are perhaps those which have made us better acquainted with the true nature of flame, and the circumstances by which it is modified; and which have led to some practical views connected with the useful arts. it is, i think, impossible to enter into the details of those curious investigations[ ] which, under the title of "some researches on flame," were communicated to the royal society, and read before that body on the th of january , without being forcibly struck with the address by which davy, in the first instance, brought abstract science to promote and extend practical knowledge; and then, as it were by a species of multiplied reflection, applied the new facts thus elicited for the farther extension of speculative truth; which in its wider range became again instrumental in disclosing a fresh store of useful facts. it may be said to have been the power of dexterously combining such methods which constituted the felicity of his genius; for, in general, each of them requires for its successful application a mind of quite a distinct order and construction. mr. babbage has very justly observed, that those intellectual qualifications which give birth to new principles or to new methods, are of quite a different order from those which are necessary for their practical application. davy furnished the exception that was necessary to make good the rule. [ ] a short notice of them first appeared in the third number of the "journal of science and the arts," edited at the royal institution. he detects, in the first instance, the general principle of inflammable gas, in a state of combustion, being arrested in its progress by capillary tubes; he next applies it to the construction of a safety-lamp, and then, by observing the phenomena which this lamp exhibits, is led to novel views respecting the nature and properties of flame.--i shall endeavour to offer a popular view of the curious and interesting truths disclosed by this latter research. he had observed that, when the coal gas burnt in the iron cage, its colour was pale, and its light feeble; whereas the fact is rendered familiar to us all by the flame of the gas lights, that in the open air carburetted hydrogen burns with great brilliancy. upon reflecting on the circumstances of the two species of combustion, he was led to believe that the cause of the superiority of the light in the latter case might be owing to a _decomposition_ of a part of the gas towards the interior of the flame, where the air was in the smallest quantity; and that the consequent deposition of charcoal might first by its _ignition_, and afterwards by its _combustion_, contribute to this increase of light. a conjecture which he immediately verified by experiment.[ ] [ ] this theory of davy is well illustrated by the change produced in the flame of gas-light, when acted upon by the wind, as may be seen during an illumination. the loss of light under these circumstances evidently arises from the more rapid combustion of the gas, by its more complete admixture with air; in consequence of which the decomposition above described does not take place. the intensity therefore of the light of flames depends principally upon the production and ignition of _solid_ matter in combustion, so that heat and light are in this process independent phenomena. these facts, davy observes, appear to admit of many applications; in explaining, for instance, the appearance of different flames--in suggesting the means of increasing or diminishing their light, and in deducing from their characters a knowledge of the composition of their constituent parts. the point of the inner blue flame of a candle or lamp urged by the blow-pipe, where the heat is the greatest and the light the least, is the point where the whole of the charcoal is burnt in its gaseous combinations, without previous ignition. the flames of phosphorus and of zinc in oxygen, and that of potassium in chlorine, afford examples of intensity of light depending upon the production of _fixed_ solid matter in combustion; while on the contrary, the feebleness of the light of those flames, in which gaseous and volatile matter is alone produced, is well illustrated by those of hydrogen and sulphur in oxygen, or by that of phosphorus in chlorine. from such facts, he is inclined to think that the luminous appearance of shooting stars and meteors cannot be owing to any inflammation of gas, but must depend upon the ignition of solid matter. dr. halley calculated the height of a meteor at ninety miles, and the great american meteor, which threw down showers of stones, was estimated at only seventeen miles high. the velocity of the motion of such bodies must in all cases be immensely great, and the heat thus produced by the compression of the most rarefied air, davy thinks, must be sufficient to ignite the mass; and that all the phenomena may be explained by assuming that _falling stars_ are small solid bodies moving round the earth in very eccentric orbits, which become ignited only when they pass with immense velocity through the upper regions of the atmosphere, and which, when they contain either combustible or elastic matter, throw out stones with explosion. by the application of such a principle did he also infer the composition of a body from the character of its flame: thus, says he, ether, during its combustion, would appear to indicate the presence of _olefiant gas_. alcohol burns with a flame similar to that of a mixture of carbonic oxide and hydrogen; so that the first is probably a binary compound of olefiant gas and water, and the second of carbonic oxide and hydrogen. when the proto-chloride of copper is introduced into the flame of a candle or lamp, it affords a peculiar dense and brilliant red light, tinged with green and blue towards the edges, which seems to depend upon the separation of the chlorine from the copper by the hydrogen, and the ignition and combustion of the solid copper and charcoal. the acknowledged fact of the brightest flames yielding the least heat is easily reconciled, when we learn that the light depends upon fixed matter which carries off the heat. it is equally obvious, that by art we may, for practical purposes, easily modify these phenomena. in the next place, having observed that wire-gauze cooled down flame beyond its combustible point, he was led to enquire into the nature of pure flame; and he readily demonstrated it to be _gaseous matter heated so highly as to be luminous_; and that the temperature necessary for such an effect was much greater than had been imagined, varying, however, in different cases. the flame of a common lamp he proved, by a very simple experiment, to exceed even the white heat of solid bodies, and which is easily shown by the simple fact of heating a piece of platinum wire over the chimney of an argand lamp fed with spirit of wine; when it will be seen that air, which is not of sufficient temperature to appear luminous, is still sufficiently hot to impart a white heat to a solid body immersed in it. the fact of different gaseous bodies requiring different degrees of heat to raise them into flame, was an inference immediately deducible from the phenomena of his _safety gauze_. a tissue of one hundred apertures to the square inch, made of wire of one-sixtieth, will, at common temperatures, intercept the flame of a spirit-lamp, but not that of hydrogen; and, when strongly heated, it will no longer arrest the flame of the spirit-lamp. a tissue which, when red-hot, will not interrupt the flame of hydrogen, will still intercept that of olefiant gas; and a heated tissue, which would communicate explosion from a mixture of olefiant gas and air, will stop an explosion of fire-damp. fortunately for the success of the safety-lamp, carburetted hydrogen requires so high a temperature to carry on its combustion, that even metal, when white-hot, is far below it; and hence red-hot gauze, in sufficient quantity, and of the proper degree of fineness, will abstract heat enough from the flame to extinguish it. the discovery of the high temperature which is necessary for the maintenance of flame, suggested to the philosopher the reason of its extinction under various circumstances. he considers, that the common operation of blowing out a candle principally depends upon the cooling power of the current of air projected into the flame;[ ] and he observes, that the hottest flames are those which are least easily blown out. he farther illustrated this subject by surrounding a very small flame with a ring of _metal_, which had the effect of cooling it so far as to extinguish it; but a ring of _glass_, of similar dimensions and diameter, being a less perfect conductor of heat, produced no such effect. [ ] _quere._ is this theory correct? may not the effect be mechanical, the appulse of the air separating the flame from the wick.--upon the principle suggested by davy, how are we to explain the fact of rekindling the flame by a blast? it had been long known that flame ceased to burn in highly rarefied air; but the degree of rarefaction necessary for this effect had been very differently stated. the cause of the phenomenon was generally supposed to depend upon a deficiency of oxygen. in the commencement of his enquiry into this subject, davy observed that the flame of hydrogen gas, the degree of rarefaction and the quantity of air being the same, burnt longer when it issued from a larger than a smaller jet,--a fact the very reverse of that which must have happened had the flame expired for want of oxygen; he moreover observed, that when the larger jet was used, the point of the glass tube became white-hot, and continued red-hot till the flame was extinguished: he therefore concluded, that the heat communicated to the gas by this tube was the cause of its protracted combustion, and that _flame expired in rarefied air, not for want of nourishment from oxygen, but for want of heat, and that if its temperature could be preserved by some supplementary aid, the flame might be kept burning_. the experiment by which he confirmed this theory was as beautiful as it was satisfactory. he burnt a piece of camphor in a _glass_ tube, under the receiver of an air-pump, so as to make the upper part of the tube red-hot; its inflammation was found to continue when the rarefaction was nine times; but by repeating the experiment in a _metallic_ tube, which could not be so considerably heated by it, it ceased after the rarefaction exceeded six times. it follows then that by artificially imparting heat,[ ] bodies may be made to burn in a rarefied air, when under other circumstances they would be extinguished. [ ] "it is upon this principle that, in the argand lamp, the liverpool lamp, and in the best fire-places, the increase of effect does not merely depend upon the rapid current of air, but likewise upon the heat preserved by the arrangement of the materials of the chimney, and communicated to the matters entering into inflammation." the art of making a good fire depends also upon the same principle of economising the heat. the following may be considered as an _experimentum crucis_, in proof of the fact that combustibility is neither increased nor diminished by rarefaction. he introduced the flame of hydrogen, in which was inserted a platinum wire, into a receiver of rarefied air, and he found that, as long as the metal remained at a dull red-heat, the flame continued to burn: now it so happens that the temperature, at which platinum approaches a red-heat, is precisely that at which hydrogen inflames under the ordinary pressure of the atmosphere; whence it follows, that its combustibility is not altered by rarefaction. the same law was found to apply to the flames of other bodies; those requiring the least heat for their combustion always sustaining the greater rarefaction without being extinguished.[ ] [ ] from a calculation of the ratio in which the density of the atmosphere decreases with its altitude, and from that of the relative combustibility of different bodies, it follows that the taper would be extinguished at a height of between nine and ten miles--hydrogen, between twelve and thirteen--and sulphur, between fifteen and sixteen. hitherto he had only considered the effects of rarefaction, when produced by the diminution of pressure; he had next to investigate the phenomena of rarefaction when occasioned by expansion from heat. the experiments of m. de grotthus had apparently shown that rarefaction by heat destroys the combustibility of gaseous mixtures; those of davy, however, proved that it enables them to explode at a lower temperature. in the progress of this research, while passing mixtures of hydrogen and oxygen through heated tubes, the heat being still below redness, he observed that steam was formed without any combustion. here was a slow combination without combustion, as long since observed with respect to hydrogen and chlorine, and oxygen and metals; and he believes that such a phenomenon will happen at certain temperatures with most substances that unite by heat. on trying charcoal, he found that at a temperature which appeared to be a little above the boiling point of quicksilver, it converted oxygen pretty rapidly into carbonic acid, without any luminous appearance, and that, at a dull red-heat, the elements of olefiant gas combined in a similar manner with oxygen, slowly and without explosion. it occurred to davy, in the progress of these experiments, that, during this species of slow combination, although the increase of temperature might not be sufficient to render the gaseous matters luminous, or to produce flame, it might still be adequate to ignite solid matters exposed to them. it was while engaged in devising experiments to ascertain this fact, that he was accidentally led to the discovery of the continued ignition of platinum wire, during the slow combination of coal gas with atmospheric air; the circumstances of which have been already related, as well as the curious invention to which the application of the fact gave origin.[ ] [ ] see page of this volume. for this and his preceding papers on the subjects of flame and combustion, the president and council of the royal society adjudged to sir humphry davy the gold and silver medals, on the donation of count rumford;[ ] and never, i will venture say, did a society in awarding a prize more faithfully comply with the intentions of its founder. [ ] at the anniversary of the royal society, november , count rumford transferred one thousand pounds, three per cent. consols, to the use of the society, on condition that a premium should be biennially awarded to the author of the most important discovery, or useful invention, made known in any part of europe during the preceding two years, on the subject of heat and light. in regard to the form in which this premium was to be conferred, he requested that it might always be given in two medals, struck in the same die, the one of gold, and the other of silver. should not any discovery or improvement be made during any terms of years, he directed that the value of the medals should be reserved, and being laid out in the purchase of additional stock, go in augmentation of the capital of this premium. medals upon this foundation have been successively voted to professor leslie, for his experiments on heat, published in his work entitled "an experimental enquiry into the nature and properties of heat;"--to mr. william murdoch, for his publication "on the employment of gas and coal for the purpose of illumination;"--to m. malus, for his discoveries of certain new properties of reflected light;--to dr. wells, for his essay on dew;--to sir humphry davy, as above stated;--to dr. brewster, for his optical investigations;--and, lastly, to mr. fresnel, for his optical researches. on the completion of these laborious enquiries, it was thought expedient to give a wider circulation to their results than the publication of them in the philosophical transactions was calculated to afford; and sir humphry davy was therefore induced to reprint his principal memoirs, so as to form an octavo volume,[ ] which might be accessible to the practical parts of the community. [ ] "on the safety-lamp for coal mines, with some researches on flame.--london, ." the enlightened friends of science very reasonably expected that a service of such importance to society as the invention of the safety-lamp, would have commanded the gratitude of the state, and obtained for its author a high parliamentary reward; nor were there wanting zealous and disinterested persons to urge the claims of the philosopher: but a government which had bestowed a splendid pension upon the contriver of an engine[ ] for the destruction of human life, refused to listen to any proposition for the reward of one who had invented a machine for its preservation. it is true that, in consideration of various scientific services, they tardily and inadequately acknowledged the claims of davy, by bestowing upon him the dignity of baronetcy[ ]--a reward, it must be confessed, that neither displayed any regard to his condition, nor implied the just estimate of his merits. the measure of value, however, enables us to judge of the standard by which the state rates the various services to society; and deeply is it to be lamented that the disproportioned exaltation of military achievement, crowned with the highest honours, depresses respect for science, and raises a false and fruitless object of ambition. [ ] sir william congreve, in addition to other marks of favour, received a pension of twelve hundred a-year, for the invention of his rocket; or, in the exact terms of the grant, "for inventions calculated to destroy or annoy the enemy." [ ] he was created a baronet on the th of october, . the passion for arms is a relict of barbarity derived from the feudal ages; the progress of civilization, and the cultivation of the mind, should have led us to prefer intellectual to physical superiority, and to recognise in the successes of science the chief titles to honour. this reversal of the objects of importance can never be redressed until the aristocracy shall be possessed of a competent share of scientific knowledge, and instructed to appreciate its value. to effect such a change, the system of education so blindly and obstinately continued in our great public schools, must be altered; for minds exclusively applied to classical pursuits, and trained to recognise no other objects of liberal study, are indisposed and indeed disqualified for enquiries ministering to the arts of life, and arrogantly despised for their very connexion with utility. it is in the early ignorance of the rudiments of science that the after negligence of science has its source. the instances in proof of the extent of the ignorance and indifference i have noted, and of their pernicious effects upon the most important interests of society, especially legislation, and the administration of justice, are abundant. in parliament, how is a question of science treated? in our courts of law, and criminal investigation, it is lamentable to observe the frequent defeat of justice, arising from erroneous conception, or from the utter absence of the requisite knowledge. in the ordinary affairs of life, we see conspicuous, amongst the dupes of quackery and imposture, those whose stations should imply the best instruction, and whose conduct, unfortunately, has the effect of example. a contempt far-spreading, and proceeding from the well-springs of truth, is rapidly rising against this exalted ignorance; the industrious classes of society are daily becoming more imbued with knowledge upon scientific subjects, and the nobility, if they would preserve their superiority in social consideration, must descend to the popular improvement. * * * * * before concluding the present chapter, i must carry back my history to the year , for the purpose of recording a circumstance in the life of davy, which, while it exemplifies his general love of science, evinces the local attachment he retained for the town of his birth. in the year , the geological society of cornwall was established at penzance. its objects are to cultivate the sciences of mineralogy and geology, in a district better calculated perhaps for such pursuits than any other spot in europe,--to register the new facts which are continually presenting themselves in the mines, and to place upon permanent record, the history of phenomena which had hitherto been entrusted to oral tradition; but, above all, its object was to bring science in alliance with art; to prevent the accidents which had so frequently occurred from explosion in the operation of blasting rocks; and, in short, to render all the resources of speculative truth subservient to the ends of practical improvement. no sooner had the establishment of so useful an institution been communicated to davy, than he testified his zeal for its welfare by a handsome donation to its funds; which was followed by a present of a very extensive suite of specimens, illustrative of the volcanic district of naples, and which had been collected by himself. he also afterwards communicated to the society a memoir on the geology of cornwall, which has been published in the first volume of its transactions. in this paper, he discusses several of the more difficult questions connected with the origin of veins. he first observed the granitic veins, which have called forth so much attention from geologists, about the year ; probably before they had excited much scientific notice: he is disposed to regard them as peculiar to the low metalliferous granite and mica formations; he had seen several cases of granite veins near dublin, in the isle of arran, and in other parts of scotland; he had also observed several instances near morlaix in brittany, but he had in vain searched for them in the points of junction of the schist and granite, both in the maritime, savoy, swiss, and tyrolese alps, and likewise in the oriental pyrenees. the _serpentine_ district of cornwall, he thinks, has not yet met with the attention it deserves. "i have seen no formation," says he, "in which the nature of serpentine is so distinctly displayed. the true constituent parts of this rock appear to be _resplendent hornblende_ and _felspar_; it appears to differ from _sienite_ only in the nature of the _hornblende_, and in the chemical composition of its parts, and in being intersected by numerous veins of _steatite_ and _calcareous spar_." the nature and origin of the veins of _steatite_ in serpentine, he considers as offering a very curious subject for enquiry. "were they originally crystallized," he asks, "and the result of chemical deposition? or have they been, as for the most part they are now found, mere mechanical deposits?" he is inclined to the latter opinion. the felspar in serpentine, he observes, is very liable to decomposition, probably from the action of carbonic acid and water on its alkaline, calcareous, and magnesian elements; and its parts washed down by water and deposited in the chasms of the rocks, he thinks would necessarily gain that kind of loose aggregation belonging to steatite. he had some years before made a rude, comparative analysis of the felspar in serpentine, and of the soap-rock, when he found the same constituents in both of them, except that there was not any alkali or calcareous earth in the latter substance. it is very difficult to conceive, he says, that steatite was originally a crystallized substance which has been since decomposed; for, in that case, it ought to be found in its primitive state in veins which are excluded from the action of air and water; whereas it is easy to account for the hardness of some species of steatite on the former hypothesis; for mere mechanical deposits, when very finely divided, and very slowly made, adhere with a very considerable degree of force. a remarkable instance of this kind occurred to him amongst the chemical preparations of the late mr. cavendish, which, on the decease of that illustrious philosopher, had been presented to him by lord george cavendish: there was a bottle which had originally contained a solution of silica by potash; the cork, during the lapse of years, had become decayed, and the carbonic acid of the atmosphere had gradually precipitated the earth, so that it was found in a state of solid cohesion; the upper part was as soft as the steatite, but the lower portion was extremely hard, was broken with some difficulty, and presented an appearance similar to that of chalcedony. in speaking generally of the mineralogical interest of cornwall, he observes, that "it may be regarded, [greek: kat' exochên], as the country of veins; and that it is in veins that the most useful as well as the most valuable minerals generally exist, that the pure specimens are found which serve to determine the mineralogical species, and that the appearances seem most interesting in their connexion with geological theory. thus veins, which now may be considered in the light of the most valuable cabinets of nature, were once her most active laboratories; and they are equally important to the practical miner, and to the mineralogical philosopher." with regard to the general conformation of cornwall, he states it to be in the highest degree curious, and he considers that the facts which it offers are illustrative of many important points of geological theory. "it exhibits very extraordinary instances of rocks broken in almost every direction, but principally from east to west, and filled with veins again broken in, diversified by cross lines, and filled with other veins, and exhibiting marks of various successive phenomena of this kind. "respecting the agents that produced the chasms in the primary strata, and the power by which they were filled with stony and metallic matter, it would be easy to speculate, but very difficult to reason by legitimate philosophical induction." in the concluding passage, however, he very freely admits his preference for the doctrine of fire. "it is amongst extinct volcanoes, the surfaces of which have been removed by the action of air and water, and in which the interior parts of strata of lavas are exposed, that the most instructive examples of the operation of slow cooling upon heated masses are to be found. it is difficult to conceive that water could have been the solvent of the different granitic and porphyritic formations; for, in that case, some combinations of water with the pure earths ought to be found in them. quartz ought to exist in a state of _hydrate_, and wavellite, not corundum, ought to be the state of alumina in granite. "to suppose the primary rocks, in general, to have been produced by the slow cooling of a mass formed by the combustion of the metallic bases of the earths, appears to me the most reasonable hypothesis; yet aqueous agency must not be entirely excluded from our geological views. in many cases of crystallization, even in volcanic countries, this cause operates; thus in ischia, siliceous _tufas_ are formed from hot springs; and in the lake albula, or the lake of solfaterra, near tivoli, crystals of calcareous spar and of sulphur separate from water impregnated with carbonic acid and hepatic gas; and large strata of calcareous rocks, formed evidently in late times by water impregnated with carbonic acid, exist in various parts of europe. the travertine marble (_marmor tiburtinum_) is a production of this kind; and it is of this species of stone that the colosseum at rome, and the cathedral of st. peter, are built. it is likewise employed in the ancient temple of pæstum, and it rivals in durability, if not in beauty, the primary marble of paris and carrara." chapter xii. sir humphry davy suggests a chemical method for unrolling the ancient papyri.--he is encouraged by the government to proceed to naples for that purpose.--he embarks at dover.--his experiments on the rhine, the danube, the raab, the save, the ironzo, the po, and the tiber, in order to explain the formation of mists on rivers and lakes.--his arrival and reception at naples.--he visits the excavations at herculaneum.--he concludes that it was overwhelmed by sand and ashes, but had never been exposed to burning matter.--he commences his attempt of unrolling the papyri.--his failure.--he complains of the persons at the head of the department in the museum.--he analyses the waters of the baths of lucca.--his return to england.--death of sir joseph banks.--he is elected president of the royal society.--some remarks on that event.--he visits penzance.--is honoured by a public dinner.--electro-magnetic discoveries of oersted extended by davy.--he examines electrical phenomena in vacuo.--the results of his experiments questioned.--he enquires into the state of the water, and aëriform matter in the cavities of crystals.--the interesting results of his enquiry confirm the views of the plutonists. our history now proceeds to exhibit sir humphry davy in quite a new field of enquiry;--engaged in investigating, amidst the ruins of herculaneum, the nature and effects of the volcanic eruption which overwhelmed that city in the reign of titus; and in attempting, by the resources of modern science, to unfold and to render legible the mouldering archives which have been recovered from its excavations, and deposited in the museum at naples. having witnessed the unsuccessful attempts of dr. sickler to unroll some of the herculaneum manuscripts, it occurred to him that a chemical examination of their nature, and of the changes they had undergone, might suggest some method of separating the leaves from each other, and of rendering legible the characters impressed upon them. on communicating this opinion to sir thomas tyrwhitt, he immediately placed at his disposal fragments which had been operated upon by mr. hayter and by dr. sickler: at the same time, dr. young presented him with some small pieces, which he himself had formerly attempted to unroll. davy was very soon convinced by the products of their distillation, that the nature of these manuscripts had been generally misunderstood; that they had not, as was usually supposed, been carbonized by the operation of fire, but were in a state analogous to peat, or to bovey coal, the leaves being generally cemented into one mass by a peculiar substance which had formed, during the fermentation and chemical change of the vegetable matter composing them, in a long course of ages. the nature of this substance being once known, the destruction of it would become a subject of obvious chemical investigation. it occurred to him, that as chlorine and iodine do not exert any action upon pure carbonaceous substances, while they possess a strong attraction for hydrogen, these bodies might probably be applied with success for the purpose of destroying the adhesive matter, without the possibility of injuring the letters of the papyri, the ink of the ancients, as it is well known, being composed of charcoal. he accordingly exposed a fragment of a brown manuscript, in which the layers were strongly adherent, to an atmosphere of chlorine; there was an immediate action, the papyrus smoked, and became yellow, and the letters appeared much more distinct. after which, by the application of heat, the layers separated from each other, and fumes of muriatic acid were evolved. the vapour of iodine had a less distinct, but still a very sensible action. by the simple application of heat to a fragment in a close vessel filled with carbonic acid, or with the vapour of ether, so regulated as to raise the temperature very gradually, and as gradually to reduce it, there was a marked improvement in the texture of the papyrus, and its leaves were more easily unrolled. in all these preliminary trials, however, he found that the success of the experiment absolutely depended upon the nicety with which the temperature was regulated. different papyri having exhibited different appearances, he concluded that the same process would not apply in all cases; but even a partial success he considered as a step gained, and it served to increase his anxiety to examine in detail the numerous specimens preserved in the museum at naples, as well as to visit the excavations that still remained open at herculaneum. mr. hamilton, to whom these views were communicated, with that ardour which belongs to his character, entered warmly into a plan which might enable sir humphry davy to accomplish his objects; and on his representation of them, the earl of liverpool and viscount castlereagh placed at his disposal such funds as were requisite for paying the persons whom it was necessary to engage in the process. at the same time, sir humphry davy had the honour of an audience of his late majesty, then prince regent; and on witnessing the results, his royal highness was pleased to express his approbation, and graciously condescended to patronize the undertaking. exulting in the prospect of success, and sanguine as to the importance of its results to literature, davy embarked at dover for the continent, in order to proceed to naples, on the th of may . during his journey, he was engaged in making observations on the comparative temperature of air incumbent upon land and water, with a view to account for the formation of mists over the beds of rivers and lakes. the results of this enquiry were embodied in a memoir, which was read before the royal society on the th of february , and published in the philosophical transactions of that year. this paper, while it records the course of his observations, informs us of the direction of his route to the southern shores of italy. on the st of may, while passing along the rhine from cologne to coblentz, we find him examining the relative temperature of the air, and of the water of that river. on the th, th, and th of june, he was making similar observations on the danube, during a voyage from ratisbonne to vienna. on the th of july, he was similarly engaged on the raab, near kermond in hungary. in the end of august he was on the save in carniola; in the middle of september on the ironzo in the friul; in the end of that month, on the po, near ferrara; and in the beginning of october, repeatedly on the tiber, and on the small lakes in the campagna of rome, extending and multiplying his observations upon the formation of mists: from the results of which he established the law, that the formation of mist, on a river or lake, never takes place, if the temperature of the water be lower than that of the atmosphere; not even though the latter should be even saturated with vapour. possessed of this fact, he was enabled to explain a phenomenon which all persons who have been accustomed to the observation of nature must have frequently witnessed, although it had never yet been philosophically explained, nor even fully discussed, viz.--the formation of mists over the beds of rivers and lakes, in calm and clear weather, after sunset. sir humphry davy thinks that whoever has considered the phenomena in relation to the radiation and communication of heat and nature of vapour, since the publication of the researches of mm. rumford, leslie, dalton, and wells, can scarcely have failed to discover their true causes. "as soon as the sun has disappeared from any part of the globe, the surface begins to lose heat by radiation, and in greater proportions as the sky is clearer; but the land and water are cooled by this operation in a very different manner: the impression of cooling on the land is limited to the surface, and very slowly transmitted to the interior; whereas in water above ° fah., as soon as the upper stratum is cooled, whether by radiation or evaporation, it sinks in the mass of fluid, and its place is supplied by warmer water from below, and till the temperature of the whole mass is reduced nearly to °, the surface cannot be the coolest part.[ ] it follows, therefore, that wherever water exists in considerable masses, and has a temperature nearly equal to that of the land, or only a few degrees below it, and above ° at sunset, its surface during the night, in calm and clear weather, will be warmer than that of the contiguous land; and the air above the land will necessarily be colder than that above the water; and when they both contain their due proportion of aqueous vapour, and the situation of the ground is such as to permit the cold air from the land to mix with the warmer air above the water, mist or fog will be the result; which will be so much the greater in quantity, as the land surrounding or inclosing the water is higher, the water deeper, and the temperature of the water, which will coincide with the quantity or strength of vapour in the air above it, greater." [ ] water, when cooled down to °, expands in volume, and thus becomes specifically lighter; and therefore at that temperature remains at the surface. it will be remembered, that the rivers inn and ilz flow into the danube below passau; a circumstance which afforded davy an excellent opportunity of confirming, by observation and experiment, the truth of his theory. on examining the temperature of these rivers, at six o'clock a. m. june , that of the danube was found to be °, that of the inn . °, and that of the ilz °: the temperature of the atmosphere on the banks, where their streams mixed, was °. the whole surface of the danube was covered with a thick fog; on the inn there was a slight mist; and on the ilz barely a haziness, indicating the deposition of a very small quantity of water. about one hundred yards below the conflux of the rivers, the temperature of the central part of the danube was °; and here the quantity of mist was less than on the bed of the danube before the junction; but about half a mile below, the warmer water had again found its place at the surface, and the mist was as copious as before the union of the three rivers. after mists have been formed above rivers and lakes, davy considers that their increase may not only depend upon the constant operation of the cause which originally produced them, but likewise upon the radiation of heat from the superficial particles of water composing the mist, which produces a descending current of cold air in the very body of the mist, while the warm water continually sends up vapour. it is to these circumstances, he says, that the phenomena must be ascribed of mists from a river or lake sometimes arising considerably above the surrounding hills. he informs us that he had frequently witnessed such an appearance during the month of october, after very still and very clear nights, in the campagna of rome above the tiber, and on monte albano, over the lakes existing in the ancient craters of this extinguished volcano; and in one instance, on the th of october, before sunrise, there not being a breath of wind, a dense white cloud, of a pyramidal form, was seen on the site of alban lake, and rising far above the highest peak of the mountain. its form gradually changed after sunrise; its apex first disappeared, and its body, as it were, melted away in the sunbeams. great dryness of the air, or a current of dry air passing across a river, he found, as we might have expected, to prevent the formation of mist even when the temperature of the water was much higher than that of the atmosphere. thus did our philosopher, during the course of his journey to naples, by a series of observations and experiments, investigate a phenomenon connected with the deposition of water from the atmosphere, and which is not without an effect in the economy of nature; for verdure and fertility, in hot climates, generally follow the courses of rivers, and by the operation of the law he established, they are extended to the hills, and even to the plains surrounding their banks. on his arrival at naples, sir h. davy found that a letter from his royal highness the prince regent to the king, and a communication made from the secretary of state for foreign affairs to the neapolitan government, had prepared the way for his enquiries, and procured for him every possible facility in the pursuit of his objects. the different rolls of papyri presented very various appearances. they were of all shades, from a light chestnut brown to a deep black; some externally were of a glossy black, like jet, which the superintendents called "varnished;" several contained the umbilicus, or rolling-stick, in the middle, converted into dense charcoal. in their texture, also, they were as various as in their colours. the persons to whom the care of these mss. are confided, or who have worked upon them, have always attributed these different appearances to the action of fire, more or less intense, according to the proximity of the lava, which has been imagined to have covered the part of the city in which they were found; but the different conclusion at which davy had arrived, from a chemical examination in england, was confirmed by a visit to the excavations that still remained open at herculaneum. these excavations are in a loose _tufa_, composed of sand, volcanic ashes, stones, and dust, cemented by the operation of water, which, at the time of its action, was probably in a boiling state. the theatre, and the buildings in the neighbourhood, are incased in this _tufa_, and, from the manner in which it is deposited in the galleries of the houses, there can be little doubt that it was the result of torrents laden with sand and volcanic matter, and descending, at the same time, with showers of ashes and stone still more copious than those that covered pompeii. the excavation in the house in which the mss. were found, had been filled up; but a building, which was said by the guides to be this house, and which, as is evident from the engraved plan, must at least have been close to it, at once convinced davy that the parts nearest the surface, and, _à fortiori_, those more remote from it, had never been exposed to any considerable degree of heat. he found a small fragment of the ceiling of one of the rooms, containing lines of gold leaf and vermilion, in an unaltered state, which never could have happened had they been acted upon by any temperature sufficiently great to convert vegetable matter into charcoal. the different states of the mss. exactly coincide with this view, and furnish evidence of their having undergone a gradual process of decomposition. the loose chestnut papyri, he observes, were probably never wetted, but merely changed by the reaction of their elements, assisted by the operation of a small quantity of air; the black ones, which easily unroll, may be supposed to have remained in a moist state, without any percolation of water; while it is likely that the dense ones, containing earthy matter, have been acted on by warm water, which not only carried into the folds earthy matter suspended in it, but likewise dissolved the starch and gluten used in preparing the papyrus and the glue of the ink, and distributed them through the substance of the mss. as many of the papyri appear to have been strongly compressed when moist, in different positions, he thinks it probable that they had been placed on shelves of wood, which were broken down when the roofs of the houses yielded to the superincumbent mass. that the operation of fire is not at all necessary for producing such an imperfect carbonization of vegetable matter as that displayed by the mss., is at once proved by an inspection of the houses at pompeii, which was covered by a shower of ashes that must have been cold, as they fell at the distance of seven or eight miles from the crater of vesuvius; and yet the wood of its buildings is uniformly found converted into charcoal, while the colours on the walls, most of which would have been destroyed or altered by heat, are perfectly fresh. where papyri have been found in these houses, they have appeared in the form of white ashes, as of burnt paper, an effect produced by the slow action of the air penetrating through the loose ashes, and which has been impeded or prevented in herculaneum by the _tufa_, which, as it were, hermetically sealed up the town, and prevented any decay, except such as occurs in the spontaneous decomposition of vegetable substances exposed to the limited operation of water and air--for instance, peat and bovey coal. davy ascertained, that what the neapolitans called varnish, was decomposed skin that had been used to infold some of the papyri, and which by chemical changes had produced a brilliant animal carbonaceous substance, which afforded by distillation a considerable quantity of ammonia, and left ashes containing much phosphate of lime. only one method, and that a simple and mechanical, though a highly ingenious one, had been adopted for unrolling the mss. it was invented, in the middle of the last century, by padre piaggi, a roman, and consists in attaching a thin animal membrane, by a solution of glue, to the back of the mss. and then carefully elevating the layers by silk threads, which are gradually moved by the revolution of wooden pegs. davy, shortly after his arrival, desired that the process of unrolling might be continued in his presence; and in considering the method in its general application, it occurred to him that some expedient might be used to facilitate the separation of the layers. for this purpose, he proposed to mix the solution of glue with a sufficient quantity of alcohol to gelatinize it, in order that it might not penetrate through three or four layers, which it was liable to do, when the texture of the papyrus was loose or broken, and the glue employed was in a liquid state. he also suggested the application of warm air for drying the papyrus, in the operation of attaching the membrane. it is not my intention to follow the chemist through all the various processes which he instituted for accomplishing his object; they may, however, be found in his paper entitled "some observations and experiments on the papyri found in the ruins of herculaneum," which was read before the royal society on the th of march , and published in the transactions of that year. it only remains to be stated that davy was not successful; but though the process of unrolling hitherto applied may not have received any considerable improvement from his science, and though he may not have succeeded in rendering any of the manuscripts legible, the failure is not to be attributed to his want of zeal, or to his want of skill, but solely, as it is generally admitted, to the unfortunate condition of the papyri. it will be readily supposed that a failure in an investigation, from which he had anticipated so much advantage, was not sustained by a person naturally quick and irritable, without some demonstrations of impatience and dissatisfaction. it was probably under the influence of such feelings, that he composed the conclusion of his memoir. "during the two months that i was actively employed in experiments on the papyri at naples, i had succeeded, with the assistance of six of the persons attached to the museum, and whom i had engaged for the purpose, in partially unrolling twenty-three mss., from which fragments of writing were obtained, and in examining about one hundred and twenty others, which afforded no hopes of success; and i should gladly have gone on with the undertaking, from the mere prospect of a possibility of discovering some better result, had not the labour, in itself difficult and unpleasant, been made more so, by the conduct of the persons at the head of this department in the museum. at first, every disposition was shown to promote my researches; for the papyri remaining unrolled were considered by them as incapable of affording any thing legible by the former methods, or, to use their own word, _disperati_; and the efficacy and use of the new processes were fully allowed by the _svolgatori_, or unrollers of the museum; and i was some time permitted to choose and operate upon the specimens at my own pleasure. when, however, the reverend peter elmsley, whose zeal for the promotion of ancient literature brought him to naples for the purpose of assisting in the undertaking, began to examine the fragments unrolled, a jealousy with regard to his assistance was immediately manifested; and obstacles, which the kind interference of sir william a'court was not always capable of removing, were soon opposed to the progress of our enquiries; and these obstacles were so multiplied, and made so vexatious towards the end of february, that we conceived it would be both a waste of the public money and a compromise of our own characters to proceed." * * * * * while in italy, sir h. davy visited the baths of lucca, and examined the waters which have given to that place so much celebrity. the results of his analysis formed the subject of a paper, which was published in the memoirs of the royal academy of sciences at naples, of which society he was a member. at the spot where the temperature of the water was the highest, that is, in what are termed the _caldi_, or hot baths, a considerable quantity of a substance is ejected, which produces a deposit of a brownish-yellow colour. having collected a quantity of this deposit, he ascertained it to consist of oxide of iron and silica, in the proportion of about four parts of the former to three of the latter; and although the iron, at the time of its deposition, proved to be a _peroxide_, he thinks it probable that it existed in the water in the state of _protoxide_. he also supposes, that the oxide of iron and the silica had been dissolved together in the water, and been deposited from it in combination. he conceives that the fact which he had some years before noticed, of the analogy between the base of silica, and that of boracic acid, together with those observed by berzelius, furnish sufficient reasons for classing silica amongst the acids, and for rendering it probable, that the oxide of iron and silica undergo a real chemical combination in the warm water, and that they are separated from the latter in consequence of the reduction of its temperature, after it has issued from the mountain. a small portion of oxide of iron, he observes, is found in the waters of bath, in which case it is also accompanied by silica; and he believes that, in many other instances, the oxide of iron is dissolved in water through the same agency: he moreover regards such facts as throwing considerable light upon the manner in which ochre is generated. sir humphry davy returned to england in ; and, on the th of june, in the same year, his venerable friend sir joseph banks, who, notwithstanding his increasing infirmities, had continued to discharge the duties of president of the royal society to the latest period of his life, expired at his villa at spring grove, at the advanced age of seventy-seven. discussions necessarily arose as to the appointment of a proper successor, when persons of high and even exalted rank were proposed as candidates; but the more influential members of the society at once found, in their own council-chamber, two philosophers, whom they considered equally entitled to the honour of the situation, and equally well calculated for the discharge of its duties--sir humphry davy, and dr. wollaston; but the latter having signified his fixed determination to decline competition, gave the whole weight of his influence to the former; and, under that arrangement, he received from the council the compliment of being placed in the chair, until the general election of officers at the ensuing anniversary. as the period of election approached, a few fellows of the society attempted to raise a clamour in favour of some more aristocratic candidate. to this circumstance, davy alludes in the following letter. to thomas poole, esq. grosvenor street, june . my dear poole, i regret very much that you could not join me at dinner this day. to-morrow and the following day i shall be occupied by pressing affairs; but i shall be at home to-morrow till half-past eleven, and be most happy to see you. i am not very anxious to remove "mists," for i feel that the president's chair, after sir joseph, will be no light matter; and unless there is a strong feeling in the majority of the body that i am the most proper person, i shall not sacrifice my tranquillity for what cannot add to my reputation, though it may increase my power of being useful. i feel it a duty that i owe to the society to offer myself; but if they do not feel that they want me, (and the most active members, i believe, do) i shall not force myself upon them. i am, my dear poole, very sincerely yours, h. davy. on the day of election, (november , ,) there was a feeble expression in favour of lord colchester, who was abroad at the time, and had not even been made acquainted with the intention of his supporters. davy was therefore elected by an immense majority of votes. he was conducted into the meeting-room by his two friends, mr. davies gilbert and mr. hatchett, and, to the gratification of every lover of science, he ascended the chair of newton. the value which he himself attached to this triumph, may be seen in his answer to a letter of congratulation from his friend mr. poole. to thomas poole, esq. grosvenor street, dec. . my dear poole, i am much obliged to you for your congratulations. the contest to my election defeated itself, for there were only thirteen votes for lord colchester out of nearly one hundred and sixty; and, had it been known that the attempt would have been made, i should have had at least double the number. the overwhelming majority has, however, shown the good opinion of the society, which i trust and feel has not been diminished by my conduct in the chair. i have never needed any motive to attach me to science, which i have pursued with equal ardour under all circumstances, for its own sake, and for the sake of the public, uninfluenced by the fears of my friends, or the calumnies of my enemies. i glory in being in the chair of the royal society, because i think it ought to be a reward of scientific labours, and not an appendage to rank or fortune; and because it will enable me to be useful in a higher degree in promoting the cause of science. to this cause, however, i should have been always attached, even had i not been in such good humour with the public, as i have reason to be. dr. wollaston, my only formidable opponent in the beginning of the business, behaved like a true philosopher and friend of science; and mr. gilbert gave me his warmest support. i am sorry that i have said so much about myself, but your long letter called for something. i wish i could say anything satisfactory on the subject of captain parry and his officers.[ ] i have every reason to believe lord melville will do all he can on the occasion; no recommendation will be wanting from the royal society that can be given; but the admiralty is bound by certain general rules, and will not do more in this instance than they would do in the case of a brilliant combat; but these brave and scientific navigators will be rewarded by a more durable species of glory. lady davy joins me in kind remembrances. i am, my dear poole, sincerely yours, h. davy. [ ] mr. poole informs me, that he "had been anxious to interest him, as president of the royal society, in favour of those brave and scientific navigators, particularly lieutenant, now captain, liddon, who commanded the griper, in captain parry's first voyage." it was a question anxiously discussed by the friends of davy, how far his elevation to the chair of the royal society was calculated to advance the cause of science, or to increase the lustre of his own fame. it will be readily perceived that this is a question perplexed by various conflicting interests, for it not only involves considerations relating to the character of the person, but to that also of the constitution and objects of the society over which he is called upon to preside. it is still doubtful whether the royal society, in the present advanced state of science, can derive advantage from possessing in its president, a philosopher actively engaged in any one branch of experimental enquiry. sir humphry davy, in his first address from the chair, took occasion to observe, that "in the early periods of the establishment, when apparatus was procured with difficulty, when the greatest philosophers were obliged to labour with their own hands to frame their instruments, it was found expedient to keep in the rooms of the society a collection of all such machines as were likely to be useful in the progress of experimental knowledge; and curators and operators were employed, by whom many capital experiments were made under the eyes of the society.[ ] but since the improvement of the mechanical and chemical arts has afforded greater facilities as to the means of carrying on experimental research, the transactions of the fellows, recorded by the society, have, with some few exceptions, been performed in their own laboratories, and at their own expense." [ ] the charter of the royal society states that it was established for the improvement of natural science. this epithet "_natural_" was originally intended to imply a meaning of which very few persons, i believe, are aware. at the period of the establishment of the society, the arts of witchcraft and divination were very extensively encouraged; and the word natural was therefore introduced, in contradistinction to _super_-natural. although sir walter scott, in his demonology, alludes to the influence of this society in diminishing the reigning superstition, he does not appear to have been acquainted with the circumstance here alluded to. in deciding upon the qualifications necessary for a president, this altered state of the society must not be overlooked; nor can it be concealed, that the great discoveries of modern science have been achieved without any direct assistance from the royal society. davy would have discovered the laws of electro-chemistry, and applied them for the decomposition of the alkalies--and the genius of dalton would, by his atomic doctrine, have "snatched the science from the chaos of indefinite combination, and have bound it in the chains of number," had the society never existed. at the same time, it must be allowed that, although it may not have directly advanced the progress of science, it has materially assisted its cause, by perpetuating the spirit of philosophical enquiry, and the love of scientific glory--by keeping alive upon the altar the sacred flame that genius may have kindled. in the present state of science, the royal society imparts an inspiring principle to its various branches, by affording a rallying point, a centre of communication, to the philosophers of all nations, to whom kindred pursuits may render personal intercourse beneficial; and it becomes the paramount duty of the chief of this great republic so to preside over its arrangements, as to foster and encourage such an alliance. to this end, he must promote feelings of mutual kindness and liberality; and as the friend and umpire to all parties, it is his office to settle disagreement, to soothe disappointment, to kindle hope, and to subdue the vehemence which "engenders strife," in order that rivalship shall not pass into hostility, nor emulation degenerate into envy. it is evident that the talents and qualifications necessary for the discharge of such duties are of the highest order, extensive in their range, and diversified in their character. to which, however harshly the word may grate upon the ear of the philosopher, wealth must be considered as an essential and indispensable condition. it may be fairly asked, whether a philosopher actively engaged in the pursuit of any branch of science, is so well adapted for the performance of such varied duties, as the person who possesses a general acquaintance with every department, but is not exclusively devoted to the investigation of any one branch; for, however correct may be his decisions, or unbiassed his judgment, the conduct of the former will ever be open to the charge of partiality, and the bare existence of such a suspicion, though it may be wholly groundless, will carry with it a train of evils. it is not in human nature to believe that the looker-on, and he who plays the game, are alike indifferent to the cards.[ ] [ ] i state this opinion with the greater confidence, from a conviction that it is not singular. on conversing lately upon the subject with a gentleman to whom the royal society is deeply indebted for the sound judgment and discretion he displayed on occasions greatly affecting its interests, he replied, "sir, we require not an achilles to fight our battles, but an agamemnon to command the greeks." on the other hand, it may be urged with some force, that the presidency of the royal society should be reserved as the fair reward of scientific labours, and not as an appendage to rank or to wealth:--that in england, we may in vain search amongst the aristocracy for one who feels a dignified respect for the sciences, and who is willing to afford that time which the faithful discharge of its duties would require. to assert that davy retained his popularity, or to deny that he retired from the office under the frown of a considerable party, would be dishonest. i would willingly dismiss this part of his life without too nice an examination; but i am writing a history, not an eloge. as a philosopher, his claims to admiration and respect were allowed in all their latitude; but when he sought for the homage due to patrician distinction, they were denied with indignation. how strange it is, that those whom nature has placed above their fellow men by the god-like gift of genius, should seek from their inferiors those distinctions which are generally the rewards of fortune. when we learn that congreve, in his interview with voltaire, prided himself upon his fashion rather than upon his wit; that byron was more vain of his heraldry than of his "pilgrimage of childe harold;" that racine pined into an atrophy, because the monarch passed him without a recognition in the ante-room of the palace, and that davy sighed for patrician distinction in the chair of newton, we can only lament the weakness from which the choicest spirits of our nature are not exempt. will philosophers never feel, with walpole, that "a genius transmits more honour by blood than he can receive?" had the blood of forty generations of nobility flowed in the veins of davy, would his name have commanded higher homage, or his discoveries have excited greater admiration? but great minds have ever had their points of weakness: an inordinate admiration of hereditary rank was the cardinal deformity of davy's character; it was the centre from which all his defects radiated, and continually placed him in false positions; for the man who rests his claims upon doubtful or ill-defined pretensions, from a sense of his insecurity, naturally becomes jealous at every apparent inattention, and he is suspicious of the sincerity of that respect which he feels may be the fruit of usurpation. if with these circumstances we take into consideration the existence of a natural timidity of character, which he sought to conquer by efforts that betrayed him into awkwardness of manner, and combine with it an irritability of temperament which occasionally called up expressions of ill-humour, we at once possess a clue by which we may unravel the conduct of our philosopher, and the consequences it brought upon himself during his presidency of the royal society. nor must we leave out of sight that inattention to certain forms which, amongst those who are incapable of penetrating beyond the surface of character, passes for the offensive carelessness of superiority. davy, after the example of sir joseph banks, opened his house on one evening of the week for the reception of the fellows of the royal society, and of other persons who were actively engaged in any scientific pursuit; but the invitations to these _soirées_ were so irregularly managed, that they frequently gave offence, where they were intended to convey a compliment. conflicting opinions, respecting the management of the royal institution, most unfortunately also arose, and the president of the royal society, presuming upon his former alliance with that establishment, and upon the high obligations conferred upon it by the splendid discoveries he had achieved within its walls, was encouraged to exercise an authority which provoked an angry dissatisfaction;--schisms arose, and the party-spirit thus kindled in albemarle street soon spread to somerset house.--but let us turn to the brighter part of the picture. in the discharge of the more important duties of his office, the society received the full benefit of his talents and his virtues. at its meetings, he was constant in attendance, and dignified in his conduct and deportment; in its councils, he was firm in his resolves, correct in his judgments, zealous in his plans,[ ] and impartial in his decisions. it has been said that he unduly favoured the pursuits of chemistry, to the injury and depression of the other branches of science: this is not the fact, as a reference to the philosophical transactions will amply testify; and the awards of the copley medals will moreover show, that he alike extended the animating influence of his patronage to every part of natural philosophy. i am authorised by sir james south to state, that during his negotiations with the government, for the purpose of securing to the british nation the unalienable use of his splendid instruments, by the erection of a permanent observatory, sir humphry davy was indefatigable in his exertions to accomplish so important an object; and that on one occasion, in the midst of severe illness, he travelled at no inconsiderable risk to london, from the distant seat of his friend mr. knight, to advocate a cause so essential, in his judgment, to the interests of astronomy. [ ] it was well known to his friends that, had his health not declined, he would have carried into effect a reform which he had long contemplated, and by which the royal society would have become, at once, more dignified and more useful. * * * * * in the autumn of , davy visited his mother and relatives at penzance; upon which occasion he received from the inhabitants of the town, and from the gentlemen resident in its neighbourhood, a flattering testimony of respect, which made a deep and lasting impression upon his heart. at a general meeting, summoned for the purpose of taking into consideration some mode by which his fellow-townsmen might express their sense of his transcendent talents, and of the lustre which his genius had cast upon the place of his nativity:--it was unanimously resolved-- "that a public dinner be given to sir humphry davy, and that the mayor be desired to wait upon him forthwith, in order to communicate the resolution, and respectfully to request that he would appoint the day, on which it would be agreeable to him to meet their wishes." on the day appointed, a deputation of gentlemen proceeded in their carriages to the house of his mother, for the purpose of conducting him to the hotel, where an appropriate entertainment had been provided for the occasion. the following letter evinces the sincere satisfaction which this visit afforded him. to thomas poole, esq. penzance, july , . my dear poole, an uncontrollable necessity has brought me here. close to the land's-end i am enjoying the majestic in nature, and living over again the days of my infancy and early youth. the living beings that act upon me are interesting subjects for contemplation. civilization has not yet destroyed in their minds the semblance of the great parent of good. nature has done much for the inhabitants of mount's bay, by presenting to their senses all things that can awaken in the mind the emotions of greatness and sublimity. she has placed them far from cities, and given them forms of visible and audible beauty. i am now reviving old associations, and endeavouring to attach old feelings to a few simple objects. i am, &c. h. davy. although the letter which follows is without date, i am unwilling to withhold it. to thomas poole, esq. my dear poole, i have been for some weeks absent from london, and have only just received your letter. when i return in the winter, i shall be glad to see mr. a.--i regret that your niece is so much indisposed. lady davy has been obliged to change her climate in consequence of a long-continued cough, but i am happy in being able to say she is now quite well. after the fatigues of a long season in london, i am now enjoying the highland scenery and sports with a purer pleasure, and i find, after the alps and pyrenees, even the mountains of scotland possessing some peculiar beauties. you ought to come and see this country, which you would enjoy, both as a lover of nature and of man. the one is grand and beautiful; the other, moral, active, and independent. i am, my dear poole, your obliged friend, h. davy. the philosophical transactions, during the presidency of sir humphry davy, evince the alacrity with which he redeemed the pledge given to the society in his address on taking the chair-- "and though your good opinion has, as it were, honoured me with a rank similar to that of general, i shall be always happy to act as a private soldier in the ranks of science." * * * * * many years before even the identity of lightning and electricity was suspected, it had been observed, on several occasions, that the magnetism of the compass needle was not only destroyed, which might have been attributed to heat, but that it was even reversed by lightning.[ ] [ ] davy observes, that there are many facts recorded in the philosophical transactions, which prove the magnetising powers of lightning: one in particular, where a stroke of lightning passing through a box of knives, rendered most of them powerful magnets.--_philosophical transactions_, no. , p. , and no. , p. . in the progress of electrical discoveries, the similarity between electricity and magnetism had not escaped observation,[ ] and some philosophers had even attempted to establish the existence of an identity or intimate relation between these two forces. the experiments of ritter, however, alone appeared to offer any confirmation of the supposed analogy; but so obscure was his language, and so wild and hypothetical his views, that few, if any, of them were repeated either in france or england, and their results were for a long time wholly disregarded. [ ] the phenomena of many crystallized minerals which become electric by heat, and develope opposite electric poles at their two extremities, offered an analogy so striking to the polarity of the magnet, that it seemed hardly possible to doubt a closer connection of the two powers. the developement of a similar polarity in the voltaic pile pointed strongly to the same conclusion; and experiments had even been made with a view to ascertain whether a pile in a state of excitement might not manifest a disposition to place itself in the magnetic meridian.--_herschel's discourse_, p. . in a work, entitled "recherches sur l'identité des forces chimiques et electriques," published by m. oersted in the year , the subject was resumed, and the author advanced the hypothesis,[ ] which twelve years afterwards conducted him to one of the most important discoveries of the present age, and which has given origin to a new science, termed electro-magnetism.[ ] [ ] the hypothesis was this:--"in galvanism, the force is more _latent_ than in electricity, and still more so in magnetism than in galvanism; it is therefore necessary to try whether electricity, in its _latent_ state, will not affect the needle." this passage may be thus explained: when the voltaic circuit is interrupted, it possesses opposite electrical poles; and when continuous, it no longer affects the electrometer, or the electricity becomes _latent_, which is the condition theoretically required for the manifestation of its magnetic action: and the fundamental experiment of oersted proved that, under these circumstances, the compass needle was affected. [ ] mr. herschel, in speaking of the pertinacity with which oersted adhered to the idea of a necessary connection between electricity and magnetism, observes, that there is something in it which reminds us of the obstinate adherence of columbus to his notion of the necessary existence of the new world. in the winter of , professor oersted, secretary to the royal society of copenhagen, published an account of some experiments, in which the electric current, such as is supposed to pass from the positive to the negative pole of a voltaic battery, along a wire which connects them, caused a magnetic needle near it to deviate from its natural position, and to assume a new one, the direction of which was observed to depend upon the relative position of the needle and the wire.[ ] [ ] for this discovery, the president and council of the royal society adjudged to m. oersted the medal on sir godfrey copley's donation for the year . it may be necessary to premise, that these experiments were conducted in a form which had never before suggested itself to the enquirer; _viz. with the two ends of the pile in communication with each other_,--a condition which enabled it to discharge itself freely: this circumstance will, at once, explain the reason of all preceding failures. it was never before suspected that the electric current, passing _uninterruptedly_ through a wire, connecting the two ends of a voltaic battery, was capable of being manifested by any effect; the experiments, however, in question furnished an unequivocal test of its passage by its action on the magnetic needle; and which may be shortly stated as follows: the opposite poles of a battery, in full action, were joined by a metallic wire, which, to avoid circumlocution, has been called the _uniting conductor_, or the _uniting wire_. on placing the wire above the magnet and parallel to it, the pole next the negative end of the battery always moved westward, and when the wire was placed under the needle, the same pole went towards the east. if the wire was on the same horizontal plane with the needle, no declination whatever took place, but the magnet showed a disposition to move in a vertical direction; the pole next the negative side of the battery being depressed when the wire was to the west of it, and elevated when it was placed on the east side. the extent of the declination occasioned by a battery, depends upon its power, and the distance of the uniting wire from the needle. if the apparatus is powerful, and the distance small, the declination will amount to an angle of forty-five degrees or more; but this deviation does not give an exact idea of the real effect which may be produced by galvanism; for the motion of the needle is counteracted by the magnetism of the earth. when the influence of this latter power is destroyed by means of another magnet, the needle will place itself directly across the connecting wire: so that the real tendency of a magnet is to stand at right angles to an electric current. such phenomena, being wholly at variance with the laws of simple electrical attraction and repulsion, are only to be explained upon the supposition that a new energy is generated by the action of the current of electricity thus brought into conflict, and which must be identical with, or nearly related to, magnetism. it would also appear from the motions of the magnet, when differently placed with regard to the _uniting wire_, that this energy circulates, or performs a circular movement around the axis of the conductor, and thus drives the magnetic pole according to the direction of the needle with reference to such a current. this important discovery was no sooner announced to the philosophical world, than sir humphry davy, with his characteristic zeal, proceeded to repeat the experiments; and, with his usual sagacity, so to vary and extend them, as to throw new light upon this novel department of science. the facts he thus discovered, and the reasonings founded upon them, were communicated by him to the royal society in three successive memoirs. the first, "on the magnetic phenomena produced by electricity," was read on the th of november . the second, entitled "farther researches on the magnetic phenomena produced by electricity; with some new experiments on the properties of electrified bodies, in their relations to conducting powers and temperature," read july th, . the third, "on a new phenomenon of electro-magnetism," read march th, . the principal experiments communicated in these memoirs were performed with the battery belonging to the london institution,[ ] the once powerful apparatus at the royal institution having become old and feeble in his service. [ ] i find from a note addressed to mr. pepys, that on the st of june, , davy worked the two batteries of plates each at the london institution, before the prince royal of denmark. the experiments were principally electro-magnetic. the following letter contains an invitation to his friend mr. pepys, to witness his first experiment; a document so far valuable, as it fixes a date of some importance in the history of discovery. to william hasledine pepys, esq. grosvenor street, oct. , . dear pepys, the experiment i wish to show you is no less than the conversion of electricity into magnetism; but it is a secret as yet. i will come to you at twelve on monday, in the poultry. if you will be so good as to order the battery to be charged to-morrow, it will be ready for us on monday. have you a dipping needle? this, and an air-pump, and the globe for taking sparks _in vacuo_ by points of charcoal, are all we shall want. perhaps you will invite dr. babington, and our worthy friend allen. i will show you the opening of quite a new field of experiment. ever yours very sincerely, h. davy. the discovery of professor oersted was limited to the action of the electric current on needles previously magnetised. davy ascertained that the _uniting conductor itself became magnetic_, during the passage of the electricity through it.[ ] it was in consequence of having observed some anomaly, with respect to the way in which the uniting wire altered the direction of the magnet, that he was led to a conjecture which he immediately verified by a very simple experiment. he threw some iron filings on a paper, and brought them near the uniting wire, when immediately they were attracted by the wire, and adhered to it in considerable quantities, forming a mass round it ten or twelve times the thickness of the wire: on breaking the communication, they instantly fell off, proving that the magnetic effect entirely depended upon the passage of electricity through the wire. [ ] it would appear that m. arago likewise discovered this fact at about the same period; but it is evident that the french and english philosophers arrived at the result independently of each other; for the experiments which led to it were made by sir h. davy in october ; while the september number of the "annales de physique," containing the first account of the researches of m. arago, was not received in london until the th of november in that year; and it may be farther observed, that the numbers of this journal were very commonly published several months after the affixed date. davy observes, it was easy to imagine that such magnetic effects could not be exhibited by the electrical wire, without its being capable of permanently communicating them to steel; and that, in order to ascertain whether such was the fact, he fastened several steel needles, in different directions, to the uniting wire, when those parallel to it were found to act like the wire itself, while each of those placed across it acquired two poles. such as were placed _under_ the wire, the positive end of the battery being east, had north poles on the south of the wire, and south poles to the north. the needles _above_ were in the opposite direction; and this was constantly the case, whatever might be the inclination of the needle to the wire. on breaking the connexion, the steel needles, placed _across_ the uniting wire, retained their magnetism,[ ] while those placed _parallel_ to it lost it at the moment of disunion. the most extraordinary circumstances, however, connected with these experiments were, first, that _contact_ with the uniting wire was not found necessary for the production of the effect,--indeed, it was even produced, though thick glass intervened; and, secondly, that a needle which had been placed in a transverse direction to the wire, merely for an instant, was found as powerful a magnet as one that had been long in communication with it. [ ] m. arago also, nearly at the same time, succeeded in communicating magnetism to the needle; but, at the suggestion of m. ampère, it was effected in a different manner. a copper wire, by being rolled round a solid rod, was twisted into a spiral, so as to form a _helix_. it was easy, by passing the wire round the rod, in one direction or the other, to form a _dextrorsal_ helix, proceeding from the right hand towards the left, as in the tendrils of many plants; or a _sinistrorsal_, or left helix, proceeding downwards from the left hand to the right above the axis. into the cavity of a spiral thus formed, connecting the two poles of a battery, a steel needle wrapped in paper was introduced; and, in order to exclude all influence of the magnetism of the earth, the conchoidal part of the wire was kept constantly perpendicular to the magnetic meridian. in a few minutes the needle had acquired a sufficiently strong dose of magnetism; and the position of the north and south poles exactly agreed with m. ampère's notion, that the electric current traverses the connecting wire in a direction from the zinc extremity of the pile to the copper extremity. the distance to which magnetism is communicated by electricity, and the fact of its taking place equally through conductors and non-conductors, are circumstances which, in the opinion of davy, are unfavourable to the idea of the identity of electricity and magnetism. davy subsequently ascertained by experiment, that the magnetic result was proportional to the quantity of electricity passing through a given space; and this fact led him to believe, that a wire electrified by the common machine would not occasion a sensible effect; and this he found to be the case, on placing very small needles across a fine wire connected with a prime conductor of a powerful machine and the earth. but as a momentary exposure in a powerful electrical circuit was sufficient to give permanent polarity to steel, it appeared equally obvious, that needles placed transversely to a wire at the time that the electricity of a common leyden battery was discharged through it, ought to become magnetic; and this he found was actually the fact, and according to precisely the same laws as in the voltaic circuit; the needle _under_ the wire, the positive conductor being on the right hand, offering its north pole to the face of the operator, and the needle _above_, exhibiting the opposite polarity. the facility with which experiments are made with the common leyden battery, enabled him to ascertain various other important facts, respecting the communication of magnetism, which it would be inconsistent with the nature and limits of this work to particularize. i have merely offered a notice of the more prominent discoveries communicated by him in his first paper to the royal society, and which he concludes by observing, that "in consequence of the facts lately developed, a number of curious speculations cannot fail to present themselves to every philosophical mind; such as whether the magnetism of the earth may not be owing to its electricity, and the variation of the needle to the alterations in the electrical currents of the earth, in consequence of its motions, internal changes, or its relations to solar heat; and whether the luminous effects of the auroras at the poles are not shown, by these new facts, to depend on electricity. this is evident, that if strong electrical currents be supposed to follow the apparent course of the sun, the magnetism of the earth ought to be such as it is found to be."[ ] [ ] a very ingenious piece of apparatus was contrived to illustrate this theory by experiment; but i am uncertain as to whom the credit of it belongs. it consisted of a globe, containing metallic wires, arranged in relation to each other according to the electro-magnetic theory, when, by passing an electric current in the direction of the ecliptic, the poles became magnetic. davy never overlooked an occasion of applying theory to practice, and he therefore proposes, upon the principles developed in this paper, to make powerful magnets, by fixing bars of steel, or circular pieces of steel, fitted for making horse-shoe magnets, round the electrical conductors of buildings in elevated and exposed situations. his second paper contains an account of experiments instituted with a view to gain some distinct knowledge on the subject of the relations of the different conductors to the magnetism produced by electricity. the results were decisive; but, without entering minutely into the theory of the subject which they so ably illustrated, these experiments cannot be clearly described, or successfully explained. the same observation will apply to the researches detailed in his third paper, announcing the discovery of a _new electro-magnetic phenomenon_; for, since they are inseparably connected with mr. faraday's beautiful experiments on _magnetic rotation_, i could scarcely expect to render my analysis of the memoir sufficiently intelligible, without entering at length upon that curious subject; i am unwilling, however, to refer the reader to the original paper in the transactions, without offering a remark upon the _phenomenon_, which he says "is the _principal_ object of the paper," but which we might conclude, from the hasty and imperfect manner in which he dismisses it, to have occupied a very subordinate place in his estimation. in his anxiety to examine and describe the rotations produced during this experiment, he bestows far too little attention upon the more, indeed i might say the _only_, important phenomenon of the cone of mercury which was elevated above each of the wires proceeding from the battery; and which, arising as it evidently did from a repulsive influence, clearly shows that the presence of electricity establishes between the particles of matter a repulsive energy, whether that matter be conducting, or non-conducting in its functions. this law, m. ampère subsequently illustrated by a different form of experiment, and unfairly, as i must think, omitted even to notice davy's prior result. on the th of december , davy communicated to the royal society a memoir "on the electrical phenomena exhibited _in vacuo_." it had been stated by mr. walsh, and the opinion had been subsequently supported by the researches of mr. morgan, that the electrical light was not producible in a perfect torricellian vacuum; the latter gentleman also concluded that such a vacuum prevented the charging of coated glass. an enquiry of greater importance can scarcely be imagined; involving in its train several of the most abstruse and difficult questions of corpuscular philosophy; as, whether electricity be a subtile fluid, or electrical effect the mere exhibition of the attractive powers of the particles of bodies; for, if it can be shown that these effects take place in a perfect vacuum, we shall advance towards the conclusion, that electrical phenomena depend upon the agency of an ethereal and transcendental fluid. it was under such an impression that davy proceeded to determine, if possible, "the relations of electricity to space, as nearly void of matter as it can be made on the surface of the earth." he was, in the first instance, led to suspect the accuracy of those conclusions at which mr. walsh and mr. morgan had arrived, from considering that, "in the most perfect vacuum which can be obtained in the torricellian tube, vapour of mercury, though of extremely small density, must still always exist." i propose to follow our philosopher through the paths of this enquiry; and then, with all the deference due to such high authority, to state the objections which may be urged against his results. first, then, as to the results he obtained with quicksilver in an apparatus simple, but well adapted at once to insure the most completely attainable vacuum, and to exhibit its capability of receiving a charge. in all cases where this vacuum was perfect, he found it to be permeable to electricity, and to be rendered luminous, either by the common spark, or by the shock from a leyden jar; and, moreover, that the coated glass surrounding it became charged under such circumstances; but the intensity of the light in these experiments was always in proportion to the temperature, or, in other words, to the density of the mercurial vapour; and that at ° below zero of fahrenheit, it became so faint as to require considerable darkness to render it perceptible. the great brilliancy, on the other hand, of the electrical light in pure, dense vapour of mercury, was beautifully displayed during the operation of boiling the metal in an exhausted tube. "in the formation and condensation of the globules of mercurial vapour, the electricity produced by the friction of the mercury against the glass, was discharged through the vapour with sparks so bright as to be visible in daylight." the charge likewise communicated to the tinfoil was higher, the higher the temperature; at ° fahrenheit it was extremely feeble. this, like the phenomenon of the electric light, must, he thinks, depend upon the different density of the vapour of mercury. but he was desirous of still farther refining his experiments, so as to exclude, as far as it was possible, the presence of any volatile matter; and in this part of the enquiry he displayed, in a very masterly manner, that happy talent in which he so far surpassed his contemporaries, of suggesting expedients and contriving new apparatus in order to vanquish practical difficulties. to get rid of a portion of mercurial vapour, he employed a difficultly fusible amalgam of mercury and tin, which was made to crystallize by cooling in the tube; but, in this case, the results were precisely the same as when pure mercury had been used. he then attempted to make a vacuum above the fusible alloy of bismuth, but he found it so liable to oxidate and soil the tube, that he soon renounced farther attempts of this kind. nothing discouraged, he determined to try the effects of a comparatively fixed metal in fusion. by melting freshly cut pieces of grain tin, in a tube made void after having been filled with hydrogen, and by long-continued heat and agitation, he obtained a column of fixed metal which appeared to be entirely free from gas; and yet the vacuum made above this exhibited the same phenomena as the mercurial vacuum, except that they were not perceptibly increased by heat: a fact which davy must have anticipated, as he attributed the greater display of electrical light, at high temperatures, to the effect of increased density of vapour; it is therefore a matter of surprise that he did not give more importance to the phenomenon. he made two experiments on electrical and magnetic repulsions and attractions in the mercurial vacuum, and he found that two balls, the one of platinum, the other of steel, properly arranged for the purpose, repelled each other, when the conducting wire to which they were attached was electrified in the most perfect mercurial vacuum, as they would have done in the usual cases: and that the steel globules were as obedient to the magnet as in the air; which last result, he observes, it was easy to have anticipated. he also made some comparative experiments, with the view of ascertaining, whether below the freezing point of water the diminution of the temperature of the torricellian vacuum diminished its power of transmitting electricity, or of being rendered luminous by it. to about twenty degrees, this appeared to be the case; but between twenty degrees above, and twenty degrees below zero, the lowest temperature he could produce by pounded ice and muriate of lime, it seemed stationary; and, as well as he could determine, the electrical phenomena were very nearly of the same intensity as those produced in the vacuum above tin. "it is evident," he says, "from these general results, that the light (and probably the heat) generated in electrical discharges depends _principally_ on some properties or substances belonging to the ponderable matter through which it passes: but they prove likewise that space, where there is no appreciable quantity of this matter, is still capable of exhibiting electric phenomena--viz. those of attraction and repulsion, &c.: a fact unquestionably favourable to the idea of the phenomena of electricity being produced by a highly subtile fluid or fluids, of which the particles are repulsive with respect to each other, and attractive of the particles of other matter." however much we may admire the experimental address displayed in this paper, we must confess that its results are very far from being satisfactory. his having assumed, without proof, and even without examination, the theory that a perfect vacuum cannot be produced in the torricellian tube, and made it the foundation of his reasonings, appears to me to have vitiated all his conclusions. mr. faraday has rendered it extremely probable, that a _limit_ does actually exist to the production of vapour by bodies placed _in vacuo_,[ ] beneath which they are perfectly fixed; and if this be true, it is evident that, at low temperatures, a perfect vacuum may be produced in the torricellian tube; and it is highly probable that davy did thus actually produce one in several of his experiments; especially in those where he found that, by a farther reduction of temperature, no farther diminution of electrical effect was perceptible: he had in fact arrived at this limit to vaporization, and therefore a farther reduction of temperature could not possibly influence the phenomena. in this point of view, the electrical light would seem to be _primary_, or independent of foreign matter.--but though the premises be granted, let the reader pause before he hastens to any conclusion; for the cloud of mystery has not been dissipated, it has only changed its place. at the termination of his paper, davy indulges in a conjecture subversive of every conclusion deduced from experiments _in vacuo_. "when the intense heat," says he, "produced by electricity, and the strong attractive powers of differently electrified surfaces, and the rapidity of the changes of state, are considered, it does not seem at all improbable, that the superficial particles of bodies, which, when detached by the repulsive power of heat, form vapour, may be likewise detached by electrical powers, and that they may produce luminous appearances in a vacuum free from all other matter, by the annihilation of their opposite electrical states." [ ] "on the existence of a limit to vaporization. by m. faraday, f.r.s. corresponding member of the royal academy of sciences at paris." phil. trans. . see also a more recent paper by the same philosopher in the first number of the new journal of the royal institution. during the course of the enquiry, davy is led to suppose that air may exist in mercury, in the same invisible state as it does in water, that is, distributed through its pores; and that absorption of air may, therefore, explain the difference of the heights of the mercury in different barometers. this, it must be confessed, if true, is a most disheartening fact, as it at once precludes the possibility of any thing like accuracy in our barometers; but mr. daniell, to whom on all subjects of meteorology we are bound to pay the greatest deference, differs altogether from our philosopher upon this point, and he adduces a single observation which he thinks nearly disproves the supposition. "all fluids," says he, "which are known to absorb air into their pores, invariably emit it when the pressure of the atmosphere is removed; but, upon an extensive examination of large bodies of mercury, variously heated in the vacuum of an air-pump, i never saw a bubble of air given off from the surface of the metal." davy, it must be stated, obtained a far different result; but an observation of mr. daniell explains the cause of it. "air," he continues, "will rise from the contact of the mercury with the glass in which it is contained, in exact inverse proportion to the care with which it has been filled, but it _never rises from the surface of the mercury alone_. the difficulty of properly filling a barometer tube, i attribute to the attraction between the glass and the air--not to that between the mercury and the air."[ ] [ ] "meteorological essays and observations," p. .--see also bellani's experiments upon this subject, which are so satisfactory as to remove every doubt from the subject. on the th of june , a memoir was read before the royal society, "on the state of water and aëriform matter in cavities found in certain crystals. by sir humphry davy, bart. p.r.s." it is generally admitted by geologists, that the greater number of the crystalline substances of the mineral kingdom must have been previously in a liquid state; but different schools have assumed different causes for their solution; some attributing the effect principally to the agency of water, others to that of heat. in the paper under consideration, the author very freely avows himself as the champion of the latter doctrine. "when it is considered," says he, "that the solvent power of water depends upon its temperature, and its deposition of solid matters upon its change of state or of temperature, and that, being a gravitating substance, the same quantity must always belong to the globe, it becomes difficult to allow much weight to the arguments of the wernerians, or neptunists, who have generally neglected, in their speculations, the laws of chemical attraction. "there are many circumstances, on the contrary, favourable to that part of the views of the huttonians, or plutonists, relating to the cause of crystallization; such as the form of the earth, that of an oblate spheroid flattened at the poles; the facility with which heat, being a radiating substance, may be lost and dissipated in free space; and the observations which seem to show the present existence of a high temperature in the interior of the globe." he had often, he tells us, in the course of his chemical researches, looked for facts, or experiments, which might throw some light on this interesting subject, but without success, till it occurred to him, as he was considering the state of the fluid and aëriform matters which are found included in certain crystals, that these curious phenomena might be examined in a manner to afford some important arguments as to the formation of the crystal itself. having obtained, through the liberality of his friends, a variety of appropriate specimens of rock-crystal, he proceeded to submit them to experiment. their cavities were opened by means of diamond drills, under either distilled water, oil, or mercury; the gas was then expelled from them by the introduction of slender wires, and the included fluids were drawn out by the aid of fine capillary tubes. as soon as an opening was effected, the fluid under which the operation had been performed rushed into the cavity, and the globule of elastic fluid contracted so as to appear from six to ten times less than before the experiment. the fluid was found to be nearly pure water,--the gas appeared to be azote. it was an interesting point to ascertain whether the same circumstances occurred in productions found in rocks which have been generally considered as of igneous origin, such as the basaltic rocks in the neighbourhood of vicenza, the chalcedonies of which so often afford water. on examining such specimens, when, to obviate the possibility of any fallacy, they were previously ascertained to be impermeable to the atmosphere, analogous results were obtained: water, containing very minute quantities of saline impregnations, was found to be the fluid, and the gas, as in the former instances, was ascertained to be azote; but it was in a much more rarefied state than in the rock-crystals, being between sixty and seventy times as rare as atmospheric air. the fact of azote being found in these cavities, he explains, by supposing that atmospheric air might have been originally included in the crystals, and that the oxygen had been separated from it by the attraction of the water; a conjecture which a direct experiment appeared to confirm. in reasoning upon the vacuum, or rarefied state of the aëriform matter in the cavities of rock-crystals and chalcedonies, he very justly states, that the phenomenon cannot be easily accounted for, except on the supposition of their having been formed at a higher temperature than that now belonging to the surface of the globe: and he thinks it most probable that the water and the silica were in chemical union, and separated from each other by cooling, since there are strong grounds for believing that a liquid _hydrate of silica_ would exist at high temperatures under pressure, and that, like all liquid bodies in the atmosphere, it would contain small quantities of atmospheric air. if this be granted, we may readily explain the phenomena presented by the gaseous and liquid matters in rock-crystal and chalcedony. thus then did davy assail the neptunists in their own camp, and vanquish them with their own weapons; for the fact, which had been confidently considered by the disciples of werner, as, above all others, hostile to the idea of the igneous origin of crystalline rocks, namely, the existence of water in them, has been made to afford a decisive argument in favour of the very opinion it had been brought forward to oppose.[ ] [ ] i well remember with what triumph the late dr. clarke, in his popular lectures on mineralogy at cambridge, paraded a fine crystal containing water in its cavity. "gentlemen," said he, "there is water enough in the very crystals in my cabinet to extinguish all the fires of the plutonists." in an appendix to the foregoing paper, the examination of two other crystals is detailed; the results afforded were very different from those of the preceding ones, but not less favourable to the theory of igneous origin. one of these crystals was found to contain a bituminous fluid; on piercing it under distilled water, the water rushed in, and entirely filled the cavity, so that no aëriform matter but the vapour of the substance could have been present. the fact of almost a perfect vacuum existing in a cavity containing an expansible but difficultly volatile substance, must be considered as highly favourable to the theory of the igneous origin of crystals. in the other crystal, the quantity of aëriform matter was unusually small in proportion to the quantity of fluid, and from the peculiarity of its motion, it appeared to be more likely to be compressed than rarefied elastic fluid; and in piercing the sides of the cavities, davy found that this was the case; it enlarged in volume from ten to twelve times; the fluid was water, but the gas was too minute in quantity to be examined. there is but one mode of accounting for this phenomenon. the crystal must have been formed under an immense weight of atmosphere or fluid, sufficient to produce a compression much more than adequate to compensate for the expansive effects of heat.[ ] [ ] an explanation which the experiments of mr. faraday, on the condensation of the gases, to be immediately described, will most fully justify. chapter xiii. the liquefaction of chlorine gas first effected by mr. faraday, and witnessed by the author.--sir h. davy continues the investigation.--his paper on the application of liquefiable gases as mechanical agents.--other probable uses of these bodies.--he proposes several methods to prevent the fumes which arise from smelting-furnaces.--importance of the subject. his letters to mr. vivian.--the government solicit the advice of the royal society on the subject of protecting the copper sheathing of ships from the action of sea-water.--sir h. davy charges himself with this enquiry.--he proposes a plan of protection founded on voltaic principles.--his numerous experiments.--he embarks on board the comet steam-vessel bound to heligoland, in order to try his plan on a vessel in motion.--he arrives at mandal, lands, and fishes in the lakes.--the protectors washed away.--he teaches the inhabitants of christiansand to crimp fish--he remains a few days at arendal.--a norwegian dinner.--the protectors are examined and weighed.--results of the experiment.--the steam-vessel proceeds up the glommen.--he visits the great waterfall--passes into sweden.--has an interview with the crown prince of denmark, and afterwards with prince christian at copenhagen.--he visits professor oersted.--he proceeds to bremen to see dr. olbers.--returns to england.--his third paper read before the royal society.--voltaic influence of patches of rust.--a small quantity of fluid sufficient to complete the circuit.--he receives from the royal society the royal medal.--the progress of voltaic discovery reviewed.--the principle is of extensive application.--the author's researches into the cause of the solution of lead in spring water.--an account of the numerous trials of protectors.--failure of the plan.--report of the french on the state of the protected frigate la constance.--dr. revere's new plan of protection. every incident, however trifling, if it relates to a great scientific discovery, merits the attention of the historian. as it accidentally occurred to me, and to me alone, to witness the original experiment by which mr. faraday first condensed chlorine gas into a liquid, i shall here state the circumstances under which its liquefaction was effected. i had been invited to dine with sir humphry davy, on wednesday the th of march , for the purpose of meeting the reverend uriah tonkin, the heir of his early friend and benefactor of that name.[ ] on quitting my house for that purpose, i perceived that i had time to spare, and i accordingly called in my way at the royal institution. upon descending into the laboratory, i found mr. faraday engaged in experiments on chlorine and its hydrate in closed tubes. it appeared to me that the tube in which he was operating upon this substance contained some oily matter, and i rallied him upon the carelessness of employing soiled vessels. mr. faraday, upon inspecting the tube, acknowledged the justness of my remark, and expressed his surprise at the circumstance. in consequence of which, he immediately proceeded to file off the sealed end; when, to our great astonishment, the contents suddenly exploded, and the oily matter vanished! [ ] sir humphry had expressed to me, on the preceding thursday, at the royal society, his wish to purchase the old house in penzance, which, as the reader will remember, was the early scene of his chemical operations; and, at his request, i conversed with mr. tonkin upon the subject; but it immediately appeared that the interest which the corporation of penzance possessed in the estate presented an insurmountable obstacle to the accomplishment of his object. mr. faraday was completely at a loss to explain the occurrence, and proceeded to repeat the experiment with a view to its elucidation. i was unable, however, to remain and witness the result. upon mentioning the circumstance to sir humphry davy after dinner, he appeared much surprised; and after a few moments of apparent abstraction, he said, "i shall enquire about this experiment to-morrow." early on the next morning, i received from mr. faraday the following laconic note: dear sir, the _oil_ you noticed yesterday turns out to be liquid chlorine. yours faithfully, m. faraday. it is well known that, before the year , the solid substance obtained by exposing chlorine, as usually procured, to a low temperature, was considered as the gas itself reduced into that form: sir humphry davy, however, corrected this error, and first showed it to be a hydrate, the pure gas not being condensable even at a temperature of- ° fahrenheit. mr. faraday had taken advantage of the cold season to procure crystals of this hydrate, and was proceeding in its analysis,[ ] when sir humphry davy suggested to him the expediency of observing what would happen if it were heated in a close vessel; but this suggestion was made in consequence of the inspection of results already obtained by mr. faraday, and which must have led him to the experiment in question, had he never communicated with sir humphry davy upon the subject. this avowal is honestly due to mr. faraday. [ ] the results are contained in a short paper in the quarterly journal of science, vol. xv. on exposing the hydrate, in a tube hermetically sealed, to a temperature of °, the substance fused, the tube became filled with a bright yellow atmosphere, and, on examination, was found to contain two fluid substances: the one, about three-fourths of the whole, was of a faint yellow colour, having very much the appearance of water; the remaining fourth was a heavy, bright yellow fluid, lying at the bottom of the former, without any apparent tendency to mix with it. by operating on the hydrate in a bent tube hermetically sealed, mr. faraday found it easy, after decomposing it by a heat of °, to distil the yellow fluid to one end of the tube, and thus to separate it from the remaining portion. if the tube were now cut in the middle, the parts flew asunder, as if with an explosion, the whole of the yellow portion disappeared, and there was a powerful atmosphere of chlorine produced; the pale portion, on the contrary, remained, and when examined, proved to be a weak solution of chlorine in water, with a little muriatic acid, probably from the impurity of the hydrate used. when that end of the tube in which the yellow fluid lay was broken under a jar of water, there was an immediate production of chlorine gas. after several conjectures as to the nature of the changes thus produced, mr. faraday arrived at its true explanation; viz. that the chlorine had been entirely separated from the water by the heat, and condensed into a dry fluid by the mere pressure of its own abundant vapour. he subsequently confirmed these views by condensing chlorine in a long tube, by mechanical pressure, applied by means of a condensing syringe, and which farther enabled him to ascertain that the degree of pressure necessary for this effect was about that of four atmospheres. to mr. faraday's paper upon this subject, published in the philosophical transactions for the year , sir humphry davy thought proper to add a "note on the condensation of muriatic acid gas into the liquid form." the circumstances under which this was effected are briefly these. on the morning (thursday, march th,) after mr. faraday had condensed chlorine, sir humphry davy had no sooner witnessed the result, than he called for a strong glass tube, and, having placed in it a quantity of muriate of ammonia and sulphuric acid, and then sealed the end, he caused them to act upon each other, and thus condensed the muriatic acid, which was evolved, into a liquid. the condensation of carbonic acid gas, nitrous oxide gas, and several others, were in succession treated with similar success; but, as i regard the discovery as strictly belonging to mr. faraday, i shall confine myself to the relation of those experiments and deductions which, with equal justice, i must assign to sir humphry davy. he observes, "that the generation of elastic substances in close vessels, either with or without heat, offers much more powerful means of approximating their molecules than those dependent upon the application of cold, whether natural or artificial: for, as gases diminish only about / in volume for every--degree of fahrenheit's scale, beginning at ordinary temperatures, a very slight condensation only can be produced by the most powerful freezing mixtures, not half as much as would result from the application of a strong flame to one part of a glass tube, the other part being of ordinary temperature: and when attempts are made to condense gases into liquids by sudden mechanical compression, the heat, instantly generated, presents a formidable obstacle to the success of the experiment; whereas, in the compression resulting from their slow generation in close vessels, if the process be conducted with common precautions, there is no source of difficulty or danger; and it may be easily assisted by artificial cold in cases when gases approach near to that point of compression and temperature at which they become vapours." on the th of april , he communicated to the royal society a paper "on the application of liquids formed by the condensation of gases as mechanical agents." he states that doubts may, for various philosophical reasons, exist as to the economical results to be obtained by employing the steam of water under great pressures, and at very elevated temperatures; but that no doubts can arise with respect to the use of such liquids as require for their existence even a compression equal to that of the weight of thirty or forty atmospheres; and where common temperatures, or slight elevations of them, are sufficient to produce an immense elastic force; and when the principal question to be discussed is, whether the effect of mechanical motion is to be most easily produced by an increase or diminution of heat by artificial means. with the assistance of mr. faraday, he made several experiments on the differences between the increase of elastic force in gases under high and low pressures, by similar increments of temperature. in an experiment made with carbonic acid, its force was found to be nearly equal to that of air compressed to one-twentieth at ° fah. and of air compressed to one-thirty-sixth at degrees, making an increase equal to the weight of thirteen atmospheres by an increase of twenty of temperature! in applying, however, the condensed gases as mechanical agents, davy admits that there will be some difficulty; "the materials of the apparatus must be as strong and as perfectly joined as those used by mr. perkins in his high-pressure steam-engine: but the small differences of temperature to produce an elastic force equal to the pressure of many atmospheres, will render the risk of explosion extremely small;" and he adds, "that if future experiments should realize the views here developed, the mere difference of temperature between sunshine and shade, and air and water, or the effects of evaporation from a moist surface, will be sufficient to produce results, which have hitherto been obtained only by a great expenditure of fuel." if this be true, who can say that future generations shall not perform their voyages in _gas_-vessels, across the atlantic ocean, with no other fuel than that which a common taper may supply? i fear, however, that in this scientific reverie, davy merely looked at the difference of the sensible temperatures, and entirely neglected, in his calculation, the quantity of heat rendered latent during the change of the liquid into the gaseous state; and which, perhaps, is far more considerable in the application of these fluids than in that of water; but even in this latter case, the great expenditure of heat in working the steam-engine, is in the portion rendered latent, and which cannot, by any contrivance, be brought again into operation, after it has performed its duty. that a philosopher who had, during the whole progress of his researches, directed such unremitting attention to the subject of heat, should have wholly overlooked an objection arising out of one of its most familiar phenomena, is scarcely less extraordinary than his having, on another occasion,[ ] advanced to a conclusion in direct opposition to the very principle of electricity, which his own discoveries had established. [ ] i here allude to an anecdote related by mr. babbage, in his "reflections on the decline of science in england;" a work, by the by, which strongly reminds me of a practical bull. a gentleman, anxious to escape the tax on armorial bearings, wrote a long letter to the commissioners, stating i do not know how many reasons to show that he could never have used them; and, after all, sealed the letter with his own coat of arms! had mr. babbage hoped to convince the reader that science was actually on the decline in this country, he should never have written a work which gives the lie to the title-page. now for the anecdote.--"meeting dr. wollaston one morning in the shop of a bookseller, i proposed this question: if two volumes of hydrogen and one of oxygen are mixed together in a vessel, and if by mechanical pressure they can be so condensed as to become of the same specific gravity of water, will the gases, under these circumstances, unite and form water? 'what do you think they will do?' said dr. w. i replied, that i should rather expect they would unite. 'i see no reason to suppose it,' said he. i then enquired whether he thought the experiment worth making. he answered, that he did not, for that he should think it would certainly _not_ succeed. "a few days after, i proposed the same question to sir humphry davy. he at once said, 'they will become water of course:' and on my enquiring whether he thought the experiment worth making, he observed that it was a good experiment, but one which it was hardly necessary to make, as it must succeed. "these were off-hand answers, which it might perhaps be hardly fair to have recorded, had they been of persons of less eminent talent; and it adds to the curiosity of the circumstance to mention, that i believe dr. wollaston's reason for supposing no union would take place, arose from the nature of the electrical relations of the two gases remaining unchanged: an objection which did not weigh with the philosopher whose discoveries had given birth to it." davy succeeded in liquefying gases by a method which, at first view, appears very paradoxical--_by the application of heat!_ the method consists in placing them in one leg of a bent sealed tube, confined by mercury, and applying heat to ether, or alcohol, or water, in the other end. in this manner, by the pressure of the vapour of ether, he liquefied prussic gas and sulphurous acid gas; which gases, on being reproduced, occasioned cold. there can be little doubt, he thinks, that these general facts of the condensation of the gases will have many practical applications. they offer, for instance, easy methods of impregnating liquids with carbonic acid and other gases, without mechanical pressure. they afford means of producing great diminutions of temperature, by the rapidity with which large quantities of liquids may be rendered aëriform; and as compression occasions similar effects to cold, in preventing the formation of elastic substances, there is great reason to believe that it may be successfully employed for the preservation of animal and vegetable substances for the purposes of food. davy might also have added, that the same general views will explain natural and other phenomena not previously understood. they certainly afford a plausible explanation of the nature of _blowers_ in coal-mines; and they may lead to more satisfactory views on other subjects of geology. they assign a limit to the expansive force of gas under increasing pressure, and account for effects connected with the _blasting_ of rocks, which would otherwise appear anomalous.[ ] [ ] in the year , mr. babbage attempted to ascertain whether pressure would prevent decomposition: for this purpose, a hole about thirty inches deep, and two inches in diameter, was bored downward into a limestone rock, into which was then poured a quantity of strong muriatic acid, and a conical wooden plug, that had been previously soaked in tallow, was immediately driven hard into the mouth of the hole. it was expected either that the decomposition would be prevented, or that the gas developed would split the rock by its expansive force: but nothing happened. now, it is most probable that a part of the carbonic acid had condensed into a liquid, and thus prevented that developement of power which mr. babbage had expected would have torn the rock asunder. it may be stated, greatly to the honour of davy, that there never occurred any question of scientific interest or difficulty in which he did not cheerfully offer his advice and assistance. few presidents of the royal society have ever exerted their influence and talents with so much unaffected zeal for the promotion of scientific objects, and for the welfare of scientific men. in the year , the great hafod copper-works, in the neighbourhood of swansea, were indicted for a nuisance, in consequence of the alleged destructive effects of the fumes which arose during the smelting of the ores. when we learn that the amount of wages paid by the proprietors of the works in this district exceeds , _l._, per annum; that twelve thousand persons, at least, derive their support from the smelting establishments; that a sum of not less than , _l._ sterling is annually circulated in glamorganshire and the adjoining county, in consequence of their existence; that they pay to the collieries no less than from , _l._ to , _l._ per annum for coal; that one hundred and fifty vessels are employed in the conveyance of ore, and, supposing each upon an average to be manned by five seamen, that they give occupation to seven hundred and fifty mariners, a more serious calamity can scarcely be imagined than the stoppage of such works: we may therefore readily believe, that davy entered most ardently into the consideration of some plan by which the fumes might be prevented, and the alleged nuisance abated. through the kind attention of my friend mr. vivian, i am enabled to insert the following letters. to john henry vivian, esq. london, jan. , . my dear sir, as you expressed a wish that i should commit to writing those opinions which i mentioned in conversation, when i had the pleasure of visiting you at marino, after inspecting your furnaces and witnessing your experiments on the smoke arising from them, i lose no time in complying with your desire. it is evident that the copper ore cannot be properly calcined without a copious admission of air into the furnaces, which must cause the sulphurous acid gas formed in the calcination to be mixed with very large quantities of other elastic fluids, which presents great mechanical, as well as chemical difficulties to its condensation or decomposition. to persons acquainted with chemistry, a number of modes of effecting these objects are known. of condensation, for instance, by water, by the formation of sulphuric acid, by alkaline lixivia, by alkaline earths, &c. of decomposition, by hydrogen, by charcoal, by hydro-carbonous substances, and by metals; but to most of these methods there are serious and insurmountable objections, depending upon the diluted state of the acid gas, and the expenses required. to form sulphuric acid, or to decompose by charcoal or hydrogen, or to condense by alkaline lixivia, or by alkaline earths, from the nature of the works, and of the operations for which they were intended, i conceive impracticable except at an expense that could not be borne; and the only processes which remain to be discussed are those by hydro-carbonous substances, and by the action of water. there can be no doubt that the gas may be decomposed by the action of heated hydro-carbonous gases from the distillation of coal; but for this purpose there must be a new construction of the furnaces, and more than double, probably triple, the quantity of fuel would be required, supposing even the swansea coal to contain the common average of bitumen; and this method must be infinitely more expensive, and liable to many more objections, than the one you have so ingeniously employed--absorption by water. as water costs nothing, and as a supply is entirely in your power, the application of it offers comparatively few difficulties; and it has the great advantage of freeing the smoke from fluoric and arsenious compounds, which would not be perfectly effected by any other method. the experiments of mm. phillips and faraday prove, that your shower baths have already entirely destroyed all the fluoric and arsenious fumes of the smoke, and by a _certain_ quantity of water, the smoke may undoubtedly be entirely freed from sulphurous acid gas. this, _your own_ plan, is the one that i strongly recommend to you to proceed with, and, if necessary, to extend. perhaps you may find an additional shower bath near the colder part of the flue useful. i have no idea that steam passed into the hot part of the flue can be of the least service; but if passed out with the smoke through the stack, it may tend to convert such residual portion of sulphurous acid gas, exposed to fresh air, into sulphuric acid. could you not likewise try a stream of _cold_ water passing along the bottom of the horizontal flue?[ ] i do not think the advantages of your improvements can be fairly appreciated, till the effects of your smoke are determined by actual experiments and fair trials. yours, &c. h. davy. [ ] for the purpose of acting by its cooling power in condensing vapour, which would carry down sulphurous acid with it. it would likewise assist by direct absorption. h. d. to the same. london, may , . my dear sir, i return you my thanks for the copies you were so good as to send me of your work on the modes you have adopted for rendering copper smoke innoxious, &c. i have read it with very great pleasure, and i am sure there can be but one feeling, and that of strong admiration, at the exertions you have made, and the resources you have displayed, in subduing the principal evils of one of our most important national manufactures. i trust you will have no more trouble on this subject, and that it will only occur to you in an agreeable form, with the high approbation as well as grateful feelings of your neighbours; and that your example will be followed. a committee of the royal society has been formed for investigating the causes of the decay of copper sheeting in the navy, as i mentioned to you. the navy board has sent us a number of specimens of copper in different stages of decay. we have our first meeting to examine them on thursday, and i shall have much pleasure in communicating to you our results. i wish i could do it in person. i am going into hampshire on sunday next to fish near fordingbridge for a week, and to try the avon and its tributary streams. i was going to give you an account of some experiments which mr. faraday has made by my directions in generating gases in close vessels as liquids, but i find i have not time. i have already found an application of this discovery, which i hope will supersede _steam_, as a difference of a few degrees of temperature gives the elastic force of many atmospheres. hoping to see you soon, i am, with best respects to mrs. vivian, and love to the charming little bessy, my dear sir, yours sincerely obliged, h. davy. * * * * * i proceed now to relate the history of an elaborate experimental enquiry, instituted for the purpose of ascertaining the chemical nature and causes of the well-known corrosive action of sea-water upon metallic copper; in order, if possible, to obviate that serious evil in naval economy--the rapid decay of the copper sheathing on the bottoms of our ships. an investigation which sir humphry davy commenced in the year , and prosecuted with his characteristic zeal and happy talent during a considerable period; when, at length, paradoxical as it may appear, the truth of his theory was completely established by the failure of his remedy! from the several original documents which have been placed at my disposal, and from the valuable communications and kind assistance of my friend mr. knowles, i trust i shall be enabled to offer to the scientific reader a more complete and circumstantial history of this admirable enquiry than has been hitherto presented to the public. the results he produced are equally interesting and important, whether we contemplate them biographically, as indicative of the peculiar genius by which they were obtained; or, scientifically, in their connexion with the electro-chemical theory, to the farther developement and illustration of which they have so powerfully contributed; or, economically, as the probable means by which the hand of time may be averted, an increased durability imparted to rapidly perishable works of art, and monuments of human genius transmitted to posterity, in all their freshness, through a long succession of ages. it is probable that, in the earliest period of naval architecture, some expedient[ ] was practised, in order to protect ships' bottoms from the ravages of marine worms.[ ] the use of metallic sheathing, however, is of ancient date. the galley supposed to have belonged to the emperor trajan was sheathed with sheets of lead, which were fastened with copper nails.[ ] the same metal was also used in the earlier periods of our naval history;[ ] and it is worthy of remark, that the circumstances which led to its disuse, were the rapid corrosion of the _rother irons_, (from the formation of a voltaic circle,) and the accumulation of sea-weed. [ ] mr. knowles, in his "inquiry into the means which have been taken to preserve the british navy," observes, that the first sheathing was probably the hides of animals covered with pitch, or with asphaltum, which led to the use of thin boards, having, in some cases, lime, and in others lime and hair, between them and the bottom of the ships. [ ] the worms infesting the timber of ships are--the _teredo_, the _lepisma_, and the _pholas_. the first of these, however, which was imported from india, is by far the most destructive; and i am informed by mr. knowles, that it is more abundant at plymouth than on any other part of the coast where there is a dock-yard; and although on the shores of england it is not of a very large size, yet it is a formidable enemy to the safety of those ships which have not a metallic sheathing to cover their bottoms. in the east indies, and off the coast of africa, the _teredo_ is of very large size; and holes have been bored by them in the timber of at least seven-eighths of an inch in diameter. [ ] alberti archeti. [ ] in the year , an act of parliament was passed, granting unto sir philip howard and francis watson, esq. the sole use of the manufacture of milled lead for sheathing ships; and, in the year , twenty ships had been sheathed with lead, manufactured by them, and which was fastened with copper nails.--see _knowles's inquiry_. in the year , copper plates were first used as sheathing on the alarm frigate, of thirty-two guns;[ ] a second underwent this operation in , a third in , four in , nine in ; and, in the course of the three following years, the whole british navy was coppered: an event which may be considered as forming an important era in the naval annals of the country. [ ] the copper sheathing was removed from this ship in , when all the iron was found to be much corroded, the pintles and braces nearly eaten through, and the false keel lost, from the decay of the keel staples and the bolt fastenings. thus, in the very first coppered ship, the voltaic effect, produced by the contact of copper and iron, was displayed in a very striking manner. the expense attending the use of copper for this purpose, in consequence of its corrosion and decay by salt-water, has always been felt as a serious objection to its use, and various suggestions have from time to time occurred, and numerous experiments been made, in the hope of obviating the evil,[ ] but without any great degree of success. [ ] an experiment was tried by painting or varnishing their inner surfaces, but the use of brown paper which has been dipped in tar, and placed between the wood and copper, is now considered to be the best mode. a solution of caoutchouc spread on paper was tried on the bottom of sir w. curtis's yacht; but, on examination, it was pronounced to be less efficacious than tarred paper. the solution of the metal, however, has been found to vary in degree at different anchorages: at sheerness, for instance, its rapidity is very great, in consequence of the copper being subjected to the alternate action of the sea, which flows in there from the british channel, and to the flux of water down the two great rivers, the thames and medway, loaded, as they necessarily must be, with the products of animal and vegetable decomposition. in order, if possible, to obtain a remedy for this evil, the naval departments of the government requested, in the latter part of the year , the advice of the president and council of the royal society, as to the best mode of manufacturing copper sheets, or of preserving them, while in use, against the corrosive effects of oxidation. sir h. davy charged himself with this enquiry; the results of which he communicated to the royal society, in three elaborate memoirs. the first was read on the nd of january ; the second, on the th of june, in the same year; and the third, and concluding paper, on the th of june . a very general belief prevailed, that sea-water had little or no action on _pure_ copper, and that the rapid decay of that metal on certain ships was owing to its impurity. on submitting, however, various specimens of copper to the action of the sea-water, sir h. davy came to a conclusion, in direct opposition to such an opinion;[ ] and mr. knowles informed me, in a late conversation upon the subject, that the attempts to purify the metal, since the government has manufactured its own copper sheathing, has been the cause of its more rapid decay. it will however presently appear, that the relative durability of the metallic sheets must also be influenced by circumstances wholly independent of their quality, some of which are very probably, even in our present advanced state of chemical knowledge, not thoroughly understood. [ ] in two instances, the copper (from the batavier and from the plymouth yacht) which had remained perfect for twenty-seven years, was found to be alloyed. in the former one there was an alloy of one three-hundredth part of zinc; and, in the latter, the same proportion of tin. on the other hand, in the case of the copper on the tartar's bottom, which was nearly destroyed in four years, upon being submitted to chemical examination by mr. phillips, it was found to be very pure copper. alloys of copper have generally been found more durable than the unmixed metal; and various patents have been taken out for the fabrication of such compounds; but metallic sheets so composed have been found to be too hard and brittle, and not to admit of that flexibility which is necessary for their application to a curved surface; the consequence of which has been, that they have cracked upon the ship's bottom. sir h. davy, on entering upon the examination of this subject, very justly considered, that to ascertain the exact nature of the chemical changes which take place in sea-water, by the agency of copper, ought to be the first step in the enquiry; for, unless the cause were thoroughly understood, how could the evil be remedied? on keeping a polished piece of copper in contact with sea-water, the following were the effects which successively presented themselves. in the course of two or three hours, the surface of the metal exhibited a yellow tarnish, and the water in which it was immersed contracted a cloudiness, the hue of which was at first white, but gradually became green. in less than a day, a bluish-green precipitate appeared, and constantly continued to accumulate in the bottom of the vessel; at the same time, the surface of the copper corroded, appearing red in the water, and grass-green where it was in contact with air. upon this grass-green matter carbonate of soda formed; and these changes continued until the water became much less saline. the green precipitate he ascertained to consist of an insoluble compound of copper, (which he thinks may be considered as a _hydrated sub-muriate_,) and hydrate of magnesia.[ ] [ ] the muriate of magnesia is the most active salt in sea-water. according to his own views of the nature of chlorine, he immediately perceived that neither soda nor magnesia could appear in sea-water by the action of a metal, unless in consequence of an absorption or transfer of oxygen, which in this case must either be derived from the atmosphere, or from the decomposition of water: his experiments determined that the former was the source which supplied it. by reasoning upon these phenomena, and applying for their explanation his electro-chemical theory, which had shown that chemical attractions may be exalted, modified, or destroyed, by changes in the electrical states of bodies, he was led to the discovery of a remedy for the corrosion of copper, by the very principle which enabled him, sixteen years before, to decompose the fixed alkalies. when he considered that copper is but weakly positive in the electro-chemical scale, and that it can only act upon sea-water when in a positive state, it immediately occurred to him that, if it could be rendered slightly negative, the corroding action of sea-water upon it would be null. but how was this to be effected? at first, he thought of using a voltaic battery; but this could hardly be applicable in practice. he next thought of the contact of zinc, tin, or iron; but he was prevented for some time from trying this, by the recollection that the copper in the voltaic battery, as well as the zinc, was dissolved by the action of dilute nitric acid; and by the fear, that too large a mass of oxidable metal would be required to produce decisive results. after reflecting, however, on the slow and weak action of sea-water on copper, and the small difference which must exist between their electrical powers; and knowing that a very feeble chemical action would be destroyed by a very feeble electrical force, he was encouraged to proceed; and the results were highly satisfactory and conclusive. a piece of zinc, not larger than a pea, or the point of a small iron nail, was found fully adequate to preserve forty or fifty square inches of copper,--and this, wherever it was placed, whether at the top, bottom, or in the middle of the sheet of copper, and whether the copper was straight or bent, or made into coils. and where the connexion between the different pieces of copper was completed by wires, or thin filaments of the fortieth or fiftieth of an inch in diameter, the effect was the same; every side, every surface, every particle of the copper, remained bright; whilst the iron, or the zinc, was slowly corroded. a piece of thick sheet copper, containing on both sides about sixty square inches, was cut in such a manner as to form seven divisions, connected only by the smallest filaments that could be left, and a mass of zinc, of the fifth of an inch in diameter, was soldered to the upper division. the whole was plunged under sea-water; the copper remained perfectly polished. the same experiment was repeated with iron, and after the lapse of a month, the copper was in both instances found as bright as when it was first introduced; whilst similar pieces of copper, undefended, underwent in the same water very considerable corrosion, and produced a large quantity of green deposit in the bottom of the vessel. numerous other experiments were performed, and with results equally conclusive of the truth of the theory which had suggested them. there was however one point which still remained for enquiry. as the ocean may be considered in its relation to the quantity of copper in a ship, as an infinitely extended conductor, it became necessary to ascertain whether that circumstance would influence the results. for this purpose, he placed two very fine copper wires, one undefended, the other defended by a particle of zinc, in a very large vessel of sea-water, which water might be considered to bear the same relation to so minute a portion of metal, as the sea to the metallic sheathing of a ship. the result was perfectly satisfactory. the defended copper underwent no change; the undefended tarnished, and deposited a green powder.[ ] [ ] during the course of some experiments in which i have been lately engaged, a simple mode of exhibiting the principle of protection occurred to me, which, i believe, has not before been suggested; at least, i cannot find any notice of such an experiment. as i consider it admirably calculated for illustration, i will here describe it. let two slips of copper of equal size, the one protected with a piece of zinc, the other unprotected, be plunged into two wine-glasses filled with a solution of ammonia. in a short time, the liquor containing the unprotected copper will assume an intensely blue colour; the other will remain colourless for any length of time. the theory is obvious. when metallic copper is placed in contact with an ammoniacal solution, a protoxide of the metal is formed which is colourless,--and will remain so, if the contact of air be prevented; but on exposure to the atmosphere, it passes into a state of peroxide, which is dissolved by the ammonia, and produces an intensely blue solution. in the case of the protected copper, the metal is incapable of attracting a single atom of oxygen, in consequence of having been rendered negative by the zinc, and consequently no solution can take place. davy having thus satisfied his own mind as to the truth of his views, communicated to government, in january , the important fact of his having discovered a remedy for the evil of which they had complained; and that the corrosion of the copper sheathing of his majesty's ships might be prevented by rendering the copper electro-positive, by means of the contact of tin, zinc, lead, iron, or any other easily oxidable metal; and that he was prepared to carry his plan into effect. a proposition from a philosopher of such known science, and upon a subject of such great importance to the navigation and commerce of the country, immediately obtained all the attention it deserved; and an order was made that the plan of protection should, under the superintendence of sir h. davy, be forthwith tried upon the bottom of a sailing cutter. to give to his discovery farther publicity, sir humphry requested that three models of ships might be exhibited in the spacious hall of the navy office in somerset house; the copper of one of which he proposed should be protected by bands of zinc, that of another by plates of wrought iron soldered on the sheathing, while the third should have its copper exposed without any protection whatever. these models were floated in sea-water for several months; and the experiment fully confirmed the results he had previously obtained in his laboratory. the models were from time to time examined by persons of the highest scientific character, as well as by others of great naval celebrity; and so alluring was the theory, and so conclusive the experiments, that, instead of waiting the result of the slow but more certain ordeal to which the plan had been submitted, it was immediately put into extensive practice, both in the government service and on the bottoms of ships belonging to private individuals. to those the least acquainted with the principles of voltaic action, it was only necessary to state the proposition, in order to command their assent to its truth. the utility of the plan therefore was never questioned, but the claims of davy to the originality of the invention were doomed to meet with immediate opposition.