NATIONAL LIBRARY OF MEDICINE Washington Founded 1836 U. S. Department of Health, Education, and Welfare Public Health Service THE DOCTRINE OF PHLOGISTON ESTABLISHED, AND THAT OF 1 the COMPOSITION of WATER REFUTED. THI SECOND EDITION WITH ADDITIONS. i B* JOSEPH PRIESTLEY, L. L. D. F. R. S. &c. Sed revocare gradum, Hie labor, hoc opus est, Virgil; NORTHUMBERLAND: PRINTED FOR P. BYRNE, No. 72, C&emut Street, Philadelphia, BY ANDREW KENNEDY, Framkliks-Head, Queen Street, 1803. y ♦ \ O "i ■ VI 9" ■: A ,• ft I '■• % m A ■ ±sS THI DEDICATION. TO SAMUEL GALTON, Esq. JiEAR SIR, XT ERMIT me to endeavour to per- petuate, as far as I can the remembrance of your valuable friendmip to me (as well as that of Mrs. Galton to my wile) which has continued without interruption from the time that we became ac- quainted on my fettlement at Birmingham. The interviews that we hive had at ihe lunar Society, and on other occafions, I now look back upon with peculiar fatisfa&ion, tho* mixed with regret* There is no lunar fociety to which I can commu- nicate my obfervations, and from which I can re- ceive light in return, in this place, a 2 At xv The DEDICATION. At my time of life, however, I could not ex- pect to enjoy any fociety in this world much long- er. Others, alfo, of our members, muft now be looking forward, as I do, to a Mate of greater fecu- ^ rity and permanency jthan_the prefent; where no riots will feparate us again, and where we lfiaTt, i doubt not, refume our pleafing purfuits, and our fpeculations concerning the wonderful fyMem of which we are a part, and with more advantage and fatisfa&ion than ever. * There orily can I have afcy certain profpecl; of meeting with any of you. But the confident ex- pectation that I haye of .meeting my philosophical and chriftian friends again, is a lource of confola- tion and pleafing reflection in my prefent ftateoi exile from them that is invaluable. £ Thb,ncompared to this,'the moil- important of all fubje&s, I feel but little inftereft in the quefti- on which; in this treatife, I brjtfj* Once more'be- "rore the Public ; it is a great {atisfa&ioii to me, that I have the fahction of my friends of the lunar fociety at Birmingham, for the doctrine maintain- ed in this trcatife ; and notwithftahding the great name's among the advocates for the new fyflem in ' other countries, as well as in France, there are no where to be loiind men of more knowledge, faga- i gacity * Since this was written I have heard that one of the members of this fociety, viz. Dr. Withering,"!* dead. The DEDICATION. gacity, and cool obfervation, than in your body. Nd perfon needs to be afhamed of being in an er- ror in fuch company. Allure them all, that I fhall ever think of them with particular efteem and affection ; and if, con- trary to my prefent expectations, there mould be an interval of Jteace in this moft difaftrous war, while I am able to bear the voyage, I flatter my- felf with the profpecl of paying a vifit to my friends in England ; and then I fhall certainly take the firft opportunity of attending one more of your meetings. If providence fhould order otherwife, Adieu till we meet in more favourable circum- ftances than we can ever do at Birmingham. With the greateft efteem and affection I am, Dear Sir, Your* fincerely. J. PRIESTLEY. Northumberland, October 20, j 803. The PREFACE. n JL-/ESIROTJS of bringing the important controverfy concerningphlogiston to a fair decifion, I fome years ago, made many experiments with that view, the refult of which appeared to myfelf favourable to the difcarded hypothefis. Since my removal to Ame- rica, where, after a long interruption of my purfuits, I found myfelf in clrcumflances tolerably favourable to the refumptipn pf them, one of the firfl things that I did was to continue the fame refearch, and many of thefe new'experiments being favourable to the old the- ory, I endeavoured in feveral publications, efpecially in the Medical Repository printed at New-York, to pro- mote the fame difcuffion ; fome of the articles being written in direct defence of what 1 had advanced, and others in reply to objections ; and having new, I ima^ £ipf> The PREFACE, vii gine, heard all that can be urged in favour of the new theory, from its ablell advocates, both here and in Eu- rope, and thinking it far from being fuflicient for its fupport, I repuhlifh in this work all that I think of im- portance in the former publications, and prefent it to the public as a demonstration of the doctrine of phlogis- ton, and a complete refutation of that of the composition of water. For, after the beft attention that I am able to give to the fubject, fuch it appears to me. The refutation of a fallacious hypothefis, efpecialJy one that is fo fundamental as this, cannot but be of great Importance to the future progrefs of fcienee. It is like taking dowu a falfe light which misleads the mariner, and removing a great obftacle in the path cf true know- ledge. The longer fuch an hypothefis has been receiv- ed, and the more numerous and able are its advocates, the greater fervice is rendered to fcicnce by the refuta- tion. And there is not perhaps any example of a philo- fophical hypothecs, fince the revival of true fcienee, more generally received, or maintained by perfons of greater eminence, than this of the rejection of phlogis- ton. In this country I have not heard of a fingle ad- vocate for phlogifton. In England they are very few, and none of them have written anything on the. fub- ject. In France they arc dill fewer, and in Germany I hear of no names befides thofe of Crell, \7eflrumo, Gmelin, and Ma;/M\ Noperfon, however, need to be afliaraed of avowing an c; inion which has the fanction of fuch names as (lit fe. L'ut what r,v.y of them may L.t.t written in referee of pli'n-'fler ]-, urI-'-\'Wii to me; a 4 fo viii The PREFACE. fo that uW we are engaged in the fame caufe, we are unable to give the leaft afliftance to each other. Removed as I now am to fo great a diftance from the great theatre of philosophical purfuit, and out of the way of early intelligence (our communications with Europe being alfo farther interrupted in the prefent un- fortunate ftate of war) I neceffarily labour under vari- ous and great difadvantages. 1 am thankful, however, to a kintl providence for the quiet that I here enjoy in this remote fjtuation, and for fuch means of profecuting my fludies, as, coniidering the ftate of the country, are very ample.