[ ] [ ] amongst other counter-claims, there appeared, in a weekly publication entitled "the mechanic's magazine," a statement in favour of a person of the name of wyatt, founded on the following advertisement in "the world" newspaper of april , . "by the king's patent, tinned copper sheets and pipes manufactured and sold by charles wyatt of birmingham. these sheets, amongst other advantages, are particularly recommended for sheathing of ships, as they possess all the good properties of copper, with others obviously superior." it is unnecessary to observe that, except their object, there is nothing in common in the inventions of davy and wyatt. the superiority claimed by wyatt consisted merely in coating the copper with some substance less corrosive by sea-water than that metal: an idea borrowed from the common practice of tinning copper vessels. the correctness of the principle having been established, it became, in the next place, necessary to determine the most eligible metal to be used for protection; the proportion which it must bear to the surface of the copper-sheathing below the waterline; the form least likely to offer resistance to the sea, and to impede the sailing of the vessel; and lastly, its most convenient position on the ship's bottom. to ascertain these several points, lord melville and the lords of the admiralty desired the commissioners of the navy board, and of the dock-yards, to afford sir humphry every assistance and facility for prosecuting the necessary experiments; and he accordingly made many very extensive trials, not only on copper sheets which were immersed in the sea, but also on the bottoms of a considerable number of boats which had been coppered for that purpose, and exposed to the flow of the tide in portsmouth harbour; upon which occasions he varied the nature as well as the proportions of the protecting metal. the results were communicated to the royal society, and they constituted the materials for his second memoir on the subject. "when the metallic protector was from / to / parts of its surface, there was no corrosion nor decay of the copper; with smaller quantities, such as from / to / , the copper underwent a loss of weight, which was greater in proportion as the protector was smaller; and, as a proof of the universality of the principle, it was found that even / part of cast iron saved a certain proportion of the copper. "the sheeting of boats and ships, protected by the contact of zinc, or cast and malleable iron in different proportions, compared with those of similar boats and sides of ships unprotected, exhibited bright surfaces; whilst the unprotected copper underwent rapid corrosion, becoming first red, then green, and losing a part of its substance in scales. fortunately, in the course of these experiments, it was proved that cast iron, the substance which is cheapest and most easily procured, is likewise most fitted for the protection of the copper. it lasts longer than malleable iron, or zinc; and the plumbaginous substance which is left by the action of sea-water upon it, retains the original form of the iron, and does not impede the electrical action of the remaining metal." in the earlier stage of the investigation, it had been suggested by mr. knowles, and several other persons, that by rendering the copper innoxious, it was probable sea-weeds might adhere to the sheets; but this objection he answered by stating, that negative electricity could not be supposed favourable to animal and vegetable life; and as it occasioned the deposition of magnesia, a substance exceedingly noxious to land vegetables, upon the copper surface, he entertained no difficulty upon that subject: in this, however, he was fatally mistaken. he found, after a trial of several weeks, that the metallic surface became coated with carbonate of lime and magnesia, and that, under such circumstances, weeds adhered to the coatings, and marine insects collected upon them; but at the same time he observed, that when the proportion of cast iron, or zinc, was below / , the electrical power of the copper being less negative, no such deposition occurred; and that although the surface had undergone a slight degree of solution, it remained perfectly clean: a fact which he considered of great importance, as it pointed out the _limits of protection_; and makes the application of a _very small_ quantity of the oxidable metal more advantageous, in fact, than that of a larger one. during the course of these experiments, many singular facts occurred to him, which tended to confirm his views of electro-chemical action. amongst the various details which remained for his investigation, the relations between the surface of the protector, and that of the copper sheathing, under the different circumstances of temperature, saltness of the sea, and rapidity of the ship's motion, presented themselves as objects of great importance; and an opportunity occurred which enabled him to pursue them by actual observation and experiment. in the month of june , a steam-vessel, h.m. ship the comet, was, at the express request of the king of denmark, ordered to proceed to heligoland, for the purpose of fixing with precision, by means of numerous chronometers, the longitude of that island, in order to connect the danish with the british survey; and the board of longitude having recommended that the voyage should be extended as far as the naze of norway, for the purpose of ascertaining also the longitude of that important point, sir h. davy thought that this vessel would afford him the means of performing his desired experiments upon protected and unprotected copper sheets, when under the influence of rapid motion; and upon application to the board of admiralty, he obtained the entire disposal of the vessel after the required observations had been completed, as long as the season would allow her going to sea; and, that every facility might be afforded him, a skilful carpenter was put on board, to prepare whatever might be necessary for the prosecution of the enquiry. for the following account of his adventures upon this occasion i am indebted to dr. tiarks, who, in his character of astronomical observer, superintended the expedition. in the first instance, davy directed to be constructed a number of oblong, rectangular, thin plates of copper, the surface of which should exceed that of a square foot: in the centre of these plates was fastened a slip of copper, by means of which other pieces of copper, which had small plates of iron of various dimensions attached to them, were fixed to the plate, by merely sliding them into the groove thus prepared for their reception. the plates were all carefully weighed previously to the experiment, and the pieces of iron were considered as representing the various proportions of iron and copper surfaces within whose limits sir h. davy had been led, by former experiments, to expect that the best proportion would be found. these plates were afterwards slipped into wooden frames, and nailed to the ship's side, over a piece of thick canvass, for the purpose of intercepting every possible communication between them and the copper sheathing. it was proposed that, after each trip, these plates should be accurately weighed, in order to ascertain the loss which they severally might sustain from the corrosive action of the sea, while thus protected by different proportions of iron surface; and, to ensure every possible accuracy, he carried with him the excellent balance, constructed by ramsden, which is in possession of the royal society. sir h. davy, accompanied by lord clifton, embarked at greenwich on the th of june, and the vessel arrived at heligoland on the nd of july. here, as they remained not more than one day, the plates were not examined, although the master expressed strong doubts as to their safety. the vessel then proceeded, by order of sir humphry, to norway, a country which he was, for several reasons, very desirous of visiting, especially for the sake of determining a doubtful point in ornithology, upon which he subsequently corresponded with professor rheinhard, of copenhagen. the difference of longitude, also, between that country and greenwich, not having been accurately ascertained, offered perhaps an additional reason for thus deviating from a course which, it must be confessed, was at variance with the original plan of the expedition. after a severe gale of wind on the th of july, the vessel arrived, on the day following, at rleve, near mandal, and afterwards proceeded to this latter place, at which davy remained for several days, during which interval the vessel made a tour to the naze, and took in coal. on the arrival of the vessel in the port, the plates were immediately examined; but, to the great disappointment of sir humphry, it was discovered that every one of the protectors had been washed away, and that most of the plates had sustained considerable injury. with the country around mandal he was much pleased; for, although it is far from being fertile, the scenery is rendered exceedingly striking and beautiful by the numerous lakes which wash the feet of high and sometimes perpendicular mountains, at that time clothed with the rich verdure of their summer herbage. sir humphry made several excursions into the interior of the country, and derived much amusement from angling in the lakes; and had it not been from his own inspection of the roads, and the information which he collected respecting them, together with an indisposition of his fellow-traveller, lord clifton, he would have made an extensive land journey through the country; but, under the existing circumstances, he determined to return to england through denmark and germany. he therefore at once resolved to take the steam-boat with him as far as sweden, where the excellent roads would enable him, without inconvenience, to reach gottenburg, and thence to continue his route through denmark to germany. the vessel proceeded accordingly to christiansand, the chief town of a country of the same name. having been provided with some spare plates and protectors, he fixed them to the ship's side at mandal, as he was informed that the voyage could be entirely performed within the rocks, with which the whole coast of norway is so plentifully studded; but a short traverse through an open part of the sea, not far from mandal, again defeated his object. the protectors were washed away, and no result was obtained. at christiansand he remained a few days, in order to try some new plates, which were constructed there under his own inspection. upon this occasion he made an excursion to the falls of the torjedahl, distant about six miles from the town. the river abounds with salmon, which were easily caught in their descent from the falls, by an apparatus contrived for that purpose. sir humphry amused himself by teaching the inhabitants the operation of _crimping_, and he declared the flavour of the fish to be superior to any salmon he had ever tasted. it was at christiansand that he became acquainted with the norwegian race of ponies, so well adapted for mountainous countries; and which, at his recommendation, were afterwards introduced into england by mr. knight, of downton castle. from christiansand the vessel proceeded on her route eastward to arendal, where she arrived on the th, after a passage of only a few hours. the route lay entirely within the rocks,--and so narrow were the passages, that the vessel could frequently not pass the rocks on either side without touching them. at arendal, which is the chief place of a remarkable mining district, sir humphry was well received by the messrs. dedehamys, two brothers, and the leading merchants of the place, with whom he made several excursions to the neighbouring mines. he was also invited by them to meet at their beautiful country seats the most respectable inhabitants of the town. in the house of mr. dedehamy, davy was introduced into norwegian society, and, for the first time, had an opportunity of witnessing the customs and manners of the country. a short time before dinner, the guests were summoned to partake of pickled fish, anchovies, and smoked salmon, with rum, brandy, and wine, which were placed on small tables in the drawing-room in which the company assembled. this custom of taking salt provisions, together with spirits, just before dinner, is very general in the north, and is considered as the best means of preparing the stomach, and of provoking an appetite for the approaching meal. the very numerous party, which, with the exception of the hostess and her daughter, consisted entirely of men, were then ushered into two large rooms, one not being sufficiently spacious to accommodate them, and each person took his seat promiscuously. at the beginning of the dinner, large basins filled with sugar were carried round by the host's daughter, followed by a servant, from which each gentleman took a large handful. sir humphry, surprised at so singular a ceremony, enquired its meaning; when the host very good-humouredly answered, that in norway they thought, if the wine was good it could not be spoiled by sugar,--and if bad, that it would be improved by it. davy immediately followed the example of the company, and helped himself to the sugar. amongst the party present were several members of the diet (storthing), which had recently refused the applications of the king for various grants of money. this subject excited much animated conversation, and the majority of the persons present expressed their approbation at so bold and independent a measure. this called forth a political toast relating to the situation of their country; when the whole company, elated with wine and conversation, simultaneously burst forth into the national chorus of norway, which had been composed as a prize poem during the short struggle against the union of that country with sweden, and which was much admired by the norwegians, and on all occasions sung by them with the utmost enthusiasm of feeling; but, notwithstanding the liberal politics of the party, they drank sir humphry's toast--"the king of norway and sweden"--with much apparent loyalty. a succession of toasts followed, the last of which recommended "the british constitution as a model for all the world." with this sentiment the festivities concluded--a momentary silence ensued; the custom of the country assigned to a stranger the honourable office of returning to the host and hostess the thanks of the company for their hospitable reception; all eyes were anxiously fixed upon the english philosopher; and as soon as he was made acquainted with the duty he was expected to perform, he rose from his seat, and in allusion to the sentiment so recently drunk in compliment to himself, he proposed as a concluding toast, "norwegian hospitality a model for all the world." from arendal the vessel proceeded to laurvig, where she stopped only a few hours; but sir humphry seized this opportunity to go on shore to view the country, and he afterwards weighed the copper plates which had been attached to the ship in christiansand, as the vessel was now to cross that deep bay, at the bottom of which is situated christiana, the capital of the kingdom. the few plates were found to be in good order; and the results, which however must be allowed to have been very incomplete, confirmed, as far as they went, the conclusions to which he had been led by former experiments, viz. that / of iron surface was the proportion best calculated to defend the copper, without so overprotecting it as to favour the adhesion of marine productions; while they moreover proved that there is a mechanical as well as a chemical wear of the copper, which, in the most exposed part of the ship, and in the most rapid course, bears a relation to it of nearly to . . the country increased in fertility towards the eastern parts of it; but it possessed much less beauty than the neighbourhood of mandal. as soon as davy perceived that the vessel had to pass near the mouth of the glommen, the largest river of norway, he directed that she should enter it. steam-boats appeared to have been entirely unknown in that part of the country. the inhabitants of the town of frederickstadt were alarmed by the belief that the vessel was on fire, and they ran down to the beach in multitudes. as the vessel proceeded up the river, the people every where left their work, looked on awhile in silent amazement, and then shouted with delight. the vessel anchored a mile below the great fall of the glommen, called _sarpen_, and which davy visited on the following day (july ). three kings of denmark have visited this fall, and a name commemorates the spot whence they viewed this grand scene of nature. the fall is not one perpendicular descent, but consists of three sheets of water closely succeeding each other; and, by means of a barometer, he ascertained the entire altitude to be little more than a hundred feet. in comparing the character of this waterfall with those of the others he had visited, he observes, that size is merely comparative; and that he prefers the velino at terni, on account of the harmony that exists in all its parts. it displays all the force and power of the element, in its rapid and precipitous descent; and you feel that even man would be nothing in its waves, and would be dashed to pieces by its force. the whole scene is embraced at once by the eye, and the effect is almost as sublime as that of the glommen, where the river is at least one hundred times as large; for the glommen falls, as it were, from a whole valley upon a mountain of granite; and unless where you see the giant pines of norway, fifty or sixty feet in height, carried down by it and swimming in its whirlpools like straws, you have no idea of its magnitude and power. considering these waterfalls in all their relations, he is disposed to think, that while that of velino is the most perfect and beautiful, the fall of the glommen is the most awful. on both sides of this fall are extensive saw-mills, with machinery of very imperfect construction. davy spent some time with the proprietors of these mills, who were acquainted with the english language, and showed him every attention in their power. as an angler, he spoke with regret of the immense quantity of sawdust which floated in the water, and formed almost hills along the banks, and which, he observed, must be poisonous to the fish, by sometimes choking their gills, and interfering with their respiration. from the glommen the steam-vessel passed through the svinesund to strömstadt, the first town in sweden beyond the frontier of norway, from which charles xii. essayed to besiege the neighbouring fortress of frederickstadt in norway. from strömstadt, davy set out on the th of july, and reached gottenburg by land in two days, where he remained for a short time, in consequence of a slight indisposition. on his journey, he had a conversation with oscar, the crown prince of denmark, who, under the direction of berzelius, had diligently devoted himself to the study of chemistry. he conversed with our philosopher upon various subjects connected with that science; and davy, on his return to england, declared that he had never met with a more enlightened person. the crown prince expressed great surprise, as indeed did every body in sweden, on hearing that it was not davy's intention to visit professor berzelius at stockholm; and his astonishment was still farther increased, when he was informed by himself, that he came to norway and sweden with no other view than to enjoy the diversion of hunting and fishing! he however did by accident afterwards meet berzelius, but his interview was but of short duration. from gottenburg he hastened to copenhagen, where he renewed his acquaintance with prince christian of denmark, cousin of the king, and heir presumptive of the crown; in whose company he had some years before observed an eruption of mount vesuvius. he also visited professor oersted, and earnestly requested that he might see the apparatus by which that philosopher had made those electro-magnetic experiments which had rendered his name so celebrated throughout europe. he next proceeded to neuburg and altona, where he intended to re-embark for england in the steam-vessel which had, during the interval of his continental tour, made a voyage to england, and was again on her way to the elbe. at the suggestion, however, of professor schumacher, the astronomical professor at copenhagen, but residing at altona, in whose society he passed a great portion of his time, he accompanied that gentleman to bremen, in order to make the acquaintance of the venerable dr. olbers, who, since his retirement from an extensive medical practice, had entirely devoted his time to the pursuit of his favourite science astronomy; as well as to be introduced to professor gauss, of gottingen, who happened to be at that time carrying on his geodetical operations for the admeasurement of the kingdom of hanover. davy expressed a great desire to see the telescope with which dr. olbers had discovered the two planets, pallas and vesta, and which to his great surprise turned out to be a very ordinary instrument. his personal intercourse with these two celebrated philosophers appeared to afford him the highest satisfaction; and he spent two days most agreeably in their society. in his "salmonia," he gives us some account of his adventures as an angler during this short excursion to norway and sweden. "all the norwegian rivers," says he, "that i tried (and they were in the southern parts) contained salmon. i fished in the glommen, one of the largest rivers in europe; in the mandals, which appeared to me the best fitted for taking salmon; and in the arendal; but, though i saw salmon rise in these rivers, i never took a fish larger than a sea-trout; of these i always caught many--and even in the _fiords_, or small inland salt-water bays; but, i think, never any one more than a pound in weight. it is true that i was in norway in the beginning of july, in exceedingly bright weather, and when there was no night; for even at twelve o'clock the sky was so bright, that i read the smallest print in the columns of a newspaper. i was in sweden later--in august: i fished in the magnificent gotha, below that grand fall, trollhetta, which to see is worth a voyage from england; but i never raised there any fish worth taking. i caught, in this noble stream, a little trout about as long as my hand; and the only fish i got to eat at trollhetta was bream." he again embarked, on the th of august, on board the comet steam-vessel, which had ascended the weser as high as her draught of water would allow, and reached england, after a very boisterous passage, on the th of the same month; indeed, the vessel left the mouth of the weser with a contrary wind, and the pilot was unwilling to put to sea, but davy insisted on proceeding without delay. during the whole passage he suffered extremely from sea-sickness, and in a letter written to professor schumacher, shortly after landing, he remarks that "the sea is a glorious dominion, but a wretched habitation." * * * * * on the th of june , sir humphry read before the royal society his third and most elaborate paper upon copper sheathing, entitled "farther researches on the preservation of metals by electro-chemical means." in this memoir, he states it to be his belief, that there is nothing in the poisonous nature of the copper to prevent the adhesion of weeds and testaceous animals; for he observes, that they will readily adhere to the poisonous salts of lead which commonly form upon the metal protecting the fore-part of the keel; and even upon copper, provided it be in such a state of chemical combination as to be insoluble. it is then, in his opinion, the _solution_ of the metal--the _wear_ of its surface, by keeping it smooth, which prevents the adhesion of foreign matter. whenever the copper is unequally worn, deposits will, without doubt, rest in the rough parts, or depressions in the metal, and afford a soil or bed in which sea-weeds can fix their roots, and to which zoophytes and shell-fish can adhere; but there is another cause of foulness on the protected sheathing, arising from the deposit of earthy matter upon the copper, in consequence of its electro-negative condition. in relation to this subject, davy has offered some observations upon the effects produced by partial formations of rust, which appear to me to be exceedingly interesting and important. when copper has been applied to the bottom of a ship for a certain time, he says, a green coating, or rust, consisting of oxide, sub-muriate, and carbonate of copper, forms upon it; not equally throughout, but partially, and which, it is evident, must produce a _secondary_, partial, and unequal action, since those substances are negative with respect to metallic copper, and will consequently, by producing with it a voltaic circuit, occasion a more rapid corrosion of those parts still exposed to sea-water: from this cause, sheets are often found perforated with holes in one part, after having been used for five or six years; while in other parts they are comparatively sound.[ ] in like manner, the heads of the mixed metal nails, consisting of copper alloyed by a small quantity of tin, which are in common use in the navy, give rise to oxides that are negative with respect to the copper, so that the latter is often worn into deep and irregular cavities in their vicinity. [ ] the rusting of a common piece of iron, if carefully inspected, furnishes a beautiful illustration of this secondary action. the oxide, at first a mere speck, and formed perhaps by a globule of water, becomes negative with respect to the contiguous surface, and by thus forming a voltaic circuit, exalts its oxidability, and the rust consequently extends in a circle. a series of very interesting experiments, fully detailed in this memoir, which were instituted for the purpose of ascertaining the extent of the diminution of electrical action in instances of imperfect or irregular conducting surfaces, led him to the general conclusion, that a very small quantity of the imperfect or fluid conductor was sufficient to transmit the electrical power, or to complete the chain. this induced him to try whether copper, if nailed upon wood, and protected merely by zinc or iron on its _under_ surface, or on that next the wood, might not be defended from corrosion: a question of great practical moment with regard to the arrangement of protectors. for this purpose, he covered a piece of wood with small sheets of copper, a nail of zinc of about / part of the surface having been previously driven into the wood: the copper surface remained perfectly bright in sea-water for many weeks; and when the result was examined, it was found that the zinc had only suffered partial corrosion; that the wood was moist, and that, on the interior of the copper there was a considerable portion of revived zinc, so that the negative electricity, by its operation, provided materials for its future and constant excitement. in several trials of the same kind, iron was used with similar results; and in all these experiments there appeared to be this peculiarity in the appearance of the copper, that unless the protecting metal below was in a large mass, there were no depositions of calcareous or magnesian earths upon the metal; it was clean and bright, but never coated. the copper in these experiments was nailed sometimes upon paper, sometimes upon the mere wood, and sometimes upon linen; and the communication was partially interrupted between the external and internal surfaces by cement; but even one side or junction of a sheet seemed to allow sufficient communication between the moisture on the under surface and the sea-water without, to produce the electrical effect of preservation. this last experiment of davy is of greater importance than may at first appear, in showing what a small proportion of conducting fluid will complete a circuit, and in thus explaining phenomena, as i shall presently show, which might not otherwise be suspected to have an electrical origin. these results upon perfect and imperfect conductors led him to another enquiry, important as it relates to the practical application of the principle, namely, as to the extent and nature of the contact or relation between the copper and the preserving metal. he was unable to produce any protecting action of zinc or iron upon copper through the thinnest stratum of air, or the finest leaf of mica, or of dry paper; but the action of the metals did not seem to be much impaired by the ordinary coating of oxide or rust; nor was it destroyed when the finest bibulous, or _silver-paper_, as it is commonly called, was between them, being moistened with sea-water. he made an experiment with different folds of this paper. pieces of copper were covered with one, two, three, four, five, and six folds; and over them were placed pieces of zinc, which were fastened closely to them by thread; each piece of copper, thus protected, was exposed in a vessel of sea-water, so that the folds of paper were all moist. it was found in the case in which a single leaf of paper was between the zinc and the copper, there was no corrosion of the copper; in the case in which there were two leaves, there was a very slight effect; with three, the corrosion was distinct; and it increased, till with six folds the protecting power appeared to be lost; and in the case of the single leaf, the result differed only from that produced by immediate contact, in there not being any deposition of earthy matter. other experiments likewise proved that there was no absolute contact of the metals through the moist paper; for, although a thin plate of mica, as before stated, entirely destroyed the protecting effect of zinc, yet when a hole was made in it, so as to admit a very thin layer of moisture between the zinc and copper, the corrosion of the latter, though not prevented, was considerably diminished. the experimental part of this paper concludes with an account of various trials to determine the electro-chemical powers of metals in menstrua out of the contact, or to a certain extent removed from the contact of air; in order, if possible, to diminish the rapid waste of the protecting metals. in the progress of these experiments he exhibits, in a most beautiful manner, the singular effect of different proportions of a fixed alkali, when mixed with sea-water, in rendering the iron, in its voltaic connection with copper, more or less negative. he terminates the paper with some observations of a practical nature, relative to the best modes of rendering iron applicable to the purposes of protection; but, as these have been already embodied in the investigation, it is not necessary to notice them farther in this place. that i may give to the history of this subject all the perspicuity which it can derive from the connexion of its several parts, i shall now, in defiance of chronological order, proceed to consider his last bakerian lecture, "on the relations of electrical changes," which was read before the royal society, on the th of june . in which, after referring to his former papers on the chemical agencies of electricity, and the general laws of decomposition which were developed in them, he enters into some historical details respecting the origin and progress of electro-chemical science; being induced so to do, from a knowledge of the very erroneous statements which had been published upon the subject abroad, and repeated in this country. at the conclusion of this lecture, in reverting to the subject of voltaic protection, he says: "a great variety of experiments, made in different parts of the world, have proved the full efficacy of the electro-chemical means of preserving metals, particularly the copper sheathing of ships; but a hope i had once indulged, that the peculiar electrical state would prevent the adhesion of weeds or insects, has not been realized; protected ships have often indeed returned, after long voyages, perfectly bright,[ ] and cleaner than unprotected ships; yet this is not always the case; and though the _whole_ of the copper may be preserved from chemical solution in steam-vessels (from the rapidity of their motion) by these means,--yet they must be adopted in common ships only so as to preserve a portion,--so applied, as to suffer a certain solution of the copper;[ ] and an absolute remedy for adhesions is to be sought for by other more refined means of protection, and which appear to be indicated by these researches. [ ] the carnbrea castle, a large vessel, of upwards of six hundred and fifty tons, was furnished with four protectors, two on the stern, and two on the bow, equal together to about - th of the surface of copper. she had been protected more than twelve months, and had made the voyage to calcutta and back. she came into the river perfectly bright; and, when examined in the dry-dock, was found entirely free from any adhesion, and offered a beautiful and almost polished surface; and there seemed to be no greater wear of copper than could be accounted for from mechanical causes. [ ] a common cause of adhesions of weeds or shell-fish, is the oxide of iron formed and deposited round the protectors. in the only experiment in which zinc has been employed for this purpose in actual service, the ship returned after two voyages to the west indies, and one to quebec, perfectly clean. the experiment was made by mr. lawrence, of lombard street, who states that the rudder, which was not protected, had corroded in the usual manner. "the nails used in ships are an alloy of copper and tin, which i find to be slightly negative with respect to copper, and it is on these nails that the first adhesions uniformly take place: a slightly positive and slightly decomposable alloy would probably prevent this effect, and i have made some experiments favourable to the idea." he next proceeds to state some circumstances, in addition to those he had formerly noticed, by which the electrical relations of copper are altered. "i found," says he, "copper hardened by hammering, _negative_ to rolled copper;--copper (to use the technical language of manufacturers) both _over-poled_ and _under-poled_,[ ] containing, in one case, probably a little charcoal, and in the other a little oxide, _negative_ to pure copper. a specimen of brittle copper, put into my hands by mr. vivian, but in which no impurity could be detected, was negative with respect to soft copper. in general, very minute quantities of the oxidable metals render the alloy positive, unless it becomes harder, in which case it is generally negative." [ ] the _poling_ of copper is an operation, the theory of which is involved in a great deal of mystery. copper, when taken from the smelting furnace, is what is termed _dry_, that is, it is brittle, has an open grain and crystalline structure, and is of a purplish red colour. the following is the process by which it is refined, or _toughened_, by the process of _poling_. the surface of the melted metal in the furnace is, in the first place, covered with charcoal. a pole, commonly of birch, is then plunged into the liquid metal, which produces a considerable ebullition from the evolution of gaseous matter, and this operation is continued, fresh charcoal being occasionally added, so that the surface may be always kept covered, until the refiner judges from the assays that the metal is malleable. the delicacy of the operation consists in the difficulty of hitting the exact mark: if the surface should by accident be uncovered, it will return to its _dry_ state; and should the process be carried too far, it will be _over-poled_, by which the metal would be rendered even more brittle than when in a _dry_ state. when this is found to be the case, or, as they say, _gone too far_, the refiner directs the charcoal to be drawn off from the surface of the metal, and the copper to be exposed to the action of the air, by which means it is again brought back to its _proper pitch_, that is, become again malleable. now the question is, what are the changes thus produced in the copper? is the metal in its _dry_ state combined with a minute portion of oxygen, of which _poling_ deprives it, and thus renders it malleable? and does the _over-poling_ impart to it a minute portion of carbon, and is copper, like iron, thus rendered brittle both by oxygen and carbon? or, is the effect of the pole merely mechanical, that of closing the grain, and of altering the texture of the metal? something might be said in support of all these opinions. mr. faraday, who has attentively examined the subject, is unable to detect any chemical difference between _poled_ and _unpoled_ copper. on the other hand, when the metal is _over-poled_, it is found to oxidate more slowly, and its surface when in the furnace is so free from oxidation, that it is like a mirror, and reflects every brick in the roof. this certainly looks very much like carbonization.--see "an account of smelting copper, as conducted at the hafod copper-works; by j. h. vivian, esq."--_annals of philosophy_, vol. v. p. . these are important facts, and should dispose those who may preside over judicial enquiries, to pause before they infer the inferiority of copper sheeting from the rapidity of its decay.[ ]--i have now concluded a review of those admirable researches which led sir humphry davy to suggest and mature a plan for arresting the corrosion of the copper sheathing of vessels by voltaic action. mr. babbage has said that he was authorised in stating, that "this was regarded by laplace as the greatest of davy's discoveries." i do not think, however, that it should be considered in the light of a separate performance: we do injustice to the philosopher by regarding it as an independent and isolated discovery; for it was the result of a long series of enquiries, which commenced by establishing the laws of electro-chemistry,--which led him to the decomposition of the alkalies and earths,--suggested to his unwearied genius a succession of novel researches, in a new field of enquiry,--and concluded, as we have seen, in producing the most striking results by means of the greatest simplicity. not once during the progress of this enquiry had he any occasion to retrace his steps for the purpose of correction: justly has he observed in his last bakerian lecture, that, notwithstanding the various novel views which have been brought forward in this and other countries, and the great activity and extension of science, it is peculiarly satisfactory to find that he has nothing to alter in the fundamental theory laid down in his original communication; and which, after the lapse of twenty years, has continued, as it was in the beginning, the guide and foundation of all his researches. [ ] this observation was suggested by an examination of a late judgment of the court of common pleas, in the case of jones _v._ bright and others, on showing cause against rule for a new trial. this was an action brought by the plaintiff against the defendants for selling him copper, for the purpose of sheathing the ship isabella, which, from the rapidity of its corrosion, was inferred to have an inherent defect in its composition. in this case it was held, that with respect to _warranty_, there is a very wide difference as it applies to articles which are not the subject of manufacture, and those which are the produce of manufacture and of human industry. in the one case, it may be that no prudence, no care, could have guarded against a secret defect; in the other, by using due care, and providing proper materials, any defect in the manufacture may be guarded against. "in the case of the bowsprit, the man did not make the timber which composed the bowsprit; he merely cut it out, and fitted it to meet the purpose, and could therefore by no means have guarded against the rottenness in the centre of that bowsprit: but if a man makes copper, he may guard against inherent defects in that copper, by taking care that the copper contains a proper proportion of pure copper; and also by taking care that it is so well manufactured, that it does not drink in a greater quantity of oxygen than ought to be admitted into it, and that that oxygen, which of necessity gets in, (for some will,) shall be so distributed, that it shall not operate, as in the opinion of an intelligent witness the oxygen in this case did operate, by forming itself in patches, and thereby rendering it soft, and rendering the copper incapable of resisting the influence of salt-water--that he can guard against." with all due deference to the learned judge, suppose it be shown that no human wisdom can guard against those circumstances by which a portion of the copper surface may be rendered more highly electro-positive, what becomes of the judgment? that the decay of copper sheathing is effected by extrinsic causes, and does not necessarily depend upon an inherent defect in the metal, may be proved in numerous ways. if it were owing to the quality of the copper, why should five, ten, or twenty sheets out of a hundred, made from the same charge of metal in a furnace and manufactured under precisely similar circumstances, be affected, and the remainder be perfectly sound? why, again, should sheets, made from several distinct charges, placed on a particular vessel, be acted upon, while the same copper on other bottoms is not more than usually dissolved? did any inherent defect exist in the metal, it surely must have equally affected the whole batch. it is possible that, in some cases, in consequence of the sheets not having been properly cleansed before they are rolled, a portion of the oxide may be pressed into them by the rollers. in such a case, a voltaic effect might be produced, and portions of the metallic surface rendered more electro-positive. the president and council of the royal society appear to have been swayed by this consideration, when they adjudged to him "a royal medal,[ ] for his bakerian lecture on the relations of electrical changes, considered as the last link, in order of time, of the splendid chain of discoveries in chemical electricity, which have been continued for so many years of his valuable life." [ ] in the year , his majesty george iv. communicated to the royal society, through mr. peel, his intention to found two gold medals, of the value of fifty guineas each, to be awarded annually by the council of the royal society, in such a manner as shall, by the excitement of competition among men of science, seem best calculated to promote the object for which the royal society was instituted. thus had davy now received from the royal society all the honours they were capable of conferring upon him. in the year , they adjudged to him the medal on sir godfrey copley's donation for his various communications published in the philosophical transactions; in , they awarded him the rumford medals for his papers on combustion and flame; and in , upon the grounds just stated, the president and council expressed their unabated admiration by conferring upon him the only medal which remained for his acceptance--that which had been recently founded by their patron, his late majesty. having thus disposed of the speculative part of his admirable enquiry, it will be interesting to pause in our narrative, in order to take a philosophical review of the progress of voltaic discovery, in its relations to this particular object. it is a subject well calculated to afford a valuable lesson to the experimentalist, and at the same time to furnish illustrations, more striking even than that of the safety-lamp, of the necessity of that complicated species of machinery, without which the human mind is frequently unable to grapple with the simplicities of truth. it is true, that the fact of a galvanic effect being excited by the contact of two dissimilar metals was noticed in the earliest stages of the enquiry, but it is equally evident that the phenomena which attended it, and the laws by which it was directed, required for their discovery and elucidation the assistance of the voltaic battery. in reference to davy, it may be here repeated, that the power of obtaining simple results, through complicated means, was one of the most distinguishing features of his genius. it has been stated, that the alarm frigate, the first coppered ship in our navy, displayed very striking evidence of the effect of voltaic action, in the rapid corrosion of its iron.[ ] as early as , after copper sheathing had become general, the government issued orders that all the bolts under the line of fluitation should, in future, be of copper; but at that period, it was not possible that any idea could be entertained as to the true nature of the operation by which the iron was thus rapidly corroded, for it was only in the year that dr. ash noticed, for the first time, a phenomenon which was subsequently referred to the action of a simple voltaic circuit. [ ] numerous are the instances of later date which might be adduced in illustration of the same fact; and it is now generally supposed that it may have been a frequent cause of ships foundering at sea. by oxidation, the volume of the iron at first increases, and then diminishes; in consequence of which the ship leaks, or, to use a technical expression, becomes "_bolt sick_." when the salvador del mundo was docked at plymouth, in february , the iron fastenings were in such a state of corrosion, that five planks near the bilge dropped into the dock when the water left her. it is a very curious circumstance in the history of this subject, that, for many years after the voltaic influence had been recognised as the agent in metallic corrosion, so far from the existence of the accompanying phenomenon of preservation being suspected, it was even supposed that the metals mutually corroded each other. at so late a date as , we find davy himself, in the letter addressed to m. alavair, published in these memoirs,[ ] dwelling upon the necessity of avoiding metallic contact, in order to prevent _corrosion_, without throwing out the most distant hint as to the simultaneous production of a converse effect. [ ] page of this volume. the first distinct notice of a metal being preserved from oxidation by the contact of a dissimilar metal, is at once referred to a chemical law, without a reference even to its possible connection with voltaic action; and, striking as the fact may now appear, it never attracted much attention. m. proust observed, that although copper vessels be so imperfectly tinned, as to leave portions of the surface uncovered, still, in cooking utensils, we shall be equally protected from the poisonous effects of the former metal; because, says he, the superior readiness with which tin is oxidized and acted upon by acids, when compared with copper, will not allow this latter metal to appropriate to itself a single atom of oxygen.[ ] the same chemist observes, that if lead be associated with tin, it will be incapable of furnishing to acids any saturnine impregnation, since the latter, being more oxidable than the former, will exclusively dissolve, and thus prevent the former from being attacked. [ ] as far as the principle of voltaic protection goes, this may be very true; but it must be remembered that the acid generally present upon these occasions is acetic acid, which rises in distillation with water, so that at the boiling temperature it will be carried beyond the sphere of voltaic influence, and may thus act upon the denuded copper as much as though tin were not present. whether the principle of voltaic protection be applicable or not to the purpose of preserving copper sheathing, it is evident that it will suggest numerous other expedients of high importance in the arts, while it will explain phenomena previously unintelligible. by introducing a piece of zinc, or tin, into the iron boiler of the steam-engine, we may prevent the danger of explosion, which generally arises, especially where salt-water is used, as in those of steam-boats, from the wear of one part of the boiler. another important application is in the prevention of the wear of the paddles, or wheels, which are rapidly dissolved by salt-water. mr. pepys has also extended the principle for the preservation of steel instruments by guards of zinc: razors and lancets may be thus defended with perfect success. in the construction of monuments which are to transmit to posterity the record of important events, the artist will be careful in avoiding the contact of different metals: it is thus that the etruscan inscriptions, engraved upon pure lead, are preserved to the present day; while medals of mixed metals of a much more recent date are corroded. numerous are the facts daily presented before us, which receive from this principle a satisfactory explanation. to the philosopher, the examination of its agencies will furnish a perpetual source of instruction and amusement; and i will here enumerate a few simple instances of its effects: in the first place, for the purpose of showing that, whenever a principle or discovery involves or unfolds a law of nature, its applications are almost inexhaustible, and that, however abstracted it may appear, it is sooner or later employed for the common purposes of life; and in the next place, in the hope of convincing the reader, that there does not exist any source of pleasure so extensive and so permanent as that derived from the stores of philosophy. the saunterer stumbles over the stone that may cross his path, and vents only his vexation at the interruption; but to the philosopher there is not a body, animate or inanimate, with which he can come in contact, that does not yield its treasures at his approach, and contribute to extend the pleasures of his existence. i well remember some years ago, that, in passing through deptford, my curiosity was excited by the extraordinary brilliancy of a portion of the gilded sign of an inn in that town, while its other parts had entirely lost their metallic lustre. having obtained a ladder, i ascended to the sign, in order, if possible, to solve the problem that had so greatly interested me: the mystery immediately vanished; for an iron nail appeared in the centre of the spot, which had protected the copper leaf for several inches around it. any person may easily satisfy himself of the efficacy of such protection, in his rambles through the metropolis, by noticing the gilded, or rather coppered, sugar-loaves[ ] so commonly suspended over the shops of grocers, when he will frequently perceive that the parts into which the iron supports have entered, unless the latter have been painted, shine preeminently brilliant. if a still more familiar example of the effect of a simple voltaic circuit be required, it is afforded by the iron palisadoes, where the iron is constantly corroded at its point of contact with the lead by which it is cemented into the stone. these examples are not only interesting from their simplicity, but from their demonstrating the small quantity of a conducting fluid which is sufficient to transmit the electrical power, or to complete a simple circuit: a fact which, it will be remembered, the experiments of davy had before established.[ ] [ ] there is an excellent example at this time in the london road leading to the elephant-and-castle. [ ] page of this volume. as our knowledge advances, these principles will no doubt derive other illustrations, and be found capable of more extensive application; for as yet we are but in the infancy of the enquiry. i have lately been engaged in a series of experiments, the results of which, i confidently anticipate, will lead to some new facts connected with the changes produced on the negative metal of a voltaic circuit; an account of which i hope shortly to submit to the royal society. i shall on this occasion merely notice one result, which appears to me to admit of an immediate application to one of the most important circumstances of life--the purity of water contained in leaden cisterns. my attention has for several years been directed to the state of the water with which the metropolis is supplied; and upon having been lately requested to propose a remedy for preventing the action of a spring in the neighbourhood of london upon lead, which it had been found to corrode in a very rapid manner, i suggested the expediency of protecting the pipes and cisterns with surfaces of iron; but before such a plan was put in execution, i proposed to try its efficacy in the laboratory:--the first result was very startling; for, instead of preventing, as i had anticipated, i found that it greatly increased, the solution of the lead. after various experiments, i arrived at the conclusion, that lead, when rendered negative by iron, and placed in contact with weak saline solutions,--such, for instance, as common spring water,--was dissolved; in consequence of the decomposition of the salts and the transference of their elements according to the general law, the acid passing to the iron, and the alkali to the lead; and so powerfully is this latter body acted upon by an alkali, that, if a slip of it be immersed in a solution of potash or soda, its crystalline texture is so rapidly developed, that its surface exhibits an appearance similar to that presented by tin-plate, and which is designated by the term _moirée_. i apprehend that most of the anomalous cases of the solution of lead in common water, which have for so many years embarrassed the chemist, may thus receive an explanation. an eminent physician lately informed me, that some time since he was called upon to attend a family who had evidently suffered from the effects of saturnine poison, and that he well remembers there was an iron pump in the cistern that supplied the water. upon showing the results of my experiment to a no less eminent chemist, he was immediately reminded of a circumstance which occurred at islington, where the water was found to corrode the lead in which it was received: in this vessel there was an iron bar; and the fact would not have attracted his notice, nor have been impressed upon his recollection, but from the unusual state of corrosion in which it appeared. i shall conclude these observations by an account of "the change which some musket balls, taken out of shrapnell's shells, had undergone," by mr. faraday, and which is published in the th volume of the quarterly journal of science, for the year . this history is not only interesting on account of the high chemical character of its author, but satisfactory as being in direct opposition to previously established facts; and cannot therefore have received any bias from preconceived theory. "mr. marsh of woolwich gave me some musket balls, which had been taken out of shrapnell's shells. the shells had lain in the bottoms of ships, and probably had sea-water amongst them. when the bullets are put in, the aperture is merely closed by a common cork. these bullets were variously acted upon: some were affected only superficially, others more deeply, and some were entirely changed. the substance produced is hard and brittle; it splits on the ball, and presents an appearance like some hard varieties of hæmatite; its colour is brown, becoming, when heated, red; it fuses on platinum foil into a yellow flaky substance like litharge. powdered and boiled in water, no muriatic acid or lead was found in solution. it dissolved in nitric acid without leaving any residuum, and the solution gave very faint indications only of muriatic acid. it is a _protoxide of lead_, perhaps formed, in some way, by the galvanic action of the iron shell and the leaden ball, assisted probably by the sea-water. it would be very interesting to know the state of the shells in which a change like this has taken place to any extent. _it might have been expected, that as long as any iron remained, the lead would have been preserved in the metallic state._" in one experiment, i found that a piece of lead protected by iron underwent solution in water containing nitrate of potash, while it resisted the action of very dilute nitric acid: upon this point, however, farther enquiry is necessary; for i subsequently failed in producing the same effect, owing, no doubt, to having employed too strong an acid. let us return from this digression to the subject of sir humphry davy's protectors. it only remains for me to relate the results which followed the practical application of the voltaic principles which his various experiments had developed. in the month of may , directions were issued by the lords of the admiralty to protect, in future, the copper sheathing of all his majesty's ships which might be taken into dock, upon the plan proposed by sir humphry davy. the protectors were bars of iron six inches wide at their base, three inches in thickness in their centre, and, in outward form, the segment of an extended circle. they were usually placed on each side of the ship in a horizontal position, viz. in midships about three feet under water--on the keel in a line with these--and the remainder in the fore and afterparts of the ship (about three feet under the line of fluitation), as far forward and abaft as the curvatures of their respective bodies would allow of their lying flat upon the surface of the copper. as it is difficult by verbal description alone to convey a sufficiently distinct idea of this subject to persons unacquainted with naval architecture, i have introduced a sketch, exhibiting the _general_ position of the _protectors_, although they are necessarily exaggerated in size, or they would have appeared as mere specks upon the drawing. [illustration: a. a. line of fluitation.] on several ships, some of the protectors, in the stem and the stern, were placed _vertically_; in which case they were fastened to the stems and stern-posts; and in this manner they were found to act more powerfully in preserving the copper, than when they were all placed horizontally. the ends of the protectors were rounded, in order to prevent any great resistance to the water, and they were fastened to the bottoms of the ships with copper bolts, the iron being counter-sunk to receive their heads, and the holes were then filled with carbonate of lime, or parker's cement. to bring about the best possible contact of all the copper sheets, their edges, which lap over each other, where the nails are driven to fasten them to the ships, were rubbed bright, first with sand-paper, and finally with glass-paper. shortly after the ships thus protected were sent to sea, it was evident to all on board, from their dull sailing, that the bottoms had become very foul; and on being examined in dry docks, it was found that the copper was completely covered with sea-weed, shell-fish of various kinds, and myriads of small marine insects. upon their removal, however, it was found, on weighing the sheets, that the copper had suffered little or no loss; thus proving that, although its practical application had failed from unforeseen circumstances, the principle of protection was true, and had fully justified the expectation of its success. the copper near the protectors was much more foul than that at a greater distance from them; and there was, moreover, a considerable deposit of carbonate of lime, and of carbonate and hydrate of magnesia, in their vicinity. sir humphry davy immediately suggested, as a remedy for this evil, that the bottoms should be scraped, and the copper washed with a small quantity of acidulous water; and he also proposed that the protectors should in future be placed under, instead of over, the copper sheathing. this plan was immediately adopted. discs of cast-iron three and a half inches in diameter, and one-fourth of an inch in thickness, were let into the plank of the bottom of the glasgow, of fifty guns, on the starboard side only--the larboard side having been left without any protection. these discs were in the proportion of one to every four sheets of copper, and over them were placed pieces of brown paper, and over the paper thin sheet-lead, so that the latter metal was in contact with the copper sheathing. a similar experiment was also tried on the zebra, of eighteen guns, substituting, however, discs of zinc[ ] for those of iron. [ ] it would appear that davy latterly preferred zinc to iron, as the protecting metal. in a letter, dated october , addressed to a ship-owner, who had made some enquiries of him upon the subject, he says--"the rust of iron, if a ship is becalmed, seems to promote the adhesion of weeds; i should therefore always prefer pieces of zinc, which may be very much smaller, and which, in the cases i have heard of their being used, have had the best effect." the bottom of the glasgow was examined twelve months afterwards, when the discs of iron were found oxidated throughout, presenting in their appearance the characters of plumbago. the copper on the starboard side was preserved, but covered with weeds and shell-fish. the sheets on the larboard had undergone the usual waste, but were clean. the zebra was docked four years after the experiment had commenced, when the zinc protectors were perfect, and it did not appear that they had exerted any influence in preserving the copper, as it had wasted equally on both sides. it may be presumed in this case that the voltaic circuit had by some fault in the arrangement been interrupted. the apparent conversion of iron into a substance resembling plumbago, by the action of sea-water, has been frequently noticed. the protectors thus changed[ ] were, to a considerable depth from the surface, so soft as to be easily cut by a knife; but after being exposed for some time to the action of the atmosphere, they became harder, and even brittle. a portion of this soft substance having been wrapped in paper for the purpose of examination, and placed in the pocket of a shipwright, gave rise to a very curious and unexpected result: at first, the artist, like futitorious with his chestnuts, thought he perceived a genial warmth; but the effect was shortly less equivocal; the substance became hot, and presently passed into a state of absolute ignition. various theories have been suggested for its explanation: mr. daniell has advanced an opinion which supposes the formation of silicon, and thus accounts for the spontaneous ignition by the action of air. [ ] in the annals of philosophy (vol. v.) may be found a paper by dr. henry, on the conversion of cast iron pipes into plumbago. this change appears to have been effected by the action of water containing muriate of soda, and the muriates of lime and of magnesia. cast iron contains a considerable portion of carbon; the change is therefore readily explained on the supposition of the removal of the principal metallic part by these salts. the muriates of lime and magnesia have been observed by dr. henry to discharge writing ink from the labels of bottles, to which they had been accidentally applied; and the same ingenious chemist has been baffled in his attempts to restore the legibility of ink upon paper which had been exposed to sea-water. the texture of the paper was not injured, but the iron basis of the ink, as well as the gallic acid, was entirely removed. the disadvantages which arise from the foulness of ships' bottoms, particularly when on foreign stations, where there are no dry docks to receive them, are so serious, that the government was obliged, in july , to order the discontinuance of the protectors on all sea-going ships; but directed that they should still be used upon all those that were laid up in our ports. when, however, an examination of the latter took place, they were found to be much more foul than those which had been in motion at sea: shell-fish of various kinds had adhered to them so closely, that it was even necessary to use percussion to remove them, which not only indented the copper, but in many instances actually fractured it. under all these discouraging circumstances, the unwelcome conviction was forced upon the agents of government, that the plan was incapable of successful application, and it was accordingly altogether abandoned in september . such were the results of the experiments carried on in the ports of england, for the protection of copper sheathing, from the success of which sir h. davy justly expected honours, fame, and reward. that his disappointment was great, may be readily imagined, and it is supposed to have had a marked influence upon his future character. it is much to be regretted that his vexation should have been heightened by the unjust and bitter attacks made upon him by the periodical press, and by those subalterns in science, who, unable to appreciate the beauty of the principle he had so ably developed, saw only in its details an object for sarcasm, and in its failure an opportunity for censure; while those whose stations should have implied superior knowledge, in the pride and arrogance of assumed contempt, sought a refuge from the humiliation of ignorance. that davy was severely hurt by these attacks, is a fact well known to his friends. in a letter to mr. children he says: "a mind of much sensibility might be disgusted, and one might be induced to say, why should i labour for public objects, merely to meet abuse?--i am irritated by them more than i ought to be; but i am getting wiser every day--recollecting galileo, and the times when philosophers and public benefactors were burnt for their services." in another letter he alludes to the sycophancy of a chemical journal, which, after the grossest abuse, suddenly turned round, and disgusted him with its adulation. "i never shake hands," says he, "with chimney sweepers, even when in their may-day clothes, and when they call me '_your honour_.'" while the trials above related were proceeding in the ports of england, the naval department of france was prosecuting a similar enquiry; and as experiments of this nature are conducted with greater care, and examined with superior science, in that country, it may not be uninteresting to the english reader to receive a detail of the examination of the bottom of la constance frigate, in which the protectors bore a much larger proportion to the copper surface than was ever practised in the british navy. this document, i may observe, is now published for the first time. "the inspection of the bottom of the frigate la constance, has given rise to some interesting observations on the effect of protectors, and it has confirmed the fact before advanced of the great inconvenience which attends the application of too large a proportion of the protecting metal. "the surface of this metal, which was of cast iron, placed on each side of the keel, and in long scarphs of iron plates situated towards the stem and stern-post and the water line, appeared to have been about the - th part of the surface of the copper, instead of the - th part as now practised. "the galvanic action has been extreme, both in rapidity and intensity. the scarphs are entirely destroyed, and have absolutely disappeared; and we should have been ignorant of their having ever existed, had we not been informed of the fact, and observed dark stains which marked their position, and discovered the nails still entire by which they had been fastened. "the plates, which were in the first instance about three inches thick, were covered throughout their whole length by a thick, unequal coating, spotted with yellow oxide. this was principally owing to the absorption of about twenty-five per cent. of its weight of water. under this, the iron was as soft as plumbago, and there remained scarcely an inch of metal of its original metallic hardness. "the bulky and irregular appendage (the protectors) at the lower part of the ship's bottom caused a great noise in the sea, in consequence of the dead water which it occasioned, and doubtless lessened the speed of the vessel. but that which contributed most to this unfortunate result, was the exceedingly unclean state of the copper, arising from the excess of the iron employed: this, carried to so great an extent, having the effect of extracting matter from the water, which, forming a concretion on the sheets, enabled the marine animals the more easily to attach themselves. the sheathing was covered with a multitude of _lepas anatifera_, shells with five valves, suspended by a pedicle of three or four centimetres long, collected into groups; of _lepas tintinnabulum_, a shell with six valves; of oysters with _opercula_; of _polypi_, &c. no part of the bottom was free from them. "below, the copper was certainly preserved from oxidation; and up to within a few sheets of the water line, it did not appear to be worn. but to save expense, it was obliged to be cleansed without removal, by rubbing it hard with bricks and wet sand, which has succeeded very well in restoring its copper colour." the following is the description of shells above enumerated:-- genus _anatifa_, encyclopedia.--(_lepas_, linnæus.) [illustration: fig. .] fig. . smooth _anatifa_ (_lepas anatifera_, linn.)--shell consisting of five valves, of which two larger and two smaller ones are opposite to each other; and a fifth, which is narrow, is arched and rests upon the ends of the first four: these valves are not connected by any hinge; they are held together by the skin of the animal, which lines their interior and opens in front by a longitudinal separation. their colour is orange during the life of the animal. the base of the shell is united to a fleshy tube, tendinous, cylindrical, susceptible of contraction, saffron-coloured, becoming brown and black in drying. [illustration: fig. .] fig. . smooth _anatifa_, as seen from the other side, the pedicle dry and contracted. [illustration: fig. .] fig. . smooth _anatifa_, as seen in front, showing the longitudinal separation. genus _anomia_. [illustration] shell with valves, unequal, irregular, having an operculum; adhering by its operculum; valve usually pierced, flattened, having a cavity in the upper part; the other valve a little larger, concave, entire; operculum small, elliptical, bony, fixed on some foreign body, and to which the interior muscle of the animal is attached. [illustration] species, onion-peel _anomia_.--(_ephippium_, linn.) shell common, whitish and yellowish, found in the mediterranean and the ocean. besides the abovementioned species, which were found in large quantities, there were also some muscles and oysters.--(_mytilus afer. baccina._--linn. gmel. .) genus "_balane de blainville_." (_balanite_, encyclopedia.--_lepas_, linn.) [illustration: fig. .] fig. . tulip balanus.--(_lepas tintinnabulum_, linn.) shell with six unequal valves articulated by a scaly suture, of which the edges appear to be finely crenellated in the cavity; the form of the valves is conical, aperture ample, and nearly quadrangular. operculum composed of four triangular pieces crenellated and marked with very projecting transverse striæ, which appear to extend from the top to the bottom; the two posterior pieces are perpendicular, and are applied to the hinder partition of the cavity of the shell; they are terminated by two conical prolongations, of which the points are sharp and diverging. the two foremost pieces are placed in the aperture, in an oblique direction. the colour of this balanus from clear red to violet and brown. [illustration: fig. .] fig. . view of the upper part of the tulip balanus. [illustration: fig. .] fig. . view of the base. genus oyster, (_ostrea._) [illustration] species of oyster, nearly similar to the common oyster, (_ostrea edulis_,) and of the huître cuilier, (_ostrea cochlear_,) their shell rather fragile, almost without lamellæ; upper valve concave, colour rather deep violet, form variable. "besides these three kinds of molluscæ, of which the number was considerable, several species of calcareous polypi were found; but those which could be obtained were too imperfect to allow of their being correctly described. "the iron which was used to protect the copper on the bottom of the constance frigate having been subjected to chemical analysis, the following are the results. "this iron, which was in small fragments, very friable, little attracted by the loadstone, soft to the touch, and soiling the fingers like plumbago, gave out in rubbing it a very strong smell, very much like that of burnt linseed oil. its colour on the exterior was a brownish yellow, and its interior a blackish grey, studded with little points extremely brilliant. "a short time after they had been taken from the keel of the frigate, where they were covered with a layer of hydrated peroxide of iron, of six or eight lines in thickness, and been enclosed in a paper box, these fragments became strongly heated, and underwent a real combustion by means of the oxygen of the atmosphere; the combustion was accompanied by the production of a certain quantity of aqueous vapour. "in order to ascertain whether this elevation of temperature was really alone owing to the absorption of the oxygen, a case containing twelve _grammes_ of this iron was placed under a receiver, which contained two hundred millimetres, inverted over a tube of mercury; and it was observed, in the course of an hour, that this air had diminished by forty millimetres, or one-fifth of its volume. examining afterwards that which remained in the receiver, it was discovered that it had no effect whatever either on lime-water or the tincture of _tournesol_,--that it was not inflammable,--that it extinguished a candle; in a word, that it presented all the negative qualities of azotic gas, strongly infected with the smell before stated. "it must be evident that the oxygen which was absorbed in this experiment was employed solely in burning the iron, which was already in a state of _protoxide_, as was indicated by its little degree of cohesion, by the avidity with which it seized this principle, and by its dissolving in sulphuric acid, which operated without effervescence, and without disengaging hydrogen gas. "five _grammes_ of this oxidized iron being reduced to an impalpable powder, and then made red-hot in a platina crucible, and mixed with three parts of _potasse à l'alcool_, were reduced to a clammy mass, coloured on its edges with a clear beautiful green, and with a greenish yellow on the other parts; which at once indicated the presence of a small portion of manganese, and that of a little _chrôme_; metals which are found united in almost all sorts of iron. treated in the usual way, this mass exhibited-- "first, traces, scarcely sensible, of these two metals. "secondly, one _gramme_ of brilliant black powder, soft to the touch, staining paper, insoluble in muriatic acid when applied boiling: it was therefore a true percarburet of iron. "thirdly, three _grammes_ and ten _decigrammes_ of peroxide of iron. "on being subjected to the action of boiling water, five grammes of this pulverized iron gave out three _decigrammes_ of soluble matter, composed, for the greater part, of _hydrochlorate_ of iron, and a trace of hydrochlorate of magnesia, together with a little organic matter, the combination of which with the iron will account for the insufferable smell which it gave out when the iron was heated. this saline solution sensibly reddened the litmus paper: an effect which was owing to the muriatic acid, which, in uniting with oxidized iron, and with most other metallic oxides, never forms combinations which are perfectly neutral, but which are always more or less acid. "it has in vain been attempted to discover in this oxidized iron the presence of silex, of alumina, and of the sulphuric and carbonic acids, either free, or in combination. "it results from this analysis, that the fragments of the protectors, which have been the object of it, are composed, in a hundred parts, of about oxidized iron, of plumbago, or percarburet of iron, of matter soluble in water, hydrochlorate of magnesia, hydrochlorate of iron, hydrochlorate of soda, hydrochlorate of magnesia, and organic matter, and of water; as in fragments pulverised and heated for half an hour at a temperature of °, they lost - th of their weight. "as to the reddish yellow matter, with small protuberances like nipples, which formed a thick layer on the surface of the protectors, it was formed of parts of oxide of iron at the most, and parts of water, besides some atoms of hydrochlorate of iron, hydrochlorate of soda, and hydrochlorate of magnesia." * * * * * had not the health of davy unfortunately declined at the very period when his energies were most required, such is the unbounded confidence which all must feel in his unrivalled powers of vanquishing practical difficulties, and of removing the obstacles which so constantly thwart the applications of theory, that little doubt can be entertained but he would soon have discovered some plan by which the adhesion of marine bodies to the copper sheathing might have been prevented, and his principle of voltaic protection thus rendered available. an experiment indeed, altogether founded upon this same principle, has been already proposed, and will be shortly tried in the british navy, by building a schooner, and fastening its materials together with copper bolts, and afterwards sheathing the bottom with thin plates of iron, which are to be protected by bands of zinc. at the same time, another schooner is to be built, in which the fastenings are to consist entirely of iron bolts and nails, the former to be protected by a zinc ring under each head or clench, and the latter to have a small piece of zinc soldered under its head. this plan of protection was first adopted in america, at the recommendation of dr. revere; and upon its successful issue, that gentleman was lately induced to take out letters patent not only in england, but in all the maritime countries of europe, for the sole right of manufacturing iron sheathing, bolts, and nails, thus protected. as no doubt now exists as to the principle of the protection of iron by zinc, the bolts and nails may be expected to remain free from rust as long as the more oxidable metal lasts; but with regard to the success of the iron sheathing, it is impossible to entertain the same confidence; for what, in this case, is to prevent the adhesion of shell-fish and sea-weed upon its surface? let it be remembered, that it is only when the copper is in the act of solution in sea-water that the sheathing remains clean. in the year , the tender to the flagship at plymouth had her copper on one side of the bottom painted with white lead: in six months, this side was covered with long weeds; while the other side, which had been left bright, and consequently exposed to the solvent action of the salt-water, was found entirely free from all such adhesions. chapter xiv. the failure of the ship protectors a source of great vexation to davy.--his letters to mr. poole.--he becomes unwell.--he publishes his discourses before the royal society.--critical remarks--and quotations.--he goes abroad in search of health.--his letter to mr. poole from ravenna.--he resigns the presidency of the royal society.--mr. gilbert elected _pro tempore_.--davy returns to england, and visits his friend mr. poole.--salmonia, or days of fly-fishing.--an analysis of the work, with various extracts to illustrate its character. the friends of sir humphry davy saw with extreme regret that the failure of his plan for protecting copper sheathing had produced in his mind a degree of disappointment and chagrin wholly inconsistent with the merits of the question; that while he became insensible to the voice of praise, every nerve was jarred by the slightest note of disapprobation. i apprehend, however, that the change of character which many ascribed to the mortification of wounded pride, ought in some measure to be referred to a declining state of bodily power, which had brought with it its usual infirmities of petulance and despondency. the letters i shall here introduce may perhaps be considered as indicating that instinctive desire for quiet and retirement which frequently marks a declining state of health, and they will be followed by others of a less equivocal character. to thomas poole, esq. grosvenor street, nov. , . my dear poole, it is very long since i have heard from you, mr. a----, whom you introduced to me, has sometimes given me news of you, and i have always heard of your health and well-being with pleasure. my immediate motive for writing to you now is somewhat, though not entirely selfish. you know have always admired your neighbourhood, and i have lately seen a place advertised there, called, i think,----, not far from quantock, and combining, as far as advertisement can be trusted, scenery, fishing, shooting, interest for money, &c. if it is not sold, pray give me a little idea of it; i have long been looking out for a purchase,--perhaps this may suit me. after all, it may be sold; if so, no harm is done. i go on labouring for utility, perhaps more than for glory; caring something for the judgment of my contemporaries, but more for that of posterity; and confiding with boldness in the solid judgment of time. i have lately seen some magnificent country in the scandinavian peninsula, where nature, if not a kind, is at least a beautiful mother.--i wonder there have not been more poets in the north. i am, my dear poole, very affectionately your old friend, h. davy. to the same. january , . my dear poole, my proposition to come into somersetshire about the th was founded upon two visits which i had to pay in this county, hants; i am now only about sixty miles from you; and had you been at home, i should have come on to nether stowey. the th is the first meeting of the royal society after the holidays; and though i might do my duty by deputy, yet i feel that this would not be right, and i will not have the honour of the chair without conscientiously taking the labours which its possession entails. i regret therefore that i cannot be with you next week. god bless you. believe me always, my dear poole, your affectionate friend, h. davy. to the same. park street, feb. , . my dear poole, * * * * * i had a letter a few days ago from c----, who writes in good spirits, and who, being within a few miles of london, might, as far as his friends are concerned, be at john a grot's house. he writes with all his ancient power. i had hoped that, as his mind became subdued, and his imagination less vivid, he might have been able to apply himself to persevere, and to give to the world some of those trains of thought, so original, so impressive, and at which we have so often wondered. i am writing this letter at a meeting of the trustees of the british museum, which will account for its want of correction. lest i should be more desultory, i will conclude by subscribing myself, my dear poole, your old and affectionate friend, h. davy. to the same. feb. , . my dear poole, i am very much obliged to you for your two letters, which i received in proper time. i have deferred writing, in the hopes that i might be able to pay you a visit and see the property, but i now find this will be impossible. i have a cold, which has taken a stronger and more inflammable character than usual, which obliges me to lay myself up; and in this weather it would be worse than imprudent to travel. i have seen mr. z----, and can perfectly re-echo your favourable sentiments respecting him. i saw the plan of the estate, and heard every thing he had to say respecting the value, real and imaginary, of the lands. he certainly hopes at this moment for a fancy price, and he is right if he can get it. * * * * * i have less fancy for the place, from finding the trout-stream a brook in summer, where salmon-trout, or salmon, could not be propagated; for one of my favourite ideas in a country residence is varied and multiplied experiments on the increase and propagation of fish. what i should really like would be a place with a couple of hundred acres of productive land, and plenty of moor, a river running through it, and the sea before it; and not farther from london than hampshire--a day's journey. there are such places along the coast, though perhaps in my lifetime they will not be disposed of. i should also like to be within a few miles of you; for it is one of the regrets in the life which i lead, that devotion to the cause of science separates me very much from friends that i shall ever venerate and esteem. god bless you, my dear poole, very affectionately yours, h. davy. to the same. pixton near dulverton, nov. , . my dear poole, i cannot be in your neighbourhood, without doing my best to see you; and it is my intention to come to stowey on sunday. i hope i shall find you at home, and quite well. mr. t----, who is here, gives me a very good account of you, which i trust i shall be personally able to verify. if you are at leisure, i will try to shoot a few woodcocks on monday on the quantock hills; on tuesday i must go east. i have not been well lately. i cannot take the exercise which twenty years ago i went lightly and agreeably through. will you have the kindness to hire a pony for me, that i may ride to your hills? i am sorry i did not know of your journey to ireland and scotland. i was in both those countries at the time you visited them, and should have been delighted to have met you. do not write to me; for, even if you should not be at home, stowey is not more than ten or twelve miles out of my way; but i hope i shall find you. i am, my dear poole, your old and sincere friend, h. davy. the complaints, as to the loss of his strength, which are expressed in the preceding letter, were but too well founded. mr. poole informs me that, during this visit in , it was affecting to observe the efforts he made to continue his field sports. from being unable to walk without fatigue, he was compelled to have a pony to take him to the field, from which he dismounted only on the certainty of immediate sport. on his return to london, his indisposition increased: he complained to me of palpitation of the heart, and of an affection in the trachea, which led him to fear that he might be suffering under the disease of which his father died. the fatigue attendant upon the duties of the anniversary of the royal society (november th) completely exhausted him; and after his re-election as president, he was reluctantly obliged to retire, and to decline attending the usual dinner upon that occasion. in january , sir humphry davy published the discourses which he had delivered before the royal society, at six successive anniversary meetings, on the award of the royal and copley medals. they were published in compliance with a resolution of a meeting of the council, held on the st of december . the practice of delivering an annual oration before the royal society, on the occasion of presenting the medal upon sir godfrey copley's donation, prevailed during the presidency of sir john pringle; it was, however, during a long interval discontinued, and only revived during the latter years of sir joseph banks. the discourse usually commenced with a short tribute of respect to the memory of those distinguished fellows who had died since the preceding anniversary. it then proceeded to announce the choice of the council in its award of the medals, enumerating the objects and merits of the several communications which had been honoured with so distinguished a mark of approbation, and stating the circumstances which had directed the judges in their decision. much has been said and written upon the inutility, and even upon the mischievous tendency of this practice; and great stress has been laid upon the vices inseparably connected, as it is asserted, with the style of composition to which it gives origin. it appears to me, however, that it is only against the meretricious execution, not against the temperate use of such discourses, that this charge can be fairly and consistently sustained; and in the chaste and yet powerful addresses of davy, such an opinion will find its best sanction, and obtain its strongest support. does it follow, because praise, when unduly lavished upon the labours of the scientific dead, may create comparisons and preferences injurious to the living, that we are to stifle the noblest aspirations of our nature, and become as cold and silent as the grave that encloses their remains? does it follow, because an undisciplined ardour may have occasionally exaggerated the merits of our contemporaries, that we are henceforth to withhold from them a just tribute of applause at their discoveries--to forego the advantages which science must derive from a plan so well calculated to awaken the flagging attention, to infuse into stagnant research a renewed spirit of animation, and to encourage the industry of the labourer in the abstract regions of science, with prospects gleaming with sunshine, and luxuriant in the fruitfulness which is to reward him? such was the character, such the effect of davy's discourses. they exhibit a great assemblage of diversified talents, and display the refined views he entertained with respect to the mutual relations which the different sciences maintain with each other; they evince, moreover, a great command of language, and a power to give exact expression to what his mind had conceived. to these six discourses is prefixed his address upon taking the chair of the royal society for the first time; the subject of which is "the present state of that body, and the progress and prospects of science." upon this occasion, he particularly adverts to the light which the different branches of science may reflect upon each other. "in pure mathematics--though their nature, as a work of intellectual combination, framed by the highest efforts of human intelligence, renders them incapable of receiving aids from observations of external phenomena, or the invention of new instruments, yet they are, at this moment, abundant in the promise of new applications; and many of the departments of philosophical enquiry which appeared formerly to bear no relation to quantity, weight, figure, or number, as i shall more particularly mention hereafter, are now brought under the dominion of that sublime science, which is, as it were, the animating principle of all the other sciences." "in the theory of light and vision, the researches of huygens, newton, and wollaston, have been followed by those of malus; and the phenomena of polarization are constantly tending to new discoveries; and it is extremely probable that those beautiful results will lead to a more profound knowledge than has hitherto been obtained, concerning the intimate constitution of bodies, and establish a near connexion between mechanical and chemical philosophy." "the subject of heat, so nearly allied to that of light, has lately afforded a rich harvest of discovery; yet it is fertile in unexplored phenomena. the question of the materiality of heat will probably be solved at the same time as that of the undulating hypothesis of light, if, indeed, the human mind should ever be capable of understanding the causes of these mysterious phenomena. the applications of the doctrine of heat to the atomic or corpuscular philosophy of chemistry abound in new views, and probably at no very distant period these views will assume a precise mathematical form." "in electricity, the wonderful instrument of volta has done more for the obscure parts of physics and chemistry, than the microscope ever effected for natural history, or even the telescope for astronomy. after presenting to us the most extraordinary and unexpected results in chemical analysis, it is now throwing a new light upon magnetism. 'suppeditatque novo confestim lumine lumen.' "i must congratulate the society on the rapid progress made in the theory of definite proportions, since it was advanced in a distinct form by the ingenuity of mr. dalton. i congratulate the society on the promise it affords of solving the recondite changes, owing to motions of the particles of matter, by laws depending upon their weight, number, and figure, and which will be probably found as simple in their origin, and as harmonious in their relations, as those which direct the motions of the heavenly bodies, and produce the beauty and order of the celestial systems. "the crystallizations, or regular forms of inorganic matter, are intimately connected with definite proportions, and depend upon the nature of the combinations of the elementary particles; and both the laws of electrical polarity, and the polarization of light, seem related to these phenomena. as to the origin of the primary arrangement of the crystalline matter of the globe, various hypotheses have been applied, and the question is still agitated, and is perhaps above the present state of our knowledge; but there are two principal facts which present analogies on the subject,--one, that the form of the earth is that which would result, supposing it to have been originally fluid; and the other, that in lavas, masses decidedly of igneous origin, crystalline substances, similar to those belonging to the primary rocks, are found in abundance." it is the privilege of genius to be in advance of the age, and to see, "as by refraction, the light, as yet below the horizon." it is with such a feeling that i have introduced the foregoing extracts, which i cannot but regard as prophetic of future discoveries. the first discourse was delivered on the th of november , on the occasion of announcing the award of two medals, on sir godfrey copley's donation; one to j. f. w. herschel, esq. for his various papers on mathematical and physico-mathematical subjects; and the other, to captain edward sabine, r.a., for his papers containing an account of his various experiments and observations made during a voyage and expedition in the arctic regions. as i am desirous that the reader should be made acquainted with the nature and style of the address with which he accompanied the presentation of the medal, i cannot select a happier example, or one in the sentiments of which every person will more readily participate, than the following:-- "mr. herschel--receive this medal, sir, as a mark of our respect, and of our admiration of those talents which you have applied with so much zeal and success, and preserve it as a pledge of future exertions in the cause of science and of the royal society; and, believe me, you can communicate your labours to no public body by whom they will be better received, or through whose records they will be better known to the philosophical world. you are in the prime of life, in the beginning of your career, and you have powers and acquirements capable of illustrating and extending every branch of physical enquiry; and, in the field of science, how many are the spots not yet cultivated! where the laws of sensible become connected with those of insensible motions, the mechanical with the chemical phenomena, how little is known! in electricity, magnetism, in the relations of crystallized forms to the weight of the elements of bodies, what a number of curious and important objects of research! and they are objects which you are peculiarly qualified to pursue and illustrate. "may you continue to devote yourself to philosophical pursuits, and to exalt your reputation, already so high-- 'virtutem extendere factis.' and these pursuits you will find not only glorious, but dignified, useful, and gratifying in every period of life: this, indeed, you must know best in the example of your illustrious father, who, full of years and of honours, must view your exertions with infinite pleasure; and who, in the hopes that his own imperishable name will be permanently connected with yours in the annals of philosophy, must look forward to a double immortality." in the discourse of the succeeding year, it was his painful duty to announce the death of the elder herschel, whom, in his former address, he had eulogized in such eloquent and touching language. in alluding to the labours and discoveries of sir william herschel, he observed, that "they have so much contributed to the progress of modern astronomy, that his name will probably live as long as the inhabitants of this earth are permitted to view the solar system, or to understand the laws of its motions. the world of science--the civilized world, are alike indebted to him who enlarges the boundaries of human knowledge, who increases the scope of intellectual enjoyment, and exhibits the human mind in possession of new and unknown powers, by which it gains, as it were, new dominions in space; acquisitions which are imperishable--not like the boundaries of terrestrial states and kingdoms, or even the great monuments of art, which, however extensive and splendid, must decay--but secured by the grandest forms and objects of nature, and registered amongst her laws." one more quotation, and i shall conclude with the conviction that the splendid specimens i have adduced must fully justify the opinion already offered as to the taste, power, and eloquence with which, as president of the royal society, he discharged the most delicate and arduous of all its duties. in his address to mr. (now dr.) buckland, on delivering to him the medal for his important memoir on the fossile remains discovered in the cave near kirkdale, he thus concludes:--"if we look with wonder upon the great remains of human works, such as the columns of palmyra, broken in the midst of the desert; the temples of pæstum, beautiful in the decay of twenty centuries; or the mutilated fragments of greek sculpture in the acropolis of athens, or in our own museum, as proofs of the genius of artists, and power and riches of nations now past away; with how much deeper a feeling of admiration must we consider those grand monuments of nature which mark the revolutions of the globe--continents broken into islands; one land produced, another destroyed; the bottom of the ocean become a fertile soil; whole races of animals extinct, and the bones and exuviæ of one class covered with the remains of another; and upon these graves of past generations--the marble or rocky tombs, as it were, of a former animated world, new generations rising, and order and harmony established, and a system of life and beauty produced, as it were, out of chaos and death, proving the infinite power, wisdom, and goodness of the great cause of all being!" * * * * * i have noticed the apparent commencement of that general indisposition which had for some time been stealing upon him, undermining his powers, oppressing his spirits, and subduing his best energies; but in the end of , his complaint assumed a more decided and alarming form. feeling more than usually unwell, while on a visit to his friend lord gage, he determined to return to london, and was seized while on his journey, at mayersfield, with an apoplectic attack. prompt and copious bleeding, however, on the spot, arrested the symptoms more immediately threatening the extinction of life, and enabled him to reach home; but paralysis, the usual consequence of such seizures, had obviously, though at first but slightly, diminished his muscular powers, and given an awkwardness to his gait. as soon as the more immediate danger of the attack had passed away, it was thought expedient to recommend, as the best means of his farther recovery, a residence in the southern part of europe, where he would be removed from all the cares and anxieties that were inseparably connected with his continuance in london; and he accordingly quitted england, with the intention of spending what remained of the winter in italy. the following interesting letter to his friend will sufficiently explain the serious character of his malady, and the degree of bodily infirmity which accompanied it. to thomas poole, esq. ravenna, march , . my dear poole, i should have answered your letter immediately, had it been possible; but i was, at the time i received it, very ill, in the crisis of the complaint under which i have long suffered, and which turned out to be a determination of the blood to the brain; at last producing the most alarming nervous symptoms, and threatening the loss of power and of life. had i been in england, i should gladly have promoted the election of your friend at the athenæum: your certificate of character would always be enough for me; for, like our angling evangelical isaac walton, i know you choose for your friends only good men. i am, thank god, better, but still very weak, and wholly unfit for any kind of business and study. i have, however, considerably recovered the use of all the limbs that were affected; and as my amendment has been slow and gradual, i hope in time it may be complete: but i am leading the life of an anchorite, obliged to abstain from flesh, wine, business, study, experiments, and all things that i love; but this discipline is salutary, and for the sake of being able to do something more for science, and, i hope, for humanity, i submit to it; believing that the great source of intellectual being so wills it for good. i am here lodged in the apostolical palace, by the kindness of the vice-legate of ravenna, a most admirable and enlightened prelate, and who has done every thing for me that he could have done for a brother. i have chosen this spot of the declining empire of rome, as one of solitude and repose, as out of the way of travellers, and in a good climate; and its monuments and recollections are not without interest. here dante composed his divine works. here byron wrote some of his best and most moral (if such a name can be applied) poems; and here the roman power that began among the mountains with romulus, and migrated to the sea, bounding asia and europe under constantine, made its last stand, in the marshes formed by the eridanus, under theodorick, whose tomb is amongst the wonders of the place. after a month's travel in the most severe weather i ever experienced, i arrived here on the th of february. the weather has since been fine. my brother and friend, who is likewise my physician, accompanied me; but he is so satisfied with my improvement, as to be able to leave me for corfu; but he is within a week's call. i have no society here, except that of the amiable vice-legate, who is the governor of the province; but this is enough for me, for as yet i can bear but little conversation. i ride in the pine forest, which is the most magnificent in europe, and which i wish you could see. you know the trees by claude lorraine's landscapes: imagine a circle of twenty miles of these great fan-shaped pines, green sunny lawns, and little knolls of underwood, with large junipers of the adriatic in front, and the apennines still covered with snow behind. the pine wood partly covers the spot where the roman fleet once rode,--such is the change of time! it is my intention to stay here till the beginning of april, and then to go to the alps, for i must avoid the extremes of heat and cold. god bless you, my dear poole. i am always your old and sincere friend, h. davy. feeling that his recovery was tardy, and that perfect mental repose was more than ever necessary for its advancement, he determined to resign the chair of the royal society; and he accordingly announced that intention, by a letter to his friend mr. davies gilbert, vice-president of the society. to davies gilbert, esq. m.p. v.p.r.s. &c. &c. salzburgh, july , . my dear sir, yesterday, on my arrival here, i found your two letters. i am sorry i did not receive the one you were so good as to address to me at ravenna; nor can i account for its miscarriage. i commissioned a friend there to transmit to me my letters from that place after my departure, and i received several, even so late as the middle of may, at laybach, which had been sent to italy, and afterwards to illyria. i did not write to you again, because i always entertained hopes of being able to give a better account of the state of my health. i am sorry to say the expectations of my physicians of a complete and rapid recovery have not been realized. i have gained ground, under the most favourable circumstances, very slowly; and though i have had no new attack, and have regained, to a certain extent, the use of my limbs, yet the tendency of the system to accumulate blood in the head still continues, and i am obliged to counteract it by a most rigid vegetable diet, and by frequent bleedings with leeches and blisterings, which of course keep me very low. from my youth up to last year, i had suffered, more or less, from a slight hemorrhoidal affection; and the fulness of the vessels, then only a slight inconvenience, becomes a serious and dangerous evil in the head, to which it seems to have been transferred. i am far from despairing of an ultimate recovery, but it must be a work of time, and the vessels which have been over distended only very slowly regain their former dimensions and tone: and for my recovery, not only diet and regimen and physical discipline, but a freedom from anxiety, and from all business and all intellectual exertion, is absolutely required. under these circumstances, i feel it would be highly imprudent and perhaps fatal for me, to return, and to attempt to perform the official duties of president of the royal society. and as i had no other feeling for that high and honourable situation, except the hope of being useful to society, so i would not keep it a moment without the security of being able to devote myself to the labour and attention it demands. i beg therefore you will be so good as to communicate my resignation to the council and to the society at their first meeting in november, after the long vacation; stating the circumstances of my severe and long continued illness, as the cause. at the same time, i beg you will express to them how truly grateful i feel for the high honour they have done me in placing me in the chair for so many successive years. assure them that i shall always take the same interest in the progress of the grand objects of the society, and throughout the whole of my life endeavour to contribute to their advancement, and to the prosperity of the body. should circumstances prevent me from sending, or you from receiving any other communication from me before the autumn (for nothing is more uncertain than the post in austria, as they take time to read the letters), i hope this, which i shall go to bavaria to send, will reach you safe, and will be sufficient to settle the affair of resignation. it was my intention to have said nothing on the subject of my successor. i will support by all the means in my power the person that the leading members of the society shall place in the chair; but i cannot resist an expression of satisfaction in the hope you held out, that an illustrious friend of the society, illustrious from his talents, his former situation, and, i may say, his late conduct, is likely to be my successor. i wish my name to be in the next council, as i shall certainly return, _deo volente_, before the end of the session, and i may, i think, be of use; and likewise, because i hope it may be clearly understood that my feelings for the society are, as they always were, those of warm attachment and respect. writing still makes my head ache, and raises my pulse. i will therefore conclude, my dear sir, in returning you my sincere thanks for the trouble you have had on my account, and assuring you that i am your obliged and grateful friend and servant, h. davy. pray acknowledge the receipt of this letter, by addressing me, "_poste restante_, laybach, illyria, austria;" and let me know if mr. hudson is still assistant-secretary, and where mr. south is. i send this letter from frauenstein, bavaria, july , that it may not be opened, as all my letters were at salzburgh. there was one of them must have _amused_ prince metternich, on the state of parties in england, from a member of the upper house. in consequence of this letter, the council of the royal society, by a resolution passed at a very full meeting held on the th of november, , appointed mr. davies gilbert to fill the chair, until the general body should elect a president, at the ensuing anniversary. the following letter will show his subsequent course of proceeding. to thomas poole, park street, grosvenor square, oct. , . my dear poole, i hope you received a letter which i addressed to you from ravenna in the spring. it was my intention to have returned to italy from the alpine countries, where i spent the summer; but my recovery has been so slow, and so much uneasiness in the head and weakness in the limbs remained in september, that i thought it wiser to return to my medical advisers in london. i have consulted all the celebrated men who have written upon or studied the nervous system. they all have a good opinion of my case, and they all order absolute repose for at least twelve months longer, and will not allow me to resume my scientific duties or labours at present; and they insist upon my leaving london for the next three or four months, and advise a residence in the west of england. now, my dear friend, you recollect our conversation upon the subject of a residence--i think mr. c.'s is not very far from you. pray let me know something on this head. i want very little of any thing, for i am almost on a vegetable diet; and a little horse exercise, a very little shooting, and a little quiet society, are what i am in search of, with some facilities of procuring books. i have thought of minehead, ilfracombe, lymouth, and penzance; but i have not yet determined the point. horse exercise and shooting are necessary to bring back my limbs to their former state, and therefore bath and brighton will not do for me. god bless you, my dear poole, and pray let me hear from you. your affectionate, h. davy. p.s. i hope you got the copy of my discourses. to the same. firle, near lewes, nov. , . my dear poole, i have this moment received your very kind and most friendly letter. i have made my first visit to my friend lord g----, where i was taken ill last year; and have borne the journey well, and have enjoyed the small society here; but i am very weak indeed, and i cannot yet walk more than a mile. one of three plans, i shall hope to adopt; two of them you have most amiably suggested, the other is to go to penzance. my only objection to the last is the fear of too much society. whatever i do, i will first come to you and take your advice. when i returned, i had little hopes of recovery; but the assurances of my physicians that i may again, with care, be re-established, have revived me, and i have certainly gained ground, and gained strength, by the plan i am now pursuing. as soon as i return to london, i will write to you. if i can find a companion, i think mr. c----'s house will do admirably; but i must see it, as a temperate situation is a _sine quâ non_. i need not say how grateful i am for your kindness, and if i recover, how delighted i shall be to owe the means to so excellent and invaluable a friend. god bless you. i am, my dear poole, your affectionate, h. davy. to the same. firle, nov. . my dear poole, i am going to london to-morrow, and after staying two or three days, to try a new plan of medical treatment, which my physicians recommend, i shall come westward, and profit by your kindness, and adopt whichever of the plans will promise to be most salutary. if i take mr. c----'s house, lady davy will come to me. with respect to society, i want only a friend, or one person or two at most, to prevent entire solitude, and i am too weak to bear much conversation, and wholly unfit to receive any but persons with whom i am in the habits of intimacy. i can hardly express to you how deeply i feel your kindness. * * * * * as i must travel slowly, i shall not probably be at stowey before wednesday or thursday next. pray do not ask any body to meet me. i am upon the _strictest_ diet,--a wing of a chicken and a plain rice or bread pudding is the extreme of my _gourmanderie_. god bless you. my dear poole, your affectionate friend, h. davy. mr. poole has been so obliging as to communicate to me some interesting particulars connected with the visit to which the foregoing letters allude. "during this last visit, (november and december ,) his bodily infirmity was very great, and his sensibility was painfully alive on every occasion. unhappily, he had to sustain the affliction of the sudden death of mr. r----, the son of a friend whom he highly valued; and though this afflicting event was, by the considerate and anxious attention of lady davy, first communicated to me by letter, to be imparted to him with every precaution, to avoid his being suddenly shocked, yet it was many days before he could recover his usual spirits, feeble as they were, and resume his wonted occupation. "on his arrival, he said, 'here i am, the ruin of what i was;' but nevertheless, the same activity and ardour of mind continued, though directed to different objects. he employed himself two or three hours in the morning on his _salmonia_, which he was then writing; he would afterwards take a short walk, which he accomplished with difficulty, or ride. after dinner, i used to read to him some amusing book. we were particularly interested by southey's life of nelson. 'it would give southey,' he said, 'great pleasure, if he knew how much his narrative affected us.'[ ] [ ] his admiration of this work bursts forth in his _salmonia_, which he was writing at that time. he styles it "an immortal monument raised by genius to valour." "in the evening, mr. and mrs. w----, the former of whom he had long known, frequently came to make a rubber at whist. he was averse to seeing strangers; but on being shown the drawings of natural history of a friend of mine of great talent, mr. baker of bridgwater, he was anxious to know him, and was much pleased with his company. he suggested to him various subjects for investigation, concerning insects, and fish, particularly the eel. what pleasure would it give him were he now alive, to learn the interesting result of those suggestions! i hope the public will soon be made acquainted with them. "natural history in general had been a favourite subject with him throughout his protracted illness; and during this last visit to me, he paid attention to that only; 'for,' said he, 'i am prohibited applying, and indeed i am incapable of applying, to any thing which requires severe attention.' "during the same visit, i remember his inherent love of the laboratory, if i may so express myself, being manifested in a manner which much interested me at the moment. on his visiting with me a gentleman in this neighbourhood, who had offered him his house, and who has an extensive philosophical apparatus, particularly complete in electricity and chemistry, he was fatigued with the journey, and as we were walking round the house very languidly, a door opened, and we were in the laboratory. he threw a glance around the room, his eyes brightened in the action, a glow came over his countenance, and he looked like himself, as he was accustomed to appear twenty years ago. "you are aware that he was latterly a good shot, always an expert angler, and a great admirer of old isaac walton; and that he highly prided himself upon these accomplishments. i used to laugh at him, which he did not like; but it amused me to see such a man give so much importance to those qualifications. he would say, 'it is not the sport only, though there is great pleasure in successful dexterity,[ ] but it is the ardour of pursuit, pure air, the contemplation of a fine country, and the exercise--all tend to invigorate the body, and to excite the mind to its best efforts.' [ ] mr. children has just communicated to me the following amusing anecdote, which may be adduced in illustration of the delight he took in that sporting dexterity to which he alludes in the above passage. davy, with a party of friends, had been engaged for several hours in fishing for pike, but very unsuccessfully; our philosopher gave up the sport in despair, but his companions having determined to try some more propitious spots, left him to his contemplations. about an hour afterwards, mr. children, on returning to his friend, saw him at a distance seated upon a gate, and apparently lashing the air with his fishing-line. what could be his object? as soon as mr. children came sufficiently near to make a signal, davy, by his gestures, earnestly entreated him to keep away, while he continued his mysterious motions. at length, however, mr. children's patience was exhausted, and he walked up to him. "was ever any thing more provoking!" exclaimed davy; "if you had only remained quiet another minute i should have caught him--it is most vexatious!" "caught what?" asked mr. children. "a dragon-fly," (_libellula_,) answered davy. "during your absence i have been greatly amused by watching the feeding habits of that insect, and having observed the eagerness with which they snapped up the little '_midges_,' i determined to arm my hook with one, and i can assure you i have had no small degree of sport; and had it not been for your unwelcome intrusion, i should most undoubtedly have captured one of them." "these amusements seemed to become more and more important in his estimation, as his health declined. it was affecting to observe the efforts he made to continue them with diminished strength. from being unable to walk without fatigue for many hours, he was, when he came to me in november , obliged to have a pony to carry him to the field, from which he dismounted only on the certainty of immediate sport. in the following year, he could only take short and occasional rides to the covers, with his dogs around him, and his servant walking by his side and carrying his gun, but which i believe he never fired. "during this visit, he more than once observed, 'i do not wish to live, as far as i am personally concerned; but i have views which i could develope, if it pleased god to save my life, which would be useful to science and to mankind.'" davy returned to town in december, and after an interval wrote the following letter: to thomas poole, esq. park street, grosvenor square, dec. , . my very dear friend, i know no reason why i have not written to you. it has been my intention every day, and i have been every day prevented by the sense of want of power, which is so painful a symptom of my malady. i continue much as i was. my physicians augur well, and i have some repose in the hopes connected with the indefinite future. in the last twelve-month, which i hope is a large portion, on the whole, of my purgatory expiation for crimes of commission or omission, the most cheerful, or rather the least miserable, days that i spent, were a good deal owing to your kindness, which i shall never forget. i would, if it were possible, make my letter something more than a mere bulletin of health, or the expression of the feelings of a sick man; but i can communicate no news. the papers will tell you more than is true; and our politicians seem ignorant of what they are to do at home, much more abroad. * * * * * i have got for you a copy of my lectures on the chemistry of agriculture, which i shall send to you by the first opportunity. god bless you, my dear poole. i am always your sincere, grateful, and affectionate friend, h. davy. in the letter which follows, davy dwells upon a subject in natural history, which appears to have greatly occupied his thoughts, and to have continued a predominant subject of his contemplation, even to the latest day of his life. to thomas poole, esq. park street, january , . my dear friend, i write to you immediately, because that part of your letter which relates to mr. baker's pursuits interests me very much: but before i begin on this subject, i will give you a short bulletin of the state of my health. i go on much as i did at stowey, and my physicians have made no alterations in the plan of treatment: i am not worse, and they tell me i shall be better. now for mr. baker--i am very glad that he is occupied with those enquiries. i am particularly anxious for information on the generation of eels; it is an unsolved problem since the time of aristotle. i am sure that all eels come from the sea, where they are bred; but there may be one or two species or varieties of them. what mr. baker says about the difference between the common eel and the conger is well worthy of attention; but i have known changes more extraordinary than the obliteration, or destruction, of a small tubular member occasioned by difference of habits. were the salt-water eels and the fresh-water eels which he examined of the same size? many individuals of various sizes should be examined to establish the fact of their specific difference. this would be the season for examining the genital organs of eels, for they breed in winter; and were i a little better, i should go to the sea for the purpose of making enquiries on the subject. sir everard home is firmly convinced that the animal is hermaphrodite and impregnates itself: this, though possible, appears to me very strange in so large an animal. if mr. baker will determine this point, i can promise him an immortality amongst our philosophical anglers and natural historians; and if he will give us the history of water-flies, imitated by fly-fishers, he will command our immediate gratitude. pray communicate this letter to him with my best wishes, and with my hopes that his talents, which are very great, will be applied to enlighten us. i can give you no news; the weather is dreadful, and the blacks and yellows are descending in fog. i long for the fresh air of your mountains. god bless you, my dear poole. many--many happy new years to you. pray remember me, with the compliments of this day, to your excellent neighbours at stowey. your affectionate friend, h. davy. to the same. my dear poole, park street, march . your letter has given me great pleasure; first, because you, who are an enlightened judge in such matters, approve of my humble contribution to agriculture; and, secondly, because it makes me acquainted with your kind feelings, health, and mr. baker's interesting pursuits. mr. baker appears to me to have distinctly established the point that the eel and conger are of different species; and from his zeal and activity, i hope the curious problem of the generation of these animals will be solved. i shall expect with impatience the results of his enquiries. now for my health, my very dear friend. i wish i could speak more favourably; i certainly do not lose ground, but i am doubtful if i gain any; but i do not despair. i am going, by the advice of my physicians, to try another continental journey. if i get considerably better, i shall winter in italy, where, in this case, i shall hope to see you, and where i shall have an apartment ready for you in rome. i have not been idle since i left your comfortable and hospitable house. i have finished my _salmonia_, and sent it to the press.--"_flumina amo sylvasque inglorius._"--i do not think you will be displeased with this little _jeu_ of my sick hours. mr. a---- was very amiable in calling on me. there is nothing that annoys me so much in my illness as my helplessness in not being able to indulge in society. your grateful and affectionate friend, h. davy. we will now, for a while, leave our philosopher to pursue his journey to italy, while we take a review of his salmonia; the first edition of which was published in the spring of . the second, and much improved edition,[ ] from which i shall take my extracts, is dated from laybach, illyria, september , , but which did not appear until . [ ] "salmonia, or days of fly-fishing; in a series of conversations; with some account of the habits of fishes belonging to the genus salmo. by an angler. second edition.--london, john murray, ." we are told in the preface, that these pages formed the occupation of the author during some months of severe and dangerous illness, when he was wholly incapable of attending to more useful studies, or of following more serious pursuits;--that they constituted his amusement in many hours, which otherwise would have been unoccupied and tedious;--and that they are published in the hope that they may possess an interest for those persons who derive pleasure from the simplest and most attainable kind of rural sports, and who practise the art, or patronise the objects of contemplation, of the philosophical angler. he informs us that the conversational manner and discursive style were chosen as best suited to the state of health of the author, who was incapable of considerable efforts and long continued attention; and he adds, that he could not but have in mind a model, which has fully proved the utility and popularity of this method of treating this subject--"the complete angler," by walton and cotton. the characters chosen to support these conversations, were halieus, who is supposed to be an accomplished fly-fisher--ornither, who is to be regarded as a gentleman generally fond of the sports of the field, though not a finished master of the art of angling--poietes, who is to be considered as an enthusiastic lover of nature, and partially acquainted with the mysteries of fly-fishing; and physicus, who is described uninitiated as an angler, but as a person fond of enquiries in natural history and philosophy. such are the personages by whose aid the machinery is to be worked; but he tells us that they are of course imaginary, though the sentiments attributed to them, the author may sometimes have gained from recollections of real conversations with friends, from whose society much of the happiness of his early life had been derived; and he admits that, in the portrait of the character of halieus, given in the last dialogue, a likeness will not fail to be recognised to that of the character of a most estimable physician, ardently beloved by his friends, and esteemed and venerated by the public. the work is dedicated to dr. babington, "in remembrance of some delightful days passed in his society, and in gratitude for an uninterrupted friendship of a quarter of a century." i am informed by lady davy, that the engravings of the fish, by which the work is illustrated, are from drawings of his own execution; so that he could not, like old isaac walton, "take the liberty to commend the excellent pictures to him that likes not the book, because they concern not himself." it has frequently happened that, while works of deep importance have justly conferred celebrity upon the author, his minor productions have been entirely indebted to his name for their popularity, and to his authority for their value. this, however, cannot be said of salmonia, for it possesses the stamp of original genius, and bears internal evidence of a talent flowing down from a very high source of intelligence. in a scientific point of view, it exhibits that penetrating observation by which a gifted mind is enabled to extract out of the most ordinary facts and every-day incidents, novel views and hidden truths; while it shows that a humble art (i beg pardon of the brothers of the angle) may, through the skill of the master, be made the means of calling forth the affections of the heart, and of reflecting all the colours of the fancy. by regarding the work in relation to the history and condition of its author, it certainly acquires much additional interest. the familiar and inviting style of the dialogue, whenever he discusses questions of natural history, must convince us that he was as well calculated to instruct in the lyceum, as we long since knew him to be to teach in the academy. composed in the hour of sickness and prostration, the work displays throughout its composition a tone of dignified morality and an expansion of feeling, which may be regarded as in unison with a mind chastened but not subdued, and looking forward to a better state of existence. "i envy," says he, "no quality of the mind or intellect in others; be it genius, power, wit, or fancy: but if i could choose what would be most delightful, and i believe most useful to me, i should prefer a firm religious belief to every other blessing; for it makes life a discipline of goodness; creates new hopes, when all earthly hopes vanish; and throws over the decay, the destruction of existence, the most gorgeous of all lights; awakens life even in death, and from corruption and decay calls up beauty and divinity; makes an instrument of torture and of shame the ladder of ascent to paradise; and, far above all combinations of earthly hopes, calls up the most delightful visions of palms and amaranths, the gardens of the blest, the security of everlasting joys, where the sensualist and the sceptic view only gloom, decay, annihilation, and despair!" while describing an animated scene of insect enjoyment, he bursts into an apostrophe, highly characteristic of that quick and happy talent for seizing analogies, which so eminently distinguished all his writings. i shall quote the passage. "_physicus._--since the sun has disappeared, the cool of the evening has, i suppose, driven the little winged plunderers to their homes; but see, there are two or three humble bees which seem languid with the cold, and yet they have their tongues still in the fountain of honey. i believe one of them is actually dead, yet his mouth is still attached to the flower. he has fallen asleep, and probably died whilst making his last meal of ambrosia. "_ornither._--what an enviable destiny, quitting life in the moment of enjoyment, following an instinct, the gratification of which has been always pleasurable! so beneficent are the laws of divine wisdom. "_physicus._--like ornither, i consider the destiny of this insect as desirable, and i cannot help regarding the end of human life as most happy, when terminated under the impulse of some strong energetic feeling, similar in its nature to an instinct. i should not wish to die like attila, in a moment of gross sensual enjoyment; but the death of epaminondas or nelson, in the arms of victory, their whole attention absorbed in the love of glory, and of their country, i think really enviable. "_poietes._--i consider the death of the martyr or the saint as far more enviable; for, in this case, what may be considered as a divine instinct of our nature is called into exertion, and pain is subdued, or destroyed, by a secure faith in the power and mercy of the divinity. in such cases, man rises above mortality, and shows his true intellectual superiority. by intellectual superiority, i mean that of his spiritual nature, for i do not consider the results of reason as capable of being compared with those of faith. reason is often a dead weight in life, destroying feeling, and substituting, for principle, calculation and caution; and, in the hour of death, it often produces fear or despondency, and is rather a bitter draught than nectar or ambrosia in the last meal of life. "_halieus._--i agree with poietes. the higher and more intense the feeling under which death takes place, the happier it may be esteemed; and i think even physicus will be of our opinion, when i recollect the conclusion of a conversation in scotland. the immortal being never can quit life with so much pleasure as with the feeling of immortality secure, and the vision of celestial glory filling the mind, affected by no other passion than the pure and intense love of god." we are not to suppose that, however soothing and consolatory such feelings and hopes may have been, they weaned him from the world, or diminished his natural love of life; on the contrary, no one would have more gratefully received the services of a medea, as the following passage will sufficiently testify. "ah! could i recover any thing like that freshness of mind which i possessed at twenty-five, and which, like the dew of the dawning morning, covered all objects and nourished all things that grew, and in which they were more beautiful even than in midday sunshine,--what would i not give! all that i have gained in an active and not unprofitable life. how well i remember that delightful season, when, full of power, i sought for power in others; and power was sympathy, and sympathy power;--when the dead and the unknown, the great of other ages and of distant places were made, by the force of the imagination, my companions and friends;--when every voice seemed one of praise and love;--when every flower had the bloom and odour of the rose; and every spray or plant seemed either the poet's laurel, or the civic oak--which appeared to offer themselves as wreaths to adorn my throbbing brow. but, alas! this cannot be.----" after the example of the great patriarch of anglers, the author of salmonia commences, through the assistance of the principal interlocutor of the dialogue, halieus, to enumerate the delights of his art, and to vindicate it from the charge of cruelty. "_halieus._--the search after food is an instinct belonging to our nature; and from the savage in his rudest and most primitive state, who destroys a piece of game, or a fish, with a club or spear, to man in the most cultivated state of society, who employs artifice, machinery, and the resources of various other animals, to secure his object, the origin of the pleasure is similar, and its object the same: but that kind of it requiring most art may be said to characterize man in his highest or intellectual state; and the fisher for salmon and trout with the fly employs not only machinery to assist his physical powers, but applies sagacity to conquer difficulties; and the pleasure derived from ingenious resources and devices, as well as from active pursuit, belongs to this amusement. then, as to its philosophical tendency, it is a pursuit of moral discipline, requiring patience, forbearance, and command of temper. as connected with natural science, it may be vaunted as demanding a knowledge of the habits of a considerable tribe of created beings,--fishes, and the animals that they prey upon, and an acquaintance with the signs and tokens of the weather, and its changes, the nature of waters, and of the atmosphere. as to its poetical relations, it carries us into the most wild and beautiful scenery of nature; amongst the mountain lakes, and the clear and lovely streams that gush from the higher ranges of elevated hills, or that make their way through the cavities of calcareous strata. how delightful in the early spring, after the dull and tedious time of winter, when the frosts disappear and the sunshine warms the earth and waters, to wander forth by some clear stream, to see the leaf bursting from the purple bud, to scent the odours of the bank perfumed by the violet, and enamelled, as it were, with the primrose and the daisy; to wander upon the fresh turf below the shade of trees, whose bright blossoms are filled with the music of the bee; and on the surface of the waters to view the gaudy flies sparkling like animated gems in the sunbeams, whilst the bright and beautiful trout is watching them from below; to hear the twittering of the water birds, who, alarmed at your approach, rapidly hide themselves beneath the flowers and leaves of the water-lily; and, as the season advances, to find all these objects changed for others of the same kind, but better and brighter, till the swallow and the trout contend, as it were, for the gaudy mayfly, and till, in pursuing your amusement in the calm and balmy evening, you are serenaded by the songs of the cheerful thrush and melodious nightingale, performing the offices of paternal love, in thickets ornamented with the rose and woodbine." on vindicating the pursuit from the charge of cruelty, he has advanced an argument that has not been commonly adduced upon this occasion. we have indeed all heard, that the operation of skinning is a matter of indifference to eels when they are used to it; but we are now told fish are so little annoyed by the hook, that though a trout has been hooked and played with for some minutes, he will often, after his escape with the artificial fly in his mouth, take the natural fly, and feed as if nothing had happened; having apparently learnt only from the experiment, that the artificial fly is not proper food. "i have caught pikes with four or five hooks in their mouths, and tackle which they had broken only a few minutes before; and the hooks seemed to have had no other effect than that of serving as a sort of _sauce piquante_, urging them to seize another morsel of the same kind." our author, however, takes a more special defence, by observing that, unlike old isaac, he employs an artificial fly, instead of a living bait. our notions about the cruelty of field sports is extremely capricious. until the time of the reformation, the canon law prohibited the use of the sanguinary recreations of hunting, hawking, and fowling, while the clergy, on account of their leisure, were allowed to exercise the harmless and humane art of angling. in later days, the indignation against this art has been excited by the supposed sufferings of the worm or bait, rather than by those of the fish; and thus far the author of salmonia assumed a strong posture of defence; but he did not avail himself of all the advantages it commanded. he might have pleaded, that every fish he caught by his artificial fly was destined to prey upon an insect, and that by substituting a piece of silk for the latter, he would for every fish he might destroy, save from destruction many of those fairy beings that animate the air and sparkle in the sunbeam;--but it is, after all, folly to argue upon the subject of cruelty in our field sports. that animals should live by preying upon each other is the very basis of the scheme of creation; and in these days it is not necessary to expose the absurdities of the system of samos and indostan. dr. franklin, at one period of his life, entertained a sentimental abhorrence at eating any thing that had possessed life; and the reader may, perhaps, not object to be reminded of the manner in which he was cured of his prejudice. "i considered," says he, "the capture of every fish as a sort of murder, committed without provocation, since these animals had neither done, nor were capable of doing, the smallest injury to any one that should justify the measure. this mode of reasoning i conceived to be unanswerable. meanwhile, i had formerly been extremely fond of fish; and when one of the cod was taken out of the frying-pan, i thought its flavour delicious. i hesitated some time between principle and inclination, till at last recollecting that, when the cod had been opened, some small fish were found in its belly, i said to myself, 'if you eat each other, i see no reason why we may not eat you,'--(his "wish was father to that thought")--i accordingly dined on the cod with no small degree of pleasure, and have since continued to eat like the rest of mankind." halieus is made to admit the danger of analysing too closely the moral character of any of our field sports; and yet, in the concluding chapter, he very unfairly and inconsistently attempts to ridicule the pursuit of a fox-hunter, "risking his neck to see the hounds destroy an animal which he preserves to be destroyed, and which is good for nothing." he who pursues a pleasure because it is rational, reasons because he cannot feel. "when the heart," says sterne, "flies out before the understanding, it saves the judgment a world of pains." having, as the author thinks satisfactorily, settled the preliminary questions, halieus, succeeds in persuading physicus to join him in fishing excursions; just as _piscator_ is represented by old isaac, as having enlisted _venator_ into the brotherhood of the angle. the dialogue now proceeds with great animation, during which the art and mystery of piscatory tactics are unfolded with great skill; for the details of which the reader must be referred to the work itself. if, however, he be not already an angler, it may save him a world of pains to be informed, that to learn to fish by the book is little less absurd than "to make hay by the fair days in the almanack." the manner in which he treats the various subjects of natural history necessarily connected with the pursuit is both amusing and instructive; and the whole work is studded and gemmed, as it were, with the most poetical descriptions. in speaking of the swallow, _poietes_ exclaims--"i delight in this living landscape! the swallow is one of my favourite birds, and a rival of the nightingale; for he cheers my sense of seeing as much as the other does my sense of hearing. he is the glad prophet of the year, the harbinger of the best season: he lives a life of enjoyment amongst the loveliest forms of nature: winter is unknown to him; and he leaves the green meadows of england in autumn, for the myrtle and orange groves of italy, and for the palms of africa: he has always objects of pursuit, and his success is secure. even the beings selected for his prey are poetical, beautiful, and transient. the ephemeræ are saved by his means from a slow and lingering death in the evening, and killed in a moment, when they have known nothing of life but pleasure. he is the constant destroyer of insects--the friend of man; and, with the stork and the ibis, may be regarded as a sacred bird. his instinct, which gives him his appointed seasons, and teaches him always when and where to move, may be regarded as flowing from a divine source; and he belongs to the oracles of nature, which speak the awful and intelligible language of a present deity." _poietes_ considers a full and clear river as the most poetical object in nature.--"i will not fail to obey your summons. pliny has, as well as i recollect, compared a river to human life. i have never read the passage in his works; but i have been a hundred times struck with the analogy, particularly amidst mountain scenery. the river, small and clear in its origin, gushes forth from rocks, falls into deep glens, and wantons and meanders through a wild and picturesque country, nourishing only the uncultivated tree or flower by its dew or spray. in this, its state of infancy and youth, it may be compared to the human mind, in which fancy and strength of imagination are predominant--it is more beautiful than useful. when the different rills or torrents join, and descend into the plain, it becomes slow and stately in its motions; it is applied to move machinery, to irrigate meadows, and to bear upon its bosom the stately barge;--in this mature state it is deep, strong, and useful. as it flows on towards the sea, it loses its force and its motion, and at last, as it were, becomes lost, and mingled with the mighty abyss of waters." _halieus_ adds--"one might pursue the metaphor still farther, and say, that in its origin--its thundering and foam, when it carries down clay from the bank, and becomes impure, it resembles the youthful mind, affected by dangerous passions. and the influence of a lake, in calming and clearing the turbid water, may be compared to the effect of reason in more mature life, when the tranquil, deep, cool, and unimpassioned mind is freed from its fever, its troubles, bubbles, noise, and foam. and, above all, the sources of a river--which may be considered as belonging to the atmosphere--and its termination in the ocean, may be regarded as imaging the divine origin of the human mind, and its being ultimately returned to, and lost in, the infinite and eternal intelligence from which it originally sprang." _halieus_ offers some curious observations with respect to the recollection of fish being associated with surrounding objects. "i have known a fish that i have pricked retain his station in the river, and refuse the artificial fly, day after day, for weeks together; but his memory may have been kept awake by this practice, and the recollection seems local, and associated with surrounding objects; and if a pricked trout is chased into another pool, he will, i believe, soon again take the artificial fly. or, if the objects around him are changed, as in autumn, by the decay of weeds, or by their being cut, the same thing happens; and a flood or a rough wind, i believe, assists the fly-fisher, not merely by obscuring the vision of the fish, but, in a river much fished, by changing the appearance of their haunts: large trouts almost always occupy particular stations, under, or close to, a large stone or tree; and probably, most of their recollected sensations are connected with this dwelling. "_physicus._--i think i understand you, that the memory of the danger and pain does not last long, unless there is a permanent sensation with which it can remain associated,--such as the station of the trout; and that the recollection of the mere form of the artificial fly, without this association, is evanescent. "_ornither._--you are diving into metaphysics; yet, i think, in fowling, i have observed that the memory of birds is local. a woodcock that has been much shot at and scared in a particular wood, runs to the side where he has usually escaped, the moment he hears the dogs; but if driven into a new wood, he seems to lose his acquired habits of caution, and becomes stupid." in alluding to the migrations of fishes, _physicus_ observes, "that he has always considered that the two great sources of change of place of animals, was the providing of food for themselves, and resting-places and food for their young. the great supposed migrations of herrings from the poles to the temperate zone appear to be only the approach of successive shoals from deep to shallow water, for the purpose of spawning. the migrations of salmon and trout are evidently for the purpose of depositing their ova, or of finding food after they have spawned." in explaining the circumstances which render a migration into shallow water necessary for the developement of the ova, davy evidently bears in mind the result of his very first experiment.[ ] [ ] vol. i. page . "carp, perch, and pike, deposit their ova in still water, in spring and summer, _when it is supplied with air by the growth of vegetables; and it is to the leaves of plants, which afford a continual supply of oxygen to the water, that the impregnated eggs usually adhere_." again: "fish in spawning-time always approach great shallows, or shores covered with weeds, _which, in the process of their growth, under the influence of the sunshine, constantly supply pure air to the water in contact with them_." the following passage will afford a good specimen of the familiar dialogue, while it will convey to the reader some curious facts connected with the influence of sunshine. "_halieus._--well, gentlemen, what sport? "_poietes._--the fish are rising every where; but though we have been throwing over them with all our skill for a quarter of an hour, yet not a single one will take; and i am afraid we shall return to breakfast without our prey. "_halieus._--i will try; but i shall go to the other side, where i see a very large fish rising--there!