* And I hope that, confidering my advanc- ed age, I {hall be thought to have been tolerably aflidu- ous in making ufe of them. But my philofophical friends muft excufe me if^ without neglecting natural fcienee, I give a decided preference to theological fludies, and if here, as in Eu- rope, I give the greatefl part of my time to them. They are * To the account of my reasons for leaving England I prefixed a motto from Petrarch, whose Latin works, and especially his Letters, often amuse and interest me. It was from his address to his patron the Cardinal of Colonna. C. Quo fugis ? Expecta. Liceat condisee:e causas Dissiclii. Tunostra, puer, viisi fallor, i mabas Pascua. P. Parcc, Parens, damnare tiuim—Tibi lxtior annis, Tunc animus fuerat. Kun'cintrac ahllis, aspcr. I nay now apply to myself ulu: he addressed to the bishop of Ca- bassole when he was at Vr.i.cl;.sc, absent frcm his native country Italy. Exul ab Ita.ia, fi.i.i-, ch'.lll.us actus, Hue subii, partimque vok-rs, partimque coactus. Hie nemus, hie amnes, his ocia ruris amceui. Sed fidi c smites ahsv.nt, vuhusque sereni. Hoc juvat, hec cracitt. Nihil illis dulce rcmctis. The^PREFACE, i Sc- are unqueftionably of unfpeakataty more importance to men, as beings deftined for immortality ; and I apply N myfelf with fo great fatisfaction to the ijfcudy of nature, not fo much on account of the advantage we derive from it at prefent, tho} this is very confiderable, as from its being a delightful field of {peculation barely open* ing to us here, and to be refumed with far greater ad- _ vantage in a future ftate. No difcovery in philofophy bears any proportion in real value to that of bringing life and immortality to light, which is completely effected in the Gofpel, and no where elfe. None of our experiments, or obferva- tions on the courfe of nature, could have given us the leaft glimpfe of this. But the evidence of this great truth, tho' of the moft fatisfactory kind, not being that of sense, but requiring attention and reflection, perfons much engaged in the bufinefs of the world, and even in literary an- fcienti- fical purfuits, are not always convinced by it. It alfo requires a candid and well difpofed mind, and there- fore philofophers (who have their prejudices as well as other men) are not always chriftians. Among thofe of this clafs, I am however, happy in being able to rank not a few, who would do honour to any caufe ; and the number of truly philosophical chriftians, I am well ptr- fuaded, will in due time inert::fe. As Paul faid to king Agrippa(who faid that he had ': almoft perfuadtd him " to be a chriftian") that " he wifhed that both he, end " all who then heard him, were both almoft, and ah:>- " gether, fuch a, he himfclfwas, except his bonds;" . Co there is no greater happinefs that I can wiih to all niv X The PREFACE: my philofophical friends, than that, with refpect to re- ligion and their future profpects, they were what I am, without the calumnies, and the ftill more ferious inju- ries, to which I have been expofed. Without a view to this future fituation, all our pur- fuits appear to me to have little in them that is inter- refting, efpecially in the decline of life, and the near profpect of death, which, if it put a period to our exis- tence, involves every thing in cverlafting darknefs, leaving us uncertain whether even the world itfelf, and the whole race of man, as well as all other animals, mav not be doomed to deftruction. How gloomy is this profpect, and how dead and indifferent does it render a reflecting mind to every great purfuit ! How thankful, then, ought we to be for an affurance of an endlefs ftate of exiftence, and in circumftances infinitely more favourable than the prefent. The evi- dence of this great doclrine (in comparifon with which every other inquiry is as nothing) is furely worthy of our moftafiiduous examination, infinitely more fo than a titiVto an eftate, or a claim to a kingdom in this world, which no wife man would be thought juftifiable in ne- glecting. This being perhaps the laft time that I may have an opportunity of addrefling myfelf to my philofophical friends, who, I am concerned to perceive, are generally unbelievers in revelation, I would make it my dying re- queft, proceeding from the moft Tmcere good will to them, to attend to this fuhject, efpecially to what I too1: the liberty to urge in the Frcfcrrto the lixth volume ci »iy rJbr.rri-ath:v: on air, which was reprinted inthenevr edit: or. The PREFACE xi edition of that work in three volumes, and alfo to my Letters to the philosophers and politicians of France on the subject of religion, my Letters to a philosophical un- believer, and my other works in defence of revelation. Independently of the confideration of the infinitely fuperior importance of the fubject, religion will give a double relifh to philofophical purfuits, and will thereby contribute to their fuccefs. It is only a wretched fuper- ftition, and not religion, that draws men's attention from natural fcienee, or with any other view drives men into retirement, and excludes them from any active and ufeful purfuits, On the contrary, it tends to infpire men with increafed activity, and imparts incrcafing fa- tisfaction and animation in every proper and laudable exertion. Of this I think I may fay I have exhibited an example myfelf. My numerous publications v,Hi fhev/ that from early life I have given the greateft part of my time to theological ftudies, and yet few have been more afliduous in phyfical inquiries fince 1 have had the means of doing it. Do not then fay that religion makes men idle, or bufy to no ufeful purpofe. Call this, if you pleafe,the talkativenefs of age ; but believe it to proceed from a zeal in the btft of caufes, and fmcere good will to yourfelves. For I find that I have infenfibly got into a direct addrefs in the form of a dedication, rather than that of a Preface. With this, however, I conclude Farewell, and may we meet where. our prefent doubts will be removed, and where we fhall m^ke more rapid advances in knowledge, without th^.t envy and jealoufv, from which rvilcfophers are no more exempt than other men, and which, tho' :t has en exe client The PREFACE. excellent effect in making men cautious, and even ar- dent in their purfuits, from a view to the reputation they hope to acquire by their difcoveries, too often makes their purfuits the fource of more pain than plea- fureto them. Hereafter, we fhall, 1 doubt not, bp even more actively employed, ancl more happy in confe- quence of it, from better motives. 1 (hall clofe this Preface with the Letter I addreff- cd to the advocates Jbr the new theory in France in the firft pamphlet I publifhed in anfwer to them, and alfo a fecond, which I addrefs to ^hem in the prefeJjt ftate of the. controverfy. To Messrs. Berthollet, De la Place, Monge, Mor- veau, Fourcrcy, and Hasscnfratz, the surviving answerers of Mr. Kir wan. Gentlemen, rl AV1NG drawn up a fliort defence of the doctrine of phlogiston, I take the liberty of in- feribing it to you, as the principal advocates for the AniiphlogiPiic theory. My view in this is to draw your attention cue t more to the fubject, and 1 re que ft the favour The PREFACE xiii favour o*" an anfwer to my objections. I hope I am not wanting in a proper deference to the opinion of men fo juftly eminent as yourfelves* and your friends in France, and alfo that of great numbers in England, and wherever chemiftry is known, who have adopted your hypothefis. But you will agree with me, that no man ought to furrenderhis own judgment to any mere authority, however refpectable. •Otherwife, your own fyftem would never have been advanced. As you would not, I am perfuaded, have vo ure'gn to referable that of Robespierre, few as we are who re- main difaffectedi we hope you had rather gain us ' by perfuafion than filence us by power. And tho' we ^are all apt to flatter ourfelves, We hope we are as will- ing to be influenced by the former, as We are inflexible to the latter. If y6u gain as muvh by your anfvver to me, as you did by that to Mr. Kir wan, your power will be univerfally eftablifhed, and there will be no Vendee ib. your dominions. Differing as we do in this refpect, we all agree in ©ur wiftles for the prevalance of truth, and alfo ofpeace, which is wanted as much for the interefts of philofo- phy, as thofe of humanity. And on this account I ear- neflly wifh fuccefs to the liberty and profperity of France, which did me the honour to adopt me when I was perfecuted and rejected in my native country. With great fatisfaction, therefore, I fuhferibe myfelf Your fellow-citizen, JOSEPH PRIESTLEY. Northumberland in America, June 13th, 1795. A The PREFACE. A second Lctttr to the same. Gentlemen, _/"\_BOUT three years ago I took the liberty to requeft vour reconfideration of the doctrine of phlogiston, which you had long difcarded. A very refpectable advocate of your fyftem, Mr. Adet, being then in this country, hi replied to my defence of it, and at length I have juft received what may be called your definitive anfwer, in the Report of Messrs. Ber- thollet and Fourcroy on the merits of our performanc- es, in the 26th volume of the Annales de Chymie, in which you confider me as fupporting a fyftem un pen chancelante. As a friend of the weak, I have, indeed endeavoured to give it a little affiftar.ce ; and as there is no giving ftrength to one of the oppofite fyftems without taking it from the other, I prefume that yours is now in the fame fituation, calling to you for all the fupport that you can give to it. On the opening of this controverfy I told Mr. Adet that 1 fhouldhave greater pride in acknowledging my- felf convinced, if I faw reafon fo to be, than in victory, and fhould furrender my arms with pleafure. I was fincere in that declaration ; and certainly the conqueft of a man's prejudices is more honourable to him than the difcovery, or the moft fuccelsful defence, of any truth. The PREFACE. xv truth* This, however, I mull, for the prefent at leaft, decline, and leave it to you ; contenting myfelf with the ( inferior praife of confirming the hypothefis for which 1 have contended. If, from the politenefs habitual to Frenchmen, you Ihould decline this honour, thinking my claim to it better founded than yours, I may here- after be induced to receive it; but for the prefent, yielding to you a palm more glorious than that of any victory, and trufting that your political revolution will be more (table than this chemical one, I am, with the greateft refpect, I Gentlemen, Your fellow-citizen, J. PRIESTLEY. Northumberland in Amerka, Oct. 22,1803. . < i'.y.\. .'■;.;;.: -.i:Ji..., • •■.., _ • : -,.-..■ j [jrr. ,-<-l, ^e-i-oqvrl • ■; 31".;. , • i.u.-M v. . . ' ... ;;: tfiiuq . •;; • ,;i...< .'• ■' .;. '■.. . • •-: . .ij.tiil'> t. iCi-v?:■ i.'r': :* ;; : i ,..* .;:: «Jar>foiq . • i . . . • d -tujij; v'*~,u.The PREFACE i..'.7 I. .... :c ••.:.... . . ts- > ft' ..'' eld; :-j TO THE SECOND EDITION. t-' - T-:■_»•■' -I'/i iUoY HE firft edition of this pamphlet was pub- lifhed in the beginning of the year 1800, and it com- prized the fabftance of fevferal prooeedi*^ publications on the fame fubject, after I had heard the obfervations that had been made on them by the chemifts in Ame- rica and alfo thofe in France, the authors of the fyftem that I controvert. I wrote with a view to promote the difcufiion of a queftion that is acknowledged to be of very great importance in chemiftry, and to which I had not been able to engage much attention ; tho' fome, and the moft material, of my objections had been before the public as foon as it was generally known, and it is now nearly twenty years fince this new theory was advanced. At length, however, I found that 1 had fo far fuc- eeeded, that Mr. Cruikfhank replied to my pamphlet, tho' The PREFACE. xvii tho' to not more than to an argument from one of my experiments, and that the principle on which he replied is greatly approved by the advocates for the new che- miftryin France. i To Mr- Cruikfhank's animadverfions (publifhed in Mr. Nicholson's Journal Quarto vol. 5, p. l) I replied, and on the twenty fecond of the fame month, viz. March 1802, in which my anfwer was publiQied he dates his reply to it, written with an air of the moft perfect per- fuafion of his fuperiority in the argument. Immedi- ately on the receipt of this, which (living as 1 do at a great diftance and the communication by fea efpecially in time of war being flow) could not be very early, I wrote my reply, and it was publilhed by Mr. Nichol- fon in his Journal for Feb. 1803. In this I exprefsed great fatisfaction in the difcuffion being entered upon by a perfon fo well qualified to do jufticeto his argument as Mr. Cruiklhank is univerfal- ly acknowledged to be, and I invited him to difcufs the other articles of the difference between the two fyftems, feveral of which are of more importance than that which he undertook to canvafs. Ready as he was to reply before, I fully expected his anfwer in the month following the publication of mine ; but having before me five fucceeding numbers of the Journal, in