--i have him at the very first throw--land this fish, and put him into the well. now, i have another; and i have no doubt i could take half-a-dozen in this very place, where you have been so long in fishing without success. "_physicus._--you must have a different fly; or, have you some unguent or charm to tempt the fish? "_halieus._--no such thing. if any of you will give me your rod and fly, i will answer for it. i shall have the same success. i take your rod, physicus--and lo! i have a fish! "_physicus._--what can be the reason of this? it is perfectly inexplicable to me. yet poietes seems to throw as light as you do, and as well as he did yesterday. "_halieus._--i am surprised that you, who are a philosopher, cannot discover the reason of this--think a little. "_all._--we cannot. "_halieus._--as you are my scholars, i believe i must teach you. the sun is bright, and you have been, naturally enough, fishing with your backs to the sun, which, not being very high, has thrown the shadows of your rods and yourselves upon the water, and you have alarmed the fish, wherever you have thrown a fly. you see, i have fished with my face towards the sun, and though inconvenienced by the light, have given no alarm. follow my example, and you will soon have sport, as there is a breeze playing on the water. "_physicus._--your sagacity puts me in mind of an anecdote which i remember to have heard respecting the late eloquent statesman, charles james fox; who, walking up bond street from one of the club-houses with an illustrious personage, laid him a wager, that he would see more cats than the prince in his walk, and that he might take which side of the way he liked. when they got to the top, it was found, that mr. fox had seen thirteen cats, and the prince not one. the royal personage asked for an explanation of this apparent miracle, and mr. fox said, 'your royal highness took, of course, the shady side of the way, as most agreeable; i knew that the sunny side would be left to me,--and cats always prefer the sunshine.' "_halieus._--there! poietes, by following my advice, you have immediately hooked a fish; and while you are catching a brace, i will tell you an anecdote, which as much relates to fly-fishing as that of physicus, and affords an elucidation of a particular effect of light. "a manufacturer of carmine, who was aware of the superiority of the french colour, went to lyons for the purpose of improving his process, and bargained with the most celebrated manufacturer in that capital for the acquisition of his secret, for which he was to pay a thousand pounds. he was shown all the processes, and saw a beautiful colour produced, yet he found not the least difference in the french mode of fabrication and that which he had constantly adopted. he appealed to the manufacturer, and insisted that he must have concealed something. the manufacturer assured him that he had not, and invited him to see the process a second time. he minutely examined the water and the materials, which were the same as his own, and, very much surprised, said, 'i have lost my labour and my money, for the air of england does not permit us to make good carmine.'--'stay,' says the frenchman, 'do not deceive yourself; what kind of weather is it now?'--'a bright, sunny day,' said the englishman.--'and such are the days,' said the frenchman, 'on which i make my colour. were i to attempt to manufacture it on a dark or cloudy day, my result would be the same as yours. let me advise you, my friend, always to make carmine on bright and sunny days.'--'i will,' says the englishman, 'but i fear i shall make very little in london.' "_poietes._--your anecdote is as much to the purpose as physicus's; yet i am much obliged to you for the hint respecting the effect of shadow, for i have several times, in may and june, had to complain of too clear a sky, and wished, with cotton, for 'a day with not too bright a beam; a warm, but not a scorching sun.'" a very amusing and philosophical conversation on those natural phenomena, which have been vulgarly viewed as prophetic of dry or wet weather, may be well adduced as illustrative of that genius which, by the aid of a light of its own, imparts to the most trite objects all the charms of novelty. "_poietes._--i hope we shall have another good day to-morrow, for the clouds are red in the west. "_physicus._--i have no doubt of it, for the red has a tint of purple. "_halieus._--do you know why this tint portends fine weather? "_physicus._--the air when dry, i believe, refracts more red, or heat-making rays; and as dry air is not perfectly transparent, they are again reflected in the horizon. i have generally observed a coppery or yellow sunset to foretell rain; but, as an indication of wet weather approaching, nothing is more certain than a halo round the moon, which is produced by the precipitated water; and the larger the circle, the nearer the clouds, and consequently the more ready to fall. "_halieus._--i have often observed, that the old proverb is correct-- 'a rainbow in the morning is the shepherd's warning; a rainbow at night is the shepherd's delight.' --can you explain this omen? "_physicus._--a rainbow can only occur when the clouds containing or depositing the rain are opposite to the sun; and in the evening the rainbow is in the east, and in the morning in the west; and as our heavy rains in this climate are usually brought by the westerly wind, a rainbow in the west indicates that the bad weather is on the road, by the wind, to us; whereas the rainbow in the east proves, that the rain in these clouds is passing from us. "_poietes._--i have often observed, that when the swallows fly high, fine weather is to be expected or continued; but when they fly low and close to the ground, rain is almost surely approaching. can you account for this? "_halieus._--swallows follow the flies and gnats, and flies and gnats usually delight in warm strata of air; and as warm air is lighter, and usually moister than cold air, when the warm strata of air are high, there is less chance of moisture being thrown down from them by the mixture with cold air; but when the warm and moist air is close to the surface, it is almost certain, that as the cold air flows down into it, a deposition of water will take place. "_poietes._--i have often seen sea-gulls assemble on the land, and have almost always observed, that very stormy and rainy weather was approaching. i conclude that these animals, sensible of a current of air approaching from the ocean, retire to the land to shelter themselves from the storm. "_ornither._--no such thing. the storm is their element; and the little petrel enjoys the heaviest gale; because, living on the smaller sea insects, he is sure to find his food in the spray of a heavy wave. and you may see him flitting above the edge of the highest surge. i believe that the reason of the migration of sea-gulls and other sea birds to the land, is their security of finding food. they may be observed, at this time, feeding greedily on the earth worms and larvæ driven out of the ground by severe floods; and the fish on which they prey in fine weather in the sea, leave the surface when storms prevail, and go deeper. the search after food, as we agreed on a former occasion, is the principal cause why animals change their places. the different tribes of the wading birds always migrate when rain is about to take place; and i remember once in italy having been long waiting, in the end of march, for the arrival of the double snipe in the campagna of rome: a great flight appeared on the rd of april, and the day after heavy rain set in, which greatly interfered with my sport. the vulture, upon the same principle, follows armies; and i have no doubt, that the augury of the ancients was a good deal founded upon the observation of the instincts of birds. there are many superstitions of the vulgar owing to the same source. for anglers, in spring, it is always unlucky to see _single_ magpies; but _two_ may be always regarded as a favourable omen; and the reason is, that in cold and stormy weather, one magpie alone leaves the nest in search of food, the other remaining sitting upon the eggs or the young ones; but when two go out together, the weather is warm and mild, and thus favourable for fishing. "_poietes._--the singular connexions of cause and effect, to which you have just referred, make superstition less to be wondered at, particularly amongst the vulgar; and when two facts, naturally unconnected, have been accidentally coincident, it is not singular that this coincidence should have been observed and registered, and that omens of the most absurd kind should be trusted in. in the west of england, half a century ago, a particular hollow noise on the sea-coast was referred to a spirit or goblin, called bucca, and was supposed to foretell a shipwreck; the philosopher knows, that sound travels much faster than currents in the air--and the sound always foretold the approach of a very heavy storm, which seldom takes place on that wild and rocky coast, surrounded as it is by the atlantic, without a shipwreck on some part of its extensive shores.[ ] [ ] davy might also have adduced an equally striking superstition, in illustration of his subject, from the cornish mines. the miners not unfrequently hear the echo of their own pickaxes, which they attribute to little fairies at work, and consider it as a happy omen. they say upon such occasions, that there will be good luck, as the piskeys are at work. it is well known that the echo depends upon some cavity in the vicinity of the workmen,--and a cavity, or vogue, is always an indication of subterranean wealth. "_physicus._--all the instances of omens you have mentioned are founded on reason; but how can you explain such absurdities as friday being an unlucky day, the terror of spilling salt, or meeting an old woman? i knew a man of very high dignity, who was exceedingly moved by these omens, and who never went out shooting without a bittern's claw fastened to his button-hole by a riband--which he thought ensured him good luck. "_poietes._--these, as well as the omens of deathwatches, dreams, &c. are for the most part founded upon some accidental coincidences; but spilling of salt, on an uncommon occasion, may, as i have known it, arise from a disposition to apoplexy, shown by an incipient numbness in the hand, and may be a fatal symptom; and persons dispirited by bad omens sometimes prepare the way for evil fortune; for confidence in success is a great means of insuring it. the dream of brutus, before the field of philippi, probably produced a species of irresolution and despondency, which was the principal cause of his losing the battle; and i have heard, that the illustrious sportsman, to whom you referred just now, was always observed to shoot ill, because he shot carelessly, after one of his dispiriting omens. "_halieus._--i have in life met with a few things which i found it impossible to explain, either by chance, coincidences, or by natural connexions; and i have known minds of a very superior class affected by them,--persons in the habit of reasoning deeply and profoundly. "_physicus._--in my opinion, profound minds are the most likely to think lightly of the resources of human reason; it is the pert, superficial thinker who is generally strongest in every kind of unbelief. the deep philosopher sees chains of causes and effects so wonderfully and strangely linked together, that he is usually the last person to decide upon the impossibility of any two series of events being independent of each other; and in science, so many natural miracles, as it were, have been brought to light,--such as the fall of stones from meteors in the atmosphere, the disarming a thunder-cloud by a metallic point, the production of fire from ice by a metal white as silver, and referring certain laws of motion of the sea to the moon,--that the physical enquirer is seldom disposed to assert, confidently, on any abstruse subjects belonging to the order of natural things, and still less so on those relating to the more mysterious relations of moral events and intellectual natures." old isaac walton has amused us with a variety of absurd fables and superstitions: the author of salmonia, on the other hand, touches, as with the spear of ithuriel, the monsters and prodigies of the older writers, and they at once assume the forms of well-ascertained animals, or vegetables. the _sea snake_ seen by american and norwegian captains, appears as a company of porpoises, which in their gambols, by rising and sinking in lines, would give somewhat the appearance of the coils of a snake. the _kraken_, or island fish, is reduced into an assemblage of _urticæ marinæ_, or sea blubbers. the _mermaid_, into the long-haired seal;[ ] and lastly, the celebrated caithness mermaid assumes the unpoetical form of a stout young traveller;--but this story is far too amusing to be dismissed with a passing notice. [ ] a pretended mermaid was exhibited some time since in london, said to have been caught in the chinese seas. it was soon discovered to have been manufactured by joining together the head and bust of two different apes to the lower part of a kipper salmon, which had the fleshy fin, and all the distinct characters of the _salmo salar_. "a worthy baronet, remarkable for his benevolent views and active spirit, has propagated a story of this kind, and he seems to claim for his native country the honour of possessing this extraordinary animal; but the mermaid of caithness was certainly a _gentleman_, who happened to be travelling on that wild shore, and who was seen bathing by some young ladies at so great a distance, that not only _genus_ but gender was mistaken. i am acquainted with him, and have had the story from his own mouth. he is a young man, fond of geological pursuits, and one day in the middle of august, having fatigued and heated himself by climbing a rock to examine a particular appearance of granite, he gave his clothes to his highland guide, who was taking care of his pony, and descended to the sea. the sun was just setting, and he amused himself for some time by swimming from rock to rock, and having unclipped hair and no cap, he sometimes threw aside his locks, and wrung the water from them on the rocks. he happened the year after to be at harrowgate, and was sitting at table with two young ladies from caithness, who were relating to a wondering audience the story of the mermaid they had seen, which had already been published in the newspapers: they described her, as she usually is described by poets, as a beautiful animal with remarkably fair skin and long green hair. the young gentleman took the liberty, as most of the rest of the company did, to put a few questions to the elder of the two ladies,--such as, on what day and precisely where this singular phenomenon had appeared. she had noted down not merely the day, but the hour and minute, and produced a map of the place. our bather referred to his journal, and showed that a human animal was swimming in the very spot at that very time, who had some of the characters ascribed to the mermaid, but who laid no claim to others, particularly the green hair and fish's tail, but, being rather sallow in the face, was glad to have such testimony to the colour of his body beneath his garments." with this story, i must conclude my review of "salmonia,"--a work of considerable scientific and popular interest, and which cannot fail to become the favourite companion of the philosophical angler. the only production with which it can be at all compared is that of the "complete angler, by izaac walton." i agree with the critic who regards the two authors as pilgrims bound for the same shrine, resembling each other in their general habit--the scalloped hat, the dalmatique, and the knobbed and spiked staff--which equalize all who assume the character; yet, though alike in purpose, dress, and demeanour, the observant eye can doubtless discern an essential difference betwixt those devotees. the burgess does not make his approach to the shrine with the stately pace of a knight or a noble; the simple and uninformed rustic has not the contemplative step of the philosopher, or the quick glance of the poet. the palm of originality and of exquisite simplicity, which cannot perhaps be imitated with entire success, must remain with the common father of anglers--the patriarch izaac; but it would be absurd to compare his work with the one written by the most distinguished philosopher of the nineteenth century, whose genius, like a sunbeam, illumined every recess which it penetrated, imparting to scarcely visible objects, definite forms and various colours. if the advanced age of walton was pleaded by himself as a sufficient reason for procuring "_a writ of ease_," the friends of davy may surely claim at the hands of the critic an indulgent reception for a congenial work written in the hour of bodily lassitude and sickness. this benevolent feeling, however, did not penetrate every heart. a passage, which i shall presently quote, appears to have given great offence to the president of the mechanics' institute, and to have been considered by him as the indication of a covert hostility to the spread of knowledge. the earth had scarcely closed upon the remains of the philosopher, when, in his anniversary speech,[ ] the autocrat of all the mechanics, availing himself of this pretext, assailed his character with the charge of "conceit, pride, and arrogance." [ ] see a report of the president's speech, at the sixth anniversary of the mechanics' institute, as reported in all the journals of the day, december , . the following is the passage in salmonia, which provoked this angry and unjust philippic. "i am sorry to say, i think the system carried too far in england. god forbid, that any useful light should be extinguished! let the persons who wish for education receive it; but it appears to me that, in the great cities in england, it is, as it were, forced upon the population; and that sciences, which the lower classes can only very superficially acquire, are presented to them; in consequence of which they often become idle and conceited, and above their usual laborious occupations. the unripe fruit of the tree of knowledge is, i believe, always bitter or sour; and scepticism and discontentment--sicknesses of the mind--are often the result of devouring it." methinks i hear the reader exclaim--"how little could davy imagine that his prophetic words would have been so soon fulfilled!"--but i would seriously recommend to the president of the mechanics' institute, an anecdote which, if properly applied, cannot fail to be instructive.--when diogenes, trampling with his dirty feet on the embroidered couch of plato, cried out--"_thus do i trample on the pride of plato!_" the philosopher shook his head, and replied--"_truly, but with more pride thou dost it, good diogenes._" chapter xv. sir h. davy's paper on the phenomena of volcanoes.--his experiments on vesuvius.--theory of volcanic action.--his reception abroad.--anecdotes.--his last letter to mr. poole from rome.--his paper on the electricity of the torpedo.--consolations in travel, or the last days of a philosopher.--analysis of the work.--reflections suggested by its style and composition.--davy and wollaston compared.--his last illness.--arrival at geneva.--his death. a short time before sir humphry davy quitted england, to which he was destined never to return, he communicated to the royal society a paper "on the phenomena of volcanoes;" which was read on the th of march , and published in the transactions of that year. the object of this memoir was to collect and record the various observations and experiments which he had made on vesuvius, during his several visits to that volcano. the appearances which it presented in and have been already noticed; it was in december , and during the two succeeding months, that the mountain offered a favourable opportunity for making those experiments which form the principal subject of the present communication. it was a point of great importance to determine whether any combustion was going on at the moment the lava issued from the mountain; for this fact being once discovered, and the nature of the combustible matter ascertained, we should gain an immense step towards a just theory of the sources of volcanic action. for this purpose, he carefully examined both the lava and the elastic fluids with which it was accompanied. he was unable, however, to detect any thing like deflagration with nitre, which must have taken place had the smallest quantity of carbonaceous matter been present; nor could he, by exposing the ignited mass to portions of atmospheric air, discover that any appreciable quantity of oxygen had been absorbed. on immersing fused lava in water, no decomposition of that fluid followed, so that there could not have existed any quantity of the metallic bases of the alkalies or earths. common salt, chloride of iron, the sulphates and muriates of potash, and soda, generally constituted the mass of solid products; while steam, muriatic acid fumes, and occasionally sulphurous acid vapours, formed the principal elastic matters disengaged. he informs us it was on the th of january , that he had the honour to accompany his royal highness the prince of denmark in an excursion to the mountain, on which occasion his friend, cavalier monticelli, was also present. at this time, the lava was seen nearly white hot through a chasm near the place where it flowed from the mountain; and yet, although he threw nitre upon it in large quantities through this chasm, there was no more increase of ignition than when the experiment was made on lava exposed to the free air. he observed that the appearance of the sublimations was very different from that which they had presented on former occasions; those near the aperture were coloured green and blue by salt of copper; but there was, as usual, a great quantity of muriate of iron. on the th, the sublimate of the lava was pure chloride of sodium; in the sublimate of january th, there were both sulphate of soda and indications of sulphate of potash; but in those which he collected during this last visit, the sulphate of soda was in much larger quantities, and there was much more of a salt of potash. for nearly three months the craters, of which there were two, were in activity. the larger one threw up showers of ignited ashes and stones to a height apparently of from two hundred to two hundred and fifty feet; and from the smaller crater steam arose with great violence. whenever the crater could be approached, it was found incrusted with saline matter: and the walk to the edge of the small crater, on the th of january, was through a mass of loose saline matter, principally common salt coloured by muriate of iron, in which the foot sunk to some depth. it was easy, even at a great distance, to distinguish between the steam disengaged by one of the craters, and the earthy matter thrown up by the other. the steam appeared white in the day, and formed perfectly white clouds, which reflected the morning and evening light of the purest tints of red and orange. the earthy matter always appeared as a black smoke, forming dark clouds, and in the night it was highly luminous at the moment of the explosion. he concludes this paper on volcanoes with some observations on the theory of their phenomena. "it appears," says he, "almost demonstrable, that none of the chemical causes anciently assigned for volcanic fires can be true. amongst these, the combustion of mineral coal is one of the most current; but it seems wholly inadequate to account for the phenomena. however large the stratum of pit-coal, its combustion under the surface could never produce violent and excessive heat; for the production of carbonic acid gas, when there was no free circulation of air, must tend constantly to impede the process: and it is scarcely possible that carbonaceous matter, if such a cause existed, should not be found in the lava, and be disengaged with the saline or aqueous products from the bocca or craters. there are many instances in england of strata of mineral coal which have been long burning; but the results have been merely baked clay and schists, and it has produced no result similar to lava. "if the idea of lemery were correct, that the action of sulphur on iron may be a cause of volcanic fires, sulphate of iron ought to be the great product of the volcano; which is known not to be the case; and the heat produced by the action of sulphur on the common metals is quite inadequate to account for the appearances. when it is considered that volcanic fires occur and intermit with all the phenomena that indicate intense chemical action, it seems not unreasonable to refer them to chemical causes. but for phenomena upon such a scale, an immense mass of matter must be in activity, and the products of the volcano ought to give an idea of the nature of the substances primarily active. now, what are these products? mixtures of the earths in an oxidated and fused state, and intensely ignited; water and saline substances, such as might be furnished by the sea and air, altered in such a manner as might be expected from the formation of fixed oxidated matter. but it may be said, if the oxidation of the metals of the earths be the causes of the phenomena, some of these substances ought occasionally to be found in the lava, or the combustion ought to be increased at the moment the materials passed into the atmosphere. but the reply to this objection is, that it is evident that the changes which occasion volcanic fires take place in immense subterranean cavities; and that the access of air to the acting substances occurs long before they reach the exterior surface. "there is no question but that the ground under the solfaterra is hollow; and there is scarcely any reason to doubt of a subterraneous communication between this crater and that of vesuvius: whenever vesuvius is in an active state, the solfaterra is comparatively tranquil. i examined the bocca of the solfaterra on the st of february , two days before the activity of vesuvius was at its height: the columns of steam which usually arise in large quantities when vesuvius is tranquil, were now scarcely visible, and a piece of paper thrown into the aperture did not rise again; so that there was every reason to suppose the existence of a descending current of air. the subterraneous thunder heard at such great distances under vesuvius is almost a demonstration of the existence of great cavities below filled with aëriform matter: and the same excavations which, in the active state of the volcano, throw out, during so great a length of time, immense volumes of steam, must, there is every reason to believe, in its quiet state, become filled with atmospheric air.[ ] [ ] "vesuvius is a mountain admirably fitted, from its form and situation, for experiments on the effect of its attraction on the pendulum: and it would be easy in this way to determine the problem of its cavities. on etna the problem might be solved on a larger scale." "to what extent subterraneous cavities may exist, even in common rocks, is shown in the limestone caverns of carniola, some of which contain many hundred thousand cubical feet of air; and in proportion as the depth of an excavation is greater, so is the air more fit for combustion. "the same circumstances which would give alloys of the metals of the earths the power of producing volcanic phenomena, namely, their extreme facility of oxidation, must likewise prevent them from ever being found in a pure combustible state in the products of volcanic eruptions; for before they reach the external surface, they must not only be exposed to the air in the subterranean cavities, but be propelled by steam; which must possess, under the circumstances, at least the same facility of oxidating them as air. assuming the hypothesis of the existence of such alloys of the metals of the earths as may burn into lava in the interior, the whole phenomena may be easily explained from the action of the water of the sea and air on those metals; nor is there any fact, or any of the circumstances which i have mentioned in the preceding part of this paper, which cannot be easily explained according to that hypothesis. for almost all the volcanoes in the old world of considerable magnitude are near, or at no considerable distance from the sea: and if it be assumed that the first eruptions are produced by the action of sea-water upon the metals of the earths, and that considerable cavities are left by the oxidated metals thrown out as lava, the results of their action are such as might be anticipated; for, after the first eruptions, the oxidations which produce the subsequent ones may take place in the caverns below the surface; and when the sea is distant, as in the volcanoes of south america, they may be supplied with water from great subterranean lakes, as humboldt states that some of them throw up quantities of fish. "on the hypothesis of a chemical cause for volcanic fires, and reasoning from known facts, there appears to me no other adequate source than the oxidation of the metals which form the bases of the earths and alkalies; but it must not be denied, that considerations derived from thermometrical experiments on the temperature of mines and of sources of hot water, render it probable that the interior of the globe possesses a very high temperature: and the hypothesis of the nucleus of the globe being composed of fluid matter offers a still more simple solution of the phenomena of volcanic fires than that which has been just developed." it must be admitted that the concluding sentence of this memoir is rather equivocal. he states that the metalloidal theory of volcanoes is most chemical, but that the hypothesis which assumes the high temperature of the interior of the globe is the most simple; but he leaves us in doubt as to his own belief upon the subject. in his "last days," however, we shall find that he offers a less reserved opinion upon this question. * * * * * with respect to sir humphry davy's last journey to rome, i have nothing of particular interest to relate. universally known and respected, a member of almost every scientific society in europe, there was not a part of the continent in which he felt as a stranger in a foreign land. i might, in addition to the circumstances which have been already mentioned, relate several anecdotes in proof of the widely-extended popularity which his genius and discoveries had secured for him. the following striking incidents deserve particular notice.--whilst sporting in austria, he was assaulted by some peasants; and the outrage was no sooner made known to the emperor, than he expressed his sorrow and indignation in the strongest language, and immediately directed that a party of troops should surround the district, and a most rigorous search be made for the culprits. the search was of course successful, and the "carinthian boors" received merited chastisement. for the following anecdote i am indebted to lady davy. her ladyship was travelling alone, on account of ill health, and upon arriving at basle, she naturally felt a strong desire to visit its far-famed library; it so happened, however, that sunday was the only day which afforded her this opportunity, and so strictly is the sabbath observed at that place, that she was at once informed that an admission to the library, under any circumstances, was altogether impossible. she nevertheless addressed a note to the librarian, stating to him her name, and the reasons for her unusual request. he immediately returned an answer, and appointed the hour of ten for her visit. having shown her all that deserved inspection, he concluded his attentions by saying, "madam, i have held the keys of this library for thirty years, during which period only three persons have been admitted to see its treasures on the sunday; two of these were crowned heads, the third the wife of the most celebrated philosopher in europe." the following is the last letter which davy ever wrote to his much-valued friend mr. poole.-- to thomas poole, esq. my dear poole, rome, feb. , . i have not written to you during my absence from england, because i had no satisfactory account of any marked progress towards health to give you, and the feelings of an invalid are painful enough for himself, and should, i think, never form a part of his correspondence; for they are not diminished by the conviction that they are felt by others. would i were better! i would then write to you an agreeable letter from this glorious city; but i am here _wearing away_ the winter; a ruin amongst ruins! i am anxious to hear from you,--very anxious, so pray write to me with this address, "sir h. davy, inglese, posta restanti, rovigo, italia." you know you must pay the postage to the frontier, otherwise the letters, like one a friend sent to me, will go back to you. pray be so good as to be particular in the direction,--the "inglese" is necessary. i hope you got a copy of my little trifle "_salmonia_." i ordered copies to be sent to you, to mr. w----, and to mr. baker: but as the course of letters in foreign countries is uncertain, i am not sure you received them; if not, you will have lost little; a _second edition_ will soon be out, which will be in every respect more worthy of your perusal, being, i think, twice (not saying much for it) as entertaining and philosophical. i will take care by early orders that you have this book. i write and philosophize a good deal, and have nearly finished a work with a higher aim than the little book i speak of above, and which i shall dedicate to you. it contains the essence of my philosophical opinions, and some of my poetical reveries. it is, like the "salmonia," an amusement of my sickness; but "_paulo majora canamus_." i sometimes think of the lines of waller, and seem to feel their truth: "the soul's dark cottage, batter`d and decay'd, lets in new lights through chinks that time has made." i have, notwithstanding my infirmities, attended to scientific objects whenever it was in my power, and i have sent the royal society a paper which they will publish, on the peculiar electricity of the torpedo, which i think bears remotely upon the functions of life. i attend a good deal to natural history, and i think i have recognised in the mediterranean a _new species of eel_, a sort of link between the conger and the muræna of the ancients. i have no doubt mr. baker is right about the distinction between the conger and the common eel. i am very anxious to hear what he thinks about _their generation_. pray get from him a distinct opinion on this subject. i am at this moment getting the _eels in the markets_ here dissected, and have found _ova_ in plenty. pray tell me particularly what mr. baker has done; this is a favourite subject with me, and you can give me no news so interesting. my dear friend, i shall never forget your kindness to me. you, with one other person, have given me the little happiness i have enjoyed since my severe visitation. i fight against sickness and fate, believing i have still duties to perform, and that even my illness is connected in some way with my being made useful to my fellow-creatures. i have this conviction full on my mind, that intellectual beings spring from the same breath of infinite intelligence, and return to it again, but by different courses. like rivers, born amidst the clouds of heaven, and lost in the deep and eternal ocean--some in youth, rapid and short-lived torrents; some in manhood, powerful and copious rivers; and some in age, by a winding and slow course, half lost in their career, and making their exit through many sandy and shallow mouths. i hope to be at rovigo about the first week in april. i travel slowly and with my own horses. if you will come and join me there, i can give you a place in a comfortable carriage, and can show you the most glorious country in europe--illyria and styria, and take you to the french frontier before the beginning of autumn,--perhaps to england. if you can come, do so at once. i have two servants, and can accommodate you with every thing. i think of taking some baths before i return, in upper austria; but i write as if i were a strong man, when i am like a pendulum, as it were, swinging between death and life. god bless you, my dear poole. your grateful and affectionate friend, h. davy. pray remember me to our friends at stowey. his paper on the electricity of the torpedo, to which he alludes in the foregoing letter, appears to have been written shortly after he had finished his "salmonia," as it is dated from lubiana, illyria, on the th of october, and it was read before the royal society on the th of november , and published in the first part of the transactions for . it will be remembered, that this subject had long engaged his attention; and he expresses his surprise that the electricity of living animals should not have been an object of greater attention, both on account of its physiological importance, and its general relation to the science of electro-chemistry. when volta discovered his wonderful pile, he imagined he had made a perfect resemblance of the organ of the gymnotus and torpedo; and davy observes, that whoever has felt the shocks of the natural and artificial instruments must have been convinced, as far as sensation is concerned, of their strict analogy. after the discovery of the _chemical_ power of the voltaic instrument, he was naturally desirous of ascertaining whether this property was possessed by the electrical organs of living animals; for which purpose, he instituted various experiments, but he could not discover that such was the fact. upon mentioning his researches to signor volta, with whom he passed some time in the summer of , the italian philosopher showed him a peculiar form of his instrument, which appeared to fulfil the conditions of the organs of the torpedo; _viz._ a pile, of which the fluid substance was a very imperfect conductor, such as honey or a strong saccharine extract, which required a certain time to become charged, and which did not decompose water, though it communicated weak shocks. the discovery by oersted of the effects of voltaic electricity on the magnetic needle induced davy to examine whether the electricity of living animals possessed a similar power. having, after some trouble, procured two lively and recently caught torpedoes, he passed the shocks from the largest of these animals a number of times through the circuit of an extremely delicate magnetic electrometer, but, although every precaution was used, not the slightest deviation of, or effect on, the needle could be perceived. "these negative results," says he, "may be explained by supposing that the motion of the electricity in the torpedinal organ is in no measurable time, and that a current of some continuance is necessary to produce the deviation of the magnetic needle; and i found that the magnetic electrometer was equally insensible to the weak discharge of a leyden jar as to that of the torpedinal organ; though whenever there was a continuous current from the smallest surfaces in voltaic combinations of the weakest power, but in which some chemical action was going on, it was instantly and powerfully affected. two series of zinc and silver, and paper moistened in salt and water, caused the permanent deviation of the needle several degrees, though the plates of zinc were only one-sixth of an inch in diameter. "it would be desirable to pursue these enquiries with the electricity of the gymnotus, which is so much more powerful than that of the torpedo; but if they are now to be reasoned upon, they seem to show a stronger analogy between common and animal electricity, than between voltaic and animal electricity; it is however, i think, more probable that animal electricity will be found of a distinctive and peculiar kind. "common electricity is excited upon non-conductors, and is readily carried off by conductors and imperfect conductors. voltaic electricity is excited upon combinations of perfect and imperfect conductors, and is only transmitted by perfect conductors, or imperfect conductors of the best kind. "magnetism, if it be a form of electricity, belongs only to perfect conductors; and, in its modifications, to a peculiar class of them. "the animal electricity resides only in the imperfect conductors forming the organs of living animals, and its object in the economy of nature is to act on living animals. "distinctions might be established in pursuing the various modifications or properties of electricity in these different forms; but it is scarcely possible to avoid being struck by another relation of this subject. the torpedinal organ depends for its powers upon the will of the animal. john hunter has shown how copiously it is furnished with nerves. in examining the columnar structure of the organ of the torpedo, i have never been able to discover arrangements of different conductors similar to those in galvanic combinations, and it seems not improbable that the shock depends upon some property developed by the action of the nerves. "to attempt to reason upon any phenomena of this kind as dependent upon a specific fluid would be wholly vain. little as we know of the nature of electrical action, we are still more ignorant of the nature of the functions of the nerves. there seems, however, a gleam of light worth pursuing in the peculiarities of animal electricity,--its connexion with so large a nervous system, its dependence upon the will of the animal, and the instantaneous nature of its transfer, which may lead, when pursued by adequate enquirers, to results important for physiology." he concludes this paper by expressing his fear that the weak state of his health will prevent him from following the subject with the attention it seems to deserve; and he therefore communicates these imperfect trials to the royal society, in the hope that they may lead to more extensive and profound researches. we come now to the consideration of the last production of his genius--"consolations in travel, or the last days of a philosopher:" a work which, he informs us in the preface, was composed immediately after salmonia, under the same unfavourable and painful circumstances, and at a period when his constitution suffered from new attacks. from this exercise of the mind, he tells us, that he derived some pleasure and some consolation, when most other sources of consolation and pleasure were closed to him; and he ventures to hope that those hours of sickness may be not altogether unprofitable to persons in perfect health. his brother, dr. davy, who edited the work after the decease of sir humphry, informs us that it was concluded at the very moment of the invasion of the author's last illness, and that, had his life been prolonged, it is probable some additions and some changes would have been made. "the characters of the persons of the dialogue," continues the editor, "were intended to be ideal, at least in great part;--such they should be considered by the reader; and it is to be hoped, that the incidents introduced, as well as the persons, will be viewed only as subordinate and subservient to the sentiments and the doctrines. the dedication, it may be specially noticed, is the author's own, and in the very words dictated by himself at a time when he had lost the power of writing, except with extreme difficulty, owing to the paralytic attack, although he retained in a very remarkable manner all his mental faculties unimpaired and unclouded." the words of the dedication are "to thomas poole, esq. of nether stowey; in remembrance of thirty years of continued and faithful friendship." this is a most extraordinary and interesting work: extraordinary, not only from the wild strength of its fancy, and the extravagance of its conceptions, but from the bright light of scientific truth which is constantly shining through its metaphorical tissue, and irradiating its most shadowy imaginings. it may be compared to the tree of the lower regions in the Æneid, to every leaf of which was attached a dream; and yet, however wildly his fancy may dream, his philosophy never sleeps; and in his exit from the land of phantoms, the author can in no instance be accused of having mistaken the gate of ivory for that of horn. to the biographer, the work is of the highest interest and value, by confirming, in a remarkable manner, the opinion so frequently expressed in the course of these memoirs, with respect to the diversified talents of sir humphry davy; and above all, by elucidating that rare combination of imagination with judgment, which imparted to his genius its more striking peculiarities. the work consists of six dialogues:-- . the vision; . discussions connected with the vision in the colosÆum; . the unknown; . the proteus, or immortality; . the chemical philosopher; and . pola, or time. the interlocutors of the first dialogue are two intellectual englishmen, one of whom the author calls _ambrosio_; a man of highly cultivated taste, great classical erudition, and minute historical knowledge: a catholic in religion, but so liberal in his sentiments, that in another age he might have been secretary to ganganelli. the other friend, whom he calls _onuphrio_, was a man of a very different character: belonging to the english aristocracy, he had some of the prejudices usually attached to birth and rank; but his manners were gentle, his temper good, and his disposition amiable. having been partly educated at a northern university in britain, he had adopted views in religion which went even beyond toleration, and which might be regarded as entering the verge of scepticism. for a patrician, he was very liberal in his political views. his imagination was poetical and discursive, his taste good, and his tact extremely fine,--so exquisite, indeed, that it sometimes approached to morbid sensibility, and disgusted him with slight defects, and made him keenly sensible of small perfections to which common minds have been indifferent. the author, with these his two friends, makes an excursion to the colosæum, and the conversation, which a view of those magnificent ruins produced, together with the account of a dream, or vision, which occurred to him while left alone amidst these mouldering monuments, forms the subject-matter of the first dialogue. it is impossible for any person of the least imagination to contemplate this decay of former magnificence without strong emotion; but the direction and tone of such feeling will be necessarily modified by the qualities of the mind in which it is excited; and the author has therefore very properly assigned to each of the _dramatis personæ_, such opinions as might best correspond with his character and temperament. they are all represented as being struck with the transiency of human monuments; but _ambrosio_ views with triumph the sanctifying influence of a few crosses planted around the ruins, in arresting the farther decay of the pile. "without the influence of christianity," he exclaims, "these majestic ruins would have been dispersed or levelled to the dust. plundered of their lead and iron by the barbarians, goths and vandals, and robbed even of their stones by roman princes--the barberini, they owe what remains of their relics to the sanctifying influence of that faith which has preserved for the world all that was worth preserving, not merely arts and literature, but likewise that which constitutes the progressive nature of intellect, and the institutions which afford to us happiness in this world, and hopes of a blessed immortality in the next." and he continues,--"what a contrast the present application of this building, connected with holy feelings and exalted hopes, is to that of the ancient one, when it was used for exhibiting to the roman people the destruction of men by wild beasts, or of men more savage than wild beasts by each other, to gratify a horrible appetite for cruelty, founded upon a still more detestable lust, that of universal domination! and who would have supposed, in the time of titus, that a faith, despised in its insignificant origin, and persecuted from the supposed obscurity of its founder and its principles, should have reared a dome to the memory of one of its humblest teachers, more glorious than was ever framed for jupiter or apollo in the ancient world, and have preserved even the ruins of the temples of the pagan deities, and have burst forth in splendour and majesty, consecrating truth amidst the shrines of error, employing the idols of the roman superstition for the most holy purposes, and rising a bright and constant light amidst the dark and starless night which followed the destruction of the roman empire!" it was not to be expected that _onuphrio_, whose views are represented as verging upon scepticism, should have tacitly coincided in these opinions of _ambrosio_. he admits, indeed, that some little of the perfect state in which these ruins exist may have been owing to the causes just described; but these causes, he maintains, have only lately begun to operate, and the mischief was done before christianity was established at rome. "feeling differently on these subjects," says he, "i admire this venerable ruin rather as the record of the destruction of the power of the greatest people that ever existed, than as a proof of the triumph of christianity; and i am carried forward, in melancholy anticipation, to the period when even the magnificent dome of st. peter's will be in a similar state to that in which the colosæum now is, and when its ruins may be preserved by the sanctifying influence of some new and unknown faith; when perhaps the statue of jupiter, which at present receives the kiss of the devotee, as the image of st. peter, may be employed for another holy use, as the personification of a future saint or divinity; and when the monuments of the papal magnificence shall be mixed with the same dust as that which now covers the tombs of the cæsars. "such, i am sorry to say, is the general history of all the works and institutions belonging to humanity. they rise, flourish, and then decay and fall; and the period of their decline is generally proportional to that of their elevation. in ancient thebes or memphis, the peculiar genius of the people has left us monuments from which we can judge of their arts, though we cannot understand the nature of their superstitions. of babylon and of troy, the remains are almost extinct; and what we know of those famous cities is almost entirely derived from literary records. ancient greece and rome we view in the few remains of their monuments; and the time will arrive when modern rome shall be what ancient rome now is; and ancient rome and athens will be what tyre or carthage now are, known only by coloured dust in the desert, or coloured sand, containing the fragments of bricks, or glass, washed up by the wave of a stormy sea." for this desponding view of passing events, _onuphrio_ finds consolation in the evidences of revealed religion. in the origin, progress, elevation, decline, and fall of the empires of antiquity, he sees proofs that they were intended for a definite end in the scheme of human redemption; and he finds prophecies which have been amply verified. he regards the foundation or the ruin of a kingdom, which appears in civil history so great an event, as comparatively of small moment in the history of man and in his religious institutions. he considers the establishment of the worship of one god amongst a despised and contemned people, as the most important circumstance in the history of the early world. he regards the christian dispensation as naturally arising out of the jewish, and the doctrines of the pagan nations all preparatory to the triumph and final establishment of a creed fitted for the most enlightened state of the human mind, and equally adapted to every climate and every people. we cannot but regard these passages with great interest, as indicating the train of thought which must have occupied the mind of their author, and as proving that, in his latter days, he not only studied the doctrines of christianity, but derived the greatest consolation from its tenets. after some farther conversation, _onuphrio_ and _ambrosio_ leave their friend the author to pursue his meditations amidst the solitude of the ruins. seated in the moonshine on one of the steps leading to the seats supposed to have been occupied by the patricians in the colosæum at the time of the public games, the train of ideas in which he had before indulged continued to flow with a vividness and force increased by the stillness and solitude of the scene, and by the full moon, which, he observes, has always a peculiar effect on these moods of feeling in his mind, giving to them a wildness and a kind of indefinite sensation, such as he supposes belong at all times to the true poetical temperament. "it must be so," thought he, "no new city will rise again out of the double ruins of this; no new empire will be founded upon these colossal remains of that of the old romans. the world, like the individual, flourishes in youth, rises to strength in manhood, falls into decay in age; and the ruins of an empire are like the decrepid frame of an individual, except that they have some tints of beauty, which nature bestows upon them. the sun of civilization arose in the east, advanced towards the west, and is now at its meridian; in a few centuries more, it will probably be seen sinking below the horizon, even in the new world; and there will be left darkness only where there is a bright light, deserts of sand where there were populous cities, and stagnant morasses where the green meadow, or the bright corn-field once appeared. time," he exclaimed, "which purifies, and, as it were, sanctifies the mind, destroys and brings into utter decay the body; and even in nature its influence seems always degrading. she is represented by the poet as eternal in her youth; but amongst these ruins she appears to me eternal in her age, and here, no traces of renovation appear in the ancient of days." he had scarcely concluded this ideal sentence, when his reverie became deeper, and his imagination called up a spirit, who, having rebuked him for his ignorance and presumption, undeceives him in his views of the history of the world, by unfolding to him in a vision the progress of man from a state of barbarity to that of high civilization. he is first shown a country covered with forests and marshes; wild animals were grazing in large savannahs, and carnivorous beasts, such as lions and tigers, occasionally disturbing and destroying them. man appeared as a naked savage, feeding upon wild fruits, or devouring shell-fish, or fighting with clubs for the remains of a whale which had been thrown upon the shore. his habitation was a cave in the earth--"see the birth of time!" exclaimed the genius; "look at man in his newly-created state, full of youth and vigour. do you see aught in this state to admire or envy?" in the next scene, a country opened upon his view, which appeared partly wild and partly cultivated; and men were seen covered with the skins of animals, and driving cattle to enclosed pastures; others were reaping and collecting corn, and others again were making it into bread. cottages appeared furnished with many of the conveniences of life. the genius now said, "look at these groups of men who are escaped from the state of infancy; they owe their improvement to a few superior minds still amongst them. that aged man whom you see with a crowd around him taught them to build cottages; from that other they learnt to domesticate cattle; from others, to collect and sow corn and seeds of fruit. and these arts will never be lost; another generation will see them more perfect. you shall be shown other visions of the passages of time; but as you are carried along the stream which flows from the period of creation to the present moment, i shall only arrest your transit to make you observe some circumstances which will demonstrate the truths i wish you to know." he then proceeds to describe in succession the different scenes as they appeared before him, and to relate the observations by which his genius, or intellectual guide, accompanied him. a great extent of cultivated plains, large cities on the sea-shore, palaces, forums, and temples, were displayed before him. he saw men associated in groups, mounted on horses, and performing military exercises; galleys moved by oars on the ocean; roads intersecting the country covered with travellers, and containing carriages moved by men or horses. the genius now said, "you see the early state of civilization of man: the cottages of the last race you beheld have become improved into stately dwellings, palaces, and temples, in which use is combined with ornament. the few men to whom, as i said before, the foundations of these improvements were owing, have had divine honours paid to their memory. but look at the instruments belonging to this generation, and you will find they were only of brass. you see men who are talking to crowds around them, and others who are apparently amusing listening groups by a kind of song or recitation; these are the earliest bards and orators; but all their signs of thought are oral, for written language does not yet exist." the genius next presented to him a scene of varied business and imagery. he saw a man who bore in his hands the same instruments as our modern smiths, presenting a vase, which appeared to be made of iron, amidst the acclamations of an assembled multitude; and he saw in the same place men who carried rolls of papyrus in their hands, and wrote upon them with reeds containing ink, made from the soot of wood mixed with a solution of glue.--"see," the genius said, "an immense change produced in the condition of society by the two arts of which you now see the origin; the one, that of rendering iron malleable, which is owing to a single individual, an obscure greek; the other, that of making thought permanent in written characters,--an art which has gradually arisen from the hieroglyphics which you may observe on yonder pyramids. you will now see human life more replete with power and activity." in the scenes that succeeded, he saw bronze instruments thrown away; malleable iron converted into hard steel, and applied to a thousand purposes of civilized life; bands of men traversing the sea, founding colonies, building cities, and, wherever they established themselves, carrying with them their peculiar arts. he saw the roman world succeeded by cities filled with an idle and luxurious population, and the farms which had been cultivated by warriors, who left the plough to take the command of armies, now in the hands of slaves; and the militia of free men supplanted by bands of mercenaries, who sold the empire to the highest bidder. he saw immense masses of warriors collecting in the north and east, carrying with them no other proofs of cultivation but their horses and steel arms. he saw these savages every where plundering cities and destroying the monuments of arts and literature. ruin, desolation, and darkness were before him, and he closed his eyes to avoid the melancholy scene. "see," said the genius, "the termination of a power believed by its founders invincible, and intended to be eternal. but you will find, though the glory and greatness belonging to its military genius have passed away, yet those belonging to the arts and institutions by which it adorned and dignified life, will again arise in another state of society." upon again opening his eyes, he saw italy recovering from her desolation, towns arising with governments almost upon the model of ancient athens and rome, and these different small states rivals in arts and arms;--he saw the remains of libraries, which had been preserved in monasteries and churches by a holy influence, which even the goth and vandal respected, again opened to the people;--he saw rome rising from her ashes, the fragments of statues found amidst the ruins of her palaces and imperial villas, becoming the models for the regeneration of art;--he saw magnificent temples raised in this city, become the metropolis of a new and christian world, and ornamented with the most brilliant master-pieces of the arts of design.--"now," the genius said, "society has taken its modern and permanent aspect. consider for a moment its relations to letters and to arms, as contrasted with those of the ancient world." he looked, and he saw that, in the place of the rolls of papyrus, libraries were now filled with books. "behold," the genius said, "the printing press! by the invention of faust, the productions of genius are, as it were, made imperishable, capable of indefinite multiplication, and rendered an unalienable heritage of the human mind. by this art, apparently so humble, the progress of society is secured, and man is spared the humiliation of witnessing again scenes like those which followed the destruction of the roman empire. now look to the warriors of modern times; you see the spear, the javelin, and the cuirass are changed for the musket and the light artillery. the german monk who discovered gunpowder did not meanly affect the destinies of mankind; wars are become less bloody by becoming less personal; mere brutal strength is rendered of comparatively little avail; all the resources of civilization are required to move a large army; wealth, ingenuity, and perseverance become the principal elements of success; civilized man is rendered in consequence infinitely superior to the savage, and gunpowder gives permanence to his triumph, and secures the cultivated nations from being ever again overrun by the inroads of millions of barbarians."[ ] [ ] this is a question which gibbon has very eloquently discussed ("_general observations on the fall of the roman empire in the west_," vol. vi.) "cannon and fortifications now form an impregnable barrier against the tartar horse; and europe is secure from any future irruption of barbarians; since, before they can conquer, they must cease to be barbarous." what an extraordinary illustration does this principle find in the history of our possessions in india, where, to speak in round numbers, thirty thousand europeans keep no less than one hundred million of natives in subjection! the genius then directs his attention to scenes in which are displayed the triumphs of modern science; such as the steam-engine, and the thousand resources furnished by the chemical and mechanical arts; and she concludes by endeavouring to impress upon him the conviction, "that the results of intellectual labour, or of scientific genius, are permanent, and incapable of being lost. monarchs change their plans, governments their objects, a fleet or an army effect their purpose and then pass away; but a piece of steel touched by the magnet preserves its character for ever, and secures to man the dominion of the trackless ocean. a new period of society may send armies from the shores of the baltic to those of the euxine, and the empire of the followers of mahomet may be broken in pieces by a northern people, and the dominion of the britons in asia may share the fate of tamerlane or zengis-khan; but the steam-boat which ascends the delaware, or the st. lawrence, will be continued to be used, and will carry the civilization of an improved people into the deserts of north america, and into the wilds of canada. in the common history of the world, as compiled by authors in general, almost all the great changes of nations are confounded with changes in their dynasties, and events are usually referred either to sovereigns, chiefs, heroes, or their armies, which do, in fact, originate from entirely different causes, either of an intellectual or moral nature." having instructed him in the history of man as an inhabitant of the earth, the genius proceeds to reveal to him the mysteries of spiritual natures, in which the author evidently shows his attachment to the belief that our intellectual essence is destined hereafter to enjoy a higher and better state of planetary existence,[ ] drinking intellectual light from a purer source, and approaching nearer to the infinite and divine mind. i shall not attempt to follow him and his genius to the verge of the solar system, witnessing in his career the inhabitants of planets and comets. we may upon this occasion truly apply to the author the words of lucretius-- "processit longe flammantia moenia mundi." "his vigorous and active mind was hurl'd beyond the flaming limits of the world."--creech. in the former part of the dialogue, his poetical coruscations appeared only as brilliant sparks thrown off by the rapidity of the machinery which he worked for a useful end and for a definite purpose; his vivid imagination may now be compared to a display of fire-works, which dazzle and confound without enlightening the senses, and leave the spectator in still more profound darkness. [ ] under the article 'sensation,' in the philosophical dictionary, we find voltaire indulging in a similar speculation. "it may be, that in other globes the inhabitants possess sensations of which we can form no idea. it is possible that the number of our senses augments from globe to globe, and that an existence with innumerable and perfect senses will be the final attainment of all being." his second dialogue, entitled "discussions connected with the vision in the colosæum," may be considered as a commentary upon the views he had unfolded; and a more appropriate spot, perhaps, could not have been selected for a conversation upon the progress of civilization, than the summit of vesuvius, from which, to adopt the language of _ambrosio_, "we see not only the power and activity of man as existing at present, and of which the highest example may be represented by the steam-boat departing from palermo, but we may likewise view scenes which carry us into the very bosom of antiquity, and as it were make us live with the generations of past ages." the author, who assumes throughout this dialogue the name of _philalethes_, after having been duly rallied by his friends on the subject of his vision, thus expresses himself:--"i will acknowledge that the vision in the colosæum is a fiction; but the most important parts of it really occurred to me in sleep, particularly that in which i seemed to leave the earth and launch into the infinity of space, under the guidance of a tutelary genius. and the origin and progress of civil society form likewise parts of another dream which i had many years ago; and it was in the reverie which happened when you quitted me in the colosæum, that i wove all these thoughts together, and gave them the form in which i narrated them to you.--i do not say that they are strictly to be considered as an accurate representation of my waking thoughts; for i am not quite convinced that dreams are always the representations of the state of the mind, modified by organic diseases or by associations. there are certainly no absolutely new ideas produced in sleep; yet i have had more than one instance, in the course of my life, of most extraordinary combinations occurring in this state, which have had considerable influence on my feelings, my imagination, and my health." _philalethes_ now relates a fact to which his preceding observation more immediately referred; he anticipates unbelief,--but he declares that he mentions nothing but a simple fact. "almost a quarter of a century ago, i contracted that terrible form of typhus fever known by the name of jail fever,--i may say, not from any imprudence of my own, but whilst engaged in putting in execution a plan for ventilating one of the great prisons of the metropolis.[ ] my illness was severe and dangerous; as long as the fever continued, my dreams and deliriums were most painful and oppressive; but when weakness consequent to exhaustion came on, and when the probability of death seemed to my physicians greater than that of life, there was an entire change in all my ideal combinations. i remained in an apparently senseless or lethargic state, but, in fact, my mind was peculiarly active; there was always before me the form of a beautiful woman, with whom i was engaged in the most interesting and intellectual conversation." [ ] see page , vol. i. for an account of this event. _ambrosio_ and _onuphrio_ very naturally suggest that this could have been no other than the image of some favourite maiden which had haunted his imagination; but _philalethes_ rejects with indignation such an explanation of the vision. "i will not," he exclaims, "allow you to treat me with ridicule on this point, till you have heard the second part of my tale. ten years after i had recovered from the fever, and when i had almost lost the recollection of the vision, it was recalled to my memory by a very blooming and graceful maiden fourteen or fifteen years old, that i accidentally met during my travels in illyria; but i cannot say that the impression made upon my mind by this female was very strong. now comes the extraordinary part of the narrative: ten years after,--twenty years after my first illness, at a time when i was exceedingly weak from a severe and dangerous malady, which for many years threatened my life, and when my mind was almost in a desponding state, being in a course of travels ordered by my medical advisers, i again met the person who was the representative of my visionary female; and to her kindness and care, i believe, i owe what remains to me of existence. my despondency gradually disappeared, and though my health still continued weak, life began to possess charms for me which i had thought were for ever gone; and i could not help identifying the living angel with the vision which appeared as my guardian genius during the illness of my youth." the reader will probably agree with _onuphrio_, in seeing in this history nothing beyond the influence of an imagination excited by disease. the discourse now turns upon that part of the vision in the colosæum in which was exhibited the early state of man, after his first creation, and which _ambrosio_ considers as not only incompatible with revelation, but likewise with reason and every thing that we know respecting the history or traditions of the early nations of antiquity. i shall merely state the objection which _ambrosio_ offers. i must then refer the reader to the work itself for an account of the discussion it provoked. "_ambrosio._--you consider man, in his early state, a savage like those who now inhabit new holland, or new zealand, acquiring, by the little use that they make of a feeble reason, the power of supporting and extending life. now, i contend that, if man had been so created, he must inevitably have been destroyed by the elements, or devoured by savage beasts, so infinitely his superiors in physical force." during the discussion, an opinion is advanced by _ambrosio_, so singular, that i must be allowed to quote it. "i consider," says he, "all the miraculous parts of our religion as effected by changes in the sensations or ideas of the human mind, and not by physical changes in the order of nature! to infinite wisdom and power, a change in the intellectual state of the human being may be the result of a momentary will, and the mere act of faith may produce the change. how great the powers of imagination are, even in ordinary life, is shown by many striking facts, and nothing seems impossible to this imagination when acted upon by divine influence." this is surely a most extraordinary line of argument for the apologist of the christian faith, and of the miracles by which it is supported. in the third dialogue, called the unknown, the author and his friends, _ambrosio_ and _onuphrio_, make an excursion to the remains of the temples of pæstum. "were my existence to be prolonged through ten centuries," exclaims the author, "i think i could never forget the pleasure i received on that delicious spot." in contemplating beautiful scenery, much of its interest depends upon the feelings and associations of the moment; and the author was upon this occasion evidently in that poetical frame of mind which sheds a magic light over every landscape, and converts the most ordinary objects into emblems of morality: in the admixture of the olive and the cypress tree, he saw a connection, to memorialize, as it were, how near each other are life and death, joy and sorrow; while the music of the birds, and, above all, the cooing of the turtle-doves, by overpowering the murmuring of the waves and the whistling of the winds, served but to show him that, in the strife of nature, the voice of love is predominant. with their hearts touched by the scene they had witnessed, the travellers descended to the ruins, and began to examine those wonderful remains which have outlived even the name of the people by whom they were raised. while engaged in measuring the doric columns in the interior of the temple of neptune, a stranger, remarkable both in dress and appearance, was observed to be writing in a memorandum book; the author immediately addresses him, and becoming mutually pleased with each other, they enter into a conversation of high scientific interest. the sentiments delivered by the "unknown," for by this title is the philosopher designated, notwithstanding their dramatic dress, are evidently to be received as the bequest of the latest scientific opinions of sir h. davy upon several important subjects, and must consequently command our respect and consideration. to a question relative to the nature of the masses of travertine, of which the ruins consisted, the unknown replied, that they were certainly produced by deposition from water; and he rather believed, that a lake in the immediate neighbourhood of the city furnished the quarry. the party are then described as visiting this spot. "there was something peculiarly melancholy in the character of this water; all the herbs around it were grey, as if incrusted with marble; a few buffaloes were slaking their thirst in it, which ran wildly away at our approach, and appeared to retire into a rocky excavation or quarry at the end of the lake. 'there,' said the stranger, 'is what i believe to be the source of those large and durable stones which you see in the plain before you. this water rapidly deposits calcareous matter, and even, if you throw a stick into it, a few hours is sufficient to give it a coating of this substance. whichever way you turn your eyes, you see masses of this recently produced marble, the consequence of the overflowing of the lake during the winter floods.' * * * * * "this water is like many, i may say most, of the sources which rise at the foot of the apennines; it holds carbonic acid in solution, which has dissolved a portion of the calcareous matter of the rock through which it has passed:--this carbonic acid is dissipated in the atmosphere, and the marble, slowly thrown down, assumes a crystalline form, and produces coherent stones. the lake before us is not particularly rich in the quantity of calcareous matter, for, as i have found by experience, a pint of it does not afford more than five or six grains; but the quantity of fluid and the length of time are sufficient to account for the immense quantities of tufa and rock which, in the course of ages, have accumulated in this situation. * * * * * "it can, i think, be scarcely doubted that there is a source of volcanic fire at no great distance from the surface, in the whole of southern italy; and, this fire acting upon the calcareous rocks of which the apennines are composed, must constantly detach from them carbonic acid, which rising to the sources of the springs, deposited from the waters of the atmosphere, must give them their impregnation, and enable them to dissolve calcareous matter. i need not dwell upon Ætna, vesuvius, or the lipari islands, to prove that volcanic fires are still in existence; and there can be no doubt that, in earlier periods, almost the whole of italy was ravaged by them; even rome itself, the eternal city, rests upon the craters of extinct volcanoes; and i imagine that the traditional and fabulous record of the destruction made by the conflagration of phaeton, in the chariot of the sun, and his falling into the po, had reference to a great and tremendous igneous volcanic eruption which extended over italy, and ceased only near the po, at the foot of the alps. be this as it may, the sources of carbonic acid are numerous, not merely in the neapolitan but likewise in the roman and tuscan states. the most magnificent waterfall in europe, that of the velino near terni, is partly fed by a stream containing calcareous matter dissolved by carbonic acid, and it deposits marble, which crystallizes even in the midst of its thundering descent and foam, in the bed in which it falls. "there is a lake in latium, a few yards above the lacus albula, where the ancient romans erected their baths, which sends down a considerable stream of tepid water to the larger lake; but this water is less strongly impregnated with carbonic acid; the largest lake is actually a saturated solution of this gas, which escapes from it in such quantities in some parts of its surface, that it has the appearance of being actually in ebullition. its temperature i ascertained to be, in the winter, in the warmest parts, above degrees of fahrenheit, and as it appears to be pretty constant, it must be supplied with heat from a subterraneous source, being nearly twenty degrees above the mean temperature of the atmosphere. kircher has detailed, in his _mundus subterraneus_, various wonders respecting this lake, most of which are unfounded; such as, that it is unfathomable,--that it has at the bottom the heat of boiling water, and that floating islands rise from the gulf which emits it. it must certainly be very difficult, or even impossible, to fathom a source which rises with so much violence from a subterraneous excavation; and at a time when chemistry had made small progress, it was easy to mistake the disengagement of carbonic acid for an actual ebullition. the floating islands are real; but neither the jesuit, nor any of the writers who have since described this lake, had a correct idea of their origin, which is exceedingly curious. the high temperature of this water, and the quantity of carbonic acid that it contains, render it peculiarly fitted to afford a pabulum or nourishment to vegetable life; the banks of travertine are every where covered with reeds, lichens, confervæ, and various kinds of aquatic vegetables; and at the same time that the process of vegetable life is going on, the crystallizations of the calcareous matter, which is every where deposited in consequence of the escape of carbonic acid, likewise proceed, giving a constant milkiness to what from its tint would otherwise be a blue fluid. so rapid is the vegetation, owing to the decomposition of the carbonic acid, that even in winter, masses of confervæ and lichens, mixed with deposited travertine, are constantly detached by the current of water from the bank, and float down the stream, which being a considerable river, is never without many of these small islands on its surface; they are sometimes only a few inches in size, and composed merely of dark green confervæ, or purple or yellow lichens; but they are sometimes even of some feet in diameter, and contain seeds and various species of common water-plants, which are usually more or less incrusted with marble. there is, i believe, no place in the world where there is a more striking example of the opposition or contrast of the laws of animate and inanimate nature, of the forces of inorganic chemical affinity and those of the powers of life. vegetables, in such a temperature, and every where surrounded by food, are produced with a wonderful rapidity; but the crystallizations are formed with equal quickness, and they are no sooner produced than they are destroyed together. the quantity of vegetable matter and its heat make it the resort of an infinite variety of insect tribes; and, even in the coldest days in winter, numbers of flies may be observed on the vegetables surrounding its banks or on its floating islands, and a quantity of their larvæ may be seen there, sometimes incrusted and entirely destroyed by calcareous matter, which is likewise often the fate of the insects themselves, as well as of various species of shell-fish that are found amongst the vegetables which grow and are destroyed in the travertine on its banks. * * * * * "i have passed many hours, i may say, many days, in studying the phenomena of this wonderful lake; it has brought many trains of thought into my mind connected with the early changes of our globe, and i have sometimes reasoned from the forms of plants and animals preserved in marble in this warm source, to the grander depositions in the secondary rocks, where the zoophytes or coral insects have worked upon a grand scale, and where palms and vegetables now unknown are preserved with the remains of crocodiles, turtles, and gigantic extinct animals of the _sauri_ genus, and which appear to have belonged to a period when the whole globe possessed a much higher temperature. * * * * * "then, from all we know, this lake, except in some change in its dimensions, continues nearly in the same state in which it was described seventeen hundred years ago by pliny, and i have no doubt contains the same kinds of floating islands, the same plants, and the same insects. during the fifteen years that i have known it, it has appeared precisely identical in these respects; and yet it has the character of an accidental phenomenon depending upon subterraneous fire. how marvellous then are those laws by which even the humblest types of organic existence are preserved, though born amidst the sources of their destruction, and by which a species of immortality is given to generations, floating, as it were, like evanescent bubbles on a stream raised from the deepest caverns of the earth, and instantly losing what may be called its spirit in the atmosphere!" from this interesting discourse on the formation of travertine, the conversation naturally turned to geology; and i shall here again be compelled to give another copious extract, in order to show what were the latest opinions of sir h. davy upon this subject. if any doubt could exist as to the views here given being those entertained by the author, it is at once removed by his letter to mr. poole, in which, alluding to the work under review, he says, "_it contains the essence of my philosophical opinions._" "on the geological scheme of the early history of the globe, there are only analogies to guide us, which different minds may apply and interpret in different ways; but i will not trifle with a long preliminary discourse. astronomical deductions and actual measures by triangulation prove that the globe is an oblate spheroid flattened at the poles; and this form, we know, by strict mathematical demonstrations, is precisely the one which a fluid body revolving round its axis and become solid at its surface by the slow dissipation of its heat or other causes, would assume. i suppose, therefore, that the globe, in the first state in which the imagination can venture to consider it, was a fluid mass with an immense atmosphere, revolving in space round the sun, and that by its cooling, a portion of its atmosphere was condensed in water which occupied a part of the surface. in this state, no forms of life, such as now belong to our system, could have inhabited it; and i suppose the crystalline rocks, or, as they are called by geologists, the _primary_ rocks, which contain no vestiges of a former order of things, were the results of the first consolidation on its surface. upon the farther cooling, the water which more or less had covered it, contracted; depositions took place, shell-fish, and coral insects of the first creation began their labours, and islands appeared in the midst of the ocean, raised from the deep by the productive energies of millions of zoophytes. these islands became covered with vegetables fitted to bear a high temperature, such as palms, and various species of plants similar to those which now exist in the hottest part of the world. and the submarine rocks or shores of these new formations of land became covered with aquatic vegetables, on which various species of shell-fish and common fishes found their nourishment. the fluids of the globe in cooling deposited a large quantity of the materials they held in solution, and these deposits agglutinating together the sand, the immense masses of coral rocks, and some of the remains of the shells and fishes found round the shores of the primitive lands, produced the first order of _secondary_ rocks. "as the temperature of the globe became lower, species of the oviparous reptiles were created to inhabit it; and the turtle, crocodile, and various gigantic animals of the _sauri_ kind, seem to have haunted the bays and waters of the primitive lands. but in this state of things there was no order of events similar to the present,--the crust of the globe was exceedingly slender, and the source of fire a small distance from the surface. in consequence of contraction in one part of the mass, cavities were opened, which caused the entrance of water, and immense volcanic explosions took place, raising one part of the surface, depressing another, producing mountains and causing new and extensive depositions from the primitive ocean. changes of this kind must have been extremely frequent in the early epochas of nature; and the only living forms of which the remains are found in the strata that are the monuments of these changes, are those of plants, fishes, birds, and oviparous reptiles, which seem most fitted to exist in such a war of the elements. "when these revolutions became less frequent, and the globe became still more cooled, and the inequalities of its temperature preserved by the mountain chains, more perfect animals became its inhabitants, many of which, such as the mammoth, megalonix, megatherium, and gigantic hyena, are now extinct. at this period, the temperature of the ocean seems to have been not much higher than it is at present, and the changes produced by occasional eruptions of it have left no consolidated rocks. yet one of these eruptions appears to have been of great extent and of some duration, and seems to have been the cause of those immense quantities of water-worn stones, gravel, and sand, which are usually called _diluvian_ remains;--and it is probable that this effect was connected with the elevation of a new continent in the southern hemisphere by volcanic fire. when the system of things became so permanent, that the tremendous revolutions depending upon the destruction of the equilibrium between the heating and cooling agencies were no longer to be dreaded, the creation of man took place; and since that period there has been little alteration in the physical circumstances of our globe. volcanoes sometimes occasion the rise of new islands, portions of the old continents are constantly washed by rivers into the sea, but these changes are too insignificant to affect the destinies of man, or the nature of the physical circumstances of things. on the hypothesis that i have adopted, however, it must be remembered, that the present surface of the globe is merely a thin crust surrounding a nucleus of fluid ignited matter; and consequently, we can hardly be considered as actually safe from the danger of a catastrophe by fire. * * * * * "i beg you to consider the views i have been developing as merely hypothetical, one of the many resting-places that may be taken by the imagination in considering this subject. there are, however, distinct facts in favour of the idea, that the interior of the globe has a higher temperature than the surface; the heat increasing in mines the deeper we penetrate, and the number of warm sources which rise from great depths, in almost all countries, are certainly favourable to the idea. the opinion, that volcanoes are owing to this general and simple cause, is, i think, likewise more agreeable to the analogies of things, than to suppose them dependent upon partial chemical changes, such as the action of air and water upon the combustible bases of the earths and alkalies, though it is extremely probable that these substances may exist beneath the surface, and may occasion some results of volcanic fire;--and on this subject my notion may perhaps be the more trusted, as for a long while i thought volcanic eruptions were owing to chemical agencies of the newly discovered metals of the earths and alkalies, and i made many and some dangerous experiments in the hope of confirming this notion, but in vain. * * * * * "i have no objection to the '_refined plutonic view_,' (of professor playfair and sir james hall,) as capable of explaining many existing phenomena; indeed, you must be aware that i have myself had recourse to it. what i contend against is, its application to explain the formations of the secondary rocks, which i think clearly belong to an order of facts not at all embraced by it. in the plutonic system, there is one simple and constant order assumed, which may be supposed eternal. the surface is constantly imagined to be disintegrated, destroyed, degraded, and washed into the bosom of the ocean by water, and as constantly consolidated, elevated, and regenerated by fire; and the ruins of the old form the foundations of the new world. it is supposed that there are always the same types both of dead and living matter,--that the remains of rocks, of vegetables, and animals of one age are found imbedded in rocks raised from the bottom of the ocean in another. now, to support this view, not only the remains of living beings which at present people the globe, might be expected to be found in the oldest secondary strata, but even those of the art of man, the most powerful and populous of its inhabitants, which is well known not to be the case. on the contrary, each stratum of the secondary rocks contains remains of peculiar and mostly now unknown species of vegetables and animals. in those strata which are deepest, and which must consequently be supposed to be the earliest deposited, forms even of vegetable life are rare; shells and vegetable remains are found in the next order; the bones of fishes and oviparous reptiles exist in the following class; the remains of birds, with those of the same genera mentioned before, in the next order; those of quadrupeds of extinct species in a still more recent class; and it is only in the loose and slightly consolidated strata of gravel and sand, and which are usually called diluvian formations, that the remains of animals, such as now people the globe, are found, with others belonging to extinct species. but in none of these formations, whether called secondary, tertial, or diluvial, have the remains of man, or any of his works, been discovered. it is, i think, impossible to consider the organic remains found in any of the earlier secondary strata, the lias-limestone and its congenerous formations, for instance, without being convinced, that the beings whose organs they formed belonged to an order of things entirely different from the present. gigantic vegetables, more nearly allied to the palms of the equatorial countries than to any other plants, can only be imagined to have lived in a very high temperature; and the immense reptiles, the _megalosauri_, with paddles instead of legs, and clothed in mail, in size equal, or even superior to the whale; and the great amphibia _plethiosauri_, with bodies like turtles, but furnished with necks longer than their bodies, probably to enable them to feed on vegetables growing in the shallows of the primitive ocean, seem to show a state in which low lands, or extensive shores, rose above an immense calm sea, and when there were no great mountain chains to produce inequalities of temperature, tempests, or storms. were the surface of the earth now to be carried down into the depths of the ocean, or were some great revolution of the waters to cover the existing land, and it was again to be elevated by fire, covered with consolidated depositions of sand or mud, how entirely different would it be in its characters from any of the secondary strata! its great features would undoubtedly be the works of man: hewn stones, and statues of bronze and marble, and tools of iron, and human remains, would be more common than those of animals, on the greatest part of the surface; the columns of pæstum, or of agrigentum, or the immense iron bridges of the thames, would offer a striking contrast to the bones of the crocodiles, or _sauri_, in the older rocks, or even to those of the mammoth, or _elephas primogenius_, in the diluvial strata. and whoever dwells upon this subject must be convinced, that the present order of things, and the comparatively recent existence of man, as the master of the globe, is as certain as the destruction of a former and a different order, and the extinction of a number of living forms, which have now no types in being, and which have left their remains wonderful monuments of the revolutions of nature." the fourth dialogue, to which is given the title of "the proteus, or immortality," is of a more desultory nature than those which precede it. it contains many beautiful descriptions of scenery in the alpine country of austria; furnishes an interesting account of that most singular reptile the _proteus anguinus_, which is found only in the limestone caverns of carniola, and concludes with reflections upon the indestructibility of the sentient principle. the author's companion, during the tour he describes, is a scientific friend, whom he calls _eubathes_. the dialogue opens with a passage of considerable pathos and eloquence: the author having been recalled to england by a melancholy event, the death of a very near and dear relation, describes his feelings on entering london. "in my youth, and through the prime of manhood, i never entered london without feelings of pleasure and hope. it was to me as the grand theatre of intellectual activity, the field of every species of enterprise and exertion, the metropolis of the world of business, thought, and action. there, i was sure to find the friends and companions of my youth, to hear the voice of encouragement and praise. there, society of the most refined kind offered daily its banquets to the mind, with such variety that satiety had no place in them, and new objects of interest and ambition were constantly exciting attention either in politics, literature, or science. "i now entered this great city in a very different tone of mind--one of settled melancholy, not merely produced by the mournful event which recalled me to my country, but owing likewise to an entire change in the condition of my physical, moral, and intellectual being. my health was gone, my ambition was satisfied; i was no longer excited by the desire of distinction; what i regarded most tenderly was in the grave; and to take a metaphor, derived from the change produced by time in the juice of the grape, my cup of life was no longer sparkling, sweet, and effervescent; it had lost its sweetness without losing its power, and it had become bitter." there is perhaps not a more splendid passage to be found in the work; and it is scarcely inferior to dr. johnson's memorable conclusion to the preface of his dictionary. "after passing a few months in england," says he, "and enjoying (as much as i could enjoy any thing) the society of the few friends who still remained alive, the desire of travel again seized me. i had preserved amidst the wreck of time, one feeling strong and unbroken--the love of natural scenery; and this, in advanced life, formed a principal motive for my plans of conduct and action." the fall of the traun, about ten miles below gmünden, was one of his favourite haunts; and he describes an accident of the most awful description which befell him at this place. while amusing himself on the water by a rapid species of locomotion, in a boat so secured by a rope as to allow only of a limited range, the tackle gave way, and he was rapidly precipitated down the cataract. he remained for some time after his rescue in a state of insensibility, and on recovering found himself attended by his mysterious friend the "unknown," who had so charmed him in his excursion to pæstum. with this stranger, he proceeded on his tour; and he again becomes the medium through which much philosophical information is conveyed to the reader. they visit together the grotto of the maddalena at adelsberg, and he gives us the conversation that took place in that extraordinary cavern. "_philalethes._--if the awful chasms of dark masses of rock surrounding us appear like the work of demons, who might be imagined to have risen from the centre of the earth, the beautiful works of nature above our heads may be compared to a scenic representation of a temple or banquet-hall for fairies or genii, such as those fabled in the arabian romances. "_the unknown._--a poet might certainly place here the palace of the king of the gnomes, and might find marks of his creative power in the small lake close by, on which the flame of the torch is now falling; for, there it is that i expect to find the extraordinary animals which have been so long the objects of my attention. "_eubathes._--i see three or four creatures, like slender fish, moving on the mud below the water. "_the unknown._--i see them; they are the protei,--now i have them in my fishing-net, and now they are safe in the pitcher of water. at first view, you might suppose this animal to be a lizard, but it has the motions of a fish. its head, and the lower part of its body and its tail, bear a strong resemblance to those of the eel; but it has no fins; and its curious bronchial organs are not like the gills of fishes; they form a singular vascular structure, as you see, almost like a crest, round the throat, which may be removed without occasioning the death of the animal, who is likewise furnished with lungs. with this double apparatus for supplying air to the blood, it can live either below or above the surface of the water. its fore-feet resemble hands, but they have only three claws or fingers, are too feeble to be of use in grasping, or supporting the weight of the animal; the hinder feet have only two claws or toes, and in larger specimens are found so imperfect as to be almost obliterated. it has small points in place of eyes, as if to preserve the analogy of nature. its nasal organs appear large; and it is abundantly furnished with teeth, from which it may be concluded that it is an animal of prey; yet in its confined state it has never been known to eat, and it has been kept alive for many years by occasionally changing the water in which it is placed. "_eubathes._--is this the only place in carniola where these animals are found? "_the unknown._--they were first discovered here by the late baron zois; but they have since been found, though rarely, at sittich, about thirty miles distant, thrown up by water from a subterraneous cavity; and i have lately heard it reported that some individuals of the same species have been recognised in the calcareous strata in sicily. i think it cannot be doubted, that their natural residence is an extensive deep subterranean lake, from which in great floods they sometimes are forced through the crevices of the rocks into this place where they are found; and it does not appear to me impossible, when the peculiar nature of the country in which we are is considered, that the same great cavity may furnish the individuals which have been found at adelsberg and at sittich. * * * * * "this adds one more instance to the number already known of the wonderful manner in which life is produced and perpetuated in every part of our globe, even in places which seem the least suited to organized existence. and the same infinite power and wisdom which has fitted the camel and the ostrich for the deserts of africa, the swallow that secretes its own nest for the caves of java, the whale for the polar seas, and the morse and white bear for the arctic ice, has given the proteus to the deep and dark subterraneous lakes of illyria,--an animal to whom the presence of light is not essential, and who can live indifferently in air and in water, on the surface of the rock, or in the depths of the mud." much interesting physiological discussion follows. i shall, however, merely notice the opinion delivered by the "unknown," on the subject of respiration, and which i think shows that, at the conclusion of his career, davy entertained the same notions, with regard to the communication of some ethereal principle to the blood, as he maintained in the earlier part of his life.[ ]--"the obvious chemical alteration of the air is sufficiently simple in this process; a certain quantity of carbon only is added to it, and it receives an addition of heat or vapour; the volumes of elastic fluid inspired and expired (making allowance for change of temperature,) are the same, and if ponderable agents only were to be regarded, it would appear as if the only use of respiration were to free the blood from a certain quantity of carbonaceous matter. but it is probable that this is only a secondary object, and that the change produced by respiration upon the blood is of a much more important kind. oxygen, in its elastic state, has properties which are very characteristic; it gives out light by compression, which is not certainly known to be the case with any other elastic fluid except those which oxygen has entered without undergoing combustion; and from the fire it produces in certain processes, and from the manner in which it is separated by positive electricity in the gaseous state from its combinations, it is not easy to avoid the supposition, that it contains, besides its ponderable elements, some very subtile matter which is capable of assuming the form of heat and light. _my idea_ is, that the common air inspired enters into the venous blood entire, in a state of dissolution, carrying with it its subtile or ethereal part, which in ordinary cases of chemical change is given off; that it expels from the blood carbonic acid gas and azote; and that, in the course of the circulation, its ethereal part and its ponderable part undergo changes which belong to laws that cannot be considered as chemical,--the ethereal part probably producing animal heat and other effects, and the ponderable part contributing to form carbonic acid and other products. the arterial blood is necessary to all the functions of life, and it is no less connected with the irritability of the muscles and the sensibility of the nerves than with the performance of all the secretions." [ ] see vol. i. page . the fifth dialogue is entitled "the chemist." its object is to demonstrate the importance of this noble science. an interlocutor is made to disparage its utility, and to mark its weaker points. these of course are answered, the sceptic becomes a true believer, and the intellectual gladiators separate mutually satisfied with each other. "_eubathes._--i feel disposed to join you in attacking this favourite study of our friend, _but merely_ to provoke him to defend it, in order to call forth his skill and awaken his eloquence. "_the unknown._--i have no objection. let there be a fair discussion: remember, we fight only with foils, and the point of mine shall be covered with velvet." after having enumerated the scientific attainments necessary to constitute the chemist, and described the apparatus essential for understanding what has been already done in the science, he proceeds to define the intellectual qualities which he considers necessary for discovery, or for the advancement of the science. amongst them, patience, industry, and neatness in manipulation, and accuracy and minuteness in observing and registering the phenomena which occur, are essential. a steady hand and a quick eye are most useful auxiliaries; but there have been very few great chemists who have preserved these advantages through life; for the business of the laboratory is often a service of danger, and the elements, like the refractory spirits of romance, though the obedient slaves of the magician, yet sometimes escape the influence of his talisman, and endanger his person. both the hands and eyes of others, however, may be sometimes advantageously made use of. by often repeating a process or an observation, the errors connected with hasty operations or imperfect views are annihilated; and, provided the assistant has no preconceived notions of his own, and is ignorant of the object of his employer in making the experiment, his simple and bare detail of facts will often be the best foundation for an opinion. with respect to the higher qualities of intellect necessary for understanding and developing the general laws of the science, the same talents, i believe, are required as for making advancement in every other department of human knowledge; i need not be very minute. the imagination must be active and brilliant in seeking analogies; yet entirely under the influence of the judgment in applying them. the memory must be extensive and profound; rather, however, calling up general views of things than minute trains of thought;--the mind must not be like an encyclopedia,--a burthen of knowledge, but rather a critical dictionary, which abounds in generalities, and points out where more minute information may be obtained. * * * * * "in announcing even the greatest and most important discoveries, the true philosopher will communicate his details with modesty and reserve; he will rather be a useful servant of the public, bringing forth a light from under his cloak when it is needed in darkness, than a charlatan exhibiting fire-works, and having a trumpeter to announce their magnificence. "i see you are smiling, and think what i am saying in bad taste; yet, notwithstanding, i will provoke your smiles still farther, by saying a word or two on his other moral qualities. that he should be humble-minded, you will readily allow, and a diligent searcher after truth, and neither diverted from this great object by the love of transient glory or temporary popularity, looking rather to the opinion of ages than to that of a day, and seeking to be remembered and named rather in the epochas of historians than in the columns of newspaper writers or journalists. he should resemble the modern geometricians in the greatness of his views and the profoundness of his researches, and the ancient alchemists in industry and piety. i do not mean that he should affix written prayers and inscriptions[ ] of recommendations of his processes to providence, as was the custom of peter wolfe, who was alive in my early days; but his mind should always be awake to devotional feelings; and in contemplating the variety and the beauty of the external world, and developing its scientific wonders, he will always refer to that infinite wisdom, through whose beneficence he is permitted to enjoy knowledge; and, in becoming wiser, he will become better,--he will rise at once in the scale of intellectual and moral existence, his increased sagacity will be subservient to a more exalted faith, and in proportion as the veil becomes thinner through which he sees the causes of things, he will admire more the brightness of the divine light by which they are rendered visible." [ ] in illustration of the pious custom here alluded to by sir h. davy, it may be observed, that the vessels of the alchemists very commonly bore some emblem; such, for instance, as that of the cross; and from which, indeed, the word _crucible_ derived its appellation. the sixth and last dialogue, entitled "pola, or time," presents a series of reflections, to which a view of the decaying amphitheatre at pola, an ancient town in the peninsula of istria, is represented as having given origin. on former occasions, the inspection of the mouldering works of past ages called up trains of thought rather of a moral than of a physical character; in the present dialogue, the effects of time are considered in their relations to the mechanical and chemical laws by which material forms are destroyed, or rather changed,--for the author has shown by a number of beautiful examples, that without decay there can be no reproduction, and that the principle of change is a principle of life. having considered the influence of gravitation, the chemical and mechanical agencies of water, air, and electricity, and the energies of organized beings, in producing those diversified phenomena which, in our metaphysical abstractions, we universally refer to time, he proceeds to enquire how far art can counteract their operation. a great philosopher, he observes, has said, "man can in no other way command nature but in obeying her laws:" it is evident that, by the application of some of those principles which she herself employs, we may for a while arrest the progress of changes which are ultimately inevitable. "yet, when all is done that can be done in the work of conservation, it is only producing a difference in the degree of duration. it is evident that none of the works of a mortal can be eternal, as none of the combinations of a limited intellect can be infinite. the operations of nature, when slow, are no less sure; however man may, for a time, usurp dominion over her, she is certain of recovering her empire. he converts her rocks, her stones, her trees, into forms of palaces, houses, and ships; he employs the metals found in the bosom of the earth, as instruments of power, and the sands and clays which constitute its surface, as ornaments and resources of luxury; he imprisons air by water, and tortures water by fire to change, or modify, or destroy the natural forms of things. but in some lustrums his works begin to change, and in a few centuries they decay and are in ruins; and his mighty temples, framed as it were for immortal and divine purposes, and his bridges formed of granite and ribbed with iron, and his walls for defence, and the splendid monuments by which he has endeavoured to give eternity even to his perishable remains, are gradually destroyed; and these structures, which have resisted the waves of the ocean, the tempests of the sky, and the stroke of the lightning, shall yield to the operation of the dews of heaven,--of frost, rain, vapour, and imperceptible atmospheric influences; and as the worm devours the lineaments of his mortal beauty, so the lichens and the moss and the most insignificant plants shall feed upon his columns and his pyramids, and the most humble and insignificant insect shall undermine and sap the foundations of his colossal works, and make their habitations amongst the ruins of his palaces and the falling seats of his earthly glory." on no occasion can such a subject be presented to a contemplative mind, without filling it with awe and wonder; but the circumstances under which these reflections are presented to us, in the last days of our philosopher, impress upon them an almost oracular solemnity. when we remember that while the mind of the philosopher was thus engaged in identifying the processes of decay with those of renovation in the system of nature, his body was palsied, and the current of his life fast ebbing, we cannot but admire that active intelligence which sparkled with such undiminished lustre amidst the wreck of its earthly tenement. in the extracts which have been introduced from this last work, i trust the pledge that was given in the earlier part of these memoirs, has been redeemed by showing that a powerful imagination is not necessarily incompatible with a sound judgment, that the flowers of fancy are not always blighted by the cold realities of science, but that the poet and philosopher may, under the auspices of a happy genius, mutually assist each other in expounding the mysteries of nature. it cannot be denied, as a general aphorism, that the tree which expands its force in flowers is generally deficient in fruit; but the mind of davy, to borrow one of his own metaphors, may be likened to those fabled of the hesperides, which produced at once buds, leaves, blossoms, and fruits. the happy effects resulting from this rare and nicely adjusted combination of talents, offer themselves as interesting subjects of biographical contemplation, and they can be studied only with success by a comparative analysis of different minds. that the superiority of davy greatly depended upon the vivacity and compass of his imagination cannot be doubted, and such an opinion was well expressed by mr. davies gilbert, in his late address to the society:--"the poetic bent of davy's mind seems never to have left him. to that circumstance i would ascribe the distinguishing features in his character and in his discoveries:--a vivid imagination sketching out new tracks in regions unexplored, for the judgment to select those leading to the recesses of abstract truth." i have always thought that the mind of the late dr. clarke, the mineralogical professor of cambridge, was little less imaginative than that of davy; but it was deficient in judgment, and therefore often conducted him to error instead of to truth. dr. black was not deficient in imagination, and certainly not in judgment; but there was a constitutional apathy, arising probably from ill health, which damped his noblest efforts.[ ] [ ] in addition to the anecdote already related of him, the following may serve to give a still greater force to this opinion. soon after the appearance of mr. cavendish's paper on hydrogen gas, in which he made an approximation to the specific gravity of that body, showing that it was at least ten times lighter than common air, dr. black invited a party of his friends to supper, informing them that he had a curiosity to show them. dr. hutton and several others assembled, when, having the allentois of a calf filled with hydrogen gas, upon setting it at liberty, it immediately ascended, and adhered to the ceiling. the phenomenon was easily accounted for: it was taken for granted that a small black thread had been attached to the allentois,--that this thread passed through the ceiling, and that some one in the apartment above, by pulling the thread, elevated it to the ceiling, and kept it in that position. this explanation was so probable, that it was acceded to by the whole company; though, like many other plausible theories, it was not true; for when the allentois was brought down, no thread whatever was found attached to it. dr. black explained the cause of the ascent to his admiring friends; but such was his unaccountable apathy, that he never gave the least account of this curious experiment even to his class; and more than twelve years elapsed before this obvious property of hydrogen gas was applied to the elevation of air balloons, by m. charles, in paris. i am indebted for this anecdote to the "history of chemistry," a very able work by dr. thomson, constituting the third number of the national library. it is by the rarity with which the talent of seizing upon remote analogies is associated with a spirit of patient and subtile investigation of details, and a quick perception of their value, that the fact so truly stated by mr. babbage is to be explained; _viz._ that long intervals frequently elapse between the discovery of new principles in science and their practical application: thus he observes, that "the principle of the hydrostatic paradox was known as a speculative truth in the time of stevinus, as far back as the year ,--and its application to raising heavy weights has long been stated in elementary treatises on natural philosophy, as well as constantly exhibited in lectures; yet it may fairly be regarded as a mere abstract principle, until the late mr. bramah, by substituting a pump, instead of the smaller column, converted it into a most valuable and powerful engine. the principle of the convertibility of the centres of oscillation and suspension in the pendulum, discovered by huygens more than a century and a half ago, remained, until within these few years, a sterile though most elegant proposition; when, after being hinted at by prony, and distinctly pointed out by bonenberger, it was employed by captain kater as the foundation of a most convenient method of determining the length of the pendulum. the interval which separated the discovery of dr. black, of latent heat, from the beautiful and successful application of it to the steam-engine, was comparatively short; but it required the efforts of two minds; and both were of the highest order."[ ] [ ] "reflections on the decline of science in england," page . the discoveries of davy present themselves in striking contrast with such instances. the same powerful genius that developed the laws of electro-chemical decomposition, was the first to apply them for the purpose of obviating metallic corrosion; and the nature of _fire-damp_, and the fact of its combustion being arrested in its passage through capillary tubes, were alike the discoveries of him who first applied them for the construction of a safety-lamp.[ ] [ ] while upon this subject, it is impossible not to notice the discoveries of dr. franklin, who combined in a remarkable degree a fertile imagination with a solid judgment; and the fruit of this union is to be seen in the invention of conductors for the security of ships and buildings against the effects of lightning. the philosopher who, predicating the identity of lightning and electricity, conceived the bold and grand idea of drawing it down from the thunder-cloud, an experiment which in another age would have consigned him to the dungeon for impiety, or to the stake for witchcraft, himself applied this wonderful discovery to the preservation of buildings, by the invention of pointed rods of iron. of this invention it may be truly said, that he beat nature with her own weapons, and triumphed over her power by an obedience to her own laws. in contrasting the genius of wollaston with that of davy, let me not be supposed to invite a comparison to the disparagement of either, but rather to the glory of both, for by mutual reflection each will glow the brighter. if the animating principle of davy's mind was a powerful imagination, generalizing phenomena, and casting them into new combinations, so may the striking characteristic of wollaston's genius be said to have been an almost superhuman perception of minute detail. davy was ever imagining something greater than he knew; wollaston always knew something more than he acknowledged:--in wollaston, the predominant principle was to avoid error; in davy, it was the desire to discover truth. the tendency of davy, on all occasions, was to raise probabilities into facts; while wollaston as continually made them subservient to the expression of doubt. wollaston was deficient in imagination, and under no circumstances could he have become a poet; nor was it to be expected that his investigations should have led him to any of those comprehensive generalizations which create new systems of philosophy. he well knew the compass of his powers, and he pursued the only method by which they could be rendered available in advancing knowledge. he was a giant in strength, but it was the strength of antæus, mighty only on the earth. the extreme caution and reserve of his manner were inseparably connected with the habits of his mind; they pervaded every part of his character; in his amusements and in his scientific experiments, he displayed the same nice and punctilious observation,--whether he was angling for trout,[ ] or testing for elements, [ ] sir humphry davy has told us an anecdote which well illustrates this observation, while it affords a gratifying testimony of the kind feeling he entertained towards a kindred philosopher.--"there was--alas! that i must say _there was!_--an illustrious philosopher, who was nearly of the age of fifty before he made angling a pursuit, yet he became a distinguished fly-fisher, and the amusement occupied many of his leisure hours, during the last twelve years of his life. he indeed applied his preeminent acuteness, his science, and his philosophy, to aid the resources and exalt the pleasures of this amusement. i remember to have seen dr. wollaston, a few days after he had become a fly-fisher, carrying at his button-hole a piece of indian rubber, when by passing his silkworm link through a fissure in the middle, he rendered it straight, and fit for immediate use. many other anglers will remember other ingenious devices of my admirable and ever-to-be-lamented friend."--_salmonia. additional note_, edit. . he alike relied for success upon his subtile discrimination of minute circumstances. by comparing the writings as well as the discoveries of these two great philosophers, we shall readily perceive the intellectual distinctions i have endeavoured to establish. "from their fruits shall ye know them." the discoveries of davy were the results of extensive views and new analogies; those of wollaston were derived from a more exact examination of minute and, to ordinary observers, scarcely appreciable differences. this is happily illustrated by a comparison of the means by which each discovered new metals. the alkaline bases were the products of a comprehensive investigation, which had developed a new order of principles; the detection of palladium and rhodium among the ores of platinum, was the reward of delicate manipulation, and microscopic scrutiny. as chemical operators, i have already pointed out their striking peculiarities, and they will be found to be in strict keeping with the other features of their respective characters. i might extend the parallel farther; but dr. henry, in the eleventh edition of his "system of chemistry," has delineated the intellectual portraits of these two philosophers with so masterly a hand, that by quoting the passage, all farther observation will be rendered unnecessary. "to those high gifts of nature, which are the characteristics of genius, and which constitute its very essence, both those eminent men united an unwearied industry and zeal in research, and habits of accurate reasoning, without which even the energies of genius are inadequate to the achievement of great scientific designs. with these excellencies, common to both, they were nevertheless distinguishable by marked intellectual peculiarities. bold, ardent, and enthusiastic, davy soared to greater heights; he commanded a wider horizon; and his keen vision penetrated to its utmost boundaries. his imagination, in the highest degree fertile and inventive, took a rapid and extensive range in pursuit of conjectural analogies, which he submitted to close and patient comparison with known facts, and tried by an appeal to ingenious and conclusive experiments. he was imbued with the spirit, and was a master in the practice, of the inductive logic; and he has left us some of the noblest examples of the efficacy of that great instrument of human reason in the discovery of truth. he applied it, not only to connect classes of facts of more limited extent and importance, but to develope great and comprehensive laws, which embrace phenomena that are almost universal to the natural world. in explaining those laws, he cast upon them the illumination of his own clear and vivid conceptions;--he felt an intense admiration of the beauty, order, and harmony, which are conspicuous in the perfect chemistry of nature;--and he expressed those feelings with a force of eloquence which could issue only from a mind of the highest powers and of the finest sensibilities. with much less enthusiasm from temperament, dr. wollaston was endowed with bodily senses[ ] of extraordinary acuteness and accuracy, and with great general vigour of understanding. trained in the discipline of the exact sciences, he had acquired a powerful command over his attention, and had habituated himself to the most rigid correctness, both of thought and of language. he was sufficiently provided with the resources of the mathematics, to be enabled to pursue with success profound enquiries in mechanical and optical philosophy, the results of which enabled him to unfold the causes of phenomena not before understood, and to enrich the arts connected with those sciences, by the invention of ingenious and valuable instruments. in chemistry, he was distinguished by the extreme nicety and delicacy of his observations; by the quickness and precision with which he marked resemblances and discriminated differences; the sagacity with which he devised experiments and anticipated their results; and the skill with which he executed the analysis of fragments of new substances, often so minute as to be scarcely perceptible by ordinary eyes. he was remarkable, too, for the caution with which he advanced from facts to general conclusions: a caution which, if it sometimes prevented him from reaching at once to the most sublime truths, yet rendered every step of his ascent a secure station, from which it was easy to rise to higher and more enlarged inductions. thus these illustrious men, though differing essentially in their natural powers and acquired habits, and moving, independently of each other, in different paths, contributed to accomplish the same great ends--the evolving new elements; the combining matter into new forms; the increase of human happiness by the improvement of the arts of civilized life; and the establishment of general laws, that will serve to guide other philosophers onwards, through vast and unexplored regions of scientific discovery." [ ] mr. babbage considers it as a great mistake to suppose that dr. wollaston's microscopic accuracy depended upon the extraordinary acuteness of the bodily senses; a circumstance, he says, which, if it were true, would add but little to his philosophical character. he is inclined to view it in a far different light, and to see in it one of the natural results of the precision of his knowledge and of the admirable training of his intellectual faculties. * * * * * my history draws towards a conclusion.--sir humphry davy, during the latter days of his life, was cheered by the society and affectionate attentions of his godson, the son of his old friend mr. james tobin.[ ] he had been the companion of his travels, and he was the solace of his declining hours. [ ] this inestimable man died on his plantation at nevis, on the th of october , in the forty-eighth year of his age. he had been resident for some months at rome, where he occupied the second floor of a house in via di pietra, a street that leads out of the corso. during this period, he declined receiving any visitors, and had constantly some one by his side reading light works of interest to him, an amusement which was even continued during his meals. as soon as the account of sir humphry having sustained another paralytic seizure was communicated to lady davy, who was in london at the time, she immediately set off, and so rapidly was her journey performed, that she reached rome in little more than twelve days. dr. john davy, also, hastened from malta, on receiving intelligence of his brother's imminent danger. during his slow and partial recovery from this seizure, he learnt the circumstance of his name having been introduced into parliamentary proceedings, in the following manner. on the th of march , on presenting a petition in favour of the catholic claims from a very great and most respectable meeting at edinburgh, sir james mackintosh, after having mentioned the name of sir walter scott as being at the head of the petitioners, continued thus:--"although not pertinent to this petition, yet connected with the cause, i indulge in the melancholy pleasure of adding to the first name in british literature the first name in british science--that of sir humphry davy. though on a sick-bed at rome, he was not so absorbed by his sufferings as not to feel and express the glow of joy that shot across his heart at the glad tidings of the introduction of a bill which he hailed as alike honourable to his religion and his country." i am assured that the last mark of satisfaction which he evinced from any intelligence communicated to him was on reading the above passage. he showed a pleasure unusual in his state of languor at the justice thus done, in the face of his country, to his consistency, to his zeal for religion and liberty, and to the generous sentiments which cheered his debility. the marks of his pleasure were observed by those who were brought most near to him by the performance of every kind office. although there appeared some faint indications of reviving power, his most sanguine friends scarcely ventured to indulge a hope that his life would be much longer protracted. nor did he himself expect it. the expressions in his will (printed in an appendix) sufficiently testify the opinion he had for some time entertained of the hopelessness of his case. in addition to this will, he left a paper of directions, which have been religiously observed by his widow. he desires, for instance, that the interest arising from a hundred pounds stock may be annually paid to the master of the penzance grammar school, on condition that the boys may have a holiday on his birthday.[ ] there is something singularly interesting in this favourable recollection of his native town, and of the associations of his early youth. it adds one more example to show that, whatever may have been our destinies, and however fortune may have changed our conditions, where the heart remains uncorrupted, we shall, as the world closes upon us, fix our imaginations upon the simplicities of our youth, and be cheered and warmed by the remembrance of early pleasures, hallowed by feelings of regard for the memory of those who have long since slept in the grave. [ ] i understand that the present master, the reverend mr. morris, has expressed his intention to apply the above sum to purchasing a medal, which he intends to bestow as a prize to the most meritorious scholar. with that restlessness which characterises the disease under which sir humphry davy suffered, he became extremely desirous of quitting rome, and of establishing himself at geneva. his friends were naturally anxious to gratify every wish; and lady davy kindly preceded him on the journey, in order that she might at each stage make arrangements for his comfortable reception. apartments were prepared for him at _l'hotel de la couronne_, in the rue du rhone; and at three o'clock on the th of may, having slept the preceding evening at chambery, he arrived at geneva, accompanied by his brother, mr. tobin, and his servant. at four o'clock he dined, ate heartily, was unusually cheerful, and joked with the waiter about the cookery of the fish, which he appeared particularly to admire; and he desired that, as long as he remained at the hotel, he might be daily supplied with every possible variety that the lake afforded. he drank tea at eleven, and having directed that the feather-bed should be removed, retired to rest at twelve. his servant, who slept in a bed parallel to his own, in the same alcove, was however very shortly called to attend him, and he desired that his brother might be summoned. i am informed that, on dr. davy's entering the room, he said, "i am dying," or words to that effect; "and when it is all over, i desire that no disturbance of any kind may be made in the house; lock the door, and let every one retire quietly to his apartment." he expired at a quarter before three o'clock, without a struggle. on the following morning, his friends sismondi[ ] and de candolle were sent for; and the syndics, as soon as the circumstance of his death was communicated to them, gave directions for a public funeral on the monday; at which the magistrates, the professors, the english residents at geneva, and such inhabitants as desired it, were invited to attend. the ceremony was ordered to be conducted after the custom of geneva, which is always on foot--no hearse; nor did a single carriage attend. the cemetery is at plain-palais, some little distance out of the walls of the town. the couronne being at the opposite extremity, the procession was long. [ ] simond de sismondi, the celebrated author of the history of the italian republic. the following was the order of the procession:--[ ] [ ] for these particulars i am indebted to sir egerton brydges. the two syndics, (_in their robes_) { m. mastow, { m. gallatin. magistrates of the republic, { m. fazio, { m. salladin. professors of the college, in their robes, mm. simond de sismondi--a. de candolle. the english. lord eglington, lord twedell, right hon. wm. wyckham, capt. archibald hamilton, mr. campbell, mr. franks, wm. hamilton, esq., ex-ambassador at naples. sir egerton brydges, bart. colonel alcock, captain swinters, mr. alcock, mr. drew, mr. heywood, mr. sitwell, &c. the students of the college. the citizens of geneva. the english service was performed by the rev. john magers, of queen's college, and the rev. mr. burgess. the grave was stated in the public prints to be next to that of his friend the late professor m. a. pictet: this is not the fact. it is far away from it, on the second line of no. , the fourth grave from the end of the west side of the cemetery. * * * * * sir humphry davy having died without issue, his baronetcy has become extinct. at present, the only memorial raised to commemorate the name of this distinguished philosopher is a tablet placed in westminster abbey by his widow. it is thus inscribed:-- to the memory of sir humphry davy, baronet; distinguished throughout the world by his discoveries in chemical science. president of the royal society; member of the national institute of france. born december , at penzance. died may , at geneva, where his remains are interred. the numerous scientific societies of which he was a member, will, no doubt, consecrate his memory. an eloquent eloge has been read by baron cuvier before the institute of france; but it has not yet been published: i have obtained, however, a copy of a speech delivered upon the same occasion, by h. c. van der boon mesch, before the institute of the netherlands. mr. davies gilbert, his early friend and patron, has likewise paid to his memory a just and appropriate testimony of respect and admiration, in an address from the chair of the royal society. the inhabitants of penzance and its neighbourhood, animated by feelings of honourable pride and strong local attachment, will shortly, it is understood, raise a pyramid of massive granite to his memory, on one of those elevated spots of silence and solitude, where he delighted in his boyish days to commune with the elements, and where the spirit of nature moulded his genius in one of her wildest moods. as yet, no intention on the part of the government to commemorate this great philosopher, by the erection of a national monument, has been manifested: for the credit, however, of an age which is so continually distinguished as the most enlightened period in our history, i do hope the disgrace of such an omission may pass from us; although, i confess, it is rather to be wished than expected, when it is remembered that not a niche has been graced by the statue of watt, while the giant iron children of his inventive genius are serving mankind in every quarter of the civilized world. a very erroneous impression would seem to exist with regard to the object and importance of such monuments. they are not to honour the dead, but to improve the living; not to give lustre to the philosopher, but to afford a salutary incentive to the disciple; not to perpetuate discoveries, for they can never be lost; but to animate scientific genius, and to engage it upon objects that may be useful to the commonwealth. let it be remembered, that the ardour of the roman youth was kindled into active emulation, whenever they beheld the images of their ancestors. "nam sæpe audivi, q. maximum, p. scipionem, præterea civitatis nostræ præclaros viros, solitos ita dicere, cùm majorum imagines intuerentur, vehementissimè sibi animum ad virtutem accendi. scilicet non ceram illam, neque figuram tantam vim in sese habere; sed memoriâ rerum gestarum eam flammam egregiis viris in pectore crescere, neque prius sedari, quàm virtus eorum famam atque gloriam adæquaverit."[ ] [ ] sallust. bell. jugurth. the fame of such a philosopher as davy can never be exalted by any frail memorial which man can raise. his monument is in the great temple of nature.[ ] his chroniclers are time and the elements. the destructive agents which reduce to dust the storied urn, the marble statue, and the towering pyramid, were the ministers of his power, and their work of decomposition is a perpetual memorial of his intelligence. [ ] [greek: andrôn gar epiphanôn pasa gê taphos, kai ou stêlôn monon en tê oikeia sêmainei epigraphê, alla kai en tê mê prosêkousê agraphos mnêmê par' hekastô tês gnômês mallon ê tou ergou endiaitatai.--thucydides, b. .] a sketch of the history of chemical science, with a view to exhibit the revolutions produced in its doctrines by the discoveries of sir humphry davy. the rapidity with which chemical opinions have risen into notice, flourished for a while, and then fallen into disrepute, to be succeeded by others equally precarious in their tenure and ephemeral in their popularity, are circumstances which the superficial reasoner has ever deplored, and the sciolist as constantly converted into arguments against the soundness of the science which produced them. the leaves of a season will sprout, expand, and wither; and the dry foliage will be pushed off by the propulsion of new buds; but this last change is not effected in them, until they have absorbed the light and dews of heaven for the nourishment of the plant that bore them; and when even they shall have fallen to the earth, they will farther supply its spreading roots with fresh soil for its future growth and healthy developement; and entering into new combinations, will re-appear in the same tree under fresh forms of usefulness and symmetry. in like manner, chemical theories are but for a season; they are nothing more than general expressions of known facts; they may delight by their ingenuity, as vegetable forms captivate by their beauty, but their real and substantial use is to extend science; and as facts accumulate under their operation, they must give way to others better adapted to the increased growth and expansion of knowledge; nor does the utility of theories cease with their rejection,--they afford objects of analogy and comparison which assist the philosopher in his progress to truth, while their elements furnish materials for future arrangements. were it otherwise, we should behold science in its advancement as a shapeless mass, enlarging by constant appositions, but without a single sign of growth or inward sympathy. if chemical theories have undergone more rapid and frequent changes than those of other branches, the circumstance has arisen from the rapid manner in which new and important facts have been successively added to the general store. whatever may be the vices attributed to chemistry on such occasions, they have belonged to the philosophers engaged in its pursuit, and are no evidence of the frailty of the science itself; and here it must be admitted, that there exists in one portion of mankind a self-love which cannot patiently submit to a change of opinions of which they are either the authors or defenders, while in another there predominates a timidity which naturally leads them, amidst the storm of controversy, to cling to the wreck of a shattered theory, rather than to trust themselves to a new and untried bark. in our review of the history of science, we have frequently to witness how the wisest philosopher has strained truth, for the support of a favourite doctrine, and measured and accommodated facts to theory, instead of adapting theories to facts--but this vice does not belong exclusively to chemical philosophers. huygens, the celebrated dutch astronomer, from some imaginary property in the number _six_, having discovered _one_ of saturn's moons, absolutely declined looking for any more, merely because that one, when added to the four moons of jupiter, and to the one belonging to the earth, made up the required number. such reflections naturally arise on viewing, with a philosophic eye, the progress and modifications of chemical opinions; and it is essential that they should be duly appreciated upon the present occasion; for, before any just estimate can be formed of the talents and services of sir humphry davy, we must thoroughly consider, in all their bearings and relations, the various prejudices with which he had to contend in his efforts to modify a gigantic theory, which enjoyed an unrestrained dominion in the chemical world, and for many years continued to be the pride of france and the admiration of europe. it would be quite foreign to the plan of this sketch,[ ] which the reader must consider as wholly subservient to the object that has been announced, to enquire how far the ancients, in their metallurgical processes, can be said to have exercised the arts of chemistry. equally vain would it be to enter into a history of that system of delusion and imposture, so long practised under the denomination of alchymy. it is only necessary to consider chemistry in its dignified and purely scientific form; and we have only to notice those commanding discoveries and opinions which led to the developement of that system, which the genius of davy was destined to modify. [ ] this historical sketch has no pretensions to originality. it is compiled from the best authors, and from the introduction to sir h. davy's elements of chemical philosophy. the origin of chemistry, as a science, cannot be dated farther back than about the middle of the seventeenth century; and beccher, the contemporary of boyle, who was born at spires in , was unquestionably the first to construct any thing like a general theory. he formed the bold idea of explaining the whole system of the earth by the mutual agency and changes of a few elements. and by supposing the existence of a vitrifiable, a metallic, and an inflammable earth, he attempted to account for the various productions of rocks, crystalline bodies, and metallic veins, assuming a continual interchange of principles between the atmosphere, the ocean, and the solid surface of the globe, and considering the operations of nature as all capable of being imitated by art. albertus magnus had advanced the opinion that the metals were earthy substances impregnated with a certain inflammable principle; but beccher supported the idea of this principle not only as the cause of metallization, but likewise of combustibility. stahl, however, one of the most extraordinary men that germany ever produced, having adopted and amplified this theory, carried off the entire credit of being its founder, and it is universally spoken of as the _stahlian theory_. this theory forms so important a feature in the history of chemistry, and so long maintained its ascendency in the schools, that it will be necessary to give the reader a short summary of its principles. it assumed that all _combustible_ bodies are compounds: one of the constituents being volatile, and therefore easily dissipated during the act of combustion; while the other, being fixed, constantly remained as the residue of the process. this volatile principle, for which stahl invented the term _phlogiston_, was considered as being identical in every species of combustible matter; in short, it was supposed that there was but one principle of combustibility in nature, and that was the imaginary phantom phlogiston, which for nearly a century possessed the schools of europe, and, like an evil spirit, crossed the path of the philosopher at every step, and by its treacherous glare allured him from the steady pursuit of truth; for, whether a substance were combustible or not, its nature could never be investigated without a reference to its supposed relations with phlogiston; its presence, or its absence, was supposed to stamp a character upon all bodies, and to occasion all the changes which they undergo. hence chemistry and combustion came to be in some measure identified; and a theory of combustion was considered the same thing as a theory of chemistry. the identity of phlogiston in all combustible bodies was founded upon observations and experiments of so decisive a nature, that after the existence of the principle itself was admitted, they could not fail to be satisfactory. when phosphorus is made to burn, it gives out a strong flame, much heat is evolved, and the phosphorus is dissipated in fumes, which, if properly collected, will quickly absorb moisture from the atmosphere, and produce an acid liquid known by the name of phosphoric acid. phosphorus then must consist, say the stahlians, of phlogiston and this acid. again--if this liquid be evaporated to a dry substance, mixed with a quantity of charcoal powder, and then heated in a vessel from which the external air is excluded, a _portion_, or the _whole_ of the charcoal will disappear, and phosphorus will be reproduced, possessing all the properties that it had before it was subjected to combustion. in this case, it was supposed that the charcoal restored the phlogiston. there was much plausibility in all this, as well as in the reasoning which followed. since we may employ, with equal success, any kind of combustible body for the purpose of changing phosphoric acid into phosphorus, such as lamp-black, sugar, resin, or even several of the metals, it was concluded that all such bodies contain a common principle which they communicate to the phosphoric acid; and since the new body formed is in all cases identical, the principle communicated must also be identical. hence combustible bodies contain an identical principle, and this principle is phlogiston. the same theory applied with equal force to the burning of sulphur and several of the metals, and to their reconversion by combustible bodies. when lead is kept nearly at a red-heat in the open air for some time, it is converted into a pigment called _red lead_; this is a calx of lead. to restore this calx again to metallic lead, it is only necessary to heat it in contact with almost any combustible matter; all these bodies therefore must contain one common principle, which they communicated to the red lead, and by so doing reconverted it to the state of metal. metals then were regarded as compounds of _calces_ and phlogiston. thus far the theory works glibly enough; but now comes a startling fact, which was long unnoticed by the blind adherents of stahl, or, if noticed, intentionally overlooked. it was observed very early, that when a metal was converted into a calx, its weight was increased. when this difficulty first forced itself upon the attention of the phlogistians, it was necessary that they should either explain it, or at once abandon their theory. they accordingly endeavoured to evade the difficulty, not only by asserting that phlogiston had no weight, but that it was actually endowed with a principle of levity. it was not possible, however, that any rational notions should have been entertained upon the subject of combustion, at a period when the composition of the atmosphere even was unknown. let us therefore follow the stream of discovery, skimming the surface merely, as it flowed onward towards quite a new field of science--pneumatic chemistry. boyle and hooke, who had improved the air-pump invented by otto de guericke, of madenburgh, first used this apparatus for investigating the properties of air; and they concluded from their experiments that air was absolutely necessary to combustion and respiration, and that one part of it only was employed in these processes; and hooke formed the sagacious conclusion, that this principle is the same as the substance fixed in nitre, and that combustion is a chemical process, the solution of the burning body in elastic fluid, or its union with this matter. mayow, of oxford, in , published his treatises on the nitro-aërial spirit, in which he advanced opinions similar to those of boyle and hooke, and supported them by a number of original and curious experiments. dr. hales, about , resumed the investigations commenced with so much success by boyle, hooke, and mayow; and endeavoured to ascertain the chemical relations of air to other substances, and to ascertain by statistical experiments the cases in nature, in which it is absorbed or emitted. he obtained a number of curious and important results; he disengaged elastic fluids from various substances, and drew the conclusion, that air was a chemical element in many compound bodies, and that flame resulted from the action and reaction of aërial and sulphurous particles; but all his reasonings were contaminated with the notion of one elementary principle constituting elastic matter, and modified in its properties by the effluvia of solid or fluid bodies. the light of pneumatic science which had dawned under hooke, mayow, and hales, burst forth in splendour under the ascendency of that constellation of british science, black, cavendish, and priestley. in , dr. black published his researches on calcareous, magnesian, and alkaline substances, by which he proved the existence of a gaseous body, perfectly distinct from the air of the atmosphere. he showed, that quick-lime differed from marble and chalk by not containing this substance, which he proved to be a weak acid, capable of being expelled from alkaline and earthy bodies by stronger acids. as nothing is more instructive than to enquire into the circumstances which have led to a great discovery, i quote with pleasure the following passage from dr. thomson's history of chemistry. "it was the good fortune of chemical science that, at this time ( ), the opinions of professors were divided concerning the manner in which certain lithonthriptic medicines, particularly lime-water, acted in alleviating the excruciating pains of the stone and gravel. the students usually partake of such differences of opinion: they are thereby animated to more serious study, and science gains by their emulation. "all the medicines which were then in vogue as solvents of calculi had a greater or less resemblance to caustic potash or soda; substances so acrid, when in a concentrated state, that in a short time they reduce the fleshy parts of the animal body to a mere pulp. they all seemed to derive their efficacy from quick-lime, which again derived its power from the fire. it was therefore very natural for them to ascribe its power to igneous matter imbibed from the fire, retained by the lime, and communicated by it to alkalies which it renders powerfully acrid. it appears from dr. black's note-books, that he originally entertained the opinion, that caustic alkalies acquired igneous matter from quick-lime. in one of them, he hints at some way of catching this matter as it escapes from lime, while it becomes mild by exposure to the air; but on the opposite blank page is written, 'nothing escapes--the cup rises considerably by absorbing air.' a few pages further on, he compares the loss of weight sustained by an ounce of chalk when calcined, with its loss while dissolved in muriatic acid. "these experiments laid open the whole mystery, as appears by another memorandum. 