none of which is there any notice of my laft communication by Mr. Cruiklhank, or any other perfon, and there being a demand for a new edition of this pamphlet, I have not thought it neceffary to wait any longer ; and my anfwer to his objections, with fome little addition, will be found in the fourth fection. Still, b however xviii The PREFACE. however, if I hear any thing farther on the fubject, from Mr. Cruiklhank, or any othtr chemift of note, in England or elfewhere, I fhall not fail to notice it m fome way or other ; and I hope I am not thought to be fomuch attached to any opinions I have advanced, but that I fhall frankly acknowledge any miftake that I may have inadvertently fallen into. Of this, however, our readers will be the proper judges. I refer the reader to feveral judicious and well con- ducted experimehts of Dr. Woodhoufe, Profeffor of cbemiftry in the univerfity of Philadelphia, in an Ap- pendix to the American edition of Parkinson's Chemical pocket book, on the calces of feveral of the metals, the refults of which are manifeftly inconfiftent with the principle of one part of the new theory, which the in- genious experimenter confequently abandons. In my opinion the abandonment of any of its parts muft lead to that of the whole, all the parts of it having the clofeft connection with each other j but the perception, and acknowledgment of this, muft be the work of time and reflection. Dr. Woodhoufe clearly proves that the air that is procured from charcoal and water will by no means warrant the conclufion that Mr. Lavoifier draws from it, and that my inference from it is juft, pi 209. He thews that water is the principal agent in producing part of the inflammable and fixed air that is got from charcoal and the calces of feveral of the metals, efpeci- ally that from finery cinder ; that " if the oxvgen "in them was the fole agent, the inflammable air pro- " cured from them inthefe circumftances could not be " obtained The PREFACE; xk « obtained; and that the flowers, or white oxide of zinc, " frequently affording inflammable and no fixed air, " whenfubjectedto heat with coal, cannot be account- « ed for by the new doctrine." p*216. But if the calces of thefe metals, efpecially that of iron, be not perfect oxides, the proof of the decomposi- tion of-water muft fall to the ground ; and there, I am now pretty confident, it lies, and that all efforts to raife it will be as ineffe&ual as thofe of Mr. Cruiklhank. My labours of every kind now rapidly drawing to a clofe, I propofe foon to reprint feveral articles of ob- fervations and experiments that are publifhed in the Transactions of the Philosophical Society in Philadelphia, in Mr. Nicholson's Journal, and the Medical Repository of New York, and a few other articles not yet publifh- ed. 1 hefe, together with this tract in defence of the doctrine of phlogifton, will make a feventh volume of my philofophical writings, or a fourth to thofe that are abridged and methodifed in three, and they complete a\l that I have been able to do for the advancement of natural fcienee. Confidering the many, and fometimes long, interrup- tions of my labours, efpecially in confequence of remo- vals, as from Warrington, where I began my experi- ments in electricity, to Leeds, where I began thofe on the different kinds of air ; from Leeds to Wiltfhire, when Ifpent the winters in London, and during which time I accompanied the Tlarquis of Lansdown in atour through Flanders, Holland, part of Germany, and France ; from Wiltfhire to Birmingham, where all my philofophical xx The PREFACE: philofophical apparatus was deflroyed ; from Burning- hanrto 'Hackney,'where my ftay was too fliort to admit ofm)' doing much bufinefs of any'kind i and lafllv from Hackney to this country ; and here, fo often from one houfe to another (the inconvenience and lofs of time attending which only an experimenter cat! form an iclea of) together with many difadvantages underwhich Inowi neceffarily labour, where almoft tveiy thing relating • to experimental j hilofophy and cherriftry muft be had from 1'urope ; when, 1 fay, thefe circumftances arc confidered, and that 1 did not (forwant of opportunity) make any orij \ ial experiments till I was near forty, I hope it will be thought that 1 have not been deficient in point of industry j whatever maybe thought of the va- lue of my labouis. ° "' I am truly thankful to the fovereign difpofer of all things, and to thofe friends of fcienee who have defray- cd:the t'Kpei'ces of ri»y laboratory, thatl have been a- ble to do fo much ; and I hope my liberal benefactors will not repent of their generofity. Indeed, the greater part of them are gore Lefoie rue, to a ftate in which I fhall hope to join them, where 1 cm again exprefs my gratitude, and when we may rgain unite cur refpective abilities in the fame pleafing purfuits ; feeirg more of the wifde n and jocdrefs of the great creator, and hav- irg cv.r r.cmiration ;nd devotion excited to a greater height than ever. The it. > . - » The CONTENTS. PACE THE INTRODUCTION, 1 SECTION I. That Metals are compound Substances, and contain Phlogifton, proved jrom the Solution of Iron in the vitriolic and marine Acids, and from fome ether Consider- ations. - r Sect. II. Of Finery Cinder. - 12 Sett. III. Of inflammable Air Jrcm Finery Cinder and Charcoal, - - 21 Sett. I.V. Of Mr. Cruikshanks Hypothesis to account for the Formation of injlammable Air in the Procefs of heating finery Cinder and Charcoal. - - - 27 Sect. V. Of the Calces of Zinc. - 90 Sect. VI. A-runcnts in Favour cf the Doc- trine of F't'rg if!on from fome Circumflances in uhich £ ilpLur is formed, and nitrcus Acid' phlogiflicated. - - 40 Sea. xxii The CONTENTS. i FACE Sect. VII. Of the Calces of Mercury. 43 Sea. VIII. Experiments on heating Manga- nefe in inflammable Air. - - 55 Seft IX. Of the Decomposition of Water 58 Seft. X. An Argument againfl the Decompo- ftion of Water from the different Proportions of the Elements of which it isfuppofed to con- fifl, accdrding to different Experiments. 70 Sea. XI. Of the suppofed Decompojition of Water in the Experiments of Van Trooft- wick and Deiman, in thofe of Mrs. Fulhame, and various other Proceffes. - 74 Sea. XII. Of the Conflitution of Fixed Air 83 Sea. XIII. Of Phlogifticated Air. gi The Conclusion, - - 102 APPENDIX. i.Of.Dr. Mitchill's Attempt to reconcile the two Syflcms. ' - - 105 2. Of the Discovery of the Production of de- phlogiflicatcd Air by the Action of Light on Plants, - - 107 3. Of the Discovery of dephlogiflicated Air. 116 4. Of Mr. Humphry Davy's Efjoys. 