'when i precipitate lime by a common alkali, there is no effervescence: the air quits the alkali for the lime; but it is lime no longer, but c. c. c: it now effervesces, which good lime will not.'--what a multitude of important consequences naturally flowed from this discovery! he now knew to what the causticity of alkalies is owing, and how to induce it, or remove it, at pleasure. the common notion was entirely reversed. lime imparts nothing to the alkalies; it only removes from them a peculiar kind of air (_carbonic acid gas_) with which they were combined, and which prevented their natural caustic properties from being developed. all the former mysteries disappear, and the greatest simplicity appears in those operations of nature which before appeared so intricate and obscure." dr. thomson afterwards observes,--"the discovery which dr. black had made, that marble is a combination of lime and a peculiar substance, to which he gave the name of _fixed air_, began gradually to attract the attention of chemists in other parts of the world. it was natural, in the first place, to examine the nature and properties of this fixed air, and the circumstances under which it is generated. it may seem strange and unaccountable that dr. black did not enter with ardour into this new career which he had himself opened, and that he allowed others to reap the corn after having himself sown the grain. yet he did take some steps towards ascertaining the properties of _fixed air_; though i am not certain what progress he made. he knew that a candle would not burn in it, and that it is destructive to life, when any living animal attempts to breathe it. he knew that it is formed in the lungs during the breathing of animals, and that it is generated during the fermentation of wine and beer. whether he was aware that it possesses the properties of an acid, i do not know; though with the knowledge which he possessed that it combines with alkalies and alkaline earths, and neutralizes them, or at least blunts and diminishes their alkaline properties, the conclusion that it partook of acid properties was scarcely avoidable. all these, and probably some other properties of _fixed air_, he was in the constant habit of stating in his lectures from the very commencement of his academical career; though, as he never published any thing on the subject himself, it is not possible to know exactly how far his knowledge of the properties of _fixed air_ extended. the oldest manuscript copy of his lectures that i have seen was taken down in writing in the year ; and before that time mr. cavendish had published his paper on _fixed air_ and _hydrogen gas_, and had detailed the properties of each. it was impossible from the manuscript of dr. black's lectures, to know which of the properties of _fixed air_ stated by him were discovered by himself, and which were taken from mr. cavendish." an idea so novel and important as that of an air possessing properties quite different from that of the atmosphere, existing in a fixed and solid state in various bodies, was not received without doubt, and even opposition. several german enquirers endeavoured to controvert it. meyer attempted to show that limestone became caustic, not by the emission of elastic matter, but by combining with a peculiar substance in the fire; the loss of weight, however, was wholly inconsistent with such a view of the question: and bergman at upsal, macbride in ireland, keir at birmingham, and cavendish in london, fully demonstrated the truth of the opinion of black, and a few years were sufficient to establish his theory upon an immutable foundation, and to open a new road to most important discoveries. the knowledge of one elastic fluid, entirely different in its properties from air, very naturally suggested the probability of the existence of others. the processes of fermentation which had been observed by the ancient chemists, and those by which hales had disengaged and collected elastic substances, were now regarded under a novel point of view; and the consequence was, that a number of new bodies, possessed of very extraordinary properties, were discovered. mr. cavendish, about the year , invented an apparatus for examining elastic fluids confined by water, which has since been called the _hydro-pneumatic_ apparatus. he discovered inflammable air, and described its properties; he ascertained the relative weights of fixed air, inflammable air, and common air, and made a number of beautiful and accurate experiments on the properties of these elastic substances. dr. priestley, in , entered the same path of enquiry; and principally by repeating the processes of hales, added a number of most important facts to this department of chemical philosophy. he discovered nitrous air, nitrous oxide, and dephlogisticated air, (oxygen) and by substituting mercury for water in the pneumatic apparatus, ascertained the existence of several aëriform bodies which are rapidly absorbable by water; such as muriatic acid gas, sulphurous acid gas, and ammonia. scheele, independently of priestley, also discovered several of the aëriform bodies; he ascertained likewise the composition of the atmosphere; he brought to light fluoric acid, prussic acid, and the substance which he termed _dephlogisticated marine acid_, the oxy-muriatic acid of the french school, and the chlorine of davy. sir humphry davy, in the preface to his chemical philosophy, observes that black, cavendish, priestley, and scheele, were undoubtedly the greatest chemical discoverers of the eighteenth century; and that their merits are distinct, peculiar, and of the most exalted kind. he thus defines them: "black made a smaller number of original experiments than either of the other philosophers; but being the first labourer in this new department of the science, he had greater difficulties to overcome. his methods are distinguished for their simplicity; his reasonings are admirable for their precision; and his modest, clear, and unaffected manner is well calculated to impress upon the mind a conviction of the accuracy of his processes, and the truth and candour of his researches. "cavendish was possessed of a minute knowledge of most of the departments of natural philosophy: he carried into his chemical researches a delicacy and precision, which have never been exceeded: possessing depth and extent of mathematical knowledge, he reasoned with the caution of a geometer upon the results of his experiments; and it may be said of him, what, perhaps, can scarcely be said of any other person, that whatever he accomplished, was perfect at the moment of its production. his processes were all of a finished nature; executed by the hand of a master, they required no correction; the accuracy and beauty of his earliest labours even have remained unimpaired amidst the progress of discovery, and their merits have been illustrated by discussion and exalted by time. "dr. priestley began his career of discovery without any general knowledge of chemistry, and with a very imperfect apparatus. his characteristics were ardent zeal and the most unwearied industry. he exposed all the substances he could procure to chemical agencies, and brought forward his results as they occurred, without attempting logical method or scientific arrangement. his hypotheses were usually founded upon a few loose analogies; but he changed them with facility; and being framed without much effort, they were relinquished with little regret. he possessed in the highest degree ingenuousness and the love of truth. his manipulations, though never very refined, were always simple, and often ingenious. chemistry owes to him some of her most important instruments of research, and many of her most useful combinations; and no single person ever discovered so many new and curious substances. "scheele possessed in the highest degree the faculty of invention; all his labours were instituted with an object in view, and after happy or bold analogies. he owed little to fortune or to accidental circumstances: born in an obscure situation, occupied in the duties of an irksome employment, nothing could damp the ardour of his mind, or chill the fire of his genius; with very small means, he accomplished very great things. no difficulties deterred him from submitting his ideas to the test of experiment. occasionally misled in his views, in consequence of the imperfection of his apparatus, or the infant state of the enquiry, he never hesitated to give up his opinions the moment they were contradicted by facts. he was eminently endowed with that candour which is characteristic of great minds, and which induces them to rejoice as well in the detection of their own errors, as in the discovery of truth. his papers are admirable models of the manner in which experimental research ought to be pursued; and they contain details on some of the most important and brilliant phenomena of chemical philosophy." the discovery of the gases, of a new class of bodies more active than any others in most of the phenomena of nature and art, could not fail to modify the whole theory of chemistry, and, under the genius of lavoisier, it ultimately led to the establishment of those new doctrines, which it is the principal object of this history to expound; but before this task can be accomplished, it will be necessary to consider the rise and progress of opinion concerning chemical attraction, and heat and light, since these subjects are too intimately interwoven with the _anti-phlogistic_ system to be separated from any examination of its principles. boyle, says sir humphry davy, was one of the most active experimenters, and certainly the greatest chemist of his age. he introduced the use of _tests_, or _re-agents_, active substances for detecting the presence of other bodies: he overturned the ideas which at that time were prevalent, that the results of operations by fire were the real elements of things; and he ascertained a number of important facts respecting inflammable bodies, and alkalies, and the phenomena of combination; but neither he nor any of his contemporaries endeavoured to account for the changes of bodies by any fixed principles. the solutions of the phenomena were attempted either on rude mechanical notions, or by occult qualities, or peculiar subtile spirits or ethers, supposed to exist in the different bodies. and it is to the same great genius who developed the laws that regulate the motions of the heavenly bodies, that chemistry owes the first distinct philosophical elucidations of the powers which produce the changes and apparent transmutations of the substances belonging to the earth. "sugar dissolves in water, alkalies unite with acids, metals dissolve in acids. is not this," says newton, "on account of an attraction between their particles? copper dissolved in aqua fortis is thrown down by iron. is not this because the particles of the iron have a stronger attraction for the particles of the acid, than those of copper; and do not different bodies attract each other with different degrees of force?" in , geoffroy endeavoured to ascertain the relative attractive powers of bodies for each other, and to arrange them, under the form of a table, in an order in which these forces, which he named affinities, were expressed. concerning the nature of heat, there are two opinions which have ever divided the chemical world. the one considers it merely as a property of matter, and that it consists in an undefinable motion, or vibration of its particles; the other, on the contrary, regards it as a distinct and subtile substance, _sui generis_. each of these opinions has been supported by the greatest philosophers, and for a long period the arguments on both sides appeared equally plausible and forcible. the discovery of dr. black, however, gave a preponderance to the scale in favour of its materiality. "it was during his residence in glasgow, between the year and ," says dr. thomson, "that he brought to maturity those speculations concerning the combination of _heat_ with _matter_, which had frequently occupied a portion of his thoughts." before dr. black's discovery, it was universally supposed that solids were converted into liquids by a small addition of heat, after they have been once raised to the melting point, and that they returned again to the solid state on a very small diminution of the quantity of heat necessary to keep them at that temperature. an attentive view, however, of the phenomena of liquefaction and solidification gradually led this sagacious philosopher to a different conclusion. by observations which it is unnecessary to detail, he became satisfied that when ice is converted into water, it unites with a quantity of heat, without having its temperature increased; and that when water is frozen into ice, it gives out a quantity of heat without having it diminished. the heat thus combined, then, is the cause of the fluidity of the water; and as it is not sensible to the thermometer, dr. black called it _latent heat_. there is such an analogy between the cessation of thermometric expansion during the liquefaction of ice, and during the conversion of water into steam, that there could be no hesitation about explaining both in the same way. dr. black, therefore, immediately concluded that, as water is ice united to a certain quantity of _latent_ heat, so steam is water united to a still greater quantity. this beautiful theory enables us to understand phenomena in nature which were previously quite inexplicable. we now comprehend how the thaw which supervenes after intense frost, should so slowly melt the wreaths of snow and beds of ice. had, indeed, the transition of water from its solid into its liquid state not been accompanied by this great change in its relation to heat, every thaw would have occasioned a frightful inundation, and a single night's frost must have solidified our rivers and lakes. neither animal nor vegetable life could have subsisted under such sudden and violent transitions. it would appear, then, that water, during the act of freezing, is acted upon by two opposite powers: it is deprived of heat by exposure to a medium whose temperature is below °; and it is supplied with heat by the evolution of that principle from itself, _viz._ of that portion which constituted its fluidity. as these powers are exactly equal, the temperature of the water must remain unchanged till the latent heat, necessary to its fluidity, is all evolved. although these facts have been admitted by all, it has been contended by many that the absorption of heat by bodies is the necessary _effect_, and not the efficient _cause_, of change of form,--the consequence of what has been called a change of their _capacity_: thus ice, it is supposed, in becoming water, has its capacity for heat increased, and the absorption of heat is a consequence of such increased capacity. this theory, however, is deficient, inasmuch as it fails to explain the cause of that change of form, which is assumed to account for the increase of capacity. light, like heat, has been considered by some philosophers as a subtile fluid filling space, and rendering bodies visible by the undulations into which it is thrown; while others, with newton at their head, regard it as a substance consisting of small particles, constantly separating from luminous bodies, moving in straight lines, and rendering objects visible by passing from them and entering the eye. the late experiments of dr. young would incline us to prefer the undulatory to the corpuscular hypothesis. by this preliminary sketch, the reader has been prepared for viewing with advantage the theory of lavoisier; in the construction of which he will see little more than a happy generalization of the several discoveries which have been enumerated. indeed, this observation will apply to all great systems of philosophy; facts, developed by successive enquirers, go on accumulating, until, after an interval, a happy genius arises who connects and links them together; and thus generally receives that meed of praise which, in stricter justice, would be apportioned and awarded to the separate contributors. it is far from my intention to disparage the merits of lavoisier; but the materials of his system were undoubtedly furnished by black, priestley, and cavendish. the most important modification of the phlogistic theory--for there were several others--may be said to be that suggested by dr. crawford. dr. priestley had found that the air in which combustibles were suffered to burn till they were extinguished, underwent a very remarkable change, for no combustible would afterwards burn in it, and no animal could breathe it without suffocation. dr. crawford, like many others, concluded, that this change was owing to phlogiston; but he for the first time applied dr. black's doctrine of _latent_ heat, for the explanation of the origin of the heat and light which appear during the process. according to this philosopher, the phlogiston of the combustible combines, during combustion, with the air, and at the same time separates the caloric and light with which that fluid had been previously united. the heat and the light, then, which appear during combustion, exist previously in the air. this theory was very different from stahl's, and certainly a great deal more satisfactory; but still the question--_what is phlogiston?_ remained to be answered. mr. kirwan attempted to answer it, and to prove that phlogiston is no other than hydrogen. this opinion, which mr. kirwan informs us was first suggested by the discoveries of dr. priestley, met with a very favourable reception from the chemical world, and was adopted, amongst many others, by mr. cavendish. the object of mr. kirwan was to prove, that hydrogen exists as a component part of every combustible body; that during combustion it separates from the combustible body, and combines with the oxygen of the air. at the same time, lavoisier was engaged in examining the experiment of bayen, and those of the british philosophers. bayen, in , had shown that mercury converted into a calx, or earth, by the absorption of air, could be revived without the addition of any inflammable substance; and hence he concluded, that there was no necessity for supposing the existence of any peculiar principle of inflammability, in order to account for the calcination of metals; but he formed no opinion respecting the nature of the air produced from the _calx_ of mercury. lavoisier, in , showed that it was an air, which supported flame and respiration better than common air, which he afterwards named oxygen: the same substance that priestley and scheele had procured from other metallic bodies the year before, and had particularly described. lavoisier also discovered that the same air is produced during the revivification of metallic calces by charcoal, as that which is emitted during the calcination of limestones; hence he concluded, that this elastic fluid is composed of oxygen and charcoal: and from his experiments on nitrous acid and oil of vitriol, he also inferred that this gas entered into the composition of these substances. lavoisier was now enabled to explain the phenomena of combustion, without having recourse, to phlogiston: a principle merely supposed to exist, because combustion could not be explained without it. his new theory depends upon the two laws discovered by himself and dr. black; _viz._ that when a combustible is raised to a certain temperature, it begins to combine with the oxygen of the atmosphere, and that this oxygen during its condensation lets go the _latent_ caloric, and the light with which it was combined while in the gaseous state. hence their appearance during every combustion. hence also the change which the combustible undergoes in consequence of combustion. it followed from this view, that the metallic _calces_ were combinations of metals with oxygen; and on examining the products of certain inflammable bodies, and finding them to be acid, the conclusion was extended by a plausible analogy to other acids whose bases were unknown, and the general proposition was established that oxygen was the universal principle of acidity; that acids resulted from the union of a peculiar combustible base, called the _radical_, with the common principle, oxygen, technically termed the _acidifier_. these views, regarding the phenomena of combustion and acidification, may be considered as constituting what has been termed the _anti-phlogistic system_. it was some time, however, after this system was promulgated, before its author was able to gain a single convert, notwithstanding his unwearied assiduity, and the great weight which his talents, his reputation, his fortune, and his situation naturally gave him. at length, m. berthollet, at a meeting of the academy of sciences in , solemnly renounced his old opinions, and declared himself a convert. fourcroy followed his example; and two years afterwards morveau, during a visit to paris, was prevailed upon to embrace the new doctrine. the theory of lavoisier, soon after it had been framed, received an important confirmation from the two grand discoveries of mr. cavendish, respecting the composition of water and nitric acid, and the elaborate and beautiful investigations of berthollet into the nature of ammonia; by which, phenomena, before anomalous, were shown to depend upon combinations of aëriform matter. the notion of phlogiston, however, was still defended with remarkable tenacity by many distinguished philosophers. mr. kirwan, who considered hydrogen as the universal principle of combustibility, undertook to prove that this element entered into the composition of every body of the kind: a single exception, of course, must necessarily prove fatal to the theory. mr. kirwan, fortunately for the french chemists, founded his reasonings on the inaccurate experiments of other chemists; and thus did he promote the popularity of the anti-phlogistic system by the weakness of the arguments by which he assailed it. lavoisier and his associates saw at once the important uses which might be made of this essay: by refuting an hypothesis which had been embraced by the most respectable chemists in europe, their cause would receive an _éclat_ which would make it irresistible. the essay was accordingly translated into french, and each of the sections into which it was divided was accompanied by a refutation. four of the sections were refuted by lavoisier, three by berthollet, three by fourcroy, two by morveau, and one by monge. mr. cavendish, in a paper communicated to the royal society in the year , drew a comparison between the phlogistic and anti-phlogistic theories, and showed that each of them was capable of explaining the phenomena in a satisfactory manner; he however, at the same time, gave the reasons which induced him to prefer the earlier view. in the execution of this task, unlike mr. kirwan, he never advanced a single opinion which he had not put to the test of experiment; and he never suffered himself to go any farther than his experiments would warrant. this paper, therefore, the french chemists were unable to refute, and they were accordingly wise enough to pass it over without notice. had it been possible to have preserved the phlogistic hypothesis, mr. cavendish would have saved it-- "si pergama dextrâ defendi possent, etiam hâc defensa fuissent." "sooner or later," says sir humphry davy, "that doctrine which is an expression of facts, must prevail over that which is an expression of opinion. the most important part of the theory of lavoisier was merely an arrangement of the facts relating to the combinations of oxygen: the principle of reasoning which the french school professed to adopt was, that every body which was not yet decompounded, should be considered as simple; and though mistakes were made with respect to the results of experiments on the nature of bodies, yet this logical and truly philosophical principle was not violated; and the systematic manner in which it was enforced was of the greatest use in promoting the progress of science." till , there had been no attempt to reform the nomenclature of chemistry; the names applied by discoverers to the substances which they made known were still employed. some of these names, which originated amongst the alchymists, were of the most barbarous kind; few of them were sufficiently definite or precise, and most of them were founded upon loose analogies, or upon false theoretical views. "it was felt by many philosophers, particularly by the illustrious bergman, that an improvement in chemical nomenclature was necessary; and in , mm. lavoisier, morveau, berthollet, and fourcroy, presented to the world a plan for an almost entire change in the denomination of chemical substances, founded upon the idea of calling simple bodies by some names characteristic of their most striking qualities, and of naming compound bodies from the elements which composed them." there was, besides, a secret feeling in the breasts of the associated chemists, which, no doubt, had its influence in suggesting and promoting such a scheme. the views of lavoisier had so changed the face of chemistry, as almost to have rendered it a new science: by adopting a new nomenclature, they identified, as it were, all the discoveries of the day with the new theory, and thus appropriated to france the original and entire merit of the system. it is impossible to pass over this subject without a comment. lavoisier was unquestionably indebted to dr. black for the support, if not for the suggestion, of the most brilliant part of his theory of combustion; and yet he attempted even to conceal the name of the discoverer of _latent heat_. how far lavoisier was really culpable, and whether he did not intend to do full justice to all the claims of his predecessors, cannot now be known; as he was cut off in the midst of his career, while so many of his scientific projects remained unexecuted. from the posthumous works of lavoisier, there is some reason for believing that, if he had lived, he would have done justice to all parties; but there is no doubt that dr. black, in the mean time, thought himself aggrieved by the publication of several of lavoisier's papers in the "mémoires de l'académie," and that he formed the intention of doing himself justice, by publishing an account of his own discoveries: this intention, however, was unfortunately thwarted and prevented by bad health. but to return to the subject of nomenclature. sir h. davy continues--"the new nomenclature was speedily adopted in france; under some modifications, it was received in germany; and, after much discussion and opposition, it became the language of a new and rising generation of chemists in england. it materially assisted the diffusion of the anti-phlogistic doctrine, and even facilitated the general acquisition of the science; and many of its details were contrived with much address, and were worthy of its celebrated authors." on the general adoption of this new theory of chemistry, it must be admitted that its authors displayed an intemperate triumph wholly unworthy of them. they held a festival, at which madame lavoisier, in the habit of a priestess, burnt the works of stahl on an altar erected for the occasion, while solemn music played a requiem to his departed system! sir humphry davy, in speaking of the merits of lavoisier, observes that "he must be regarded as one of the most sagacious of the chemical philosophers of the last century; indeed, except cavendish, there is no other enquirer who can be compared to him for precision of logic, extent of view, and sagacity of induction. his discoveries are few, but he reasoned with extraordinary correctness upon the labours of others. he introduced weight and measure, and strict accuracy of manipulation into all chemical processes. his mind was unbiassed by prejudice; his combinations were of the most philosophical nature; and in his investigations upon ponderable substances, he has entered the true path of experiment with cautious steps, following just analogies, and measuring hypotheses by their simple relations to facts." it will be scarcely possible for a future generation of philosophers to imagine with what an undisciplined ardour the anti-phlogistic system, thus enhanced by a new and fascinating nomenclature, was supported throughout europe. facts only were appreciated in proportion to the evidence they furnished of its truth; and a discovery even required the sanction of its authority as the passport to notice and regard. the least expression of doubt, as to the validity of any point in its doctrines, exposed the sceptic to a host of assailants, and fortunate was he if he escaped the fate of peter ramus, or of those who ventured to question the infallibility of that great despot of another age, aristotle. in no country of europe did this feeling manifest itself to a greater extent than in england. there was perhaps a political prejudice co-operating upon the occasion: it is very difficult, under any circumstances, to avoid connecting the man and his works. the fate of lavoisier[ ] was truly affecting, and by a species of retributive justice, he received the sympathy of the world in the homage paid to his system; while the atrocity of his assassination, on which every englishman dwelt with horror, appeared to be thus heightened by every praise bestowed upon his merits. [ ] lavoisier perished on the scaffold at the age of fifty-one, during the sanguinary reign of robespierre. the fury of the revolutionary leaders of france was particularly directed against the farmers-general of the revenue, who were all executed, with the exception of a single individual, a m. de verdun. sixty of them were guillotined at the same time, in consequence of a report of dupin, a frantic member of the convention. the revolutionary tribunal adopted a general formula, as the ground of their condemnation, which is curious as applied to lavoisier, who was declared guilty of having "adulterated snuff with water and ingredients destructive of the health of the citizens." the unfortunate philosopher requested time to complete some experiments on respiration. the reply of coffinhal, the president, was, that "the republic did not want savans or chemists, and that the course of justice could not be suspended." it is not the least surprising circumstance in the history of this system, that with such a blind and idolatrous admiration of its principles, so few facts should have been distorted. it is true that, from the belief that combustion could never take place without the presence of oxygen, the elementary principle of scheele became, according to these views, a compound of oxygen and an acid; and the name of _dephlogisticated marine acid_ was exchanged for that of _oxy-muriatic acid_, a circumstance which spread a cloud of error over the science, and perhaps retarded its progress in a greater degree than is generally imagined. in like manner, the chemist neglected to avail himself of the hint which, under other impressions, would have proved an important clue to discovery, _viz._ the acid properties of sulphuretted hydrogen. we have now arrived at that stage in our history, when it may with propriety and advantage be asked--what has davy done in correcting error, or in advancing truth? the answer to this question will be nothing more than a summary of those discoveries which have been successively investigated during the progress of the present work. the new doctrines of chemistry were highly instrumental in encouraging more extended investigations into all the different productions of nature and art; and we may observe, that one of the first efforts of sir humphry davy was to improve our knowledge of the nature and habitudes of the tanning and astringent principles of vegetables,--an enquiry which had been commenced by seguin and proust. in pursuing even the most beaten path, he was sure to discover objects of novelty. look at his early experiments on the cane, and on the straw of wheat, barley, and hay, and we shall see how magically he raised from their ashes a new flower of knowledge. he soon, however, quitted the track of other experimentalists; although we learn from the whole tenor of his researches, that he could obey as well as he could command, and he could act in the ranks, although he more frequently appeared as a general in the field of science. sir humphry davy has observed, that "at the time when the anti-phlogistic theory was established, electricity had little or no relation to chemistry. the grand results of franklin respecting the cause of lightning, had led many philosophers to conjecture, that certain chemical changes in the atmosphere might be connected with electrical phenomena; and electrical discharges had been employed by cavendish, priestley, and van-marum, for decomposing and igniting bodies; but it was not till the era of the wonderful discovery of volta, in , of a new electrical apparatus, that any great progress was made in chemical investigation by means of electrical combinations. "nothing tends so much to the advancement of knowledge as the application of a new instrument. the native intellectual powers of men in different times are not so much the causes of the different success of their labours, as the peculiar nature of the means and artificial resources in their possession. independent of vessels of glass, there could have been no accurate manipulations in common chemistry: the air-pump was necessary for the investigation of the properties of gaseous matter; and without the voltaic apparatus, there was no possibility of examining the relations of electrical polarities to chemical attractions." there is a candour in this statement which we cannot but admire. nor does the admission diminish the glory of him who, by the application of such new instruments of research, was enabled to penetrate into the hidden mysteries of nature. what avails the telescope, without the eye of the observer? to davy, the voltaic apparatus was the _golden branch_, by which he subdued the spirits that had opposed the advance of former philosophers; but what would its possession have availed him, had not his genius, like the ancient sibyl, pointed out its use and application? it will be seen that he was thus enabled, not only to discover laws which are in constant operation, modifying the forms of matter, and influencing all the operations of chemistry, but, by applying them, to determine the elements of the fixed alkalies to be oxygen and a metallic base: a fact obviously opposed to the idea of oxygen being the general principle of acidity; for here it was the principle of alkalinity, if it may be so expressed. this was shaking the corner-stone of the edifice, and his subsequent researches into the nature of oxy-muriatic acid may be said to have overthrown it; for if either of the elements of this body can be considered as the acidifier, it is hydrogen. the consequences which flowed from this truth were of the highest importance, not only in correcting errors, which the progress of discovery, instead of rectifying, was actually multiplying, but in leading to the developement of new bodies. iodine might have been recognised as an elementary body; but its relations to oxygen and hydrogen would probably have remained unknown, had not a knowledge of the true character of chlorine assisted the enquiry. the same observation will apply to the recently discovered body, bromine. in like manner has the chemist been led, by the chloridic theory, to a more accurate acquaintance with the composition of the fluoric, hydriodic, and hydrocyanic acids; while he has also learnt that hydrogen alone can convert certain undecompounded bases into well characterised acids, without the aid of oxygen. the same discovery has completely changed all our opinions with regard to a very important series of saline combinations, and developed the existence of new compounds of a most interesting description. thus, then, has the _acidifying_ hypothesis of lavoisier been overturned, and a new theory constructed out of its ruins, which acknowledges no distinct element as the one imparting to matter the characters of an acid. equally complete has been the downfall of the theory of combustion. the discovery of the true nature of chlorine was, in itself, sufficient to show that bodies might combine, with the phenomena of heat and light, without the presence of oxygen; but davy has brought a mass of evidence from other sources in proof of the same truth. he has shown that, whenever the chemical forces which determine either composition or decomposition are energetically exercised, the phenomena of combustion, or incandescence, with a change of properties, are displayed. he has therefore annulled the distinction between supporters of combustion and combustibles, since he has shown that, in fact, one substance frequently acts in both capacities, being a supporter _apparently_ at one time, and a combustible at another. but in both cases the heat and light depend on the same cause, and merely indicate the energy and rapidity with which reciprocal attractions are exerted. thus sulphuretted hydrogen is a combustible with oxygen and chlorine; a supporter with potassium. sulphur, with chlorine and oxygen, has been called a combustible basis; with metals, it acts the part of a supporter. in like manner, potassium unites so powerfully with arsenic and tellurium, as to produce the phenomena of combustion. nor can we ascribe the appearances to the liberation of latent heat, in consequence of condensation of volume. the protoxide of chlorine, a body destitute of any combustible constituent, at the instant of decomposition evolves light and heat with explosive violence; and its volume becomes one-fifth greater. chloride and iodide of azote, compounds alike destitute of any inflammable matter, according to the ordinary belief, are resolved into their respective elements with tremendous force of inflammation; and the first expands into more than six hundred times its bulk. now, instead of heat and light, a prodigious degree of _cold_ ought to accompany such an expansion, according to the hypothesis of latent heat. other instances might be cited, and other arguments adduced on the same subject, but time and space fail me.[ ] [ ] the reader who wishes for further details, will consult with advantage the article combustion in dr. ure's dictionary of chemistry; a work to which i acknowledge myself much indebted on this and other occasions. such, then, are the facts developed by the experimental researches of sir humphry davy; from which it follows, that-- . combustion is not necessarily dependent on the agency of oxygen. . that it cannot be regarded as dependent upon any peculiar principle or form of matter, but must be considered as a general result of intense chemical action. . that the evolution of light and heat cannot be ascribed simply to a gas parting with its latent store of those ethereal fluids. . that, since all bodies which act powerfully upon each other are in the opposite electrical relations of positive and negative, the evolution of heat and light may depend upon the annihilation of these opposite states, which will happen whenever they combine. thus has sir h. davy, by refuting the opinions of the french philosophers, respecting the relations of oxygen to the phenomena of combustion, and the nature of its products, removed the pillars on which the fabric of the anti-phlogistic rested, and reduced the generalization of lavoisier to isolated collections of facts; the sound logic, however,--the pure candour, the numerical precision of inference which characterise the labours of the french philosopher, will cause his name to be held in everlasting admiration. the downfall of his doctrine is the natural result of the progress of truth; the same fate may attend our present systems, but the facts discovered through their means are unchangeable and eternal; and it is upon them alone that the fame of the chemist must ultimately rest. in sciences collateral to chemistry, the researches of davy have cast a reflected lustre. in geology, his discovery of the composition of the earths, has opened a new path of investigation; while his examination of the water and gaseous matter so frequently enclosed in the cavities of quartz, has given no small degree of support to the hypothesis of the plutonists; above all, his results connected with the decomposition and transfer of different elements by voltaic influence, has already explained many phenomena relating to metallic veins; and the late researches of mr. fox must lead us to the conclusion, that electric powers are still in operation in the recesses of the earth; and that mineral veins are not only the cabinets of nature, but still her active laboratories. these cursory observations upon the discoveries of sir h. davy relate merely to the changes they have effected in the general theory of chemistry. i might recapitulate the numerous researches by which he has extended our knowledge upon particular subjects; but i have so fully entered into the consideration of them in the body of my work, that i consider such a tax upon the patience of my reader would be both unfair and unnecessary. i shall therefore _conclude_ my long and arduous labour, by enumerating the different memoirs communicated by this distinguished philosopher to the royal society; and also the several works which he published at different periods of his brilliant but too fleeting career. . an account of some galvanic combinations, formed by single metallic plates and fluids, analogous to the galvanic apparatus of m. volta. _read june , ._ . an account of some experiments and observations on the constituent parts of certain astringent vegetables, and on their operation in tanning. _february , ._ . an account of some analytical experiments on a mineral production from devonshire, consisting principally of alumina and water. _february , ._ . on a method of analysing stones containing a fixed alkali, by means of boracic acid. _may , _. * _for the above papers, the society awarded him the copley medal._ . the bakerian lecture.--on some chemical agencies of electricity. _november , ._ ** _for this memoir, he received the prize of the french institute._ . the bakerian lecture.--on some new phenomena of chemical changes produced by electricity, particularly the decomposition of the fixed alkalies, and the exhibition of the new substances which constitute their bases; and on the general nature of alkaline bodies. ? _read november , ._ . electro-chemical researches on the decomposition of the earths; with observations on the metals obtained from the alkaline earths; and on the amalgam procured from ammonia. _june , ._ . the bakerian lecture.--an account of some new analytical researches on the nature of certain bodies, particularly the alkalies, phosphorus, sulphur, carbonaceous matter, and the acids hitherto uncompounded; with some general observations on chemical theory. _december , ._ . new analytical researches on the nature of certain bodies; being an appendix to the bakerian lecture for . _february ._ . the bakerian lecture for . on some new electro-chemical researches on various objects, particularly the metallic bodies from the alkalies and earths; and on some combinations of hydrogen. _november , ._ . researches on the oxy-muriatic acid, its nature and combinations; and on the elements of muriatic acid; with some experiments on sulphur and phosphorus, made in the laboratory of the royal institution. _read july , ._ . the bakerian lecture for . on some of the combinations of oxy-muriatic gas and oxygen, and on the chemical relations of those principles to inflammable bodies. _november , ._ . on a combination of oxy-muriatic gas and oxygen gas. _february , ._ . on some combinations of phosphorus and sulphur, and on some other subjects of chemical enquiry. _june , ._ . on a new detonating compound; in a letter to sir joseph banks, bart. f.r.s. _november , ._ . some further observations on a new detonating substance. _july , ._ . some experiments and observations on the substances produced in different chemical processes on fluor spar. _july , ._ . an account of some new experiments on the fluoric compounds; with some observations on other objects of chemical enquiry. _february , ._ . some experiments and observations on a new substance, which becomes a violet-coloured gas by heat. _january , ._ . further experiments and observations on iodine. _read june , ._ . some experiments on the combustion of the diamond, and other carbonaceous substances. _june , ._ . some experiments and observations on the colours used in painting by the ancients. _february , ._ . some experiments on a solid compound of iodine and oxygen, and on its chemical agencies. _april , ._ . on the action of acid upon the salts usually called _hyper-oxymuriates_, and on the gases produced from them. _may , ._ . on the _fire-damp_ of coal mines, and on methods of lighting the mine, so as to prevent explosion. _november , ._ . an account of an invention for giving light in explosive mixtures of _fire-damp_ in coal mines, by consuming the fire-damp. _january , ._ . further experiments on the combustion of explosive mixtures confined by wire gauze, with some observations on flame. _january , ._ . some researches on flame. _january , ._ . some new experiments and observations on the combustion of gaseous mixtures; with an account of a method of preserving a continued light in mixtures of inflammable gases and air, without flame. _read january , ._ *** _for the preceding five papers, the rumford medals were awarded to him._ . on the fallacy of experiments in which water is said to have been formed by the decomposition of chlorine. _february , ._ . new experiments on some of the combinations of phosphorus. _april , ._ . some observations on the formation of mists in particular situations. _february , ._ . on the magnetic phenomena produced by electricity. _november , ._ . some observations and experiments on the papyri found in the ruins of herculaneum. _march , ._ . further researches on the magnetic phenomena produced by electricity; with some new experiments on the properties of electrified bodies, in their relations to conducting powers and temperature. _july , ._ . on the electrical phenomena exhibited _in vacuo_. _december , ._ . on the state of water and aëriform matter in cavities found in certain crystals. _read june , ._ . on a new phenomenon of electro-magnetism. _march , ._ . on the application of liquids formed by the condensation of gases, as mechanical agents. _april , ._ . on the changes of volume produced in gases, in different states of density, by heat. _may , ._ . on the corrosion of copper sheathing by sea-water; and on methods of preventing this effect, and on their application to ships of war and other ships. _jan. , ._ . additional experiments and observations on the application of electrical combinations to the preservation of the copper sheathing of ships, and to other purposes. _june , ._ . further researches on the preservation of metals by electro-chemical means. _june , ._ . the bakerian lecture for .--on the relation of electrical and chemical changes. _june , ._ **** _for this memoir, the royal society conferred upon him the royal medal._ . on the phenomena of volcanoes. _march , ._ . account of some experiments on the torpedo. _november , ._ his published works are, "experimental essays on heat, light, and on the combinations of light, with a new theory of respiration," &c. published in _contributions to physical and medical knowledge, by t. beddoes, m.d._ . "researches chemical and philosophical, chiefly concerning nitrous oxide, and its respiration." . "a syllabus of a course of lectures." "an introductory lecture." . "elements of chemical philosophy." . "elements of agricultural chemistry." . "on the safety lamp for coal miners; with some researches on flame." . (several editions.) "salmonia; or days of fly-fishing." "consolations in travel; or the last days of a philosopher." appendix. appendix. extracted from the registry of the prerogative court of canterbury. a. my will. this rd of january feeling more than usual symptoms of mortality i make this my will. first, i give my brother john davy m.d. three hundred pounds a-year of money that i possess in the long annuities and likewise four thousand pounds to be raised by the sale of securities i possess in the english or french funds or annuities but i mean my said brother to devote the interest of three thousand pound of these last moneys to such purposes as he may deem fitting for the benefit of my sisters particularly my married one and i wish a part of the interest of these three thousand pounds to be employed in educating and settling in life my godson humphrey millett. i leave him dr. davy likewise all the property devolving to me from my parents which has never been divided to do what seems to him best for the benefit of my sisters and my sister millett's children and i leave my said brother my chemical books and chemical mss. apparatus _sporting tackle_ medals and the silver venetian dish made from the rumford medal in token of my affection. i leave £ to each of these friends dr. babington and dr. franck and £ to dr. wilson philip and to mr. brodie surgeon to lay out in tokens of remembrance. i leave all my other property whether in goods money chattels funded securities annuities or plate to my wife (lady) jane davy and i appoint her the sole executrix of this my will. if my brother or his family should not be in a condition at the time of her decease to use my service of plate given for the safety lamp i wish it to be sold and the same given to the royal society to provide an annual medal from the interest for the best discovery made any where in chemistry and i depend upon my dear wife to make such presents in seals or token to such of my friends as she may think proper agreeably to their and her feelings. h. davy. b. further explanatory clause. i leave to my wife dame jane davy all my other property whether funded or in government securities or in leases of houses or goods &c. and i leave her my sole residuary legatee and sole executrix. i wish her to enjoy the use of my plate during her life and that she will leave it to my brother in case he survive her and if not to any child of his who may be capable of using it but if he be not in a situation to use or enjoy it then i wish it to be melted and given to the royal society to found a medal to be given annually for the most important discovery in chemistry any where made in europe or anglo-america. knowing the perfect understanding and love of justice of my wife i leave to her all other arrangements which may make my memory useful to the world and awaken the kind feelings of my friends and i wish her and my brother and all my friends every happiness this life can afford. humphry davy. c. that is a clause explanatory of my will. i wish seals not rings with a fish engraved upon them to be given to some of my friends amongst whom i mention mr knight dr babington mr pepys mr hatchett. and lest there should be any doubt respecting the £ mentioned i mean my brother to be a trustee for this and should he die without children i mean it to belong to my sister millett's children £ to humphry millett my godson and the rest to be equally divided between the other children but should my brother marry and have children i then mean after the death of my sisters these £ to be divided between her child or children and my sisters and £ to go to humphry millett my godson and £ to my sister's other children leaving the arrangement to my brother. h. d. d. further explanatory clause, feb. th . i leave to my brother john davy m.d. the proceeds of my agricultural chemistry in the future editions and the profits of my work on fishing and i give him the copyright. i leave my friend thomas poole esq. of stowey fifty pounds to purchase some token of remembrance. h. d. * * * * * rome nov. th, . by this addition to my will i confirm all that i have willed in a paper left in a brass box at messrs. drummond leaving lady davy my sole executrix and residuary legatee. i leave the copyright of salmonia to my brother john davy wishing him to apply a part of the profits of the sale of the editions of this work to the education of my nephew humphrey millett in case he has no children of his own. i leave the copy of my vision in my writing desk to lady davy to be published if my friends think it may give pleasure or information to the public but i wish the profits of this work to be applied to the use of my brothers and sisters. i leave to josephine detela daughter of mr. detela of laybach in illyria innkeeper my kind and affectionate nurse one hundred pounds or rather a sum which shall equal a thousand florins to be paid out of the balance at my banker's within three months after my decease. i beg lady davy to be so good as to fulfill my engagements with the persons who are travelling with me but without any favour as i have no reason to praise either their attention or civilities within the last two months but the kindness and attentions of josephine detela during my illness at laybach not only calls for the testimony i have given but likewise my gratitude for which i give her the £ or the florins. h. davy. * * * * * feb. th . i wish to be buried where i die _natura curat suas reliquias_. i wish £ to be given to george whidby and i beg lady davy to fulfill all my engagements and that if my friends should think my dialogues worthy of publication i beg that they may be published and that mr. tobin may correct the press of them and i wish that £ may be given to him for this labour. there is a codicil to my will in my writing desk. i beg lady davy to have the goodness to attend to every thing mentioned in that. in addition to what i have mentioned in that codicil i request that £ or florins may be given to josephine dettela within five months after my decease and i wish £ to be presented to my friend dr morichini in remembrance and memory of his great kindness to me. h. d. i wish one hundred to be given to my amanuensis. * * * * * for the purpose of explaining a will that i made before i left england and some papers that i have since added to it i write these few words rome, march , . i give the copyright of salmonia my dialogues and any other of my works which my friends may think it proper to republish to my brother john davy m.d. to be published in the manner he may think most fit and proper. i have already in my former testament left lady davy my residuary legatee but i beg her in considering the disposition of my property to regard £ as belonging to my brother dr. davy in case there rests any doubt upon this subject in my first will and i wish her the said lady davy to enjoy during her life the use and property of the different services of plate given to me whether by the emperor of russia or the different coal _committees_ but i trust to her sense of justice that she will leave them in the manner i have pointed out in my will to my brother. with respect to any property at present in my banker's hands or any thing i now carry with me i leave them entirely to my brother dr. davy. humphry davy. at rome march , . the end. london: printed by samuel bentley, dorset street, fleet street. transcriber's note: minor spelling and punctuation inconsistencies, and hyphenated words, have been harmonized. the formatting of the letters has been regularized. transcriber's note: this book was published in two volumes, of which this is the first. the second volume was released as project gutenberg ebook # , available at http:www.gutenberg.org/ebooks/ . italic text has been marked with _underscores_. please see the end of this project for further notes. [illustration] sir thos. lawrence pinxt. w. h. worthington sculpt. h. davy engraved by permission of the council of the royal society from the original painting. london, published by henry colburn & richard bentley . the life of sir humphry davy, bart. ll.d. late president of the royal society, foreign associate of the royal institute of france, &c. &c. &c. by john ayrton paris, m.d. cantab. f.r.s. &c. fellow of the royal college of physicians. in two volumes. vol. i. london: henry colburn and richard bentley, new burlington street. mdcccxxxi. london: printed by samuel bentley, dorset-street, fleet-street. to his royal highness prince augustus frederick, duke of sussex, k.g. d.c.l. _&c. &c. &c._ president of the royal society; these memoirs of a philosopher whose splendid discoveries illumined the age in which he lived, adorned the country which gave him birth, and obtained from foreign and hostile nations the homage of admiration and the meed of gratitude, are, by the gracious permission of his royal highness, dedicated with sentiments of profound respect, by the author. preface. the reflecting portion of mankind has ever felt desirous of becoming acquainted with the origin, progress, habits, and peculiarities of those whom the powers of genius may have raised above the plane of intellectual equality; but neither the nature of the information, nor the extent of the detail that may be necessary to satisfy so laudable a curiosity, can ever be estimated by any common standard, since it is not in our nature to contemplate an object of admiration, but with reference to our own predilections and sympathies; and hence every reader will form a scale for himself, according to the degree of interest he may feel for the particular character under review. the poetical enthusiast, who could not sufficiently express his gratitude on being told that milton wore shoe-buckles, would very probably not have given 'four farthings,' as gray says, to know that the shoes of davy were tanned by catechu; and yet if the relative value of this information were fairly estimated, it must be admitted that the former is a matter of barren curiosity, the latter, a fact of some practical utility. in a word, we very naturally connect the man with his works, and we care not to extend our acquaintance with the one, but in proportion as we have derived pleasure from the other. in like manner, very different estimates will be formed of the degree of praise due to a distinguished philosopher, because the few who are deeply imbued with a knowledge of the science he may have adorned and enlightened must not only appreciate the value of his labours, but understand the difficulties which opposed the accomplishment of them, before they can arrive at a sound decision upon the question: and here again the judgment of the most scientific may be unfortunately warped; it may be corrupted by secret passions or sinister influences; be distorted by the prejudices of education and habit, or unduly biassed by invincible prepossessions. no man ever soared, like an eagle, to the pinnacle of fame, without exciting the envy and perhaps the hatred of those who could only crawl up half-way; while, on the other hand, where no rivalry can exist, the splendour of such an ascent will captivate the bystander, and by exciting intemperate triumph and unqualified admiration, change without diminishing the sources of erroneous judgment, and substitute adulation for calumny. under such circumstances, an allusion even to the common frailties of genius becomes offensive; the biographer is called upon for the delineation of a perfect man; but the world is satisfied with nothing short of 'a faultless monster;' and yet, while they would impose upon him the same restraint as queen elizabeth laid upon her artist--to execute a portrait without a single shadow, they little imagine how completely they obscure the features of their idol, by the haze of incense in which they continually envelope it. these are evils against which a future historian will not have to contend; for time tries the characters of men, as the furnace assays the quality of metals, by disengaging the impurities, dissipating the superficial irridescence, and leaving the sterling gold bright and pure. nor can the extent of our obligations to a philosopher be appreciated until time shall have shown the various important purposes to which his discoveries may administer. the names of mayow and hales might have been lost in the stream of discovery, had not the results of priestley and lavoisier shown the value and importance of their statical experiments on the chemical relations of air to other substances. the discoveries of dr. black on the subject of _latent_ heat could never have obtained that celebrity they now enjoy, had not mr. watt availed himself of their application for the improvement of the steam-engine; and the views of sir h. davy respecting the true nature of chlorine become daily more important from the discovery of new elements of an analogous nature. in future ages, the metals of the alkalies and earths may admit of applications, and open new avenues of knowledge, of which at present we can form no idea; but it is obvious that, in the page of history, his name will gather fame in proportion as such discoveries unfold themselves. it must be admitted, that such considerations may furnish an argument against the propriety of writing the life of a contemporaneous philosopher; and yet i will never admit, with mr. babbage, that "the volume of his biography should be sealed, until the warm feelings of surviving kindred and admiring friends shall be cold as the grave, from which remembrance vainly recalls his cherished form, invested with all the life and energy of recent existence." is it not possible that the errors of partiality, which have so frequently been charged upon the writer on these occasions, may often be ascribed, with greater truth and justice, to the prejudices of the reader--that, after all, the distortion might not have existed in the portrait itself, but in the optics of the observer? such an opinion, however, even were it true, carries along with it no consolation to the biographer; for i know of no method by which the picture can be adapted to the focus of every eye. if, however, contemporaneous biography has its difficulties and impediments, so has it also its advantages. dr. johnson has remarked, in his life of addison, that "history may be formed from permanent monuments and records; but lives can only be written from personal knowledge, which is growing every day less, and in a short time is lost for ever. the delicate features of the mind, the nice discriminations of character, and the minute peculiarities of conduct, are soon obliterated." i did not enter upon this arduous and delicate task, without a distinct conception of the various difficulties which would necessarily oppose its accomplishment. i well knew that the biographer of davy must hold himself prepared for the dissatisfaction of one party at the commendations he might bestow, and for the displeasure of the other at the penury of his praise, or the asperity of his criticism. after great labour and much anxiety, i have at length completed the work; and in giving it to the world, i shall apply to myself the words of swift--"i have the ambition to wish, at least, that both parties may think me in the right; but if that is not to be hoped for, my next wish should be, that both might think me in the wrong, which i would understand as an ample justification of myself, and a sure ground to believe that i have proceeded, at least, with impartiality, and perhaps even with truth." it is certainly due to myself, and perhaps to the world, to state the circumstances by which i was induced to undertake a work requiring for its completion a freedom from anxiety, and an extent of research, scarcely compatible with the occupations of a laborious profession; and which, i may add, has been wholly composed during night, in hours stolen from sleep. very shortly after the death of sir humphry davy, an account of his life, written by no friendly hand, nor 'honest chronicler,' was submitted for my judgment by a journalist who had intended to insert it in his paper. at my request, it was committed to the flames; but not until i had promised to supply the loss by another memoir. the sketches by which i redeemed this pledge were published in a weekly journal--the spectator; and they have since been copied into various other works, sometimes with, but frequently without any acknowledgment. they constitute the greater part of the life which was printed in the annual obituary for ; and they form the introduction to an edition of his "last days," lately published in america. i was soon recognised as the writer of these sketches; and the leading publishers of the day urged me to undertake a more extended work. to these solicitations i returned a direct refusal: i even declined entering upon any conversation on the occasion; feeling that the wishes of lady davy, at that time on the continent, ought in the very first instance to be consulted on the subject. had not the common courtesy of society required such a mark of attention, the wish expressed by sir humphry in his will would have rendered it an imperative duty. on her arrival in london, in consequence of a letter she had addressed to mr. murray, i requested an interview with her ladyship, from whom i received not only an unqualified permission to become the biographer of her illustrious husband, but also the several documents which are published with acknowledgement in these memoirs. i still felt that dr. davy might desire to accomplish the task of recording the scientific services of his distinguished brother; and, had that been the case, i should most undoubtedly have retired without the least hesitation or reluctance; but i was assured by those who were best calculated to form an opinion upon this point,--for he was himself absent from england,--that motives of delicacy which it was easy to appreciate, would at once lead him to decline an undertaking embarrassed with so many personal considerations. the task, however, of collating the various works of sir h. davy, and of enriching them by notes derived from his own knowledge of the circumstances under which they were written, i do hope will be accomplished by one who is so well calculated to heighten the interest, and to increase the value of labours of such infinite importance to science, and to the best interests of mankind. the engraving which adorns the volume is from a painting by sir thomas lawrence, presented to the royal society by lady davy; and i beg the council of that learned body to accept my thanks for the permission they so readily granted for its being engraved. it is one of the happiest efforts of the distinguished artist, and is the only portrait i have seen in which his features are happily animated with the expression of the poet, and whose eye is bent to pursue the flights of his imagination through unexplored regions. i must also embrace this opportunity of publicly expressing my thanks to the managers of the royal institution, who, in the most handsome manner, immediately complied with my request to inspect their journals, and to make such extracts from them, as i might consider necessary for the completion of my memoirs. to mr. davies gilbert, i am under obligations which it is difficult for me to acknowledge in adequate terms, not only for the value of the materials with which he has furnished me, but for the kindness and urbanity with which they were communicated, and for the ready and powerful assistance which i have so constantly received from him during the progress of the work. to the other enlightened individuals from whom i have received support, i have acknowledged my obligations in the body of the work; and should i have inadvertently passed over any service without a becoming notice, i trust the extent of the labour and the circumstances under which it has been performed, will plead my apology. dover street, january , . contents. chapter i. birth and family of sir h. davy.--davy placed at a preparatory school.--his peculiarities when a boy.--anecdotes.--he is admitted into the grammar-school at penzance.--finishes his education under dr. cardew at truro.--death of his father.--he is apprenticed by his mother to mr. john bingham borlase, a surgeon and apothecary.--he enters upon the study of chemistry, and devotes more time to philosophy than to physic.--the influence of early impressions illustrated.--his poetical talent.--specimens of his versification.--an epic poem composed by him at the age of twelve years.--his first original experiment in chemistry.--he conceives a new theory of heat and light.--his ingenious experiment to demonstrate its truth.--he becomes known to mr. davies gilbert, the founder of his future fortunes.--mr. gregory watt arrives at penzance, and lodges in the house of mrs. davy.--the visit of dr. beddoes and professor hailstone to cornwall.--the correspondence between dr. beddoes and mr. davies gilbert, relative to the pneumatic institution at bristol, and the proposed appointment of davy.--his final departure from his native town page chapter ii. cursory thoughts on the advantages of biography.--plan and objects of the pneumatic institution.--davy contracts friendships during his residence at bristol.--his first visit to london.--his letters to mr. davies gilbert.--the publication of the west country contributions, by dr. beddoes.--davy's essays on heat, light, and respiration.--his interesting experiments on bonnet canes.--he commences an enquiry into the nature of nitrous oxyd.--he publishes his chemical researches.--a critical examination of the work.--testimony of tobin, clayfield, southey, and others, respecting the powers of nitrous oxyd.--davy breathes carburetted hydrogen gas, and nearly perishes from its effects.--his new galvanic experiments communicated in a letter to mr. gilbert chapter iii. count rumford negotiates with mr. underwood on the subject of davy's appointment to the royal institution.--terms of his engagement communicated in a letter to mr. gilbert.--davy arrives, and takes possession of his apartments.--he receives various mortifications.--he is elected a member of the tepidarian society.--is appointed lecturer instead of assistant.--he makes a tour in cornwall with mr. underwood.--anecdotes.--his poem on spinosism.--his letter to mr. gilbert, communicating a galvanic discovery.--he commences his first grand course of lectures.--his brilliant success.--a letter from mr. purkis.--davy's style criticised.--his extraordinary method of experimenting.--davy and wollaston compared as experimentalists.--the style of davy as a lecturer and a writer contrasted chapter iv. davy makes a tour with mr. purkis through wales.--beautiful phenomenon observed from the summit of arran benllyn.--letter to mr. gilbert.--journal of the institution.--davy's papers on eudiometry, and other subjects.--his first communication to the royal society, on a new galvanic pile.--he is proposed as a fellow, and elected into the society.--his paper on astringent vegetable substances, and on their operation in tanning leather.--his letter to mr. poole.--he is appointed chemical lecturer to the board of agriculture.--he forms friendships with the duke of bedford, mr. coke, and many other celebrated agriculturists.--attends the sheep-shearing at holkham and woburn.--composes a prologue to "the honey-moon" chapter v. sir thomas bernard allots davy a piece of ground for agricultural experiments.--history of the origin of the royal institution.--its early labours.--davy's letters to mr. gilbert and to mr. poole.--death of mr. gregory watt.--davy's passion for fishing, with anecdotes.--he makes a tour in ireland: his letters on the subject.--his paper on the analysis of the wavellite.--his memoirs on a new method of analysing minerals which contain a fixed alkali.--reflections on the discovery of galvanic electricity chapter vi. the history of galvanism divided into six grand epochs.--davy extends the experiment of nicholson and carlisle.--his pile of one metal and two fluids.--dr. wollaston advocates the doctrine of oxidation being the primary cause of voltaic phenomena.--davy's modification of that theory.--his bakerian lecture of .--he discovers the sources of the acid and alkaline matter eliminated from water by voltaic action.--on the nature of electrical decomposition and transfer.--on the relations between the electrical energies of bodies, and their chemical affinities.--general developement of the electro-chemical laws.--illustrations, applications, and conclusions chapter vii. the unfair rivalry of philosophers.--bonaparte the patron of science--he liberates dolomieu.--he founds a prize for the encouragement of electric researches.--his letter to the minister of the interior.--proceedings of the institute.--the prize is conferred on davy.--the bakerian lecture of .--the decomposition of the fixed alkalies--potassium--sodium.--the questions to which the discovery gave rise.--interesting extracts from the manuscript notes of the laboratory.--potash decomposed by a chemical process.--letters to children, and pepys.--the true nature of potash discovered.--whether ammonia contains oxygen.--davy's severe illness.--he recovers and resumes his labours.--his fishing costume.--he decomposes the earths.--important views to which the discovery has led chapter viii. davy's bakerian lecture of .--results obtained from the mutual action of potassium and ammonia upon each other.--his belief that he had decomposed nitrogen.--he discovers telluretted hydrogen.--whether sulphur, phosphorus, and carbon may not contain hydrogen.--he decomposes boracic acid.--boron.--his fallacies with regard to the composition of muriatic acid.--a splendid voltaic battery is constructed at the institution by subscription.--davy ascertains the true nature of the muriatic and oxymuriatic acids.--important chemical analogies to which the discovery gave origin.--euchlorine.--chlorides.--he delivers lectures before the dublin society.--he receives the honorary degree of ll.d. from the provost and fellows of trinity college.--he undertakes to ventilate the house of lords.--the regent confers upon him the honour of knighthood.--he delivers his farewell lecture.--engages in a gunpowder manufactory.--his marriage chapter ix. davy's "elements of chemical philosophy" examined.--his memoir on some combinations of phosphorus and sulphur, &c.--he discovers hydro-phosphoric gas.--important illustrations of the theory of definite proportionals.--bodies precipitated from water are hydrats.--his letter to sir joseph banks on a new detonating compound.--he is injured in the eye by its explosion.--his second letter on the subject.--his paper on the substances produced in different chemical processes on fluor spar.--his work on agricultural chemistry octr. {th} when potash was introduced into a tube having a platina wire attached to it so & fixed into the tube so as to be a conductor ie. so as to contain just water enough though solid--& inserted over mercury, when the platina was made neg--no gas was formed & the mercury became oxydated--& a small quantity of the athalyer was produced around the plat: wire as was evident from its gassy alteration by the action of water --when the mercury was made the neg: gas was developed in great quantities from the pos: wire, & some from the neg mercury & this gas proved to be pure? _oxygene_ capil expr.-- proving the decompr of _potash_ london, published by henry colburn & richard bentley [illustration] the life of sir humphry davy, bart. &c. &c. chapter i. birth and family of sir h. davy.--davy placed at a preparatory school.--his peculiarities when a boy.--anecdotes.--he is admitted into the grammar-school at penzance.--finishes his education under dr. cardew at truro.--death of his father.--he is apprenticed by his mother to mr. john bingham borlase, a surgeon and apothecary.--he enters upon the study of chemistry, and devotes more time to philosophy than to physic.--the influence of early impressions illustrated.--his poetical talent.--specimens of his versification.--an epic poem composed by him at the age of twelve years.--his first original experiment in chemistry.--he conceives a new theory of heat and light.--his ingenious experiment to demonstrate its truth.--he becomes known to mr. davies gilbert, the founder of his future fortunes.--mr. gregory watt arrives at penzance, and lodges in the house of mrs. davy.--the visit of dr. beddoes and professor hailstone to cornwall.--the correspondence between dr. beddoes and mr. davies gilbert, relative to the pneumatic institution at bristol, and the proposed appointment of davy.--his final departure from his native town. humphry davy was born at penzance, in cornwall, on the th of december .[ ] his ancestors had long possessed a small estate at varfell, in the parish of ludgvan, in the mount's bay, on which they resided: this appears from tablets in the church, one of which bears a date as far back as . we are, however, unable to ascend higher in the pedigree than to his paternal grandfather, who seems to have been a builder of considerable repute in the west of cornwall, and is said to have planned and erected the mansion of _trelissick_, near truro, at present the property and residence of thomas daniel, esq. [ ] i have been favoured by the rev. c. val. le grice, of trereiffe, with the following extract from the parish register, kept at madron:--"humphry davy, son of robert davy, baptized at penzance, january , ." the house in which he was born has been pulled down and lately rebuilt. his son, the parent of the illustrious subject of our history, was sent to london, and apprenticed to a carver in wood, but, on the death of his father, who, although originally a younger son, had latterly become the representative of the family, he found himself in the possession of a patrimony amply competent for the supply of his limited desires, and therefore pursued his art rather as an object of amusement than one of necessity: in the town and neighbourhood of penzance, however, there remain many specimens of his skill; and i have myself seen several chimney-pieces curiously embellished by his chisel.[ ] [ ] soon after the days of gibbons, the art of ornamental carving in wood began to decay, and it may now be considered as nearly lost. its decline may be attributed to two causes. in the first place, to the change of taste in fitting up the interior of our mansions; and in the next, to the introduction of composition for the enrichment of picture-frames and other objects of ornament. "robert davy," says a correspondent, "has been considered in this neighbourhood as the last of the carvers, and from his small size, was generally called _the little carver_." i am not able to discover that he was remarkable for any peculiarity of intellect; he passed through life without bustle, and quitted it with the usual regrets of friends and relatives. the habits, however, generally imputed to him were certainly not such as would have induced us to anticipate a high degree of steadiness in the son. his wife, whose maiden name was grace millett, was remarkable for the placidity of her temper, and for the amiable and benevolent tendency of her disposition: she had been adopted and brought up, together with her two sisters, under circumstances of affecting interest, by mr. john tonkin, an eminent surgeon and apothecary in penzance; a person of very considerable natural endowments, and whose socratic sayings are, to this day, proverbial with many of the older inhabitants. to withhold a narrative of the circumstances that led mr. tonkin to the adoption of these orphan children, would be a species of historical fraud and literary injustice, by which the world would not only lose one of those bright examples of pure and disinterested benevolence, which cheer the heart and ornament our nature, but the medical profession would be deprived of an additional claim to that public veneration and regard, to which the kind sympathy of its professors has so universally entitled it. the parents of these children, having been attacked by a fatal fever, expired within a few hours of each other: the dying agonies of the surviving mother were sharpened by her reflecting on the forlorn condition in which her children would be left; for, although the milletts were originally aristocratic and wealthy, the property had undergone so many subdivisions, as to have left but a very slender provision for the member of the family to whom she had united herself. the affecting appeal which mrs. millett is said to have addressed to her sympathising friend, and medical attendant, was not made in vain: on her decease, mr. tonkin immediately removed the three children to his own house, and they continued under the guardianship of their kind benefactor, until each, in succession, found a home by marriage. the eldest sister, jane, was married to henry sampson, a respectable watchmaker at penzance; the youngest, elizabeth, to her cousin, leonard millett of marazion; neither of whom had any family. the second sister, grace, was married to robert davy, from which union sprang five children, two boys and three girls, the eldest being humphry, the subject of our memoir, and the second son, john, now dr. davy, a surgeon to the forces, and a gentleman distinguished by several papers in the philosophical transactions. humphry davy was nursed by his mother, and passed his infancy with his parents;[ ] but his childhood, after they had removed from penzance to reside on their estate at varfell, was spent partly with them and partly with mr. john tonkin, who extended his disinterested kindness from the mother to all her children, but more especially to humphry, who is said, when a child, to have exhibited powers of mind superior to his years. i have spared no pains in collecting materials for the illustration of the earlier periods of his history; as, to estimate the magnitude of an object, we must measure the base with accuracy, in order to comprehend the elevation of its summit. [ ] for these materials i acknowledge myself indebted to dr. penneck of penzance, and to mrs. millett, sir h. davy's sister. the facts were communicated in letters to lady davy, by whom they were kindly placed at my disposal. he was first placed at a preparatory seminary kept by a mr. bushell, who was so struck with the progress he made, that he urged his father to remove him to a superior school. it is a fact worthy, perhaps, of being recorded, that he would at the age of about five years turn over the pages of a book as rapidly as if he were merely engaged in counting the number of leaves, or in hunting after pictures; and yet, on being questioned, he could generally give a very satisfactory account of the contents. i have been informed by lady davy that the same faculty was retained by him through life, and that she has often been astonished, beyond the power of expression, at the rapidity with which he read a work, and the accuracy with which he remembered it. mr. children has also communicated to me an anecdote, which may be related in illustration of the same quality. shortly after dr. murray had published his system of chemistry, davy accompanied mr. children in an excursion to tonbridge, and the new work was placed in the carriage. during the occasional intervals in which their conversation was suspended, davy was seen turning over the leaves of the book, but his companion did not believe it possible that he could have made himself acquainted with any part of its contents, until at the close of the journey he surprised him with a critical opinion of its merits. the book that engaged his earliest attention was "the pilgrim's progress," a production well calculated, from the exuberance of its invention, and the rich colouring of its fancy, for seizing upon the ardent imagination of youth. this pleasing work, it will be remembered, was the early and especial favourite of dr. franklin, who never alluded to it but with feelings of the most lively delight. shortly afterwards, he commenced reading history, particularly that of england; and at the age of eight years he would, as if impressed with the powers of oratory, collect together a number of boys in a circle, and mounting a cart or carriage that might be standing before the inn near mr. tonkin's house, harangue them on different subjects, and offer such comments as his own ideas might suggest. he was, moreover, at this age, a great lover of the marvellous, and amused himself and his schoolfellows by composing stories of romance and tales of chivalry, with all the fluency of an italian improvisatore; and joyfully would he have issued forth, armed _cap-à-pié_, in search of adventures, and to free the world of dragons and giants. in this early fondness for fiction, and in the habit of exercising his ingenuity in creating imagery for the gratification of his fancy, davy and sir walter scott greatly resembled each other. the author of waverley, in his general preface to the late edition of his novels, has given us the following account of this talent. "i must refer to a very early period of my life, were i to point out my first achievement as a tale-teller; but i believe most of my old schoolfellows can still bear witness that i had a distinguished character for that talent, at a time when the applause of my companions was my recompense for the disgraces and punishments which the future romance-writer incurred for being idle himself, and keeping others idle, during hours that should have been employed on our tasks." had not davy's talents been diverted into other channels, who can say that we might not have received from his inventive pen a series of romantic tales, as beautifully illustrative of the early history of his native country as are the waverley novels of that of scotland? for cornwall is by no means deficient in elfin sprites and busy "_piskeys_;" the invocation is alone required to summon them from their dark recesses and mystic abodes. davy was also in the frequent habit of writing verses and ballads; of making fireworks, and of preparing a particular detonating composition, to which he gave the name of "thunder-powder," and which he would explode on a stone to the great wonder and delight of his young playfellows. another of his favourite amusements may also be recorded in this place; for, however trifling in itself the incident may appear, to the biographer it is full of interest, as tending to show the early existence of that passion for experiment, which afterwards rose so nobly in its aims and objects, as the mind expanded with the advancement of his years. it consisted in scooping out the inside of a turnip, placing a lighted candle in the cavity, and then exhibiting it as a lamp; by the aid of which he would melt fragments of tin, obtained from the metallic blocks which commonly lie about the streets of a coinage town, and demand from his companions a certain number of pins for the privilege of witnessing the operation. at an early age, but i am unable to ascertain the exact period, he was placed at the grammar-school in penzance, under the rev. j. c. coryton; and whilst his father resided at varfell, he lived with mr. tonkin, except during the holidays, which he always spent with his parents. he was extremely fond of fishing; and i have been lately informed by one of his earliest companions, that when very young he greatly excelled in that art. "i have known him," says my correspondent, "catch grey-mullet at penzance pier, when none of us could succeed. the mullet is a very difficult fish to hook, on account of the diminutive size of its mouth; but davy adopted a plan of his own contrivance. observing that they always swam in shoals, he attached a succession of pilchards to a string, reaching from the surface to the bottom of the sea, and while his prey were swimming around the bait, he would by a sudden movement of the string entangle several of them on the hooks, and thus dexterously capture them." as soon as he became old enough to carry a gun, a portion of his leisure hours was passed in the recreation of shooting; a pursuit which also enabled him to form a collection of the rare birds which occasionally frequented the neighbourhood, and which he is said to have stuffed with more than ordinary skill. when at home, he frequently amused himself with reading and sketching, and sometimes with caricaturing any thing which struck his fancy; on some occasions he would shut himself up in his room, arrange the chairs, and lecture to them by the hour together. i have been informed by one of his schoolfellows, a gentleman now highly distinguished for his literary attainments, that, in addition to the amusements already noticed, he was very fond of playing at "tournament," fabricating shields and visors of pasteboard, and lances of wood, to which he gave the appearance of steel by means of black-lead. thus equipped, the juvenile combatants, like ascanius and the trojan youths of classic recollection, would tilt at each other, and perform a variety of warlike evolutions. by this anecdote we are forcibly reminded of the early taste of sir william jones, who, when a boy at harrow school, invented a political play, in which william bennet, bishop of cloyne, and the celebrated dr. parr, were his principal associates. they divided the fields in the neighbourhood of harrow, according to a map of greece, into states and kingdoms; each fixed upon one as his dominion, and assumed an ancient name. some of their schoolfellows consented to be styled barbarians, who were to invade their territories and attack their hillocks, which they denominated fortresses.[ ] [ ] life of sir william jones, by lord teignmouth. on one occasion, davy got up a pantomime; and i have very unexpectedly obtained a fly-leaf, torn out of a schrevelius' lexicon, on which the _dramatis personæ_, as well as the names of the young actors, were registered, as originally cast. this document appears so interesting, that i have thought it right to place it on record. _father_ cunnack. _harlequin_ davy. _clown_ ....[ ] _columbine_ hichens. _cupid_ veale. _fortuna_ scobell. _ben_ billy giddy. _nurse_ robyns. _maccaroni_ dennis. [ ] here, as mrs. ratcliffe would say, the legend is so effaced by damp and time, as to be wholly illegible. the performers, who, i believe, with one exception, are all living, will perhaps find some amusement in examining how far their future characters were shadowed forth on this occasion. at all events, i feel confident that they will receive no small gratification at having their recollections thus carried back to the joyous scenes of boyhood, connected as they always are, and must ever be, with the most delightful associations of our lives. from penzance school he went to truro, in the year , and finished his education under the rev. dr. cardew, a gentleman who is distinguished by the number of eminent scholars with which he has graced his country. that he was quick and industrious in his school exercises, may be inferred from an anecdote related by his sister, that "on being removed to truro, dr. cardew found him very deficient in the qualifications for the class of his age, but on observing the quickness of his talents, and his aptitude for learning, he did not place him in a lower form, telling him that by industry and attention he trusted he might be entitled to keep the place assigned to him; which," his sister says, "he did, to the entire satisfaction of his master." it is very natural that an anecdote so gratifying to the family should have been deeply imprinted on their memory; but we must not be surprised on finding that it did not make a similar impression upon dr. cardew. from a letter lately addressed by that gentleman to mr. davies gilbert, the following is an extract:--"with respect to our illustrious countryman, sir h. davy, i fear i can claim but little merit from the share i had in his education. he was not long with me; and while he remained i could not discern the faculties by which he was afterwards so much distinguished; i discovered, indeed, his taste for poetry, which i did not omit to encourage." dr. cardew adds, "while engaged in teaching the classics, i was anxious to discharge faithfully the duties of my profession to the best of my ability; but i was certainly fortunate in having so many good materials to work upon, and thus having only '_fungi vice cotis_,' though '_exsors ipse secandi_.'"--to the truth of this latter part of the doctor's quotation, will his scholars willingly subscribe? it may be fairly doubted how far dr. cardew was able to descend into the shadowy regions of maro, without the "_donum fatalis virgæ_." mrs. millett thinks that the deficiency just alluded to may be attributed to mr. coryton, rather than to the inattention of her brother; the former having, from his neglect as a master, given very general dissatisfaction. from what i can learn, at this distant period, of the character of mr. coryton, it appears at all events, that the "_exsors ipse secandi_" could not have been justly applied to him; and that, owing to an unfortunate aptness in the name to a doggrel verse, poor davy had frequently to smart under his tyranny. "now, master dàvy, now, sir, i hàve 'e, no one shall sàve 'e, good master dàvy;" when the master, suiting the action to the rhythm, inflicted upon the hand of the unlucky scholar the verberations of that type and instrument of pedagoguish authority--the flat ruler. here we have another example of the seduction of sound, argued by our great jurist mr. bentham,[ ] to have determined the maxims of that law, which has been pronounced by its sages the perfection of reason. [ ] "were the enquiry diligently made," he says, "it would be found that the goddess of harmony has exercised more influence, however latent, over the dispensations of themis, than her most diligent historiographers, or even her most passionate panegyrists, seem to be aware of. every one knows how, by the ministry of orpheus, it was she who first collected the sons of men beneath the shadow of the sceptre: yet in the midst of continual experience, men seem yet to learn with what successful diligence she laboured to guide it in its course." from a letter, however, written by davy a few years afterwards, respecting the education of a member of his family, he would appear to have entertained an opinion not very unlike that of john locke; for, although he testifies the highest respect for dr. cardew, he seems to consider the comparative idleness of his earlier school career, by allowing him to follow the bent of his own mind, to have favoured the developement of his peculiar genius. "after all," he says, "the way in which we are taught latin and greek, does not much influence the important structure of our minds. i consider it fortunate that i was left much to myself as a child, and put upon no particular plan of study, and that i enjoyed much idleness at mr. coryton's school. i perhaps owe to these circumstances the little talents i have, and their peculiar application:--what i am i have made myself--i say this without vanity, and in pure simplicity of heart." his temper during youth is represented as mild and amiable. he never suppressed his feelings, but every action was marked by ingenuousness and candour, qualities which endeared him to his youthful associates, and gained him the love of all who knew him. "nor can i find," says his sister, "beloved as he must have been by my mother, that she showed him any particular preference;--all her children appeared to be alike her care, and all alike shared her affection." in , mr. davy died. we cannot but regret that he did not live long enough to witness his son's eminence; for life, as johnson says, has few better things to give than a talented son; but from his widow, who has but lately descended to the tomb, full of years and respectability, this boon was not withheld, she witnessed his whole career of usefulness and honour, and happily closed her eyes before her maternal fears could have been awakened by those signs of premature decay, which for some time had excited in his friends, and in the friends of science, an alarm which the recent deplorable event has too fatally justified. in the year following the decease of her husband, mrs. davy, who had again taken up her residence in penzance, apprenticed her son,[ ] by the advice of her long-valued friend, mr. tonkin, to mr. john bingham borlase, at that time a surgeon and apothecary, but who afterwards obtained a diploma, and became an eminent physician at penzance. davy, however, for the most part, continued to pursue his own plans of study; for although his friend mr. tonkin, without doubt, intended him for a general practitioner in his native town, yet he himself always looked forward to graduation at edinburgh, as a preliminary measure to his practising in the higher walk of his profession. [ ] the original indenture, now in the possession of mr. r. edmonds, solicitor, of penzance, is dated february th, . his mind had, for some time, been engrossed with philosophical pursuits; but until after he had been placed with mr. borlase, it does not appear that he indicated any decided turn for chemistry, the study of which he then commenced with all the ardour of his temperament; and his eldest sister, who acted as his assistant, well remembers the ravages committed on her dress by corrosive substances. it has been said that his mind was first directed to chemistry by a desire to discover various mixtures as pigments: a suggestion to which, i confess, i am not disposed to pay much attention; for although he might have sought by new combinations to impart a novel and vivid richness of colouring to his drawings, it was the character of his mind to pursue with ardour every subject of novelty, and to get at results by his own native powers, rather than by the recorded experience of others. i must here relate an anecdote, in illustration of this statement, which has been lately communicated to me by the reverend dr. batten, the principal of the east india college at hayleybury. this gentleman was one of the earliest of davy's schoolfellows, but as he advanced in age, different views, and a different plan of education, carried him to a distant part of the kingdom; the discipline and duties of a cloistered school necessarily estranged him from his native town; and it was not until after his admission at cambridge, and the arrival of the long vacation, which afforded a temporary oblivion of academic cares, that mr. batten returned to cornwall, to revisit the scenes, and to renew the friendships of his boyish days. davy, who was at that period an apprentice to mr. borlase, received him with transport and affection; but he was no longer the boy that his friend had left him; he had become more serious and contemplative, fond of solitary rambles, and averse to enter into society, or to join the festive parties of the inhabitants. in fact, his mind was now in the act of being moulded by the spirit of nature; and, without the constraint of study, he was insensibly inhaling knowledge with the wild breezes of his native hills. in the course of conversation, mr. batten spoke of his academic studies; and in alluding to the principles of mechanics, to which he had lately paid much attention, he expressed himself more particularly pleased with that part which treats of "the collision of bodies." what was his surprise, on finding davy as well, if not better acquainted with its several propositions! it was true that he had never systematically studied the subject--had never perhaps seen any standard work upon it, but he had instituted experiments with elastic and inelastic balls, and had worked out the results by the unassisted energies of his own mind. it is clear that, had this branch of science not existed, davy would have created it. during this period of his apprenticeship, he twice a week attended a french school in penzance, kept by a m. dugast, a priest from la vendée; and it was remarked that, although he acquired a knowledge of the grammatical construction of the language with greater facility than any of the other scholars, he could not succeed in obtaining the pronunciation; and, in fact, notwithstanding his extensive intercourse with foreigners, and his residence in france, he never, even in after life, could pronounce french with correctness or speak it with fluency. while with mr. borlase, it was his constant custom to walk in the evening to marazion, to drink tea with an aunt to whom he was greatly attached. upon such occasions, his usual companion was a hammer, with which he procured specimens from the rocks on the beach. in short, it would appear that, at this period, he paid much more attention to philosophy than to physic; that he thought more of the bowels of the earth, than of the stomachs of his patients; and that, when he should have been bleeding the sick, he was opening veins in the granite. instead of preparing medicines in the surgery, he was experimenting in mr. tonkin's garret, which had now become the scene of his chemical operations; and, upon more than one occasion, it is said that he produced an explosion, which put the doctor, and all his glass bottles, in jeopardy. "this boy humphry is incorrigible!"--"was there ever so idle a dog!"--"he will blow us all into the air!" such were the constant exclamations of mr. tonkin; and then, in a jocose strain, he would speak of him as the "philosopher," and sometimes call him "sir humphry," as if prophetic of his future renown.[ ] [ ] davy appears to have been more fortunate than his prototype scheele; for on one occasion, as the latter was employed in making pyrophorus, a fellow apprentice, without his knowledge, put some fulminating powder into the mixture; the consequence was a violent explosion; the whole family was thrown into confusion, and the young chemist was severely chastised. his sister has remarked that, as he advanced in life, he always preferred the society of persons older than himself; and one of his contemporaries informs me that he never heard him allude to any subject of science, although he remembers that while one of his pockets was filled with fishing-tackle, the other was as commonly loaded with specimens of rocks. with those, however, who were superior to him in years, he delighted to enter into discussion. at penzance, there still resides a member of the society of friends, whose ingenuity entitles him to greater rewards than a provincial town can afford, with whom davy, as a boy, was in the constant habit of discussing questions of practical mechanics. "i tell thee what, humphry," exclaimed the quaker upon one of these occasions--"thou art the most quibbling hand at a dispute i ever met with in my life." for the surgical department of the profession, he always entertained a decided distaste, although the following extract from a letter of my correspondent mr. le grice will show that, for once at least, he had the merit of mending a broken head. "the first time i ever saw davy was on the battery rocks; we were alone bathing, and he pointed out to me a good place for diving; at the same time he talked about the tides, and sir isaac newton, in a manner that greatly amazed me. i perhaps should not have so distinctly remembered him, but on the following day, by not exactly marking the spot he had pointed out, i was nearly killed by diving on a rock, and he came as mr. borlase's assistant to dress the wound." it was his great delight to ramble along the sea-shore, and often, like the orator of athens, would he on such occasions declaim against the howling of the wind and waves, with a view to overcome a defect in his voice, which, although only slightly perceptible in his maturer age, was in the days of his boyhood exceedingly discordant. i may be allowed to observe, that the peculiar intonation he employed in his public addresses, and which rendered him obnoxious to the charge of affectation, was to be referred to a laborious effort to conceal this natural infirmity. it was also clear that he was deficient in that quality which is commonly called "a good ear," and with which the modulation of the voice is generally acknowledged to have an obvious connexion. those who knew him intimately will readily bear testimony to this fact. whenever he was deeply absorbed in a chemical research, it was his habit to hum some tune, if such it could be called, for it was impossible for any one to discover the air he intended to sing: indeed, davy's music became a subject of raillery amongst his friends; and mr. children informs me, that, during an excursion, they attempted to teach him the air of 'god save the king,' but their efforts were unavailing. it may be a question how far the following fact, with which i have just been made acquainted, admits of explanation upon this principle. on entering a volunteer infantry corps, commanded by a captain oxnam, davy could never emerge from the awkward squad; no pains could make him keep the step; and those who were so unfortunate as to stand before him in the ranks, ought to have been heroes invulnerable in the heel. this incapacity, as may be readily supposed, occasioned him considerable annoyance, and he engaged a serjeant to give him private lessons, but it was all to no purpose. in the platoon exercise he was not more expert; and he whose electric battery was destined to triumph over the animosity of nations, could never be taught to shoulder a musket in his native town. that davy, in his youth, possessed courage and decision, may be inferred from the circumstance of his having, upon receiving a bite from a dog supposed to be rabid, taken his pocket-knife, and without the least hesitation cut out the part on the spot, and then retired into the surgery and cauterized the wound; an operation which confined him to mr. tonkin's house for three weeks. the gentleman from whom i received an account of this adventure, the accuracy of which has been since confirmed by davy's sister, also told me, that he had frequently heard him declare his disbelief in the existence of pain whenever the energies of the mind were directed to counteract it; but he added, "i very shortly afterwards had an opportunity of witnessing a practical refutation of this doctrine in his own person; for upon being bitten by a conger eel, my young friend humphry roared out most lustily." the anecdote of davy's excising the bitten part with so much promptitude and coolness, derives its interest from the age and inexperience of the operator. in the course of his practice, every physician must have met with similar cases of stern decision; but i will venture to say that they have never occurred except in instances of persons of acknowledged courage. not many days since, a veteran officer, distinguished for the intrepidity with which he rescued the person of george the third from the fury of a desperate mob, in st. james's park, informed me that he had formerly been bitten at vienna by a dog afterwards ascertained to have been rabid; he immediately entered a blacksmith's shop, and by threats compelled the person at the forge to heat an iron red-hot, and burn his leg to the bone. the blacksmith, after first stipulating that he should strap his eccentric customer to the anvil, reluctantly complied; and my friend showed me a scar which sufficiently testified the complete manner in which the son of vulcan had performed his engagement:--but to return from this digression. at this time of day, no one can surely believe with pope, that a "ruling passion" is an innate and irresistible affection antecedent to reason and observation: on the contrary, ample experience has led us to the conclusion, that ----"men's judgments are a parcel of their fortunes, and things outward do draw the inward quality after them." the prevailing bias of great minds may thus be often traced to some accidental, and apparently trivial, impression in early life; and the acute biographer, in the course of his observations, will continually discover traits of character that are readily referable to such a source, even as in the magical colouring of rembrandt's works, the practised eye will recognize the _chiaro-oscuro_ of his father's mill, in which the artist passed his hours of childhood. in like manner, that marked aversion to arbitrary power, which ever distinguished the actions and writings of dr. franklin, has by himself been referred to the sense of injustice early imprinted upon his mind by the severe and tyrannical conduct of his elder brother; while, at the same time, he tells us that he was indebted for his habit through life, of forming just estimates of the value of things, to his having, at the age of seven years, "paid too much for his whistle." but circumstances, however disposed and happily combined, although they may direct, can never create genius; it is possible that cowley might never have been enamoured of the muses, nor sir joshua reynolds have courted the graces, but for the casual circumstances recorded by the biographer; and ferguson might not have turned his attention to mechanical inventions, had not an accident befallen the roof of his father's cottage; and even priestley, the founder of a new and beautiful department in science, might very probably never have been led to think of pneumatic chemistry, had he not lived in the vicinity of a great brewery: still, however, such men could not have shone dimly, if true genius be correctly defined by dr. johnson as "a mind of large general powers accidentally determined to some particular direction."[ ]--so with davy; his mind was as vigorous as it was original, and no less logical and precise than it was daring and comprehensive; nothing was too mighty for its grasp, nothing too minute for its observation; like the trunk of the elephant, it could tear up the oak of the forest, or gently pluck the acorn from its branch. [ ] m. de bourrienne, in his "private memoirs of napoleon buonaparte," appears to have justly appreciated the influence of circumstances upon the destinies of great men. in speaking of buonaparte at the military college of brienne, he says, "if the monks, to whom the superintendence of the establishment was confided, had engaged more able mathematical professors, or if we had had any excitement to the study of chemistry, or natural philosophy, i am convinced that buonaparte would have pursued those sciences with all the genius and spirit of investigation, which he displayed in a career more brilliant, it is true, but far less useful to mankind." that circumstances in early life should have directed such energies to a science, which requires for its advancement all the aids of novel and bold, and yet patient and accurate research, is one of those fortunate events which every unprejudiced mind will view with triumph. it is surely not difficult to understand how it happened that a mind endowed with the genius and sensibilities of davy, should have been directed to the study of chemistry and mineralogy, when we consider the nature and scenery of the country in which accident had placed him. many of his friends and associates must have been connected with mining speculations: "shafts," "cross courses," and "lodes," were words familiarised to his ears; and his native love of enquiry could not have long suffered them to remain strangers to his understanding. nor could he have wandered along the rocky coast, or have reposed for a moment to contemplate its wild scenery, without being invited to geological enquiry by the genius of the place; for were we to personify the science, where could we find a more appropriate spot for her "local habitation?" "how often when a boy," said davy to me, on my showing him a drawing of the wild rock scenery of botallack mine, "have i wandered about those rocks in search of new minerals, and, when fatigued, sat down upon the turf, and exercised my fancy in anticipations of scientific renown!" such scenery, also, in one who possessed a quick sensibility to the sublime forms of nature, was well calculated to kindle that enthusiasm which is so essential to poetical genius; and we accordingly learn, that he became enamoured of the muses at a very early age, and evinced his passion by several poetical productions. i am assured by dr. batten that, at the age of twelve years, he had finished an epic poem, which he entitled the "tydidiad," from its celebrating the adventures of diomede on his return from the trojan war. it is much to be regretted that not even a fragment of this poem should have been preserved; but dr. batten well remembers that it was characterised by great freedom of invention, vigour of description, and wildness of execution. at the age of seventeen he became desperately enamoured of a young french lady, at that time resident at penzance, to whom he addressed numerous sonnets; but these, like the passion that produced them, have long since been extinct. several of his minor productions were printed in a work entitled the "annual anthology," published in three volumes at bristol, in ; two of which were edited by southey, and one by james tobin;--a work of some curiosity, independent of its merits, as the first attempt in this country to establish an "annual," a species of literary composition which has lately been made very popular and amusing. these volumes have now become extremely scarce, for which, and other reasons, i have thought it right to place davy's productions on record in these memoirs; for although they are marked by the common faults of youthful poets, they still bear the stamp of lofty genius. there is, besides, a vein of philosophical contemplation running through their composition, which may be considered as indicating the future character and pursuit of their author; an ardent aspiration after fame seems, even at this early period, to have been felt in all its force, and is expressed in many striking and beautiful passages. there is still a higher motive by which i am induced to introduce these specimens into my memoir, that of showing the bias of his genius at this early period, with a view to compare it with that which displayed itself in the "last days of the philosopher." we shall find that the bright and rosy hues of fancy which gilded the morning of his life, and were subdued or chased away by the more resplendent light of maturer age, again glowed forth in the evening of his days, and illumined the setting, as they had the dawning of his genius. his first production bears the date of , and is entitled the sons of genius. bright bursting through the awful veil of night the lunar beams upon the ocean play, the watery billows shine with trembling light, where the swift breezes skim along the sea. the glimmering stars in yon ethereal plain grow pale, and fade before the lucid beams, save where fair venus, shining o'er the main conspicuous, still with fainter radiance gleams. clear is the azure firmament above, save where the white cloud floats upon the breeze, all tranquil is the bosom of the grove, save where the zephyr warbles through the trees. now the poor shepherd wandering to his home surveys the darkening scene with fearful eye, on every green sees little elfins roam, and haggard sprites along the moonbeams fly. while superstition rules the vulgar soul, forbids the energies of man to rise, raised far above her low, her mean controul, aspiring genius seeks her native skies. she loves the silent solitary hours, she loves the stillness of the starry night, when o'er the brightening view selene pours the soft effulgence of her pensive light. 'tis then disturb'd not by the glare of day; to mild tranquillity alone resign'd, reason extends her animating sway o'er the calm empire of the peaceful mind. before her lucid, all-enlightening ray, the pallid spectres of the night retire, she drives the gloomy terrors far away, and fills the bosom with celestial fire. inspired by her, the sons of genius rise above all earthly thoughts, all vulgar care; wealth, power, and grandeur they alike despise, enraptured by the good, the great, the fair. a thousand varying joys to them belong-- the charms of nature and her changeful scenes; their's is the music of the vernal song, and their's the colours of the vernal plains. their's is the purple-tinged evening ray, with all the radiance of the morning sky; their's is the splendour of the risen day, enshrined in glory by the sun's bright eye. for them the zephyr fans the odorous gale, for them the warbling streamlet softly flows, for them the dryads shade the verdant vale, to them sweet philomel attunes her woes. to them no wakeful moonbeam shines in vain on the dark bosom of the trackless wood, sheds its mild radiance o'er the desert plain, or softly glides along the chrystal flood. yet not alone delight the soft and fair, alike the grander scenes of nature move; yet not alone her beauties claim their care, the great, sublime, and terrible, they love. the sons of nature, they alike delight in the rough precipice's broken steep, in the black terrors of the stormy night, and in the thunders of the threatening deep. when the red lightnings through the ether fly, and the white foaming billows lash the shores; when to the rattling thunders of the sky the angry demon of the waters roars; and when, untouch'd by nature's living fires, no native rapture fills the drowsy soul; then former ages, with their tuneful lyres, can bid the fury of the passions fall. by the blue taper's melancholy light, whilst all around the midnight torrents pour, and awful glooms beset the face of night, they wear the silent solitary hour. ah, then, how sweet to pass the night away in silent converse with the grecian page! whilst homer tunes his ever-living lay, or reason listens to th' athenian sage; to scan the laws of nature, to explore the tranquil reign of mild philosophy; or on newtonian wings sublime to soar through the bright regions of the starry sky. ah! who can paint what raptures fill the soul when attic freedom rises to the war, bids the loud thunders of the battle roll, and drives the tyrant trembling from her shore! from these pursuits the sons of genius scan the end of their creation; hence they know the fair, sublime, immortal hopes of man, from whence alone undying pleasures glow. by science calm'd, over the peaceful soul, bright with eternal wisdom's lucid ray, peace, meek of eye, extends her soft controul, and drives the fury passions far away. virtue, the daughter of the skies supreme, directs their life, informs their glowing lays-- a steady friend; her animating beam sheds its soft lustre o'er their latter days. when life's warm fountains feel the frost of time; when the cold dews of darkness close their eyes, she shows the parting soul, upraised sublime, the brighter glories of her kindred skies. thus the pale moon, whose pure celestial light has chased the gloomy clouds of heaven away, rests her white cheek, with silver radiance bright, on the soft bosom of the western sea. lost in the glowing wave, her radiance dies; yet, while she sinks, she points her ling'ring ray to the bright azure of the orient skies-- to the fair dawning of the glorious day. like the tumultuous billows of the sea succeed the generations of mankind; some in oblivious silence pass away, and leave no vestige of their lives behind. others, like those proud waves which beat the shore, a loud and momentary murmur raise; but soon their transient glories are no more,-- no future ages echo with their praise. like yon proud rocks amidst the sea of time, superior, scorning all the billows' rage, the living sons of genius stand sublime, th' immortal children of another age. for those exist whose pure ethereal minds, imbibing portions of celestial day, scorn all terrestrial cares, all mean designs, as bright-eyed eagles scorn the lunar ray. their's is the glory of a lasting name, the meed of genius and her living fires, their's is the laurel of eternal fame, and their's the sweetness of the muse's lyres. d.-- . the song of pleasure. the genial influence of the day had chased the lingering cold away; borne upon the zephyr's wing, sweetly smiled the radiant spring: her mild re-animating breath wakes nature from her wintry death; attended by the laughing hours, she rises clad in flowers, and lightly as she trips along, the vernal warblers raise the song. rich in a thousand radiant dyes, around her steps the flow'rets rise, the zephyr sports, the sunbeams sleep on the blue bosom of the deep. and now, within my throbbing breast i feel the influence of the spring, to ecstasy i tune my string, and garlanded with odorous flowers, i hasted to the shady grove, i hasted to the roseate bowers where pleasure dwells with love. there youth, and love, and beauty, bound the glowing rose my harp around; then to the daughter of desire, to bright-eyed pleasure gave the lyre: she tuned the string, and smiling softer than the rosy sea, when the young morning blushes on her breast, she raised the raptured lay, i heard her sing, the song lull'd every care and every thought to rest. sons of nature, hither haste, the blessings of existence taste; listen to my friendly lay, and your cares shall fly away, quick as fly the wintry snows when the vernal zephyr blows. let others, courting war's alarms, seek the bloody field of arms; let others, with undaunted soul, bid bellona's thunders roll; from the lightnings of their eye let the trembling squadrons fly; sons of nature, you shall prove a softer fight, the fight of love. while you in soft repose are laid underneath the myrtle shade, amid the murky glooms of death, the sons of battle pant for breath. let the philosophic sage, his silver tresses white with age, amid the chilling midnight damp, waste the solitary lamp, to scan the laws of nature o'er, the paths of science to explore; curb'd beneath his harsh controul the blissful passions fly the soul. you, the gentler sons of joy, softer studies shall employ! he to curb the passions tries, you shall bid them all arise; his wants he wishes to destroy, you shall all your wants enjoy. let the laurel, virtue's meed, crown his age-besilver'd head, the verdant laurel ever grows amid the sullen winter's snows: let the rose, the flower of bliss, the soft unwrinkled temples kiss; fann'd by the zephyr's balmy wing, the odorous rose adorns the spring. let the patriot die, to raise a lasting monument of praise. ah, fool, to tear the glowing rose from the mirth-encircled brows, that around his dusky tomb the ever-verdant bay may bloom! let ambition's sons alone bow around the tottering throne, fly at glory's splendid rays, and, moth-like, die amidst a blaze; you shall bow, and bow alone, before delicious beauty's throne. lo! theora treads the green, all breathing grace and harmony she moves, fair as the mother of the loves. in graceful ringlets floats her golden hair; from the bright azure of her eye expression's liquid lightnings fly. her cheek is fair, fair as the lily, when, at dawning day, tinged with the morning's bright and purple ray, yonder scented groves among she will listen to your song. in yonder bower where roses bloom, where the myrtle breathes perfume, you shall at your ease recline, and sip the soul-enlivening wine; there the lyre, with melting lay, shall bid the soul dissolve away. soft as the morning sheds her purple light through the dark azure of the night, so soft the god of slumber sheds his roseate dews around your heads. such the blessings i bestow! haste, my sons, these blessings know! behold the flow'rets of the spring, they wanton in the zephyr's wing, they drink the matin ether blue, they sip the fragrant evening dew. man is but a short-lived flower, his bloom but for a changeful hour! pass a little time away, the rosy cheek is turn'd to clay: no living joys, no transports burn in the dark sepulchral urn, no _laurels_ crown the fleshless brows, they fade together with the _rose_. d.-- . ode to saint michael's mount, in cornwall. the sober eve with purple bright sheds o'er the hills her tranquil light in many a lingering ray; the radiance trembles on the deep, where rises rough thy rugged steep, old michael, from the sea. around thy base, in azure pride, flows the silver-crested tide, in gently winding waves; the zephyr creeps thy cliffs around,-- thy cliffs, with whispering ivy crown'd, and murmurs in thy caves. majestic steep! ah, yet i love, with many a lingering step, to rove thy ivied rocks among; thy ivied, wave-beat rocks recall the former pleasures of my soul, when life was gay and young. enthusiasm, nature's child, here sung to me her wood-songs wild, all warm with native fire; i felt her soul-awakening flame, it bade my bosom burn for fame,-- it bade me strike the lyre. soft as the morning sheds her light through the dark azure of the night along the tranquil sea; so soft the bright-eyed fancy shed her rapturing dreams around my head, and drove my cares away. when the white moon with glory crown'd, the azure of the sky around, her silver radiance shed; when shone the waves with trembling light, and slept the lustre palely bright upon thy tower-clad head; then beauty bade my pleasure flow,-- then beauty bade my bosom glow, with mild and gentle fire! then mirth, and cheerfulness, and love, around my soul were wont to move, and thrill'd upon my lyre. but when the demon of the deep howl'd around thy rocky steep, and bade the tempests rise,-- bade the white foaming billows roar, and murmuring dash the rocky shore, and mingle with the skies; ah, then my soul was raised on high, and felt the glow of ecstasy, with _great_ emotions fill'd; thus joy and terror reign'd by turns, and now with love the bosom burns, and now by fear is chill'd. thus to the sweetest dreams resign'd, the fairy fancy ruled my mind, and shone upon my youth; but now, to awful reason given, i leave her dear ideal heaven to hear the voice of truth. she claims my best, my loftiest song, she leads a brighter maid along-- divine philosophy, who bids the mounting soul assume immortal wisdom's eagle plume, and penetrating eye, above delusion's dusky maze, above deceitful fancy's ways, with roses clad to rise; to view a gleam of purest light bursting through nature's misty night,-- the radiance of the skies. d.-- . the tempest. the tempest has darken'd the face of the skies, the winds whistle wildly across the waste plain, the fiends of the whirlwind terrific arise, and mingle the clouds with the white-foaming main. all dark is the night, and all gloomy the shore, save when the red lightnings the ether divide, then follows the thunder with loud-sounding roar, and echoes in concert the billowy tide. but though now all is murky and shaded with gloom, hope, the soother, soft whispers the tempests shall cease; then nature again in her beauty shall bloom, and enamour'd embrace the fair sweet-smiling peace; for the bright-blushing morning, all rosy with light, shall convey on her wings the creator of day; he shall drive all the tempests and terrors of night, and nature enliven'd, again shall be gay. then the warblers of spring shall attune the soft lay, and again the bright flow'ret shall blush in the vale; on the breast of the ocean the zephyr shall play, and the sunbeam shall sleep on the hill and the dale. if the tempests of nature so soon sink to rest-- if her once-faded beauties so soon glow again, shall man be for ever by tempests oppress'd, by the tempests of passion, of sorrow, and pain? ah, no! for his passions and sorrow shall cease when the troublesome fever of life shall be o'er; in the night of the grave he shall slumber in peace, and passion and sorrow shall vex him no more. and shall not this night and its long dismal gloom, like the night of the tempest, again pass away? yes! the dust of the earth in bright beauty shall bloom, and rise to the morning of heavenly day! d.-- . extract from an unfinished poem on mount's bay. mild blows the zephyr o'er the ocean dark, the zephyr wafting the grey twilight clouds across the waves, to drink the solar rays and blush with purple. by the orient gleam whitening the foam of the blue wave that breaks around his granite feet, but dimly seen, majestic michael rises. he whose brow is crown'd with castles, and whose rocky sides are clad with dusky ivy: he whose base, beat by the storm of ages, stands unmoved amidst the wreck of things, the change of time. that base encircled by the azure waves, was once with verdure clad: the tow'ring oaks there waved their branches green,--the sacred oaks whose awful shades among, the druids stray'd to cut the hallow'd miseltoe, and hold high converse with their gods. on yon rough crag, where the wild tamarisk whistles to the sea blast, the druid's harp was heard, swept by the breeze to softest music, or to grander tones awaken'd by the awful master's hand. those tones shall sound no more! the rushing waves, raised from the vast atlantic, have o'erwhelm'd the sacred groves. and deep the druids lie in the dark mist-clad sea of former time. ages had pass'd away, the stony altar was white with moss, when on its rugged base dire superstition raised the gothic fane, and monks and priests existed. on the sea the sunbeams tremble; and the purple light illumes the dark bolerium,[ ] seat of storms. high are his granite rocks. his frowning brow hangs o'er the smiling ocean. in his caves th' atlantic breezes murmur. in his caves, where sleep the haggard spirits of the storm, wild dreary are the _schistine_[ ] rocks around encircled by the wave, where to the breeze the haggard cormorant shrieks. and far beyond are seen the cloud-like islands, grey in mists.[ ] thy awful height, bolerium, is not loved by busy man, and no one wanders there save he who follows nature,--he who seeks amidst thy crags and storm-beat rocks to find the marks of changes teaching the great laws that raised the globe from chaos; or he whose soul is warm with fire poetic,--he who feels when nature smiles in beauty, or sublime rises in majesty,--he who can stand unawed upon thy summit, clad in tempests, and view with raptured mind the roaring deep rise o'er thy foam-clad base, while the black cloud bursts with the fire of heaven-- he whose heart is warm with love and mercy,--he whose eye drops the bright tear when anxious fancy paints upon his mind the image of the maid, the blue-eyed maid who died beneath thy surge. where yon dark cliff[ ] o'ershadows the blue main, theora died amidst the stormy waves, and on its feet the sea-dews wash'd her corpse, and the wild breath of storms shook her black locks. young was theora; bluer was her eye than the bright azure of the moonlight night; fair was her cheek as is the ocean cloud red with the morning ray. amidst the groves, and greens, and nodding rocks that overhang the grey killarney, pass'd her morning days bright with the beams of joy. to solitude, to nature, and to god, she gave her youth; hence were her passions tuned to harmony. her azure eye oft glisten'd with the tear of sensibility, and her soft cheek glow'd with the blush of rapture. hence, she loved to wander 'midst the green-wood, silver'd o'er by the bright moonbeam. hence, she loved the rocks crown'd with the nodding ivy, and the lake fair with the purple morning, and the sea expansive mingling with the arched sky. kindled by genius, in her bosom glow'd the sacred fire of freedom. hence, she scorn'd the narrow laws of custom that control her feeble sex. great in her energies, she roam'd the fields of nature, scann'd the laws that move the ruling atoms, changing still, still rising into life. her eagle eye, piercing the blue immensity of space, held converse with the lucid sons of heaven, the day-stars of creation, or pursued the dusky planets rolling round the sun, and drinking in his radiance light and life. such was the maiden! such was she who fled her native shores. dark in the midnight cloud, when the wild blast upon its pinions bore the dying shrieks of erin's injured sons,[ ] she 'scaped the murderer's arm. the british bark bore her across the ocean. from the west the whirlwind rose, the fire-fraught clouds of heaven were mingled with the wave. the shatter'd bark sunk at thy feet, bolerium, and the white surge closed on green erin's daughter. [ ] the land's end in cornwall. [ ] the granite of cornwall is generally found incumbent on primitive _schistus_. this is the case in many of the cliffs at the land's end. the upper stratum is composed of granite, the lower with the surrounding rocks of _schistus_. d. [ ] the islands of scilly. [ ] a rock near the land's end, called the 'irish lady.' [ ] the irish lady was shipwrecked at the land's end, about the time of the massacre of the irish protestants by the catholics, in the reign of charles the first. that the genius who presided over the destinies of davy should have torn him from these flowery regions of fancy, and condemned him to labour in the dusky caverns of the mineral kingdom, has furnished a fruitful theme of lamentation to the band of poets, and to those who prefer the amusements to the profits of life, and who cherish the hallucinations of the imagination rather than the truths of science. if, however, we regret that davy's muse, like proserpine, should have been thus violently seized, and carried off to the lower regions, as she was weaving her native wild flowers into a garland, we may console ourselves in knowing that, like the daughter of ceres, she also obtained the privilege of occasionally revisiting her native bowers; for it will appear in the course of these memoirs, that in the intervals of more abstruse studies, davy not unfrequently amused himself with poetical composition. but, in sober truth, is it possible that any reasonable being can regret the course in which he has been impelled? a great poetic genius has said, "if davy had not been the first chemist, he would have been the first poet of his age." upon this question i do not feel myself a competent judge: but where is the modern esau who would exchange his bakerian lecture for a poem, though it should equal in design and execution the paradise lost? as far as can be ascertained, one of the first original experiments in chemistry performed by him at penzance, was for the purpose of discovering the quality of the air contained in the bladders of sea-weed, in order to obtain results in support of a favourite theory of light; and to ascertain whether, as land vegetables are the renovators of the atmosphere of land-animals, sea-vegetables might not be the preservers of the equilibrium of the atmosphere of the ocean. from these experiments he concluded, that the different orders of the marine _cryptogamia_ were capable of decomposing water, when assisted by the attraction of light for oxygen. his instruments, however, were of the rudest description, manufactured by himself out of the motley materials which chance threw in his way; the pots and pans of the kitchen, and even the more sacred vessels and professional instruments of the surgery, were without the least hesitation or remorse put in requisition. while upon this subject, i will relate an anecdote which was communicated to me by my late venerable friend mr. thomas giddy.[ ] a french vessel having been wrecked off the land's end, the surgeon escaped, and found his way to penzance; accident brought him acquainted with humphry davy, who showed him many civilities, and in return received, as a present from the surgeon, a case of instruments which had been saved from the ship. the contents were eagerly turned out and examined by the young chemist, not, however, with any professional view as to their utility, but in order to ascertain how far they might be convertible to experimental purposes. the old-fashioned and clumsy glyster apparatus was viewed with exultation, and seized in triumph!--what reverses may not be suddenly effected by a simple accident! so says the moralist. reader, behold an illustration:--in the brief space of an hour, did this long-neglected and unobtrusive machine, emerging from its obscurity and insignificance, figure away in all the pomp and glory of a complicated piece of pneumatic apparatus: nor did its fortunes end here; it was destined for greater things; and we shall hereafter learn that it actually performed the duties of an air-pump, in an original experiment on the nature and sources of heat. the most humble means may certainly accomplish the highest ends: the filament of a spider's web has been used to measure the motions of the stars; and a kite, made with two cross sticks and a silk handkerchief, enabled the chemical prometheus to rob the thunder-cloud of its lightnings; but that a worn-out instrument, such as has been just described, should have furnished him who was born to revolutionize the science of the age, with the only means of enquiry at that time within his reach, affords, it must be admitted, a very whimsical illustration of our maxim. [ ] i cannot allude to this name, without paying a tribute of respect to the memory of one who, for more than half a century, practised the profession of a surgeon in penzance with as much credit to himself, as advantage to his neighbourhood. nor can we pass over these circumstances, without observing how materially they must have influenced the subsequent success of davy as an experimentalist. had he, at the commencement of his career, been furnished with all those appliances which he enjoyed at a later period, it is more than probable that he might never have acquired that wonderful tact of manipulation, that ability of suggesting expedients, and of contriving apparatus so as to meet and surmount the difficulties which must ever beset the philosopher in the unbeaten tracks of science. in this art, he certainly stands unrivalled, and, like his prototype scheele,[ ] or that pioneer of pneumatic experimentalists, dr. priestley,[ ] he was unquestionably indebted for his address to the circumstances above related. there never, perhaps, was a more striking exemplification of the adage, that "necessity is the parent of invention." [ ] bergman, professor of upsal, was informed of a young man who resided in the house of an apothecary, and who was reproached for neglecting the duties of his profession, while he devoted the whole of his time to chemistry. bergman's curiosity was excited; he paid him a visit, and was astonished at the knowledge he displayed, and at the profound researches in which he was engaged, notwithstanding the poverty under which he laboured, and the restraint under which his situation placed him. he encouraged his ardour, and made him his friend. this young man was the celebrated _scheele_. [ ] no man ever entered upon an undertaking with less apparent means of success, than did priestley upon that of chemistry. he neither possessed apparatus, nor the money to procure it. these circumstances, which at first sight seem so adverse, were in reality those which contributed to his ultimate success. the branch of chemistry he selected was new; an apparatus had to be invented before any important step could be taken; and as simplicity is essential in every research, he was likely to contrive the best whose circumstances obliged him to attend to economy. it would however appear that, imperfect as must have been his apparatus, and limited as were his resources, his ambition very early led him to the investigation of the most abstruse and recondite phenomena. he was not more than seventeen when he formed a strong opinion adverse to the general belief in the existence of _caloric_, or the materiality of heat. as i shall hereafter have occasion to draw a parallel between the intellectual qualities of davy, and those of the celebrated dr. black, the father of modern chemistry, it may not be irrelevant to state, in this place, that the subject of heat was also amongst the first that attracted the attention of this latter philosopher; indeed, he tells us himself, that he "can scarcely remember the time, when he had not some idea of the disagreement of facts with the commonly received doctrines upon this subject." the tendency of his mind, however, was in direct opposition to that of davy's, for he insisted upon the materiality of heat, and was the first to conceive the bold idea of its being capable, like any other substance, of entering into chemical combination with various bodies, and of thus losing its characteristic qualities. black's theory could not be more opposed to that of davy than was his conduct upon the occasion; for, although an experiment suggested itself to his mind, by which, as he thought, he could at once establish the truth of his favourite doctrine, he delayed performing it, because there did not happen to be an ice-house in the town in which he lived. with davy, on the other hand, the conception and execution of an experiment were nearly simultaneous: no sooner, therefore, had he formed his opinion, than his eager spirit urged him to put it to the test. having procured a piece of clock-work, so contrived as to be set to work in an exhausted receiver, he added two horizontal plates of brass; the upper one, carrying a small metallic cup to be filled with ice, revolved in contact with the lower one. the whole machine, resting on a plate of ice, was covered by a glass receiver, and the air was exhausted by the very syringe, ingeniously modified for the purpose, with which the reader has already been made acquainted: for, as yet, he had no air-pump, and, what is still more worthy of notice, had never even seen one! the machine was now set in motion, when the ice in the small cup was soon observed to melt; whence he inferred that this effect could alone proceed from vibratory motion, since the whole apparatus was insulated from all accession of material heat, by the frozen mass below, and by the vacuum around it. the experiment was afterwards repeated with greater care, and by means of a more refined apparatus: it was modified in different ways; and the results were ultimately published in an essay, to be hereafter noticed, "on heat, light, and the combinations of light," which appeared in a provincial collection of tracts, edited by dr. beddoes, at bristol. mr. davies gilbert, in describing the above experiment in his late address to the royal society, very justly observed that it does not at all decide the important matter in dispute, with respect to an ethereal or transcendental fluid; but that few young men remote from the society of persons conversant with science, will present themselves, who are capable of devising any thing so ingenious. dr. henry, in a paper published in the "memoirs of the manchester society," on entering into a review of this and similar experiments, very truly states, that the mode of insulation is not only imperfect, but that, according to count rumford, caloric will even pass through a torricellian vacuum. the most prominent circumstance in the history of this period of davy's life, is his introduction to mr. davies giddy, now mr. gilbert, the late distinguished and popular president of the royal society. the manner in which this happened is as curious as its result was important; and it furnishes another very striking illustration of the power of simple accident in directing our destinies. mr. gilbert's attention was attracted to the future philosopher, as he was carelessly swinging over the hatch, or half gate, of mr. borlase's house, by the humorous contortions into which he threw his features. davy, it may be remarked, when a boy, possessed a countenance which, even in its natural state, was very far from comely, while his round shoulders, inharmonious voice, and insignificant manner, were calculated to produce any thing rather than a favourable impression: in riper years, he was what might be called "good-looking," although, as a wit of the day observed, his aspect was certainly of the "bucolic" character. the change which his person underwent, after his promotion to the royal institution, was so rapid, that, in the days of herodotus, it would have been attributed to nothing less than the miraculous interposition of the priestesses of helen. a person, who happened to be walking with mr. gilbert upon the occasion alluded to, observed that the extraordinary-looking boy in question was young davy, the carver's son, who, he added, was said to be fond of making chemical experiments. "chemical experiments!" exclaimed mr. gilbert, with much surprise: "if that be the case, i must have some conversation with him." mr. gilbert, as we all know, possesses a strong perception of character, and he therefore soon discovered ample evidence of the boy's singular genius. after several interviews, which confirmed him in the opinion he had formed, he offered young humphry the use of his library, or any other assistance that he might require for the pursuit of his studies; and at the same time gave him an invitation to his house at tredrea, of which he frequently availed himself. during one of his visits, mr. gilbert accompanied him to hayle copper-house, and introduced him to dr. edwards, a gentleman afterwards known to the medical profession as the chemical lecturer in the school of st. bartholomew's hospital; at the time, however, alluded to, he resided at copper-house with his father, and possessed a well-appointed laboratory. the tumultuous delight which davy expressed on seeing, for the first time, a quantity of chemical apparatus, hitherto only known to him through the medium of engravings, is described by mr. gilbert as surpassing all description. the air-pump more especially fixed his attention, and he worked its piston, exhausted the receiver, and opened its valves, with the simplicity and joy of a child engaged in the examination of a new and favourite toy. it is a curious circumstance, that the phenomena resulting from the contact of iron and copper, in the investigation of which davy was destined to perform so prominent a part, were very early noticed by mr. edwards in this place; who found that the flood-gates in the port of hayle decayed with a rapidity wholly inexplicable, but upon the supposition of some _chemical_ action between the metals which had not yet been clearly explained. how little did mr. edwards imagine that the fact, which had so powerfully excited his curiosity, would become to the youth before him, a future source of rich and honourable discovery! during the following year, an event occurred which contributed, in no small degree, to the advancement of davy's prospects. mr. gregory watt, who had long been in a declining state of health, was recommended by his physicians to reside for some time in the west of england, and he accordingly proceeded at once to penzance, and took up his abode, as a lodger and boarder, in the house of mrs. davy. it may be supposed that two kindred spirits would not be long in contracting an acquaintance with each other; in fact, an intimacy of the warmest nature did ultimately grow up between them, and continue to the very moment of mr. watt's premature dissolution: the origin and progress of their friendship, however, are too curious to be passed over without some notice. mr. gregory watt possessed a warm and affectionate heart; but there was a solemn, aristocratic coldness in his manner, which repulsed every approach to familiarity. davy, it has been already stated, did not at that time possess any of those qualifications, in person or manner, which are calculated to produce favourable prepossessions. it may, therefore, be readily imagined how mr. watt must have felt, on finding the son of his landlady familiarly addressing him on subjects of metaphysics and poetry. by one of those strange perversions which have so frequently led great men to conceal the peculiarity of their talents, and to rest their claims to notice and respect upon qualifications which they possessed only in an inferior degree, davy sought to ingratiate himself with mr. watt by metaphysical discussions; but, instead of the admiration, he excited the disgust of his hearer. it was by mere accident that an allusion was first made to chemistry, when davy flippantly observed, that he would undertake to demolish the french theory in half an hour. he had touched the chord: the interest of mr. watt was excited,--he conversed with davy upon his chemical pursuits,--he was at once astonished and delighted at his sagacity,--the barrier of ice was removed, and they became attached friends. mr. wedgwood, and his brother thomas, also spent a winter at penzance; and i have reason to believe that their friendship was of substantial benefit to davy. before i attend the progress of our philosopher to the next scene of life, or proceed to detail the circumstances connected with his departure from penzance, i must relate the following anecdote.--until the formation of the geological society of london occasioned the introduction of more extended and sounder views into the science, geologists were divided into two great rival sects,--into neptunists and plutonists: the one affirming that the globe was exclusively indebted for its present form and arrangement to the agency of water; the other, admitting to a certain extent the operation of water, but maintaining the utter impossibility of explaining the consolidation of the strata without the intervention of fire. every geologist felt bound to side with the one or the other of these contending parties, for neutrality was held as disgraceful as though the law of solon had been in active operation. i shall not easily forget the din and fury of this elemental war, as it raged in edinburgh when i was a student in that university; even the mineral dealers, who, like the artisans of a neutral city, sold arms and ammunition to both sides, still defended their own opinions with party fury. it was amusing to observe the triumph and dismay which, by turns, animated and depressed each side, as the discovery of a new fact, or a fresh specimen, appeared to give a preponderance to the doctrine of fire or water. the fact of so large a portion of the strata being found in the state of a carbonate was advanced by the neptunists as an unanswerable argument against igneous agency: the dismay therefore which this sect received upon the discovery of sir james hall, that under the combined forces of heat and compression, carbonate of lime might be fused, was only equalled by the excessive joy excited in the contending party. we may form some notion of the high importance attached to this discovery, when we learn that its author applied to the government for a flag of truce to convey illustrative specimens to the continental philosophers. it so happened, that the professors of oxford and cambridge ranged themselves under opposite banners: dr. beddoes was a violent and uncompromising plutonist, while professor hailstone was as decided a neptunist. the rocks of cornwall, and their granitic veins, had been appealed to, as affording evidence upon the subject; and the two professors, who, although adverse in opinion, were united in friendship, determined to proceed together to the field of dispute, each hoping that he might thus convince the other of his error, and cure him of his heresy. the belligerents arrived at penzance, and in company with their mutual friend, mr. davies gilbert, examined the coast, and procured specimens with pretty much the same spirit of selection as a schoolboy consults his gradus, not for an epithet of any meaning, but for one which best suits his measure; and having made drawings, disputed obvious appearances, rendered that which was clear to the senses, confused to the understanding, and what was already confused, ten times more obscure, they returned, the opinion of each, as might easily have been anticipated, having been strengthened by the ordeal: the one protesting that the very aspect of the shivered slate was sufficient to prove that the globe must have been roasted to rags; the other, with equal plausibility, declaring that there was not a tittle of evidence to show that the watery solvent had ever even simmered. such, in fact, must ever be the case, when philosophers examine the same subject under such different impressions, and in such opposite points of view; like the two knights who could not agree respecting the colour of the shield, only because each saw a different side of it. rocks, it is said, have flinty hearts, and certain it is that, upon this occasion, cornwall did not afford that assistance against the neptunists, which the oxford professor had sought with so much zeal and confidence; but if deferred revenge had, as we are told is generally the case, been put out at compound interest, and beddoes had exacted its dues with more than judaical rigour, it must be allowed that cornwall, by placing davy at his disposal, would have fully cancelled all demands. plutonian beddoes, erst, in spiteful ire, to see a _hailstone_ mock his central fire, a mighty spirit raised, by whose device we now burn hailstones, and set fire to ice. before quitting this subject, it is but justice to advert to the progress which geology has made since the turbulence of this contest has subsided; it has grown strong in facts, and is daily increasing its stores. it has been wisely said by one of the ancient poets, that in vehement disputes, not only the persons engaged, but every one who is at all interested, must suffer; not only the combatants, but the spectators of the combat,--for it is difficult to apprehend truth while it is the subject of angry contest. to return to the narrative.--upon beddoes establishing the "pneumatic institution" at bristol, he required an assistant who might superintend the necessary experiments in the laboratory; and mr. gilbert proposed davy as a person fully competent to fill the situation. the young candidate had already produced a very favourable impression upon dr. beddoes, by his experiments upon heat and light, which he had some time before transmitted to him through the hands of his friend mr. gregory watt. this fact may be collected from a note appended by dr. beddoes to davy's paper subsequently published in the first volume of the west country contributions, in which the doctor says, "my first knowledge of mr. davy arose from a letter written in april , containing an account of his researches on heat and light." the rest is told in the letters which passed on this occasion between dr. beddoes and mr. gilbert, and from which i shall make such extracts as may be necessary to complete the history of a transaction of much interest and importance. in a letter dated july , , dr. beddoes says, "i am glad that mr. davy has impressed you as he has me. i have long wished to write to you about him, for i think i can open a more fruitful field of investigation than any body else. is it not also his most direct road to fortune? should he not bring out a favourable result, he may still exhibit talents for investigation, and entitle himself to public confidence more effectually than by any other mode. he must be maintained, but the fund will not furnish a salary from which a man can lay up any thing. he must also devote his time for two or three years to the investigation. i wish you would converse with him upon the subject. no doubt he has received my two last letters. i am sorry i cannot at this moment specify a yearly sum, nor can i say with certainty whether all the subscribers will accede to my plan; most of them will, i doubt not. i have written to the principal ones, and will lose no time in sounding them all." in a second letter of the th of july, we find the following observations. "i have received a letter from mr. davy since i wrote to you. he has oftener than once mentioned a _genteel maintenance_, as a preliminary to his being employed to superintend the pneumatic hospital. i fear the funds will not allow an ample salary; he must, however, be maintained. i can attach no idea to the epithet _genteel_, but perhaps all difficulties would vanish in conversation; at least, i think your conversing with mr. davy will be a more likely way of smoothing difficulties, than our correspondence. it appears to me, that this appointment will bear to be considered as a part of mr. davy's medical education, and that it will be a great saving of expense to him. it may also be the foundation of a lucrative reputation; and certainly nothing on my part shall be wanting to secure to him the credit he may deserve. he does not undertake to discover cures for this or that disease; he may acquire just applause by bringing out clear, though negative results. during my journeys into the country, i have picked up a variety of important and curious facts from different practitioners. this has suggested to me the idea of collecting and publishing such facts as this part of the country will, from time to time, afford. if i could procure chemical experiments, that bore any relation to organised nature, i would insert them. if mr. davy does not dislike this method of publishing his experiments, i would gladly place them at the head of my first volume, but i wish not that he should make any sacrifice of judgment or inclination." it remains only to be stated, that mr. gilbert kindly undertook the negotiation, and completed it to the satisfaction of all the principal parties. mrs. davy yielded to her son's wishes, and mr. borlase very generously surrendered his indenture, with an endorsement to the following effect,--that he freely gave up the indenture, on account of the singularly promising talents which mr. davy had displayed. his old and valued friend mr. tonkin, however, not only expressed his disapprobation of this scheme, but was so vexed and irritated at having his favourite plan of fixing davy in his native town as a surgeon, thus thwarted, that he actually altered his will, and revoked the legacy of his house which he had previously bequeathed him. mr. tonkin died on the th of december ; so that, although he lived long enough to witness davy's appointment to the royal institution, he could never have anticipated the elevation to which his genius and talents ultimately raised him. on the nd of october in the year , davy quitted penzance, before he had attained his twentieth year. mr. gilbert well remembers meeting him upon his journey to bristol, and breakfasting with him at okehampton, on the th of october. he was in the highest spirits, and in that frame of mind in which a man of ardent imagination identifies every successful occurrence with his own fortunes; his exhilaration, therefore, was not a little heightened by the arrival of the mail-coach from london, covered with laurels and ribbons, and bringing the news, so cheering to every english heart, of nelson's glorious victory of the nile. chapter ii. cursory thoughts on the advantages of biography.--plan and objects of the pneumatic institution.--davy contracts friendships during his residence at bristol.--his first visit to london.--his letters to mr. davies gilbert.--the publication of the west country contributions, by dr. beddoes.--davy's essays on heat, light, and respiration.--his interesting experiments on bonnet canes.--he commences an enquiry into the nature of nitrous oxyd.--he publishes his chemical researches.--a critical examination of the work.--testimony of tobin, clayfield, southey, and others, respecting the powers of nitrous oxyd.--davy breathes carburetted hydrogen gas, and nearly perishes from its effects.--his new galvanic experiments communicated in a letter to mr. gilbert. having concluded the early history of the subject of these memoirs, and conducted it to that memorable day on which he left his native town, and bursting from obscurity, prepared to enter upon a wider field of usefulness and honour, i shall accompany him in his progress; and with the honest desire of affording instruction as well as amusement,--for history is useful only as it holds up the mirror of truth,--i shall continue to point out the various circumstances that may have contributed to his success and scientific renown; and to offer such occasional reflections as may be likely to illustrate not only the superficial peculiarities which constitute the light and shade of character, but those deeper varieties of mind, upon which the superiority of intellect may be supposed to depend. after all, the great end of biography is not to be found, as some would seem to imagine, in a series of dates, or in a collection of gossiping anecdotes and table-talk, which, instead of lighting up and vivifying the features, hang as a cloud of dust upon the portrait; but it is to be found in an analysis of human genius, and in the developement of those elements of the mind, to whose varied combinations, and nicely adjusted proportions, the mental habits, and intellectual peculiarities of distinguished men may be readily referred. it has been stated that an arrangement had been concluded between dr. beddoes and davy: it is but an act of justice to say, that it was of a liberal and honourable description; and let me also add in this place, that no sooner had davy found himself in a situation which secured for him the necessaries of life, than he renounced all claims upon his paternal property, in favour of his mother and sisters. by acceding to the proposal of dr. beddoes, he never intended to abandon the profession in which he had embarked; on the contrary, he persevered in his determination to study and graduate at edinburgh, and his patron promised that every opportunity should be afforded him at bristol for seeing medical practice: this part of the arrangement, however, was voluntarily abandoned by him, for he soon became so absorbed by the labours of the laboratory, as to leave little leisure for the clinical studies of the hospital. the pneumatic institution was established for the purpose of investigating the medical powers of factitious airs or gases; and to davy was assigned the office of superintending the various experiments. it is now generally acknowledged, that the art of physic has not derived any direct advantage from the application of a class of agents which, undoubtedly, held forth the fairest promise of benefit; but it is too frequently the case, that in physic, theory and experience are in open hostilities with each other. the gases are now never employed in the treatment of disease, except by a few crafty or ignorant empirics, whose business it is to enrich themselves by playing on the credulity of mankind: indeed, we may say of popular remedies in general what m. de lagrange has so wittily said of popular prejudices, that they are the cast-off clothes of philosophers, in which the rabble dress themselves. the investigation, however, into the nature and composition of the gases paved the way to some new and important discoveries in science; so that, to borrow a baconian metaphor, although our philosophers failed in obtaining the treasure for which they so eagerly dug, they at least, by turning up and pulverizing the soil, rendered it fertile. the ingenuity of the chemist will for ever remain on record; the phantoms of the physicians have vanished into air. davy was now constantly engaged in the prosecution of new experiments, in the conception of which, as he himself informs us, he was greatly aided by the conversation and advice of dr. beddoes. he was also occasionally assisted by mr. william clayfield, a gentleman ardently attached to chemical pursuits, and whose name is not unknown in the annals of science; indeed, it appears that to him he was indebted for the invention of a mercurial air-holder, by which he was enabled to collect and measure the various gases submitted to examination. he had also the advantages of some society of a highly intellectual cast: it is sufficient to mention the names of edgeworth and james tobin. in reply to a letter of enquiry which was lately addressed to her, miss edgeworth observes, that "her father possessed much influence over davy's mind;" and that "when he was a very young man at clifton, unknown to fame, mr. edgeworth early distinguished and warmly admired his talents, and gave him much counsel, which sunk deep into his mind." the present lord durham and his brother were also resident in the house of dr. beddoes, not only for their education, but for the benefit of his professional superintendence. besides those who were residing at clifton, the most distinguished in the circles of science and literature paid passing visits to dr. beddoes; with many of whom davy contracted an acquaintance, with some an intimacy, and with a few a solid and permanent friendship. in examining the individuals composing this latter class, we find them differing so widely from each other in character and pursuit, that we are led to enquire upon what principles of affinity his regards could possibly have been attracted--the truth is, that there was more than one avenue to his heart; and the philosopher, the poet, the physician, the philanthropist, and the sportsman, found each, upon different terms, a more or less ready access to its recesses. the chemist who would aspire to his favour, could alone obtain it by laborious application and novel research; the philanthropist, by the practicability of his schemes for improving society, and increasing the sum of its happiness; but the fisherman instantly caught his affections by a hook and line. to be a fly-fisher was, in his opinion, to possess the capabilities of intellectual distinction, although circumstances might not have conspired to call them into action; whilst a proficiency in this art, when exhibited by an individual otherwise distinguished, gave him an additional claim to his attention and regard. the stern courage of nelson, tempered as it was with all the kindly feelings of humanity, was sufficient to excite in the breast of davy the most enthusiastic admiration; but the circumstance of his having been a fly-fisher, and continued the sport, even with his left hand, threw, in his opinion, a still brighter halo around his character. no one who knew him can accuse him of inconstancy in his friendships: amidst the excitements of his station, and the abstractions incident to his pursuits, he might not always have shown those little attentions which are received by the world as the indications of personal regard; but his heart beat not less warmly on that account: when the flame of affection had been once kindled, it burnt with a pure and steady light through life. this will be readily seen in the letters addressed to his several early friends, more especially to mr. poole of nether stowey, in somersetshire, and to mr. clayfield of bristol, from which i shall have occasion to present some interesting extracts. those who had become acquainted with him in early life, and were enabled to watch the whole progress of his career from obscurity to the highest pinnacle of fame, have declared that his extraordinary talents never at any period excited greater astonishment and admiration than during his short residence at bristol. his simplicity of mind and manner was also at this time truly delightful. he scarcely knew the names of our best authors, much less read any of their works; yet upon topics of moral philosophy and metaphysics he would enter into discussion with acknowledged scholars, and not only delight them with the native energy of his mind, but instruct them by the novelty and truth of his conceptions. mr. coleridge lately expressed to me the astonishment he felt, very shortly after his introduction to him, on hearing him maintain an argument upon some abstruse subject with a gentleman equally distinguished for the extent of his erudition, and for the talent of rendering it available for illustration;--the contrast was most striking--it was the fresh and native wild flower, opposed to the elaborate exotic of the _hortus siccus_! during this period he occasionally visited his friend mr. gregory watt, at birmingham; at which place his ambition was constantly excited by intercourse with congenial minds; and his letters to his mother and relations represent him as rejoicing in the success of his experiments, and as delighting in his association with kindred genius; but always casting a longing, lingering thought on the scenes of his boyhood, he spoke with joyful anticipation of the period at which he proposed to revisit his mother and family. that he still continued to regard the practice of physic as the great end and object of all his pursuits, is evident from one of these letters, written in , in which he says, "philosophy, chemistry, and medicine, are my profession." on the st of december he visited london for the first time, and remained about a fortnight; the friends with whom he associated upon this occasion were coleridge, southey, gregory watt, underwood, james and john tobin, thomson, and clayfield; all of whom vied with each other in their exertions to render his visit agreeable, conducting him to such persons and places as were deemed worthy of his notice. of all the letters placed at my disposal, those addressed to his early friend and patron, mr. davies gilbert, are, in my judgment, the most interesting: it is true, that as specimens of epistolary style they have but slender pretensions, and are far less pleasing than those written to mr. poole and others, in later life; but let it be remembered that, as yet, their writer had never enjoyed the advantages of literary correspondence. for the defects, however, of style, there is more than sufficient compensation; they speak from the heart;--they carry with them internal evidence of the honest simplicity of his mind, and they throw a light upon the peculiarities of his genius, which without such aid might be less perfectly understood; above all, they evince an ardour which no difficulties could repress, and a confidence which no failures could extinguish. we clearly discern from his first letters, that he entered upon his career of experiment with an almost chivalrous feeling, flushed with the consciousness of native strength, and exulting in the prospect of destined achievements. i am aware that there are those who still object, with dr. sprat, to the practice of publishing letters which were never intended for the public eye, and i experience the inconvenience, while i respect the delicacy, of such an opinion. i confess, on my own part, i have always considered, with mr. mason, that the objections urged by the learned historian of the royal society are wholly untenable. he talks of "the souls of men thus appearing undressed, or in a habit too negligent to go abroad in the streets, although they might be seen by a few in a chamber." but the undress he would condemn, is the nakedness of truth--the negligent attire, the simple and unadorned expression of those natural and significant traits, whose value incomparably exceeds the premeditated and artificial exhibitions of mind and manner. "_nam in ingenio quoque sicut in agro, quanquam alia diu serantur atque elaborantur, gratiora tamen quæ sua sponte nascuntur._"[ ] [ ] dialogus de oratoribus,--_tacit._ i cannot but suspect that dr. sprat was, upon this occasion, more anxious to display a metaphor, than to illustrate a truth. i have often thought a very curious book might be written to show how greatly, both in physics and in morals, the progress of truth has been retarded, and the judgment of men warped, by the abuse of metaphors; the most correct of which can be nothing more than the image of truth reflected, as it were, from a mirror, and consequently liable to all the delusions of our mental optics. the figure by which nature was represented as "_abhorring a vacuum_," kept us in ignorance of the true theory of the pump for two thousand years after the discovery of the weight, or gravity, of the atmosphere;[ ] and the unfortunate p. l. courier positively owed his conviction to a metaphor in the judge's charge--"_un écrìt plein de poison._"--well might the defendant exclaim, "_sauvez-nous de la metaphore!_" [ ] plutarch, in expressing the opinion of asclepiades upon this subject, represents him as saying, that the external air, _by its weight_, opened its way with force into the breast. seneca also was acquainted with the weight and elastic force of the air; for he describes the constant effort by which it expands itself when it is compressed, and affirms that it has the property of condensing itself, and of forcing its way through all obstacles that oppose its passage.--quæst. nat. lib. v. c. v. and vi. the first of the letters to which i have alluded appears to have been written rather more than five weeks after his arrival at clifton. to davies giddy, esq. clifton, november , . dear sir, i have purposely delayed writing until i could communicate to you some intelligence of importance concerning the pneumatic institution. the speedy execution of the plan will, i think, interest you, both as a subscriber and a friend to science and mankind. the present subscription is, we suppose, nearly adequate to the purpose of investigating the medicinal powers of factitious airs; it still continues to increase, and we may hope for the ability of pursuing the investigation to its full extent. we are negotiating for a house in dowrie square, the proximity of which to bristol, and its general situation and advantages, render it very suitable to the purpose. the funds will, i suppose, enable us to provide for eight or ten patients in the hospital, and for as many out of it as we can procure. we shall try the gases in every possible way. they may be condensed by pressure and rarefied by heat. _quere_,--would not a powerful injecting syringe,[ ] furnished with two valves, one opening into an air-holder and the other into the breathing chamber, answer the purpose of compression better than any other apparatus? can you not, from your extensive stores of philosophy, furnish us with some hints on this subject? may not the non-respirable gases furnish a class of different stimuli? of which the _oxymuriatic acid gas_ would stand the highest, if we might judge from its effects on the lungs; then, probably, _gaseous oxyd of azote_, and _hydro-carbonate_. i suppose you have not heard of the discovery of the native _sulphate of strontian_ in england. i shall perhaps surprise you by stating that we have it in large quantities here. it had long been mistaken for _sulphate of barytes_, till our friend clayfield, on endeavouring to procure the _muriate of barytes_ from it by decomposition, detected the strontian. we opened a fine vein of it about a fortnight ago, at the old passage near the mouth of the severn. it was embodied in limestone and gypsum, the outside of the vein, a striated mass; the internal parts finely crystallized in cubes, of the sp. gr. · . clayfield has been working at it for some time. we have persuaded him to publish his analysis in the first volume of the western physical collection. i have made with him the phosphuret of barytes and of strontian: they possess, in common with that of lime, the property of producing phosphorized hydrogen gas; the phosphuret of strontian, it appears, in a more eminent degree. we have likewise attempted to decompose the boracic and muriatic acids, by passing phosphorus, in vapour, through muriate, and borate of lime, heated red. phosphate of lime was found in the experiment on the boracic acid; but, as no pneumatic apparatus was employed, the experiment was uncertain. we shall repeat them next week. we are printing in bristol the first volume of the 'west country collection,' which will, i suppose, be out in the beginning of january. mrs. beddoes hopes that miss giddy received her letter, and desires me to certify that she wrote almost immediately after the reception of her epistle. she is as good, amiable, and elegant as when you saw her. believe me, dear sir, with affection and respect, truly your's, humphry davy. [ ] here the reader will recognise the force of early associations. the work announced in the above letter was published in the commencement of the year , under the title of "contributions to physical and medical knowledge, principally from the west of england; collected by thomas beddoes, m.d." the first two hundred pages, constituting very nearly half the volume, are the composition of davy, and consist of essays "on heat, light, and the combinations of light." "on phos-oxygen, or oxygen and its combinations;" and "on the theory of respiration." his first essay commences with an experiment, in order to show that light is not, as lavoisier supposed, a modification, or an effect, of heat, but matter of a peculiar kind, _sui generis_, which, when moving through space, or in a state of projection, is capable of becoming the source of a numerous class of our sensations. a small gunlock was armed with an excellent flint, and, on being snapped in an exhausted receiver, did not produce any light. the experiment was repeated in carbonic acid, and with a similar result. small particles were in each case separated from the steel, which, on microscopic examination, evidently appeared to have undergone fusion. whence davy argued, that light cannot be caloric in a state of projection, or it must have been produced in these experiments, where heat existed to an extent sufficient to fuse steel. nor, that it can be, as some have supposed, a vibration of the imaginary fluid ether; for, granting the existence of such a fluid, it must have been present in the receiver. if, then, light be neither caloric in a state of projection, nor the vibration of an imaginary ether, it must, he says, be a substance _sui generis_. with regard to caloric, his opinion that it is not, like light, material, has been already noticed. in the present essay he maintains the proposition by the same method of reasoning as that by which he attempts to establish the materiality of light, and which mathematicians have termed the "_reductio ad absurdum_." in his chapter on "light and its combinations," he indulges in speculations of the wildest nature, although it must be confessed that he has infused an interest into them which might almost be called dramatic. they are certainly highly characteristic of that enlightened fancy, which was perpetually on the wing, and whose flight, when afterwards tempered and directed by judgment, enabled him to abstract the richest treasures from the recesses of abstract truth. taking it for granted that caloric has no existence as a material body, or, in other words, that the phenomena of repulsion do not depend upon the agency of a peculiar fluid, and that, on the contrary, light is a subtle fluid acting on our organs of vision _only when in a state of repulsive projection_, he proceeds to examine the french theory of combustion; the defects of which he considers to arise from the assumption of the imaginary fluid _caloric_, and the total neglect of _light_. he conceives that the light evolved during combustion previously existed in the oxygen gas, which he therefore proposes for the future to call phos-oxygen.[ ] [ ] brugnatelli considered that oxygen, in certain cases of combination, entered into union with different bodies, without parting with its _caloric_; and in that state he gave it the name of therm-oxygen; so that davy had a precedent for his nomenclatural innovation. in following up this question, he would seem to consider light as the _anima mundi_, diffusing through the universe not only organization, but even animation and perception. _phos-oxygen_ he considers as capable of combining with additional proportions of light, and of thus becoming '_luminated phos-oxygen!_'--from the decomposition of which, and the consequent liberation of light, he seeks to explain many of the most recondite phenomena of nature. we cannot but admire the eagerness with which he enlists known facts into his service, and the boldness with which he ranges the wilds of creation in search of analogies for the support and illustration of his views. he imagines that the _phos-oxygen_, when thus _luminated_, must necessarily have its specific gravity considerably diminished by the combination, and that it will therefore occupy the higher regions of the atmosphere; hence, he says, it is that combustion takes place at the tops of mountains at a lower temperature than in the plains, and with a greater liberation of light. the hydrogen which is disengaged from the surface of the earth, he supposes, will rise until it comes into contact with this _luminated phos-oxygen_, when, by its attracting the oxygen to form water, the light will be set free, and give origin to the phenomena of fiery meteors at a great altitude. the phenomenon termed '_phosphorescence_,' or that luminous appearance which certain bodies exhibit after exposure to heat, is attributed by this theory to the light, which may be supposed to quit such substances as soon as its particles have acquired repulsive motion by elevation of temperature. the electric fluid is considered as light in a condensed state, or, in other words, in that peculiar state in which it is not supplied with a repulsive motion sufficiently energetic to impart projection to its particles; for, he observes, that its chemical action upon bodies is similar to that of light; and when supplied with repulsive motion by friction, or by the contact of bodies from which it is capable of subtracting it, it loses the projectile form, and becomes perceptible as light. it is extremely probable, he adds, that the great quantity of this fluid almost everywhere diffused over our earth is produced by the condensation of light, in consequence of the subtraction of its repulsive motion by black and dark bodies; while it may again recover the projectile force by the repulsive motion of the poles, caused by the revolution of the earth on its axis, and thus appear again in the state of sensible light; and hence the phenomenon of the _aurora borealis_, or northern lights. in considering the theory of respiration, he supposes that _phos-oxygen_ combines with the venous blood without decomposition; but that, on reaching the brain, the light is liberated in the form of electricity, which he believes to be identical with the nervous fluid. on this supposition, sensations and ideas are nothing more than motions of the nervous ether; or light exciting the medullary substance of the nerves and brain into sensitive action! he thinks it would be worth while to try, by a very sensible electrometer, whether an insulated muscle, when stimulated into action, would not give indications of the liberation of electric fluid, although he suspects that in man the quantity is probably too small, and too slowly liberated, to be ascertainable. in the torpedo, and in some other animals, however, it is unquestionably given out perceptibly during animal action. when any considerable change takes place in the organic matter of the body, so as to destroy the powers of life, new chemical attractions and repulsive motions take place, and the different principles of which the body is composed enter into new combinations. in this process, which is called putrefaction, davy, in pursuance of this theory, thinks that in land-animals the latent light of the system enters into new combinations with oxygen and nitrogen, but that in fish no such combinations occur, and hence the luminous appearance which accompanies their putrefaction. such is the outline of these extraordinary essays. they stand upon record, and therefore, as a faithful biographer, i was bound to notice them; nor are they devoid of interest or instruction: i am not quite sure that, amidst all the meteors of his fancy, there may not be a gleam of truth. i allude to his theory of respiration: it certainly does not square aôwith the physiological opinions of the day; nor did that of newton, when he conjectured that water might contain an inflammable element; but it was the refraction of a great truth, at that time below the horizon. it was a very ancient opinion, that life, being in its own nature aëriform, is under the necessity of renewing itself by inspiring the air. modern chemistry, by teaching us the nature of the atmosphere, has dispelled many fanciful theories of its action, but it has not yet explained why respiration, the first and last act of life,[ ] cannot be suspended, even for a minute, without the extinction of vitality. when we reflect upon this fact, it is scarcely possible not to believe that the function has been ordained for some greater purpose than that of removing a portion of carbon from the circulating blood. is it unreasonable to conclude that some principle is thus imparted, which is too subtle to be long retained in our vessels, and too important to be dispensed with, even for the shortest period? "i offer this opinion," as montaigne says, "not as being good, but as being my own." [ ] breath and life are synonymous. in the greek, the most philosophically constructed language with which we are acquainted, this _first_ and _last_ act is expressed by a verb composed of alpha and omega--[greek: aô]. in the latin, the connexion between _spiro_ and _spiritus_, breath and life, is evident. by these observations, i am not to be supposed as wishing, for a moment, to uphold the wild hypotheses which i have just related; it must be admitted that the theory of _phos-oxygen_ and _luminated phos-oxygen_ has scarcely a parallel in extravagance and absurdity; and i happen to know that, in after life, davy bitterly regretted that he had so committed himself; any allusion to the subject became a source of painful irritation. it is to be remarked, that in every course of lectures, although davy did not refer to these theories, he frequently alluded to the unphilosophic spirit that had given origin to them; as if he had imposed upon himself this penance as an atonement for his early follies. the following note was taken at one of his lectures:--"after what has been said, it will be useless to enter upon an examination of any of those theories, which, assuming for their foundation the connexion of life with respiration, have attempted to prove that oxygen is the principle of life, and that the wonderful and mysterious phenomena of perception arise from the action of common gravitating substances upon each other. such theories are the dreams of misemployed genius, which the light of experiment and observation has never conducted to truth, and are merely a collection of terms derived from known phenomena, and applied by loose analogies of language to unknown things." the reader, however, will be disposed to treat him with all tenderness when he remembers that the author of these essays was barely eighteen years of age. if blame is to fall on any one, let it fall on dr. beddoes, who never should have sanctioned the publication: had he curbed the ardent and untamed imagination of the young philosopher, he would have acted the part of a wise man and of a kind friend. but the truth is, that much as davy needed the bridle, beddoes[ ] required it still more; for, notwithstanding his talents, he was as little fitted for a mentor as a weathercock for a compass; and had it not been for the ascendency which davy gained over his mind, the ardour of his temperament would have continually urged him beyond the bounds of reason. [ ] the only pun davy is said to have ever made was upon the occasion of mr. sadler being appointed by dr. beddoes as his successor. "i cannot imagine," said he, "why he has engaged _sadler_, unless it is that he may be well _bridled_." caught by the loosest analogies, he would arrive at a conclusion without examining all the conditions of his problem. in the exercise of his profession, therefore, he was frequently led to prescribe plans which he felt it necessary to retract the next hour. his friend mr. t---- had occasion to consult him upon the case of his wife: the doctor prescribed a new remedy; but, in the course of the day he returned in haste, and begged that, before mrs. t---- took the medicine, its effect might be tried on a dog! the following anecdote, which was lately communicated to me by mr. coleridge, will not only illustrate a trait of character, but furnish a salutary lesson to the credulous patron of empirics. as soon as the powers of nitrous oxide were discovered, dr. beddoes at once concluded that it must necessarily be a specific for paralysis. a patient was selected for the trial, and the management of it was entrusted to davy. previous to the administration of the gas, he inserted a small pocket thermometer under the tongue of the patient, as he was accustomed to do upon such occasions, to ascertain the degree of animal temperature, with a view to future comparison. the paralytic man, wholly ignorant of the nature of the process to which he was to submit, but deeply impressed, from the representations of dr. beddoes, with the certainty of its success, no sooner felt the thermometer between his teeth than he concluded that the _talisman_ was in full operation, and in a burst of enthusiasm declared that he already experienced the effects of its benign influence throughout his whole body:--the opportunity was too tempting to be lost--davy cast an intelligent glance at mr. coleridge, and desired the patient to renew his visit on the following day, when the same ceremony was again performed, and repeated every succeeding day for a fortnight, the patient gradually improving during that period, when he was dismissed as cured, no other application having been used than that of the thermometer. dr. beddoes, from whom the circumstances of the case had been intentionally concealed, saw in the restoration of the patient the confirmation of his opinion, and the fulfilment of his most ardent hope--nitrous oxide was a specific remedy for paralysis! "it were criminal to retard the general promulgation of so important a discovery; it were cruel to delay the communication of the fact until the publication of another volume of his '_contributions_;' the periodical magazines were too slow in their rate of travelling,--a flying pamphlet would be more expeditious; paragraphs in the newspapers; circulars to the hospitals:"--such were the reflections and plans which successively agitated the physician's mind, when his eyes were opened to the unwelcome truth by davy's confessing the delusion that had been practised. a short time after the publication of the first volume of the "contributions," davy addressed to his friend the following letter:-- to davies giddy, esq. clifton, feb. , . dear friend,--for i love you too well to call you by a more ceremonious name,--i have delayed writing to you from day to day, expecting that some of our experiments would produce results worthy of communication. since i received your last very acceptable letter, i have been chiefly employed in pursuing the experiments on heat, light, respiration, &c. of these experiments i shall give you no account, as you will see them in print. i sent you a copy of my essays last week; if you have not received them, i trust you will find them at my mother's, or at mr. tonkin's. in the same parcel were two small packets, one from mrs. beddoes for your father, the other for miss giddy from mrs. willoughby. about a fortnight ago i sent a few chemical instruments to mr. penneck of penzance; and inclosed with them were specimens of the different varieties of sulphate of strontian addressed to you. if you have not received them, you will get them by sending to mr. penneck. on looking over a box of minerals last week, which was sent to dr. beddoes from cumberland, i found two very fine specimens of sulphate of strontian, marked by the collector _laminated shorl_. i suspect this mineral is not scarce in calcareous countries; it is, i dare say, often mistaken for sulphate of barytes. i have succeeded in combining strontian with the oxygenated muriatic acid. this salt possesses most astonishing properties;[ ] you will find an account of them in my essay. when you have perused my papers, i shall be very much obliged to you for a criticism upon them. when i left penzance, i was quite an infant in speculation,--i knew very little of light or heat. i am now as much convinced of the non-existence of caloric, as i am of the existence of light. independent of the experiments which appear to demonstrate its non-existence directly, and of which you will find an account in my essay, the consideration of certain phenomena leads me to suppose that there would be no difficulty in proving its non-existence by reasoning. these considerations have occurred to me since the publication of the work. i could now render it much more perfect; but i hope soon to complete the investigation of the combinations of light, and to produce a much more perfect work on the subject. i shall be infinitely obliged to you for any hints or observations, as far as the detection of errors of any kind, for it is no flattery to say that i pay greater deference to your opinion than to that of any other philosopher. we intend next week to endeavour to ascertain, by the aid of a delicate balance, the quantities of light liberated in different combustive processes. that there is a deficiency of weight, i am convinced from many experiments. the experiments on light, &c. have prevented me from attempting the decomposition of the undecompounded acids. we have ordered an apparatus at the glass-house for this purpose, and i hope next week we shall be able to carry on the investigation. two modes of effecting these decompositions have occurred to me:--first, to bring phosphorus or sulphur, in the gaseous state, in contact with the acid gases in a tube heated intensely; secondly, to send sulphur in the gaseous state through muriate of copper or lead, heated white. the attraction of sulphur for oxygen, of copper for oxygen, and of sulphur for copper, will probably effect the decomposition. our laboratory in the pneumatic institution is nearly finished, and we shall begin the investigations in about a fortnight. we shall begin by trying the gases in their simplest mode of application, and gradually carry on the more complex processes. i hope the gaseous oxide of azote will prove to be a specific stimulus for the absorbents. i was last week surprised by a letter from mr. watt, announcing the success of their trial. when i was at birmingham five weeks ago, the family were in very low spirits. i spent nine or ten days there, chiefly with mr. keir and mr. watt: i had a great deal of chemical conversation with them. mr. keir is one of the best-informed men i have ever met with, and extremely agreeable. both he and mr. watt are still phlogitians; but mr. keir altogether disbelieves the doctrine of _calorique_. what news have you in cornwall? has mr. john hawkins returned to his native county? he will doubtless be a great acquisition to you. pray do you know whether the zoophyta and marine worms are susceptible of the galvanic stimulus? experiments on them would go far to determine whether the irritable or sensitive fibre is primarily affected. i know of little general scientific news. in the last volume of the _annales de chimie_ is a curious paper by berthollet on sulphurated hydrogen: he makes it out to be an acid. i shall most anxiously expect a letter from you, and i remain with affection and respect, yours, humphry davy. [ ] the following is the account given in his essay. "when sulphuric acid was poured into a solution of this salt in water, a beautiful and unexpected phenomenon took place. the room was accidentally darkened at the moment this experiment was made, so that we were enabled to perceive a vivid luminous appearance. this experiment, independent of its beauty, is extremely pleasing as affording an instance of true combustion, that is, the production of light and heat by the mixture of two incombustible bodies." it may be presumed, that this phenomenon arose from the developement and decomposition of a portion of euchlorine, a compound which he subsequently discovered in . in the year , chevreul announced, as a new discovery, that if strontian be heated in contact with muriatic acid gas, the gas is absorbed, and the earthy salt becomes red hot.--_see annals of philosophy_, vol. ii. p. . the letter which follows may be considered as a reply to one received from mr. davies gilbert, which, it would appear, contained strictures upon his recently published essays. to davies giddy, esq. april , . my dear friend, the engagements resulting from the establishment of the pneumatic institution, and from a course of experiments, to which i have been obliged to pay great attention, have prevented me from acknowledging to you my obligations for the very great pleasure i received from your last excellent letter. in experiments on light and heat, we have to deal with agents whose changes we are unable directly to estimate. the most we can hope for is such an arrangement of facts as will account for most of the phenomena. the supposition of active powers common to all matter, from the different modifications of which all the phenomena of its changes result, appears to me more reasonable than the assumption of certain imaginary fluids alone endowed with active powers, and bearing the same relation to common matter, as the vulgar philosophy supposes spirit to bear to matter. that the particles of bodies must move, or separate from each other, when they become expanded, is certain. a repulsive motion of the particles is directly the cause of expansion; and when bodies are expanded by friction, under circumstances in which there could be no heat communicated by bodies in contact, no oxidation and no diminution of capacity, i see no difficulty in conceiving the repulsive motion generated by the mechanical motion. your excellent and truly philosophic observations will induce me to pay greater attention to all my positions. it is only by forming theories, and then comparing them with facts, that we can hope to discover the true system of nature. i will endeavour very soon to give an answer to the remaining part of your excellent letter. i have now just room to give you an account of the experiments i have lately been engaged in, though they are not much connected with light and heat. _first._--one of mr. william coate's children accidentally discovered that two bonnet-canes rubbed together produced a faint light. the novelty of this phenomenon induced me to examine it, and i found that the canes on collision produced sparks of light, as brilliant as those from the flint and steel. _secondly._--on examining the epidermis, i found, when it was taken off, that the canes no longer gave light on collision. _thirdly._--the epidermis, subjected to chemical analysis, had all the properties of silex. _fourthly._--the similar appearance of the epidermis of reeds, corn, and grasses, induced me to suppose that they likewise contained silex. by burning them carefully, and analysing their ashes, i found that they contained it in rather larger proportions than the canes. _fifthly._--the corn and grasses contain sufficient potash to form glass with their flint. a very pretty experiment may be made on these plants with the blow-pipe. if you take a straw of wheat, barley, or hay,[ ] and burn it, beginning at the top, and heating the ashes with the blue flame, you will obtain a perfect globule of hard glass fit for microscopic experiments. i made a discovery yesterday which proves how necessary it is to repeat experiments. the gaseous oxide of azote is perfectly respirable when pure. it is never deleterious but when it contains nitrous gas. i have found a mode of obtaining it pure, and i breathed to-day, in the presence of dr. beddoes and some others, sixteen quarts of it for near seven minutes. it appears to support life longer than even oxygen gas, and absolutely intoxicated me. pure oxygen gas produced no alteration in my pulse, nor any other material effect; whereas this gas raised my pulse upwards of twenty strokes, made me dance about the laboratory as a madman, and has kept my spirits in a glow ever since. is not this a proof of the truth of my theory of respiration? for this gas contains more light in proportion to its oxygen than any other, and i hope will prove a most valuable medicine. we have upwards of eighty out-patients in the pneumatic institution, and are going on wonderfully well. i shall hope for the favour of a letter from you, and in my answer to it will fully inform you of our proceedings. i have just room to add that i am yours, with affection and respect, humphry davy. [ ] it is very common, after the burning of a hay-stack, to find glass in the ashes. p. i cannot suffer the experiments with the bonnet-canes to pass, without endeavouring to infuse into the reader a portion of that admiration which i feel in relating them. they furnish a beautiful illustration of that combination of observation, experiment, and analogy, first recommended by lord bacon, and so strictly adopted by davy in all his future grand researches. in alluding to this discovery--that siliceous earth exists generally in the epidermis of hollow plants--davy observes in his agricultural lectures, that "the siliceous epidermis serves as a support, protects the bark from the action of insects, and seems to perform a part in the economy of these feeble vegetable tribes, similar to that performed in the animal kingdom by the shell of the crustaceous insects." the circumstance that first led him to the investigation of the nature of _nitrous oxide_, or the _gaseous oxide of azote_, alluded to in the foregoing letter, has been thus recorded by himself. "a short time after i began the study of chemistry, in march , my attention was directed to the _dephlogisticated nitrous gas_ of priestley (nitrous oxide) by dr. mitchell's theory of contagion, by which he attempted to prove that _dephlogisticated nitrous gas_! which he calls _oxide of septon_, was the principle of contagion, and capable of producing the most terrible effects, when respired by animals in the minutest quantities, or even when applied to the skin, or muscular fibre. "the fallacy of this theory was soon demonstrated by a few coarse experiments, made on small quantities of this gas procured, in the first instance, from zinc and diluted nitrous acid. wounds were exposed to its action; the bodies of animals were immersed in it without injury; and i breathed it, mingled in small quantities with common air, without any remarkable effects. an inability to procure it in sufficient quantities prevented me, at this time, from pursuing the experiments to any greater extent. i communicated an account of them to dr. beddoes." his situation in the "medical pneumatic institution" in , imposing upon him the duty of investigating the physiological effects of such aëriform fluids as held out any promise of useful agency, he resumed the investigation; a considerable period, however, elapsed, before he succeeded in procuring _nitrous oxide_ in a state of purity; he was therefore obliged to breathe it in mixture with oxygen gas, or common air; but as no just conclusion could be deduced from the action of an impure gas, he commenced an enquiry for the purpose of discovering a process by which it might be procured in an uncontaminated condition; when, after a most laborious investigation concerning its composition, properties, and combinations, enquiries which were necessarily extended to the different bodies connected with nitrous oxide, such as _nitrous gas_, _nitrous acid_, and _ammonia_, he was enabled, by a series of intermediate and comparative experiments, to reconcile apparent anomalies, and thus, by removing the greater number of those difficulties which had previously obscured this branch of science, to present to the chemical world the first satisfactory history of the combinations of oxygen and nitrogen. thus prepared, he proceeded to examine the action of nitrous oxide upon living beings, and to compare it with the effects of other gases upon man; and in this manner he completed its physiological, as he had already done its chemical history. these interesting results were published in a distinct volume, in the year , entitled, "researches chemical and philosophical, chiefly concerning nitrous oxide, and its respiration. by humphry davy, superintendent of the medical institution." it may be observed in passing, that the merits of this work could never have been inferred from the title-page, which its most sanguine admirers must admit to be as clumsy and unpromising an invitation as an author ever addressed to his scientific brethren. amongst davy's letters to mr. gilbert, i find one written on a proof sheet of the chapter of contents of the above work, and which may not be uninteresting in this place. to davies giddy, esq. july , . that our feelings, as well as our actions, are rendered stronger and more vivid by habit, is probable from many facts, and from no one more so than that of procrastination. my much respected friend, two months after my return,[ ] i had formed the resolution of writing to you; week after week this resolution was renewed and put off to a future day, with the hope that this day, by presenting something new, would enable me to make my letter more interesting. in vain! the feeling of procrastination, thus increased by association, at length became so strong as to prevent me from writing at all.[ ] i have received your letter; it has awakened my duties, and has been doubly welcome, as being unexpected and undeserved. since my return to the pneumatic institution in december, i have been almost incessantly occupied, from january to april, in completing a series of experiments on gases, and their application; and from april to the present time, in writing and printing an account of them. i have written this letter on the table of contents of a work which will be published in the course of the month, and of which i shall take the earliest opportunity to send you a copy. this table of contents will give you a better idea of the nature and extent of the investigation, than i could possibly have given in a letter. we have been repeating the galvanic experiments with success. nicholson, by means of a hundred pieces of silver and zinc, has procured a visible spark. cruickshank has revived oxidated metals in solution, by means of the nascent hydrogen produced from the decomposition of water by the shock; and both he and carlisle have absolutely resolved water into oxygen and hydrogen by means of it, making use of silver and platina wires. an immense field of investigation seems opened by this discovery: may it be pursued so as to acquaint us with some of the laws of life! you have, undoubtedly, heard of herschel's discovery concerning the production of heat by invisible rays emitted from the sun. by placing one thermometer within the red rays, separated by a prism, and another beyond them, he found the temperature of the outside thermometer raised more than that of the inside one. when i first heard of mr. tennant's discovery,[ ] i was very much struck by an observation which you long ago made to me, on the fertility of the cornish lands, in which there was decomposed, _feltspar_ or _serpentine_. mr. tennant spent a day here some time ago, when i mentioned your observation to him, but he could not give any solution of the phenomenon. _quere._--as lime and magnesia are probably both subservient to vegetation, only from supplying plants with carbonic acid, may not lime, when mingled with magnesia, in the process of vegetation, render it partially caustic, and thus enable it to destroy them? your observation on the scale of numbers, and the fact relative to it, are highly interesting. reasoning on this subject would literally form the logic of generalization, or the application of one term to signify many terms, or many ideas, on which science ultimately depends. _quere._--how far have the first attempts at generalization arisen from accident, and how far from the resemblance between ideas? dr. beddoes has always ridiculed the "_tractors_," in common with all other reasonable men. he is about to publish a new work on the nitrous acid. j. wedgwood is returned, very little altered for the better. coleridge is gone to reside in cumberland; he was here the week before last, and spent much time with me, and often spoke of you with the greatest interest. clayfield is at this moment chiefly engaged in commercial speculations. he has found a new mode of making soda, which there is every reason to believe will turn out profitable. i hope some time in the autumn to see you, and to enjoy the well remembered pleasure of your conversation; in the mean while, i remain, with respects to your family, yours with sincere affection, humphry davy. [ ] from his visit to london, as noticed at page . [ ] with respect to the metaphysical speculation contained in this paragraph of his letter, had he not written it in haste, we might presume he would have given a more exact expression to his ideas. by the misapplied term "_feeling of procrastination_," he doubtless meant to describe that aversion to labour which becomes habit by indulgence, and the perception of which, so far from increasing in vividness, actually languishes to obtuseness. to borrow an expression from dr. johnson, davy, in his metaphysical speculations, not unfrequently trod upon the brink of meaning, where light and darkness begin to mingle. [ ] davy here alludes to the fact of magnesian earth being prejudicial to vegetation. in estimating the early genius of davy, and his character as a philosopher, the style and matter of his "researches" will afford us much assistance. the close philosophical reasoning,--the patient and penetrating industry,--the candid submission to every intimation of experiment, and the accuracy of manipulation, so remarkably displayed throughout this work, have been rarely equalled, and perhaps never surpassed. there is scarcely to be found a more striking illustration of chemical genius, than that afforded by his chapter on the "absorption of _nitrous gas by solutions of green sulphate of iron_." the address with which he gradually disentangles the subject of its difficulties, and catches at every opening to truth, affords a study which may be safely recommended to the attention of every young experimentalist, as being no less instructive than it is beautiful. the phenomena attending the absorption of _nitrous gas_ by solutions of _sulphate of iron_ had been examined by vauquelin and by berthollet, but the conclusions of these chemical philosophers were fatally infected by errors, arising from the neglected action of the atmosphere. davy, by conducting his experiments over mercury, proved that, in the absence of air, the absorption was simply owing to a combination between the gas and the fluid; but that, on admitting air, the nitrous _gas_ became nitrous _acid_, a portion of which, together with a part of the water, subsequently underwent decomposition, and gave origin to _ammonia_, and ultimately to _nitrate of ammonia_, while the iron passed into the state of a _peroxide_. we have also to admire in this work an ardour for investigation, which even the most imminent personal danger could not repress. he may truly be said to have sought the bubble reputation in the very jaws of death. what shall we say of that spirit which led him to inspire nitrous gas, at the hazard of filling his lungs with the vapour of _aqua fortis_! or what, of that intrepid coolness which enabled him to breathe a deadly gas, and to watch the advances of its chilling power in the ebbing pulsations at the wrist! these experiments, however, are far too interesting and important to be related in any other than the author's own words; but it is first necessary that his trials with the _nitrous oxide_ should be considered. he found that this gas might be most conveniently, as well as most economically, prepared by the decomposition of a salt known by the name of _nitrate of ammonia_, by the application of a regulated heat; but, as the researches by which he arrived at this conclusion are recorded at length in his work, and as the most important of them are now embodied in every elementary system of chemistry, it would not only be tedious but useless, to enter into a detail of them upon this occasion. "in april," he says, "i obtained nitrous oxide in a state of purity, and ascertained many of its chemical properties. reflections upon these properties, and upon former trials, made me resolve to inspire it in its pure form, for i saw no other way in which its respirability, or powers, could be determined. "i was aware of the danger of the experiment. it certainly would never have been made, if the hypothesis of dr. mitchell had in the least influenced my mind. i thought that the effects might, possibly, be depressing and painful; but there were many reasons which induced me to believe, that a single inspiration of a gas, apparently possessing no immediate action on the irritable fibre, could neither destroy, nor materially injure, the powers of life. "on april th, i made the first inspiration of pure nitrous oxide. it passed through the bronchiæ without stimulating the glottis, and produced no uneasy sensations in the lungs. "the result of this experiment proved that the gas was respirable, and induced me to believe that a farther trial of its effects might be made without danger. "on april th, dr. kinglake being accidentally present, i breathed three quarts of nitrous oxide from and into a silk bag, for more than half a minute, without previously closing my nose, or exhausting my lungs. the first inspirations occasioned a slight degree of giddiness, which was succeeded by an uncommon sense of fulness in the head, accompanied with loss of distinct sensation and voluntary power,--a feeling analogous to that produced in the first stage of intoxication; but unattended by pleasurable sensation. dr. kinglake, who felt my pulse, informed me that it was rendered quicker and fuller. "this trial did not satisfy me with regard to its powers: comparing it with the former ones, i was unable to determine whether the operation was stimulant or depressing. "i communicated the result to dr. beddoes, and on april the th, he was present when the following experiment was made. "having previously closed my nostrils, and exhausted my lungs, i breathed four quarts of the gas from and into a silk bag. the first feelings were similar to those produced in the last experiment; but in less than half a minute, the respiration being continued, they diminished gradually, and were succeeded by a sensation analogous to gentle pressure on all the muscles, attended by an highly pleasurable thrilling, particularly in the chest and in the extremities. the objects around me became dazzling, and my hearing more acute. towards the last inspirations, the thrilling increased, the sense of muscular power became greater, and, at last, an irresistible propensity to action was indulged in: i recollect but indistinctly what followed; i know that my motions were various and violent. "these effects very soon ceased after the respiration of the gas. in ten minutes i had recovered my natural state of mind. the thrilling in the extremities continued longer than the other sensations. "this experiment was made in the morning; no languor or exhaustion was consequent; my feelings throughout the day were as usual, and i passed the night in undisturbed repose. "the next morning the recollection of the effects of the gas was very indistinct; and had not remarks written immediately after the experiment recalled them to my mind, i should even have questioned their reality." our philosopher very naturally doubted whether some of these strong emotions might not, after all, be attributed to the enthusiasm necessarily connected with the perception of agreeable feelings, when he was prepared to expect painful sensations; but he says, that subsequent experiments convinced him that the effects were solely owing to the specific operation of the gas. he found that he could breathe nine quarts of nitrous oxide for three minutes, and twelve quarts for rather more than four; but that he could never breathe it, in any quantity, so long as five minutes. whenever its operation was carried to the highest extent, the pleasurable thrilling, at its height about the middle of the experiment, gradually diminished, the sense of pressure on the muscles was lost, impressions ceased to be perceived, vivid ideas passed rapidly through the mind, and voluntary power was altogether destroyed, so that the mouthpiece generally dropped from his unclosed lips. when he breathed from six to seven quarts, muscular motions were produced to a great extent: sometimes he manifested his pleasure by stamping, or laughing only; at other times, by dancing round the room, and vociferating. during the progress of these experiments, it occurred to him that, supposing _nitrous oxide_ to be analogous in its operation to common stimulants, the debility occasioned by intoxication from fermented liquors ought to be increased after excitement from this gas, in the same manner as the debility produced by two bottles of wine is increased by a third. to ascertain whether this was the case, he drank a bottle of wine, in large draughts, in less than eight minutes. his usual drink, he tells us, was water; he had been little accustomed to take spirits or wine, and had never been intoxicated but once before in the course of his life. under such circumstances, we may readily account for the powerful effects produced by this quantity of wine, and which he describes in the following manner:-- "whilst i was drinking, i perceived a sense of fulness in the head, and throbbing of the arteries, not unlike that produced in the first stage of nitrous oxide excitement: after i had finished the bottle, this fulness increased, the objects around me became dazzling, the power of distinct articulation was lost, and i was unable to stand steadily. at this moment, the sensations were rather pleasurable than otherwise; the sense of fulness in the head, however, soon increased, so as to become painful, and in less than an hour i sunk into a state of insensibility. in this situation i must have remained for two hours, or two hours and a half. i was awakened by head-ache and painful nausea. my bodily and mental debility were excessive, and the pulse feeble and quick. "in this state, i breathed for near a minute and a half five quarts of gas, which was brought to me by the operator for nitrous oxide; but as it produced no sensations whatever, and apparently rather increased my debility, i am almost convinced that it was, from some accident, either common air, or very impure nitrous oxide. "immediately after this trial, i respired twelve quarts of oxygen for nearly four minutes. it produced no alteration in my sensations at the time, but immediately afterwards i imagined that i was a little exhilarated. "the head-ache and debility still, however, continuing with violence, i examined some nitrous oxide which had been prepared in the morning, and finding it very pure, i respired seven quarts of it for two minutes and a half. i was unconscious of head-ache after the third inspiration; the usual pleasurable thrilling was produced, voluntary power was destroyed, and vivid ideas rapidly passed through my mind; i made strides across the room, and continued for some minutes much exhilarated; but languor and depression, not very different in degree from those existing before the experiment, succeeded; they however gradually went off before bed-time. "this experiment proved, that debility from intoxication was not increased by excitement from nitrous oxide. the head-ache and depression would probably have continued longer, had it not been administered." the same work contains an account of many other trials; but sufficient has been extracted to show the zeal and intrepidity with which he conducted his researches. to withhold, however, the testimony which several other scientific persons have given, with respect to the intoxicating influence of this gas, would be to deprive the reader of some very amusing descriptions. first appears mr. w. tobin, who tells us that he soon found his nervous system agitated by the highest sensations of pleasure, but which were difficult of description. when the bags were exhausted and taken from him, he suddenly started from his chair, and vociferating with pleasure, made towards those that were present, as he wished they should participate in his feelings. he struck gently at davy, and a stranger entering the room at the same moment, he made towards him, and gave him several blows, but he adds, it was more in the spirit of good-humour, than in that of anger. he then ran through different rooms in the house, and at last returned to the laboratory, somewhat more composed, although his spirits continued much elevated for some hours after the experiment; he felt, however, no consequent depression, either in the evening or day following. upon another occasion, he states that his sensations were superior to any thing he ever before experienced; his step was firm, and all his muscular power increased. his nerves were more alive to every surrounding impression; he threw himself into several theatrical attitudes, and traversed the laboratory with a quick step, while his mind was elevated to a most sublime height: he says that "it is giving but a faint idea of his feelings to say, that they resembled those produced by a representation of an heroic scene on the stage, or by reading a sublime passage in poetry, when circumstances contribute to awaken the finest sympathies of the soul." the influence, however, of this inspiring agent appears to have been as transitory as its effects were vivid; for he afterwards observes, "i have seldom lately experienced vivid sensations. the pleasure produced by the gas is slight and tranquil, and i rarely feel sublime emotions, or increased muscular power." the first time that mr. clayfield breathed the gas, it produced feelings analogous to those of intoxication. he was for some time unconscious of existence, but at no period of the experiment were his sensations agreeable; a momentary nausea followed, but unconnected with languor or head-ache. in a subsequent trial, it would appear that he did experience certain thrillings which were highly pleasurable. the account given by dr. kinglake agrees pretty much with those already cited. he adds, however, that the inspiration of the gas had the further effect of reviving rheumatic irritations in the shoulder and knee-joints, which had not been previously felt for many months. next appears mr. southey, the laureate. the reader will no doubt be prepared to hear that the nitrous oxide transported him, at least, to the summit of parnassus;--by no means: he laughed when the bag was removed from his mouth, but it may be fairly questioned whether this might not have been an expression of joy at the terrors he had escaped; for he freely confesses that he could not distinguish between the first feelings it occasioned, and an apprehension of which he was unable to divest himself. the first time mr. coleridge inspired the nitrous oxide, he felt a highly pleasurable sensation of warmth over his whole frame: he adds, that the only motion which he felt inclined to make, was that of laughing at those who were looking at him: a symptom as equivocal, perhaps, as that exhibited by the laureate. a number of other accounts are given, but those already related are perhaps sufficient to establish the fact, that the gas in question possesses an intoxicating quality, to which the enthusiasm of persons submitting to its operation has imparted a character of extravagance wholly inconsistent with truth. it will be admitted that there must have been something singularly ludicrous in the whole exhibition. imagine a party of grave philosophers, with bags of silk tied to their mouths, stamping, roaring, and laughing about the apartment; it is scarcely possible to conceive a richer subject for the pencil of a bunbury. we cannot then be surprised at any terms of ridicule in which a stranger, witnessing such an operation, might describe it. m. t. fievée[ ] appears to have considered the practice as a national vice, and whimsically introduces it amongst the catalogue of follies to which he considers the english nation to be addicted. [ ] lettres sur l'angleterre, . taking leave of these laughing philosophers, we must now proceed to a much more serious branch of the subject of pneumatic medicine. "having observed," says davy, "that no painful effects were produced by the application of nitrous gas to the bare muscular fibre, i began to imagine that this gas might also be breathed with impunity, provided it were possible in any way to free the lungs of common air before inspiration, so as to prevent the formation of nitrous acid. "on this supposition, during a fit of enthusiasm produced by the respiration of nitrous oxide, i resolved to endeavour to breathe nitrous gas: one hundred and fourteen cubic inches of it were accordingly introduced into the large mercurial air-holder; two small silk bags of the capacity of seven quarts were filled with nitrous oxide. "after a forced exhaustion of my lungs, my nose being accurately closed, i made three inspirations and expirations of nitrous oxide in one of the bags, in order to free my lungs, as much as possible, from atmospheric oxygen; then, after a full expiration of the nitrous oxide, i transferred my lips from the mouthpiece of the bag to that of the air-holder, and, turning the stop-cock, attempted to inspire the nitrous gas. in passing through my mouth and fauces, it tasted astringent and highly disagreeable; it occasioned a sense of burning in the throat, and produced a spasm of the epiglottis, so painful as to oblige me to desist immediately from attempts to inspire it. after removing my lips from the mouthpiece, when i opened them to inspire common air, _nitrous acid_ was immediately formed in my mouth, which burnt the tongue and palate, injured the teeth, and produced an inflammation of the mucous membrane, which lasted for some hours. "as, after the respiration of nitrous oxide, a small portion of the residual atmospheric air always remained in the lungs mingled with the gas, so is it probable that, in the experiment just related, a minute portion of nitrous acid was formed; and, if so, i perhaps owe the preservation of my life to the circumstance; for, supposing that i had succeeded in taking a full inspiration of nitrous gas, and even that it had not produced any positive effects, it is not likely that i should, by breathing nitrous oxide, have so completely freed my lungs from it, as to have prevented the formation of nitrous acid, when i again inspired common air. i never design again to attempt so rash an experiment." his attempt to breathe carburetted hydrogen gas was scarcely less terrific and appalling. "mr. watt's observations on the respiration of diluted _hydro-carbonate_ by man, and the experiments of dr. beddoes on the destruction of animals by the same gas, proved that its effects were highly deleterious. "as it destroyed life, apparently by rendering the muscular fibre inirritable, without producing any previous excitement, i was anxious to compare its sensible effects with those of nitrous oxide, which at this time i believed to destroy life by producing the highest possible excitement. "in the first experiment, i breathed for nearly a minute three quarts of _hydro-carbonate_, mingled with nearly two quarts of atmospheric air.[ ] it produced a slight giddiness, pain in the head, and a momentary loss of voluntary power; my pulse was rendered much quicker and more feeble. these effects, however, went off in five minutes, and i had no return of giddiness. [ ] "i believe it had never been breathed before by any individual in a state so little diluted." "emboldened by this trial, i introduced into a silk bag four quarts of gas nearly pure, which was carefully produced from the decomposition of water by charcoal an hour before, and which had a very strong and disagreeable smell. "my friend mr. james tobin, junior, being present, after a forced exhaustion of my lungs, the nose being accurately closed, i made three inspirations and expirations of the hydro-carbonate. the first inspiration produced a sort of numbness and loss of feeling in the chest, and about the pectoral muscles. after the second, i lost all power of perceiving external things, and had no distinct sensation, except that of a terrible oppression on the chest. during the third expiration, this feeling subsided, i seemed sinking into annihilation, and had just power enough to cast off the mouthpiece from my unclosed lips. "a short interval must have passed, during which i respired common air, before the objects around me were distinguishable. on recollecting myself, i faintly articulated, '_i do not think i shall die._' placing my finger on the wrist, i found my pulse thread-like, and beating with excessive quickness. in less than a minute, i was able to walk, and the painful oppression on the chest directed me to the open air. "after making a few steps, which carried me to the garden, my head became giddy, my knees trembled, and i had just sufficient voluntary power to throw myself on the grass. here the painful feelings of the chest increased with such violence as to threaten suffocation. at this moment i asked for some nitrous oxide. mr. dwyer brought me a mixture of that gas with oxygen, and i breathed it for a minute, and believed myself recovered. "in five minutes the painful feelings began gradually to diminish; in an hour they had nearly disappeared, and i felt only excessive weakness, and a slight swimming of the head. my voice was very feeble and indistinct. "i afterwards walked slowly for half an hour with mr. tobin, and on my return was so much stronger and better as to believe that the effects of the gas had entirely passed off; though my pulse was , and very feeble. i continued without pain for nearly three quarters of an hour, when the giddiness returned with such violence as to oblige me to lie on the bed; it was accompanied with nausea, loss of memory, and deficient sensation. "in about an hour and a half, the giddiness went off, and was succeeded by an excruciating pain in the forehead, and between the eyes, with transient pains in the chest and extremities. "towards night these affections gradually diminished; and at ten no disagreeable feeling, except weakness, remained. i slept sound, and awoke in the morning very feeble and very hungry. no recurrence of the symptoms took place, and i had nearly recovered my strength by the evening. "i have been minute in the account of this experiment, because it proves, that _hydro-carbonate_ acts as a sedative; that is, it produces diminution of vital action, and consequent debility, without previously exciting. there is every reason to believe that, had i taken four or five inspirations, instead of three, they would have destroyed life immediately, without producing any painful sensation." the scientific and medical world are alike indebted to davy for this daring experiment; and, if the precautions it suggests be properly attended to, it may become the means of preserving human life. the experiment is also valuable as affording support to physiological views, with which its author was probably not acquainted. in the first place, it may be necessary to apprize some of my readers, that the "_hydro-carbonate_" here spoken of, differs very little from the gas now so generally used to illuminate our streets and houses. we have just seen how deadly are its qualities, and that even in a state of extreme dilution it will affect our sensations. the question then necessarily suggests itself, how far this gas can be safely introduced into the interior of our apartments? did we not possess any direct evidence upon the subject, the answer would be sufficiently obvious, since it is impossible so to conduct its combustion, that a portion shall not escape unburnt. such is the theory; but what is our experience upon the subject?--that pains in the head, nausea, and distressing languor, have been repeatedly experienced in our theatres and saloons, by persons inhaling the unburnt gas; that the atmosphere of a room, although spacious and empty, will, if lighted with gas, convey a sense of oppression to our organs of respiration, as if we were inhaling an air contaminated with the breath of a hundred persons. in the next place, davy's experiment is important, inasmuch as it proves that, in cases of asphyxia, or suspended animation, there exists a period of danger after the respiration has been restored, and the circulation re-established, at which death may take place, when we are the least prepared to expect it. bichat has shown that, when dark-coloured blood is injected into the vessels of the brain by means of a syringe connected with the carotid artery, the functions of the brain become immediately disturbed, and in a short time entirely cease: the effect is precisely similar, whether the dark-coloured blood be transmitted to the brain by the syringe of the experimentalist, or by the heart itself. thus in cases of asphyxia, the dark-coloured blood which has been propelled through the vessels during the suspension or imperfect performance of respiration, acts like a narcotic poison upon the brain; and no sooner, therefore, does it extend its malign influence to that organ, than deleterious effects are produced, and the animal, after apparent recovery, falls into a state of stupor, the pupils of the eyes become dilated, the respiration laborious, the muscles of the body convulsed, and it speedily dies, _poisoned by its own blood_. we are much indebted to mr. brodie for a series of experiments in confirmation of these views; and a very interesting case occurred some time since, in the neighbourhood of windsor, which is well calculated for their illustration. a corporal in the guards, whose name, if i am not mistaken, was schofield, was seized with cramp as he was bathing in the thames, and remained for several minutes under water. by judicious assistance, however, he was recovered, and appeared to those about him to be free from any danger, when he was attacked by convulsions and expired. had the respiration been artificially supported at this period, so as to have maintained the action of the heart until the black blood had returned from the brain, the life of the soldier might possibly have been saved. in the experiment which has given origin to these reflections, davy distinctly states, that after having recovered from the _primary_ effects of the carburetted hydrogen gas, and taken a walk with his friend mr. tobin, he was again seized with violent giddiness, attended with nausea and loss of sensation. the imperfectly oxygenized or dark-coloured blood had evidently affected the brain, and his life, at this period, was probably in greater jeopardy than in any other stage of the experiment. nothing daunted by the dangers to which the preceding experiments had exposed him, davy did not allow more than a week to elapse before he attempted to respire _fixed air_, or _carbonic acid gas_; but it was in vain that he made voluntary efforts to draw it into the windpipe; for, the moment the epiglottis was raised a little, such a painful irritation was induced as instantly to close it spasmodically on the glottis; and thus, in repeated trials, was he prevented from taking a single particle of carbonic acid into the lungs. when, however, the gas was diluted with a little more than double its volume of common air, he was enabled to breathe it for nearly a minute, when it produced a slight degree of giddiness, and an inclination to sleep.[ ] [ ] it would thus appear that carbonic acid, in its most concentrated form, may kill by exciting a spasmodic action, in which the epiglottis is closed, and the entrance of air into the lungs altogether prevented. in a diluted form, it may destroy by its specific influence upon the blood, which would seem to be of a highly sedative character. death produced by such an agent is probably attended with little or no suffering. the younger berthollet destroyed his life by inclosing himself in an atmosphere of this description; and on commencing his fatal experiment, he registered all the successive feelings he experienced, which were such as would have been occasioned by a narcotic:--a pause, and then an almost illegible word occurred: it is presumed that the pen dropped from his hand,--and he was no more. it may perhaps appear extraordinary to the reader of the "researches," that although they were published not more than eighteen months after the appearance of his "essays on heat and light," no allusion is made in them either to his theory or to his new nomenclature. in relating his experiments upon respiration, he employs the conventional language of the schools, and the word "_phos-oxygen_" does not once occur in the volume. this is fully explained in a communication made by him to mr. nicholson, and which was printed in his journal a short time after the publication of his essays in the west country contributions; in which he says,--"as facts have occurred to me with regard to the decomposition of bodies, which i had supposed to contain light, without any luminous appearance, i beg to be considered as a _sceptic_ with respect _to my own_ particular theory of the combinations of light, until i shall have satisfactorily explained those anomalies by fresh experiments. on account of this scepticism, and for other reasons, i shall in future use the common nomenclature; excepting that, as my discoveries concerning the gaseous oxide would render it highly improper to call a principle, which in one of its combinations is capable of being absorbed by venous blood, and of increasing the powers of life, _azote_,--i shall name it, with dr. pearson, chaptal, and others, nitrogene; and the _gaseous oxide of azote_ i shall call nitrous oxide." the same feeling is expressed at the conclusion of his third research.--"it would be easy to form theories referring the action of blood impregnated with _nitrous oxide_, to its power of supplying the nervous and muscular fibre with such proportions of condensed nitrogen, oxygen, light, or ethereal fluid, as enabled them more rapidly to pass through those changes which constitute their life; but we are unacquainted with the composition of dead organized matter; and new instruments of experiment, and new modes of research, must be found, before we can ascertain even our capabilities of discovering the laws of life." there is one circumstance connected with the views entertained in this work which must not be passed over without notice. in several passages he advocates the theory of the atmosphere being a _chemical compound_ of oxygen and nitrogen; whereas, in later years, he was amongst the first to insist upon its being simply a mechanical mixture of these gases. in consequence of the highly deleterious experiments which have been already described, and of the constant labours of the laboratory, and the repeated inhalation of acid and other vapours, his health began visibly to decline, and he retired into cornwall, where he informs us that "the associations of ideas and feelings, common exercise, a pure atmosphere, luxurious diet, and a moderate indulgence in wine, in the course of a month, restored him to health and vigour." i find an allusion to this visit in a letter from his sister. "he had," she says, "written to his mother of his intention to visit her, but before the post had quitted bristol, he was already on his way to penzance, and would have reached it before his letter, had not his aunt, on whom he called in the neighbouring town of marazion, struck with his appearance of ill health, insisted on his remaining there till the next day, lest his mother should be doubly alarmed at his unexpected visit and altered looks." miss davy adds, "this one fact will serve, at the same time, to illustrate his attachment to home, and the impetuosity of his mind, which never rested till the object he proposed was accomplished." the following letter is inserted in this place, for the purpose of fixing the period at which he first ascertained those new facts in voltaic electricity, which formed the basis of a future communication to the royal society, and which may be said to have paved the way to his grand discoveries in that branch of science;--the dawning of that glorious day, which we shall presently view in all its splendour and glory. there is, moreover, something extremely interesting in receiving from himself a simple and unadorned statement of results, as they successively presented themselves to his observation--"truths plucked as they are growing, and delivered to you before their dew is brushed off." to davies giddy, esq. pneumatic institution, october , . be assured, my respected friend, that your last letter, though short, was highly gratifying to me. at the moment it was brought to me, i was about to depart with king and danvers on an excursion to the banks of the wye. our design was to see tintern abbey by moonlight, and it was perfectly accomplished. after viewing for three hours all the varieties of light and shade which a bright full moon and a blue sky could exhibit in this beautiful ruin, and after wandering for three days among the many-coloured woods and rocks surrounding the river between monmouth and chepstow, we arrived on the fourth day at bristol, having to balance against the pleasure of the tour, the fatigue of a stormy voyage down the wye, across the mouth of the severn, and up the avon. on analysing, after our return, specimens of the air collected from monmouth, from the woods on the banks of the wye, and from the mouth of the severn, there was no perceptible difference; they were all of similar composition to the air in the middle of bristol; that is, they contained about twenty-two per cent. of oxygen. the air from the bladders of some sea-weed, apparently just cast on shore, at the old passage, likewise gave the same results; so that, comparing these experiments with those made by cavendish, berthollet, &c. and by myself on other occasions, at different temperatures, in different weather, and with different winds, i am almost convinced that the whole of the lower stratum of the atmosphere is of uniform composition. no test can be more fallacious and imperfect than nitrous gas, on account of the different composition of nitrous acid, formed in the different manipulations of eudiometrical experiments. the eudiometer that i have lately employed gives, in a few minutes, the proportions of oxygen without correction. in pursuing experiments on galvanism, during the last two months, i have met with unexpected and unhoped-for success. some of the new facts on this subject promise to afford instruments capable of destroying the mysterious veil which nature has thrown over the operations and properties of ethereal fluids. galvanism i have found, by numerous experiments, to be a _process purely chemical_, and to depend wholly on the oxidation of metallic surfaces, having different degrees of electric conducting power. zinc is incapable of decomposing _pure_ water; and if the zinc plates be kept moist with _pure_ water, the galvanic pile does not act; but zinc is capable of oxidating itself when placed in contact with water, holding in solution either oxygen, atmospheric air, or nitrous or muriatic acid, &c.: and under such circumstances, the galvanic phenomena are produced, and their intensity is in proportion to the rapidity with which the zinc is oxidated. the galvanic pile only acts for a few minutes, when introduced into hydrogen, nitrogen, or hydro-carbonate; that is, only as long as the water between its plates holds some oxygen in solution: immerse it for a few moments in water containing air, and it acts again. it acts very vividly in oxygen gas, and less so in the atmosphere. when its plates are moistened by marine acid, its action is very powerful, but infinitely more so when nitrous acid is employed. five plates with nitrous acid gave sparks equal to those of the common pile. from twenty plates the shock was insupportable. i had almost forgotten to mention, that charcoal is a good galvanic exciter, and decomposes water, like the metals, in the pile; but i must stop, without being able to expatiate on the connection which is now obvious between galvanism and some of the phenomena of organic motion. i never consider the subject without having forcibly impressed upon my imagination your observations[ ] on the science of the ethereal fluids, and i cannot help flattering myself that this age will see your predictions verified. i remain with sincere respect and affection, yours, humphry davy. [ ] on conversing with mr. gilbert on the above passage, i understand that it is an allusion to his opinion, that the discovery of galvanic power would ultimately lead to a knowledge of the nature of light and heat. that a work, of the character of the "researches," replete with ingenious novelty, and rich in chemical discovery, proceeding from the pen of so young a man, should have excited very general admiration in the philosophic world, is a circumstance that cannot surprise us; but in a majority of cases, precocious merit enjoys only an ephemeral popularity; the sensations it excites are too vivid to be permanent, and the individual sinks into an obscurity rendered ten times more profound by the brilliancy of the flash which preceded it; but every event of davy's life would appear as if created, and directed for his welfare, by some presiding genius, whose activity, in throwing opportunities in his way was rivalled only by the address with which he converted them to his advantage. fortune and talent, then, were both equally engaged in accomplishing the elevation of davy, and it is probable that eminent success generally requires a combination of these elements for its production, and that the maxim of plautus is therefore as remote from truth as that of theophrastus, the one assigning all to fortune, the other all to talent. the experiments to which allusions have been frequently made during the present chapter, favourably as they were received, might have shared the fate of many other discoveries which did not admit of an immediate and obvious application to the purposes of common life; for statistical value is a necessary passport to popular favour. fortunately, however, for davy, before the vivid impression produced by his new work had lost the glow of novelty, count rumford was anxiously seeking for some rising philosopher, who might contribute his energies towards the support, and farther increase, of the chemical fame of the recently established "institution of great britain." it is not surprising that his attention should have been readily directed to one whose genius had been so lately displayed, and whose views regarding caloric[ ] were in such exact conformity with his own opinions. [ ] mr. gilbert no sooner discovered the tendency of davy's opinions respecting the immateriality of caloric, than he urged him to communicate them to count rumford, but he considered himself pledged to dr. beddoes, and his essays were accordingly printed in the west country contributions. count rumford, it may be observed, maintained that caloric, like _phlogiston_, was merely a creature of the chemist's imagination, and had no real existence. he considered heat as nothing more than the motions of the constituent particles of bodies amongst themselves,--an hypothesis which has no claims to novelty, being perhaps one of the most ancient on record.--see his paper on heat, _phil. trans._ for . as the philosophical public must feel a lively interest in every incident connected with a transaction so important to the interests of science, as that by which davy was placed in the chemical chair of the institution, i am fortunate in being able, through the kindness of his two friends, mr. thomson and mr. underwood, to present a clear and satisfactory statement of all its circumstances and details. chapter iii. count rumford negotiates with mr. underwood on the subject of davy's appointment to the royal institution.--terms of his engagement communicated in a letter to mr. gilbert.--davy arrives, and takes possession of his apartments.--he receives various mortifications.--he is elected a member of the tepidarian society.--is appointed lecturer instead of assistant.--he makes a tour in cornwall with mr. underwood.--anecdotes.--his poem on spinosism.--his letter to mr. gilbert, communicating a galvanic discovery.--he commences his first grand course of lectures.--his brilliant success.--a letter from mr. purkis.--davy's style criticised.--his extraordinary method of experimenting.--davy and wollaston compared as experimentalists.--the style of davy as a lecturer and a writer contrasted. it may be readily supposed that the prominent situation held by davy at bristol, as well as the merited celebrity of his writings, must have rendered his name familiar to all the leading philosophers of the day. it were vain, therefore, to enquire through what channel the echo of his fame first reached the ear of count rumford;[ ] it is sufficient to state that mr. underwood, a gentleman ardently attached to science, and devoted to the interests of the royal institution, was amongst the first to urge the expediency of inviting him to london as a public lecturer. mr. underwood, in a letter lately addressed to me from paris, says, "in consequence of several conversations with count rumford, on the subject of davy's superior talents, and the advantages that would accrue to the institution from engaging him as a lecturer, the count called upon me on the th of january , having received from the managers of the institution full powers to negotiate upon the subject. on this occasion, however, i thought it advisable to introduce the count to mr. james thomson, as being the more eligible person to treat in behalf of davy, not only on account of his greater intimacy with him, but because, not being a proprietor, he was unconnected with the interests of the institution." [ ] amongst other celebrated chemists who had become acquainted with davy at bristol, and subsequently spoken of his extraordinary genius, was dr. hope. he informs me that count rumford had applied to him to find some chemist who would undertake the office of lecturer at the institution; but that he failed in discovering such a person as he could, with propriety, introduce; some time afterwards, however, he became acquainted with davy, and having soon perceived his talents, recommended him without any hesitation to the patronage of the count. this circumstance, combined with several others, no doubt might have had its influence in deciding the fate of davy. mr. thomson, who saw the prospect of honour and emolument thus opened for his friend, after a satisfactory interview with count rumford, immediately wrote to davy, with an earnest recommendation that he should, without loss of time, come to town, and conclude an arrangement thus auspiciously commenced. davy, with his characteristic ardour, answered the letter in person. he was introduced to the managers, and the preliminary arrangements were soon completed; the nature of which is disclosed by himself in the following letter to mr. gilbert. hotwells, march , . i cannot think of quitting the pneumatic institution, without giving you intimation of it in a letter; indeed, i believe i should have done this some time ago, had not the hurry of business, and the fever of emotion produced by the prospect of novel changes in futurity, destroyed to a certain extent my powers of consistent action. you, my dear sir, have behaved to me with great kindness, and the little ability i possess you have very much contributed to develope; i should therefore accuse myself of ingratitude, were i to neglect to ask your approbation of the measures i have adopted with regard to the change of my situation, and the enlargement of my views in life. in consequence of an invitation from count rumford, given to me with some proposals relative to the royal institution, i visited london in the middle of february, where, after several conferences with that gentleman, i was invited by the managers of the royal institution to become the director of their laboratory, and their assistant professor of chemistry; at the same time i was assured that, within the space of two or three seasons, i should be made sole professor of chemistry, still continuing director of the laboratory. the immediate emolument offered was sufficient for my wants; and the sole and uncontrolled use of the apparatus of the institution, for private experiments, was to be granted me. the behaviour of count rumford, sir joseph banks, mr. cavendish, and the other principal managers, was liberal and polite; and they promised me any apparatus that i might need for new experiments. the time required to be devoted to the services of the institution was but short, being limited chiefly to the winter and spring. the emoluments to be attached to the office of sole professor of chemistry are great; and, above all, the situation is permanent, and held very honourable. these motives, joined to the approbation of dr. beddoes, who with great liberality has absolved me from my engagements at the pneumatic institution, and the strong wishes of most of my friends in london and bristol, determined my conduct. thus i am quickly to be transferred to london, whilst my sphere of action is considerably enlarged, and as much power as i could reasonably expect, or even wish for at my time of life, secured to me without the obligation of labouring at a profession. the royal institution will, i hope, be of some utility to society. it has undoubtedly the capability of becoming a great instrument of moral and intellectual improvement. its funds are very great. it has attached to it the feelings of a great number of people of fashion and property, and consequently may be the means of employing, to useful purposes, money which would otherwise be squandered in luxury, and in the production of unnecessary labour. count rumford professes that it will be kept distinct from party politics; i sincerely wish that such may be the case, though i fear it.[ ] as for myself, i shall become attached to it full of hope, with the resolution of employing all my feeble powers towards promoting its true interests. so much of my paper has been given to pure egotism, that i have but little room left to say any thing concerning the state of science, and the public mind in town; unfortunately, there is little to say. i have heard of no important discoveries. in politics, nothing seems capable of exciting permanent interest. the stroke of poverty, though severely felt, has been a torpedo, benumbing all energy, and not irritating and awakening it, as might have been expected. here, at the pneumatic institution, the nitrous oxide has evidently been of use. dr. beddoes is proceeding in the execution of his great popular physiological work, which, if it equals the plan he holds out, ought to supersede every work of the kind. i have been pursuing galvanism with labour, and some success. i have been able to produce galvanic power from simple plates, by effecting on them different oxidating and deoxidating processes; but on this point i cannot enlarge in the small remaining space of paper. your remark concerning _negative_ galvanism, and deoxidation, is curious, and will most probably hold good. it will give me much pleasure to see your mathematical paper[ ] in the philosophical transactions, but it will be, unfortunately, to me the pleasure of _blind_ sympathy, though derived from the consciousness that you ought to be acting upon, and instructing the world at large. it will give me sincere pleasure to hear from you, when you are at leisure. after the th i shall be in town--my direction, royal institution, albemarle street. i am, my dear friend, with respect and affection, yours, humphry davy. [ ] in england, politics so constantly mix themselves up with all our institutions, while science unfortunately finds so few disciples and patrons in the ranks of aristocracy, that every new society is viewed with jealousy and party spirit. johnson says, in his life of addison--"it has been suggested that the royal society was instituted soon after the restoration, to divert the attention of the people from public discontent."--p. [ ] he alludes to some calculations connected with light, and the imponderable fluids. the first notice of davy's name, in the minute book of the royal institution, occurs in the report adopted at a meeting of the managers, on monday the th of february . "resolved--that mr. humphry davy be engaged in the service of the royal institution, in the capacities of assistant lecturer in chemistry, director of the laboratory, and assistant editor of the journals of the institution, and that he be allowed to occupy a room in the house, and be furnished with coals and candles; and that he be paid a salary of one hundred guineas per annum." on the th of march , after reporting that "a room had been prepared and furnished for davy," the minute proceeds to state that "mr. davy had arrived at the institution on wednesday the th of march, and taken possession of his situation." it is a curious fact, that the first impression produced on count rumford by davy's personal appearance, was highly unfavourable to the young philosopher, and he expressed to mr. underwood his great regret at having been influenced by the ardour with which his suit had been urged; and he actually would not allow him to lecture in the theatre, until he had given a specimen of his abilities in the smaller lecture-room. his first lecture, however, entirely removed every prejudice which had been formed; and at its conclusion the count emphatically exclaimed--"let him command any arrangements which the institution can afford." he was accordingly, on the very next day, promoted to the great theatre. davy's uncouth appearance and address subjected him to many other mortifications on his first arrival in london. there was a smirk on his countenance, and a pertness in his manner, which, although arising from the perfect simplicity of his mind, were considered as indicating an unbecoming confidence. johnson, the publisher, as many of my readers will probably remember, was in the custom of giving weekly dinners to the more distinguished authors and literary stars of the day. davy, soon after his appointment, was invited upon one of these occasions, but the host actually considered it necessary to explain, by way of apology, to his company, the motives which had induced him to introduce into their society a person of such humble pretensions. at this dinner a circumstance occurred, which must have been very mortifying to the young philosopher. fuseli was present, and, as usual, highly energetic upon various passages of beauty in the poets, when davy most unfortunately observed, that there were passages in milton which he could never understand. "very likely, very likely, sir," replied the artist in his broad german accent, "but i am sure that is not milton's fault." on the th of april, he was elected a member of a society which consisted of twenty-five of the most violent republicans of the day; it was called the "_tepidarian_ society," from the circumstance of nothing but tea being allowed at their meetings, which were held at old slaughter's coffee house in saint martin's lane. to the influence of this society, mr. underwood states that davy was greatly indebted for his early popularity. fame gathers her laurels with a slow hand, and the most brilliant talents require a certain time for producing a due impression upon the public; the _tepidarians_ exerted all their personal influence to obtain an audience before the reputation of the lecturer could have been sufficiently known to attract one. although the acquaintance between davy and count rumford commenced so inauspiciously, they very soon became friends, and mutually entertained for each other the highest regard. davy's improved manners and naturally simple habits, at this period, were highly interesting and exemplary: towards his old friends he conducted himself with the greatest amenity, and frequently consulted them upon certain points connected with his new station in society. the following anecdote was communicated by mr. underwood.--"i introduced him," says he, "to my old friend, the excellent sir henry englefield, who was the first intimate acquaintance davy had formed in the higher circles; he was received by him with all that warmth of manner, and kindness of feeling, which so eminently distinguished him. shortly after this introduction, sir harry sent him an invitation to meet me at dinner. davy found himself unable to frame an answer to his satisfaction, and fearing he might betray his ignorance of etiquette, ran to my house, and greatly alarmed my mother by the extreme anxiety he displayed, and the manner in which he entreated her to send me to him the moment i returned. i went and found him cudgelling his brains to produce this first attempt at fashionable composition; a dozen answers were on his table, and he was in the highest degree excited and annoyed." it would appear that, immediately after his arrival at the royal institution, he entered upon the duties of his station, and performed them so greatly to the satisfaction of the managers, that, at a meeting held on the first of june, not more than six weeks afterwards, the following resolutions were passed. "resolved--that mr. humphry davy, director of the chemical laboratory, and assistant lecturer in chemistry, has, since he has been employed at the institution, given satisfactory proofs of his talents as a lecturer. "resolved--that he be appointed, and in future denominated, lecturer in chemistry at the royal institution, instead of continuing to occupy the place of _assistant_ lecturer, which he has hitherto filled." from an examination of the minute book, it appears that dr. garnett, whose health had long been on the decline, resigned his professorship on the th of june,[ ] and that on the th of july in the same year, dr. young was engaged as professor of natural philosophy, editor of the journals, and general superintendent of the house, at the salary of _l._ per annum. [ ] he delivered his farewell lecture on the th of the same month. with dr. garnett he had lived on terms of great intimacy; with his successor he associated with less ease and freedom. at a meeting of the managers, also held in july, several resolutions were passed to the following effect. "resolved--that a course of lectures on the chemical principles of the art of tanning be given by mr. davy. to commence the second of november next; and that respectable persons of the trade, who shall be recommended by proprietors of the institution, be admitted to these lectures gratis. "resolved further--that mr. davy have permission to absent himself during the months of july, august, and september, for the purpose of making himself more particularly acquainted with the practical part of the business of tanning, in order to prepare himself for giving the above-mentioned course of lectures." davy, it would appear, availed himself of the permission granted to him by the above resolution of the managers, and during the interval visited his native country. he had arranged with his friend underwood to make a tour through cornwall; but as it was his wish to remain at bristol for a few days, on his way to the west, it was agreed between them that they should meet at penzance. davy, however, became impatient, and wrote the following letter to his friend, a composition of much wildness, and obnoxious to the suspicion of spinosism. my dear underwood, that part of almighty god which resides in the rocks and woods, in the blue and tranquil sea, in the clouds and sunbeams of the sky, is calling upon thee with a loud voice: religiously obey its commands, and come and worship with me on the ancient altars of cornwall. i shall leave bristol on thursday next, possibly before, so that by this day week i shall probably be at penzance. ten days or a fortnight after, i shall expect to see you, and to rejoice with you. we will admire together the wonders of god,--rocks and the sea, dead hills and living hills covered with verdure. amen. write to me immediately, and say when you will come. direct h. davy, penzance. farewell, being of energy! your's with unfeigned affection, h. davy. mr. underwood transmitted to me the above letter with the following extract from his journal. "on the th i went to bristol, and on the th arrived at mrs. davy's at penzance. on the st of august we set off on a pedestrian excursion, and proceeded along the edge of the cliffs, round the land's end, cape cornwall, saint just, and saint ives, to redruth, and thence back to penzance. "two days afterwards we again started, and trudged along the shore to the lizard. kynance cove had from the commencement of our intimacy been a daily theme of his conversation. no epithets were sufficiently forcible to express his admiration at the beauty of the spot: the enthusiastic delight with which he dwelt upon the description of the serpentine rocks, polished by the waves, and reflecting the brightest tints from their surfaces, seemed inexhaustible, and when we had arrived at the spot he appeared absolutely entranced. "during these excursions his conversation was most romantic and poetical. his views of nature, and her sublime operations, were expressed without reserve, as they rapidly presented themselves to his imagination: they were the ravings of genius; but even his nonsense was that of a superior being." at the village of mullion, a little incident occurred, which evinced the existence of that gastronomic propensity which, in after years, displayed itself in a wider range of operations. the tourists had, on their road, purchased a fine large bass of a fisherman, with the intention of desiring the landlady to dress it. on arriving at the inn, mr. underwood retired into a room for the purpose of making some notes in the journal he regularly kept. davy had disappeared. in the course of a few minutes a most tremendous uproar was heard in the kitchen, and the indignant vociferations of the hostess, which, even with all the advantages of cornish recitative, was not of the most melodious description, became fearfully audible. davy, it seems, had volunteered his assistance in making the sauce and stuffing for the aforesaid bass; and had he not speedily retreated, his services would have been rewarded, not according to the scientific practice of appending a string of letters to his name, but in conformity with the equally ancient custom of attaching a certain dishonourable addition to the skirts of his jacket. i have observed that his letter to mr. underwood betrayed a tincture of _spinosism_. it may be here remarked, that during the year he composed a poem, which he arbitrarily distinguished by that appellation, singularly opposed to the tenor of the sentiments. through the kindness of mr. greenough i possess a copy of it in its original state, for it was subsequently altered, and published in a collection, edited by miss johanna baillie; and still more recently, it underwent farther corrections, and was printed for private circulation in the form in which i shall here introduce it. lo! o'er the earth the kindling spirits pour the flames of life, that bounteous nature gives; the limpid dew becomes the rosy flower; the insensate dust awakes, and moves, and lives. all speaks of change: the renovated forms of long forgotten things arise again. the light of suns, the breath of angry storms, the everlasting motions of the main; these are but engines of the eternal will, the one intelligence; whose potent sway has ever acted, and is acting still, whilst stars, and worlds, and systems, all obey: without whose power, the whole of mortal things were dull, inert, an unharmonious band; silent as are the harp's untuned strings without the touches of the poet's hand. a sacred spark, created by his breath, the immortal mind of man his image bears; a spirit living midst the forms of death, oppress'd but not subdued by mortal cares-- a germ, preparing in the winter's frost, to rise and bud and blossom in the spring; an unfledged eagle by the tempest tost, unconscious of his future strength of wing:-- the child of trial, to mortality, and all its changeful influences given: on the green earth decreed to move and die; and yet by such a fate prepared for heaven.-- soon as it breathes, to feel the mother's form of orbed beauty, through its organs thrill; to press the limbs of life with rapture warm, and drink of transport from a living rill: to view the skies with morning radiance bright, majestic mingling with the ocean blue, or bounded by green hills, or mountains white; or peopled plains of rich and varied hue: the nobler charms astonish'd to behold of living loveliness, to see it move, cast in expression's rich and varied mould, awakening sympathy, compelling love:-- the heavenly balm of mutual hope to taste, soother of life; affection's bliss to share, sweet as the stream amidst the desert waste, as the first blush of arctic daylight fair:-- to mingle with its kindred, to descry the path of power--in public life to shine; to gain the voice of popularity; the idol of to-day, the man divine:-- to govern others by an influence strong as that high law, which moves the murm'ring main; raising and carrying all its waves along, beneath the full-orb'd moon's meridian reign:-- to scan how transient is the breath of praise; a winter's zephyr trembling on the snow, chill'd as it moves; or as the northern rays, first fading in the centre, whence they flow:-- to live in forests mingled with the whole of natural forms, whose generations rise in lovely change, in happy order roll on land, in ocean, in the glittering skies:-- their harmony to trace--the eternal cause to know in love, in reverence to adore-- to bend beneath the inevitable law, sinking in death; its human strength no more:-- then, as awakening from a dream of pain, with joy its mortal feelings to resign; yet all its living essence to retain, the undying energy of strength divine: to quit the burdens of its earthly days, to give to nature all her borrow'd powers; ethereal fire to feed the solar rays, ethereal dew to glad the earth in showers. the following letter was written from london, after his return from his cornish excursion. to davies giddy, esq. royal institution, nov. , . my dear sir, after leaving cornwall in august, i spent about three weeks in bristol, and at stowey, so that i did not arrive in london until the th of september. on my arrival i found that count rumford had altered his plans of absence, and had left london on that very day for the continent, purposing to return in about two months. he is now at paris, and in about a fortnight we expect him here. i shall soon have an opportunity of submitting captain trevitheck's boiler to his observation, and in my next letter i shall give you his opinion of it. you of course have read an account of dr. herschel's experiments on the heat-making rays; from some late observations it appears, that there are other invisible rays beyond the violet ones, possessed of the _chemical_ agency of light. sennebier ascertained some time ago that the violet rays blackened muriate of silver in three seconds; whereas the red rays required, for this effect, twenty minutes. ritter and dr. wollaston have found that beyond the violet rays there is exerted a strong deoxidating action. muriate of silver placed in the spectrum is not altered beyond the red rays; but it is instantly blackened when placed on the outside of the violet rays. i purpose to try whether the invisible deoxidating rays will produce light, when absorbed by solar phosphorus. the most curious galvanic facts lately noticed, are the combustion of gold, silver, and platina. professor tromsdorf, by connecting the ends of a moderately strong battery with gold and silver leaf, produced the combustion of them with vivid light. in repeating the experiment on a thin slip of platina, i have produced the same effect. i yesterday ascertained rather an important fact, namely, that a galvanic battery may be constructed _without any metallic substance_! by means of ten pieces of well-burnt charcoal, nitrous acid, and water, arranged alternately in wine-glasses, i produced all the effects usually obtained from zinc, silver, and water. the bakerian lecture by dr. young, our lecturer on natural philosophy, is now reading before the royal society. he attempts to revive the doctrine of huygens and euler, that light depends upon undulations of an ethereal medium. his proofs (i.e. his presumptive proofs) are drawn from some strong and curious analogies he has discovered between light and sound. i shall strongly hope, now the peace has arrived, to see you soon in london, as you proposed a tour through the continent; indeed, you should fix your permanent residence in london, where alone you can do what you ought--instruct and delight numbers of improved men. i am, my friend, yours with unfeigned esteem and respect, humphry davy. although during davy had given some desultory lectures, his splendid career cannot be said to have commenced until the following year, when on the st of january he delivered his introductory lecture to a crowded and enlightened audience in the theatre of the royal institution; which was afterwards printed at the request of a respectable proportion of the society. it contains a masterly view of the benefits to be derived from the various branches of science. he represents the chemist as the ruler of all the elements that surround us, and which he employs either for the satisfaction of his wants, or the gratification of his wishes. not contented with what is to be found on the surface of the earth, he describes him as penetrating into her bosom, and even of searching the depths of the ocean, for the purpose of allaying the restlessness of his desires, or of extending and increasing the boundaries of his power. in examining the science of chemistry, with regard to its great agency in the improvement of society, he offers the following almost prophetic remarks. "unless any great physical changes should take place upon the globe, the permanency of the arts and sciences is rendered certain, in consequence of the diffusion of knowledge, by means of the invention of printing; and by which those words which are the immutable instruments of thought, are become the constant and widely diffused nourishment of the mind, and the preservers of its health and energy. "individuals influenced by interested motives or false views, may check for a time the progress of knowledge;--moral causes may produce a momentary slumber of the public spirit;--the adoption of wild and dangerous theories, by ambitious or deluded men, may throw a temporary opprobrium on literature; but the influence of true philosophy will never be despised; the germs of improvement are sown in minds, even where they are not perceived; and sooner or later, the spring-time of their growth must arrive. "in reasoning concerning the future hopes of the human species, we may look forward with confidence to a state of society, in which the different orders and classes of men will contribute more effectually to the support of each other than they have hitherto done. this state, indeed, seems to be approaching fast; for, in consequence of the multiplication of the means of instruction, the man of science and the manufacturer are daily becoming more assimilated to each other. the artist, who formerly affected to despise scientific principles, because he was incapable of perceiving the advantages of them, is now so far enlightened as to favour the adoption of new processes in his art, whenever they are evidently connected with a diminution of labour; and the increase of projectors, even to too great an extent, demonstrates the enthusiasm of the public mind in its search after improvement. "the arts and sciences, also, are in a high degree cultivated and patronized by the rich and privileged orders. the guardians of civilization and of refinement, the most powerful and respected part of society, are daily growing more attentive to the realities of life,--and giving up many of their unnecessary enjoyments, in consequence of the desire to be useful, are becoming the friends and protectors of the labouring part of the community. "the unequal division of property and of labour, the differences of rank and condition amongst mankind, are the sources of power in civilized life--its moving causes, and even its very soul. in considering and hoping that the human species is capable of becoming more enlightened and more happy, we can only expect that the different parts of the great whole of society should be intimately united together, by means of knowledge and the useful arts; that they should act as the children of one great parent, with one determinate end, so that no power may be rendered useless--no exertions thrown away. "in this view, we do not look to distant ages, or amuse ourselves with brilliant though delusive dreams, concerning the infinite improveability of man, the annihilation of labour, disease, and even death, but we reason by analogy from simple facts, we consider only a state of human progression arising out of its present condition,--we look for a time that we may reasonably expect--for a bright day, of which we already behold the dawn." the extraordinary sensation produced amongst the members of the institution by this first course of lectures, has been vividly described by various persons who had the good fortune to be his auditors; and foreigners have recorded in their travels the enthusiasm with which the great english chemist had inspired his countrymen. the members of the tepidarian society, sanguine in the success of their child,--for so they considered davy,--purposely appointed their anniversary festival on the day of his anticipated triumph. they were not disappointed in their hopes; and their dinner was marked by every demonstration of hilarity. in the evening, davy accompanied by a few friends, attended, for the first time in his life, a masquerade which was given at ranelagh. on the following day, he dined with sir harry englefield. i have a copy of the invitation, addressed to mr. underwood, now before me. dear underwood, davy, covered with glory, dines with me to-day at five. if you could meet him, it would give me great pleasure. tilney street, friday. yours truly, h. c. englefield. at this dinner, sir harry wrote a request to davy to print his lecture, which was signed by every one present, except mr. underwood, who declined, from the apprehension that the signature of so intimate a friend might give to that which was a spontaneous homage to talent, the appearance of a previously concerted scheme. i shall here weave into my narrative some extracts from several letters, with which mr. purkis, one of the earliest friends of davy, has lately favoured me. "on his first appointment at the royal institution, i was specially introduced to him by a common friend, thomas poole, esq. of nether stowey in somersetshire; and i continued in habits of friendship with him during a great portion of his life, though somewhat less intimately during the last few years. i loved him living--i lament his early death: i shall ever honour his memory. "the sensation created by his first course of lectures at the institution, and the enthusiastic admiration which they obtained, is at this period scarcely to be imagined. men of the first rank and talent,--the literary and the scientific, the practical and the theoretical, blue-stockings, and women of fashion, the old and the young, all crowded--eagerly crowded the lecture-room. his youth, his simplicity, his natural eloquence, his chemical knowledge, his happy illustrations and well-conducted experiments, excited universal attention and unbounded applause. compliments, invitations, and presents, were showered upon him in abundance from all quarters; his society was courted by all, and all appeared proud of his acquaintance. "one instance of attention is particularly recalled to my memory. a talented lady, since well known in the literary world, addressed him anonymously in a poem of considerable length, replete with delicate panegyric and genuine feeling. it displayed much originality, learning, and taste: the language was elegant, the versification harmonious, the sentiments just, and the imagery highly poetical. it was accompanied with a handsome ornamental appendage for the watch, which he was requested to wear when he delivered his next lecture, as a token of having received the poem, and pardoned the freedom of the writer. it was long before the fair authoress was known to him, but they afterwards became well acquainted with each other." i should not redeem the pledge given to my readers, nor fulfill the duties of an impartial biographer, were i to omit acknowledging that the manners and habits of davy very shortly underwent a considerable change. let those who have vainly sought to disparage his excellence, enjoy the triumph of knowing that he was not perfect; but it may be asked in candour, where is the man of twenty-two years of age, unless the temperature of his blood were below zero, and his temperament as dull and passionless as the fabled god of the brahmins, who could remain uninfluenced by such an elevation? look at davy in the laboratory at bristol, pursuing with eager industry various abstract points of research; mixing only with a few philosophers, sanguine like himself in the investigation of chemical phenomena, but whose sphere of observation must have been confined to themselves, and whose worldly knowledge could scarcely have extended beyond the precincts of the institution in which they were engaged. shift the scene--behold him in the theatre of the royal institution, surrounded by an aristocracy of intellect as well as of rank; by the flowers of genius, the _élite_ of fashion, and the beauty of england, whose very respirations were suspended in eager expectation to catch his novel and satisfactory elucidations of the mysteries of nature. could the author of the rambler have revisited us, he would certainly have rescinded the passage in which he says--"all appearance of science is hateful to women; and he who desires to be well received by them, must qualify himself by a total rejection of all that is rational and important; must consider learning as perpetually interdicted, and devote all his attention to trifle, and all his eloquence to compliment." it is admitted that his vanity was excited, and his ambition raised, by such extraordinary demonstrations of devotion; that the bloom of his simplicity was dulled by the breath of adulation; and that, losing much of the native frankness which constituted the great charm of his character, he unfortunately assumed the garb and airs of a man of fashion; let us not wonder if, under such circumstances, the inappropriate robe should not always have fallen in graceful draperies. at length, so popular did he become, under the auspices of the duchess of gordon and other leaders of high fashion, that even their _soirées_ were considered incomplete without his presence; and yet these fascinations, strong as they must have been, never tempted him from his allegiance to science: never did the charms of the saloon allure him from the pursuits of the laboratory, or distract him from the duties of the lecture-room. the crowds that repaired to the institution in the morning were, day after day, gratified by newly devised and highly illustrative experiments, conducted with the utmost address, and explained in language at once perspicuous and eloquent. he brought down science from those heights which were before accessible only to a few, and placed her within the reach of all; he divested the goddess of all severity of aspect, and represented her as attired by the graces. it is perhaps not possible to convey a better idea of the fascination of his style, than by the relation of the following anecdote. a person having observed the constancy with which mr. coleridge attended these lectures, was induced to ask the poet what attractions he could find in a study so unconnected with his known pursuits. "i attend davy's lectures," he replied, "to increase my stock of metaphors." but, as johnson says, in the most general applause some discordant voices will always be heard; and so was it upon the present occasion. it was urged by several modern _zoili_, that the style was far too florid and imaginative for communicating the plain lessons of truth; that he described objects of natural history by inappropriate imagery, and that violent conceits frequently usurped the place of philosophical definitions. this was boeotian criticism; the attic spirits selected other points of attack: they rallied him on the ground of affectation, and whimsically represented him as swayed by a mawkish sensibility, which constantly betrayed him into absurdity. there might be some show of justice in this accusation: the world was not large enough to satisfy the vulgar ambition of the conqueror, but the minutest production of nature afforded ample range for the scrutinizing intelligence of the philosopher; and he would consider a particle of crystal with so delicate a regard for its minute beauties, and expatiate with so tender a tone of interest on its fair proportions, as almost to convey an idea that he bewailed the condition of necessity which for ever allotted it so slender a place in the vast scheme of creation. after the observations which have been offered with regard to the injurious tendency of metaphors in all matters relating to science, i may probably be charged with inconsistency in defending davy from the attacks thus levelled against his style. we need not the critic to remind us that the statue of a lysippus may be spoiled by gilding; but i would observe that the style which cannot be tolerated in a philosophical essay, may under peculiar circumstances be not only admissible, but even expedient, in a popular lecture. "_neque ideo minus efficaces sunt orationes nostræ quia ad aures judicantium cum voluptate perveniunt. quid enim si infirmiora horum temporum templa credas, quia non rudi cæmento, et informibus tegulis exstruuntur; sed marmore nitent et auro radiantur?