117 ERRATA. Page 29 1. 9, after unite, add with, the carbone ---- 41 1. 17, ears* it will, however, be fhewn that it does not always form any u- nion v/ith the inflammable air, but remains mixed with it, fo as to occafion dangerous explofions. Mr. Lavoifier and his affociates obferve (Utepert, p. 300) that when a calx ,s revived in inflammable air more water is found in the veffel than the Weight of the inflammable air that disappears, fo that it could no* have been contained in that air. B2 Ia ao Tki'Doctrine of In this they only refer to my experiments in gefttt.- ral; but as' they fpeak of the Water produced as appear- ing both on the infide of the veffel, and on the furface of the mereurv, it can be no other than the experiment of the revival of iron from finery cinder; and the water that is found in this procefs was never 'Tup'pofed by me tocdme from the little that is contained in the inflam- mable air, but from the much greater quantity contsfinc edrin the cindef. Before I conclude- this feaion concerning finery cinder^ I muft take notice of what Dr. Maclean tOoccm- fidently advances about it. " The Doaor," he fays pP 26, " is certainly rniftaken' in fuppofmg: that finely cin- 14 der;cannot ruft. Mr. Fourcroy fays it rufts" fooneir " than common iron, and every apothecary knows- it '•does To. If the ruft of iron be made red hot in a re- " tort,' a quantity of carbonic acid is direngaged from " it, ahd the iron remains in a ftate of black oxyd. The " ruft therefore is ^carbonate of iron, and muft contain tl all the principles which compofe the black oxyd, and " therefore can contain nothing capable of excluding " that which would convert it into ruft." But, in di>- rea contradiaion to what he afferts, I flill fay that fine- ry cinder is notfubjea to ruft. In England-no ufe hav- ing been made of it before it was attended to by my brother-in-law Mr. John Wilkinfon (one of the moft in- telligent and ficcefsful of all the iron-mafters in that or any other country) but to mend the roads, it has Iain in leaps for years, I may even fay ages, without acquiring the leaft tinge of brown. All my fpeci mens have ever remained free from ruft, and the phyficians, who are alfa Phlogifton eftabji/hcd. 21 alfo apothecaries in this place, affure me they never faw or heard of any fuch thing. They get it from the black- frmths in the form of,scales of iron, and the blackfmhhs fay Jthe hwae. It muft therofore, as I have obferved, be faturated with Tome principle very different from that of the common ruft of iron, and is by no means the fame thing, notwithftanding what Dr. Maclean fays to prove the contrary. If finery cinder be ever converted into ruft, which I have never found to be the cafe, it muft, by fome procefs or other, natural or artificial, have been firft converted into iron, in which cafe it muft lofe much of its weight. i i ■> SECTION III, Of inflammable Air from Finery Cinder and Charcoal. AF inflammable air, or hydrogen, be nothing more than a component part of water, it could never be produced but in circumftances in which either water itfelf, or fomething into which water is known to enter, is prefent. But in my experiments on heating finery B 3 cinder 28 The Doctrine of cinder together with charcoal, inflammable air is pro- duced, though, according to the new theory, no water is concerned. According to this theory, finery cinder, called the oxide of iron, confifts of nothing befides ircn a~u oxygen $ and the charcoal made with ;he greateft degree of heat that can be applied, is equally free from water ; and yet when thefe two fubftanres an mixed together, and expofed to heat, they yield inflammable air in the greateft abundanee. This faa I cannot account for on the principles ^f the new theory ; butnothing is eafier on thofe of the old. For the finery cinder containing water, as one of its component parts, gives it out to any fubftance from which it can receive phlogifton in return. 1 he water, therefore, from the finery cinder uniting with the char- coal makes the inflammable air, at the fame time that part of the phlogifton from the charcoal contributes to revive the iron. Inflammable air, of the very fame kind is procured when (learn is made to pafs over red hot charcoal. Since inflammable air, and in great quantity, is pro- cured in this procefs, the antiphlogiftians are under a neceffity of finding ivater, by the decompofition of which, and in no other way, they fay it is made ; and fome of them find it in the charcoal, and others in the finery cinder. As Dr. Woodhoufe repeated this experiment with peculiar exaantfs, 1 fhall copy his account of it from the Philosophical Transactions of Philadelphia, Vol. iv, p. 464t " An ounce of the fcales of iron, and the fame ** quantity Phlogiston ejlahlifhei. 23 "quantity of charcoal, were reduced to a very fine 11 powder, and expofed feparately in covered crucibles " in an air furnace wellfupphed with fuel for five hours. «' They were then taken out of the fh\, and mixed " while red hot, in a red hot iron mortar, were tirtura- " ted with a red hot peftle, formed of an iron ramrod, " were poured upon a red hot fheet of iron, and inftant. '«ly put into a red hot gun barrel, which was fixed in " one of lewis's black lead furnaces, and which com- " municated with the worm of a refrigeratory, a part i( of a hydropneumatic apparatus. Immediately after '«luting one end of the gun barrel to the worm, one " hundred and forty two ounce meafures of inflamma- " ble air came over in torrents, mixed with one tenth " part of carbonic acid gas." Nothing more could have been done to exclude all water from each of the fubftances previous to their mix- ture ; and yet we immediately find the efivas of water as much as if water itfelf had been emploved infield of the finery cinder, which no doubt, contained it. This experiment I fhould have expefted, might have con- verted the ingenious author of ithimfelf. His expla- nation of it however, is fo unfatisfaaory that I cannot help thinking the confiderationof it will go a great way towards the converfion of others. For he admits that there really is water, and in this great quantity, in the finery cinder. But if we fuppofe finery cinder to contain water, and fo much of it a.