_" let us consider, for a moment, the class of persons to whom davy addressed himself. were they students prepared to toil with systematic precision, in order to obtain knowledge as a matter of necessity?--no--they were composed of the gay and the idle, who could only be tempted to admit instruction by the prospect of receiving pleasure,--they were children, who could only be induced to swallow the salutary draught by the honey around the rim of the cup. it has been well observed, that necessity alone can urge the traveller over barren heaths and snow-topped mountains, while he treads with rapture along the fertile vales of those happier climes where every breeze is perfume, and every scene a picture. if science can be promoted by increasing the number of its votaries, and by enlisting into its service those whom wealth and power may render valuable as examples or patrons, there does not exist a class of philosophers to which we are more largely indebted than to popular lecturers, or to those whose eloquence has clothed with interest, subjects otherwise severe and uninviting. how many disciples did mineralogy acquire through the lectures of dr. clarke at cambridge, who may truly be said to have covered a desert with verdure, and to have raised from barren rocks flowers of every hue and fragrance! in the sister university, what an accession of strength and spirit have the animated discourses of dr. buckland brought to the ranks of geologists! to judge fairly of the influence of a popular style, we should acquaint ourselves with the effects of an opposite method; and if an appeal be made to experience, i may very safely abide the issue. dr. young, whose profound knowledge of the subjects he taught, no one will venture to question, lectured in the same theatre, and to an audience similarly constituted to that which was attracted by davy, but he found the number of his attendants diminish daily, and for no other reason than that he adopted too severe and didactic a style.[ ] [ ] from the following minute it would appear, that dr. young's connection with the royal institution was but of short duration. it will be remembered that his appointment took place on july , . "resolved--that dr. young be paid the balance of two years' complete salary, and that his engagement with the institution terminate from this time--july , ." in speaking of davy's lectures as mere specimens of happy oratory, we do injustice to the philosopher. had he merely added the corinthian foliage to a temple built by other hands, we might have commended his taste, and admired his talent of adaptation, and there our eulogium must have ended; but the edifice itself was his own; he dug the materials from the quarry, formed them into a regular pile, and then with his masterly touch added to its strength beauty, and to its utility grace. in addition to these morning lectures, we find that he was also engaged in delivering a course in the evening; of which the following notice is extracted from one of the scientific journals of the time. "on the th, mr. davy commenced a course of lectures on galvanic phenomena. sir joseph banks, count rumford, and other distinguished philosophers, were present. the audience were highly gratified, and testified their satisfaction by general and repeated applause. "mr. davy, who appears to be very young, acquitted himself admirably. from the sparkling intelligence of his eye, his animated manner, and the _tout ensemble_, we have no doubt of his attaining a very distinguished eminence." from a minute entered on the records of the institution, it appears that, at a meeting of managers held on the st of may , it was moved by sir joseph banks, and seconded by mr. sullivan,-- "that mr. humphry davy be for the future styled _professor of chemistry_ to the royal institution." a sufficient proof of the universal feeling of admiration which his lectures had excited. the success of his exertions is communicated by him to his early friend, in the following letter. to davies giddy, esq. dear friend, since the commencement of the session at the institution, i have had but few moments of leisure. the composition of a first course of lectures, and the preparation for experiments, have fully occupied my time; and the anxieties and hopes connected with a new occupation have prevented me from paying sufficient attention even to the common duties and affections of life. under such circumstances, i trust you will pardon me for having suffered your letters to remain so long unanswered. in human affairs, anticipation often constitutes happiness: your correspondence is to me a real source of pleasure, and, believe me, i would suffer no opportunity to escape of making it more frequent and regular. my labours in the theatre of the royal institution have been more successful than i could have hoped from the nature of them. in lectures, the effect produced upon the mind is generally transitory; for the most part, they amuse rather than instruct, and stimulate to enquiry rather than give information. my audience has often amounted to four and five hundred, and upwards; and amongst them some promise to become permanently attached to chemistry. this science is much the fashion of the day. amongst the latest scientific novelties, the two new planets occupy the attention of astronomers, while natural philosophers and chemists are still employed upon galvanism. in a paper lately read before the royal society, dr. herschel examines the magnitudes of the bodies discovered by mr. piazzi and dr. olbers. he supposes the apparent diameter of ceres to be about ´´, and that of pallas, ´´ or ´´, so that their real diameters are , and or english miles--how small! the doctor thinks that they differ from planets in their general character, as to their diminutive size, the great inclination of their orbits, the coma surrounding them, and as to the proximity of their orbits.--from comets, in their want of their eccentricity, and any considerable nebulosity. he proposes to call them _asteroids_. i mentioned to you in a former letter the great powers of galvanism in effecting the combustion of metals. i have lately had constructed for the laboratory of the institution, a battery of immense size: it consists of four hundred plates of five inches in diameter, and forty, of a foot in diameter. by means of it, i have been enabled to inflame cotton, sulphur, resin, oil, and ether; it fuses platina wire, and makes red hot and burns several inches of iron wire of - th of an inch in diameter; it easily causes fluid substances, such as oil and water, to boil, decompounds them, and converts them into gases. i am now examining the agencies of it upon certain substances that have not as yet been decomposed, and in my next letter i hope to be able to give you an account of my experiments. i shall hope soon to hear that the roads of england are the haunts of captain trevitheck's dragons. you have given them a characteristic name. i wish any thing would happen to tempt you to visit london. you would find a number of persons very glad to see you, with whose attentions you could not be displeased. with unfeigned respect, yours sincerely, h. davy. it is perhaps not possible to imagine a greater contrast, than between the elegant manner in which davy conducted his experiments in the theatre, and the apparently careless and slovenly style of his manipulations in the laboratory: but in the one case he was communicating knowledge; in the other, obtaining it. mr. purkis relates an anecdote very characteristic of this want of refinement in his working habits. "on one occasion, while reading over to me an introductory lecture, and wishing to expunge a needless epithet, instead of taking up the pen, he dipped his forefinger into the ink-bottle, and thus blotted out the unmeaning expletive." it was his habit in the laboratory, to carry on several unconnected experiments at the same time, and he would pass from one to the other without any obvious design or order: upon these occasions he was perfectly reckless of his apparatus; breaking and destroying a part, in order to meet some want of the moment. so rapid were all his movements, that, while a spectator imagined he was merely making preparations for an experiment, he was actually obtaining the results, which were just as accurate as if a much longer time had been expended. with davy, rapidity was power. the rapid performance of intellectual operations was a talent which displayed itself at every period of his life. we have heard with what extraordinary rapidity he read at the age of five years; and we now learn that his chemical enquiries were conducted with similar facility and quickness. his early friend mr. poole bears his testimony to the existence of the same quality in the following passage, extracted from a letter i had lately the favour of receiving from him. "from my earliest knowledge of my admirable friend, i consider his most striking characteristic to have been the quickness and truth of his apprehension. it was a power of reasoning so rapid, when applied to any subject, that he could hardly be himself conscious of the process; and it must, i think, have been felt by him, as it appeared to me, pure intuition. i used to say to him, 'you understand me before i half understand myself?' "i recollect on our first acquaintance, he knew but little of the practice of agriculture. i was at that time a considerable farmer, and very fond of the occupation. during his visits in those days, i was at first something like his teacher, but my pupil soon became my master both in theory and practice." the chemical manipulations of wollaston and davy offered a singular contrast to each other, and might be considered as highly characteristic of the temperaments and intellectual qualities of these remarkable men. every process of the former was regulated with the most scrupulous regard to microscopic accuracy, and performed with the utmost neatness of detail. it has been already stated with what turbulence and apparent confusion the experiments of the latter were conducted; and yet each was equally excellent in his own style; and, as artists, they have not unaptly been compared to teniers and michael angelo. by long discipline, wollaston had acquired such power in commanding and fixing his attention upon minute objects, that he was able to recognise resemblances, and to distinguish differences, between precipitates produced by re-agents, which were invisible to ordinary observers, and which enabled him to submit to analysis the minutest particle of matter with success. davy, on the other hand, obtained his results by an intellectual process, which may be said to have consisted in the extreme rapidity with which he seized upon, and applied, appropriate means at appropriate moments. many anecdotes might be related in illustration of the curiously different structure of the minds of these two ornaments of british science. the reader will, in the course of these memoirs, be furnished with sufficient evidence of the existence of those qualities which i have assigned to davy; another biographer will no doubt ably illustrate those of dr. wollaston. i shall only observe, that to this faculty of minute observation, which dr. wollaston applied with so much advantage, the chemical world is indebted for the introduction of more simple methods of experimenting,--for the substitution of a few glass tubes, and plates of glass, for capacious retorts and receivers, and for the art of making grains give the results which previously required pounds. a foreign philosopher once called upon dr. wollaston with letters of introduction, and expressed an anxious desire to see his laboratory. "certainly," he replied; and immediately produced a small tray containing some glass tubes, a blow-pipe, two or three watch-glasses, a slip of platinum, and a few test bottles. wollaston appeared to take great delight in showing by what small means he could produce great results. shortly after he had inspected the grand galvanic battery constructed by mr. children, and had witnessed some of those brilliant phenomena of combustion which its powers produced, he accidentally met a brother chemist in the street, and seizing his button, (his constant habit when speaking on any subject of interest,) he led him into a secluded corner; when taking from his waistcoat pocket a tailor's thimble, which contained a galvanic arrangement, and pouring into it the contents of a small phial, he instantly heated a platinum wire to a white heat. there was another peculiarity connected with wollaston's habit of minute observation: it enabled him to press into his service, at the moment, such ordinary and familiar materials as would never have occurred to less observing chemists. mr. brande relates an anecdote admirably calculated to exemplify this habit. he had called upon dr. wollaston to consult him upon the subject of a calculus;--it will be remembered that neither phosphate of lime, constituting the '_bone earth_' species, nor the ammoniaco-magnesian phosphate, commonly called the '_triple phosphate_,' is _per se_ fusible; but that when mixed, these constitute the '_fusible calculus_' which readily melts before the blow-pipe. dr. wollaston, on finding the substance under examination refractory, took up his paper-folder, and scraping off a fragment of the ivory, placed it on the specimen, when it instantly fused.[ ] [ ] i have lately been informed that the idea of constructing an instrument like the camera lucida, first suggested itself to dr. wollaston, on his noticing certain phenomena occasioned by a crack in the glass before which he was shaving himself. having contrasted the manipulations of davy, as exhibited in the theatre, with those performed by him in the laboratory, it may, in this place, be interesting to offer a few remarks upon the difference of his style as a lecturer and as a writer. whatever diversity of opinion may have been entertained as to the former, i believe there never was but one sentiment with respect to the latter. there is an ethereal clearness of style, a simplicity of language, and, above all, a freedom from technical expression, which render his philosophical memoirs fit studies and models for all future chemists. mr. brande, in a late lecture delivered before the members of the royal institution, very justly alluded to this latter quality of his writings, and forcibly contrasted it with the system of berzelius, of whom it is painful to speak but in terms of the most profound respect, and yet it is impossible not to express a deep regret at this distinguished chemist's introduction of a system of technical expressions, which from its obscurity is calculated to multiply rather than to correct error, and from its complications, to require more labour than the science to which it administers: to apply the quaint metaphor of locke, "it is no more suited to improve the understanding, than the move of a jack is to fill our bellies." from the readiness with which some continental chemists have adopted such terms, and from the spirit in which they have defended them, one might almost be led to suspect that they believed them, like the words used by the magi of persia, to possess a cabalistic power. davy foresaw the injury which science must sustain from such a practice, and endeavoured, both by precept and example, to discountenance it. with regard to the introduction of a figurative and ornamental style into memoirs purely scientific, no one could entertain a more decided objection; and in his "last days," he warns us against the practice. "in detailing the results of experiments, and in giving them to the world, the chemical philosopher should adopt the simplest style and manner; he will avoid all ornaments, as something injurious to his subject, and should bear in mind the saying of the first king of great britain, respecting a sermon which was excellent in doctrine, but overcharged with poetical allusions and figurative language,--'that the tropes and metaphors of the speaker were like the brilliant wild flowers in a field of corn, very pretty, but which did very much hurt the corn.'" chapter iv. davy makes a tour with mr. purkis, through wales.--beautiful phenomenon observed from the summit of arran benllyn.--letter to mr. gilbert.--journal of the institution.--davy's papers on eudiometry, and other subjects.--his first communication to the royal society, on a new galvanic pile.--he is proposed as a fellow, and elected into the society.--his paper on astringent vegetable substances, and on their operation in tanning leather.--his letter to mr. poole.--he is appointed chemical lecturer to the board of agriculture.--he forms friendships with the duke of bedford, mr. coke, and many other celebrated agriculturists.--attends the sheep-shearing at holkham and woburn.--composes a prologue to the "honey-moon." after the fatigues and anxieties of his first session, davy sought relaxation and repose amidst the magnificent scenery of wales. the following letter will serve more fully to exhibit the enthusiasm he experienced in contemplating nature in her wild and simplest forms. to samuel purkis, esq. matlock, august , . my dear friend, had i been alone, and perfectly independent as to my plans, i should probably have written to you long ago. i should have begged you to hasten your departure, so that we might have rejoiced together in wales, under the influence of that moon which is now full in all its glory; for derbyshire, taken as a whole, has not pleased me. a few beautiful valleys, placed at the distance of many miles from each other, do not compensate for the almost uniform wildness and brown barrenness of the hills and plains; and in the watering places, there is little amongst the _living beings_ to awaken deep moral feelings, or to call the nobler powers of the mind, which act in consequence of sympathy, into existence. i have longed for the mountain scenery, and for the free inhabitants of north wales; and even the majestic valleys of the wye and the derwent have been to me but typical of something more perfect in beauty and grandeur. whenever it shall seem fitting to you, i shall be prepared for our long contemplated journey, and do not delay your departure;--_before_ the st would be more agreeable to me than _after_ that period; and then we shall be able to view the horns of the next moon, where they are most beautiful. i have enquired much concerning dove-dale, since i have been here, and, from the most accurate accounts, i am inclined to believe that it is inferior, in point of sublime scenery, to _chee tor_, near bakewell, and in beauty, to the valley of the _great tor_, in which i am now writing. on the whole, i think your best plan will be to meet me at matlock, which you must see, and then, in our route to buxton, we can visit the valley of the wye, and the most noble _chee tor_. concerning the excursion of dove-dale, i am undecided, and it shall depend upon you to determine with regard to it. as one great object in our excursions is to view nature and man in their most simple forms, and to gain a temporary life of new impressions, i submit to you whether it will not be best to steer clear of _towns_, _cities_, and _civilized society_, in which, for the most part, we can see what we have only seen before. if we visit sir joseph banks, it certainly should be only _en passant_: and to see that most excellent personage, and to be obliged to quit him immediately, will be at least painful; for the respectful feelings he produces in the mind are always modified by affection. i have no room to give you the quantity of information that i have gained concerning the places and people of wales; this shall serve for our derbyshire chat. i thank you much for your last kind letter, which gave me high pleasure. you possess the true spirit of composition, which embodies facts in words. i am, &c. h. davy. i am informed by mr. purkis, that in the latter end of this summer, he made a pedestrian tour with davy, through north and south wales, and he has transmitted to me the following account of this excursion.--"we visited every place possessing any remains of antiquity, any curious productions of nature or art, and every spot distinguished by romantic and picturesque scenery. our friend's diversified talents, with his knowledge of geology, and natural history in general, rendered him a most delightful companion in a tour of this description. every mountain we beheld, and every river we crossed, afforded a fruitful theme for his scientific remarks. the form and position of the mountain, with the several _strata_ of which it was composed, always procured for me information as to its character and classification; and every bridge we crossed invariably occasioned a temporary halt, with some appropriate observations on the productions of the river, and on the diversion of angling. "in one of our morning excursions in north wales, we ascended the summit of _arran benllyn_, a celebrated mountain, inferior only to snowdon and cader idris, a few miles from the lake of bala. here we were fortunate in beholding a scene of extraordinary sublimity, seldom witnessed in this climate. from the top of this mountain we looked down, about mid-day, on a deep valley eight or ten miles in length, and as many in breadth, the whole of which, for a considerable height from the surface of the ground, was filled with beautiful clouds, while the atmosphere around the summit on which we stood was perfectly clear, and the sky above us of a deep blue colour. the clouds in the valley were in irregular, gentle undulations, dense, compact, and continuous, of that kind which is denominated by meteorologists _cirro-cumulus_, and by the vulgar, _woolpack_ clouds, such as are often seen in the higher regions on a fine summer's day. the sun shone with great brilliancy, and illumined their various forms with silver, grey and blue tints of exquisite beauty. as there was scarcely a breath of air stirring below the mountain, this aggregation of clouds, probably occasioned by some electrical agency, remained fixed and stationary, as if identified with the valley. the higher parts of most of the surrounding hills were enveloped in mist, above which the tops of _snowdon_ and _cader idris_ towered distinctly visible, and appeared like small islands rising out of the sea. this scene altogether was one of inexpressible magnificence and grandeur, filling the mind with awe and rapture. we seemed to feel ourselves like beings of a higher order in a celestial region, looking down on the lower world with conscious superiority. "after sitting and ruminating on this sublime spectacle for two or three hours, we left the summit of the mountain with reluctance, and, slowly descending, rested at intervals, and often cast a longing, lingering look behind. "on reaching our comfortable inn at bala, while waiting for dinner, davy walked about the room, and, as if by inspiration, broke out in a beautiful impassioned apostrophe on the striking scene we had so recently witnessed. it was in a kind of unmeasured blank verse, highly animated and descriptive, at once poetical and philosophical. at the conclusion of this eloquent effusion, i endeavoured to recollect and commit it to writing, but i could not succeed, and davy was too modest to assist my memory. "in a tour through north wales, where the few small inns have seldom any spare rooms, different parties are often obliged to sit in the same apartment, and to eat at the same table. hence we were occasionally introduced to characters of various descriptions, some of whom gratified us by their agreeable qualities, while others disgusted us by their ignorance and impertinence. on one occasion, after a heavy shower of rain in the middle of august, we were drying our clothes by the fire in the little inn at _tan y bwlch_, when the landlord requested us to admit a gentleman, who was very wet. a young man, of pleasing appearance and manner, was then introduced, and after some common-place observations, we sat down to dinner. the stranger was evidently a man of education and acquirements, and after the cloth had been removed, he began to discourse very fluently on scientific subjects. he talked of oxygen and hydrogen, of hornblende, and the _grawacké_ of werner, and geologists, in the most familiar tone of self-complacency. "davy's youth, simplicity of manner, and cautious concealment of superior knowledge, not exciting constraint, our companion was naturally induced to deliver his opinions with the utmost freedom and confidence on all subjects. we commenced on poetry and painting; the sublime and beautiful; then proceeded to mineralogy, astronomy, &c. and occasionally digressed on topics of mirth and humour, so that the evening was passed with general satisfaction. "when davy had retired to rest, and i was left alone with our companion, i enquired how he liked my friend, and whether he considered him a proficient in science, and versed in chemistry and geology? he answered coolly, that 'he appeared to be rather a clever young man, with some general scientific knowledge.' he then asked his name, and when i announced 'davy, of the royal institution,' the stranger seemed thunderstruck, and exclaimed, 'good god! was that really davy? how have i exposed my ignorance and presumption!' it is scarcely necessary to add, that at the breakfast table the next morning, he talked on subjects of science with less volubility than on the preceding evening." after davy's return from this expedition, he wrote the following letter. to davies giddy, esq. royal institution, oct. , . my dear sir, it is long since i have had the pleasure of hearing from you. you probably received a hasty letter that i wrote to you in the beginning of the summer. since that period, i have been idling away much of my time in derbyshire and north wales. till very lately, i had hopes of being able to spend a few weeks of the autumn in cornwall, but i now find that it will not suit with my occupations. not having it in my power to see you, you may believe that i am most anxious to hear from you. we hear, at this time, in london of comparatively few scientific novelties. the wonders of revolutionized paris occupy many of our scientific men; and the summer and autumn are not the working seasons in great cities. the rich and fashionable part of the community think it their duty to kill time in the country, and even philosophers are more or less influenced by the spirit of the times. in the last volume of the manchester memoirs, _i.e._ the fifth, are some papers of mr. dalton on the constitution of the atmosphere; on the expansive powers of steam; and on the dilatation of elastic fluids by heat. as far as i can understand his subjects, the author appears to me to have executed them in a very masterly way. i wish very much to have your judgment upon his opinions, some of which are new and very singular. have you yet seen the theory of my colleague, dr. young, on the undulations of an ethereal medium as the cause of light? it is not likely to be a popular hypothesis, after what has been said by newton concerning it. he would be very much flattered if you could offer any observations upon it, whether for or against it. the paper is in the last volume of the transactions. i believe i mentioned to you in a former letter that _terra japonica_, or _extractum catechu_, contained a very large proportion of the tanning principle. my friend mr. purkis, an excellent practical tanner, has lately tried some experiments upon it in the large way. it answers very well, and i am now wearing a pair of shoes, the leather of one of which was tanned with oak-bark, and that of the other with _terra japonica_; and they appear to be equally good. we are in great hopes that the east india company will consent to the importation of this article. one pound of it goes at least as far as nine pounds of oak-bark; and it could certainly be rendered in england for less than four-pence the pound: oak-bark is nearly one penny per pound. the _zoonic acid_, which m. berthollet supposed to be a peculiar acid, has been lately shown by m. thénard to be only acetous acid, holding a peculiar animal matter in solution. gregory watt is just returned from the continent, where he has passed the last fifteen months. he has been much delighted with his excursion, but his health is at present bad. i trust, however, that english roast-beef and english customs will speedily restore it. we are publishing, at the royal institution, a journal of science, which contains chiefly abridged accounts of what is going on in different parts of europe, with some original papers; and in hopes that its diffusion may become more general, we have fixed its price at one shilling. as soon as i have an opportunity, i will send you the last numbers of it. i am beginning to think of my course of lectures for the winter. in addition to the common course of the institution, i have to deliver a few lectures on vegetable substances, and on the connection of chemistry with vegetable physiology, before the board of agriculture. i have begun some experiments on the powers of soils to absorb moisture, as connected with their fertility. i have, for this purpose, made a small collection of those of the _calcareous_ and _secondary_ countries, and i wish very much for some specimens from the _granitic_ and _schistose_ hills of cornwall. if you could, without much trouble, cause to be procured from your estates different pieces of uncultivated soil, of about a pound weight each, i should feel much obliged to you. they should be accompanied by specimens of the stone or strata on which they lie. i am, dear sir, with affection and respect, yours, h. davy. of the journals alluded to in the above letter, it would seem that davy and dr. young were the joint editors. the former appears both as a reviewer and an original writer, and in each capacity we recognise the peculiarities of his genius: in the one case, by the quickness with which he detects error; and in the other, by the avidity with which he apprehends truth. it will not be uninteresting to take a short review of his original communications, especially as the work has become extremely scarce; indeed, as it was published in numbers, it is very probable that only a few copies have escaped the common fate of periodicals. his first paper is entitled, "an account of a new eudiometer," and has for its principal object the recommendation of the solution of the green muriate, or sulphate of iron, impregnated with _nitrous_ gas; the knowledge of the properties of which, in absorbing oxygen gas, arose out of those experiments to which an allusion has been already made.[ ] [ ] see page . this test is prepared by transmitting a current of nitrous gas through a saturated solution of the salt of iron. as the absorption of the gas proceeds, the solution acquires the colour of a deep olive brown; and when the impregnation is completed, it appears opaque and almost black. the process is apparently owing to a simple elective attraction; in no case is the gas decomposed; and under the exhausted receiver it resumes its elastic form, leaving the fluid with which it was combined, unaltered in its properties. the test, therefore, can only be regarded as a convenient modification of that of priestley, in which the nitrous gas was presented to the atmospheric air to be examined, without the intervention of any third body. the only apparatus required for the application of the test, as suggested by davy, is a small graduated tube, having its capacity divided into one hundred parts, and a vessel for containing the fluid. the tube, after being filled with the air to be examined, is introduced into the solution, and shaken in contact with it; when the air will be rapidly diminished in volume, and the whole of its oxygen, in a few minutes, condensed into nitrous acid. by means of this test, davy informs us that he examined the atmosphere in different places, without being able to ascertain any notable difference in the proportions of its component parts. twenty-eight years have elapsed since the publication of this paper; and yet, amidst the rapid progress of discovery, eudiometry has not been able even to modify the results it has given us; but the reader will be pleased to remember, that by these tests it is only professed to show the relative proportions of oxygen in air; the salubrity of an atmosphere depends upon many other causes, especially its condition with regard to moisture, which, in a variety of ways, exerts an influence upon the structures of the body. in this journal we also find several original communications from davy on galvanic phenomena, which will be noticed on a future occasion. there is likewise a paper of considerable interest, entitled, "an account of a method of copying paintings upon glass, and of making profiles, by the agency of light upon nitrate of silver, invented by t. wedgwood, esq.: with observations by h. davy." in the first place, he gives an account of the experiments of mr. wedgwood, and then, with his usual sagacity, extends our knowledge of the subject by his own researches. chemists had been long acquainted with the fact, that white paper, or white leather, moistened with a solution of the _nitrate of silver_, although it does not undergo any change when kept in a dark place, will speedily change colour on being exposed to daylight; and that, after passing through different shades of grey and brown, it will at length become nearly black. these alterations in colour take place more speedily in proportion as the light is more intense. in the direct beams of the sun, two or three minutes are sufficient,--in the shade, several hours are required, to produce the full effect; and light transmitted through differently coloured glass, acts upon it with different degrees of intensity. it is found, for instance, that red rays, or the common sunbeams passed through red glass, have very little action upon it; yellow and green are more efficacious; but blue and violet produce the most decided and powerful effects. davy observes that these facts were analogous to those which were long ago observed by scheele, and confirmed by senebier. to mr. wedgwood, however, belongs the merit of having first applied them for the ingenious purpose of copying engravings, &c. his first attempt was to copy the images formed by the _camera obscura_; but they were found to be too faint to produce, in any moderate time, the necessary changes upon the _nitrate of silver_. with paintings on glass he was more successful; for the copying of which, the solution should be applied on leather, which is more readily acted upon than paper. when a surface thus prepared is placed behind a painting on glass, exposed to the solar light, the rays transmitted through the differently coloured surfaces produce distinct tints of brown or black, sensibly differing in intensity, according to the shades of the picture; and where the light is unaltered, the colour of the _nitrate_ becomes deepest. besides this application of the method of copying, there are many others. it may be rendered subservient for making delineations of all such objects as are possessed of a texture partly opaque, and partly transparent; such, for instance, as the woody fibres of leaves, and the wings of insects; for which purpose, it is only necessary to cause the direct solar light to pass through them, and to receive the shadows upon prepared leather. to davy we are indebted for an extremely beautiful application of this principle,--that of copying small objects produced by means of the solar microscope. for the success, however, of this experiment, it is necessary that the prepared leather should be placed at a small distance only from the lens. the copy of a painting, or the profile of an object, thus obtained, must of course be preserved in an obscure place; for all the attempts that have been made to prevent the uncoloured parts of the copy from being acted upon by light, have hitherto been unsuccessful. they have been covered with a thin coating of fine varnish; and they have been submitted to frequent washings; yet, even after this latter operation, it would seem that a sufficient quantity of the active matter will still adhere to the white parts of the surface, and cause them to become dark on exposure to the rays of the sun. from this circumstance, davy thinks it probable that a portion of the metallic oxide abandons its acid, to enter into union with the animal or vegetable substance, so as to form with it an insoluble compound. it will be remembered that davy had made some early experiments on the collision of flint and steel _in vacuo_:[ ] we find in the royal institution journal a farther investigation of the subject; when he admits that, although sparks are not produced under these circumstances, yet that a faint light becomes visible. in many instances, he refers the phenomenon to electricity excited by friction, more especially in the instances of glass, quartz, sugar, &c. which give out light when rubbed. in other cases, he considers it probable that a species of phosphorescence may be occasioned by the heat; and he thinks that there may occasionally take place an actual ignition of abraded particles, in consequence of their imperfect conducting power: a supposition which he thinks receives strong support from an experiment of mr. wedgwood, who found that a piece of window-glass, when brought into contact with a revolving wheel of grit, became red hot at its point of friction, and gave off luminous particles that were capable of inflaming gunpowder and hydrogen gas. [ ] see page . we shall also find in this volume an account of some observations which he made upon the motions of small pieces of _acetate of potash_, during their solution, upon the surface of water. after the interesting and extraordinary observations of mr. brown, every phenomenon of this kind is calculated to excite attention. davy states that the fragments were agitated by very singular motions during the time of their solution, sometimes revolving for a second or two, and then moving rapidly backwards and forwards in various directions. he considers the phenomenon as evidently connected with the rapid process of solution, since the motions became weaker as the point of saturation approached. the thinnest film of oil, or of ether, wholly destroyed the effect. those pieces which were most irregular in their forms underwent, by far, the most rapid motions; from which, he thinks, it would appear, that the phenomenon was in some measure owing to changes in the centre of gravity of the particles during their solution. the projectile motions, however, would seem to depend upon the continual descent of a current of the saline solution from the agitated particle, in consequence of which, the surrounding water would press upon different parts of it with different degrees of force. besides which, an increase of temperature, which was found to accompany the solution of the salt, might in a degree modify the effect. his first communication to the royal society was entitled "an account of some galvanic combinations, formed by an arrangement of single metallic plates and fluids, analogous to the galvanic apparatus of m. volta." it was read on the th of june , and will be examined in a future part of these memoirs. the certificate, recommending him as a candidate for the honour of a seat in the royal society, was read for the first time on the st of april ; and having been duly suspended in the meeting-room, during ten sittings of the society, according to the statute, he was put to the ballot, and elected on the th of november in the same year. as every circumstance connected with the progress of davy will be hereafter viewed with considerable interest, i shall here introduce the form of the certificate, and record the names of those fellows who sanctioned it by their signatures. "humphry davy, esq. professor of chemistry in the royal institution of great britain, a gentleman of very considerable scientific knowledge, and author of a paper in the philosophical transactions, being desirous of becoming a fellow of the royal society, we the undersigned do from our personal knowledge recommend him as deserving that honour, and as likely to prove an useful and valuable member. (signed) morton, r. j. sullivan, kinnaird, charles hatchett, thomas young, webb seymour, w. g. maton, thomas rackett, james edward smith, w. g. jordan, john walker, richard chenevix, alexander crichton, henry c. englefield, charles wilkins, giffin wilson, gilbert blane, edward forster." on the th of july, in the same year, he was elected an honorary member of the dublin society, having been proposed from the chair by the vice-president, general vallancey. it has been stated that, shortly after davy's arrival at the institution, the managers, being anxious to encourage all investigations of a practical tendency, directed him to deliver a series of lectures on the art of tanning. with this view, he entered into a scientific examination of the subject, in which he was encouraged by sir joseph banks, the liberal patron and promoter of all useful knowledge, who supplied him with various materials for experiment. the subject had recently attracted considerable attention, both at home and abroad, but much still remained to be effected; and davy succeeded in adding many important facts to the general store. in the royal institution journal already noticed, we find several communications from him, under the titles of "observations on different methods of obtaining gallic acid;"--"on the processes of tanning," &c. all the new facts however, discovered in the course of his experiments, were embodied in a long and elaborate memoir, which was read before the royal society on the th of february , and published in the philosophical transactions for that year. it was entitled "an account of some experiments and observations on the constituent parts of certain astringent vegetables, and on their operation in tanning. by humphry davy, professor of chemistry in the royal institution. communicated by the right honourable sir joseph banks, p. r. s." although seguin and proust had already examined many of the properties of that vegetable principle to which the name of _tannin_ had been given, yet its affinities had been but little examined; and the manner in which its action upon animal matters may be modified by combination with other substances, had been still less considered. his principal design in this enquiry was to elucidate the practical part of the art of tanning skins, so as to form leather; but in pursuing this object, he was necessarily led into chemical investigations connected with the analysis of the various bodies containing the tanning principle, and the peculiar properties and value of each. the vegetable principles that had been regarded as more usually present in astringent infusions, are _tannin_, _gallic acid_, and _extractive matter_. in attempting to ascertain the relative proportions of _tannin_ contained in different infusions, davy was led, after various trials, to prefer the generally received method of precipitating by means of _gelatine_ procured from isinglass. in using this test, however, he discovered that several precautions were necessary;--that the solution should be quite fresh,--that it should be as much saturated as may be compatible with its fluidity,--and that the precipitate obtained should be reduced to a uniform degree of dryness. it is evident that if the quantity of gelatine in the solution, employed as the precipitant, be known, it will only be necessary to ascertain the weight of the precipitate produced by it, in order to learn the absolute proportion of tannin present in any specimen. he next directed his attention to the discovery of some method by which the _gallic acid_ might be separated from _extractive matter_, in cases where they exist in combination, but the enquiry was not successful; for, as he observes, it is difficult to render the _extractive_ insoluble, so as to separate it, without at the same time decomposing the gallic acid. it is true that æther will dissolve the latter, without exerting much action upon the former; but then, he adds, whenever the gallic acid is in large quantities, this method will fail, "in consequence of that _affinity_ which is connected with mass." here then he adopts that celebrated theory of berthollet,[ ] which he afterwards so vigorously and successfully attacked.[ ] [ ] récherches sur les lois de l'affinité.--mém. de l'institut national, tome iii. p. . [ ] the masterly manner in which he combated the successive arguments of berthollet upon this question is admirable. in the first place, he attacked the theory upon general principles, and then exposed the fallacy of the several experiments adduced in its support. "were the proposition correct, that _in all cases of decomposition in which two bodies act upon a third, that third is divided between them in proportion to their relative affinities, and their quantities of matter_, it is quite evident that there could be scarcely any definite proportions: a salt crystallizing in a strong alkaline solution would be strongly alkaline; in a weak one, less alkaline; and in an acid solution it would be acid." with regard to glasses and alloys, adduced by m. berthollet as compounds of indefinite proportions, davy answers--"it is not easy to prove, in such cases, that the elements are chemically combined, for the points of fusion of alkali, glass, and certain metallic oxides, are so near to each other, that transparent mixtures of them may be formed." the experiment upon which m. berthollet laid great stress, viz. that a large quantity of potash will separate a small quantity of sulphuric acid from sulphate of baryta, davy invalidates in a most complete manner. he says--"this experiment was made in contact with the atmosphere, in which carbonic acid is always present; and carbonate of potash and sulphate of baryta mutually decompose each other." as general tests of the respective quantities of these two principles (gallic acid and extractive matter), he employed the solutions of the salts of alumina and those of the peroxidated salts of iron. the former of these precipitates _extractive_, without materially acting upon _gallic acid_, which is thrown down by the latter: the greatest care, however, must be taken not to add the iron in excess, as in that case the black precipitate formed will be redissolved, and an olive-coloured and clear fluid be only obtained. he details the results of a number of experiments made upon galls, and ascertains the relative proportions of their several elements; and he proves that tannin may exist in such a state of combination in different substances as to elude the test of gelatine; in which case, to detect its presence, it is necessary to have recourse to the action of the diluted acids. sir joseph banks had concluded, from the sensible properties of _catechu_,[ ] or _terra japonica_, that it was rich in tannin: davy confirmed this opinion by experiment. the leather tanned by it appeared to possess the same qualities as when tanned in the usual manner; and although this substance contains a small portion of extractive matter, yet the increase of weight of the skin was rather less than when solutions of galls were used. [ ] catechu is an extract obtained from the wood of a species of the _mimosa_ that grows in india, by boiling and subsequent evaporation. it is of two kinds; one from bengal, the other from bombay. the former contains rather less, the latter rather more, than half its weight of tannin. the remainder in both cases is a peculiar extractive matter mixed with mucilage.--p. in examining different barks, he was not able to procure from them any free gallic acid, but their infusions gave, on evaporation, tannin and extractive. the greater number of his experiments were made on the barks of the oak, the leicester willow, the spanish chestnut, the elm, and the common willow. the largest quantity of tannin he found to be contained in the interior, or white cortical layers; and the largest quantity of extractive matter in the exterior layers; the epidermis, or rough outward bark, did not contain either the one or the other. from his general observations he is inclined to suppose that, in all the astringent vegetables, the tannin is of the same species, and that all the differences attributed to it depend upon its state of combination with other principles. in applying the results of his experiments to the theory of tanning, he considers the process as simply depending upon the union of the tannin with the matter of the skin, in such a manner as to form with it an insoluble compound. gallic acid, he feels assured, does not produce any notable effects in the process; but he thinks that the quality of the leather depends, in some degree, upon the quantity of extractive matter it may imbibe. skin, combined with extractive matter only, would be increased in weight, become coloured, and be extremely flexible, but it would not be insoluble in water; and were it combined with tannin alone, it would be heavier and less supple than when both these principles enter into the compound. he examines with great acuteness and precision some of the more popular opinions entertained by tanners, and brings his science to bear very satisfactorily upon several of their processes. the grand secret, on which the profit of the trade mainly depends, is to give the hides the greatest increase of weight in the least possible time. to effect this, various schemes have been proposed, many of which, from the ignorance of the operators, instead of promoting, have defeated the object. different _menstrua_ have been suggested for expediting the process, and amongst them lime-water and the solutions of pearl-ash; but, as he has clearly shown, these two substances form compounds with tannin which are not decomposable by gelatine; whence it follows that their effects must be pernicious; and there is very little reason to suppose that any bodies will be found which, at the same time that they increase the solubility of tannin in water, will not likewise diminish its attraction for skin. his experiments having proved that the saturated infusions of astringent barks contain much less extractive matter, in proportion to their tannin, than those which are weaker, it follows, that by quickly tanning the skin, we render the leather less durable. these observations show that there is some foundation for the vulgar opinion of workmen, concerning what is technically called the _feeding_ of leather in the slow method of tanning. such is an outline of this interesting paper, in which the author has displayed the talent so characteristic of his mind--that of bringing science and art into useful alliance with each other. it forms, at this day, the guide of the tanner; and those who previously carried on the process by a routine of operations, of which they knew not the reasons, are now capable of modifying it, without the risk of spoiling the result. many of those expedients which have been brought forward as novelties in later years, may be found in this paper; or, at least, have arisen out of the principles disclosed during his investigations. it has been stated that, shortly after davy's successful _début_ as a lecturer, his manners underwent a change, and that, to the regret of his friends, he lost much of his native simplicity. on the th of february , he had dined with sir harry englefield at his house at blackheath; and eighteen years afterwards, the worthy baronet alluded to his interesting demeanour upon that occasion, in terms sufficiently expressive of his feelings--"it was the last flash of expiring nature." it was natural that his best friends, on perceiving this change of manner, should entertain some apprehensions as to the deeper qualities of his heart. mr. purkis has placed in my hands the following letter addressed to him by mr. coleridge; it will interest the reader by the force and truth with which its talented writer characterises the perils which beset the elevated path of the young philosopher at the commencement of his career. to samuel purkis, esq. nether stowey, feb. , . my dear purkis, i received your parcel last night, by post, from gunville, whither (crossly enough) i am going with our friend poole to-morrow morning. i do from my very heart thank you for your prompt and friendly exertion, and for your truly interesting letter. i shall write to wedgwood by this post; he is still at cote, near bristol; but i shall take the _bang_ back with me to gunville, as wedgwood will assuredly be there in the course of ten days. jos. wedgwood is named the sheriff of the county. when i have heard from wedgwood, or when he has tried this _nepenthe_, i will write to you. i have been here nearly a fortnight; and in better health than usual. tranquillity, warm rooms, and a dear old friend, are specifics for my complaints. poole is indeed a very, very good man. i like even his incorrigibility in small faults and deficiencies: it looks like a wise determination of nature to let well alone; and is a consequence, a necessary one perhaps, of his immutability in his important good qualities. his journal, with his own comments, has proved not only entertaining but highly instructive to me. i rejoice in davy's progress. there are three suns recorded in scripture:--joshua's, that stood still; hezekiah's, that went backward; and david's, that went forth and hastened on his course, like a bridegroom from his chamber. may our friend's prove the latter! it is a melancholy thing to see a man, like the sun in the close of the lapland summer, meridional in his horizon; or like wheat in a rainy season, that shoots up well in the stalk, but does not _kern_. as i have hoped, and do hope, more proudly of davy than of any other man; and as he has been endeared to me more than any other man, by the being a thing of hope to me (more, far more than myself to my own self in my most genial moments,)--so of course my disappointment would be proportionally severe. it were falsehood, if i said that i think his present situation most calculated, of all others, to foster either his genius, or the clearness and incorruptness of his opinions and moral feelings. i see two serpents at the cradle of his genius, dissipation with a perpetual increase of acquaintances, and the constant presence of inferiors and devotees, with that too great facility of attaining admiration, which degrades ambition into vanity--but the hercules will strangle both the reptile monsters. i have thought it possible to exert talents with perseverance, and to attain true greatness wholly pure, even from the impulses of ambition; but on this subject davy and i always differed. when you used the word "gigantic," you meant, no doubt, to give me a specimen of the irony i must expect from my philo-lockian critics. i trust, that i shall steer clear of almost all offence. my book is not, strictly speaking, metaphysical, but historical. it perhaps will merit the title of a history of metaphysics in england from lord bacon to mr. hume, inclusive. i confine myself to facts in every part of the work, excepting that which treats of mr. hume:--_him_ i have assuredly besprinkled copiously from the fountains of bitterness and contempt. as to this, and the other works which you have mentioned, "have patience, lord! and i will pay thee all!" mr. t. wedgwood goes to italy in the first days of may. whether i accompany him is uncertain. he is apprehensive that my health may incapacitate me. if i do not go with him, (and i shall be certain, one way or the other, in a few weeks,) i shall go by myself, in the first week of april, if possible. poole's kindest remembrances i send you on my own hazard; for he is busy below, and i must fold up my letter. whether i remain in england or am abroad, i will occasionally write you; and am ever, my dear purkis, with affectionate esteem, your's sincerely, s. t. coleridge. remember me kindly to mrs. purkis and your children. t. wedgwood's disease is not painful: it is a complete _tædium vitæ_; nothing pleases long, and novelty itself begins to cease to act like novelty. life and all its forms move, in his diseased moments, like shadows before him, cold, colourless, and unsubstantial. from the tone of the following letter, it may be presumed also, that mr. poole, to whom it is addressed, had expressed some anxiety upon the dangers to which his flattering station exposed him. to thomas poole, esq. london, may , . my dear poole, have you no thoughts of coming to london? i have always recollected the short periods that you have spent in town, with a kind of mixed feeling of pleasure and regret. in the bustling activity occasioned in cities by the action and re-action of diversified talents, occupations, and passions, our existence is, as it were, broken into fragments, and with you i have always wished for unbroken intercourse and continuous feeling. * * * * * be not alarmed, my dear friend, as to the effect of worldly society on my mind. the age of danger has passed away. there are in the intellectual being of all men, permanent elements, certain habits and passions that cannot change. i am a lover of nature, with an ungratified imagination. i shall continue to search for untasted charms,--for hidden beauties. my _real_, my _waking_ existence is amongst the objects of scientific research: common amusements and enjoyments are necessary to me only as dreams, to interrupt the flow of thoughts too nearly analogous to enlighten and to vivify. coleridge has left london for keswick; during his stay in town, i saw him seldomer than usual; when i did see him, it was generally in the midst of large companies, where he is the image of power and activity. his eloquence is unimpaired; perhaps it is softer and stronger. his will is probably less than ever commensurate with his ability. brilliant images of greatness float upon his mind: like the images of the morning clouds upon the waters, their forms are changed by the motion of the waves, they are agitated by every breeze, and modified by every sunbeam. he talked in the course of one hour, of beginning three works, and he recited the poem of christobel unfinished, and as i had before heard it. what talent does he not waste in forming visions, sublime, but unconnected with the real world! i have looked to his efforts, as to the efforts of a creating being; but as yet, he has not even laid the foundation for the new world of intellectual forms. when my agricultural lectures are finished, i propose to visit paris, and perhaps geneva. how i regret that circumstances had not enabled us to make the same tour at the same time! i think, at all events, i shall see you before the autumn, on your own lands, amidst your own images and creations. your affectionate friend, humphry davy. to the same. royal institution. my dear poole, often, very often, in the midst of the tumults of the multitude in this great city, has my spirit turned in quietness and solitude towards you. i hope soon to see you in somersetshire, where we may worship nature, and the spirit that dwells in nature, in your green fields and under your tranquil sky. my communications with you and coleridge and southey, and other ornaments of the great existing being, have excited feelings which cheer me in the apathy of london, and which make me love human nature. * * * * * your account of the young man who murdered his wife, i read with deep interest. it is from such narratives of the conduct of common persons, that the laws of simple human nature must be deduced. beings acted on by few objects, awakening in them few but deep passions, are the beings which metaphysicians and moralists ought to study; not those who exist in general life, having their energies and feelings so attached to multiplied and indefinite things--so mixed up and connected with myriads of circumstances, as to be imperceptible, unless by a microscopic moral eye. i am, &c. &c. h. davy. from the former letter, we learn that davy, at this period, proposed delivering some lectures on the chemistry of agriculture. from the memorandums of my late friend mr. arthur young, the celebrated secretary to the board of agriculture, i have succeeded, through the kindness of his daughter, in procuring the following extracts; the only source from which i have been able to obtain any correct information upon this point in his scientific life.--"may th, . _mem._ two lectures by mr. davy have taken place, and been very well attended; they intend retaining him by a salary of a hundred pounds a year,--a very good plan." amongst the pamphlets at bradfield hall is a small quarto of fourteen pages, entitled, "outlines of a course of lectures on the chemistry of agriculture, to be delivered before the board of agriculture, ." it was evidently only printed for private circulation amongst the members. at the same time, he printed a small pamphlet, containing an explanation of the terms used in chemistry, for the instruction of those amongst his audience who had not particularly directed their attention to the science. the first lecture was delivered on tuesday, may the th, at twelve at noon, and five others on the succeeding tuesdays and fridays. in an address to the board of agriculture by sir john sinclair, delivered in april , in reviewing the various objects to which the attention of the board had been directed, he thus alludes to the subject:--"in the year , when my lord carrington was in the chair, the board resolved to direct the attention of a celebrated lecturer, mr. davy, to agricultural subjects; and in the following year, during the presidency of lord sheffield, he first delivered to the members of this institution, a course of lectures on the chemistry of agriculture. the plan has succeeded to the extent which might have been expected from the abilities of the gentleman engaged to carry it into effect. the lectures have hitherto been exclusively addressed to the members of the board; but to such a degree of perfection have they arrived, that it is well worthy of consideration, whether they ought not to be given to a larger audience. if such an idea met with the approbation of the board, a hall might be procured for that purpose, or a special course of lectures read in this room exclusively for strangers." davy would appear to have been very early impressed with the importance of chemistry, in its various applications to agriculture. allusions are constantly made to it in his letters; and at the conclusion of his "researches," he glances at this department of the chemistry of vegetation, and observes that, "although it is immediately connected with the art upon which we depend for subsistence, it has been but little investigated." in his introductory lecture of , he speaks more forcibly upon the subject. "agriculture, to which we owe our means of subsistence, is an art intimately connected with chemical science; for although the common soil of the earth will produce vegetable food, yet it can only be made to produce it in the greatest quantity, and of the best quality, by methods of cultivation dependent upon scientific principles. "the knowledge of the composition of soils, of the food of vegetables, of the modes in which their products must be treated, so as to become fit for the nourishment of animals, is essential to the cultivator of land; and his exertions are profitable and useful to society, in proportion as he is more of a chemical professor. since indeed the truth has been understood, and since the importance of agriculture has been generally felt, the character of the agriculturist has become more dignified, and more refined;--no longer a mere machine of labour, he has learned to think, and to reason. he is aware of his usefulness to his fellow-men, and he is become, at once, the friend of nature, and the friend of society." his appointment, as chemical professor to the board of agriculture, was accompanied with the obligation of reading lectures before its members; which he continued to deliver every successive season for ten years, modifying and extending their views, from time to time, in such a manner as the progress of chemical discovery might render necessary. these discourses were collated, and published in the year , at the request of the president and members of the board, and they form the only systematic work we, at present, possess on the subject. its views, however, are too generally interesting to be briefly dismissed; i shall therefore enter more fully into their merits in a more advanced part of these memoirs. his connexion with the board necessarily brought him in contact with the practical agriculturists and capitalists of the day, with many of whom he formed friendships which lasted through life. with mr. coke of holkham he became well acquainted, and generally formed one of the party at his annual sheep-shearing.[ ] he was also a frequent visitor at woburn, and received from the duke the means by which he was enabled to submit to the test of practice various theories which his science had suggested. [ ] in the th volume of the "annals of agriculture," an account is given of the holkham sheep-shearing for , and in the list of the company is the name of "mr. professor davy."--at the meeting of , he was also present, and is mentioned as the great chemist, whose discoveries will immortalize his name. mr. coke, in the course of his speech after dinner, alluding to the question of long and short dung, said, "it is the opinion of a friend of mine, who sits near me, professor davy, and upon whose judgment, on account of his extensive chemical as well as other scientific knowledge, i place the highest reliance, that the manure carried immediately on the field, without being disturbed, will have a greater effect in exciting rapid vegetation, and in encouraging the growth of the turnip plant, than when applied in the ordinary manner; for, under such circumstances, it will not only be more moist and alkaline, but it will be protected from a loss of substance, amounting very nearly to one-third of its original bulk." davy afterwards, in company with the duke of bedford, lord william russell, lord thanet, sir joseph banks, and other agriculturists, inspected several farms.--in , his health was drunk at the woburn sheep-shearing by the duke of bedford; and in the following festival it was proposed by lord hardwicke. in the print of the "woburn sheep-shearing," published by garrard, in , no. represents davy; he is standing, in a listening attitude, behind mr. coke, who is conversing with sir joseph banks, sir john sinclair, and mr. arthur young. in a letter to mr. gilbert, dated october , he says: "i have just quitted the coast of sussex, where i have spent the last three weeks with lord sheffield, the worthy biographer of gibbon." in fact, there was not a nobleman, distinguished for intellectual superiority, who did not feel a pride in receiving him as a guest; and he passed his vacations in the society of those exalted persons who, in possessing rank, fortune, and talents, felt that they only held such gifts from providence, in trust for the welfare of their fellow-countrymen. we can scarcely picture to ourselves a being upon whom fortune ever showered more favours than upon davy, during this golden period of his career. independent in an honourable competence, the product of his genius and industry; resident in the centre of all scientific information and intelligence; every avenue of knowledge, and every mode of observation open to his unwearied intellect, he must have experienced a satisfaction which few philosophers have ever before felt,--the power of pursuing experimental research to any extent, and of commanding the immediate possession of all the means it might require, without the least regard either to cost or labour. what a contrast does this picture afford to that which has been too faithfully represented as the more usual fate of the philosopher and man of letters, and which exhibits little more than the unavailing struggles of genius against penury! instead of a life consumed in fruitless expectation of patronage and reward, we behold davy, in the full bloom of reputation, courted by all whom rank, talent, or station, had rendered conspicuous. his life flowed on like a pure stream, under a sky of perpetual sunshine,--not a gust ruffled its surface, not a cloud obscured its brightness. in the morning, he was the sage interpreter of nature's laws; in the evening, he sparkled in the galaxy of fashion; and not the least extraordinary point in the character of this great man, was the facility with which he could cast aside the cares of study, and enter into the trifling amusements of society.--"_ne otium quidem otiosum_," was the exclamation of cicero; and it will generally apply to the leisure of men actively engaged in the pursuits of science; but davy, in closing the door of his laboratory, opened the temple of pleasure. when not otherwise engaged, his custom was to play at billiards, frequent the theatre, or read the last new novel. in ordinary cases, the genius of evening dissipation is an arrant penelope; but davy, on returning to his morning labours, never found that the thread had been unspun during the interruption. the following anecdote is well calculated to illustrate that versatility of talent of which i have frequently spoken, as well as the power he possessed of abstracting himself, without detriment, from the most elaborate investigations. a friend of the late mr. tobin called upon him at the institution, and found him deeply engaged in the laboratory; their conversation turned upon "the honey moon," which was to be brought out on the following evening.[ ] no sooner had davy heard that, although pressing applications had been made to several of the poets of the day, a prologue had not yet been written, than he instantly quitted the laboratory, and in two hours produced that which was recited on the occasion by mr. bartley, and printed in the first edition of the comedy. i insert it in this place. [ ] "the honey moon" was produced at drury lane, on thursday, the th of january, . no uniformity in life is found:-- in ev'ry scene varieties abound; and inconsistency still marks the plan of that immortal noble being,--man. as changeful as the april's morning skies, his feeling and his sentiments arise; and nature to his wond'rous frame has given the mingled elements of earth and heaven. in diff'rent climes and ages, still we find the same events for different ends design'd: and the same passion diff'rent minds can move to thoughts of sadness or to acts of love. hence genius draws his novel copious store; and hence the new creations we adore: and hence the scenic art's undying skill submits our feeling to its potent will; from common accidents and common themes awakens rapture and poetic dreams; and, in the trodden path of life, pursues some object clothed in fancy's loveliest hues-- to strengthen nature, or to chasten art, to mend the manners or exalt the heart. so thought the man whom you must judge to-night; and as he thought, he boldly dared to write. not new the subject of his first-born rhyme; but one adorn'd by bards of elder time;-- bards with the grandest sentiments inspired-- bards that in rapture he has still admired; and tried to imitate, with ardour warm, and catch the spirit of their pow'rful charm. with loftiest zeal and anxious hope, he sought to bring to modern times their strength of thought; and, in their glowing colours, to display the follies and the virtues of the day. whether his talents have his wish belied, your judgment and your candour must decide. he, though your loftiest plaudits you should raise-- he cannot thank you for the meed of praise. rapture he cannot feel, nor fear, nor shame; connected with his love of earthly fame, he is no more.--yet may his memory live in all the bloom that early worth can give! should you applaud, 'twould check the flowing tear of those to whom his name and hopes are dear. but should you an unfinish'd structure find, as in its first and rudest forms design'd, as yet not perfect from the glowing mind, then with a gentle voice your censure spread, and spare the living--spare the sacred dead! davy would appear to have frequently amused himself with writing sonnets, and inclosing them in letters to his several friends: the following letter will also show that he was ambitious of being considered a poet. to samuel purkis, esq. my dear purkis, i inclose the little poem,[ ] on which your praise has stamped a higher value, i fear, than it deserves. if i thought that people in general would think as favourably of my poetical productions, i would write more verses, and would write them with more care; but i fear you are partial: i am very glad, however, that you like the little song; at some future period i will send you another. with kind remembrances, unalterably your sincere friend, h. davy. [ ] the subject was "_julia's eyes_." on examining the laboratory notes made at this period, many of which, however, are nearly illegible from blots of ink and stains of acid, it would appear that his researches into the composition of mineral bodies were most extensive, and that he obtained many new results, of which he does not seem to have availed himself in any of his subsequent papers. to borrow a metaphor from his favourite amusement, he treated such results as small fry, which he returned to their native element to grow bigger, or to be again caught by some less aspiring brother of the angle. had davy, at this period of his life, been anxious to obtain wealth,[ ] such was his chemical reputation, and such the value attached to his judgment, that, by lending his assistance to manufacturers and projectors, he might easily have realized it; but his aspirations were of a nobler kind--scientific glory was the grand object for which his heart panted: by stopping to collect the golden apples, he might have lost the race. [ ] i am assured by one of his earliest friends, that, at this period, he did not appear even to have an idea of the value of property. any thing not immediately necessary to him he gave away, and never retained a book after he had read it. chapter v. sir thomas bernard allots davy a piece of ground for agricultural experiments.--history of the origin of the royal institution.--its early labours.--davy's letters to mr. gilbert and to mr. poole.--death of mr. gregory watt.--davy's passion for fishing, with anecdotes.--he makes a tour in ireland: his letters on the subject.--his paper on the analysis of the wavellite.--his memoirs on a new method of analysing minerals which contain a fixed alkali.--reflections on the discovery of galvanic electricity. very shortly after davy had arrived in london, he formed an intimate friendship with mr. (afterwards sir thomas) bernard; and no sooner had he directed his attention to the subject of philosophical agriculture, than the worthy baronet allotted him a considerable piece of ground near his villa at roehampton, where, under his sole direction, numerous experiments were tried, many of which proved highly successful, and afterwards served for the illustration of various subjects in his work on agricultural chemistry. although devoted as davy was to the pursuits of science, he entered warmly into all political plans for improving the condition of the people, and advancing the progress of civilization. "no one," says his friend mr. poole, "was less a sectarian, if i may use the word, in religion, politics, or in science. he regarded with benevolence the sincere convictions of any class on the subject of belief, however they might differ from his own. in politics, he was the ardent friend of rational liberty. he gloried in the institutions of his country, and was anxious to see them maintained in their purity by timely and temperate reform." indeed, in carefully analysing his mind, and tracing its developement, it appears that benevolence was one of its leading elements; the form in which it displayed its energies varying with the varying conditions of intelligence. in boyish life, his imagination, acting upon his zeal for the welfare of his species, delighted, as we have seen, in the ideas of encountering dragons, and quelling the might of giants; but as fancy paled with the light of advancing years, and the judgment, presented distincter appearances, the philanthropic antipathy which had been directed to those chimeras of the nursery, was transferred to the two great oppressions of society, and in superstition he saw the dragons--in despotism, the giants that spread mischief and misery through the world. some of his early manuscripts are still in existence; and i shall here introduce a passage from one which has been lately transmitted to me by a gentleman resident in penzance. the most trifling record becomes interesting, when we can trace in it the germ of a particular opinion, or the first symptom of a quality which may afterwards have distinguished its possessor. "science is as yet in her infancy; but in her infancy she has done much for man. the discoveries hitherto so beneficial to mankind have been generally effected by the energies of individual minds:--what hopes may we not entertain of the rapid progress of the happiness of man when illumination shall become general--when the united powers of a number of scientific men shall be employed in discovery! every thing seems to announce the rapid advance of this period of improvement. the time is approaching when despotism and superstition, those enormous chains that have so long enfettered mankind, shall be annihilated,--when liberated man shall display the mental energies for which he was created. at that period, nations shall know that it is their interest to cultivate science, and that the benevolent philosophy is never separated from the happiness of mankind." in his published writings, we discover evidences of the same tendency; he suffers no opportunity to escape which can enable him to enforce his principle, and he extracts from the most common as well as from the least probable sources, comparisons and analogies for its illustration. the ingenuity with which this is accomplished often surprises and delights us; the effect upon the reader is frequently not unlike that occasioned by the flashes of wit, to which it surely must be closely allied, if wit be correctly defined by johnson "a combination of dissimilar images, or the discovery of occult resemblances in things apparently unlike." is not this opinion strikingly illustrated by the happy turn given to his observations "upon the process of obtaining nitrous oxide from nitre,"--when he says, "thus, if the hopes which these experiments induce us to indulge do not prove fallacious, a substance which has heretofore been almost exclusively appropriated to the destruction of mankind, may become, in the hands of philosophy, the means of producing health and pleasure!" mr. poole, who watched the whole of his progress from obscurity to distinction, and enjoyed his friendship for nearly thirty years, says, "to be useful to science and mankind was, to use his favourite expression, the pursuit in which he gloried. he was enthusiastically attached to science, and to men of science; and his heart yearned to promote their interests." that davy, with a mind so constituted, should have formed a strong and ardent attachment to sir thomas bernard, and that this friendship should have been reciprocally cultivated, cannot be a matter of surprise. i am happy in this opportunity of paying a tribute of respect to the memory of this most excellent person, with whom i had the pleasure of being well acquainted. his life was one continued scheme of active benevolence; and he merits a particular notice in these memoirs, as being one of the principal founders and patrons of the royal institution. actuated by that noble and rational ambition which makes private pursuits subservient to public good, he directed all the energies of his mind, the influence of his station, and the resources of his wealth, towards promoting societies and schemes for encouraging the virtues and industry, and for ameliorating the condition, of the lower classes. in the beginning of november , in conjunction with the late bishop of durham, mr. wilberforce, and mr. elliot, he established the society for bettering the condition of the poor. as one of the primary objects of the original promoters of this society was the formation of an institution which might teach the application of science to the advancement of the arts of life, and to the increase of domestic comforts, a select committee was appointed from its body, in january , for the purpose of conferring with count rumford on the means of carrying such a scheme into practical effect. this committee consisted of the earl of winchelsea, mr. wilberforce, mr. sullivan, the bishop of durham, sir thomas bernard, and some other members of the society; and in a few weeks they completed the arrangements, circulated printed proposals, and collected the subscriptions, which gave birth to the royal institution of great britain, the future cradle of experimental science, and the destined scene of davy's glory. in addition to the general objects of promoting the arts and manufactures, and of advancing the taste and science of the country, its more immediate purpose was the improvement of the means of industry and domestic comfort among the poor. that this benevolent design was constantly kept in sight may be shown by the several resolutions passed at the different meetings of the managers, especially at that held in march ; when it was resolved to appoint _fourteen_ different committees, for the purpose of scientific investigation and improvement; amongst which were the following:-- "for the investigation into the processes of making bread, and into the methods of improving it. "for enquiring into the art of preparing cheap and nutritious soups for feeding the poor. "for improving the construction of cottages, and cottage fire-places, and for improving kitchen fire-places, and kitchen utensils. "for ascertaining, by experiment, the effects of the various processes of cookery upon the food of cattle. "for improving the construction of lime-kilns, and the composition of mortar and cements," &c. &c. so that the foundation and original arrangements of the royal institution were not only calculated to extend the boundaries of science, but to increase its applications, and to promote and improve those arts of life on which the subsistence of all, and the comfort and enjoyment of the great majority of mankind absolutely depend. at this early period of its history, the royal institution presented a scene of the most animated bustle and exhilarating activity. persons most distinguished in the various departments of science and art were to be seen zealously and liberally co-operating for the promotion and diffusion of public happiness, under the cheering beams of popular favour and exalted patronage. it was like 'a busy ant-hill in a calm sunshine.' i shall only add, that sir thomas bernard was the original promoter of the "school for the indigent blind;" of an institution for the protection and instruction of "climbing boys;" of a society for the relief of "poor neighbours in distress;" of the "cancer institution;" and of the "london fever hospital." the philanthropic baronet was, moreover, the founder of the "british institution," for promoting the fine arts in the united kingdom; and he was also the originator of the "alfred club." the vast range and practical utility of these exertions were duly appreciated by his contemporaries, who were ever ready to promote any scheme which had received the sanction of his patronage. it is an anecdote worthy of being preserved, that the late sir robert peel called upon him one morning, and after a general conversation on the different philanthropic objects they had in view, said on leaving the room, he had to request that sir thomas would dispose of something for him, in any manner he thought most serviceable, and laid on the table an enclosure. after he had left the house, sir thomas was greatly surprised, on opening it, to find a bank-note of a thousand pounds. the active zeal of sir t. bernard, like every other circumstance which exceeds the ordinary standard of our conduct, or becomes prominent from the rarity of its occurrence, called forth the wit as well as the admiration of his contemporaries. one of those modern travellers who delight in astonishing their auditors by incredible tales and marvellous anecdotes, happening to be in company with a noble lord as much distinguished for the playfulness of his wit as for the profundity of his learning, told the following improbable story: that, in a sequestered part of italy, when pressed by hunger and fatigue, he sought refreshment and repose in a wild dwelling in the mountains, and was agreeably surprised at being offered a pie; but, horror of horrors! on examining its contents he found--a human finger!--"nothing more probable, sir," interrupted his lordship; "and i well know the person to whom that finger belonged--to sir thomas bernard, sir, for he had a finger in every pie." the following letters will be read in this place with interest. to davies giddy, esq. my dear sir, i am now on my way to christchurch, in company with mr. bernard, who was the founder, and has been the great supporter, of the society for bettering the condition of the poor. in a conversation that has just passed between us, i mentioned the state of improvement of the downs between helston and marazion, in consequence of grants of small portions of land to miners and other tenants for cultivation, many of which have, i believe, been made by lord dunstanville. mr. bernard expressed a desire to know what the effect of this plan had been on the condition of the persons thus raised into "property-men." he is accumulating facts as to the manner in which the poor have been most effectually benefited, and to assist his labour would be to assist a good and most important cause; perhaps, you will have the goodness to give me a statement on this subject, which of course shall be used as you may think proper. you may likewise have similar facts nearer home, on your own estates. i am convinced that the effects of enabling the common labourer to acquire property must be striking, and must often have been an object of your contemplation. in making any statement of these facts, you will probably think it right to mention some particular cases, with dates, names, and accounts of the quantities of lands, the nature of the improvements, &c. in the reports of the "society for bettering the condition of the poor," there is one made on this minute plan of lord winchelsea's grants of land to cottagers, which conveys very full and useful information. i trust to your kindness, and believe me your obliged, h. davy. the following letter was written by davy after his return from an excursion to that beautiful district, the north-west of the county of somerset. to thomas poole, esq. october, . my dear poole, i returned to town a little while ago, not sorry to see the great city of activity and life; not sorry to see it, though i had just spent two months in enjoying a scenery beautiful and, to me, new; in witnessing much hospitality and unadulterated manners, and in gaining much useful information. mr. bernard is writing a history of the poor. i have lived much with him at roehampton since my return, and he has read to me part of his work, which is popularly eloquent, very intelligent, and full of striking and important truths; but pray say nothing of this, for it is likely that it will appear without his name: the facts will be strong, and perhaps to some people offensive. i have received a letter from coleridge within the last three weeks: he writes from malta, in good spirits, and, as usual, from the depth of his being. god bless him!--he was intended for a great man; i hope and trust he will, at some period, appear as such. i am working very hard at this moment, and i hope soon to send you some of the fruits of my labours. i am likewise devising some plans at our institute, for the improvement of "this generation of vipers;" but, although i am so vain as to announce them, i will not be so tedious as to detail them. in your answer, which i hope i shall soon receive, pray give me an account of the situation of "poole's marsh," with regard to the _parrot_,[ ] for i have mentioned the soil in a paper to the board of agriculture, which is now in the press. i am, my dear poole, your truly affectionate friend, h. davy. [ ] he alludes to a rich piece of land near the river parrot; a specimen of the soil of which mr. poole had sent him for analysis. in this year, davy was deprived of one of his earliest and most attached friends, after a lingering illness, during which his symptoms, by the alternations which characterise consumption, had inspired his friends with hope, only to chill them with despondency;--gregory watt terminated his earthly career.[ ] [ ] gregory watt was one of those philosophers to whose memory justice has not awarded its due. he was a meteor, whose light no sooner flashed upon us than it expired. his paper upon the gradual refrigeration of basalt, alone entitled him to a distinguished rank amongst experimentalists. it was read before the royal society in may; and he expired in the following october. on the first impression which this melancholy event produced upon his feelings, davy wrote a letter to his friend clayfield, from which the following is an extract. "i scarcely dare to write upon the subject--i would fain do what hamlet does, when, in awe and horror at the ghost of his father, he attempts to call up the ludicrous feeling, but being unable to do so, he merely employs the words which are connected with it.--i would be gay, or i would write gaily, in alluding to the loss we have both sustained, but i feel that it is impossible. poor watt!--he ought not to have died. i could not persuade myself that he would die; and until the very moment when i was assured of his fate, i would not believe he was in any danger. "his letters to me, only three or four months ago, were full of spirit, and spoke not of any infirmity of body, but of an increased strength of mind. why is this in the order of nature, that there is such a difference in the duration and destruction of her works? if the mere stone decays, it is to produce a soil which is capable of nourishing the moss and the lichen; when the moss and the lichen die and decompose, they produce a mould which becomes the bed of life to grass, and to a more exalted species of vegetables. vegetables are the food of animals,--the less perfect animals of the more perfect; but in man, the faculties and intellect are perfected,--he rises, exists for a little while in disease and misery, and then would seem to disappear, without an end, and without producing any effect. "we are deceived, my dear clayfield, if we suppose that the human being who has formed himself for action, but who has been unable to act, is lost in the mass of being: there is some arrangement of things which we can never comprehend, but in which his faculties will be applied. "the caterpillar, in being converted into an inert scaly mass, does not appear to be fitting itself for an inhabitant of air, and can have no consciousness of the brilliancy of its future being. we are masters of the earth, but perhaps we are the slaves of some great and unknown beings. the fly that we crush with our finger, or feed with our viands, has no knowledge of man, and no consciousness of his superiority. we suppose that we are acquainted with matter, and with all its elements, and yet we cannot even guess at the cause of electricity, or explain the laws of the formation of the stones which fall from meteors. there may be beings,--thinking beings, near us, surrounding us, which we do not perceive, which we can never imagine. we know very little; but, in my opinion, we know enough to hope for the immortality, the _individual immortality of the better part of man_. "i have been led into all this speculation, which you may well think wild, in reflecting upon the fate of gregory! my feeling has given erring wings to my mind. he was a noble fellow, and would have been a great man.--oh! there was no reason for his dying--he ought not to have died. "blessings wait on you, my good fellow! pray remember me to tobin, and, if you read this letter to him, protest, the moment he begins to argue against the immortality of man! "i came yesterday from the borders of dorsetshire, where i have been since monday, seduced to travel by a friend. i was within sixty miles of you, and saw divers fair trout-streams: let the fish beware of me,--i shall be at them on monday." i have included this latter sentence in my extract, as being highly characteristic of the writer. his passion for angling betrayed itself upon all occasions; and the sport was alike his relief in toil, and his solace in sorrow. to his conversation, as well as to his letters, we may aptly apply the words of the augustan poet:-- "desinit in piscem----formosa superne." whenever i had the honour of dining at his table, the conversation, however it might have commenced, invariably ended on fishing; and when a brother of the angle happened to be present, you had the pleasure of hearing all his encounters with the finny tribe--how he had lured them by his treachery, and vanquished them by his perseverance. he would occasionally strike into a most eloquent and impassioned strain upon some subject which warmed his fancy; such, for example, as the beauties of mountain scenery; but before you could fully enjoy the prospect which his imagination had pictured, down he carried you into some sparkling stream, or rapid current, to flounder for the next half hour with a hooked salmon! i remember witnessing, upon one of these occasions, a very amusing scene, which may be related as illustrative of some peculiarities of his temper. i believe all those who have accompanied davy in his fishing excursions, will allow that no sportsman was ever more ambitious to appear skilful and lucky. nothing irritated him so much as to find that his companions had caught more fish than himself; and if, during conversation, a brother fisherman surpassed him in the relation of his success, he betrayed similar impatience. there happened to be present, on the occasion to which i allude, a skilful angler, and an enterprising chemist. the latter commenced on some subject connected with his favourite science; but davy, who, generally speaking, disliked to make it a subject of conversation, suddenly turned to the angler, and related what he considered a very surprising instance of his success: his sporting friend, however, mortified him by the relation of a still more marvellous anecdote; upon which davy as quickly returned to the chemist, who, in turn, again sent him back to the angler:--and thus did he appear to endure the unhappy fate of the _flying fish_, who no sooner escapes from an enemy in the regions of air, than he is pursued by one equally rapacious in the waters.--but to return to the thread of our history. in referring to the records of the institution, it appears that in january , davy greatly enriched the cabinets of the institution by a present of minerals. the following are the minutes of the committee upon this occasion: "january , .--mr. hatchett reported that, in pursuance of the request of the managers, he had inspected the minerals presented to the royal institution by mr. davy, and that the aggregate value (including the duplicate specimens) appears to him to exceed one hundred guineas." "january .--the managers took into consideration mr. hatchett's report at the last meeting, and resolved that mr. davy is entitled to the thanks of the managers for having added so valuable a present to the collection of minerals belonging to the institution." on the th of february, it was resolved--"that mr. davy be appointed director of the laboratory, at a salary of one hundred pounds a-year; by which his annual income from the institution was raised to four hundred pounds. at this period he delivered a series of lectures on geology, or on the chemical history of the earth; to which we find an allusion in the following letter." to thomas poole, esq. february, . my dear poole, i am very much obliged to you for your last kind letter, and i thank you most sincerely for the exertion of your friendship at bath. i thank you with very warm feelings. i hope you will soon come to town; that you will stay a long time; and that we shall be very much together. i paid your subscription to arthur young for the smithfield club. pray, at all times, command me to do any thing i can for you in london:--you cannot teaze me; and though i am a very idle fellow, yet i can always work if the stimulus be the desire of serving such a friend as yourself. i am giving my course of lectures on geology to very crowded audiences. i take a great interest in the subject; and i hope the information given will be useful. there has been no news lately from coleridge; the last accounts state that he was well in the autumn, and in sicily. on that poetic ground, we may hope and trust that his genius will call forth some new creations, and that he may bring back to us some garlands of never-dying verse. i have written to urge him strongly to give a course of lectures on poetry at the royal institution, where his feeling would strongly impress, and his eloquence greatly delight. i am, my dear poole, most affectionately yours, h. davy. on the th of may, in this year, mr. hatchett reported to the managers of the institution--"that mr. davy proposed making a journey into wales and ireland this summer, having in view to collect specimens for enriching the mineralogical cabinets;" in consequence of which it was resolved--"that the sum of one hundred pounds be entrusted to mr. davy to purchase minerals, and to defray the incidental charges; and that the boy of the laboratory, william reeve,[ ] be ordered to attend him on his tour, and that the steward be directed to defray his expenses." [ ] there are some circumstances of interest connected with the history of this young man. he possessed much chemical talent; but during his residence in ireland he was converted to the catholic religion, and is at this time a catholic priest in some part of the continent. from the following letters, it would appear that, having accomplished his purpose of visiting ireland, he made a rapid journey into cornwall for the sake of seeing his mother and sisters. to davies giddy, esq. okehampton, september . my dear sir, i am accompanying my friend mr. bernard in a tour through the west of england, and i hope we shall reach penzance in two or three days. mr. bernard wishes much for the honour of your acquaintance, and i trust you will permit me to have the pleasure of making you known to him. much kindness and long knowledge of him, may have made me partial to that gentleman, and may perhaps influence me when i say, that there is not a more patriotic, good, and public-spirited man in great britain. i came from ireland by the western road, about a fortnight ago. my expectations were fully satisfied with the appearances of the "giant's causeway." the arrangements of rocks of the northern cape of ireland appear to me to present facts equally irreconcilable upon either the plutonic or neptunian theory; and i am convinced that general fanciful theories will lose ground in proportion as minute observations are multiplied. the irish are a noble race, degraded by slavery, and bearing the insignia of persecution, extreme savageness, or the lowest servility; yet they are ingenious and active, and seem to me to possess all the elements of power and usefulness; but amongst the lower orders there is a most unfortunate equality, destructive of all great and efficient exertion; and amongst the higher classes the greatest degree of activity is awakened only by the desire of imitating the english, and that not so much in their virtues and talents, as in their luxuries and follies. i hear from all quarters of the good effects of your late exertions in parliament. may your efforts tend to establish the reign of good sense and pure philosophy, in a place where they have been too often found to yield to empty sounds! yours, &c. h. davy. to thomas poole, esq. london, oct. , . my dear poole, i made a very rapid journey to cornwall with mr. bernard, merely for the sake of showing him the country, and for the purpose of spending a week with my mother and sisters. we made an effort to come to you at nether stowey, but the people at bridgewater would not take us round, through stowey, to taunton, without four horses; and at all events we could only have spent two or three hours with you; and it is difficult to say whether the pleasure of meeting, or the regret at parting so soon, would have been the greatest. i long very much for the intercourse of a week with you. i have very much to say about ireland. it is an island which might be made a new and a great country. it now boasts a fertile soil, an ingenious and robust peasantry, and a rich aristocracy; but the bane of the nation is the equality of poverty amongst the lower orders. all are slaves without the probability of becoming free; they are in the state of equality which the _sansculottes_ wished for in france; and until emulation and riches, and the love of clothes and neat houses, are introduced amongst them, there will be no permanent improvement. changes in political institutions can at first do little towards serving them. it must be by altering their habits, by diffusing manufactories, by destroying _middle-men_, by dividing farms,[ ] and by promoting industry by making the pay proportioned to the work. but i ought not to attempt to say any thing on the subject when my limits are so narrow; i hope soon to converse with you about it. i found much to interest me in geology in ireland, and i have brought away a great deal of information, and many specimens. i shall now be in london till christmas, with the exception of next week, which i am obliged to pass in bedfordshire. i am, my dear poole, most affectionately your's, h. davy. [ ] he means that the _middle-men_ being discontinued, their large allotments should be divided into farms of convenient extent, the occupiers of which should rent immediately from the owners of the soil. after the giant's causeway, the scenery which called forth davy's greatest admiration in ireland was that of fair-head. to an enthusiastic lover of the wild and sublime features of nature, an object of greater interest could scarcely be presented than a vast promontory, the summit of which rises five hundred feet above the sea, and at whose base lies a waste of rude and gigantic columns, swept by the hand of time from the mountain to which they formerly belonged. the following fragment, written by davy at the time, has been placed in my hands by mr. greenough. "----but chiefly thee, fair-head! unrivall'd in thy form and majesty! for on thy loftiest summit i have walk'd in the bright sunshine, while beneath thee roll'd the clouds in purest splendour, hiding now the ocean and his islands--parting now as if reluctantly: whilst full in view the blue tide wildly roll'd, skirted with foam, and bounded by the green and smiling land, the dim pale mountains, and the purple sky. majestic cliff! thou birth of unknown time, long had the billows beat thee, long the waves rush'd o'er thy hollow'd rocks, ere life adorn'd thy broken surface, ere the yellow moss had tinted thee, or the mild dews of heaven clothed thee with verdure, or the eagles made thy cave their aëry: so in after time long shalt thou rest unalter'd mid the wreck of all the mightiness of human works; for not the lightning nor the whirlwind's force, nor all the waves of ocean, shall prevail against thy giant strength--and thou shalt stand till the almighty voice which bade thee rise shall bid thee fall." amongst davy's letters to mr. gilbert, in the years and , i find several upon the subject of the elastic force of steam, at different temperatures, with reference to mr. trevitheck's improvements in the steam-engine; in one of which he says, "i shall be extremely happy to hear of the results of your enquiries, and i hope you will not confine them to your friends, but make them public. whenever speculative leads to practical discovery, it ought to be well remembered, and generally known: one of the most common arguments against the philosophical exercise of the understanding is, _cui bono?_ it is an absurd argument, and every fact against it ought to be carefully registered. trevitheck's engine will not be forgotten; but it ought to be known and remembered that your reasonings and mathematical enquiries led to the discovery." on the th of february , was read before the royal society, and published in the transactions of that year, a paper entitled, "an account of some analytical experiments on a mineral production from devonshire, consisting principally of alumina and water; by humphry davy, &c." this mineral was first discovered by dr. wavel, in small veins and cavities, in a tender argillaceous slate, near barnstaple in devonshire. at first it was considered as a species of _zeolite_, until mr. hatchett concluded, from its geological position, that it did not belong to that family of minerals. dr. babington subsequently suspected from its physical characters, and from some of its habitudes with acids, that it was a mineral not before described, and accordingly placed a quantity of it in davy's hands for analysis; who, on finding in its composition little more than clay and water, proposed to change the name of _wavellite_ for that of _hydrargyllite_, as better expressive of its chemical nature. he however, at the same time, alludes to traces of an acid which he was unable to identify. in a letter to mr. nicholson, dated killarney, june , , and which was afterwards published in his journal, davy refers to this fact in the following manner:-- dear sir, i shall feel much obliged to you to mention that i have found the acid which exists in minute quantities in wavellite to be the _fluoric acid_, in such a peculiar state of combination as not to be rendered sensible by sulphuric acid. i am, &c. h. davy. my late friend the reverend william gregor, having found the wavellite at stenna gwynn, in cornwall, submitted it to experiment, and the result certainly established the conclusion of the presence of fluoric acid, though not rendered apparent by the usual tests. the facts were transmitted to the royal society, and published in a paper entitled, "on a mineral substance, formerly supposed to be zeolite; by the reverend william gregor." the subsequent experiments of berzelius, however, cleared away the obscurity in which the subject was still involved. he showed that this mineral not only contained in its composition a small portion of the _neutral fluate of alumina_, but he demonstrated the presence of a _sub-phosphate_ of that earth, to no inconsiderable an amount. much has been said of the error committed on this occasion by davy, in overlooking thirty-three per cent. of phosphoric acid; but the _phosphate of alumina_ is a body that might very easily have escaped notice at a period when mineral analysis was in a far less advanced state than it is at present. on the th of may , davy communicated to the royal society a paper "on the method of analyzing stones containing a fixed alkali, by means of the boracic acid." this method was founded upon two important facts: first, on the considerable attraction of boracic acid for the different simple earths at the heat of ignition; and, secondly, on the facility with which the compounds so formed are decomposed by the mineral acids. the processes are extremely simple, and the method must be considered as having advanced the art of mineral analysis. for this and his preceding papers, the president and council of the royal society adjudged to him their copley medal. in , mr. poole, having consulted davy on the subject of a mine occurring near nether stowy, received from him the following letter, which is interesting from the political opinions it displays. to thomas poole, esq. my dear poole, what you have written concerning the indifference of men with regard to the interest of the species in future ages, is perfectly just and philosophical; but the greatest misfortune is, that men do not attend even to their own interest, and to the interest of their own age in public matters. they think in moments, instead of thinking, as they ought to do, in years; and they are guided by expediency rather than by reason. the true political maxim is, that the good of the whole community is the good of every individual; but how few statesmen have ever been guided by this principle! in almost all governments, the plan has been to sacrifice one part of the community to other parts:--sometimes, the people to the aristocracy; at other times, the aristocracy to the people;--sometimes, the colonies to the mother-country; and at other times, the mother-country to the colonies. a generous enlightened policy has never existed in europe since the days of alfred; and what has been called "the balance of power"--the support of civilization,--has been produced only by jealousy, envy, bitterness, contest, and eternal war, either carried on by pens or cannon, destroying men morally and physically! but if i proceed in vague political declamation, i shall have no room left for the main object of my letter--your mine. i wish it had been in my power to write decidedly on the subject; but your county is a peculiar one: such indications would be highly favourable in cornwall; but in a _shell-limestone_ of late formation, there have as yet been no instances of great copper mines. i hope, however, that your mine will produce a rich store of _facts_. miners from alston moor, or from derbyshire, would understand your country better than cornish miners, for the cornish shifts are wholly different from yours. it would be well for you to have some workmen at least from the north, as they are well acquainted with _shell-limestone_. the ecton copper mine in staffordshire is in this rock: it would be right for you to get a plan and a history of that mine, which might possibly assist your views. had i been rich, i would adventure; but i am just going to embark with all the little money i have been able to save for a scientific expedition to norway, lapland, and sweden. in all climes, i shall be your warm and sincere friend, h. davy. on the death of dr. edward whitaker gray, secretary of the royal society, davy was elected into that office, at an extraordinary meeting of the society, on the nd of january ; and at the same time he was elected a member of the council. we are now advancing to that brilliant period in the history of our philosopher, at which he effected those grand discoveries in science, which will transmit his name to posterity, associated with those of newton, bacon, locke, and the great master-spirits of every age and country:--i speak of his developement of the laws of voltaic electricity. i approach the subject with that diffidence which the contemplation of mighty achievements must ever produce in the mind of the historian, when he compares the extent and magnitude of his subject with the limited and feeble powers which are to describe them. as the advantages afforded by the history of any great discovery consist as much in exhibiting, step by step, the intellectual operations by which it was accomplished, as in detailing its nature and applications, or in examining its relations with previously established truths; so shall i be unable to preserve a chronological succession in the examination of those several memoirs which he presented to the royal society, without breaking asunder that fine intellectual thread, by which his mind was conducted through the intricate paths of nature from known to unknown phenomena. for this reason, although i announced, according to the date of its publication, the subject of his first paper on electricity, i deferred entering upon its examination, until i might be able to bring into one uninterrupted view the whole enquiry, in all its branches and bearings. it is impossible to enter upon the subject of galvanism, or voltaic electricity, without recurring to the circumstance which first betrayed the existence of such an energy in nature, and to the sanguine expectations which the discovery so naturally excited. on witnessing the powerful contraction of a muscular fibre by the mere contact of certain metals, it was rational to conclude, that the nature and operation of the mysterious power of vital irritability might, at length, be discovered by a new train of scientific research. it is a curious fact, that an experiment so full of promise to the physiologist should have hitherto failed in affording him any assistance in his investigations; while the chemist, to whom it did not, at first, appear to offer any one single point of interest, has derived from it a new and highly important instrument of research, which has already, under the guidance of davy, multiplied discoveries with such rapidity, and to such an extent, that it is not even possible to anticipate the limits of its power. we have here, then, another striking instance of a great effect produced by means apparently insignificant. who could have imagined it possible, that the spasmodic action occasioned in the limb of a frog, by the accidental contact of a pair of scissors, should have become the means of changing the whole theory of chemistry--of discovering substances, whose very existence was never suspected--of explaining the anomalous associations of mineral bodies in the veins of the earth--of protecting surfaces of metal from the corrosive action of the elements--of elucidating the theories of volcanoes and earthquakes--and, may we not add? of leading the way to a knowledge of the laws of terrestrial magnetism! such an unexpected extension of an apparently useless fact should dispose us to entertain a kinder regard for the labours of one another, and teach us to judge with diffidence of the abstract results of science. a discovery which may appear incapable of useful application to-day, may be our glory to-morrow,--it may even change the face of empires, and wield the destiny of nations. the conic sections of apollonius pergæus remained useless for two thousand years: who could have supposed that, after the lapse of twenty centuries, they would have formed the basis of astronomy?--a science giving to navigation safety, guiding the pilot through unknown seas, and tracing for him in the heavens an unerring path to his native shores. some apology may be necessary for this digression; but, i confess, the subject has always appeared to me to be capable of much interesting illustration, and i heartily concur in the opinion expressed by the accomplished author of "lettres à sophie"--"_l'histoire des grands effets par les petites causes ferait un livre bien curieux._" chapter vi. the history of galvanism divided into six grand epochs.--davy extends the experiment of nicholson and carlisle.--his pile of one metal and two fluids.--dr. wollaston advocates the doctrine of oxidation being the primary cause of voltaic phenomena.--davy's modification of that theory.--his bakerian lecture of .--he discovers the sources of the acid and alkaline matter eliminated from water by voltaic action.--on the nature of electrical decomposition and transfer.--on the relations between the electrical energies of bodies, and their chemical affinities.--general developement of the electro-chemical laws.--illustrations, applications, and conclusions. the history of galvanism may be divided into six grand epochs; each being distinguished by the discovery of facts variously interesting from their novelty, and from the extent and importance of their applications. it cannot be expected that i should enter into a minute history of the science; such a labour would require a distinct work for its accomplishment. i shall therefore follow the plan of the architect, who, in presenting a finished drawing of a part, sketches a faint outline of the whole edifice to which it belongs, in order that its fair proportions may appear in proper breadth and relief. the first epoch may be considered as arising out of the fundamental fact discovered by galvani in --that the contact of two different metals with the nerve of a recently killed frog will excite distinct muscular contractions. the second epoch may be dated from the discovery of what might be termed _organic_ galvanism, or the production of its influence, without the presence of animal organs, by the peculiar action of metals upon water, as first observed by dr. ash. the third epoch will long be celebrated on account of the discovery of the accumulation of the galvanic power, by the invention of the pile of volta, made known in the first year of the present century, and which so distinctly exhibited the analogy between galvanism and electricity, that the energy thus excited is now generally spoken of as "_voltaic electricity_." the fourth epoch may be considered as founded upon the knowledge of the general connexion between the excitement of voltaic electricity and chemical changes. the fifth epoch is exclusively indebted for its origin to davy--the establishment of the general law, that galvanism decomposes all compound bodies, and that the decomposition takes place in a certain determinate manner. the sixth and last epoch is founded upon the discovery of the relations subsisting between electricity and magnetism; giving origin to a new branch of science, which has been distinguished by the name of "electro-magnetism." galvani,[ ] from the moment of his first discovery, always referred the effects he produced to an electrical origin; but he considered that the metals employed merely acted as conductors, which effected a communication between the different parts of an animal, naturally, or by some process of nature, in opposite states of electricity, and that the muscular contractions took place during the restoration of the equilibrium. [ ] the simple fact relating to the action of metals on the animal organs was certainly not first observed by galvani, but by sulzer, who has described the sensation of taste produced by the contact of lead and silver with the tongue, in his _théorie des plaisirs_, in . until the researches of dr. ash,[ ] ritter, fabroni, and creve, had been made known, the galvanic influence was generally considered as existing only in the living organs of animals, from which it might be elicited by certain processes. [ ] m. humboldt (_ueber die gereize faser_, l. , ,) quotes part of a letter from dr. ash, in which it is said that, "if two finely polished plates of homogeneous zinc be moistened and laid together, little effect follows; but if zinc and silver be tried in the same way, the whole surface of the silver will be covered with oxidated zinc. lead and quicksilver act as powerfully upon each other, and so do iron and copper." m. humboldt says, that, in repeating this experiment, he saw air bubbles ascend, which he supposes to have been hydrogen gas from the decomposition of water. in the bakerian lecture[ ] read before the royal society in , davy, in giving a retrospective view of the progress of electro-chemical science, very justly remarks, that the true origin of all that has been done in this department of philosophy was the accidental discovery of nicholson and carlisle, of the decomposition of water by the pile of volta, on the th of april, in the year ; which was immediately followed by that of the decomposition of certain metallic solutions, and by the observation of the separation of alkali on the negative plates of the apparatus. mr. cruickshank, in pursuing these experiments, obtained many new and important results, such as the _decomposition of the muriates of magnesia_, _soda_, and _ammonia_; and also observed the fact, that alkaline matter always appeared at the negative, and acid matter at the positive pole.[ ] [ ] as this lecture will be frequently mentioned in the progress of these memoirs, in connexion with most important discoveries, it may be interesting to the reader to learn something of its foundation and design. i have therefore collected the necessary information from the minutes of the royal society. mr. baker is well known in the history of science, as an accurate observer with the microscope, and as the author of several works on the subject. by his will, dated july , he bequeathed the sum of one hundred pounds, the interest of which he directed "to be applied for an oration or discourse, to be read or spoken yearly by some one of the fellows of the royal society, on such parts of natural history, or experimental philosophy, at such time, and in such manner, as the president and council of the said society shall please to order and appoint; on condition, nevertheless, that if any one year shall pass after the payment of the said hundred pounds, without such oration or discourse having been read or spoken at some meeting of the said royal society, the said hundred pounds shall then become forfeited, and shall be repaid by the said society to his executors," &c. baker died in november , and in the following year a fellow was nominated to read the lecture. it is a whimsical circumstance, that the first lecturer should have been peter woulfe, the last of the alchemists. the names of the successive lecturers were as follow:--dr. ingenhouz, mr. cavallo, mr. vince, dr. wollaston, dr. young, sir h. davy, mr. brande, captain kater, captain edward sabine, and mr. herschel. [ ] nicholson's journal, vol. iv. p. . no sooner had davy become acquainted with the curious experiments of nicholson and carlisle, than, as we learn from his letter to mr. gilbert,[ ] bearing the date of july , he proceeded to repeat them. indeed, it was the early habit of his mind not only to originate enquiries, but without delay to examine the novel results of other philosophers; and in numerous instances it would seem, that he only required to confirm their accuracy before he succeeded in rendering the application of them subservient to farther discovery. this was certainly the case with respect to the subject before us: he was a discoverer as soon as he became an enquirer. it is admirable to observe with what a quick perception he discovered the various bearings of a new fact, and with what ingenuity he appropriated it for the explanation of previously obscure phenomena. in referring to the "additional observations" appended to his "chemical researches," we shall find that the moment he became acquainted with the experiments of dr. ash, he proceeded to enquire how far the fact, previously noticed by himself, of the conversion of nitrous _gas_ into nitrous _oxide_, by exposure to wetted zinc, might depend upon galvanic action. [ ] see page . in the month of september , he published his first paper on the subject of galvanic electricity, in nicholson's journal, which was followed by six others, in which he so far extended the original experiment of nicholson and carlisle, as to show that oxygen and hydrogen might be evolved from separate portions of water, though vegetable and even animal substances intervened; and conceiving that all decompositions might be _polar_, he electrized different compounds at the different extremities, and found that sulphur and metallic bodies appeared at the _negative_ pole, and oxygen and azote at the _positive_ pole, though the bodies furnishing them were separated from each other. here was the dawn of the electro-chemical theory. in a letter to mr. gilbert, already printed in these memoirs,[ ] he announced his opinion that galvanism is a process principally chemical; and in a subsequent communication[ ] to the same gentleman, written on the eve of his departure from bristol to the royal institution, we discover a farther developement of the same theory, which, although modified by future researches, became, as we shall hereafter find, materially instrumental in establishing juster views of the nature of voltaic action. [ ] see page . [ ] page . as soon as it was discovered that galvanic power might be excited by the contact of metals, without the interposition of animal organs, it was imagined that the electricity was set in motion by the contact of bodies possessing different conducting powers, without any reference to the chemical action which accompanied the process. this theory was naturally suggested by the fact discovered by mr. bennett several years before--that _electricity is excited by the mere contact of different metals_: thus, when a plate of copper and another of zinc, each furnished with an insulating glass handle, are made to touch by their flat surfaces, the zinc, after separation, exhibits _positive_, and the copper _negative_ electricity. in this case, it is fair to conclude that a certain quantity of electricity had moved from the copper to the zinc. on trying other metals, volta found that similar phenomena arose; from which property such bodies have been denominated "_motors_" of electricity, and the process which takes place _electro-motion_: terms which have since been sanctioned and adopted by davy. it is on this transference of electricity from one surface to another, by simple contact, that volta explains the action of the pile invented by himself, as well as that of all similar arrangements. the interposed fluids, on this hypothesis, have no effect as chemical agents, in producing the phenomena; they merely act as conductors of the electricity. we have seen how early davy had observed the intimate connexion subsisting between the electrical effect, and the chemical changes going on in the pile, and that he accordingly drew the conclusion of the dependence of the one upon the other. in fact, the most powerful voltaic combinations are those formed by substances that act chemically upon each other with the greatest energy; while such as undergo no chemical change exhibit no electrical powers: thus zinc, copper, and nitric acid form a powerful battery; whilst silver, gold, and water, which do not act upon each other, produce no sensible effect in a series of the same number. although, in this obscure region of research, we are as yet unable to discover the nature of the power by which electricity is accumulated, it was a considerable step towards a true theory to have ascertained the insufficiency of the proposition that had been offered in explanation of the phenomena. an investigation into the chemical activity of the pile led davy to the discovery of a new series of facts, to which we find an allusion in his former letters to mr. gilbert, and which subsequently formed the basis of his first communication read before the royal society on the th of june in the same year. all the combinations analogous to the voltaic pile had hitherto consisted of a series containing, at least, _two_ metallic bodies, (or one metal and charcoal,) and a stratum of fluid. davy discovered that an accumulation of galvanic energy, exactly similar to that in the common pile, might be produced by the arrangement of _single_ metallic plates with _different_ strata of fluids; so that, instead of composing a battery with _two_ metals and _one_ fluid, he succeeded in constructing it with _one_ metal and _two_ fluids; provided always that oxidation, or some equivalent chemical change, should proceed on one of the metallic surfaces only. in describing these combinations of a single metal with two fluids, he divides them into three classes, following in the arrangement the order of time with regard to their discovery. in the first class, one side of the metallic plate is oxidated; in the second, a sulphuret is formed on one of its surfaces; and in the third, both sides are acted upon, the metal becoming a _sulphuret_ on one of its surfaces, and an _oxide_ on the other. the apparatus which he employed for these experiments is preserved in the laboratory of the royal institution. it consists of a trough, containing grooves capable of receiving the edges of the different plates necessary for the arrangement, one half of which are composed of horn, the other half of some one metal. when the apparatus was used, the cells were filled, in the galvanic order, with the different solutions, according to the class of the combination, and connected in pairs with each other by slips of moistened cloth carried over the non-conducting plates. at the meeting of the royal society, following that on which the above interesting facts were communicated, dr. wollaston presented a memoir of considerable importance, entitled, "experiments on the chemical production and agency of electricity;" in which he strongly advocates the truth of that theory which recognises metallic oxidation as the _primary_ cause of the voltaic phenomena. this paper is also farther important as it proves, by most ingeniously devised experiments, not only the similarity of the means by which both common and galvanic electricity are excited, but also the resemblance existing between their effects; showing, in fact, that they are both essentially the same, and confirming the opinion, that all the apparent differences may depend upon differences in intensity and quantity. acting upon this principle, dr. wollaston succeeded in producing a very close imitation of the chemical action of galvanism by common electricity; such, for example, as the decomposition of water, and other effects of oxidation and deoxidation.[ ] in the prosecution of this train of research, he displays, in a very striking manner, that attention to minute arrangement which so remarkably characterised all his manipulations. i particularly allude to the expedients by which he reduced the extremity of a gold wire, in order to apportion the strength of the electric charge to the quantity of water submitted to its influence. [ ] m. bonijol of geneva has lately succeeded in effecting the decomposition of _potash_ and the _chloride of silver_ by ordinary electricity. his process consists in placing these substances in a very narrow glass tube, and in then passing a series of electric sparks from the ordinary machine through them. the electricity was conducted into the tube by means of two metallic wires fixed into the ends. when a quick succession of electric sparks had taken place for about five or ten minutes, the tube containing chloride of silver was found to contain reduced silver; and when potash had been submitted to the electric current, then the potassium was seen to take fire as it was produced. the same philosopher has likewise contrived to decompose water by atmospheric electricity. the electricity, in this case, is collected from the atmosphere by means of a very fine point fixed at the extremity of an insulated rod; the latter is connected with the apparatus, in which the water is to be decomposed, by a metallic wire, of which the diameter does not exceed - th of an inch. in this way the decomposition of the water proceeds in a continuous and rapid manner, although the atmospheric electricity be not strong. stormy weather, it is said, is quite sufficient for the purpose.--_bib. univers._ , p. . and _royal institution journal_, no. . although it is now very generally admitted, that the chemical agency of the fluids upon the metals employed is highly essential to the maintenance of voltaic action, there still remains considerable doubt as to how far we are entitled to regard it as the first in the order of phenomena. at a later period of his researches, davy suggested as a correction, or rather modification, of the theory of volta, that the electro-motion produced by the contact of the metals might be the primary cause of the chemical changes; and that such changes were in no other way efficient, than in restoring the electric equilibrium thus disturbed: it was farther held, that this equilibrium could not be permanent, that it could in fact be only momentary; since, in consequence of the imperfect conducting power of the interposed fluid, the zinc and copper-plates, by their electro-motive power, would again assume their opposite states of electricity; and that these alternate changes would occur, as long as any of the fluid remained undecomposed. in a voltaic arrangement, then, there would appear to exist, if the expression may be allowed, a kind of electrical seesaw; the apposition of the metals destroying the equilibrium, and the resulting chemical changes again restoring it. it has, however, been very justly observed, that the application of electricity, as an instrument of chemical decomposition, has most fortunately no connexion with such theories, and that the study of its effects may be carried on without reference to any hypothetical notions concerning the origin of the phenomena. an interval of nearly five years had elapsed between the first communication which davy made on this subject, and the bakerian lecture which is immediately to be considered. during this period several new facts had been added by different experimentalists, but they were scattered, disjointed, and totally unconnected with each other by any rational analogies. the constant appearance of acid and alkaline matter in pure water, when submitted to the influence of the voltaic pile, gave rise to the most extravagant speculations and discordant hypotheses. various statements were made, both in italy and england, respecting the _generation_ of muriatic acid, and that of the fixed alkalies, under these circumstances. mr. sylvester affirmed, that if two separate portions of water were electrised out of the contact of substances containing alkaline or acid matter, acid and alkali would, nevertheless, be produced. some philosophers sought to explain the phenomenon from the salts contained in the fluids of the trough, which they imagined might, by some unsuspected channel, find their way into the water under examination. others believed that they were actually _generated_ by the union of the electric fluid with the water, or with one or both of its elements; so that, up to the time of davy's masterly researches, the subject was involved in the greatest obscurity; and whether the saline matter was liberated from unknown combinations, or at once formed by the union of its elements, was a question upon which the greatest chemists entertained different opinions. the bakerian lecture, read before the royal society on the th of november , not only set this question for ever at rest, but unfolded the mysteries of general voltaic action; and, as far as theory goes, may almost be said to have perfected our knowledge of the chemical agencies of the pile. this grand display of scientific light burst upon europe like a splendid meteor, throwing its radiance into the deepest recesses, and opening to the view of the philosopher new and unexpected regions. i shall endeavour to offer as popular a review of this celebrated memoir, as the abstruse and complicated nature of its subjects will allow; and i shall be careful in pointing out the successive stages of the enquiry; for we are all too much in the habit of exclusively looking after results; whereas an examination of the steps by which they were attained is far more important, not only to the fame of the discoverer, but to ourselves, as the means of instruction. the subjects investigated in this memoir are arranged under the following divisions. . "on the changes produced in water by electricity. . "on the agencies of electricity in the decomposition of various compound bodies. . "on the transfer of certain constituent parts of bodies by the action of electricity. . "on the passage of acids, alkalies, and other substances, through various attracting chemical menstrua, by means of electricity. . "some general observations on these phenomena, and on the mode of decomposition and transition. . "on the general principles of the chemical changes produced by electricity. . "on the relations between the electrical energies of bodies and their chemical affinities. . "on the mode of action of the pile of volta, with experimental elucidations. . "on some general illustrations and applications of the foregoing facts and principles." with respect to the first of these divisions, comprehending a history of the changes produced in water by electricity, it is worthy of particular notice, that as early as the year , while residing at bristol, davy had discovered that when separate portions of distilled water, filling two glass tubes connected by moist bladders, or any moist animal or vegetable substance, were submitted to the electrical action of the voltaic pile, by means of gold wires, a _nitro-muriatic_ solution of gold appeared in the tube containing the positive wire, and a solution of soda in the opposite tube; but he soon ascertained that the muriatic acid owed its appearance to the animal or vegetable matters employed; for when the same fibres of cotton were used in successive experiments, and washed after every process in a weak solution of nitric acid, the water in the apparatus containing them, though acted upon for a great length of time with a very strong power, produced no effect upon a solution of nitrate of silver. in every case in which he had procured much soda, the glass[ ] at the point of contact with the wire seemed considerably eroded; when by substituting an agate for a glass cup, no fixed saline matter could be obtained. its source therefore, in the former case, was evidently the glass. [ ] it is perhaps a fact not very generally known, that glass, to a certain extent, is decomposable by water: if some of it in a powdered state be triturated with distilled water, in a short time the turmeric test will indicate a portion of alkali in solution. with respect to mr. sylvester's experiment, already noticed, it was sufficient to say that he conducted his process in a vessel of _pipe-clay_, which not only contains lime, but may also include in its composition some of the combinations of a fixed alkali. on resuming the enquiry, it was davy's first care to remove every possible source of impurity: he accordingly procured cups of agate, which, previously to being filled, were boiled for several hours in distilled water; and a piece of very white and transparent _amianthus_, a substance first proposed for this purpose by dr. wollaston, having been similarly purified, was made to connect the vessels together. thus was every apparent source of fallacy removed; but still, after having been exposed to voltaic action for forty-eight hours, the water in the positive cup gave indications of muriatic acid, and that in the negative cup, of soda! the result was as embarrassing as it was unexpected; but it was far from convincing him that the bodies thus obtained were _generated_:--but whence arose the saline matter? did the agate, after every precaution, still contain some very minute portion of saline matter, not easily discoverable by chemical tests? to determine this question, the experiment was repeated a second, a third, and a fourth time: the quantities of saline matter diminished in every successive operation, which sufficiently proved that the agate must at least have been _one_ of the sources sought for; but four additional repetitions of the process convinced the operator that it could not be the only one; that there must exist some other source from which the alkali proceeded, since it continued to appear to the last, in quantities sufficiently distinct, and apparently equal, in every experiment. this was extremely perplexing: every precaution had been taken--the agate cups had even been included in glass vessels, out of the reach of the circulating air--all the acting materials had been repeatedly washed with distilled water; and no part of them in contact with the fluid had ever touched the fingers. the water itself then, however pure it might appear, must have furnished the alkali. the experiments were repeated in cones of the purest gold, and the water contained in them was submitted to voltaic action for fourteen hours; the result was, that the acid increased in quantity as the experiment proceeded, and at length became even sour to the taste. on the contrary, the alkaline properties of the fluid in the opposite cone shortly obtained a certain intensity, and remained stationary. on the application of heat, the alkaline indications became less vivid, although there always remained, after the operation, sufficient evidence to prove that a portion at least was fixed, although probably mixed with ammonia. the acid, as far as its properties could be examined, agreed with those of pure nitrous acid, having an excess of nitrous gas. it was now impossible to doubt that the water held in solution some substance which was capable of yielding alkaline matter, but which, from the minuteness of its quantity, had soon been exhausted. the next step, therefore, was to submit the water to a still more rigorous examination, which he did by evaporating it in a vessel of silver; when he had the satisfaction to discover the - th of a grain of saline matter. the water, thus purified in a vessel of silver, was again subjected to voltaic action in the cones of gold. after two hours, there was only the slightest possible indication of alkali; and this was not, as before, _fixed_, but entirely _volatile_. in every one of these experiments, acid matter had been produced, and it always presented the character of nitrous acid. two of the great sources of foreign matter had been detected and removed, viz. the vessels, and the water employed; it still however remained to be explained, how nitrous acid and ammonia could be produced in cases where pure water and pure vessels had been used. in no part of this elaborate enquiry is the penetration of davy more striking, than in his reasonings upon this problem, and in the beautiful experiments which his sagacity suggested for its solution. it occurred to him, that the nascent oxygen and hydrogen of the water might respectively combine with a portion of the nitrogen of the common air, which is constantly dissolved in that fluid; but if this were the case, how did it happen that the production of nitrous acid was progressive, while that of the alkali was limited? the experiments of dr. priestley, on the absorption of gases by water, at once suggested themselves to his mind as being capable of solving this last difficulty; for that distinguished philosopher had shown, that hydrogen, during its solution in water, expelled the nitrogen, whereas oxygen and nitrogen were capable of coexisting in a state of solution in that fluid. it was, however, necessary to confirm the truth of this explanation by experiment, and he accordingly introduced the two cones of gold, containing purified water, under the receiver of an air-pump; the exhaustion was effected, and the voltaic pile brought to act upon the water thus circumstanced; after eighteen hours the result was examined, when the water in the negative cone produced no effect upon prepared litmus, but that in the positive vessel did give it a tinge of red barely perceptible. had his series of experiments terminated here, the truth of his conclusions would have been established by the comparatively small proportion of acid formed in this latter experiment; but he determined to repeat it under circumstances, if possible, still more unexceptionable and conclusive. having, therefore, arranged the apparatus as before, he exhausted the receiver, and then filled it with hydrogen gas from a convenient air-holder; he made even a second exhaustion, to ensure the highest accuracy, and then again introduced carefully prepared hydrogen. the voltaic process was continued during twenty-four hours, and at the end of that period it was found that neither the water in the positive nor in the negative vessels altered the tint of litmus in the slightest degree. thus did he succeed in exposing the three great sources of fallacy which had so long misled chemists, with regard to the generation of acid and alkaline matter in voltaic experiments, viz.