> is neceffary to form all the air that is produced in this procefs, both fixed and inflammable, we muft, furely, abandon the moft fundamental princi- B 4 pk 2 4 The Doctrine of pie of the new theory, which absolutely requires water to be decompofed >n palling over hot iron, the oxygen alone remaining in the iron, and the hydrogen efcaping in ;he form of inflammable air ; artd it is only by com- pazine the addition of weight acquired by the iron in this cafe, that the proportion between the oxygen and the hydrogen in the compofitionof water is ascertained. Befides.how can it be fuppofed that water Ihould both be decompofed, and not decompofed, in the fame cir- cumftances ? I o the experiment wi-.h the finery cinder and char- coal Mr. Berthollet objeas, Report, p. 15, that " 1 pro- " bably got more fixed air than inflammable, that the " inflammable air contains much charcoal diffolved in " it, and that in many experiments charcoal appears to " retain water very obftinately." How obflinately charcoal retains, water is eafily af- certained. When water only adheres to any fubftance without entering into it as a conftituent part, a degree of heat capable of converting it into fleam, will always be fufficient to expell it; and the antiphlogiftians have not yet faid that water is an effential part of this carbone. This they fuppofe to be a fimple fubftance; and tho'com- mon charcoal is not pure carbone, they do not pretend to fay that water can be in it except as an extraneous fubftance. Perhaps when they find their theory unpen chanceiante, they may have recourfe to this fupport. Mc firs. Berthollet and Fourcroy, however, fay that (his infl immable air comes from the decompofition of the " water contained in the charcoal, and which they " fay Phlogifton eflablifhed. 25 "■ fay cannot be feparated from it but by forming a new %< combination with it." Annates dt Chymie^ Vol. xxvi, p. 306. But as water is no conftituent part of charcoal, it certainly may be feparated from it by heat, without forming any new combination, or undergoing any de- compofition. If it be the water adhering to the charcoal that is decompofed, and the component parts of this water enter into a new combination with the carbone of it, I afk of what ufeis the finery cinder in the procefs, whichy however, is effential to the fuccefs of it; and why might not the fame heat have the fame effea in decom- pofing this water, without the finery cinder, as well as with it ? I hey do not fay they have any occafion for the oxy~ gen contained in the finery cinder, which, however, leave* it in this procefs ; fince the iron is revived ; and how can they account for the feparation of this oxygen from the iron without the fuppofition of fomething going in to take its place. Heat alone will not effea this. For heat tends to unite, and not to feparate them. In whatever manner thi3 water, adhering to the charcoal, contributes to the formation of inflammable air, Mr. Bertholiethimfelf would fay, that when any particular degree of heat would not make charcoal \ield any more inflammable air, there was no more writer retained in it than the fame degree of heat was able, with its affulance, to decompofe. I>ut after this, by the afliftance of finery cinder, with even a much iefs 13 5 degvte 26 The Doctrine of degree of heat, it yields inflammable air very copioufly, juftas if fteam had been made to pafs over it in that heat; and, judging ftom evident appearances, there cannot be a doubt but that, with a fufficient quantity of finery cinder to fupply it with water, all the phlogif- ton in the charcoal, exclirfive of that which contributed to the revival of the iron, would be converted into in- flammable air. As to the proportion between the fixed and inflam- mable air procured by this procefs, it is about the fame with that procured from charcoal by means of fteam, and will probably vary with the proportion of finery cinder, as that does with more or lefs water. That finery cinder contains nothing but water, ap- pears not only from its enabling charcoal to give out air exaaiy as water would do, but from doing the fame with refpea to terraponderosa aetata, which alfo gives out air by means of water, but not without. I mixed a quantity of this fubftance, reduced to a powder, with pounded finery cinder, and in a gun bar- rel, heated red hot, I got from it fixed air as copioufly as if fteam had palled ever it. 1 here was a considera- ble refiduum of inflammable air from the iron. When 1 firft made this experiment with charcoal and finery cinder, I remember Mr. Watt faid, it was one that the Antiphlogiftians could never reconcile to their hypothefis ; and the^more I confider it, and the objeaions that have been made to it, the more reafon I fee to be of his opinion. SECTION Phlogifton eftablifhed. 27 ,U.. ., . SECTION IV. Of Mr. Cruiklhank's Hypothesis to account for the For" mation of inflammable Air in the Process of healing fnery Cinder and Charcoal. X HE two anfwers to my argument in favour of dv doarine of phlogifton confidered in the preced- ing leotir.n go iincn the proper principle ot the new theory, vz. 'hat whatever is inflammablein any kind of aii muft come from -water. But Zlx. Cruikfhank, fecn-g, no doubt, the impofiibility of finding, or decom- pofinj>. v-jier in the cafe,replies upon a principle intire- 1, n«-w j fince he requires no water at all for the forma- tion of the very great quant:ty of inflammable air that is produced in this procefs. He even maintains that this air, tho' it be evidently as inflammable as that from charcoal and water, is an oxide, cal'ing it the gazeous oxidr of carbone, fuppofing it to be formed by the union of oxyg:n.from the finery cinder and carbor.e in the charcoal, hut in a very circuitous way. For he fuppofes, in the fiift inftance, that a quantity of fixed air is formed by the oxygen of the finery cinder u-;i- i: g with 'carbone in the charcca', unci that tlvs th\c-d a r 28 The Doctrine of air is decompofed by one of its conftituent parts (viz. its oxygen) going back into the finery cinder, and re- converting it into iron ; which iron he fays, by means of heat, decompofes the fixed air, fo that part of its oxygen can unite with the carbone in the charcoal. Thus, he fays, will be formed this gazeous oxide of car- bone without any water. This hypothefis, ftrange as it appeared to me, and even inconfiftent with the moft fundamental principle of the new theory, I found to be quite fatisf&aory to the original authors of this theory in France. One of the moft eminent of them, in converfation with a friend of mine at Paris, faid that " I had kept them for fome " time1 in torture by my objeaions to their fyftem, but " that they were intirely