--the impurities of the vessels--the foreign matter contained in the water--and the compounds generated by the combination of the nitrogen of atmospheric air with the elements evolved from water; and thus did he establish, by an unbroken chain of incontrovertible evidence, the important truth, that "water, chemically pure, is decomposed by electricity into gaseous matter alone--into oxygen and hydrogen." out of the foregoing train of research very naturally sprang the consideration of the _decomposing agencies of electricity_. it had been constantly observed, that, in all electrical changes connected with the presence of acid and alkaline matter, the former uniformly collected around the positive, and the latter around the negative surface of the apparatus. in one of the earliest experiments, davy had also noticed that glass underwent decomposition, and that its alkali always passed to the negative surface. he was, therefore, led to enquire whether, through electrical agency, different solid earthy compounds, insoluble, or soluble with difficulty in water, might not be made to undergo a similar decomposition. we shall find that the results of the trials were decisive and satisfactory. for conducting experiments of this description, he hit upon the happy expedient of constructing the cups with the materials which he wished to submit to experiment, and then by introducing water into them, and forming the necessary connexion by means of asbestus, he completed the voltaic circuit. in this manner he submitted to experiment _sulphate of lime_, _sulphate of strontia_, _fluate of lime_, _sulphate of baryta_, &c. and with analogous results; the acid element in each case passing to the positive, and the earthy base to the negative cup. as, in the above experiments, the bodies under examination were presented in considerable masses, and exposed large surfaces to the electric action, it became necessary to enquire whether minute portions of acid and alkaline matter could, by the same agency, be disengaged from solid combinations. this point was very readily elucidated. a piece of fine grained basalt, which, by a previous analysis, had been found to contain · per cent. of soda, nearly · of muriatic acid, and fifteen parts of lime, having been divided into two properly-shaped pieces, and a cavity, capable of containing twelve grains of water, been drilled in each, was submitted, as in former experiments, to the action of the pile. at the end of ten hours, the result was examined with care, when it appeared that the positively electrified water had the strong smell of oxymuriatic acid, and copiously precipitated nitrate of silver; while that which was negative affected turmeric, and left by evaporation a residuum which appeared to consist of lime and soda. a part of a specimen of compact zeolite from the giants' causeway, and vitreous lava from Ã�tna, were each treated in a similar manner, and with results equally satisfactory. having thus settled the question with regard to the disengagement of the saline parts of bodies insoluble in water, he proceeded to extend and multiply his experiments on soluble compounds, the decomposition of which, as might have been supposed, always proceeded with greater rapidity, and furnished results more perfectly distinct. in these processes he employed the agate cups, with platina wires, connected by amianthus moistened with pure water; the solutions were introduced into these cups, and the electrifying power applied in the manner already described. in this way, _sulphate of potash_, _sulphate of soda_, _nitrate of potash_, _phosphate of soda_, &c. were respectively examined; and in every case the acid, after a certain interval, collected in the cup containing the positive wire, and the alkalies and earths in that containing the negative wire. when metallic solutions were employed, metallic crystals or depositions were formed on the negative wire, and oxide was likewise deposited around it, while a great excess of acid was found in the opposite cup. with respect to the transfer of the constituent parts of bodies by electric action, several original experiments were instituted, and some important conclusions established. several facts had been stated, which rendered it probable that the saline elements evolved in decompositions by electricity, were capable of being transferred from one electrified surface to another, according to their usual order of arrangement; but to demonstrate this clearly, farther researches were required, and davy proceeded to supply the necessary evidence. he connected one of the cups of sulphate of lime before mentioned, with a cup of agate, by means of asbestus, and filling them with purified water, connected them with the battery. in about four hours, a strong solution of lime was found in the agate cup, and sulphuric acid in the cup of sulphate of lime. by reversing the order of arrangement, and carrying on the process during a similar period, the sulphuric acid appeared in the agate cup, and the lime in the opposite vessel. in both these experiments (the acid in the one case, and the lime in the other), the elements of the substance must have passed, in an imperceptible form, along the connecting line of asbestus into the opposite vessel. many trials were made with other saline bodies, and with results equally satisfactory; the base always passing into the vessel rendered negative, and the acid into that which was positive. the time required for these transmissions appeared to be, _cæteris paribus_, in some proportion to the length of the intermediate volume of water. in the farther prosecution of the enquiry, davy discovered a still more extraordinary series of facts. in the first place, he found that the contact of the saline solution with a metallic surface was not in the least necessary for its decomposition. he introduced purified water into two glass tubes, and connected with them, by means of amianthus, a vessel containing a solution of muriate of potash. in this case, the saline matter was distant from each of the wires at least two-thirds of an inch; and yet alkaline matter soon appeared in one tube, and acid matter in the other; and in sixteen hours moderately strong solutions of potash and muriatic acid had been formed. the discovery of this fact became the key to that of others. he very naturally proceeded to enquire into the progress of the transfer, and into the course of the acid and alkaline elements; when, by the use of litmus and turmeric, he arrived at the following conclusion,--that acids and alkalies, during their electrical transference, passed through water containing vegetable colours without effecting in them any change. from which we are led to the consideration of the fourth division of the subject, viz. "on the passage of acids, alkalies, and other substances, through various attracting chemical menstrua, by electricity." as soon as it was discovered that a power generated by the voltaic pile was capable of destroying elective affinity in the vicinity of the metallic points, it seemed reasonable to suppose, that the same power might also destroy it, or at least suspend its operation, throughout the whole of the circuit. the truth of such a supposition was at once placed beyond all doubt by the following very striking experiment. three tubes, the first containing a solution of _sulphate of potash_, the second a weak solution of _ammonia_, and the third, _pure water_, each being connected with the other in the usual manner by amianthus, were arranged in relation to the pile, as follow:--the _sulphate of potash_ was placed in contact with the negatively electrified point, the _pure water_ with the positively electrified point, while the solution of _ammonia_ was made the middle link of the conducting chain; so that no sulphuric acid could pass to the positive point in the distilled water, without passing through the ammoniacal solution. in less than five minutes after the electric current had been completed, it was found, by means of litmus paper, that acid was in the act of collecting around the positive point; and in half an hour the result was sufficiently distinct for accurate examination. other experiments were made with a solution of lime, and with weak solutions of potash and soda, and the results were analogous. muriatic acid, from muriate of soda, and nitric acid, from nitrate of potash, were also transmitted through concentrated alkaline menstrua, under similar circumstances, and with like effects. davy also made several experiments on the transition of alkaline and acid matter, through different neutro-saline solutions, the results of which were exactly such as theory would have anticipated. in conducting, however, these experiments of electrical transference, there would appear to be one condition essential to their success, viz. that the solution contained in the intermediate vessel should not be capable of forming an insoluble compound with the substance transmitted through it: thus, for example, davy found that _strontia_ and _baryta_ passed, like the other alkaline substances, very readily through muriatic and nitric acids; and _vice versâ_, that these acids passed with equal facility through aqueous solutions of the earths in question; but when it was attempted to pass _sulphuric_ acid through the same earthy solutions, or to pass the earths through the sulphuric acid, that then the results were of a very different character: the sulphuric acid, in its passage through the barytic solution, was arrested in its progress by the earthy body, and falling down as an insoluble compound with it, was carried out of the sphere of the electrical action, by which the power of transfer was destroyed. the same phenomena occurred whenever he attempted to pass muriatic acid through a solution of sulphate of silver. we now come to the next division--viz. "some general observations on these phenomena, and on the mode of decomposition and transition." davy considers that it will be a general expression of the facts relating to the changes and transitions by electricity, to say, that "hydrogen, the alkaline substances, the metals, and certain oxides, are attracted by negatively electrified, and repelled by positively electrified metallic surfaces; and on the contrary, that oxygen and acid substances are attracted by positively electrified, and repelled by negatively electrified metallic surfaces." and moreover, that these "attractive and repulsive forces are sufficiently energetic to destroy or suspend the usual operation of elective affinity." amidst all these wonderful phenomena, that perhaps which excites our greatest astonishment is the fact of the transfer of ponderable matter to a considerable distance, through intervening substances, and in a form that escapes the cognizance of our senses! upon this question, davy offers the following remarks:--"it is," says he, "very natural to suppose, that the repellent and attractive energies are communicated from one particle to another particle of the same kind, so as to establish a conducting chain in the fluid; and that the locomotion takes place in consequence: thus, in all the instances in which i examined alkaline solutions through which acids had been transmitted, i always found acid in them, as long as any acid matter remained at the original source. in time, by the attractive power of the positive surface, the decomposition and transfer undoubtedly become complete; but this does not affect the conclusion. in cases of the separation of the constituents of water, and of solutions of neutral salts forming the whole of the chain, there may possibly be a succession of decompositions and recompositions throughout the fluid." we are next brought to a very important point in the enquiry--viz. "the consideration of the general principles of the chemical changes produced by electricity." the experiment of mr. bennett, already alluded to, had shown that many bodies, when brought into contact, and afterwards separated from each other, exhibited signs of opposite states of electricity: but it is to the investigations of m. volta that we are indebted for the clear developement of the fact; for he has distinctly proved it in the case of copper and zinc, and other metallic combinations, and he supposed that it might also take place with regard to metals and fluids. in a series of experiments, made in the year , on the construction of electrical combinations, by means of alternations of single metallic plates, and different strata of fluids, as explained upon a former occasion,[ ] davy had observed that, when acid and alkaline solutions were employed as the elements of these voltaic combinations, the alkaline solutions always received the electricity from, and the acid always transmitted it to the metal. these principles seem to bear an immediate relation to those general phenomena of decomposition and transfer, which have been the subject of the preceding details. [ ] page . in the most simple case of electrical action, the alkali which receives electricity from the metal would necessarily, on being separated from it, appear _positive_; whilst the acid, under similar circumstances, would be _negative_; and these bodies having respectively, with regard to the metal, that which may be called a positive and a negative electrical energy, in their repellent and attractive functions, would seem to be governed by the common laws of electrical attraction and repulsion; the body possessing the positive energy being repelled by positively electrified surfaces, and that possessing the negative influence following the contrary order. davy made a number of experiments with the view of elucidating this idea, and of extending its application; and, in all cases, their results tended, in a most remarkable manner, to confirm the analogy. he proceeded, by means of very delicate instruments, to ascertain the electrical states of single insulated acid and alkaline solutions, after their contact with metals; but the sources of errors were so numerous, as to render the results far from being satisfactory; but in experiments on dry and solid bodies, the embarrassments arising from evaporation, chemical action, &c. did not occur. when perfectly dry oxalic, succinic, benzoic, or boracic acid, either in the form of powder or crystals, were touched upon an extended surface with a plate of copper, insulated by a glass handle, the copper was found positive, the acid negative. when again metallic plates were made to touch dry lime, strontia, or magnesia, they became negative: in these latter experiments the effect was exceedingly satisfactory and distinct; a single contact upon a large surface being sufficient to communicate a considerable charge. numerous other trials were made, and the results confirmed the principle; and moreover proved, as might have been expected, that bodies possessing electrical conditions with regard to one and the same body, possessed them with regard to each other: for instance, a dry piece of lime became positively electrical by repeated contact with crystals of oxalic acid. these results led him to reason more fully upon the "relations between the electrical energies of bodies and their chemical affinities." as the chemical attraction subsisting between two bodies seems to be destroyed by giving to one of them an electrical condition opposite to that which it naturally possesses; and since the substances that combine chemically, as far as can be ascertained, exhibit opposite states of electricity, the relations between this energy and chemical affinity would appear to be sufficiently evident to warrant the conclusion at which davy arrived, viz. that "the combinations and decompositions by electricity were referable to the law of electrical attractions and repulsions;" from which he advanced to the still more important step--"that chemical and electrical attractions were produced by the same cause, acting in one case on particles, in the other on masses." from these views, he is led to propose the electrical powers, or the forces required to disunite the elements of bodies, as a test or measure of the intensity of chemical attraction. an accurate investigation into this connexion, which may be called the _electro-dynamic_ relations of bodies to their combining masses or proportional numbers, would be the first step towards fixing the science of chemistry on the permanent foundation of the mathematics. if, then, the power of electrical attraction and repulsion be identified with chemical affinity, or rather, if both be dependent upon the same cause, it will follow that two bodies which are naturally in opposite electrical states, may have these states sufficiently exalted to give them an attractive power superior to the cohesive force opposed to their union; when a combination will take place which will be more or less energetic, as the opposed forces are more or less equally balanced. again, when two bodies, repellent of each other, act upon a third with different degrees of the same electrical energy, the combination will be determined by the degree; or, if bodies having different degrees of the same electrical energy with respect to a third, have likewise different energies with respect to each other, there may be such a balance of attracting and repelling forces as to produce a triple compound; and by the extension of this reasoning, complicated chemical union may be easily explained. whenever bodies brought by artificial means into a high state of opposite electricities are made to restore the equilibrium, heat and light are the common consequences. it is perhaps an additional circumstance in favour of the theory to state, that heat and light are likewise the results of all intense chemical action. and as in certain forms of the voltaic battery, where large quantities of electricity of low intensity act, heat without light is produced; so in slow chemical combinations there is an increase of temperature without any luminous appearance. the effect of heat in producing combination may be easily explained according to these ideas; it not only gives more freedom of motion to the particles, but in a number of cases it seems to exalt the electrical energies of bodies:--glass, the tourmaline, sulphur, and some others, afford familiar instances of this latter species of energy. in general, when the different energies are strong and in perfect equilibrium, the combination ought to be quick, the heat and light intense, and the new compound in a neutral state. this would seem to be the case in the combination of oxygen and hydrogen, which form water, a body apparently neutral in electrical energy to most others; and also in the circumstances of the union of the strong alkalies and acids. but where one energy is feeble, and the other strong, all the effects must be less vivid; and the compound, instead of being neutral, ought to exhibit the excess of the stronger energy. the grand principle thus developed may enable us to obtain new and useful indications of the composition of bodies, by ascertaining the character of their electrical energies; and we now find, in most modern works of chemistry, that bodies are arranged according to their natural electrical relations; and are said to be electro-positive, or electro-negative, according to their polarities. the advantage of such an arrangement must be freely acknowledged, for it has been the means of establishing analogies[ ] of the utmost importance in chemistry, of which i shall adduce some striking examples in a subsequent part of the present work, when i shall endeavour to offer a general view of the revolution which chemical science has undergone during the investigations of davy, and contemporary philosophers. [ ] it will be sufficient for my present purpose to point out those existing between _chlorine_, _iodine_, and _bromine_. after some further enquiries into the theory of the voltaic pile,[ ] to which an allusion has been already made, the author offers additional reasons for supposing the decomposition of the chemical menstrua essential to the continued electro-motion of the pile; and if the fluid medium could be a substance incapable of decomposition, there is every reason to believe the equilibrium would be restored, and the motion of the electricity cease. having shown the effects of _induction_, in increasing the electricity of the opposite plates, he arrives at the important conclusion, that in a voltaic arrangement the _intensity of the electricity increases with the number, but the quantity with the size of the plates_. a theory which was subsequently confirmed by the experiments of mr. children. [ ] see page . the paper concludes with "some general illustrations and applications of the foregoing facts and principles," and which the author thinks will readily suggest themselves to the philosophical enquirer. they offer, for instance, very easy methods of separating acid and alkaline matter, where they exist in combination in mineral substances; and, in like manner, they suggest the application of electrical powers for effecting the decomposition of animal and vegetable bodies. on exposing a piece of muscular fibre to the action of the battery, he found that potash, soda, ammonia, lime, and oxide of iron, were evolved on the negative side, and the three mineral, together with the phosphoric, acids, were given out on the positive side. a laurel leaf, similarly treated, yielded to the negative vessel resin, alkali, and lime; while in the positive one there collected a clear fluid, which had the smell of peach-blossoms, and which, when neutralized by potash, gave a blue-green precipitate to a solution of sulphate of iron; so that it must have contained _prussic acid_. a small plant of mint, in a state of healthy vegetation, on being made the medium of connection in the battery, yielded potash and lime to the water negatively electrified, and acid to that positively electrified. the plant recovered after the process; but a similar one, that had been electrified during a longer period, faded and died. these facts would seem to show, that the electrical powers of decomposition even act upon vegetable matter in its living condition; and phenomena are not wanting to show that they operate also on the system of living animals. when the fingers, after having been carefully washed with pure water, are brought in contact with this fluid in the positive part of the circuit, acid matter is rapidly developed, having the character of a mixture of muriatic, phosphoric, and sulphuric acids; and if a similar trial be made in the negative part, fixed alkaline matter is as quickly developed.[ ] [ ] reflecting upon this and similar facts, it has occurred to me that voltaic electricity might be applied for removing the blue colour in the skin, occasioned by the internal use of nitrate of silver. i hope to be able very shortly to submit this theory to the test. davy thinks that the acid and alkaline taste produced upon the tongue during galvanic experiments, depends upon the decomposition of the saline matter contained in the living animal substance, and perhaps in the saliva; and he farther observes that, as acid and alkaline substances are thus evidently capable of being separated from their combinations in living systems by electrical powers, there is reason to believe that, by converse methods, they might also be introduced into the animal economy, or made to pass through the animal organs; and the same thing may be supposed of metallic oxides; and that these ideas ought to lead to some new investigations in medicine and physiology. he thinks it by no means improbable, that the electrical decomposition of the neutral salts, in different cases, may admit of economical applications; and that well-burnt charcoal and plumbago, or charcoal and iron, might be made the exciting powers for such a purpose. such an arrangement, if erected upon a scale sufficiently extensive, with the medium of a neutro-saline solution, would, in his opinion, produce large quantities of acids and alkalies with very little trouble or expense. alterations in chemical equilibrium are constantly taking place in nature, and he thinks it probable that the electric influence, in its faculties of decomposition and transference, may considerably interfere with the chemical changes occurring in different parts of our system. the electrical appearances which precede earthquakes and volcanic eruptions, and which have been described by the greater number of the observers of these awful events, admit also of easy explanation on the principles that have been stated. besides the cases of sudden and violent change, he considers there must be constant and tranquil alterations, of which electricity, produced in the interior strata of the globe, is the active cause: thus, where _pyritous_ strata and strata of _coal-blende_ occur,--where the pure metals or the sulphurets are found in contact with each other, or with any conducting substances,--and where different strata contain different saline menstrua, he thinks electricity must be continually manifested; and it is probable that many mineral formations have been materially influenced, or even occasioned, by its agencies. in an experiment which he performed of electrifying a mixed solution of the muriates of iron, copper, tin, and cobalt, contained in a positive vessel, all the four oxides passed along the connecting asbestus into a positive vessel filled with distilled water, while a yellow metallic crust formed on the wire, and the oxides arranged themselves in a mixed state around the base of it. in another experiment, in which carbonate of copper was diffused through water in a state of minute division, and a negative wire was placed in a small perforated cube of zeolite in the water, green crystals collected round the cube; the particles not being capable of penetrating it. by a multiplication of such instances, davy remarks, that the electrical power of transference may be easily conceived to apply to the explanation of some of the principal and most mysterious facts in geology;[ ] and by imagining a scale of feeble powers, it would be easy to account for the association of the insoluble metallic and earthy compounds containing acids. [ ] during the contentions of the neptunists and plutonists, alluded to in a former part of this work, specimens were produced exhibiting the intermixture of mineral bodies, which was completely hostile to all theory. these anomalies now receive a plausible explanation from the agencies of voltaic electricity. "natural electricity," observes our philosopher, "has hitherto been little investigated, except in the case of its evident and powerful concentration in the atmosphere. its slow and silent operations in every part of the surface will probably be found more immediately and importantly connected with the order and economy of nature; and investigations on this subject can hardly fail to enlighten our philosophical systems of the earth, and may possibly place new powers within our reach." thus concludes one of the most masterly and powerful productions of scientific genius. i may perhaps have been considered prolix in recording the progressive researches by which he arrived at his results; but let it be remembered, that the great fame of davy, as an experimental philosopher, rests upon this single memoir; and though the secondary results to be hereafter considered, may be more dazzling to ordinary minds, yet in the judgment of every scientific observer, they must appear far less glorious than the discovery of the primitive laws. let me ask whether sir isaac newton does not deserve greater fame for his invention of fluxions, than for the calculations performed by the application of them? i do not hesitate in comparing these great philosophers, since each has enlightened us by discoveries alike effected by means invented by himself. not only did both unlock the caskets of nature, but they had the superior merit of planning and constructing the key. i challenge those, who have carefully followed me through the details of the preceding memoir, to show a single instance in which accident, so mainly contributory to former discoveries in electricity, had any share in conducting its author to truth. step by step did he, with philosophic caution and unwearied perseverance, unfold all the particular phenomena and details of his subject; his genius then took flight, and with an eagle's eye caught the plan of the whole.--a new science has been thus created; and so important and extensive are its applications, so boundless and sublime its views, that we may fairly anticipate the fulfilment of those prophetic words of dr. priestley, who, in the preface to his history of electricity,[ ] exclaims--"electricity seems to be giving us an inlet into the internal structure of bodies, on which all their sensible properties depend. by pursuing this new light, therefore, the bounds of natural science may possibly be extended beyond what we can now form any idea of. new worlds may open to our view, and the glory of the great sir isaac newton himself, and all his contemporaries, be eclipsed by a new set of philosophers, in quite a new field of speculation. could that great man revisit the earth, and view the experiments of the present race of electricians, he would be no less amazed than roger bacon, or sir francis, would have been at his." in our turn we may ask, what would be the astonishment--what the delight of dr. priestley, could he now witness the successful results of voltaic research?--and what would he say of that mighty genius who has demonstrated the relations of electrical energy to the general laws of chemical action?[ ] it was his good fortune to have witnessed the discovery which identified electricity with the lightning of the thunder cloud: what would he have said of that which identified it with the magnetism of the earth! of this at least we may be certain, that he would have expunged from his history the passage in which he observes--"electrical discoveries have been made so much by accident, that it is more the powers of nature, than of human genius, that excite our wonders with respect to them." [ ] the history and present state of electricity; by jos. priestley, ll.d. f.r.s., &c. london, . [ ] dr. priestley augured much from the talents of davy. after the publication of his first paper on galvanism, he wrote to him from america, and expressed the pleasure he felt on finding his favourite subject in such able hands. priestley died in , and therefore did not witness davy's success. chapter vii. the unfair rivalry of philosophers.--bonaparte the patron of science.--he liberates dolomieu.--he founds a prize for the encouragement of electric researches.--his letter to the minister of the interior.--proceedings of the institute.--the prize is conferred on davy.--the bakerian lecture of .--the decomposition of the fixed alkalies--potassium--sodium.--the questions to which the discovery gave rise.--interesting extracts from the manuscript notes of the laboratory.--potash decomposed by a chemical process.--letters to children, and pepys.--the true nature of potash discovered.--whether ammonia contains oxygen.--davy's severe illness.--he recovers and resumes his labours.--his fishing costume.--he decomposes the earths.--important views to which the discovery has led. it must be confessed that there has too frequently existed amongst philosophers a strange and ungenerous disposition to undervalue the labours of their contemporaries. if a discovery be made, its truth and importance are first questioned; and should these be established, then its originality becomes a subject of dispute. truth, although she may have been rarely held fast, has been frequently touched[ ] in the dark: it is not extraordinary, therefore, that evidence may be often strained from the writings of philosophers in support of prior claims to late discoveries; but upon a candid review, these loose statements, or obscure hints, will generally be found wholly destitute of the pretensions which an unfair spirit of rivalry has too often laboured to support. many of such hints, indeed, so far from advancing the progress of truth, had never even attracted notice, until after the discoveries to which they have been supposed to relate. [ ] a most remarkable illustration of this fact occurs in the history of locke, who certainly came as near to an important discovery as any philosopher who ever caught a glimpse of a truth without seizing it; but his statement did not, in any degree, hasten the developement of that new branch of science which was reserved for the genius of dr. black to investigate, and who a century later, by the discovery of fixed air, changed the whole face of chemistry. the passage to which i allude is extracted from the life by lord king, and is so curious, that i shall give it a place in this note. "m. toinard produced a large bottle of muscat: it was clear when he set it on the table; but when he had drawn out the stopper, a multitude of little bubbles arose, and swelled the wine above the mouth of the bottle. it comes from this, that the air, which was included and disseminated in the liquor, had liberty to expand itself, and so to become visible, and, being much lighter than the liquor, to mount with great quickness.--_quere_, whether this be air new generated, or whether the springy particles of air in the fruit, out of which these fermenting liquors are drawn, have, by the artifice of nature, been pressed close together, and there by other particles fastened and held so; and whether fermentation does not loose these bands, and give them liberty to expand themselves again? take a bottle of fermenting liquor, and tie a bladder on the mouth.--_quere_, how much new air will it produce; and whether this has the quality of common air?" another instance equally illustrative of the manner in which important truths will sometimes elude notice, even after science has approached so near as to touch them, is presented in the history of the barometer. toricelli, the pupil of galileo, while reflecting upon the phenomenon which had so greatly perplexed his master, viz. that water could not be raised above thirty-two feet in the body of a pump, rightly conjectured that the water, under such circumstances, was not _drawn_, but _pushed up_ into the barrel, and that it could only be so pushed up by the force of the atmosphere. it then occurred to him, that if mercury were used instead of water, being heavier, it would not be pushed up so high by the weight of the air. so, taking a glass tube of about three feet in height, made air-tight at one end, he first filled it completely with quicksilver, and then closing it with his finger, reversed it in a basin containing that metal; when he had the gratification of seeing the liquid in the tube descend, as he had anticipated. here then was the discovery of the barometer; but it was reserved for another to find out that such an instrument had been actually invented. pascal first made the remark, that the inference of toricelli, if true, might be confirmed by carrying the mercurial tube to a considerable elevation; when the atmospheric column being diminished, that of the mercury, which was supposed to be its balance, ought likewise to be shortened in a corresponding proportion. it followed then, that a measure of the weight of the atmosphere, in all circumstances, had been obtained, and consequently that of the height of any place to which the instrument could be carried. in this manner was a discovery completed, which had for ages escaped the greatest philosophers who had made the nearest approaches to its developement. although the importance of davy's electro-chemical discoveries could not for a moment be doubted; their claims to originality, it would seem, were not admitted without some question. the works of ritter and winterl, amongst many others, were quoted to show that these philosophers had imagined or anticipated the relation between electrical powers and chemical affinities; but davy very fairly observes, in a paper read before the royal society in , that in the obscurity of the language and metaphysics of both those gentlemen, it is difficult to say what may not be found. in the ingenious though wild views of ritter, there are hints which may more readily be considered as applying to _electro-magnetism_ than to _electro-chemistry_; while winterl's _miraculous andronia_ might, with as much propriety, be considered as a type of all the chemical substances that have been since discovered, as his view of the antagonist powers (the acid and base) be regarded as an anticipation of the _electro-chemical_ theory. it would be worse than useless to speak of other works, which refer the origin of electro-chemistry to germany, sweden, and france, rather than to italy and england; and which attribute some of the views first developed by davy, to philosophers who have not, nor ever could have made any claim of the kind, since their experiments were actually not published until many years after , the date of the bakerian lecture. with regard to the judgment of posterity upon these points, but little apprehension can be entertained. i well remember, in a conversation with davy, he observed, that "a philosopher might generally discover how his labours would be appreciated in after ages, from the opinion entertained of them by contemporary foreigners, who, being unbiassed by circumstances of personality, will reduce every object to its just proportions and value." if we acknowledge the truth of such a standard, and submit the posthumous fame of davy to its measure, where is the philosopher, in our times, whose name is destined to attain a higher eminence in the history of science? let the reader only recall to his recollection the bitter animosity which france and england mutually entertained towards each other in the year , and he will be able to form some idea of the astounding impression which the bakerian lecture must have produced on the savans of paris, when, in despite of national prejudice and national vanity, it was crowned by the institute of france with the prize of the first consul! thus did the voltaic battery, in the hands of the english chemist, achieve what all the artillery of britain could never have produced--a spontaneous and willing homage to british superiority!--but let not this observation convey the slightest idea of disrespect, or be supposed to encourage any feeling to the disparagement of the chemists of france; on the contrary, it is even a question not readily answered, to which party the triumph fairly belongs,--to him who won the laurel crown, or to those who so nobly placed it on his brow? they have set an example to future ages, which may as materially advance the progress of science, as the researches which called it forth:--they have shown, to adopt the language of an eloquent writer, that "the commonwealth of science is of no party, and of no nation; that it is a pure republic, and always at peace. its shades are disturbed neither by domestic malice nor foreign levy; they resound not with the cries of faction or of public animosity. falsehood is the only enemy their inhabitants denounce; truth, and her minister reason, the only leaders they follow." i shall avail myself of this opportunity to introduce the report drawn up by m. biot, and made in the name of a commission appointed by the institute to accomplish the intention of bonaparte, who, when first consul, founded prizes for important discoveries in electricity or galvanism. it is an opinion very generally received, that despotism is hostile to the progress of philosophy--that the suspicion natural to tyranny, and the fear that light should expose its deformity, have, under such circumstances, inspired a dread of any thing approaching to freedom of enquiry. the conduct of napoleon, not only during his consulate, but even after he had assumed the purple, is in direct opposition to such an opinion. now that the excitements of national hostility have subsided, and the asperity of our feelings towards that extraordinary man has been softened by time and prosperity, we are enabled to discern the bright and sunny spots in his character. not to mention the immense plans which his genius suggested for the internal improvement of france, the annals of the institute would furnish innumerable proofs of the zeal with which he encouraged science, and promoted its interests. his liberation of dolomieu from the dungeons of tarentum was an act not only remarkable for the considerate regard it displayed for science, but for the spirit and eagerness with which it was effected. the french government had repeatedly made the most urgent demands for the liberty of one who had reflected so much credit on his country;--the danes had also directed the interference of their minister, and the king of spain had added his solicitations in vain:--no sooner, however, had the astonishing campaign which terminated by the victory of marengo, completely established the french republic, than bonaparte, in making peace with naples, stipulated for the immediate deliverance of dolomieu, as the first article of the treaty. the following letter from bonaparte, addressed to the minister of the interior, and by him transmitted to the institute, expresses the intentions of the first consul, in founding prizes for important discoveries in electricity or galvanism. "i intend, citizen minister, to found a prize, consisting of a medal of three thousand francs, (about one hundred and twenty pounds sterling,) for the best experiment which shall be made in the course of each year, on the galvanic fluid. "for this purpose, the memoirs containing the details of the said experiments shall be sent before the first of _fructidor_, to the class of the mathematical and physical sciences, which in the complimentary days shall adjudge the prize to the author of that experiment which has been most useful to the progress of science. "i also desire to give, by the way of encouragement, the sum of sixty thousand francs to the person who, by his experiments and discoveries, shall, according to the opinion of the class, advance the knowledge of electricity and galvanism as much as franklin and volta did.[ ] "foreigners of all nations are admitted to the competition. "i beg you will make known these dispositions to the president of the first class of the national institute, that it may give to these ideas such developement as may appear proper; my particular object being to encourage philosophers, and to direct their attention to this part of philosophy, which, in my opinion, may lead to great discoveries. "(signed) bonaparte." [ ] "Ã� celui qui, par ses expériences et ses découvertes, _fera à faire à l'electricité et au galvanisme un pas comparable à celui qu'ont fait faire à ces sciences franklin et volta_." my french correspondent adds, "ces soixantes mille francs n'ont pas été adjugés, _le pas n'ayant point été fait_." upon the presentation of this letter, a committee was appointed to consider the means for accomplishing the intentions of the first consul; and after expatiating upon the extensive agencies of electricity, their report concludes in the following manner:-- "to fulfill the intention of the first consul, and to give to the competition all the solemnity which the importance of the object, the nature of the prize, and the character of the founder require, the commissioners unanimously propose as follows: "the class of the mathematical and physical sciences of the national institute opens the general competition required by the first consul. "all the learned of europe, and the members and associates of the institute, are admitted to the competition. "the class does not require that the memoirs should be immediately addressed to it. every year it will crown the author of the best experiments which shall come to its knowledge, and which shall have advanced the progress of the science. "the present report, containing the letter of the first consul, shall be printed, and serve as a programme. "done at the national institute, messidor , year . "(signed) laplace, halle, coulomb, hauy. biot, reporter." it was not until twelve months after the publication of his first bakerian lecture, that davy received the intelligence that the prize of three thousand francs had been awarded him by the institute of france, for his discoveries announced in the philosophical transactions for the year . mr. poole, in a late communication, informs me that he was in london soon after the letter communicating this gratifying intelligence had been received from france; and that davy, upon showing it to him, observed, "some people say i ought not to accept this prize; and there have been foolish paragraphs in the papers to that effect; but if the two countries or governments are at war, the men of science are not. that would, indeed, be a civil war of the worst description: we should rather, through the instrumentality of men of science, soften the asperities of national hostility." after davy had been elected secretary to the royal society, he appears to have been confined to town during the autumn of , when he wrote the following letter. to thomas poole, esq. august th, . my dear poole, i am obliged to be in the neighbourhood of town during the greater part of the summer, for the purpose of correcting the press for the philosophical transactions. i made a rapid journey into cornwall for the sake of seeing my family; and it was not in my power, had i received your letter at lyme, to have accepted your kind invitation. if c---- is still with you, will you be kind enough to say to him, that i wrote nearly a week ago two letters about lectures, and not knowing where he was, i addressed them to him at different places? i wish very much he would seriously determine on this point. the managers of the royal institution are very anxious to engage him; and i think he might be of material service to the public, and of benefit to his own mind, to say nothing of the benefit his purse might also receive. in the present condition of society, his opinions in matters of taste, literature, and metaphysics, must have a healthy influence; and unless he soon become an actual member of the living world, he must expect to be hereafter brought to judgment 'for hiding his light.' the times seem to me to be less dangerous, as to the immediate state of this country, than they were four years ago. the extension of the french empire has weakened the disposable force of france. bonaparte seems to have abandoned the idea of invasion; and if our government is active, we have little to dread from a maritime war, at least for some time. sooner or later, our colonial empire must fall in due time, when it has answered its ends. the wealth of our island must be diminished, but the strength of mind of the people cannot easily pass away; and our literature, our science, our arts, and the dignity of our nature, depend little upon our external relations. when we had fewer colonies than genoa, we had bacons and shakspeares. the wealth and prosperity of the country are only the _comeliness_ of the body--the fulness of the flesh and fat;--but the spirit is independent of them; it requires only muscle, bone, and nerve, for the true exercise of its functions. we cannot lose our liberty, because we cannot cease to _think_; and ten millions of people are not easily annihilated. i am, my dear poole, very truly yours, h. davy. while the electro-chemical laws, developed in the last chapter, are fresh in the recollection of the reader, i shall proceed to the consideration of his second bakerian lecture, which was read in november ; and in which he announces the discovery of the metallic bases of the fixed alkalies,--a discovery immediately arising from the application of voltaic electricity, directed in accordance with those laws;--thus having, as we have seen in the first instance, ascended from particular phenomena to general principles, he now descends from those principles to the discovery of new phenomena: a method of investigation by which he may be said to have applied to his inductions the severest tests of truth, and to have produced a chain of evidence without having a single link deficient. since the account given by newton of his first discoveries in optics, it may be questioned whether so happy and successful an instance of philosophical induction has ever been afforded as that by which davy discovered the composition of the fixed alkalies. had it been true, as was most unjustly insinuated at the time, that the discovery was accidentally effected by the high power of the apparatus placed at his disposal, his claims to our admiration would have assumed a very different character: in such a case, he might be said to have forced open the sanctuary of nature by direct violence, instead of having discovered and touched the secret spring by which its portals were unclosed. the justice of these remarks will best appear in the examination of his memoir: the highest eulogy that can be conferred on its author will be a faithful and plain history of its contents. it will be remembered that, in his preceding lecture of , he had described a number of decompositions and chemical changes produced in substances of known composition, by the powers of electricity, and that in all such cases there invariably subsisted an attraction between oxygen and the _positive_ pole, and between inflammable matter and the _negative_ pole of the pile: thus, in the decomposition of water, its oxygen was transferred to the former, and its hydrogen to the latter. furnished with such data, davy proceeded to submit a fixed alkali to the most intense action of the voltaic apparatus, well convinced that, should the electrical energy be adequate to effect its decomposition, the elements would be transferred, according to this general law, to their respective poles. his first attempts were made on solutions of the alkalies; but, notwithstanding the intensity of the electric action, the water alone underwent decomposition, and oxygen and hydrogen were disengaged with the production of much heat, and violent effervescence. the presence of water thus appearing to prevent the desired decomposition, potash, in a state of igneous fusion, was in various ways submitted to experiment; when it was evident that combustible matter of some kind, burning with a vivid light, was given off at the negative wire. after numerous trials, during the progress of which the difficulties which successively arose were as immediately combated by ingenious manipulation, a small piece of potash sufficiently moistened, by a short exposure to the air, to give its surface a conducting power, was placed on an insulated disc of platina, connected with the negative side of the battery in a state of intense activity, and a platina wire communicating with the positive side, was at the same instant brought into contact within the upper surface of the alkali.--mark what followed!--a series of phenomena, each of which the reader will readily understand as it is announced,--for it will be in strict accordance with the laws which davy had previously established:--the potash began to fuse at both its points of electrization: a violent effervescence commenced at the upper, or positive surface; while at the lower, or negative one, instead of any liberation of elastic matter, which would probably have happened had hydrogen been an element of the alkaline body, small globules, resembling quicksilver, appeared, some of which were no sooner formed than they burnt with explosion and bright flame.--what must have been the sensations of davy at this moment!--he had decomposed potash, and obtained its base in a metallic form. the gaseous matter developed, during the experiment, at the positive pole of the apparatus, he very shortly identified as oxygen. to collect, however, the metallic matter, in a quantity sufficient for a satisfactory examination, was by no means so easy; for, like the _alkahest_ imagined by the alchemist, it acted more or less upon every body to which it was exposed; and such was its attraction for oxygen, that it speedily reverted to the state of alkali by recombining with it. after various trials, however, it was found that recently distilled naphtha presented a medium in which it might be preserved and examined, since a thin transparent film of this fluid, while it defended the metal from the action of the atmosphere, did not oppose any obstacle to the investigation of its physical properties. thus provided, he proceeded to enquire into the nature of the new and singular body, to which he afterwards gave the name of potassium, and which may be described as follows. its external character is that of a white metal, instantly tarnishing by exposure to air; at the temperature of ° fah. it exists in small globules, which possess the metallic lustre, opacity, and general appearance of quicksilver; so that when a globule of the latter is placed near one of the former, the eye cannot discover any difference between them: at this temperature, however, the metal is not perfectly fluid; but when gradually heated, it becomes more so,--and at °, its fluidity is so perfect that several globules may be easily made to run into one. by reducing its temperature, it becomes, at °, a soft and malleable solid, which has the lustre of polished silver, and is soft enough to be moulded like wax. at about the freezing point of water it becomes hard and brittle, and exhibits, when broken, a crystallized structure of perfect whiteness, and of high metallic splendour. it is also a perfect conductor both of electricity and heat. thus far, then, it fulfills every condition of a metal; but an anomaly of a most startling description has now to be mentioned--the absence of a quality which has been as invariably associated with the idea of a metal, as that of lustre, viz. great specific gravity. whence a question has arisen, whether, after all, the alkaline base can with propriety be classed under that denomination? instead of possessing that ponderosity which we should have expected in a body otherwise metallic, it is so light as not only to swim upon the surface of water, but even upon that of naphtha, by far the lightest liquid in nature. davy, however, very justly argues, that low specific gravity does not offer a sufficient reason for degrading this body from the rank of a metal; for amongst those which constitute the class, there are remarkable differences with respect to this quality; that platina is nearly four times as heavy as tellurium. in the philosophical division of bodies into classes, the analogy between the greater number of properties must always be the foundation of arrangement.[ ] [ ] the propriety, and even the necessity, of such a compact become daily more apparent, as our knowledge of bodies extends. if we were to degrade a substance from its class, in consequence of the absence of some one quality which enters into its more perfect examples, we should soon find ourselves involved in paradoxes.--what idea, for instance, could we form of an acid?--its sourness?--prussic acid--arsenious acid, are not sour.--its tendency to combine with an alkaline or earthy base?--if so, sugar is an acid, for it combines with lime. i remember a chemist having been exposed to much ridicule from speaking of a _sweet_ acid--why not? so inseparable however, by long association, are the ideas of ponderosity and metallic splendour, that the evidence even of the senses may fail in disuniting them.[ ] this is well illustrated by the following amusing anecdote. shortly after the discovery of potassium, dr. george pearson happened to enter the laboratory in the royal institution, and upon being shown the new substance, and interrogated as to its nature, he, without the least hesitation, on seeing its lustre, exclaimed, "why, it is metallic, to be sure," and then, balancing it on his finger, he added, in the same tone of confidence, "_bless me, how heavy it is!_" [ ] in the language of darwin, we should say, that the simple ideas of weight and lustre, which form the complex idea of a metal, have become so indissoluble, that they can no longer be separated by volition. the principle admits of many familiar illustrations, and is the source of numerous fallacies. when any one voluntarily recollects a gothic window, which he had seen some time before, the whole front of the cathedral occurs to him at the same time: in like manner, the taste of a pine-apple, though we eat it blindfold, recalls the colour and shape of it. coleridge has made a good remark upon this subject. he says, "it is a great law of the imagination, that a likeness in part tends to become a likeness of the whole." it is thus that we trace images in the fire, castles in the clouds, and spectres in the gloom of twilight. when thrown upon water, potassium instantly decomposes that fluid, and an explosion is produced with a vehement flame: an experiment which is rendered more striking if, for water, ice be substituted; in this latter case, it instantly bums with a bright rose-coloured flame, and a deep hole is made in the ice, which will afterwards be found to contain a solution of potash. it is scarcely necessary to state, that these phenomena depend upon the very powerful affinity which the metal possesses for oxygen, enabling it even to separate it from its most subtle combinations.[ ] [ ] if we are disposed to enter into a more critical examination of the subject, we shall find that, although the above is a general expression of the change produced, there are subordinate actions of a more complicated nature: the metal, in the first place, decomposes a portion of the water, in order to combine with its oxygen, and form potash, which in its turn has a powerful affinity for water; the heat arising from two causes, decomposition and combination, is sufficiently intense to produce the inflammation. water is a bad conductor of heat; the globule swims exposed to air; a part of which is dissolved by the heated nascent hydrogen; and this gas, being capable of spontaneous inflammation, explodes and communicates the effect of combustion to any of the bases that may be yet uncombined. the manner in which the potassium runs along the surface of water may be compared to a drop of water on red-hot iron; in the one case the hot potassium, in the other the cold water, is enveloped in an atmosphere of steam. one of the neatest modes of showing the production of alkali, in the decomposition of water by the basis of potash, consists in dropping a globule of potassium upon moistened paper tinged with turmeric. at the moment that it comes into contact with the water, it burns and moves rapidly upon the paper, as if in search of moisture, leaving behind it a deep reddish-brown trace of its progress, and acting upon the test paper precisely as dry caustic potash. from these observations, the reader will immediately perceive, that the decomposition of the fixed alkalies has placed in the hands of the experimentalist a new instrument of research, scarcely less energetic, or of less universal application, than the power from which the discovery emanated. davy observes upon this point, that "it will undoubtedly prove a powerful agent for analysis, and having an affinity for oxygen, stronger than any other known substance, it may possibly supersede the application of electricity to some of the undecompounded bodies." so strong indeed is its affinity for oxygen, that it discovers and decomposes the small quantities of water contained in alcohol and ether; and in the latter case, this decomposition is connected with an instructive result. potash is insoluble in that fluid: when therefore its base is thrown into it, oxygen is furnished, hydrogen gas disengaged, and the alkali, as it is regenerated, renders the ether white and turbid. but perhaps the most beautiful illustration of its deoxidizing power is afforded by its action on carbonic acid gas, or fixed air: when heated in contact with that gas, it catches fire, and by uniting with its oxygen, becomes potash, while the liberated carbon is deposited in the form of charcoal. as i have already exceeded the limits originally prescribed to myself, i shall not enter into the history of davy's experiments on the other fixed alkali, soda, farther than to state that, when it was submitted to voltaic action, a bright metal was obtained, similar in its general characters to potassium, but possessing sufficiently distinctive peculiarities as to volatility, fusibility, oxidability, &c. to this body davy assigned the name of sodium.[ ] [ ] in his bakerian lecture of , he informs us that he obtains sodium by heating common salt, which has been previously ignited, with potassium--an immediate decomposition takes place, and two parts of potassium produce rather more than one of sodium. in support of the metallic characters of these alkaline bases, it may be necessary to state that they combine with each other, and form alloys; the properties and habitudes of which are very interesting, and are fully described by their discoverer. no sooner had these results been made known to the scientific world, than a question arose, both in this country and abroad, as to the real nature of the bodies which had been thus obtained from the fixed alkalies, and which presented an aspect so obviously metallic. at first, it was conjectured by a few, that they might be compounds of the alkali with the platina used in the experiments; but this was at once disproved by davy having obtained the same results when pieces of copper, silver, gold, plumbago, or even charcoal, had been employed for completing the voltaic circuit. the effect which this and his subsequent discoveries produced, in revolutionizing the theory of chemistry, will form an interesting subject for discussion in a future part of the present work: i shall therefore only remark in passing, that the fact of oxygen, the acknowledged principle of acidity, existing in combination with a metallic base, and imparting to it the properties of an alkali, was no sooner announced, than its truth was strenuously denied. it was an attack upon opinions sanctioned by the general suffrage of the scientific world;--it was, in fact, storming the very citadel of their philosophy: no wonder, then, that the agitator should have been assailed with a full cry for his revolutionary plans.[ ] m. curadau read a paper before the french institute, in which he endeavoured to prove, _first_, that the conversion of the alkalies into metals was not a deoxidation of those bodies, but a combination of them with new elements;--_secondly_, that the affinity of the alkaline metals for oxygen was merely a chemical illusion, occasioned by some body the presence of which had not been suspected;--_thirdly_, that carbon was one of the elements of the alkaline metals, since it could be separated from them at pleasure, or converted into carbonic acid;--and _fourthly_, that if the specific gravities of the new substances were less than that of water, it was because hydrogen was associated with carbon in the combination. [ ] many years afterwards, when davy was travelling on the continent, a distinguished person about a foreign court, enquired who and what he was; never having heard of his scientific fame. upon being told that his discoveries had revolutionized chemistry, the courtier promptly replied--"i hate all revolutionists--his presence will not be acceptable here." it is scarcely necessary to state, that the presence of carbon was readily traced to sources of impurity. the hypothesis which assumed the existence of hydrogen as an element, was not so easily refuted. it was espoused by mm. gay lussac, thénard, and ritter, on the continent, and by mr. dalton in england. the former derived their inference from the action of potassium upon ammonia, by which they obtained a fusible substance that yielded by heat more hydrogen than the ammonia contained; the latter contended that potassium and sodium are proved to be _hydrurets_, by the very process employed for their production; for, since common potash is a _hydrat_, and oxygen is produced at one surface, and potassium at the other, by voltaic action, he conceived that the former arose from the decomposition of water, and that the hydrogen must therefore unite with the potash to form potassium. it is a curious fact, that berthollet, in the very sentence in which he insisted upon the excessive quantity of hydrogen disengaged in his experiment, as a proof that potassium must be a _hydruret_, should have stated that the addition of water to the residuum was necessary for obtaining his result. how could it have happened that he overlooked so obvious a source of hydrogen? mr. dalton, as well as ritter, considered the low specific gravity as favouring the idea of their containing hydrogen; but davy observes that they are less volatile than antimony, arsenic, and tellurium, and much less so than mercury. besides, sodium absorbs much more oxygen than potassium, and, on the hypothesis of hydrogenation, must therefore contain more hydrogen; and yet though soda is said to be lighter than potash, in the proportion of thirteen to seventeen nearly, sodium is heavier than potassium, in the proportion of nine to seven at least. on the theory of davy, this circumstance is what ought to have been expected. potassium has a much stronger affinity for oxygen than sodium, and must condense it much more; and the resulting higher specific gravity of the combination is a necessary consequence. in this manner did davy entangle his opponents in their own arguments, and establish, in the most triumphant manner, the truths of his original views. thus then was a discovery effected, and at once rendered complete, which all the chemists in europe had vainly attempted to accomplish. the alkalies had been tortured by every variety of experiment which ingenuity could suggest, or perseverance perform, but all in vain; nor was the pursuit abandoned until indefatigable effort had wrecked the patience and exhausted every resource of the experimentalist. such was the disheartening, and almost forlorn condition of the philosopher when davy entered the field:--he created new instruments, new powers, and fresh resources; and nature, thus interrogated on a different plan, at once revealed her long cherished secret. in his bakerian lecture, davy observes, that "a historical detail of the progress of the investigation of all the difficulties that occurred, and of the manner in which they were overcome, and of all the manipulations employed, would far exceed the limits assigned to a lecture." but to the chemist, every circumstance, however minute, connected with a subject of such commanding importance, is pregnant with interest; i therefore considered it my duty to search into the archives of the institution, in the hope that i should discover some memoranda which might supply additional information. in examining the laboratory register, i have so far succeeded as to obtain some rough and imperfect notes, which will, to a certain degree, assist us in analysing the intellectual operations by which his mind ultimately arrived at the grand conclusion. it appears from this register that davy commenced his enquiries into the composition of potash on the th, and obtained his great result on the th of october .[ ] his first experiments, however, evidently did not suggest the truth: he does not appear to have suspected the nature of the alkaline base until his last experiment, when the truth flashed upon him in the full blaze of discovery. his first note, dated the th, leads us to infer that he acted on a solid piece of potash, under the surface of alcohol, and several other liquids in which the alkali was not soluble; and that he obtained gaseous matter, which he called at the moment '_alkaligen gas_,' and which he appears to have examined most closely, without arriving at any conclusion as to its nature. on the following day, he, for the first time, would seem to have developed potassium by electric action on potash under oil of turpentine, for the note records the fact of "_the_ globules giving out gas by water, which gas _burnt in contact with air_;" and then follows a query--"does _it_" (the matter of the globules) "not form gaseous compounds with ether, alcohol, and the oils?" here, then, he evidently imagined, that the matter of the globules, which he had never obtained from potash, except when acted upon under oil of turpentine, had formed gaseous compounds with the ether, alcohol, and oils in his previous experiments, and given origin to that which he had termed '_alkaligen gas_.' [ ] on the same day he decomposed soda with somewhat different phenomena. he then leaves the consideration of this gas, and attacks the unknown globules, which probably did not present any metallic appearance under the circumstances in which he saw them, for they must have been as minute as grains of sand. i rather think that he commenced his examination by introducing a globule of mercury, and uniting it with a globule of the unknown substance, for his note says, "action of the substance on mercury,--forms with it a solid amalgam, which soon loses its _alkaligen_ in the air." and from the note which succeeds, he evidently considered this _alkaligen_ (potassium) volatile, as he says "it soon flies off on exposure to the air." october .--it is probable that, in consequence of the property which the unknown substance displayed of amalgamating with mercury, he devised his experiment of the th. he took a small glass tube, about the size and shape of a thimble, into which he fused a platinum wire, and passed it through the closed end. he then put a piece of pure potash into this tube, and fused it into a mass about the wire, so as entirely to defend it from the mercury afterwards to be used. when cold, the potash was solid, but containing moisture enough to give it a conducting power; he then filled the rest of the tube with mercury, and inverted it over the trough: the apparatus being thus arranged, eurêka he made the wire and the mercury alternately positive and negative. and now, conceiving that i have sufficiently explained his brief notes, the reader shall receive the result in his own words: for this purpose i have obtained an engraving of the autograph, which is here annexed; but as it may not be very readily deciphered, i shall first give the substance of it in print.--"when potash was introduced into a tube having a platina wire attached to it--so--and fused into the tube so as to be a conductor, _i. e._ so as to contain just water enough, though solid, and inserted over mercury, when the platina was made negative, no gas was formed, and the mercury became oxydated, and a small quantity of the _alkaligen_ was produced round the platina wire, as was evident from its quick inflammation by the action of water. when the mercury was made the negative, gas was developed in great quantities from the positive wire, and none from the negative mercury, and this gas proved to be pure oxygene--a capital experiment, proving the decomposition of potash." the reviewer of the institution journal well observes that those who knew davy will best conceive the enthusiasm with which this hasty record of his success was dashed off, and will instantly recognise [greek: eurêka] in his "capital experiment." from this same register, it appears that, in the preceding month, he was deeply engaged in experiments on '_antwerp blue_,' which he found to consist of _prussiate of iron_ and _alumina_, "probably in the proportion of two-thirds of the former to one-third of the latter." on the th of october, we learn from the same source, that he performed a beautiful experiment, that of producing the vegetation of the carbon of the wick of a candle, by placing it between the wires of the battery. on the th of the preceding september he addressed a letter to mr. gilbert, which is curious, as it shows that very nearly up to the time of the decomposition of the alkalies, his mind had been engaged on very different subjects. to davies giddy, esq. september , . my dear sir, i inclose mr. carne's paper, which, when you have read, and mr. carne revised, i will thank you to inclose to me, and that as soon as possible, for the completion of the volume. i have been a good deal engaged, since my return, in experiments on distillation, and i have succeeded in effecting what is considered of great importance in colonial commerce, namely, the depriving rum of its empyreumatic part, and converting it into pure spirit. i mention this in confidence, as it is likely to be connected with some profitable results; and it may be beneficial in a public point of view, by lessening the consumption of malt. i have heard of no scientific news; this, indeed, is little the season for active exertion. with best respects to your father, and to mr. and mrs. guillemard, i am, my dear sir, always very faithfully yours, h. davy. few notes have conveyed information of such importance to the scientific world, as that which follows, announcing, at the same time, the decomposition of the fixed alkalies, and the formation of the geological society, of which it would thus appear that davy was one of the founders. to william hasledine pepys, esq. november , . dear pepys, if you and allen had been one person, the council of the royal society would have voted to you the copleian medal;[ ] but it is an indivisible thing, and cannot be given to two. we are forming a little talking geological dinner club, of which i hope you will be a member. i shall propose you to-day. some things have happened in the chemical club, which i think render it a less desirable meeting than usual, and i do not think you would find any gratification in being a member of it. hatchett never comes, and we sometimes meet only two or three. i hope to see you soon. i have decomposed and recomposed the fixed alkalies, and discovered their bases to be two new inflammable substances very like metals; but one of them lighter than ether, and infinitely combustible. so that there are two bodies decomposed, and two new elementary bodies found. most sincerely yours, h. davy. [ ] he alludes to a paper, entitled "on the quantity of carbon in carbonic acid, and on the nature of the diamond; by william allen, esq. f.r.s. and william hasledine pepys, esq." communicated by humphry davy, sec. r.s. m.r.i.a. read june , . in the year , mm. gay lussac and thénard succeeded in decomposing potash by chemical means; for which purpose it is only necessary to heat iron turnings to whiteness in a curved gun-barrel, and then to bring melted potash slowly in contact with the turnings, air being excluded; when the iron, at that high temperature, will take the oxygen from the alkali, and the potassium may be collected in a cool part of the tube. it may likewise be produced by igniting potash with charcoal, as m. curaudau showed in the same year. in the following letter, davy gives an account of his repeating the experiment of mm. gay lussac and thénard; mixing together, as usual, science and angling. to j. g. children, esq. london, july . my dear sir, i have this moment received your kind letter, and i have written to pepys to propose to him to be with you on sunday or monday. i hope for his answer to-morrow morning, and i will write to you immediately. i will procure all the fishing tackle you have proposed, and am most happy to find you in so determined a spirit for piscatory adventure. i have had some letters from france; but nothing new, except an account of the gun-barrel experiment tolerably minute. i have tried it since, and procured potassium, but it was lost from some moisture passing into the aperture of the barrel. all that is necessary for the process is a gun-barrel bent thus, thus, b\______/\_/a.---- b represents the part where the touch-hole is closed; here dry potash is introduced; and the middle, which is to be strongly ignited, contains the filings; the potash is gradually fused and made to run down upon the ignited iron; the potassium collects in a. if you should be able to procure the apparatus for this experiment, i should like to assist in repeating it; and could we procure a large quantity of the basis, we may try its effects, on a great scale, on the undecompounded acids. i will bring some _dry boracic acid_. a copper or platina tube, if you have one, will be proper for trying the experiment in. we may likewise try its action upon the earths, and upon diamond. i have metallized ammonia,[ ] without the application of electricity. when an amalgam of potassium and mercury is brought in contact with an ammoniacal salt, the potassium seizes upon the oxygen, and the hydrogen and nitrogen unite to the quicksilver. i had an opportunity of giving an account, on friday, to the scientific men assembled at greenwich, of your magnificent experiments and apparatus.[ ] sir joseph banks, mr. cavendish, wollaston, &c. all expressed a strong wish that the results should be published. i am most happy you have drawn up the account. i regard the days i have passed in your society, as some of the pleasantest of my life. i look forward with a warm hope to our next meeting. be pleased to assure your father of my highest respect, and of my gratitude for his kindness. i am, my dear sir, very sincerely yours, h. davy. [ ] he here alludes to a train of research, which will be considered hereafter. [ ] this observation relates to the magnificent battery constructed by mr. children, of which he presented an account to the royal society, in a paper read in november , entitled, "an account of some experiments, performed with a view to ascertain the most advantageous method of constructing a voltaic apparatus, for the purpose of chemical research. by john george children, esq. f.r.s." the great battery described in this paper consisted of twenty pairs of plates, each plate being four feet high by two feet wide: the sum of all the surfaces was ninety-two thousand one hundred and sixty square inches, and the quantity of liquid necessary for charging it, one hundred and twenty gallons. at the same time he constructed another battery, which consisted of two hundred pairs of plates, each being only two inches square. in the one case, then, he commanded extent of surface, in the other, extent of number; and by a series of comparative experiments, he fully established the theory of davy (page ), that the _intensity_ of electricity increases with the _number_, and the _quantity_ with the _surface_. it is impossible to reflect upon the chemical processes by which potassium may be obtained, without feeling surprised that the discovery should not have long before been accomplished. it is evident that the substance must have been repeatedly developed during the operations of chemistry; alkalies had been frequently heated to whiteness in contact both with iron and charcoal, and in some instances the appearance of a highly combustible body, which could have been no other than potassium, had even been observed as a result of the process, and yet no suspicion, as to its real nature, ever crossed the mind of the experimentalist; he satisfied himself with designating such a product, whenever it occurred, by the term _pyrophorus_.[ ] i remember the late mr. william gregor informing me that, in the course of his analytical experiments with potash and different metals, he had repeatedly observed a combustion on removing the crucible from the furnace, and exposing its contents, which he could never understand. how admirably do such anecdotes illustrate the remark made in the commencement of the present chapter, that truth may be often touched, but is rarely caught, in the dark! [ ] the pyrophorus of homberg, of which a description is to be found in the _mémoires de l'academie_, for , was made by mixing together any combustible body, as gum, flour, sugar, charcoal, &c. and alum, and then, after roasting the mixture till it was reduced to a dry powder, exposing it in a matrass to a red heat. in this process, the theory of which was first explained by davy, the potash of the alum is converted into potassium, which, by its absorption of oxygen from the atmosphere, generates heat, and sets fire to the charcoal contained in the powder. the facility of the combustion of the bases of the alkalies, and the readiness with which they decomposed water, offered davy the ready means for determining the proportions of their constituent parts: and in comparing all his results, he thinks that it will be a good approximation to the truth, to consider potash as composed of about six parts base and one of oxygen; and soda, as consisting of seven base and two of oxygen. the discovery of potassium led to that of the true nature of what had been long familiar to chemists by the name of _pure potash_, but which ought to have been called the _hydrat_, for the _pure_ alkali was not known until after the discovery of davy. the experiments of mm. gay lussac and thénard have shown this substance to be a _protoxide_. it is difficult of fusion; it has a grey colour and a vitreous fracture, and dissolves in water with much heat. the _peroxide_ is procured by the combustion of potassium at a low temperature; it had been observed by davy in october , but at that time he supposed it to be the oxide containing the smallest proportion of oxygen: it has a yellow colour, and when thrown into water effervesces, and gives out oxygen gas.[ ] when heated very strongly upon platina, oxygen is also expelled from it, and there remains the _protoxide_, or pure potash. [ ] the 'potassa fusa' of our pharmacopoeia generally contains a small proportion of the peroxide, and will therefore effervesce when thrown into water. it was a great object with davy, to show that the product resulting from the combustion of potassium, was a pure oxide free from water; for it is evident that had potassium been a _hydruret_, its combustion must have produced a _hydrat_. this he accomplished by a series of experiments which he performed in the laboratory of mr. children, and which are published in his bakerian lecture of . having discovered the presence of oxygen in the fixed alkalies, he was naturally led by analogy to enquire whether ammonia might not also contain it. it was true that the chemical composition of that body had been considered as satisfactorily settled, and that the conversion of it into hydrogen and nitrogen, in the experiments of scheele, priestley, and berthollet, had left nothing farther to be accomplished. all new facts, however, are necessarily accompanied by a new train of analogies; and davy, in perusing the accounts of the various experiments to which ammonia had been submitted, tells us that he saw no reason for considering the presence of oxygen as impossible; for, supposing hydrogen and nitrogen to exist in combination with oxygen in low proportion, this latter principle might easily disappear in the analytical experiments by heat and electricity, in the form of water deposited upon the vessels employed, or dissolved in the gases produced. under this impression, he commenced a series of experiments by which, he says, he soon became satisfied of the existence of oxygen in the volatile alkali. by means of the voltaic battery, he ignited perfectly dry charcoal in a small quantity of pure ammoniacal gas, and he produced carbonate of ammonia; which could not have happened, had not oxygen been furnished by the volatile alkali to the carbon. in the next place, by an ingenious arrangement of apparatus, he submitted ammonia to a high temperature, and effected its decomposition, when a quantity of water appeared as one of the products. it will be useless to enter into farther details upon this occasion, as we shall presently perceive the subject assumed a different aspect, and led the experimentalist into a new line of enquiry. at the conclusion of his bakerian lecture of , he speaks of the probable composition of the earths, and considers it reasonable to expect that they are compounds of a similar nature to the fixed alkalies--"peculiar highly combustible metallic bases united to oxygen;"--but, as yet, this theory was sanctioned only by strong analogies; it was his good fortune, at a subsequent period, to support it by conclusive facts. when the importance and novelty of the results he obtained from the fixed alkalies, and their influence upon the reigning theories, are duly considered, it may be easily imagined how intense was the curiosity to witness the production of the new metals, to examine their singular qualities, and to question the illustrious discoverer upon their nature and relations. suppose it were publicly announced that one of the greatest astronomers of the day had invented a telescope of new and extraordinary powers; and that by its means a hitherto unsuspected system of heavenly bodies might be seen, the character and motions of which were wholly inconsistent with the newtonian theory of the universe. the surprise and eager curiosity which such an announcement would create might possibly be more general, because a knowledge of astronomy is more widely diffused than that of chemistry; but the sensation would not be more intense than that which the discovery of potassium produced. the laboratory of the institution was crowded with persons of every rank and description; and davy, as may be readily supposed, was kept in a continued state of excitement throughout the day. this circumstance, co-operating with the effects of the fatigue he had previously undergone, produced a most severe fit of illness, which for a time caused an awful pause in his researches, broke the thread of his pursuits, and turned his reflections into different channels. he always laboured under the impression that the fever had been occasioned by contagion, to which he had been exposed in one of the jails during an experiment for fumigating it. this impression appears to have continued through life, for in his "last days" he alludes to it in terms of strong conviction. other persons referred his illness to the deleterious fumes, especially those of baryta, to which his experiments had exposed him: an opinion recorded in an epigram,[ ] which was circulated amongst the members of the institution after his recovery. says davy to baryt, "i've a strong inclination to try to effect your deoxidation;" but baryt replies--"have a care of your mirth, lest i should retaliate, and change _you_ to earth." [ ] i received the above _jeu d'esprit_ from the late learned orientalist, mr. stephen weston, only four days before his death. since its publication in the first edition of this work, a chemical friend sent me the following improved version of it. says davy to baryt, "i feel strong temptation to effect by my art your deoxidation; and the money i've got in my pocket i'll bet all, i prove you a true, though disguised lad of metal." says baryt to davy, "a truce to your mirth; if you turn me to metal, i'll turn you to earth; so moisten your clay, don't improve science daily, nor treat me as you've treated poor soda and kali." upon conversing, however, with dr. babington, who, with dr. frank, attended davy throughout this illness, he assured me that there was not the slightest ground for either of these opinions; that the fever was evidently the effect of fatigue and an over-excited brain. the reader will not feel much hesitation in believing this statement, when he is made acquainted with the habits of davy at this period. his intellectual exertions were of the most injurious kind, and yet, unlike the philosophers of old, he sought not to fortify himself by habits of temperance. should any of my readers propose to me the same question respecting davy, as fontenelle tells us was put to an englishman in paris, by a scientific marquis, with regard to newton,--whether he ate, drank, and slept like other people?--i certainly should be bound to answer in the negative. such was his great celebrity at this period of his career, that persons of the highest rank contended for the honour of his company at dinner, and he did not possess sufficient resolution to resist the gratification thus afforded, although it generally happened that his pursuits in the laboratory were not suspended until the appointed dinner-hour had passed. on his return in the evening, he resumed his chemical labours, and commonly continued them till three or four o'clock in the morning; and yet the servants of the establishment not unfrequently found that he had risen before them. the greatest of all his wants was time, and the expedients by which he economised it often placed him in very ridiculous positions, and gave rise to habits of the most eccentric description: driven to an extremity, he would in his haste put on fresh linen, without removing that which was underneath; and, singular as the fact may appear, he has been known, after the fashion of the grave-digger in hamlet, to wear no less than five shirts, and as many pair of stockings, at the same time. exclamations of surprise very frequently escaped from his friends at the rapid manner in which he increased and declined in corpulence. at the commencement of his severe illness in november , he was immediately attended by dr. babington and dr. frank; and upon its assuming a more serious aspect, these gentlemen were assisted by dr. baillie. such was the alarming state of the patient, that for many weeks his physicians regularly visited him four times in the day, and issued bulletins for the information of the numerous enquirers who anxiously crowded the hall of the institution. his kind and amiable qualities had secured the attachment of all the officers and servants of the establishment, and they eagerly anticipated every want his situation might require. the housekeeper, mrs. greenwood, watched over him with all the care and solicitude of a parent; and, with the exception of a single night, never retired to her bed for the period of eleven weeks. in the latter stage of his illness, he was reduced to the extreme of weakness, and his mind participated in the debility of the body. it may not perhaps be thought philosophical to deduce any inference, as to character, from traits which are displayed under such circumstances: i have little doubt, however, but that the mind, like inorganic matter, will, in its decay, frequently develope important elements, which under other conditions were not distinguishable. suppose pride and timidity to exist as qualities in the same mind, the former might so far predominate as to enable its possessor to face the cannon's mouth; but diminish its force by moral or physical agency, the natural timidity will gain the ascendency, and the hero be converted into a coward. such are my reasons for introducing the following anecdote: i would not give to it a greater value than it deserves, but it surely demonstrates the existence of kindly affections. youthful reminiscences, and circumstances connected with his family and friends, were the only objects which, at this period, occupied his thoughts, and afforded him any pleasure. no swiss peasant ever sighed more deeply for his native mountains, than did davy for the scenes of his early years. he entreated his nurse to convey to his friends his ardent wish to obtain some apples from a particular tree which he had planted when a boy; and, unlike locke with his cherries, he had no power of controlling the desire by his reason, but remained in a state of restlessness and impatience until their arrival: at the same time, he expressed a wish to obtain several other objects, especially an ancient tea-pot, endeared to him by early associations. the following minute appears on the journals of the institution:-- "december , .--mr. davy having been confined to his bed for the last fortnight by a severe illness, the managers are under the painful necessity of giving notice, that the lectures will not commence until the first week in january next." the course was, at the time stated, opened by the reverend mr. (now dr.) dibdin; and his introductory lecture was, by order of the managers, printed "for the satisfaction of those proprietors who were not present." it thus commences:--"before i solicit your attention to the opening of those lectures which i shall have the honour of delivering in the course of the season, permit me to trespass upon it for a few minutes, by stating the peculiar circumstances under which this institution is again opened; and how it comes to pass that it has fallen to me, rather than to a more deserving lecturer, to be the first to address you. "the managers have requested me to impart to you that intelligence, which no one who is alive to the best feelings of human nature can hear without mixed emotions of sorrow and delight. "mr. davy, whose frequent and powerful addresses from this place, supported by his ingenious experiments, have been so long and so well known to you, has for these last five weeks been struggling between life and death;--the effects of those experiments recently made in illustration of his splendid discoveries, added to consequent bodily weakness, brought on a fever so violent as to threaten the extinction of life. over him, it might emphatically be said, in the language of our immortal milton, that ----'death his dart shook, but delayed to strike.' had it pleased providence to have deprived the world of any further benefit from his original talents and immense application, there certainly has been already enough effected by him to entitle his name to a place amongst the brightest scientific luminaries of his country. that this may not appear an unfounded eulogium, i shall proceed, at the particular request of the managers, to give you an outline of the splendid discoveries to which i have just alluded; and i do so with the greater pleasure, as that outline has been drawn in a very masterly manner by a gentleman of all others perhaps the best qualified to do it effectually." the lecturer then proceeded to take a general and rapid view of his labours, which it is unnecessary to introduce in this place, and concluded as follows:-- "this recital will be sufficient to convince those who have heard it of the celebrity which the author of such discoveries has a right to attach to himself; and yet no one, i am confident, has less inclination to challenge it. to us, and to every enlightened englishman, it will be a matter of just congratulation, that the country which has produced the two bacons and boyle, has in these latter days shown itself worthy of its former renown by the labours of cavendish and davy. the illness of the latter, severe as it has been, is now abating, and we may reasonably hope that the period of convalescence is not very remote." fortunately for the cause of science--fortunately for the interests of the institution, the prediction of the learned lecturer was shortly verified. the institution, indeed, had already suffered from the calamity; for, in a report to the visitors, dated january , , it is stated, that "there has been an excess of expenditure beyond the receipts. among the causes of diminished income may be mentioned the postponement of the lectures, in consequence of the lamented illness of the excellent professor of chemistry; and among the items of increased expenditure, the extra expense of the laboratory, in which have been produced mr. davy's recent discoveries, so honourable to the royal institution, and so beneficial to the interests of science in every part of the world." this report is succeeded by the following minute:-- "february , .--mr. davy attended at the request of the committee, and informed them that he should be able to commence his course of lectures on electro-chemical science on saturday the th of march, at two o'clock; and those on geology on wednesday evening, the th of that month." the following letter to mr. poole announces the restoration of his health, and communicates some other circumstances of interest. mr. poole, it would appear, entertained doubts as to whether davy received the prize of france for his first or second bakerian lecture, upon which point this letter sets him right. to thomas poole, esq. march, . my dear poole, many thanks for your kind letter. i have seen your friend mr. b---- for a minute, and, to use a geological term, i like his _aspect_, and shall endeavour to cultivate his acquaintance. i am exceedingly busy; my health is re-established; and i am entering again into the career of experiment. the prize which you congratulate me upon was given for my paper of , and not for my last discoveries, which will probably excite more interest. c----, after disappointing his audience twice from illness, is announced to lecture again this week. he has suffered greatly from excessive sensibility--the disease of genius. his mind is as a wilderness, in which the cedar and the oak, which might aspire to the skies, are stunted in their growth by underwood, thorns, briars, and parasitical plants. with the most exalted genius, enlarged views, sensitive heart, and enlightened mind, he will be the victim of want of order, precision, and regularity. i cannot think of him without experiencing the mingled feelings of admiration, regard, and pity. why do you not come to london? many would be happy to see you; but no one more so than your very sincere friend, my dear poole, h. davy. it is difficult to convey an adequate idea of the universal interest which was excited by the lectures on electro-chemical science, to which an allusion has been just made. the theatre of the institution overflowed; and each succeeding lecture increased the number of candidates for admission. it is unnecessary, after what has been already stated, to describe the masterly style in which he demonstrated and explained those general laws which his genius had developed, or to enumerate the beautiful and diversified experiments by which he illustrated their application, in simplifying the more complex forms of matter. his evening lectures on geology were equally attractive; and by a method as novel as it was beautiful, he exhibited, by the aid of transparencies, the structure of mountains, the stratification of rocks, and the arrangements of mineral veins. the easter recess afforded him a few days of leisure, which from the following note he appears to have devoted to his favourite amusement. to w. h. pepys, esq. april, . my dear pepys, children has had the kindness to arrange our party, and we are to meet him, at all events, on tuesday at two o'clock, at foot's cray. i have proposed that we should leave town at about five or six on monday evening, sleep at foot's cray, and try the fly-fishing there. will you arrange with allen, whom we must initiate in the vocation of the apostles, as he wants nothing else to make him perfect as a primitive christian and a philosopher? i am, my dear pepys, most affectionately yours, h. davy. hitherto his passion for angling has only been noticed in connection with his conversation and letters; i shall now present to the reader a sketch of the philosopher in his fishing costume. his whole suit consisted of green cloth; the coat having sundry pockets for holding the necessary tackle: his boots were made of caoutchouc, and, for the convenience of wading through the water, reached above the knees. his hat, originally intended for a coal-heaver, had been purchased from the manufacturer in its raw state, and dyed green by some pigment of his own composition; it was, moreover, studded with every variety of artificial fly which he could require for his diversion. thus equipped, he thought, from the colour of his dress, that he was more likely to elude the observation of the fish. he looked not like an inhabitant o' the earth, and yet was on't;--nor can i find any object in the regions of invention with which i could justly compare him, except perhaps with one of those grotesque personages who, in the farce of "the critic," attend father thames on the stage, as his two banks. i shall take this opportunity of stating, that his shooting attire was equally whimsical: if, as an angler, he adopted a dress for concealing his person, as a sportsman in woods and plantations, it was his object to devise means for exposing it; for he always entertained a singular dread lest he might be accidentally shot upon these occasions. when upon a visit to mr. dillwyn of swansea, he accompanied his friend on a shooting excursion, in a broad-brimmed hat, the whole of which, with the exception of the brim, was covered with scarlet cloth. notwithstanding, however, the refinements which he displayed in his dress, and the scrupulous attention with which he observed all the minute details of the art; if the truth must be told, he was not more successful than his brother anglers; and here again the temperament of wollaston presented a characteristic contrast to that of davy. the former evinced the same patience and reserve--the same cautious observation and unwearied vigilance in this pursuit, as so eminently distinguished his chemical labours. the temperament of the latter was far too mercurial: the fish never seized the fly with sufficient avidity to fulfill his expectations, or to support that degree of excitement which was essential to his happiness, and he became either listless or angry, and consequently careless and unsuccessful.--but it is time to resume the thread of our chemical history. it has been already stated, that davy had no sooner decomposed the fixed alkalies than he proceeded to effect an analysis of the earths; but his results were indistinct: they could not, like the alkalies, be rendered conductors of electricity by fusion, nor could they be acted upon in solution, in consequence of the strong affinity possessed by their bases for oxygen. the pursuit of the enquiry then demanded more refined and complicated processes, than those which had succeeded with potash and soda. the only methods which held out any fair prospect of success were those of operating by electricity upon the earths in some of their combinations, or of converting them, at the moment of their decomposition, into metallic alloys, so as to obtain presumptive evidence of their nature and properties. such, in fact, was the line of enquiry in which davy was deeply engaged, when he received from professor berzelius of stockholm a letter, announcing the fact that he had, in conjunction with dr. pontin, succeeded in decomposing baryta and lime, by negatively electrising mercury in contact with them, and that, by such means, he had actually obtained amalgams of the earths in question. our philosopher immediately repeated the experiments, and with perfect success. after which he completed a series of additional experiments, which fully established the nature of these bodies, and the analogies he had anticipated. these results formed the subject of a memoir, which was read before the royal society on the th of june , and entitled, "electro-chemical researches on the decomposition of the earths: with observations on the metals obtained from them, and on the amalgam of ammonia." he commences this paper by enumerating the several trials he had made to effect the decomposition of these bodies; such as, first, by electrifying them by iron wires under the surface of naphtha, with a view to form alloys with iron and the metallic bases of the earths. secondly, by heating potassium in contact with the alkaline earths, in the hope that this body might detach the oxygen from them, in the same manner as charcoal decomposes the common metallic oxides. thirdly, by submitting various mixtures of the earths and potash to voltaic action, with the idea that the potash and the earths might be deoxidated at the same time, and entering into combination, form alloys. fourthly, by mixing together various earths with the oxides of tin, iron, lead, silver, and mercury: a mode of manipulation suggested by the results of his previous experiments on potassium, in which he found that when a mixture of potash and the oxides of mercury, tin, or lead, was electrified in the voltaic circuit, the decomposition was very rapid, and an amalgam, or an alloy of potassium, was obtained; the attraction between the common metals and the potassium apparently accelerating the separation of the oxygen. supposing that a similar kind of action might assist the decomposition of the alkaline earths, he proceeded to institute a series of experiments upon that principle; and the results were more satisfactory than those obtained by the preceding methods of experimenting--a compound was obtained which acted upon water with the evolution of hydrogen, producing a solution of the earth, and leaving free the tin, or lead, with which its base may be supposed to have been alloyed;--but in all such experiments the quantity of the metallic basis produced must have been very minute, and its character very questionable. in this stage of the enquiry, davy received the letter from professor berzelius of stockholm, the contents of which he embodied in his memoir, accompanied with such observations as his own information suggested. "a globule of mercury, electrified by the power of a battery consisting of five hundred pairs of double plates of six inches square, weakly charged, was made to act upon a surface of slightly moistened barytes, fixed upon a plate of platina. the mercury gradually became less fluid, and after a few minutes was found covered with a white film of barytes; and when the amalgam was thrown into water, hydrogen was disengaged, the mercury remained free, and a solution of barytes was formed. "the result with lime, as these gentlemen had stated, was precisely analogous. "that the same happy methods must succeed with strontites and magnesia, it was not easy to doubt, and i quickly tried the experiment. from strontites i obtained a very rapid result; but from magnesia, in the first trials, no amalgam could be procured. by continuing the process, however, for a longer time, and keeping the earth continually moist, at last a combination of the bases with mercury was obtained, which slowly produced magnesia, by absorption of oxygen from air, or by the action of water. "all these amalgams i found might be preserved for a considerable period under naphtha. in a length of time, however, they became covered with a white crust under this fluid. when exposed to air, a very few minutes only were required for the oxygenation of the bases of the earths. in the water the amalgam of barytes was most rapidly decomposed; that of strontites, and that of lime next in order: but the amalgam from magnesia, as might have been expected from the weak affinity of the earth for water, very slowly changed: when, however, a little sulphuric acid was added to the water, the evolution of hydrogen, and the production and solution of magnesia, were exceedingly rapid, and the mercury soon remained free." in order, if possible, to procure the amalgams in quantities sufficient for distillation, he combined the methods he had employed in the first instance, with those pursued by berzelius and pontin. "a mixture of the earth with red oxide of mercury was placed on a plate of platina, a cavity was made in the upper part of it to receive a globule of mercury, the whole was covered by a film of naphtha, and the plate was made positive, and the mercury negative, by a proper communication with the battery of five hundred." the amalgams thus procured were afterwards distilled in glass tubes filled with the vapour of naphtha; by which operation the mercury rose pure from the amalgam, and it was very easy to separate a part of it; but the difficulty was to obtain a complete decomposition, for to effect this, a high temperature was required, and at a red heat the bases of the earths instantly acted upon the glass, and became oxidated. in the best result which davy obtained in this manner, the barytic basis appeared as a white metal of the colour of silver, fixed at all common temperatures, but fluid at a heat below redness, and volatile at a heat above it. unlike the alkaline bases, it would seem to be considerably heavier than water. in extending these experiments to alumine, silex, zircone, &c. after a most elaborate investigation, such results were not obtained as justified the conclusion that they were, like the other earths, metallic oxides; although, as far as they went, they added to the probability of such analogy. it will be remembered that, after the fixed alkalies had been found to contain oxygen, davy was very naturally led to enquire whether ammonia might not also contain the same element, or be an oxide with a binary base. in the communication from professor berzelius, and dr. pontin, already alluded to, a most curious experiment is related on what they consider the deoxidation and amalgamation of the compound basis of ammonia; and which they regard as supporting the idea which davy had formed of the presence of oxygen[ ] in the volatile alkali. a fact so startling as the production of a metallic body from ammonia, or from its elements, immediately excited in davy's mind the most ardent desire to pursue the enquiry; and, after repeating the original experiments of the swedish chemists with his accustomed sagacity, he modified his methods of manipulation, in order, if possible, to obtain this metallic body in its most simple form; but, although he succeeded in producing the amalgam without voltaic aid, by the intervention of potassium, he could not so distill off the mercury as to leave the basis, or imaginary _ammonium_, free. [ ] see page . the history of these researches into the nature of the ammoniacal element concludes the lecture of which i have endeavoured to give an outline. the subject of the amalgam is still involved in mystery: if we suppose with davy, that a substance, which forms so perfect an amalgam with mercury, must of necessity be metallic in its own nature, we cannot but conclude either that hydrogen and nitrogen are both metals in the aëriform state, at the usual temperatures of the atmosphere--bodies, for example, of the same character as zinc and quicksilver would be at the heat of ignition--or, that these gases are oxides in their common form, but which become metallized by deoxidation--or, that they are simple bodies, not metallic in their own nature, but capable of composing a metal in their deoxygenated, and an alkali in their oxygenated, state. before we venture, however, to entertain any opinions so extravagant in their nature, and so wholly unsupported by analogy, it would be well to enquire how far the change, which ammonia and mercury undergo by voltaic action, really merits the name of amalgamation. several chemists of the present day are inclined to refer this change of form to a purely mechanical cause, by which the particles of the metal become separated, and converted, as it were, into a kind of _froth_ by the operation.[ ] [ ] the late interesting experiments of mr. daniell "on the action of mercury on different metals," which have been recently published in the first number of a new series of the journal of the royal institution, appear to throw much light upon this subject. by agitating a few grains of spongy platinum with mercury in water acidified with acetic acid, he obtained an amalgam of the consistence of soft butter, which retained its consistence for many weeks, and greatly resembled that formed by the electrization of mercury in contact with ammonia. when the amalgam was laid upon filtering paper, the moisture was gradually absorbed and evaporated, and the mercury returned to a fluid state. by a more refined experiment, mr. daniell ascertained that the process was accompanied by the evolution of hydrogen gas; whence he very fairly concludes, that, when minutely divided, platinum is agitated with mercury, and moisture is present, an electrical action takes place, which, when heightened by the addition of a diluted acid, or the solution of a neutral salt, is sufficiently energetic to decompose water and evolve hydrogen: the oxygen at the same time combines with the mercury, and a solution is effected by the acetic acid, which its unassisted affinity could not have produced. "it also appears," continues mr. daniell, "that this electrical action communicates an adhesive attraction to the particles of the metal, by which the particles of liquid and aëriform bodies are entangled and retained, a kind of _frothy_ compound formed, and the fluidity of the mercury destroyed. the appearance of this amalgam is so very like that of the ammoniacal compound formed by exposing a solution of ammonia in contact with mercury to the influence of the voltaic pile, or when an amalgam of potassium and mercury is placed upon moistened muriate of ammonia, that it is impossible not to be struck with the resemblance. mr. daniell is therefore inclined to believe that the production of the latter may be explained upon the same principles as that of the former. when the effect is produced by the direct application of the electrical current, by means of the battery, it ceases the moment the connexion between the poles is broken; and when brought about by the agency of the amalgam of potassium, the electrical action is doubtless excited by the contact of the two dissimilar metals, and the frothy compound lasts no longer than the existence of the potassium in the metallic state; whereas in the action between mercury and finely divided platinum, the permanence of the metals produces a much more lasting effect, and the soft amalgam may therefore be preserved for a greater length of time. mr. brande, in a late communication in the journal of the royal institution,[ ] observes: "shortly after the discovery of a method of obtaining morphia in a pure state, i remember that sir humphry davy suggested the possibility of its affording, when electrised in contact with mercury, results corresponding with those which berzelius had observed in respect to ammonia. he thought that the nascent elements of the morphia, as liberated by electrical decomposition, might, under such circumstances, effect a similar apparent amalgam of the mercury, and he spoke of the subject as likely to throw some light upon the corresponding ammoniacal combinations. he made, i believe, a few experiments upon the subject; but as the results were not such as he had anticipated, they were not placed on record." [ ] "on the electro-chemical decomposition of the vegeto-alkaline salts." in this communication, the professor gives an account of some experiments of his own, with a view to ascertain whether the vegetable alkalies, if electrised in contact with mercury, would impart any principle to the latter metal. in experiments with morphia and cinchonia, in which the mercury in contact with the vegetable base was rendered negative, not the least change in the fluidity of the metal could be perceived. when, however, a similar experiment was made with quina, the metal became filmy, and acquired even a tendency to a butyraceous appearance, but the phenomenon was found to depend upon the presence of a minute portion of lime. in the progress of our ascent, it is refreshing to pause occasionally, and to cast a glance at the horizon, which widens at every increase of our elevation. by the decomposition of the alkalies and earths, what an immense stride has been made in the investigation of nature!--in sciences kindred to chemistry, the knowledge of the composition of these bodies, and the analogies arising from it, have opened new views, and led to the solution of many problems. in geology, for instance, has it not shown that agents may have operated in the formation of rocks and earths, which had not previously been known to exist? it is evident that the metals of the earths cannot remain at the surface of our globe; but it is probable that they may constitute a part of its interior; and such an assumption would at once offer a plausible theory in explanation of the phenomena of volcanoes, the formation of lavas, and the excitement and effects of subterranean heat, and might even lead to a general theory in geology. the reader, for the present, must be satisfied with these cursory hints: i shall hereafter show that our illustrious philosopher followed them up by numerous observations and original experiments in a volcanic country. i remember with delight the beautiful illustration of his theory, as exhibited in an artificial volcano constructed in the theatre of the royal institution.--a mountain had been modelled in clay, and a quantity of the metallic bases introduced into its interior: on water being poured upon it, the metals were soon thrown into violent action--successive explosions followed--red-hot lava was seen flowing down its sides, from a crater in miniature--mimic lightnings played around: and in the instant of dramatic illusion, the tumultuous applause and continued cheering of the audience might almost have been regarded as the shouts of the alarmed fugitives of herculaneum or pompeii. chapter viii. davy's bakerian lecture of .--results obtained from the mutual action of potassium and ammonia upon each other.--his belief that he had decomposed nitrogen.--he discovers telluretted hydrogen.--whether sulphur, phosphorus, and carbon, may not contain hydrogen.--he decomposes boracic acid.--boron.--his fallacies with regard to the composition of muriatic acid.--a splendid voltaic battery is constructed at the institution by subscription.--davy ascertains the true nature of the muriatic and oxymuriatic acids.--important chemical analogies to which the discovery gave origin.--euchlorine.--chlorides.--he delivers lectures before the dublin society.--he receives the honorary degree of ll.d. from the provost and fellows of trinity college.--he undertakes to ventilate the house of lords.--the regent confers upon him the honour of knighthood.--he delivers his farewell lecture.--engages in a gunpowder manufactory.--his marriage. the third bakerian lecture, which davy read before the royal society in december , is entitled "an account of some new analytical researches on the nature of certain bodies, particularly the alkalies, phosphorus, sulphur, carbonaceous matter, and the acids hitherto undecompounded; with some general observations on chemical theory." the object of this lecture was to communicate the results of numerous experiments which had been instituted for the purpose of still farther extending our knowledge of the elements of matter, by the new powers and methods arising from the application of electricity to chemical analysis. important as were the facts thus obtained, they disappointed the expectation of those who did not consider, that the more nearly we approach ultimate analysis,[ ] the greater must be the difficulties, the more numerous the fallacies, and the less perfect the results, of our processes. in fact, his former discoveries had spoilt us: their splendour had left our organs of perception incapable of receiving just impressions from any minor lights, and we participated with exaggerated feelings, in the disappointment which he himself expressed at several of his results. the confidence inspired by his former triumphs may be compared to that which is felt by an army, when commanded by a victorious general,--a conviction that, however difficult may be the enterprise, it must be accomplished by the genius of him who undertakes it. the moment we discovered that davy was laying siege to one of nature's strongest holds,--that he was attempting to resolve nitrogen into other elementary forms,--we regarded the deed as already accomplished, and the repulse which followed most unreasonably produced a feeling of dissatisfaction. upon such occasions, the severity of our disappointment will always be in proportion to the importance of the object we desire to accomplish; and it is impossible not to feel that the discovery of the true nature of nitrogen would lead to new views in chemistry, the extent of which it is not easy even to imagine. [ ] the difficulty of seizing upon elementary forms, as well as the infinity of combinations of which they are susceptible, are supposed by mr. sankey to be allegorized in the fable of proteus, [greek: prôteios], being derived from [greek: prôtos], signifying the first element. it is not a little singular that mr. leslie, to whom such a speculation was wholly unknown, should have recognised in the same fable a picture of the cautious but intrepid advances of the skilful experimenter: he tries to press nature into a corner,--he endeavours to separate the different principles of action,--he seeks to concentrate the predominant agent, and labours to exclude as much as possible every disturbing influence. notwithstanding the confidence with which modern philosophers have claimed the discovery, the experimental mode of investigation was undoubtedly known and pursued by the ancients, who appear, observes mr. leslie, to have concealed their notions respecting it under the veil of allegory. _proteus_ signified the mutable and changing forms of material objects; and the inquisitive philosopher was counselled by the poets to watch their slippery demon, when slumbering on the shore to bind him, and to compel the reluctant captive to reveal his secrets.--_elements of natural philosophy._ the principal objects of research which this paper embraces are,--the elementary matter of ammonia; the nature of phosphorus, sulphur, charcoal, and the diamond; and the constituents of the boracic, fluoric, and muriatic acids. enquiries which are continued and extended in two successive papers, viz. in one read before the society in february , entitled "new analytical researches on the nature of certain bodies; being an appendix to his bakerian lecture of ;" and in his fourth bakerian lecture of , "on some new electro-chemical researches on various objects, particularly the metallic bodies from the alkalies and earths; and on some combinations of hydrogen." with regard to these admirable papers,--for such they must undoubtedly be considered,--the biographer must confine his observations to their general character and results. they are far too refined to admit of a brief analysis, and too elaborate to allow a successful abridgement. a just idea of their merit can alone be derived from a direct reference to the philosophical transactions. the enquiry commences with experiments on the results produced by the mutual action of potassium and ammonia on each other. his object was twofold: to refute the hypothesis which assumed hydrogen as an element of potassium, and to ascertain the nature of the matter existing in the amalgam of ammonia, or the supposed metallic basis of the volatile alkali: a question intimately connected with the whole of the arrangements of chemistry. as to the former point, it is unnecessary to enter into farther discussion; and with regard to the latter, it is quite impossible to convey an adequate idea of the extent of the enquiry: there does not exist in the annals of chemistry a more striking example of experimental industry. in the course of his experiments on potassium and ammonia, he obtained an olive-coloured body, which he was inclined to regard as a compound of the metallic base of ammonia (_ammonium_) and potassium; and on submitting which to various trials, he uniformly obtained, as the product of its decomposition, a proportion of nitrogen considerably less than that which, upon calculations founded on a rigid analysis of the volatile alkali, ought to have been afforded under such circumstances, while the potassium employed at the same time became oxidated. this result inspired a hope that nitrogen might have been actually decomposed during the process, and that its elements were oxygen and a metallic basis, or oxygen and hydrogen. that he was sanguine in that hope, appears from the whole tenor of his paper; in farther proof of which, i can adduce a letter which he addressed to mr. children during the progress of his experiments, in which he says, "i hope on thursday to show you nitrogen as a complete wreck, torn to pieces in different ways." his subsequent enquiries, however, although they did not strengthen the suspicion he had formed respecting the decomposition of that body, yet indirectly developed facts of considerable importance; which, with his characteristic quickness of perception, he made subservient to fresh investigation. his researches into the phenomena exhibited by tellurium, when forming a part of the voltaic circuit, are highly interesting. it had been stated by ritter, that, of all the metallic substances he tried for producing potassium by negative electricity, tellurium was the only one by which he could not procure it; and he uses this fact in support of his opinion, that potassium is a _hydruret_. he says, that when a circuit of electricity is completed in water by means of two surfaces of tellurium, oxygen is given off at the positive surface, and instead of hydrogen at the negative surface, a brown powder is formed and separated, which he regards as a _hydruret_ of tellurium; and he conceives that the reason why that metal prevents the metallization of potash is, that it has a stronger attraction for hydrogen than that possessed by the alkali. davy's attention was naturally arrested by such a statement, and, in pursuing the enquiry, he discovered a series of new facts:--he found that tellurium and hydrogen were capable of combining, and of forming a gas, to which he gave the name of _telluretted hydrogen_,--that, so far from tellurium preventing the decomposition of potash, it formed an alloy with potassium when negatively electrified upon the alkali--and, such was the intense affinity of potassium and tellurium for each other, that the decomposition of potash might be effected by acting on the oxide of the latter metal and the alkali, at the same time, by heated charcoal. with respect to the next subject of enquiry in these papers, _viz._ whether sulphur, phosphorus, and carbon, in their ordinary forms, may not contain hydrogen, it would appear that from an experiment performed by mr. clayfield, and which davy witnessed at bristol in the year , he was very early led to suspect the existence of hydrogen in sulphur; but it was not until , that he entered upon the investigation of the subject. from the general tenor of his experiments he concluded that, in its common state, it may be regarded as a compound, of small quantities of oxygen and hydrogen, with a large quantity of a basis which, on account of its strong attractions for other bodies, has not hitherto been obtained in its pure form. the same analogies apply to phosphorus and carbon. his conclusion was mainly derived from the fact, that hydrogen is produced from sulphur and phosphorus in such quantities by voltaic electricity, that he thinks it cannot well be considered as an accidental ingredient in them: the presence of oxygen, he contends, may be inferred from the circumstance that, when potassium is made to act upon these bodies, the sulphurets and phosphurets so formed evolve by the action of an acid less hydrogen, in the form of compound inflammable gas, than the same quantity of potassium in an uncombined state. the question, however, still remains in considerable doubt; and in his "elements of chemical philosophy," published four years afterwards, he admits that no accurate conclusions have been formed on the subject. in his second bakerian lecture of , davy had given an account of an experiment in which boracic acid appeared to be decomposed by voltaic electricity, a dark-coloured inflammable substance separating from it on the negative surface. in the memoir now under consideration, he procured the basis by heating together boracic acid and potassium, when he ascertained it to be a peculiar inflammable matter, which, after various experiments upon its nature, he was inclined to regard as metallic; on which account he proposed for it the name of _boracium_. at about the same period, mm. gay lussac and thénard were engaged in investigating the same subject in france, and they anticipated him in some of the results. when davy, by subsequent experiments, had ascertained that the base of the boracic acid is more analogous to carbon than to any other substance, he adopted the term _boron_, as less exceptionable than that of _boracium_. at this time, he also entered upon the investigation of fluoric acid, the results of which must be reserved for future consideration. his experiments and reasonings upon muriatic acid, at this period of his career, must be now considered as deriving their greatest degree of interest from their fallacy; and they deserve an examination in this work, if it be only to estimate the vigour he subsequently displayed in disentangling himself from a web of his own fabrication. the most satisfactory proof of intellectual strength is to be found in the existence of a power which enables the mind to conquer its prejudices and to correct its own errors. how many remarkable instances does the history of science present, in which the philosopher has treated his facts as procrustes did his victims, in order that they might accord with the measure most convenient for his purpose! prejudiced by the general opinion respecting the hitherto undecompounded nature of muriatic acid, he had long sought to discover its radical by the agency of voltaic electricity; but he uniformly found that when its aqueous solution was thus acted upon, the water alone underwent decomposition; while the electrization of the gas afforded no other indication of its nature than the presence of a much greater quantity of water than theory had assigned to it. he proceeded, therefore, to examine the acid by other modes of enquiry: he found, by the action of potassium upon the gas, that a large volume of hydrogen was evolved, which, in conjunction with other experiments, satisfied him that this body, in its common aëriform state, contained at least one-third of its weight of water; and he adopted various expedients with the hopes of obtaining the acid free from it. without pursuing him through this research, i shall merely state the conclusions at which he arrived, _viz._ that dry muriatic acid, could it be obtained, would probably be found to possess the strongest and most extensive powers of combination of all known substances belonging to the class of acids; and that its basis, should it ever be separated in a pure form, will be one of the most powerful agents in chemistry. from the fact of water appearing in a separate state, and oxymuriatic acid being formed whenever a metallic oxide was heated in muriatic acid gas, he was led to consider the muriatic acid as a compound of a certain base, (not hitherto obtained in a separate state,) and not less than one-third part of water; while he regarded oxymuriatic acid as a compound of the same base (free from water) with oxygen. after the numerous experiments in which the original battery of the institution had been used, so greatly were its metallic plates corroded, that it was found to be no longer serviceable; in consequence of which, as it would appear from a minute, dated july , , "mr. davy laid before the managers of the royal institution the following paper, _viz._ "a new path of discovery having been opened in the agencies of the electrical battery of volta, which promises to lead to the greatest improvements in chemistry and natural philosophy, and the useful arts connected with them; and since the increase of the size of the apparatus is absolutely necessary for pursuing it to its full extent, it is proposed to raise a fund by subscription, for constructing a powerful battery, worthy of a national establishment, and capable of promoting the great objects of science. "already, in other countries, public and ample means have been provided for pursuing these investigations. they have had their origin in this country; and it would be dishonourable to a nation so great, so powerful, and so rich, if, from the want of pecuniary resources, they should be completed abroad. "an appeal to enlightened individuals on this subject can scarcely be made in vain. it is proposed that the instrument and apparatus be erected in the laboratory of the royal institution, where it shall be employed in the advancement of this new department of science." the minute goes on then to state that-- "the above paper having been laid before the board of managers, they felt it their indispensable duty instantly to communicate the same to every member of the royal institution, lest the slightest delay might furnish an opportunity to other countries for accomplishing this great work, which originated in the brilliant discoveries recently made at the royal institution. "the managers present agree to subscribe to this undertaking. "ordered, that a book be opened at the steward's office for the purpose of entering the names of all those members who may wish to contribute towards this important national object." to the great gratification of davy, and to the honour of the country, the list of subscribers was soon completed, and one of the most magnificent batteries ever constructed was speedily in full operation. it is thus alluded to in his elements of chemical philosophy:--"the most powerful combination that exists, in which number of alternations is combined with extent of surface, is that constructed by the subscriptions of a few zealous cultivators and patrons of science, in the laboratory of the royal institution. it consists of two hundred instruments connected together in regular order, each composed of ten double plates arranged in cells of porcelain, and containing in each plate thirty-two square inches; so that the whole number of double plates is two thousand, and the whole surface one hundred and twenty-eight thousand square inches." this battery, when the cells were filled with sixty parts of water mixed with one part of nitric acid, afforded a series of brilliant and impressive effects. when pieces of charcoal, about an inch long, and one-sixth of an inch in diameter, were brought near each other, (within the thirtieth or fortieth parts of an inch,) a bright spark was produced, and more than half the volume of the charcoal became ignited to whiteness, and by withdrawing the points from each other a constant discharge took place through the heated air, in a space equal at least to four inches, producing a most brilliant ascending arch of light, broad and conical in form in the middle. when any substance was introduced into this arch, it instantly became ignited; platina melted as readily in it as wax in the flame of a common candle; quartz, the sapphire, magnesia, lime, all entered into fusion; fragments of diamond, and points of charcoal and plumbago rapidly disappeared, and seemed to evaporate in it, even when the connexion was made in a receiver exhausted by the air-pump; but there was no evidence of their having previously undergone fusion. all the phenomena of chemical decomposition were produced with intense rapidity by this combination. when the points of charcoal were brought near each other in non-conducting fluids, such as oils, ether, and oxymuriatic compounds, brilliant sparks occurred, and elastic matter was rapidly generated. among the numerous experiments performed by the aid of this battery, he instituted several, in the hope of decomposing nitrogen; and which are recorded in his bakerian lecture of . he ignited potassium, by intense voltaic electricity, in this gas; and the result was, that hydrogen appeared, and some nitrogen was found deficient. this, on first view, led him to the suspicion that he had attained his object; but, in subsequent experiments, in proportion as the potassium was more free from a coating of potash, which necessarily introduced water, so in proportion was less hydrogen evolved, and less nitrogen found deficient. the general tenor of these enquiries, therefore, did not strengthen the opinion he had formed with respect to the compound nature of nitrogen. it appears from the following letter, that davy visited his friend mr. andrew knight at downton, in september . it is introduced in these memoirs principally for the purpose of showing with what boldness he was accustomed to depart from generally received opinions, and to project new theories for the explanation of the most abstruse subjects. to john george children, esq. september , . my dear friend, i am about to visit downton, and shall return by the first of october. i have neither seen nor heard from lord darnley, and i conjecture he has not yet returned from scotland. i wish you great sport in pheasant-shooting, but i trust you have had still nobler game in your laboratory. i doubt not you have found before this, as i have done, that the substance we mistook for _sulphuretted_ hydrogen is _telluretted_ hydrogen, very soluble in water, combinable with alkalies and earths, and a substance affording another proof that hydrogen is an oxide. i have met with another analogous compound, that of _boracium_ with hydrogen, which possesses very similar properties. i find that taking _ammonium_ as the basis of hydrogen, according to the ideas which i stated, all the compounds will agree with the suppositions that i mentioned to you, _viz._ eight cubic inches of hydrogen, two of oxygen, ammonia; four and two, water; four and four, nitrogen; four and six, nitrous oxide; four and eight, nitrous gas; four and ten, nitric acid. where the multiples are not in geometrical order, the decomposition is most easy, _i.e._ in nitrous oxide and nitric acid; more easy in water than in ammonia; but most difficult in nitrogen, where there is probably the most perfect equilibrium of affinities. i have kept charcoal white hot by the voltaic apparatus, in dry oxymuriatic acid gas for an hour, without effecting its decomposition. this agrees with what i had before observed with a red heat. it is as difficult to decompose as nitrogen, except when all its elements can be made to enter into new combinations. i find the radiation, _in vacuo_, from ignited platina, is to that in air as three to one:--so much for leslie's hypothesis. a little electrical machine acts with a repulsion as two, in a vacuum equal to five inches of mercury; as thirty, in common air; as thirty, in oxygen; as twenty-nine or thirty, in hydrogen; and as forty-five, in carbonic acid. i showed this experiment, made with every precaution, to mr. cavendish, dr. herschell, dr. wollaston, and warburton: so much for the theory, that electricity is dependent upon oxidation. i do not think our worthy friend pepys will resist any longer. pray let me know what you have been doing. i hope you will not suffer these beautiful and satisfactory experiments of the capacities of metals to remain still. write me a letter as egotistical as the one i have given you. you are pledged to do good and noble things, and you must not disappoint the men of science of this country. with kindest remembrances to your excellent father, and with hopes that we shall soon meet, i am, my dear friend, very faithfully and affectionately yours, h. davy. the genius displayed by mr. knight in investigating the phenomena of vegetable nature, and in applying the knowledge thus acquired to objects of practical improvement, excited in davy, as might have been expected, feelings of the highest admiration; and when, in addition to such claims, he was the acknowledged patron and hospitable friend of the angler, the reader will readily imagine the warmth of feeling with which our philosopher cherished his friendship. on commencing the present work, i applied to mr. knight for any assistance he might be able to afford me, in aid of so arduous a labour; and he very kindly returned an answer, from which i extract the following passage. "my late lamented friend, sir humphry davy, usually paid me a visit in the autumn, when he chiefly amused himself with angling for grayling, a fish which he appeared to take great pleasure in catching. he seemed to enjoy the repose and comparative solitude of this place, where he met but few persons, except those of my own family, for we usually saw but little company. he always assured me that he passed his visits agreeably, and i had reason to believe he expressed his real feelings. "in the familiar conversations of these friendly visits, he always appeared to me to be a much more extraordinary being than even his writings, and vast discoveries, would have led me to suppose him; and, in the extent of intellectual powers, i shall ever think that he lived and died without an equal." the reader has already been made acquainted with those experiments which led davy to modify the prevailing opinions, with regard to the constitution of the muriatic and oxymuriatic acids; and on the false assumption that oxygen existed in the latter gas, to refer the deposition of water which takes place upon heating a metallic oxide in the former, to the supposition that muriatic acid contains a large proportion of water as essential to its composition. upon observing, however, that charcoal, if freed from hydrogen and moisture, even when ignited to whiteness in oxymuriatic, or muriatic acid gas, by the voltaic battery, did not effect the least change in them, he was led to suspect the accuracy of his previous conclusion; and on retracing his steps, and entering upon a new path of enquiry, he ultimately succeeded, after one of the most acute controversies that ever sprang from a chemical question, in recalling philosophers to the original theory of scheele, by establishing the important truth, that oxymuriatic acid is, in the true logic of chemistry, a simple body, which becomes muriatic acid by its union with hydrogen. the new views arising out of such a revolution in chemical opinion are certainly not the least important of those to which the discoveries of davy have given birth. dr. johnson has remarked, that "one of the most hazardous attempts of criticism is to choose the best amongst many good." i am much mistaken, however, if the chemists of europe will not, without hesitation, pronounce his researches into the nature of oxymuriatic acid, and its relations, with the exception of those by which he established the chemical laws of voltaic action, to be by far the most important of all his labours; not only as evincing the ascendancy of his genius, and the steadiness of his perseverance, but as marking a new and splendid era in chemical science. it is much more difficult to eradicate an ancient error than to establish a new truth; and on this occasion, he had not only to contend against the pampered errors of a domineering system, but against the equivocal and illusive evidence, or, if i may be allowed the expression, the apparent neutrality of facts by which the truth of his theory was to be judged. in consequence of the constant and often unsuspected interference of water, there is scarcely a result connected with the chemical history of the bodies in dispute, that did not admit of being equally well explained upon the hypothesis that oxymuriatic acid is a compound, as upon that of its being a simple or undecompounded substance. the question could never have been determined but by an investigation of the most refined and subtile nature; so delicately was the evidence balanced, that nothing but the keenest eye, and the steadiest hand, could have determined the side on which the beam preponderated. the illustrious discoverer of oxymuriatic acid considered that body as muriatic acid freed from hydrogen, or, in the obscure language of the stahlian school, as muriatic acid deprived of phlogiston, whence he assigned to it the name of _dephlogisticated_ muriatic acid. upon the establishment of the antiphlogistic theory by lavoisier, it became essential to the generalization which distinguished it, that a body performing the functions of an acid, and above all, supporting the process of combustion, should be regarded as containing oxygen in its composition; and facts were not wanting to sanction such an inference. the substance could not even be produced from muriatic acid, without the action of some body known to contain oxygen; while the fact of such a body becoming deoxidated by the process, seemed to demonstrate, beyond the possibility of error, that the conversion of the muriatic into the oxymuriatic acid, was nothing more than a simple transference of oxygen from the oxide to the acid: an opinion which was universally adopted, and which for nearly thirty years triumphed without opposition. the body of evidence by which davy overthrew this doctrine, and established the undecompounded nature of oxymuriatic acid, is to be found in a succession of papers read before the royal society, _viz._ in that already announced,--in his bakerian lecture for ,--and in a subsequent memoir read in february . it will be impossible for me to follow the author through all the intricacies of the enquiry; but i shall seize upon some of its more prominent points, and give a general outline of its bearings. no sooner had his suspicions been excited with regard to the compound nature of oxymuriatic acid, than it occurred to him that, if oxygen were really present in that body, he might readily obtain it from some of its compounds; that, for instance, its combination with tin would yield an oxide of that metal by ammonia; while those with phosphorus would furnish, on analysis, either the phosphor_ous_, or phosphor_ic_ acid. but after experiments in which the presence of water was most cautiously excluded, the results he had anticipated were not obtained. in the place of an oxide of tin, the product, on the application of heat, volatilized in dense and pungent fumes; and, instead of obtaining an acid of phosphorus, a body possessing new and unexpected properties resulted. again,--it had been stated, in confirmation of the theory that recognised the presence of oxygen in oxymuriatic acid, that when this latter body and ammonia were made to act upon each other, water was formed: our chemist frequently repeated the experiment, and convinced himself that such was not the fact. it had been shown by mr. cruickshank, and more recently proved by mm. gay lussac and thénard, that oxymuriatic acid and hydrogen, when mixed in nearly equal proportions, produce a matter almost entirely condensable by water, which is common muriatic acid; and that water is not deposited in the operation. davy made many experiments on the subject, and he found, that when these gases were mingled together in equal volumes over water, introduced into an exhausted vessel, and fired by the electric spark, muriatic acid resulted, although, at the same time, there was a certain degree of condensation, and a slight deposition of vapour; but on repeating the experiment in a manner still more refined, and by carefully drying the gases, such condensation became proportionally less. when, in addition to the above experimental evidence, it is stated that mm. gay lussac and thénard had proved, by a copious collection of instances, that in the usual cases where oxygen is eliminated from oxymuriatic acid, water is always present, and muriatic acid gas is formed; and as it has been moreover shown that oxymuriatic is converted into muriatic acid gas by combining with hydrogen, it is scarcely possible to avoid the conclusion, that the oxygen is derived from the decomposition of water, and not from that of the acid. when mercury is made to act, by means of voltaic electricity, upon one volume of muriatic acid gas, all the acid disappears, calomel is formed, and half a volume of hydrogen is evolved. by such experiments and arguments, davy was led to the conclusion that, as yet, oxymuriatic acid has not been decompounded; that it is a peculiar body, elementary as far as our knowledge extends, and analogous, in its tendency of combination with inflammable matter, to oxygen gas; that, in fact, it may be a _peculiar_ acidifying and dissolving principle, forming with different substances compounds analogous to acids containing oxygen, or to oxides, in their properties and powers of combination, but differing from them in being, for the most part, decomposable by water. on this idea, he thinks that muriatic acid may be considered as having hydrogen for its base, and oxymuriatic acid for its acidifying principle. in confirmation of such an opinion, it is also important to remark, that in its electrical relations, oxymuriatic acid maintains its analogy to oxygen. the vivid combustion of bodies in oxymuriatic acid gas, davy acknowledges, may, at first view, appear a reason why oxygen should be admitted as one of its elements; but he answers this argument by stating, that heat and light are merely results of the intense agency of combination; and that sulphur and metals, alkaline earths and acids, become alike ignited under such circumstances. as change of theory with regard to the primitive must necessarily modify all our views with respect to the nature of secondary bodies, so must this new view of oxymuriatic acid affect all our opinions respecting its compounds. davy accordingly proceeded, in the first place, to investigate the various bodies which had been distinguished by the name of _hyper-oxymuriates_, _muriates_, &c. it also became necessary to alter the nomenclature, since to call a body which neither contains oxygen nor muriatic acid, by a term which denotes the presence of both, is contrary to those very principles which first suggested it. having consulted some of the most eminent philosophers, davy proposed a name founded upon one of the most obvious and characteristic properties of the oxymuriatic acid, namely, its colour, and called it chlorine. if then oxymuriatic acid, or chlorine, does not contain any oxygen, a question immediately arises as to the true nature of those compounds in which the muriatic acid has been supposed to exist in combination with a much larger proportion of oxygen than in the oxymuriatic acid,--in the state in which it has been named by mr. chenevix _hyper-oxygenized_ muriatic acid. in his bakerian lecture of , entitled, "on some of the combinations of oxymuriatic gas and oxygen, and on the chemical relations of these principles," he details a number of experiments for the illustration of this subject, and arrives at the conclusion, that the oxygen in the hyper-oxymuriate of potash is in triple combination with the metal and chlorine. he likewise confirms his views, with regard to the elementary nature of this latter body, by a series of new enquiries, and shows that they are not incompatible with known phenomena:--for instance, scheele explained the bleaching powers of oxymuriatic gas, by supposing that it destroyed colours by combining with _phlogiston_. berthollet[ ] considered it as acting by imparting oxygen; davy now proves that the pure gas is wholly incapable of altering vegetable colours, and that its operation in bleaching entirely depends upon its property of decomposing water, and of thus liberating its oxygen.[ ] the experiment by which he demonstrated this fact is so simple and satisfactory, that i shall here relate it. having filled a glass globe, containing dry powdered muriate of lime, with oxymuriatic gas, he introduced into another globe, also containing muriate of lime, some dry paper tinged with litmus, that had been just heated; by which device the intrusion of moisture was effectually prevented. after some time, this latter globe was exhausted, and then connected with that containing the oxymuriatic gas, and by an appropriate set of stop-cocks, the paper was exposed to the action of the gas thus dried: no change of colour in the test paper took place, and after two days, there was scarcely a perceptible alteration; while some similar paper dried and introduced into the gas, that had not been exposed to muriate of lime, was instantly bleached. [ ] berthollet first applied oxymuriatic acid for the purpose of bleaching, in france; from whence mr. watt introduced it into england. [ ] dr. thomson has more recently explained the operation, by supposing that water is decomposed, and that its hydrogen goes to the chlorine, and its oxygen to the water, forming with the latter a deutoxide of hydrogen, or the oxygenated water of thénard, which he considers as the true bleaching principle. as an illustration of the eagerness with which he seized upon facts, in order to apply them to economical purposes, it may be stated that, on reflecting upon the theory of bleaching, and on the changes which its agents undergo, he was led to propose the use of a liquor produced by the condensation of oxymuriatic gas in water, containing magnesia diffused through it, as superior to the oxymuriate of lime commonly employed.[ ] [ ] experience has not confirmed the value of this suggestion. davy imagined that the vegetable fibre was injured by the saline residuum; and having found that muriate of magnesia was less corrosive than muriate of lime, he was led to propose the substitute above stated. the fact, however, is, that the fibre is injured by the chlorine; and as this body has only a slight affinity for magnesia, it too quickly abandons it; and consequently the oxymuriate of lime is still preferred. it has been very truly observed, that all knowledge which is gained tends towards the acquisition of more, just as the iron dug from the mine facilitates in return the working of the miner. never was this truth more forcibly illustrated than by the discovery of the nature of chlorine. in the progress of that train of enquiry, which became necessary for the adjustment of our views as they regarded the combinations of that body, davy discovered a series of new compounds, the history of which he communicated in successive papers to the royal society. in a memoir read in february , entitled, "on a combination of oxymuriatic gas and oxygen gas," he announced the existence of a _protoxide_ of chlorine, under the name of _euchlorine_; and in a communication from rome in the year , he described another compound of chlorine and oxygen, containing a still larger proportion of this latter element, and which has since been made the subject of a series of experiments by count stadion of vienna. as it does not exhibit any acid properties, dr. henry proposes to call it a _peroxide_, in preference to _deutoxide_; thinking it probable that intermediate compounds, between this and the protoxide already mentioned, may be hereafter discovered. his paper on _euchlorine_ abounds with interest. he found that by acting on the salts formerly denominated _hyper-oxymuriates_, by muriatic acid, the gas evolved differed very greatly in its properties, with the different modes of preparing it. when much acid was employed with a small quantity of the salt, and the gas was collected over water, it was not found to differ from oxymuriatic gas; but when, on the other hand, the gas was procured by means of a weak acid, and a considerable excess of the salt, at a low heat, and was collected over mercury, it possessed properties essentially different. its colour, under such circumstances, was of a dense tint of brilliant yellow-green, whence the name of _euchlorine_.[ ] when in a pure form, this gas is so readily decomposed, that it will sometimes explode during the time of its transfer from one vessel to another, producing both heat and light with an expansion of volume,[ ] and it may always be made to explode by a very gentle heat, often even by that of the hand. [ ] from [greek: eu] and [greek: chlôros]. [ ] the most vivid effects of combustion known are those produced by the _condensation_ of oxygen, or chlorine: but in this instance, a violent explosion with heat and light is produced by their separation, and _expansion_; a perfectly novel circumstance in chemical philosophy. the results of its explosion indicate its composition to be one atom of chlorine, and one of oxygen. none of the metals that burn in chlorine act upon this gas at common temperatures; but when the oxygen is separated, they then inflame in the residual chlorine. this fact davy illustrated by a series of experiments, one of which, from its extreme beauty, i shall here relate. if a glass vessel, containing copper-leaf, be exhausted, and the euchlorine afterwards admitted, no action will take place; but throw in a little nitrous gas, and a rapid decomposition will ensue, and the metal will burn with its accustomed brilliancy. the discovery of this interesting gas, and that of the facts connected with it, not only confirmed the novel views with regard to the elementary nature of chlorine, but they reconciled the contradictory accounts of different authors respecting the properties of that body. the weak attraction subsisting between the elements of this compound gas, which by a comparatively low temperature are made repulsive of each other, confirms also the supposition of davy, that oxygen and chlorine belong to the same class of bodies. the discovery of the _peroxide of chlorine_ was made during an examination of the action of acids on the _hyper-oxymuriates_ of chenevix, undertaken by davy in consequence of a statement of m. gay lussac, that a peculiar acid, which he called _chloric acid_, might be procured from the _hyper-oxymuriate of baryta_ by sulphuric acid. with regard to this acid, which its discoverer considered as composed of one atom of chlorine and five atoms of oxygen, davy entered into a warm controversy, affirming that the fluid in question owed its acid powers to combined hydrogen; and that it was analogous to the other hyper-oxymuriates, as being triple compounds of inflammable bases with chlorine and oxygen, in which the two former determine the character of the compound: this opinion, however, he afterwards abandoned, and i have reason to believe that he regretted ever having advanced it. amidst these new views, it became necessary to alter our opinions with regard to many of those compounds which have been termed _muriates_, but which, it would appear, contain neither muriatic acid nor oxygen, but are, strictly speaking, combinations of metals with chlorine, held in union by a very powerful affinity, since chlorine is capable of expelling the whole of the oxygen from any metallic oxide, and of taking its place; even those metals that are most distinguished by their affinity for oxygen, abandon it whenever their oxides are heated in chlorine, in which case oxygen gas is disengaged. the same metal is also capable of uniting with different proportions of chlorine, which, so far as has been yet ascertained, are definite, and in no case exceed two proportions to one of metal. hence it was proposed by davy, in fixing the nomenclature of these compounds, to designate such as contain the least proportion of chlorine by the termination _ane_, added to the latin name of the metal, as _cuprane_ for that of copper; those containing the larger proportion of chlorine, by the termination _anea_, as _cupranea_. the chemical name of our common culinary salt, in conformity with such a nomenclature, would be _sodane_. this proposition, however, has not been adopted;[ ] the compounds of metals and chlorine are either called _chlorurets_, or what is preferable, from their analogy with the similar compounds of oxygen, _chlorides_, and which are further distinguished as _protochlorides_, _deutochlorides_, &c. [ ] a little reflection will convince us that such a nomenclature could never have been adopted with propriety. it is in direct defiance of the linnæan precept, that a specific name must not be united to the generic as a termination; besides which, such terms could never have been preserved in translations into other languages. in connexion with the history of these chlorides, a question arises of great interest and obscurity, and which has engaged the attention of some of our most distinguished chemists,--whether such a body, when dissolved by water, remains as a chloride; or, by decomposing that fluid, and combining with its elements, is not immediately converted into a muriate? with respect to several of these chlorides, no doubt can be entertained as to the fact of their decomposing water; for instance, the chloride of phosphorus is thus acted upon, the oxygen of the water forms phosphorous acid with the phosphorus, while its hydrogen unites with the chlorine to form muriatic acid; and as those products are such as do not combine with each other, but exist in a state of mixture in the water, each may be recognised by its peculiar properties. in like manner, as davy has observed, when water is added in certain quantities to libavius's liquor (_deutochloride of tin_), a solid crystalline mass is obtained, from which oxide of tin and muriate of ammonia can be obtained by ammonia. in his elements of chemical philosophy, davy has been, in many instances, explicit on this point; and his opinions are favourable to the idea that chlorides become muriates by being dissolved in water: thus, he states that the perchloride of iron "acts with violence upon water, and forms a solution of red muriate of iron;" and he observes that the permuriate "forms a solution of green muriate of iron by its action upon water."[ ] with regard, however, to the general principle, that chlorides become muriates by solution, there are difficulties which do not fall within the province of a biographer to discuss. i shall merely observe that such a change is, in many cases, so inconsistent with our preconceived opinions, that very strong evidence is required to reconcile us to its truth. we are undoubtedly prepared to hear that much may happen between the cup and the lip,--but that common salt should be a _chloride of sodium_ on our plates, and a _muriate of soda_ in our mouths, is certainly a very startling assertion. [ ] for an admirable paper upon this subject by mr. r. phillips, in which all the material points of the subject are considered with that acumen which distinguishes its author, see annals of philosophy, vol. i. new series. the reception which the chloridic theory met with from the chemical world might aptly enough be adduced in illustration of that remark with which i commenced the preceding chapter. at first, its truth was questioned, and no sooner had this been triumphantly established, than an attempt was invidiously made to transfer the glory of the discovery from davy to the french philosophers. upon each of these points, i shall beg to offer a few observations. first, with regard to the fact of chlorine being as yet an undecompounded body. the very announcement of a theory so adverse to the universal faith of europe, was a signal for open hostilities; the observations of dr. murray may be considered as expressing the sentiments of most of the leading chemists on the first publication of the novel views of davy. "opinions," says he, "more unexpected have seldom been announced to chemists, than those lately advanced by mr. davy with regard to the constitution of the muriatic and oxymuriatic acids; _viz._ that the latter is not a compound of muriatic acid and oxygen, but a simple substance, and that the former is a compound of this substance with hydrogen. the more general principle connected with these opinions, that oxymuriatic acid is, like oxygen, an acidifying element, forming with inflammables and metals an extensive series of analogous compounds, leads still more directly to the subversion of the established chemical systems, and to an entire revolution in some of the most important doctrines of the science." dr. murray entered the lists as the avowed partisan of the theory of berthollet; dr. davy, on the other hand, appeared as the champion of his brother's doctrine. a severe contest ensued, and both combatants displayed equal skill and strength. the object of the former was to demonstrate the presence of water, or its elements, as a constituent part of muriatic acid; and he proposed to determine the point by combining the dry gases of muriatic acid and ammonia; for as these bodies did not contain its elements, should water appear, he maintained that it must be considered as pre-existing in the muriatic acid; while, on the contrary, if no water could be procured, it would be unphilosophical to suppose it present, but that muriatic acid gas must, in that case, be considered as a compound of hydrogen and chlorine. in performing this experiment, dr. murray did succeed in obtaining a portion of water; but the inference from such a fact was questioned on the other side, upon the assumption of the humidity of the gases. as all parties, however, seemed to agree, that if every source of error could be excluded, the combination of these gases would furnish an _experimentum crucis_, by which the truth or fallacy of either theory might be established, davy, when at edinburgh, was desirous of repeating the experiment with dr. hope, and it was accordingly made in the college laboratory. sir george mackenzie, mr. playfair, and some other gentlemen, were present. the results were communicated in nicholson's journal by dr. davy, and may be briefly stated as follows:--the alkaline and acid gases were pure, and both had been previously dried by exposure for sixteen hours to substances having a strong attraction for water. the apparatus consisted of a plain retort of about the capacity of twenty-six cubic inch measures, with a stop-cock; and of a receiver, with a suitable stop-cock. the latter was filled over mercury with one of the gases, which from the receiver passed into the exhausted retort by means of the stop-cocks; the other gas was introduced the same way into the retort; and thus alternately about ninety cubic inches of each gas were combined. all the salt having then been driven into the bulb of the retort by the heat of a spirit lamp, the neck was cooled and kept cold by moistened cloths, whilst the bulb was heated by a coke fire, till the muriate began to sublime, and to make its appearance at the curvature of the vessel when the fire was withdrawn. the result was then examined, while the bottom of the retort was still very hot: a dew, just perceptible, was observed lining the cold neck. the quantity of water was so extremely small, that the globular particles composing this dew could scarcely be perceived by the naked eye; now the quantity of water, according to hypothesis, should equal no less than eight grains. there is no small difference, it must be confessed, between that quantity and a dew barely perceptible, and which may reasonably be referred to a minute quantity of vapour in the gases, or to a little moisture derived from the mercury, a small quantity of which entered the retort with the gases. dr. hope wished to ascertain how much water would produce such a dew as was observed. for this purpose he heated in a retort, of a similar size to that used in the experiment, a single drop of water, which it may be said weighs about a grain. the appearance of condensed water, in this instance, in the neck of the retort, was much greater than in the preceding: he considered it as being three or four times as great.[ ] [ ] sir humphry davy, during some experiments on the diamond, subsequently ascertained that less than th of a grain of water is sufficient to produce a sensible dew on a polished surface. from these results it may be concluded, on dr. murray's own ground of reasoning, that water is not a constituent part of muriatic acid gas, and that this substance is a compound merely of chlorine and hydrogen; for it is easy to account for the presence of about one-third of a grain of water from various sources, while it is impossible to account for the absence of eight grains upon any theory except that which supposes the gas to be _anhydrous_. i shall not pursue the numerous other experiments by which it was attempted to prove the fallacy of davy's views; they all turn upon the same point, and were refuted by the same vigorous methods of enquiry. the chloridic theory may therefore now be considered as fully established: the philosophers who were for so long a period hostile to its reception, have at length yielded their assent; and berzelius, in a paper published in the "annales de chimie," on the subject of sulpho-cyanic acid, has unconditionally tendered his allegiance; while the subsequent discovery of iodine and bromine has confirmed, by the most beautiful analogies, the views so satisfactorily explained by experiment. as to the claim of priority which has been urged by several philosophers in favour of the french chemists, davy, in speaking of gay lussac's paper, published in the "annales de chimie" for july , observes, that "the historical notes attached to it are of a nature not to be passed over without animadversion. m. gay lussac states, that he and m. thénard were the first to advance the hypothesis that chlorine was a simple body; and he quotes m. ampère as having entertained that opinion before me. on the subject of the originality of the idea of chlorine being a simple body, i have always vindicated the claims of scheele; but i must assume for myself the labour of having demonstrated its properties and combinations, and of having explained the chemical phenomena it produces; and i am in possession of a letter from m. ampère, that shows he has no claims of this kind to make."[ ] [ ] royal institution journal, vol. i. p. . the question of priority appears to me to be readily settled by a reference to printed documents. davy published his "elements of chemical philosophy" in , containing a systematic account of his new doctrines concerning the combinations of simple bodies. chlorine is there placed in the same rank with oxygen, and finally removed from the class of acids. in , m. thénard published the first volume of his "traité de chimie elémentaire théorique et pratique," in which he states the composition of oxymuriatic acid as follows:--"_composition_. the oxygenated muriatic gas contains the half of its volume of oxygen gas, not including that which we may suppose in muriatic acid." it was not until the year , that, by a note in his fourth volume, he appears to have at all relaxed in his attachment to the old theory of lavoisier and berthollet; and it will presently appear, that at the period above mentioned, iodine had been discovered, and its analogies to chlorine fully established, by the sagacity of davy. having, as i trust, offered an impartial view of his claims to the establishment of the chloridic theory, i shall resume my narrative of those events which more immediately connect themselves with his personal history at this period. the great fame of davy, and the high importance of the discoveries which had bestowed it, became a general theme of admiration throughout the scientific circles of europe, and induced the members of the dublin society to invite him to that city, for the purpose of delivering a course of lectures. from the authentic documents which have been placed in my hands, i am enabled to give a particular account of this transaction. at a meeting of the dublin society held on the rd of may , the following resolutions were proposed and unanimously carried, _viz._ . "that it is the wish of the society to communicate to the irish public, in the most extended manner consistent with the other engagements of the society, the knowledge of a science so intimately connected with the improvement of agriculture and the arts, which it is their great object to promote; and that, with this view, it appears to them extremely desirable to obtain the fullest information respecting the recent discoveries made by mr. davy, in electro-chemical science. . "resolved, that application be made to the royal society, requesting that they will be pleased to dispense with the engagements of mr. davy, so far as to allow the dublin society to solicit the favour of his delivering a course of electro-chemical lectures in their new laboratory, as soon as may be convenient after their present course of chemical lectures shall have been completed by their professor mr. higgins. . "that the sum of four hundred guineas be appropriated out of the funds of the society, to be presented to mr. davy, as a remuneration for the trouble and expense which they propose he should incur, and as a mark of the importance they attach to the communication which they solicit." mr. leslie foster having stated to the dublin society that the "farming society of ireland" were desirous of availing themselves of this opportunity to apply to mr. davy to repeat before them the six lectures on the application of chemistry to agriculture, which he delivered this year ( ) to the board of agriculture in england, and that they requested the dublin society would accommodate them with the use of their laboratory for that purpose, all the members of the dublin society having free admission to such lectures-- the following resolutions were passed by the dublin society:-- "that in the event of mr. davy coming over to ireland, and consenting to deliver the course referred to, the farming society shall be accommodated with the use of the laboratory, according to their request. "that it be referred to the committee of economy to consider on what terms, and under what regulations, it may be expedient to issue tickets of admission to the electro-chemical course, so as to reimburse to the society the expenses attendant on the arrangement; and that, in order to give the fullest effect to such regulations, the members of the society renounce any claim to gratuitous admission to this course." a letter having been addressed to mr. davy by the secretary of the society, inviting him to dublin, for the purpose of delivering courses of lectures, in conformity with the foregoing resolutions, the following answer was received from him:-- to john leslie foster, esq. m. p. secretary to the dublin society. may , . sir, i had the honour of communicating your letter to the president and council of the royal society, who have desired me to express to you, sir, and through you, to the dublin society, the lively interest they feel in the prosperity of that useful public body, and the desire that they have to promote its important object. on these grounds, they have been pleased to permit me to be absent from the meetings of the royal society, during the period that may be necessary for delivering a course of lectures at the laboratory of the dublin society, in the month of november next. be pleased to express to the dublin society my grateful acknowledgments for the honour they have done me in making such a proposition; and assure them that i shall use my best exertions to promote their views for the extension of chemical science, and every other species of useful knowledge. i beg to be permitted to thank you, sir, for the flattering manner in which you had the goodness to convey to me their proposal. i am, sir, with great respect, your obliged and obedient servant, h. davy, sec. r. s. on the commencement of the course, on the th of november , three hundred and seventy-one admission tickets had been issued; and the committee of chemistry having expressed their opinion to the society, that the lecture-room would not afford accommodation for a greater number of persons, the assistant secretary was directed to limit his tickets to that number. on the th instant, however, the number was increased to four hundred, without inconvenience. at the close of the course, on the th of november, the dublin society passed the following resolutions:-- "resolved, that the thanks of the society be communicated to mr. davy for the excellent course of lectures which, at their request, has been delivered by him in their laboratory; and to assure him that the views which led the society to seek for these communications, have been answered even beyond their hopes;--that the manner in which he has unfolded his discoveries has not merely imparted new and valuable information, but further appears to have given a direction of the public mind towards chemical and philosophical enquiries, which cannot fail in its consequences to produce the improvement of the sciences, arts, and manufactures in ireland. "that the thanks of the society be communicated to the royal society for their ready compliance with our request, in dispensing with the engagements of mr. davy, during the last six weeks. "that mr. davy be requested to accept the sum of five hundred guineas from the society."[ ] [ ] there were four hundred tickets issued for the course, sixty of which were honorary; the produce of the remainder amounted to _l._ _s._ _d._ davy received _l._; and the surplus went to officers and servants, and for the discharge of incidental expenses. the following letter appears, from the date, to have been written about a week before his arrival in dublin. to thomas poole, esq. october , . my dear poole, upon every occasion your recommendation, or opinion, would have great weight with me. amongst the candidates for the office of clerk to the royal society, there is one mr. w----, that i am well acquainted with, and who was formerly attached to the royal institution. he appears to me, as well from his scientific character, as from his habits and pursuits, to be admirably fitted for the situation. i advised him nearly two months ago, in consequence of a conversation with sir joseph banks, to offer himself for the situation. i cannot therefore interest myself for any other person who does not possess superior qualifications. sir joseph's maxim, which i hope will be adopted by all the members, is--"let it be given to the most worthy." i have no doubt that mr.---- would fill the situation with credit, and that he is a very worthy man; but, from all that i can learn, his claims are much inferior to those of w----. we want not merely a civil, gentlemanlike, honest man, but a man a little accustomed to calculation, to astronomical observation, and to experiment. i am in a delightful country here--the valley of the tyne--enjoying a few days' leisure after a rather hard chemical campaign, and preparing health and spirits for another in ireland, where i am going next week. i hope to be in london by the first week in december. i intend next summer to go into cornwall--god willing; and i will not go through without seeing you, and telling you that, under all circumstances, i shall always think of you with the warmest esteem, and shall always be your sincere friend, h. davy. in the following year, davy was again solicited by the dublin society to deliver lectures in their laboratory; and at a meeting of the members on the th of june , a series of resolutions were passed, by which he was empowered to procure copies of many of the geological sketches referred to in a course of lectures he had delivered on geology at the royal institution; and also to superintend the construction of a large voltaic battery, for the illustration of the proposed lectures. in compliance with this request, davy delivered two distinct courses; one on the elements of chemical philosophy, the other on geology, for which he received the unanimous thanks of the society, and as a more substantial testimony of their gratitude, the sum[ ] of seven hundred and fifty pounds; the receipt of which davy acknowledged by the following letter. [ ] these courses were more numerously attended than those in , there having been issued about five hundred and twenty-five tickets; the proceeds of which were _l._ _s._ to b. mac carthy, esq. assistant secretary to the dublin society. dublin, december , . sir, i have received your letter, inclosing a draught for seven hundred and fifty pounds irish. i am very much gratified by the thanks of the dublin society, for the courses of lectures which i had the honour of delivering in their laboratory; and i am proud of their opinion, that they will be useful to the irish public. the attention, candour, and indulgence with which they were received by the audience, i shall remember with the warmest feelings of gratitude as long as i live. i have the honour to be, sir, with much esteem, your obliged and obedient servant, h. davy. before he quitted dublin, the provost and fellows of trinity college conferred upon him the honorary degree of ll.d., as an expression of the high admiration which his eminent scientific merits had so universally commanded. in the month of august, in the same year, his opinion was requested by a committee, as to the best method to be adopted for ventilating the house of lords; to which circumstance he alludes in the following note to his friend mr. pepys. august , . my dear pepys, i find that i am engaged on wednesday, to meet lord liverpool, at the house of lords, to consider a mode of ventilating it. this business, most unluckily, will prevent my accompanying you; but i shall be glad to go with you on some other day, and to touch up the trout at cheynies, and afterwards to proceed to serge hill. very affectionately yours, h. davy. this undertaking, it must be allowed, was on davy's part a most complete failure: whether he had miscalculated the diameter and number of the apertures necessary for establishing a current, it is difficult to say, but it was obvious that the stream of fresh air thus introduced was by no means adequate to the demand for it.[ ] [ ] in february , he exhibited a model, in one of his lectures at the royal institution, in illustration of his plan; from which it appeared that the air deteriorated by respiration was conducted through three copper pipes, terminating in a single tube, to the roof of the building; and by means of ventilators below, there was a constant supply of fresh air, the circulation of which was promoted by a furnace. the failure, so vexatious to davy, became to others a fertile source of pleasantry, and numerous epigrams, not exactly of a character to meet the public eye, were very generally circulated, and which, in recording the miscarriage of science, displayed the triumph of wit. the scientific renown of davy having attracted the attention of his late majesty, at that time prince regent, he received from his royal highness the honour of knighthood, at a levee held at carlton house, on wednesday, the th of april ; and it may be remarked, that he was the first person on whom that honour had been conferred by the regent. on the day following this occurrence, sir humphry delivered his farewell lecture before the members of the royal institution; for he was on the eve of assuming a new station in society, which induced him to retire from those public situations which he had long held with so much advantage to the world, and with so much honour to himself. how far such a measure was calculated to increase his happiness i shall not enquire; but i am bound to observe, that it was not connected with any desire to abandon the pursuit of science, nor even to relax in his accustomed exertions to promote its interests. it was evident, however, to his friends, that other views of ambition than those presented by achievements in science, had opened upon his mind: the wealth he was about to command might extend the sphere of his usefulness, and exalt him in the scale of society: his feelings became more aristocratic, he discovered charms in rank which had before escaped him, and he no longer viewed patrician distinction with philosophic indifference. on the th of april , sir humphry married mrs. apreece, the widow of shuckburgh ashby apreece, esq. eldest son of sir thomas apreece: this lady was the daughter and heiress of charles kerr, of kelso, esq. and possessed a very considerable fortune. immediately after the celebration of the marriage, sir humphry and his bride proceeded to the hospitable mansion of sir john sebright, and afterwards made a tour through scotland, receiving wherever they went the most flattering marks of attention. during their excursion, davy wrote various letters to his scientific friends, several of which i shall introduce; but, in order that those to mr. children may be understood, it will be necessary that the reader should be made acquainted with a transaction which occurred in the year . in consequence of some conversation on gunpowder, during which davy observed that its composition might be greatly improved by rendering it less _hygrometric_, a proposition was started, that he should join mr. children and mr. burton in establishing a manufactory for its preparation upon chemical principles. whether davy considered himself, in the strict commercial sense, a partner, or merely a chemical adviser, it is perhaps not easy to determine; but it is quite clear that both mr. children and mr. burton considered him in the former light, although it is an act of justice to those gentlemen to state, that the very moment davy expressed his disinclination to such an arrangement, they immediately, without the slightest hesitation, released him from all responsibility. this i am enabled to assert, after a most careful investigation of all the correspondence that passed upon the occasion. to john george children, esq. harewood house, july , . my dear friend, i am very sorry that i missed you the day before i set out on my journey. you will have learnt from your solicitor that i signed the articles. i still think i shall return before any powder will be made, at least if you do not make it till december, for our present intention is to be in town early in that month. i sent to you an imperfect copy of my book,[ ] in which there were no engravings, and in which one cancel was not inserted, thinking that you would prefer a copy sent in that way: the cancelled leaf, which you have not, contains a correction for the quantity of nitrous acid gas and water to form the crystalline compound, which is the base of oil of vitriol. three parts nitrous acid gas condense four parts sulphurous gas. i have my little apparatus, which will enable me to pursue my experiments on gunpowder. there is one conclusion very obvious resulting from the new facts,--a _perfect_ gunpowder ought to contain no more charcoal than is necessary to convert the oxygen of the nitre into carbonic acid. sulphur forms from nitre just as much elastic fluid as charcoal, _i. e._ if similar quantities of nitre be entirely decomposed, one by charcoal, and one by sulphur, and if the sulphurous gas and the carbonic acid gas be compared, their volumes will be equal. the advantage of forming carbonic acid gas is, that it is more readily disengaged from the alkali. now it is a question, whether sulphur will decompose _sulphate_ of potash,--it will decompose the carbonate; of this we are sure. there ought, then, to be just as much sulphur as will form sulphuret of potash with the potash: of nitre, · of charcoal, and of sulphur, are the true proportions for forming nothing but sulphuret of potash and elastic matter. pray send me some cards to circulate; address to me, post office, edinburgh. i hope you got cavendish's balance. i have been here for two days:--it is a very magnificent place: good fishing for pike, trout, and grayling. lady d. desires her kind remembrances. i am, my dear friend, most affectionately yours, h. davy. [ ] "elements of chemical philosophy," to be presently noticed. to the same. dunrobin castle, near golspie, august . my dear friend, i hope you are making progress in our manufactory. i shall expect, on my return, to find your powder the best and strongest, and to make trial of it. i wish i had some of it here, the black-cock and grouse would feel its efficacy. i have been expecting a letter from you every day. this house is so delightful, the scenery so grand, and the field-sports so perfect, that i think we shall not quit it for a fortnight. i went to inverness and fished for salmon. i also went to two or three other places, but not one did i catch till i arrived here. the first day i landed seven noble ones, and played three more in four or five hours. the next day i played eight and landed three, besides white trout in abundance. i have shot only one day, for a few hours; but we found grouse at every fifty yards, and i shot seven. we are just going to try sea-fishing. pray write to me a little news of what is doing for science and the world. i beg you will remember me most kindly to your father and to dr. babington, and brande, when you see them. i am, my dear friend, most affectionately yours, h. davy. to william clayfield, esq. dunrobin, near golspie, august , . dear clayfield, i am much obliged to you for two very kind letters, and for a box containing specimens from st. vincent.[ ] i beg you will thank the gentleman who was so good as to cause them to be collected for me. the box followed me to inverness. the ashes, i think, are likely to fertilize barbadoes. there is a parallel case of materials having been carried so far in the eruption in iceland in . i have been with my wife making a tour through the north since the beginning of july. we have arrived at our extreme point, and shall slowly proceed south in about a fortnight. i wish you could be of our party here; we are in a delightful house, that of lord stafford, in a country abounding with fish and game. i have caught about thirty salmon since i have been here, and killed grouse, wild ducks, teal, &c. i have not yet shot a stag, but i hope to do so this next week. i have just published a volume of the elements of chemistry, and i hope to publish another in the course of the spring. having given up lecturing, i shall be able to devote my whole time to the pursuit of discovery. i have not sent you a copy of my book, for i have thought that the best mode of avoiding giving offence to some, was by not making presents at all. had i not so determined, one of the first copies would have been sent to you, as a mark of the warm esteem and regard of your affectionate friend, h. davy. [ ] specimens of substances ejected from the crater in that island, which mr. clayfield forwarded to davy, in consequence of having heard that he had been engaged in examining the sand collected at barbadoes, and which was a product of the same eruption. to samuel purkis, esq. dunrobin castle, aug. , . my dear purkis, you may probably be surprised to receive a letter from me from this remote corner of the north; but i owe you a letter, and i have a great inclination, wherever i may be, to discharge all debts, and particularly those rendered due by kindness. receive my warm acknowledgments for your kind congratulations on my becoming a benedick. i can now speak from experience, in which you have long participated. i am convinced that the natural state of domestic society is the best fitted for man, whether he be devoted to philosophy, or to active life. i shall have much pleasure in presenting my wife to you and to mrs. purkis, on my return. we have had a delightful tour through the highlands. we are at the extreme point of our journey. the pleasures of a refined society--that of lord and lady stafford's family--have induced us to make a long pause here. we think we shall be in london the beginning of december. i have spent some days such as we passed together in wales. we have had all the varieties of river, mountain, and wood scenery. the lakes of scotland are infinitely finer than those of wales; but the glens of the principality may fairly stand in competition with those of the highlands. i hope i shall find you and your family in good health, and that you will have spent a very pleasant summer. i am, my dear purkis, very sincerely and affectionately yours, h. davy. to john george children, esq. dunkeld, sept. , . my dear friend, i have received your two kind letters. i hope your quiet life, and reasonable medical discipline, will entirely restore your health. we are now on our return, and probably shall arrive in london before the middle of november: our time, however, is uncertain, as the election may hasten, or keep us back for want of horses. i can do nothing respecting the licence till my return; i will then see mr. wharton, or mr. vansittart. i have another subject of conversation in which they are interested, and i can easily introduce that of gunpowder. i have been tolerably successful as a shot lately. i have not fished. my last adventure was at the spey, near gordon castle, where i killed some noble salmon. at blair athol i shot some ptarmigans and a stag. i am now at dunkeld, which i think the most beautiful habitable spot in the highlands. the tay, a noble river, rolls with a majestic stream through lofty woods seated upon cliffs and rounded hills; and in the background are the mountains of benyglor and the hills of killycrankie. my wife desires her kind remembrances. pray offer mine to your father and daughter, and believe me to be always most affectionately yours, h. davy. to the same. edinburgh, october . my dear friend, we are on our return: i am well, but i am sorry to say that lady d. is very much indisposed, and anxiety for her hastens my journey to town. * * * * * i have received a very interesting letter from ampère. he says that a combination of chlorine and azote has been discovered at paris, which is a fluid, and explodes by the heat of the hand; the discovery of which cost an eye and a finger to the author. he gives no details as to the mode of combining them. i have tried in my little apparatus with ammonia cooled very low, and chlorine, but without success. there is little doing here ... dresses and dances. sir james hall is writing on a sort of deluge. playfair is the true and amiable philosopher. my brother is making experiments on animal matter. i hope your gunpowder works are nearly finished. i shall be at the opening ball. as soon as i return i shall give my mind up to this matter. my wife desires her kind remembrances. mine to your worthy father and anna. god bless you, my dear friend, and believe me ever affectionately yours, h. davy. on his return to town, after this tour, the following letter was addressed to his friend at tonbridge:-- october , . my dear children, i have just seen pepys, and rejoice that he gives me so good an account of your health. my wife is much better, except that she has a swollen foot. i have never seen her in such good health and spirits. she is resolved to lead a home life of perfect quiet for six weeks, and i fear you will not be able to tempt her to quit her fire-side, though there is no visit she would make with greater pleasure: but lameness does not suit the country; and for one so enthusiastically fond of nature, it would be vexatious to be in the country, and not to be able to enjoy hills, and meads, and woods. but i am ready to come to my business whenever you think i can be useful. i shall set to work to make gunpowder with as much ardour as miles peter--i hope with similar results. i shall not be able to endure a very long separation from my wife, but for three or four days i am at your command. i have been working yesterday and to-day on some new objects; and we are to have a meeting on wednesday, at one o'clock, at the institution, to try to make this compound of azote and chlorine, and to try some other experiments. afterwards we (angling chemists) propose a dinner at brunet's. if you can come to town on that day, i will promise to return with you. god bless you, my dear children, and believe me to be most affectionately yours, h. davy. chapter ix. davy's "elements of chemical philosophy" examined.--his memoir on some combinations of phosphorus and sulphur, &c.--he discovers hydro-phosphoric gas.--important illustrations of the theory of definite proportionals--bodies precipitated from water are hydrats.--his letter to sir joseph banks on a new detonating compound.--he is injured in the eye by its explosion.--his second letter on the subject.--his paper on the substances produced in different chemical processes on fluor spar.--his work on agricultural chemistry. the "elements of chemical philosophy," a work to which he has alluded in several of the preceding letters, was published in june . it is dedicated to lady davy, to whom he offers it "as a pledge that he shall continue to pursue science with unabated ardour." this work, although only a small part of the great labour he proposed to accomplish, must be considered as one of high importance to the cause of science. it has not perhaps announced any discoveries which had not been previously communicated to the royal society, but it has brought together his original results, and arranged them in one simple and digested plan--it has given coherence to disjointed facts, and has exhibited their mutual bearings upon each other, and their general relations to previously established truths. very shortly after the publication of this first part, it was asserted by a scientific critic that the work could never be completed upon the plan on which it had commenced, which was little less than a system of chemistry, in which all the facts were to be verified by the author: an undertaking far too gigantic for the most intrepid and laborious experimentalist to accomplish. there was too much truth in the remark:--the life of the author has closed--the work remains unfinished. although it bears the title of "elements," its plan and execution are rather adapted for the adept than the tyro in science; it has, however, enabled the discoverer to expand several of his opinions with a freedom which is not consistent with the studied compression and elaborate brevity that necessarily characterise the style of a philosophical memoir,--and thus far it may have served the more humble labourer. the first impression which this volume must produce, is that of admiration at the rapid and triumphant progress of chemistry, during the period of a very few years; while a comparison of this work with others, even of very recent date, will show how much we are indebted for this progress to the unrivalled labours of davy. the first part of his projected system, which constitutes the volume under review, extends only to the general laws of chemical changes, and to the primary combinations of undecompounded bodies. it is resolved into seven divisions, upon each of which i propose to offer some remarks. the first division embraces the consideration of the three different forms of matter, _viz._ solidity, liquidity, and elastic fluidity; and that of the active powers on which they depend, and by which they are changed, such as gravitation, cohesion, calorific repulsion, or heat, and attractions chemical and electrical;--the laws of which he has expounded in a lucid and masterly manner; although it will be only necessary to quote the following passage, to show that the greatest philosopher may occasionally slide into error. "in solids, the attractive force predominates over the repulsive; in fluids, and in elastic fluids, they may be regarded as in different states of equilibrium; and in ethereal substances, the repulsive must be considered as predominating over and destroying the attractive force." a reviewer has very justly observed, that it is difficult to conceive how so much error and confusion could have been collected, by such an author, into so short a sentence. it is a solecism to say that two forces may exist in different states of equilibrium; besides, it is generally admitted that the repulsive force alone exists in elastic fluids, and that it is only compensated by external pressure, or gravitation. in treating the subject of heat, he maintains the same opinion, though in a manner somewhat more subdued, as that which he had formed at the very commencement of his scientific career,[ ]--that it is nothing else than motion, and that the laws of heat are the same as the laws of motion. [ ] see page . in taking a general view of the subject of chemical attraction, there is a remarkable clearness in his enunciation of its several propositions, and a great felicity in the selection of its illustrations. he combats the theory of berthollet, respecting the influence of mass, with singular success, and confirms the general law, that all bodies combine chemically, in certain definite proportions to be expressed by numbers; so that, if one number be employed to denote the smallest quantity in which a body combines, all other quantities of the same body will be as multiples of this number; and the smallest proportions in which the undecompounded substances enter into union being known, the constitution of the compound they form may be learnt; and the element which unites chemically in the smallest quantity being expressed by unity, all the other elements may be represented by the relations of their quantities to unity. unfortunately, however, there has existed amongst philosophers a want of agreement as to the _unit_ to which the relative values of the other numbers shall be referred. mr. dalton selected hydrogen as the unit; davy followed his example, but doubled the weight of oxygen; while wollaston, thompson, and berzelius, have proposed oxygen as the most convenient unit, since that element enters into the greatest number of combinations. to dalton is now universally conceded the glory of having established the laws of definite proportions; but in unfolding them, he has employed expressions which involve speculations as to their physical cause, and has thus given to that, which is nothing more than a copious collection of facts, the appearance of a refined theory. it may be perfectly true, as mr. dalton supposes, that all bodies are composed of ultimate atoms; but in the present state of our knowledge, we can neither form any idea of the nature of such atoms, nor of the manner in which they may be grouped together. we are therefore indebted to davy for having, by his early and powerful example, taught the chemist how to disentangle fact from hypothesis, and to investigate the doctrine of proportionals, without any reference to the _atomic_ theory which has been proposed for its explanation. the second division treats of radiant or ethereal matter, and of its effects in producing vision, heat, and chemical changes. it contains some refined speculations respecting the possible conversion of terrestrial bodies into light and heat, and _vice versâ_. the third division presents us with an account of "empyreal undecompounded substances," or those which support combustion; together with that of the compounds which they form with each other. upon this occasion, davy has completely rescued us from the trammels of the anti-phlogistic theory, and has shown that, so far from the process of combustion depending upon the position or transfer of oxygen, it is a _general_ result of the actions of _any_ substances possessed of strong chemical attractions, or different electrical relations, and that it takes place in all cases in which an intense and violent motion can be conceived to be communicated to the corpuscules of bodies, without any regard to the peculiar nature of the substances engaged. the announcement of the general law is followed by a history of the only two undecompounded bodies included under this arrangement, viz. _oxygen_, and _chlorine_.[ ] in naming a class of bodies by their relations to combustion, he distinctly states that he merely intends to signify that the production of heat and light is more characteristic of their actions, than of those of any other substances; and that they are, at the same time, opposed to all other undecompounded substances by their electrical relations, being always in voltaic combinations attracted to, or elicited from the positive surface; whereas all other known undecompounded substances are separated at the negative surface. [ ] _iodine_, _fluorine_, &c. had not been discovered at this period. the fourth division comprises the history of undecompounded inflammables, or acidiferous substances, not metallic, and that of their binary combinations with oxygen and chlorine, or with each other. the bodies considered under this division, are the following:--hydrogen, azote, sulphur, phosphorus, and boracium, or boron. under the history of sulphur, he gives us the true theory of the process by which sulphuric acid is produced by the combustion of that body in mixture with nitre, and which had never before been explained in any chemical work. the fifth division contains the metals; their primary combinations with other undecompounded bodies, and with each other. in the order of classification adopted on this occasion, the newly discovered inflammable metals, producing by combustion alkalies, alkaline earths, and earths, commence the series; next come those which produce oxides; and lastly, those which produce acids. thus are we presented with a chain of gradations of resemblance which may be traced throughout the whole series of metallic bodies. the sixth division comprehends certain bodies (the _fluoric principle_, and the _ammoniacal amalgam_) which present some extraordinary and anomalous results. it is worthy of remark, that, at the period at which this work was written, davy considered the peculiar acid developed from fluor spar, by the action of sulphuric acid, as a compound of an acid unknown in a separate state, and water; whence he proposed to call it _hydro-fluoric_ acid,--a term extremely objectionable from its ambiguity, since it would indicate either hydrogen or water as one of its constituents. at the conclusion, however, of this chapter, in consequence of having observed certain phenomena displayed by this gas, when in combination with silica and boracic acid, he for a moment seems to have caught the truth, but it as quickly eluded his grasp, and he dismisses the conjecture which it was his good fortune some years afterwards to verify, _viz._ that the fluoric acid is a compound of an unknown principle, analogous to chlorine, with hydrogen and water, and that _fluor spar_ is a compound of the same principle with calcium, or the base of lime. the seventh division offers to the chemical enquirer various speculations, as to the probable nature of certain bodies hitherto undecompounded. he observes, that "we know nothing of the true elements belonging to nature; but as far as we can reason from the relations of the properties of matter, that hydrogen is the substance which approaches nearest to what the elements may be supposed to be. it has energetic powers of combination, its parts are highly repulsive of each other, and attractive of the particles of other matter; it enters into combination in a quantity very much smaller than any other substance, and in this respect it is approached by no known body. after hydrogen, oxygen perhaps partakes most of the elementary character: it has a greater energy of attraction, and, with the exception just stated, enters into combination in the smallest proportion." in conclusion, he hints at the possibility of the same ponderable matter in different electrical states, or in different arrangements, constituting substances chemically different, and he thinks that there are parallel cases in the different states in which bodies are found connected with their different relations to temperature: thus, steam, ice, and water, are the same ponderable matter; and certain quantities of steam and ice mixed together produce ice-cold water. "that the forms of natural bodies may depend upon different arrangements of the same particles of matter, has been a favourite hypothesis, advanced in the earliest era of physical research, and often supported by the reasonings of the ablest philosophers. this sublime chemical speculation, sanctioned by the authority of hooke, newton, and boscovich, must not be confounded with the ideas advanced by the alchemists, concerning the convertibility of the elements into each other. the possible transmutation of metals has generally been reasoned upon, not as a philosophical research, but as an empirical process. those who have asserted the actual production of the precious metals, or their decomposition, or who have defended the chimera of the philosopher's stone, have been either impostors, or men deluded by impostors. in this age of rational enquiry, it will be useless to decry the practices of the adepts, or to caution the public against confounding the hypothetical views respecting the elements founded upon distinct analogies, with the dreams of alchemical visionaries, most of whom, as an author of the last century justly observed, professed an art without principles, the beginning of which was deceit, and the end poverty." on the th of june , davy presented to the royal society a paper entitled "on some combinations of phosphorus and sulphur; and on some other subjects of chemical inquiry." by the researches detailed in this memoir, he accomplished three important objects: he established the existence of some new compounds--furnished additional evidence in support of the doctrine of definite proportions--and ascertained that most of the substances obtained from aqueous solutions by precipitation, are compounds of water, or _hydrats_. in the first place, he recognised the formation of two distinct compounds of phosphorus and chlorine: one, solid, white, and crystalline in its appearance; the other, fluid, limpid as water, and volatile. the latter body he found to contain just double as much chlorine as the former. on experimenting upon this latter body with water, he obtained a crystallized substance which he proposed to call _hydro-phosphorous acid_, since it consists of pure phosphorous acid and water. by decomposition in close vessels, it is resolved into phosphoric acid, and a peculiar gas, consisting of one proportional of phosphorus and four of hydrogen, and for which he proposed the term _hydro-phosphorous_ gas. the reader, no doubt, will be immediately struck with the impropriety of a nomenclature in which the prefix _hydro_ is made to express water in the former, and hydrogen in the latter instance. in examining the results of the mutual decomposition of water and the phosphoric compounds of chlorine, davy remarks, that it is scarcely possible to imagine more perfect demonstrations of the laws of definite combination: no products are formed except the new combinations, (phosphoric acid from the solid, phosphor_ous_ acid, from the liquid compound, and in both muriatic acid;) neither oxygen, hydrogen, chlorine, nor phosphorus, is disengaged; and therefore the ratio in which any two of them combine being known, the ratio in which the rest combine, in these cases, may be determined by calculation. lastly, he ascertained that most of the substances obtained by precipitation from aqueous solutions are compounds of water: thus zircona, magnesia, and silica, when precipitated and dried at °, still contain definite proportions of water; and many of the substances which had been considered as metallic oxides, he found, when obtained from solutions, to agree in this respect; and that their colours and other properties are materially influenced by this combined water. on the th of november , was read before the royal society a letter addressed by davy to sir joseph banks, on the subject of the detonating compound already alluded to in his communications to mr. children. he expresses his anxiety to have the circumstances made public as speedily as possible, since experiments upon the substance may be connected with very dangerous results. he had some time before received information from paris of a combination having been effected between chlorine and azote, and that it was distinguished by detonating properties; but he was wholly ignorant of the mode by which it had been prepared, and he could not obtain any information upon this point from any of the french journals. so curious and important a result could not fail to interest him, as he had himself been long engaged in experiments on the action of azote and chlorine, without gaining any decided proofs of their power of combining with each other. it was evident from the notice, that this new body could not be formed in any operations in which heat is concerned; he therefore attempted to combine the elements by presenting them to each other artificially cooled, the azote being in a nascent state. for this purpose he introduced chlorine into a solution of ammonia; a violent action ensued, and minute films of a yellow colour were observed on the surface of the liquor, but they immediately resolved themselves into gas. as he was about to repeat the experiment with some other ammoniacal compounds, mr. children reminded him of the circumstance which he had previously communicated to him in a letter, that mr. james burton, junr, on exposing chlorine to a solution of nitrate of ammonia, had observed the formation of a yellow oil, but which he had not been able to collect. davy availed himself of the hint, and obtained the substance in question: on examining its properties by the application of heat, the tube in which it was contained was shivered to atoms by its explosion, and he received a severe wound in the transparent cornea, which was followed by inflammation, and disabled him from pursuing his enquiry. in the following july, however, he communicated in a second letter to sir joseph banks, the continuation of this enquiry, and furnished a full and satisfactory history of the body in question. having procured it in sufficient quantity, he attempted to effect its analysis by the action of mercury, but a violent detonation occurred, and he was again wounded in the head and hands; fortunately, however, the injury was slight, in consequence of his having taken the precaution to defend his face by a plate of glass attached to a proper cap. in a subsequent experiment, by using smaller quantities, and recently distilled mercury, he succeeded in obtaining results without any violence of action: the mercury united with the chlorine, and the azote was disengaged; from which he was enabled to conclude that it was composed of four volumes of chlorine and one volume of azote. for this new body davy suggested the name of _azotane_; but i have already observed, that his nomenclature of the compounds of chlorine has never been adopted; the detonating substance is now very properly denominated _chloride of nitrogen_. shortly after the publication of this paper, m. berzelius, in a letter to professor gilbert, asserted that "_azotane_" is nothing more than _dry_ nitro-muriatic acid, since it dissolves slowly in water, and forms a weak _aqua regia_. "these few observations," says he, "show clearly that davy's analysis of this substance is inaccurate, and that he corrected his results in consequence of theoretical views." this was an imputation upon the philosophical character of davy, which excited in him no small degree of indignation. in reply he says, "it is difficult to discover what meaning m. berzelius attaches to the term _dry_ nitro-muriatic acid; and it is wholly unnecessary to refute so unfounded and vague an assertion." on july , , a paper was read by davy before the royal society, entitled "some experiments and observations on the substances produced in different chemical processes on fluor spar." the views which he formerly entertained with respect to the fluoric acid have been already noticed:[ ] in the present paper he renounces his previous opinions, and establishes, by experiments of the most satisfactory character, that the base of fluoric acid is a highly energetic body not hitherto obtained in an insulated form, and the properties peculiar to which are as yet unknown. it appears, however, to belong to the class of negative electrics, and, like oxygen and chlorine, to have a powerful affinity for hydrogen and metallic substances. with hydrogen, it constitutes the peculiar and very powerful acid long known by the name of _fluoric acid_,--with boron, the _fluoboric_, and with silicium, the _silicated-fluoric_, acids. although this theory had originally suggested itself to the mind of davy, yet the chemical world is unquestionably indebted to m. ampère for establishing it; and the english chemist has very justly acknowledged the obligation. "during the period that i was engaged in these investigations," says he, "i received two letters from m. ampère, of paris, containing many ingenious and original arguments in favour of the analogy between the muriatic and fluoric compounds. m. ampère communicated his views to me in the most liberal manner: they were formed in consequence of my ideas on chlorine, and supported by reasonings drawn from the experiments of mm. gay lussac and thénard." [ ] see page . it has been stated that davy gave his last public lecture on the th of april ; he however afterwards delivered an occasional lecture to the managers, on his own discoveries, and did not formally resign his professorship until the next year. the following record has been extracted from the journal of the institution. * * * * * "minutes of the proceedings of a general monthly meeting of the members of the royal institution, held on monday, april , . "earl of winchelsea, president, in the chair. "this being the meeting appointed by article . chap. xix. of the bye-laws, for putting in nomination from the chair the professors for the year ensuing, sir humphry davy rose, and begged leave to resign his situation of professor of chemistry; but he by no means wished to give up his connection with the royal institution, as he should ever be happy to communicate his researches, in the first instance, to the institution, in the manner he did in the presence of the members last wednesday, and to do all in his power to promote the interest and success of this institution. "sir h. davy having retired, earl spencer moved, that the thanks of this meeting be returned to sir h. davy, for the inestimable services rendered by him to the royal institution. this motion was seconded by the earl of darnley, and on being put, was carried unanimously. "earl spencer further moved, that in order more strongly to mark the high sense entertained by this meeting of the merits of sir h. davy, he be elected honorary professor of chemistry; which, on being seconded by the earl of darnley, met with unanimous approbation. "the chairman having declared the professorship of chemistry vacant, put in nomination william thomas brande, esq. f.r.s. as a candidate for that office, with a salary of _l._ per annum. "on monday, june , , william thomas brande, esq. was unanimously elected." * * * * * in march , davy published his "elements of agricultural chemistry," being the substance of a course of lectures which he had, for ten successive seasons, delivered before the members of the board of agriculture, to whom the work is inscribed, as a mark of the author's respect. this work, which may be considered as the only system of philosophical agriculture ever published in this country, has not only contributed to the advancement of science, but to that for which he has an equal claim upon our gratitude,--the diffusion of a taste amongst the higher classes for its cultivation; for it has been wisely remarked, that not he alone is to be esteemed a benefactor to mankind who makes an useful discovery, but he, also, who can point out an innocent pleasure. it has been already stated, that davy became early impressed with the importance of the subject:--that in future life its investigation should have been to him so fertile a source of pleasure, may be readily imagined, when it is remembered with what passionate delight he contemplated the ever varying forms of creation. "i am," said he, "a lover of nature, with an ungratified imagination, and i shall continue to search for untasted charms--for hidden beauties." in unfolding, then, the secrets of vegetable life, he did but remove the veil from his mistress. from the same poetical feeling sprang his love of angling: it was a pursuit which carried him into the wild and beautiful scenery of nature, amongst the mountain lakes, and the clear and lovely streams that gush from elevated hills, or make their way through the cavities of calcareous strata.[ ] in the early spring, it led him forth upon the fresh turf in the vernal sunshine, to scent the odour of the bank perfumed by the violet, and enamelled with the primrose, while his heart participated in the renovated gladness of nature. [ ] see his salmonia, edit. . p. . i had hoped that, amidst the voluminous correspondence of my late friend mr. arthur young, some important letters might have been found from davy on agricultural subjects; but the communications which took place between them were generally in conversation, and i have therefore only been able to procure two letters, which i shall here insert: the first will show that, during his tours, his attention was alive to the practices of husbandry; and the second will prove that he had once seriously contemplated the labour of writing the agricultural history of his native county. to arthur young, esq. killarney, june . dear sir, you have been of great and durable service to ireland. i have met with a number of persons who have been enlightened by your labours, and who now follow an enlightened system of agriculture. one very intelligent gentleman you will recollect,--mr. bolton of waterford: he is zealously pursuing improvements, and is instructing his neighbours by precept and example. i am, &c. h. davy. the above letter contains also some observations on a chemical mixture, but which is unintelligible from our being ignorant of the conversation to which it refers. to the same. april, . dear sir, i called this morning with the hope of seeing you, and of gaining some explanation on the subject of your note. i shall not be able to leave london until the middle of july, and i must return early in october. i do not think there would be sufficient time between these periods for accomplishing the objects you mention; nor do i think myself qualified to write upon the agriculture of a county. i wished likewise to devote the leisure of this summer to the preparation of my lectures on the chemistry of agriculture for publication. i have a great deal of information concerning the mineralogy and geology of cornwall, but none concerning the farming. if the business admits of being postponed, i might perhaps be able to accomplish it next summer; that is, by devoting a part of this summer, and the whole of my next: but i would rather confine myself to my own province, the mineralogy and geology of the county, and leave the agriculture to abler hands. be pleased to receive my thanks, and to communicate them to the president for the honour of the proposal. i remain, &c. h. davy. the majority of my readers will probably concur in the wisdom of this decision: they will consider that to have doomed davy to a drudgery of this nature, would have been wasting talents upon an object which might be accomplished by smaller means. from my acquaintance, however, with cornwall, i am induced to form a different opinion. davy never approached even those subjects which had already received from others the most thorough investigation, without extracting from them new and important truths. what, then, might not have been expected from his genius, when applied to a department upon which the light of science had scarcely dawned? it is only in a primitive country like cornwall, that the natural relations between the varieties of soil and the subjacent rocks can be studied with success: as we advance to alluvial districts, such relations become gradually less distinct and apparent, and are ultimately lost in the confused complication of the soil itself, and in that general obscurity which envelopes every object in the ulterior stages of decomposition. we can, therefore, only hope to succeed in such an investigation by a patient and laborious examination of a primitive country, after which we may be enabled to extend our enquiries with greater advantage through those regions which are more completely covered with soil, and obscured by luxuriant vegetation; as the eye, acquainted with the human figure, on gazing upon a beautiful statue, traces the outline of the limbs, and the swelling contour of its form, through the flowing draperies which invest it. the importance of the subject, as well as the general interest it has excited, induce me to offer an analysis of his "elements of agricultural chemistry." the work is divided into eight lectures; and in his introductory chapter, after adverting to the difficulties which the enquiry presents to the lecturer, he offers a general view of the objects of the course, and of the order in which he proposes to discuss them. "agricultural chemistry has not yet received a regular and systematic form. it has been pursued by competent experimenters for a short time only; the doctrines have not as yet been collected into an elementary treatise; and on an occasion when i am obliged to trust so much to my own arrangements, and to my own limited information, i cannot but feel diffident as to the interest that may be excited, and doubtful of the success of the undertaking. i know, however, that your candour will induce you not to expect any thing like a finished work upon a science as yet in its infancy; and i am sure you will receive with indulgence the first attempt made to illustrate it, in a distinct course of lectures. "agricultural chemistry has for its objects all those changes in the arrangements of matter connected with the growth and nourishment of plants; the comparative values of their produce as food; the constitution of soils; and the manner in which lands are enriched by manure, or rendered fertile by the different processes of cultivation." that such objects are intimately connected with the doctrines of chemistry, he proceeds to show by several appropriate and striking illustrations. "if land be unproductive, and a system of ameliorating it is to be attempted, the sure method of obtaining the object is, by determining the cause of its sterility, which must necessarily depend upon some defect in the constitution of the soil, which may be easily discovered by chemical analysis. are any of the salts of iron present? they may be decomposed by lime. is there an excess of siliceous sand? the system of improvement must depend on the application of clay and calcareous matter. is there a defect of calcareous matter? the remedy is obvious. is an excess of vegetable matter indicated? it may be removed by liming, paring, and burning. is there a deficiency of vegetable matter? it is to be supplied by manure." "in the selection also of the remedy, after the discovery of the evil, chemical knowledge is of the highest importance. limestone varies in its composition, and by its indiscriminate application we may aggravate the sterility we seek to obviate. peat earth is an excellent manure, but it may contain such an excess of iron as to be absolutely poisonous to plants. how are such difficulties to be met but by the resources of chemistry? it is also evident that the scientific agriculturist should possess a general knowledge of the nature and composition of material bodies, and the laws of their changes; for the surface of the earth, the atmosphere, and the water deposited from it, must, either together or separately, afford all the principles concerned in vegetation; and it is only by examining the chemical nature of these principles, that we are capable of discovering what is the food of plants, and the manner in which this food is supplied and prepared for their nourishment." davy likewise advocates the necessity of studying "the phenomena of vegetation, as an important branch of the science of organized nature; for, although exalted above inorganic matter, vegetables are yet in a great measure dependent for their existence upon its laws. they receive their nourishment from the external elements; they assimilate it by means of peculiar organs; and it is by examining their physical and chemical constitution, and the substances and powers which act upon them, and the modifications which they undergo, that the scientific principles of agricultural chemistry are obtained." with respect, however, to the practical utility of this latter branch, different opinions have been entertained. i confess, i am inclined to agree with an able reviewer[ ] when he says, "it is the proper business of the chemist to examine and ascertain the nature and properties of dead and inorganized matter, and the various combinations which, according to chemical laws, it is capable of forming. the chemical composition of organized bodies, and of the products which they form, fall likewise under his cognizance; but when he proceeds to consider the physical constitution of these bodies, and the manner in which they act in forming their products, he no longer works with the instruments of the laboratory, or conducts processes which can be properly imitated there." [ ] edinburgh review, vol. , page . in concluding his introductory observations, he remarks upon the prejudice which persons, who argue in favour of practice and experience, very commonly entertain against all attempts to improve agriculture by philosophical enquiries and chemical methods. "that much vague speculation may be found in the works of those who have lightly taken up agricultural chemistry, it is impossible to deny. it is not uncommon to find a number of changes rung upon a string of technical terms, such as oxygen, hydrogen, carbon, and azote, as if the science depended upon words, rather than upon things. but this is, in fact, an argument for the necessity of the establishment of just principles of chemistry on the subject.--if a person journeying in the night wishes to avoid being led astray by the ignis fatuus, the most secure method is to carry a lamp in his own hand." "there is no idea more unfounded than that a great devotion of time, and a minute knowledge of general chemistry, are necessary for pursuing experiments on the nature of soils, or the properties of manures. the expense connected with chemical enquiries is extremely trifling: a small closet is sufficient for containing all the materials required." in the second lecture, he enters upon the consideration of the general powers of matter, such as gravitation, cohesion, chemical attraction, heat, light, and electricity; and then proceeds to examine the elements of matter, and the laws of their combinations and arrangements. to an audience constituted of persons who were not familiar with the elementary principles of the science, it might have been very necessary for the lecturer to enter upon such preliminary details; but there cannot be any good reason for his having published them in his system. as they are to be found in every work on chemistry, it will not be necessary to bestow upon them any further notice. in the third lecture, he enters into a description of the organization and living system of plants; in which he connects together into a general view, the observations of the most enlightened philosophers who have studied the physiology of vegetation--those of grew, malpighi, sennebier, hales, decandolle, saussure, bonnet, darwin, smith, and above all, of mr. knight, whose enquiries upon these subjects are not only the latest, but by far the most satisfactory and conclusive. as there is little in these descriptions that may not be found in the original authors, i shall not unnecessarily trespass upon the time of the reader by relating them. in the latter part of this lecture, he describes the properties and ultimate composition of the proximate principles of which vegetable matter consists, and into which it may be resolved by different processes of art; such are gum, starch, sugar, albumen, gluten, extract, tannin, resin, oils, &c. &c. but since the publication of this work, vegetable analysis has advanced to a degree of refinement which could scarcely have been anticipated in so short a period, and consequently many of his statements appear deficient; but his general directions for conducting an analysis of any vegetable substance, with a degree of accuracy sufficient for the views of the agriculturist, remain unimpeached. the most valuable, and more strictly original part of this lecture, is his statement of the quantity of soluble or nutritive matters contained in varieties of the different substances that are used as articles of food, either for man or cattle, and which he has displayed in a tabular form. the analyses were his own, and were conducted with a view to a knowledge of the general nature and quantity of the products, rather than to that of their intimate chemical composition. he proceeded upon the assumption, that the excellence of the different articles, as food, will be in a great measure proportional to the quantities of soluble matter they afford; although he admits that these quantities cannot be regarded as _absolutely_ denoting their value. albuminous or glutinous matters have the characters of animal substances; sugar is more, and extractive matter less nourishing than any other principles composed of carbon, hydrogen, and oxygen. certain combinations likewise of these substances may be more nutritive than others. there are some principles also, which, although soluble in the vessels of the chemist, pass through the alimentary canal of animals without change; such is _tannin_: on the other hand, there are bodies which, although sparingly soluble in water, are readily acted upon by the gastric juice; _gluten_ is a principle of this description. shortly after dr. wollaston published his scale of chemical equivalents, it occurred to me that by applying the sliding rule to a series of nutritive substances, arranged according to the analyses of davy, some curious and important problems[ ] might be solved; or at least, that the accuracy of the conclusions might be thus conveniently submitted to the test of practice. i accordingly superintended the construction of such an instrument, and submitted it to davy, who expressed his approbation of the principle, but doubted how far the accuracy of his analyses would justify the experiment. [ ] for example:--what weight of wheat is equivalent to a given weight of oats, barley, rye, &c.? suppose three hundred pounds of potatoes feed twenty head of cattle for any given time, how many will the same weight of oats feed? to such a scheme, however, i soon found that there existed a much more serious objection. the operation of the insoluble matter had been wholly neglected; and whatever views the chemist may entertain, the experience of the physiologist has established, beyond doubt, the influence of such matter in the process of digestion. the capacity of the alimentary organs of graminivorous animals sufficiently proves that they were designed for the reception of a _large bulk_ of food, and not for provender in which the nutritive matter is concentrated; and since the gramineous and leguminous vegetables do not present this matter in a separate state, and the animal is not furnished with an apparatus by which he can remove it, the obvious inference is, that he was designed to feed indiscriminately upon the whole; and that, unless bulk be taken into the account, no fair inference can be deduced as to the nutritive value of different vegetables. notwithstanding the difficulties which prevent our arriving at any thing like an accurate conclusion upon so complicated a subject, the results may be received as affording some general views with regard to the comparative value of different nutritive vegetables. it would thus appear that at least a fourth part of the weight of the potatoe consists of nutritive matter, which is principally starch;--that wheat consists of as much as ninety-five, barley of ninety-two, oats of seventy-five, rye of eighty, and peas and beans of about fifty-seven per cent. of nutritive matter. the fourth lecture comprises subjects of the utmost importance, and must be considered as constituting by far the most original and valuable division of the work. it treats of soils,--their constituent parts, their chemical analysis, their uses, their improvement, and of the rocks and strata found beneath their surface. in the execution of this part of his labours, he has not only improved on the processes of fordyce and kirwan, but he has enriched the subject with much interesting and novel research. "soils, although extremely diversified in appearance and quality, consist of comparatively few elements, which are in various states of chemical combination, or of mechanical mixture. "these substances are silica, lime, alumina, magnesia, the oxides of iron, and of manganese; animal and vegetable matters in a state of decomposition; together with certain saline bodies, such as common salt, sulphate of magnesia, sometimes sulphate of iron, nitrates of lime and magnesia, sulphate of potash, and the carbonates of potash and soda. "the silica in soils is usually combined with alumina and oxide of iron; or with alumina, lime, magnesia, and oxide of iron, forming gravel and sand of different degrees of fineness. the carbonate of lime is usually in an impalpable form; but sometimes in the state of calcareous sand. the magnesia, if not combined in the gravel and sand of the soil, is in a fine powder united to carbonic acid. the impalpable part of the soil, which is commonly called clay or loam, consists of silica, alumina, lime, and magnesia; and is, in fact, visually of the same composition as the hard sand, but more finely divided. the vegetable, or animal matters (and the first is by far the most common in soils,) exist in different states of decomposition. they are sometimes fibrous, sometimes entirely broken down and mixed with the soil. "to form a just idea of soils, it is necessary to conceive different rocks decomposed, or ground into parts and powder of different degrees of fineness; some of their soluble parts dissolved by water, and that water adhering to the mass, and the whole mixed with larger or smaller quantities of the remains of vegetables and animals, in different stages of decay." soils, then, would appear to have been originally produced from the disintegration of rocks and strata; and hence there must be at least as many varieties of them, as there are species of rocks exposed at the surface of the earth; and they may be distinguished by names derived from the rocks from which they were formed. thus, if a fine red earth be found immediately above decomposing basalt, it may be denominated _basaltic_ soil. if fragments of quartz and mica be found abundant, it may be denominated _granitic_ soil; and the same principles may be extended to other analogous cases. a general knowledge then of geology becomes essential to the scientific agriculturist, not only to enable him to form a correct judgment with respect to the connection between the varieties of soil and the subjacent rocks, but to direct him to the different mineral substances which may be associated together in their vicinity, and which may contain principles capable of extending their fertility, or of correcting the circumstances upon which their poverty or barrenness may depend. with this conviction, davy proceeds to offer a general view of the nature and position of rocks and strata in nature; but which, i confess, appears to me to be wholly useless to those who have any acquaintance with the subject, and far too meagre to convey any instruction to those who have not made this branch of science an object of study. upon this view, however, he has grounded a number of valuable remarks; although his observations appear to have been too limited to enable him to do justice to a subject of such extent and importance. had he fulfilled his intention of making a survey of the county of cornwall, the science must have been greatly advanced by his labours, for there is no district in great britain so rich in fact, and so capable of elucidating the history of soil, and the advantages of cultivation, when conducted on the principles of chemical philosophy. the soils superincumbent upon the different rocks are distinct and characteristic; and even in the same species varieties may be observed, in consequence of geological peculiarities. i have, for instance, found that the fertility of a granitic soil is increased by the abundance of felspar in the parent rock;--that of a slaty soil by the degree of inclination or dip of the strata: but the most extraordinary circumstance perhaps connected with this subject, is the very remarkable fertility of the land which lies over the junction of these rocks,--so obvious indeed is it, that the eye alone is sufficient to trace it. we are indebted to the author, in this lecture, for some very ingenious and important remarks on the relations of different soils to heat and moisture, and for a series of experiments by which his views are supported. some soils, he observes, are more easily heated and more easily cooled than others: for example, those that consist principally of a stiff white clay are heated with difficulty; and being usually very moist, they retain their heat only for a short time. _chalks_ also are difficultly heated; but being dryer, they retain their heat longer, less being consumed in the process of evaporation. a black soil, and those that contain much carbonaceous or ferruginous matter, acquire a higher temperature by exposure to the sun, than pale-coloured soils. when soils are perfectly dry, those that most readily become heated, most rapidly cool; but the darkest-coloured dry soil, abounding in animal and vegetable matters, cools more slowly than a wet pale soil, composed entirely of earthy matter. these results davy gained by experiments made on different kinds of soils, exposed for a given time to the sun, and in the shade; the degrees of heating and cooling having been accurately ascertained by the thermometer. nothing can be more evident, than that the genial heat of the soil, particularly in spring, must be of the highest importance to the rising plant. and when the leaves are fully developed, the ground is shaded, and any injurious influence, which in the summer might be expected from too great a heat, entirely prevented; so that the temperature of the surface, when bare and exposed to the rays of the sun, affords at least one indication of the degree of its fertility; and the thermometer may therefore be sometimes a useful instrument to the purchaser or improver of lands. water is said to exist in soils, either in a state of chemical combination, or of cohesive attraction. it is in the latter state only that it can be absorbed by the roots of plants, unless in the case of the decomposition of animal and vegetable substances. the more divided the parts of the soil are, the greater is its attractive power for water; and the addition of vegetable and animal matters still farther increases this power. the quality of soils to absorb water from air, is much connected with fertility. davy informs us that he has compared this absorbent power in numerous instances, and that he always found it greatest in the most productive lands: he states, however, the important fact, that those soils, such for instance as stiff clays, which take up the greatest quantity of water, when it is poured upon them in a fluid form, are not such as absorb most moisture from the atmosphere in dry weather. they cake, and present only a small surface to the air, and the vegetation on them is generally burnt up almost as readily as on sands. there is probably no district in which the importance of moisture in relation to fertility is more apparent than in cornwall; and there is a provincial saying, that the land will bear a shower every weekday, and two upon a sunday: indeed, of such importance is moisture, that it is by no means an uncommon practice to encourage the growth of weeds, in order to diminish the evaporation; a necessity which arises from the excess of siliceous matter in the soil. to those who are disposed to prosecute this enquiry, i should recommend a perusal of mr. leslie's treatise on the "relations of air to heat and moisture." i must not quit the consideration of this lecture, without adverting to the directions with which its author has furnished the philosophical farmer for analysing the different varieties of soil; and which are so clear, so perfect, and above all so simple, that they are now introduced into all elementary works on chemistry, as the only guide to such researches. his method for ascertaining the quantity of carbonate of lime in any specimen, consists in determining the loss of weight which takes place on its admixture with muriatic acid; for since carbonate of lime, in all its states, contains a determinate proportion of carbonic acid, it is evident that, by estimating the quantity of elastic matter given out, the proportion of carbonate of lime will be known. for conducting this experiment, he contrived a very simple and ingenious piece of pneumatic apparatus, in which the bulk of the carbonic acid is at once measured by the quantity of water it displaces. in his fifth lecture he enters upon the nature of the atmosphere, and its influence on vegetables: he also examines the process of the germination of seeds, and the functions of plants in their different stages of growth; and concludes with a general view of the progress of vegetation. i shall merely mention a few of the more interesting points in this enquiry. in illustrating the importance of water to the vegetable creation, he observes that the atmosphere always contains water in its elastic and invisible form, the quantity of which will vary with the temperature. in proportion as the weather is hotter, the quantity is greater; and it is its condensation by diminution of temperature, which gives rise to the phenomena of dew and mist. the leaves of living plants appear to act upon this vapour, and to absorb it. some vegetables increase in weight from this cause, when suspended in the atmosphere, and unconnected with the soil; such are the house-leek, and different species of the aloe. in very intense heats, and when the soil is dry, the life of plants seems to be preserved by the absorbent powers of their leaves; and it is a beautiful circumstance in the economy of nature, that aqueous vapour is most abundant in the atmosphere when it is most needed for the purposes of life; and that when other sources of its supply are cut off, this is most copious.[ ] [ ] the history of his native county would have furnished him with a parallel instance of the intelligence and design which nature displays in connecting the wants and necessities of the different parts of creation, with the power and means of supplying them. in a primitive country like cornwall, the siliceous soil necessarily requires much moisture, and we may perceive that the cause which occasions, at the same time supplies this want; for the rocks elevated above the surface, solicit a tribute from every passing cloud; while in alluvial and flat districts, where the soil is rich, deep, and retentive of moisture, the clouds float undisturbed over the plains, and the country frequently enjoys that uninterrupted series of dry weather which is so necessary to its fertility. linnæus observes, that the plants which chiefly grow upon the summit of mountains, are rarely found in any other situation, except in marshes, because the clouds arrested in their progress by such elevations, keep the air in a state of perpetual moisture. if water in its elastic and fluid states be essentially necessary to the economy of vegetation, so even in its solid form, it is not without its uses. snow and ice are bad conductors of heat; and at a period when the severity of the winter threatens the extinction of vegetable life, nature kindly throws her snowy mantle over the surface; while in early spring the solution of the snow becomes the first nourishment of the plant; at the same time, the expansion of water in the act of congelation, and the subsequent contraction of its bulk during a thaw, tend to pulverise the soil, to separate its parts from each other, and, by making it more permeable to the influence of the air, to prepare it for the offices it is destined to perform. he next proceeds to consider the action of the atmosphere on plants, and to connect it with a general view of the progress of vegetation. he commences with examining its relations to germination. "if a healthy seed be moistened and exposed to air at a temperature not below °, it soon germinates; it shoots forth a _plume_ which rises upwards, and a _radicle_ which descends. "if the air be confined, it is found that, in the process of germination, the oxygen, or a part of it, is absorbed. the azote remains unaltered; no carbonic acid is taken away from the air; on the contrary, some is added." upon this point, critics have been disposed to break a lance with sir humphry. the doctrine, let it be observed, is at variance with the numerous experiments made on this subject by scheele, cruickshank, and de saussure; the results of which agree in proving, that if seeds be confined and made to germinate in a given portion of air, not a _part_ only, but the _whole_ of the oxygen is consumed; and that its place is supplied, not merely by _some_, but by an _equal bulk_ of carbonic acid. objections have been also started to his theory of the chemical changes which the seed undergoes during the process of germination: but were i to enter upon these discussions, time and space would alike fail me, to say nothing of the patience of the reader, which would be exhausted long before we could arrive at any satisfactory conclusion. i shall for the same reasons pass over his observations upon the influence exerted upon growing plants on the air: the subject is involved in much difficulty, which can be only removed by fresh experiments; nor, after all, is the great question, whether the purity of the atmosphere is maintained by vegetation, of any practical moment,--it is one which partakes more of curiosity than of use, and might therefore have been well dispensed with in a system of agriculture. he agrees with many other philosophers in considering "the process of malting as merely one in which germination is artificially produced, and in which the starch is changed into sugar, which sugar is afterwards, by fermentation, converted into spirit. "it is," he continues, "very evident from the chemical principles of germination, that the process should be carried on no farther than to produce the sprouting of the radicle, and should be checked as soon as this has made its distinct appearance. if it is pushed to such a degree as to occasion the perfect developement of the radicle and the plume, a considerable quantity of saccharine matter will have been consumed in producing their expansion, and there will be less spirit formed in fermentation, or produced in distillation. "as this circumstance is of some importance, i made, in october , an experiment relating to it. i ascertained by the action of alcohol, the relative proportions of saccharine matter in two equal quantities of the same barley; in one of which the germination had proceeded so far as to occasion protrusion of the radicle to nearly a quarter of an inch beyond the grain in most of the specimens, and in the other of which it had been checked before the radicle was a line in length; the quantity of sugar afforded by the last was to that in the first nearly as six to five." the whole of this subject appears to be debateable ground between the physiologists and chemists: the one considering the change of starch into sugar as the result of the vital action of the seed; the other affirming that the growth of the germ is in no way necessary to the result, and is to be considered as a mere indication of the due degree of change being effected in the organic matter, or, in other words, that when the organized parts exhibit a certain degree of developement, then the inorganic matter is most completely changed. all growth beyond this is injurious, as leading to a consumption of the inorganic matter. all less than this is not otherwise disadvantageous, than as an indication that the inorganic matter is not duly changed. this change, it is farther affirmed, so far from depending upon vegetable life, can be wrought on the matter of the seed after it is even reduced to powder, or is separated in the form of starch. at all events, it must be admitted as a beautiful arrangement in nature, that the same agents which urge on the developement of the organized parts, should, at the same time, assist in preparing food for their support. from this subject davy is very naturally led to the consideration of the ravages inflicted upon the infant plant by insects; the saccharine matter in the cotyledons at the time of their change into seed-leaves, rendering them exceedingly liable to such attacks. he appears to have bestowed much attention on the turnip-fly, a colyopterous insect, which fixes itself upon the seed-leaves of the turnip at the time that they are beginning to perform their functions. he relates the several remedies which have been proposed for this evil; and from letters which have been put in my possession, addressed to dr. cartwright as early as the year , he appears to have been engaged with that gentleman in experiments made by sprinkling the young plants with lime and urine. after alluding to the parasitical plants of different species, which attach themselves to trees and shrubs, feed on their juices, destroy their health, and finally their life, for which, at present, there does not exist any remedy, he thus concludes his lecture: "to enumerate all the animal destroyers, and tyrants of the vegetable kingdom, would be to give a catalogue of the greater number of the classes in zoology. every species of plant almost is the peculiar resting-place, or dominion, of some insect tribe; and from the locust, the caterpillar, and snail, to the minute aphis, a wonderful variety of the inferior insects are nourished, and live by their ravages upon the vegetable world. "the hessian fly, still more destructive to wheat than the one which ravages the turnip plant, has in some seasons threatened the united states with a famine. and the french government is at this time[ ] issuing decrees with a view to occasion the destruction of the larvæ of the grasshopper. [ ] january . "in general, wet weather is most favourable to the propagation of mildew, funguses, rust, and the small parasitical vegetables; dry weather, to the increase of the insect tribes. nature, amidst all her changes, is continually directing her resources towards the production and multiplication of life; and in the wise and grand economy of the whole system, even the agents that appear injurious to the hopes, and destructive to the comforts of man, are in fact ultimately connected with a more exalted state of his powers and his condition. his industry is awakened, his activity kept alive, even by the defects of climates and season. by the accidents which interfere with his efforts, he is made to exert his talents, to look farther into futurity, and to consider the vegetable kingdom, not as a secure and unalterable inheritance spontaneously providing for his wants, but as a doubtful and insecure possession, to be preserved only by labour, and extended and perfected by ingenuity." his sixth lecture treats of manures of animal and vegetable origin, and of the general principles with respect to their uses and modes of application. it is evident that plants, by their growth, must gradually exhaust the soil of its richer and more nutrient parts; and these can be alone restored by the application of manures. it is equally obvious, that if a soil be sterile from any defect in its constitution, such a defect can be only remedied by artificial additions. hence the introduction of foreign matter into the earth, for the purpose of accelerating vegetation, and of increasing the produce of its crops, is a practice which has been pursued since the earliest period of agriculture. unfortunately, however, the greatest ignorance has prevailed in all ages with regard to the best modes of rendering such a resource available; and the farmer, instead of enriching the soil, has too frequently given his treasures to the winds. "it is quite lamentable," says an intelligent writer,[ ] "to survey a farm-yard in many parts of the kingdom; to see the abundance of vegetable matter that is trodden for months under-foot, over a surface of perhaps half an acre of land, exposed to all the rains that fall, by which its more soluble and richer parts are washed away, or perhaps carried down to poison the water of some stagnant pool, which the unfortunate cattle are afterwards compelled to drink. from the yard, the manure is often carted to the field, at the time when the land is rendered impenetrable by frost; or, if this operation be delayed to a less unseasonable period, it is then frequently laid down in small heaps, or sometimes spread over the surface, exposed for many days to the sun, the winds, and the rain, as if with the direct design of dissipating those more volatile parts which it ought to be the farmer's first endeavour to preserve. [ ] edinburgh review, vol. xxii. p. . "nothing can be so likely to remove ignorance so deplorable, and prejudices so inveterate, as the diffusion of real knowledge concerning the nature of manures, and their mode of action on soils, and on the plants which grow in them." davy, fully sensible of the practical importance of the subject, and impressed with the conviction that it was capable of being materially elucidated by the recent discoveries of chemistry, determined to put forth his strength, in order to bring this department of agriculture under the dominion of science; and upon this occasion our philosopher presents himself in the only character in which he ever ought to appear--in that of an original experimentalist. his first step in the enquiry was to ascertain whether solid substances can pass from the soil through the minute pores in the fibres of the root. he tried an experiment by introducing a growing plant of peppermint into water which held in suspension a quantity of impalpably powdered charcoal: but after a fortnight, upon cutting through different parts of the roots, no carbonaceous matter could be discovered in them, nor were the smallest fibres even blackened,--though this must have happened, had the charcoal been absorbed in a solid form. if a substance so essential to plants as carbonaceous matter cannot be introduced except in a state of solution into their organs, he very justly concludes that other less essential bodies must be in the same case. he also proved by experiment that solutions of sugar, mucilage, jelly, and other principles, unless considerably diluted, clogged up the vegetable organs with solid matter, and prevented the transpiration by the leaves: when, however, this precaution was taken, the plants grew most luxuriantly in such liquids. he next proceeded to determine whether soluble vegetable substances passed in an unchanged state into the roots of plants, by comparing the products of the analysis of the roots of plants of mint which had grown, some in common water, some in a solution of sugar: the results favoured the opinion that they were so absorbed. it appeared, moreover, that substances even poisonous to vegetables did not offer an objection to this law. he introduced the roots of a primrose into a weak solution of oxide of iron in vinegar, and suffered them to remain in it till the leaves became yellow; the roots were then carefully washed in distilled water, bruised, and boiled in a small quantity of the same fluid: the decoction of them passed through a filtre was examined, and found to contain iron; so that this metal must have been taken up by the vessels or pores in the root. if to these facts are added those connected with the changes which animal and vegetable substances undergo by the process of putrefaction, we have all the data necessary for forming a rational theory, to guide us in the management and application of manures. davy has very satisfactorily shown the cases in which putrefaction or fermentation should be encouraged, and avoided. as a general rule, it may be stated, that when manure consists principally of matter soluble in water, its fermentation or putrefaction should be prevented as much as possible; but on the contrary, when it contains a large proportion of vegetable or animal fibre, such processes become necessary. to prevent manures from decomposing, he recommends that they should be preserved dry, defended from the contact of the air, and kept as cool as possible. salt and alcohol, he observes, appear to owe their powers of preserving animal and vegetable substances to their attraction for water, by which they prevent its decomposing action, and likewise to their excluding air. the importance of this latter circumstance he illustrates by the success of m. appart's method of preserving meat. by allowing the fermentation of manure to proceed beneath the soil, rather than in the farm-yard, we not only preserve elements which would otherwise be dissipated, but we obtain several incidental advantages; for example, the production of _heat_, which is useful in promoting the germination of the seed. this must be particularly favourable to the wheat crop, in preserving a genial temperature beneath the surface late in autumn, and during winter. again:--it is a general principle in chemistry, that in all cases of decomposition, substances combine much more readily at the moment of their disengagement, than after they have been perfectly formed. and in fermentation beneath the soil, the fluid matter produced is applied instantly, even whilst it is warm, to the organs of the plant, and consequently is more likely to be efficient than in manure that has gone through the process, and of which all the principles have already entered into new combinations. he examines with much attention the various animal and vegetable matters which have been used as manure, and furnishes the farmer with a number of practical remarks on their nature and mode of operation. for these, the reader must refer to the work itself; for my limits will not allow me to enter into the consideration of _rape-cake_--_malt-dust_--_linseed-cake_--_sea-weeds_--_peat_ --_wood-ashes_--_fish_--_bones_--_hair_,_woollen rags_, _and feathers_--_blood_, &c. &c.; to each of which he assigns peculiar qualities and virtues. as he regards the due regulation of the fermentative process of the utmost importance, he has furnished some valuable hints for the conduct of the farmer upon this occasion. he considers that a compact marle, or a tenacious clay, offers the best protection against the air; and before the dung is covered over, or, as it were, sealed up, he recommends that it should be dried as much as possible. if at any time it should heat strongly, he advises the farmer to turn it over, and thus cool it by exposure to the air; for the practice sometimes adopted of watering dunghills is inconsistent with just chemical views. it may cool the dung for a short time; but moisture, it will be remembered, is a principal agent in all processes of decomposition. in cases of the fermentation of dung, there are simple tests by which the rapidity of the process, and consequently the injury done, may be discovered. if, for instance, a thermometer plunged into the mass does not rise above °, it may be concluded that there is not much danger of the escape of aëriform matter; but should it exceed this, the dung ought to be immediately spread abroad. when a piece of paper moistened in muriatic acid, held over the steams arising from a dunghill, gives dense fumes, it is a certain test that the decomposition is going too far; for this indicates that volatile alkali is disengaged. it may be truly said that, under the hand of davy, the coldest realities blossomed into poetry: the concluding passage of this lecture certainly sanctions such an opinion, and is highly characteristic of that peculiar genius to which i have before alluded.[ ] a subject less calculated than a heap of manure to call forth a glowing sentiment, can scarcely be imagined. [ ] page . "the doctrine," says he, "of the proper application of manures from organized substances, offers an illustration of an important part of the economy of nature, and of the happy order in which it is arranged. the death and decay of animal substances tend to resolve organized forms into chemical constituents; and the pernicious effluvia disengaged in the process seem to point out the propriety of burying them in the soil, where they are fitted to become the food of vegetables. the fermentation and putrefaction of organized substances in the free atmosphere are noxious processes; beneath the surface of the ground they are salutary operations. in this case the food of plants is prepared where it can be used; and that which would offend the senses, and injure the health, if exposed, is converted by gradual processes into forms of beauty and of usefulness; the fetid gas is rendered a constituent of the aroma of the flower, and what might be poison, becomes nourishment to man and animals." the seventh lecture is devoted to the investigation of manures of a mineral origin. he commences the subject by refuting the opinion of schrader and braconnot, that the different earthy and saline substances found in plants arise from new arrangements of the elements of air and water, by the agencies of their living organs. in , he made an experiment on the growth of oats, supplied with a limited quantity of distilled water, in a soil composed of pure carbonate of lime. the soil and the water were placed in a vessel of iron, which was included in a large jar, connected with the free atmosphere by a tube, so curved as to prevent the possibility of any dust, or fluid, or solid matter, from entering into the jar. his object was to ascertain whether any siliceous earth would be formed in the process of vegetation; but the oats grew very feebly, and began to be yellow before any flowers formed. the entire plants were burnt, and their ashes compared with those from an equal number of grains of oat. less siliceous earth was given by the plants than by the grains; but their ashes yielded much more carbonate of lime. numerous other authorities might be quoted to the same effect. jacquin states that the ashes of glasswort (_salsola-soda_) when it grows in inland situations, afford the vegetable alkali; but when on the sea-shore, the fossile or mineral alkali. du hamel also found, that plants which usually grow on the sea-shore, made small progress when planted in soils containing little common salt. the sunflower, when growing on lands not containing nitre, does not afford that substance; though when watered by its solution, it yields nitre abundantly. de saussure made plants grow in solutions of different salts; and he ascertained that, in all cases, certain portions of the salts were absorbed by the plant, and found unaltered in their organs. it may be admitted then as established, that the mineral principles found in plants are derived from the soils in which they vegetate. this fact becomes the foundation of the theory respecting the operation of mineral manure. davy observes, that "the only substances which can with propriety be called fossile manures, and which are found unmixed with the remains of any organized beings, are certain alkaline earths, or alkalies, and their combinations." if he intends to limit the term to those bodies only which find their way into the structure of plants, his definition may be correct; but i am inclined to take a much wider view of the subject, and to include all those mineral substances which promote vegetation by modifying the texture of the soil:--but of this hereafter. lime, not only from its importance, but from the controversies which it has occasioned, ranks first in the list of mineral manures. that disputes concerning the uses of lime and its carbonate, should have long existed, and be still continued amongst a class of persons who, whatever may be their practical knowledge, are not acquainted with the composition of the substances about which they differ, is certainly by no means extraordinary. davy, therefore, very properly introduces the subject, by a description of the nature and qualities of these bodies, and by marking the distinctions between quicklime and its carbonate. the substance commonly known by the name of _limestone_ is a compound of lime and carbonic acid, associated generally with other earthy bodies, the nature and proportions of which vary in different species. "when a limestone does not copiously effervesce in acids, and is sufficiently hard to scratch glass, it contains siliceous, and probably aluminous earth. when it is deep brown or red, or strongly coloured of any of the shades of brown or yellow, it contains oxide of iron; when it is not sufficiently hard to scratch glass, but effervesces slowly, and makes the dilute nitric acid in which it effervesces milky, it contains magnesia; and when it is black, and emits a fetid smell if rubbed, it contains coally or bituminous matter." as the agricultural value of limestone is materially modified by the substances with which it may be associated, their analysis becomes an object of much importance, and the author has accordingly proposed a simple method of effecting it. before any opinion can be formed of the manner in which these different ingredients operate, it is necessary that the action of the pure calcareous element as a manure should be thoroughly understood. in its caustic state, whether used in powder, or dissolved in water, lime is injurious to plants. davy informs us that he has, in several instances, killed grass by watering it with lime water; but in its combination with carbonic acid, it is an useful ingredient in soils. when newly-burnt lime is exposed to the atmosphere, it soon falls into powder, from uniting with the moisture of the air; and the same effect is immediately produced by throwing water upon it, when it heats violently, and the water disappears: in this state it is commonly called _slacked_ lime: chemists have named it the _hydrat_ of lime; and when this hydrat becomes a carbonate, by long exposure to the air, its water is in part expelled, and the carbonic acid takes its place. lime, whether freshly burnt, or slacked, acts powerfully on moist fibrous vegetable matters, and forms with them a compost, of which a part is usually soluble in water. by this operation, it renders inert vegetable matter active; and as charcoal and oxygen (the elements of carbonic acid) abound in vegetables, it is itself, at the same time, converted into a carbonate. but limestone simply powdered, marls, or chalks, do not thus act on vegetable matter; and hence the operation of quicklime and mild lime depends on principles altogether different. quicklime acts on any hard vegetable matter, so as to render it more readily soluble; the mild limes, or carbonates, act only by improving the texture of the soil, or by supplying a due proportion of calcareous matter: thus almost all soils which do not effervesce with acids, are improved by mild lime and sand, more than clays. i apprehend that it is upon this principle the application of shelly sand proves beneficial in cornwall, although i have ascertained that, on some occasions, its value depends upon its chemical action upon mineral bodies in the soil. soils abounding in soluble vegetable manures are injured by quicklime, as it tends to decompose their soluble matters, or to form with them compounds less soluble than the pure vegetable substance. with animal manures, it is equally exceptionable, unless indeed they be too rich, or it becomes necessary to prevent noxious effluvia: for since it decomposes them, it destroys their efficacy, and tends to render the extractive matter insoluble. the limestones containing alumina and silex are less fitted for the purposes of manure than pure limestones; but the lime formed from them has no noxious quality. such stones are less efficacious, merely because they furnish a smaller quantity of quicklime. those, however, that contain magnesia, if indiscreetly used, may be very detrimental. it had been long known to farmers in the neighbourhood of doncaster, that lime made from a certain limestone, when applied to the land, often injured the crops considerably. mr. tennant discovered that this limestone contained magnesia; and on mixing some calcined magnesia with soil, in which he sowed different seeds, he found that they either died, or very imperfectly vegetated; and with great justice and ingenuity, he referred the bad effects of the peculiar limestone to the magnesian earth it contained. in prosecuting the enquiry, davy however ascertained that there were cases in which this magnesian lime was used with good effect,--in small quantities, for example, on rich land: and during his chemical consideration of the question, he was led to the following satisfactory solution. "magnesia has a much weaker attraction for carbonic acid than lime, and will remain in the state of caustic or calcined magnesia for many months, though exposed to the air; and as long as any caustic lime remains, the magnesia cannot be combined with carbonic acid, for lime instantly attracts carbonic acid from magnesia. when therefore a magnesian limestone is burnt, the magnesia is deprived of its carbonic acid much sooner than the lime, and in this state it is a poison to plants. that more magnesian lime may be used upon rich soils,[ ] seems to be owing to the circumstance, that the decomposition of the manure in them supplies carbonic acid, and thus converts it into a mild carbonate. besides being used in the forms of lime and carbonate of lime, calcareous matter is applied for the purposes of agriculture in other combinations. the principal body of this kind is _gypsum,_ or sulphate of lime; respecting the uses and operation of which very discordant opinions have been formed." [ ] these facts have been confirmed by agriculturists, who could not possibly have had any favourite theory to support. dr. fenwick tells us, (essays on calcareous manures, p. . ,) that in the county of durham, the farmers always distinguish between _hot_ and _mild_ limes. they never apply the former to exhausted lands, or to any soil that has been long under a course of tillage, unless it be very deep and rich. in peaty soils, and in new, sour, and wild lands, the _hot_ limes, on the contrary, are preferred to the _mild_ ones. dr. fenwick made some experiments to ascertain the cause of the differences between these varieties of lime; and though he failed to discover that by analysis which mr. tennant subsequently ascertained, he nevertheless arrived at a just conclusion by simple observation; and was led to believe, that "what farmers term _hot_ limes, are such as re-absorb their fixed air more slowly, and therefore continue longer to exert the peculiar action of quicklime." its beneficial operation has been referred to two causes, viz. to its power of attracting moisture from the air, or to its assisting the putrefaction of animal substances; but davy has shown by experiments that neither of these theories can be supported by facts. the most extraordinary circumstance perhaps connected with the history of this mineral manure, is the very opposite opinions which have been formed respecting its value. in this country, although there are various testimonies in its favour, it has never been employed with the signal success which marked its adoption in america, and which was so palpable and extraordinary as at once to have ensured its universal introduction. i was some years since assured by mr. maclure of philadelphia, that whenever any doubt or hesitation betrayed itself with respect to its fertilizing agency, it was only necessary to sprinkle a small quantity in a meadow, to satisfy the most sceptical; and that this was usually done in the form of letters or characters, which in a short time became so much more luxuriant than the surrounding grass, as to be visible at a considerable distance. it is, i understand, chiefly applied to grass lands as a _top-dressing_; and the american farmers[ ] explain its operation upon its solubility in water, and its consequent absorption by the roots of the grass. davy, in examining the ashes of sainfoin, clover, and rye-grass, which had grown in soils manured by gypsum, found considerable quantities of that substance; and he thinks it probable that it was intimately connected with their woody fibre. he attempts to explain the reason why the application of gypsum is not generally efficacious, by supposing that most of the cultivated soils may already contain it in sufficient quantities for the use of the grasses. i strongly suspect, however, that it will be hereafter discovered to depend upon the nature of the soil in its hygrometric relations. from the facts already recorded, it would appear that it never answers near the sea, nor in wet lands. in consequence of its solubility, it is enabled to penetrate and pervade the whole vegetable structure; and the experiments of davy have proved its presence in the ashes of plants exposed to its operation, and have rendered it probable that it enters into union with their woody fibre, by which the density of their textures will be increased, and consequently the evaporation from their leaves diminished; i am from such considerations induced to think that gypsum does not act by effecting any chemical change in the soil, but solely by diminishing the plants evaporation. this idea seems to be borne out by the evidence furnished by the different circumstances attending the operation of this manure: we find, for example, that succulent vegetables, planted on dry soils, are those which are principally benefited by its application, and that the various grasses so manured retain their verdure, even in the dryest season and on the most arid lands; at the same time, we find that these crops, especially clover, acquire a proportionate increase in the density of their fibres, that is to say, that they become much more rank and stubborn, and often to such a degree does this take place, that in america, where its effects are best understood, sheep not uncommonly refuse to feed upon them. upon the same principle we find that, under circumstances or in situations where the evaporation of a plant is provided for by a constant supply of moisture, the effects of gypsum cease to be apparent. [ ] when this substance was first introduced into america, which is nearly forty years since, it was imported from the quarries of montmartre, and in such request was it, that a bushel of wheat was usually given for the same measure of gypsum: it is now, i believe, obtained from nova scotia; i have not heard that it has been found within the states. it may perhaps serve to convey some idea of the extent to which it has been applied, when i state, that mr. maclure assured me that not less than three hundred vessels are constantly employed in the traffic, and that in philadelphia twenty merchants, at least, are engaged in supplying the demand for it. its efficacy appears to be considerably increased by applying it in a minute state of division; and a want of attention to this circumstance may possibly have been one of the causes which have rendered its advantages less conspicuous in england. in america, three or four hundred mills, of a peculiar construction, have been erected in different parts for the purpose of grinding it. davy hints at a process by which gypsum may be formed in a soil containing sulphate of iron, by the action of calcareous manure,[ ] and which was first pointed out by dr. pearson. i can confirm this statement by the results of experiments i formerly made in cornwall, where soil containing this salt of iron had been manured by shelly sand. [ ] gypsum is readily produced by the admixture of decomposing pyrites and calcareous matter: in proof of which the mineralogist can produce specimens of oyster shells studded with crystals of selenite from shotover; and alum from the _aluminous shale_ at the hurlet mine near glasgow. in pursuing his enquiry into the efficacy of mineral manure, davy proceeds to investigate the efficacy of the fixed alkalies, and observes that their general tendency is to give solubility to vegetable matters, and in this way to render carbonaceous and other substances capable of being taken up by the tubes in the radical fibres of plants. the vegetable alkali has likewise a strong attraction for water, and even in small quantities may tend to give a due degree of moisture to the soil, or to other manures. he considers that pure salt may act, like gypsum, phosphate of lime, and the alkalies, by entering into the composition of the plant. upon the subject of salt, however, his remarks are very meagre and unsatisfactory: at the time he composed his lecture, the subject had not excited that public attention which the writings of mr. parkes, sir thomas bernard, and others, have since awakened. had our philosopher undertaken the agricultural survey of cornwall, his lecture on mineral manure must have been very considerably extended. he would have learnt that various rocks reduced to small fragments, are commonly applied as dressing; he would have explained the cause of the fertility so generally associated with hornblende rocks;--he would have speculated upon the influence of iron in giving fruitfulness; and above all, he would have taught the agriculturist the scientific use of calcareous sand, by pointing out the description of lands which are most likely to be benefited by its application. the eighth lecture concludes the subject of the chemistry of agriculture, by establishing the theory of the operation of burning lands. he considers the process to be useful in rendering the soil less compact, and less tenacious and retentive of moisture; and that, when properly applied, it is capable of converting a matter that was stiff, damp, and cold, into one powdery, dry, and warm, and much more proper as a bed for vegetable life. he states the great objection made by speculative chemists to paring and burning, to be the unavoidable destruction of vegetable and animal matter, or the manure of the soil; but he considers that, in those cases in which the texture of its earthy ingredients is permanently improved, there is more than a compensation for so temporary a disadvantage; and that in some soils, where there is an excess of inert vegetable matter, the destruction of it must be beneficial, and that the carbonaceous matter remaining in the ashes may be more useful to the crop than the vegetable fibre from which it was produced. in this view of the subject it is evident, that all poor siliceous sands must be injured by the operation; "and here," says davy, "practice is found to accord with theory. mr. arthur young, in his essay on manures, states, 'that he found burning injure sand;' and the operation is never performed by good agriculturists upon siliceous sandy soils, after they have been once brought into cultivation. an intelligent farmer in mount's bay told me, that he had pared and burned a small field several years ago, which he had not been able to bring again into good condition. i examined the spot,--the grass was very poor and scanty, and the soil an arid siliceous sand." _irrigation_, or _watering land_, is a practice, he observes, which at first view appears the reverse of torrefaction; and, in general, the operation of water in nature is to bring earthy substances into an extreme state of division. but in the artificial watering of meadows, the beneficial effects may depend upon many different causes, some chemical, some mechanical. it may act as a simple supply of moisture to the roots, or it may carry into the soil foreign matter, or diffuse that which exists in it more equally through its substance. he concludes with some valuable scientific observations upon the process of _fallowing_, by which he attempts to correct the prejudices which have existed with regard to its benefits. he points out, on the other hand, the great advantages of the convertible system of husbandry, by which the whole of the manure is employed; and those parts of it which are not fitted for one crop, remain as nourishment for another. these views he illustrates by a reference to the course of crops adopted by mr. coke, in which "the turnip is the first in the order of succession; and this crop is manured with recent dung, which immediately affords sufficient soluble matter for its nourishment; and the heat produced in fermentation assists the germination of the seed and the growth of the plant. after turnips, barley with grass seeds is sown; and the land having been little exhausted by the turnip crop, affords the soluble parts of the decomposing manure to the grain. the grasses, rye-grass, and clover remain, which derive a small part only of their organized matter from the soil, and probably consume the gypsum in the manure which would be useless to other crops; these plants likewise, by their large system of leaves, absorb a considerable quantity of nourishment from the atmosphere; and when ploughed in at the end of two years, the decay of their roots and leaves affords manure for the wheat crop; and at this period of the course, the woody fibre of the farm-yard manure, which contains the phosphate of lime and the other difficultly soluble parts, is broken down; and as soon as the most exhausting crop is taken, recent manure is again supplied." at the end of his system is added an appendix, containing "an account of the results of experiments on the produce and nutritive qualities of the grasses and other plants used as the food of animals; instituted by john duke of bedford." but as these experiments do not admit either of abridgement or analysis, the reader must refer to the original source for information. i shall conclude this long, and, i fear, somewhat tedious review, with the animated appeal so earnestly addressed by the illustrious author to the philosophical readers of his work. "i trust that the enquiry will be pursued by others; and that in proportion as chemical philosophy advances towards perfection, it will afford new aids to agriculture: there are sufficient motives connected both with pleasure and profit, to encourage ingenious men to pursue this new path of investigation. science cannot long be despised by any persons as the mere speculation of theorists, but must soon be considered by all ranks of men in its true point of view, as the refinement of common sense guided by experience, gradually substituting sound and rational principles for vague popular prejudices. "the soil offers inexhaustible resources, which, when properly appreciated and employed, must increase our wealth, our population, and our physical strength. "we possess advantages in the use of machinery, and the division of labour, belonging to no other nation. and the same energy of character, the same extent of resources, which have always distinguished the people of the british islands, and made them excel in arms, commerce, letters, and philosophy, apply with the happiest effects to the improvement of the cultivation of the earth. nothing is impossible to labour, aided by ingenuity. the true objects of the agriculturist are likewise those of the patriot. men value most what they have gained with effort; a just confidence in their own powers results from success; they love their country better, because they have seen it improved by their own talents and industry; and they identify with their interests the existence of those institutions which have afforded them security, independence, and the multiplied enjoyments of civilized life." end of the first volume. london: printed by samuel bentley, dorset street, fleet street. transcriber's note: minor spelling and punctuation inconsistencies, and hyphenated words, have been harmonized. the formatting of the letters has been regularized. every effort to decipher the hand written letter by sir humphry davy has been made, however, there are no guarantees that it is correct.