relieved by Mr. C- andhank." In confequence ot this information, 1 have given more attention to this hyppthefisthan many perfons will pro- bably think to have been neceffary, and I have replied by ftating the following objections to it, each of which I cannot help thinking abundantly fuflicient to refute it. 1. Mr. Cruikfhank's hypothefis requires that, in the procefs of heating finery cinder and charcoal, the oxy- gen in the finery cinder ihould quit that fubftance, and unite with carbone in the charcoal, in order to form fix- ed air. Since, however, this fixed air is to be decom- pofed by iron, the oxygen which it has got from the finery cinder muft be feparated from it, and enter into the fame calx again, for there is nothing elfe to receive it. But while the heat continues the fame, I deem A.fo contrarv elF-fts to h* impofiible. If the degree of Phlogifton ifttbtiflkd. *9 of heat that is applied exoel oxygen itt.;o grea$as the difference between the latter ancPthe light inflammable air from metals with acids or water. Dif- ferent as they, may be in other refpe&s, they are all mfammable,. having the common property of unitng with oxygen in a certain degree of heat; in conf quence of Which they are alike the vc.-y : e-yerfe of oxidrs, and muft be claffed'with combustible fubftances, equal y with % fo.l-.-dr and phofphorus. 1 f this kind of air was a real oxide, it would appear to be fo on the decompofition of it, when, to make the refult unexceptionable, the oxygen it contained would tither take the form of dephlogifticated air, or become a component part of fome other fubftance into which oxygen is acknowledged to enter. But this has not been done. When it is decompofed by being fired to- gether with dephlog'liicated air, the fixed air which is the formed comes, I have no doubt, from the oxygen in the dephlogifticated air, and the phlogifton in this fpecies of inflammable air ; the fame being the refult, tho' not in the fame degree, of firing the heavy inflam- mable air from charcoal and water, from oil &c. &c, in- to which it is not pretended that any oxygen enters. it, Phlogifton eftablifhed. a* It, therefore, appears to me to be an abfolute aban- donment ofthe moft fundamental principle of the new theory to call the air from finery cinder and charcoal an oxide. If fubftances be combustible in proportion, to their affinity to oxygen, and their confequent readinefs to unite wTith it, this air, which is inflammable, muft be of this clafs, and therefore the very reverfe of the oxides, which are faturated with oxygen, and incapable of receiving more. 5. If the oxygen, after quitting the finery cinder, entered into it again, it would make it finery cinder as at the firft, or at leaft in fome degree ; whereas the calx is, completely revived in this procefs, the iron fo revived being as foluble in acids as any iron whatever. 6. if the iron ihould be completely revived by the oxygen wholly leaving it, 1 maintain that it could not, by any degree t f heat, decompofe fixed air. For. my experiment with a burning lens, in which it could not be done, is far more unexceptionable than Mr. Cruik- fhank's with bladders and a gun barrel. His objeaion to my procefs. has no weight. It was made with only a very few ounce meaf ires of the air, over mercury, with a lens fixteen inches in diameter, and was contin- ued feveral hours, generally from ten o'clock to one ; fo that no particle of the air could efcape being expofed to a far grc ater degree of heat than could be commu- nicated through a gun barrel. His experiment I hav?. frequently made, both in England and here, but I could never be fatisfied with the refult. The scale which he found upon the iron, I have no doubt, came from moisture in the air, or from the 32 . The Doctrine of the bladders. Indeed, I cannot think that any perfon, conversant as 1 have been, with both th- fe mooes «.♦" o- peratir.fr, ean hefitate in declaring t^is^t the pre trenoj muft be given to mine. 7. Mr. Cruiklhank feems. to think that charcoal can- not contain any oxygen ; but Mr. i ena.it/s fine experi- ment deeifively proves that it does. For where are we to look for the oxygen (which we ail acknowledge to be a component part of fixed air) which is .feparated from the marble; but in the charcoal wfr.ch is produced ? And in that it makes part of a solid substance, and does not take th*e form of air. 8. Since oxygen and all combuftible fubftances unite, and explode together in a certain degree of heat, the oxygen that is expelled from the finery cinder, uniting with earbone from the charcoal when red hoi, muft en- able it to burn, and therefore, in thefe circumftances, there ought to be an explosion, or at leaft a gradual com* bustioii, of them inthecourfe of the procefs, as there is when oxygen is put to the fame fubftance, and heated with it afterwards. Here, however, oxygen meets carbone, a Combuftible fubftance, in a red heat, without any explofion or combuftion taking place. Thus do the antiphlogiftians boaft of the difcovery of* a new oxide, when they are unable to prove that it contains a particle of oxygen, and when its obvious properties fhew that it belongs to a clafs of fubftances the •'• • *fMr Chenevix, a chemist of the first class in the new school, speak- gig of-Mr. Cruikshank, caUs him very justly " an abl« cheraist, to v.hora " we arc indebted f rr the disco-, eiy of the gaieous oxide of carbolic." See Fuiiosnf.'jkai Ttansacticne for a. u. 1802, ;>. 133. Phlogifton eflablifhed. 33 the very reverfeot oxides. If the discovery, as it is called, relates to the substance, it hi 0.15s to mj \YL that they can pretend to is havi 15 ,.£wea a better ac- count of the nature of it, and »vith wiiat fuccefs they have done this let the impartial reader judge. ------"•rnmi.n'r"1™* SECTION V. Of the Calces of Zinc. T JL HE only circumftarice that gives any plaufibility to the opinion of finery cinder being an oxide of iron is the addition that is made to the weight of the iron when it is converted into this calx. But when zinc is treated in the fame manner, fteam being ftnt over it in a re 1 heat, tho' inflammable air is procured, the zinc gains no addit;u i of weight; fo that in this cafe there is no pretence whatever for faying that the water is decompofed. The fubftance that is produced in th<-fe circumftanc- es I have fomewhere called flexvers of zi c becaufe it is a calx of zinc ; and at that time * prefu. ' that it muft have all die properties of the common flowers of C zinc* 34 The Doctrine of zinc, arid contain oxygen. But I have treated this pe" culiar calx of zinc, made without accefs of air, in :.ll the methods that I can think of, without being able to find any appearance of oxygen in it, ai()- more than in'finery cinder. When 1 heated it in common air, the air was not increafsd but dimmifhed, the ve.ry fame effea that is produced by the finery cinder. Having put an ounce of zinc into a glazed earthen tube, to which I gave a red hear, I made fteam pafs o- ver it 'ill I had procured three hundred ounce meafures of infl.unmable air. after which I found the greateft part of the zinc reduced to a dark coloured femitranfparent glafs, adhering pretty clofely to the tube. I was able, however to feparate them, and I am confident that the calx did not weigh more than the metal had done; whereas, computing from the proportion of eighty five parts of oxygen to fifteen of hydrogen (into which it is faid that water is refolvable) it ought to have gained a- bout a hundred grains. Since, then, this great propor- tion of oxygen is not found either in the calx, or in the- Water (for this I alfo examined) where will the antiphlo- giftians fay that we are to look for it ? For fince the water, they fay, is decortlpofed, in order to furnifh the inflammable air, it ought to be found fomewhere. Another experiment that I made with zinc proves that when inflammable air is procured by means of it, it muft come from the metal, and not from any water. On throwing the focus of a burning lens on a quan- tity of zinc in common air, confined by water, in a glafs veffel, the firft effea is the produaion offloxvers of zinc, which Phlogifton eftabtifJied. gg Which mike a beautiful appearance, by their difperfion within the veffel; and during this part of the procefs th.- air isdiminhhed, the pur; part of it, no doubt, en- teri:g the calx, while the phlogifticated part remains unaffeaed. After this, the application of the heat be- ing continued, there is an increafe of the quantity of air by the produaion of inflammable air ; and inflead of flowers of zinc, a black powder arifts, and adheres to the infide of the veffel, and with care may be colka« ed. Now, fince inflammable air is prrdur,ed, the anti- phlogiftians muft fay, thai part of the water over which the experiment was made, was decompofed. But tb.n 1 afk, where is the oxygen, which, according to th-m, conftitutes the far greater part of the water ? 1 cannot £,;d it any where The water is entirely free from a- cidity and the air expelled from it afterwards is even lefs pure t*?an that which it yields before the procefs. And if I examin" &£ black powder (which muft be the metal fubhmed) by heating it in confined common air, it becomes a whitifh ^fubftance, the air is diminifhcd, and rendered in a confiderabk degrc « impure ; where- as, if it had contained any oxygen, the quantity would have been increafed, and it would have been ourer than common air; as when red precipitate, or mini?™} is treated in the fame manner. It is evident thereforl!*j that it contained no oxygen, but a quantity of phldgif- ton,on the exj uKion of which, and the imbibing of pure air, it became flowers of zinc. This experiment is rather more dec^-ve than the fimilar one with iron, becaufc* the j.a.i powder to which, C % zinc *6 The Doctrine of zinc is reduced can be afft-aed by heat in common air, which finery cinder cannot. It willhardl be pretended that the oxygen ariling from the decompofition of the water is lodged in the flowers of zinc , fince they were completely formed be- fore any inflammable air was procured. Befides it will appear that little or no oxygen can be found in flower* Of zinc produced in any procefs. As I could not find auv oxygen i i the precipitates of iron diffolved in acids, I have not been a'.l.j to find any in thofe of zinc. The moft unexceptionable ih:it I could think of was that b> caulhc volatile alkali. This fubftance I heattd in a.mofphencal air, both moift and dry (left expofun to the atmofphere ihould have made fome difi\ rence in :t) but it was with the f me refult. The air in which it was heated was made more impure than it was before, tho' in one cafe the quantity was in- creafed from fix and an half to eight ounce meafures. Of this half an ounce meafure was fixed air, and the re- mainder of the ftandard 1. 8. extinguifhing a candle, fo that it was almoft wholly phlogifticated. It feemed, therefore, to have imbibed part of the pure air, and to have given out phlogifticated air.. Filings of zinc yield much inflammable air in pure water, tho' I do not find that they (an by this means be reduced to a complete calx. * But the imperfea calx to which the metal is then reduced, does no: appear to contain any oxygen. When it was heated in atmof- pherical * Since this was first.printed in the Medical 1-'<.-/y-tltci v, I find that, fey long standing, the surface :t of theaddiiion ot weig-.t whsch fhey by this means ac- quire is from Witer, w nile the oxjgen attaches itklf to other fubftances in \ reference to thecalx, if they be pre- fent. One inftance oft this ie that when they are calcined with a burning lens over lime water, the lime is preti- pitated ; whereas if the calx had imbibed all the de- phlogifticated air that difappeaed, the lime waterwould not have been affeaed in the procefs; thi6 precipitation oi the lime, coming, no doubt, from fixed air, which I have fufficientlv proved to confift of dephlogifticated air and phlogifton, or the bafe of inflammable air. I had this refult when led ined iron, copper, zinc, tin, lead, bif- muth, and regulus of antimony in thefe circumftances. But when the procefs v.v.s made over mercury, I could not always find any fixed air ; and therefore I prefume that all the oxygen was imbibed by tlu calx, tho' it may fee impoilibie in man; cafes to extraa it again in that C 3 form 3« The Doctrine of form. For when the quantity is fmall, it may be f« united to the phlogifton remaining in the calx, as to form the bafis of phlogifticated air, which I have proved to confift of dephlogifticated and inflammable air. Leadfurnifhes an example of this. No oxvgen I believe can by any means be got\from massicot, tho' it ha^ imbibed fome. But when this calx is fuperfatu- rated with it, and is become minium, it will vield the pureft dephlogifticated air by heat only, and will like- wife dephlogifticate marine acid. And fince flowers of zinc will not dephlogifticate marine acid, I prefume that this calx alfo is nearly in the fame ftate w-th mafli- cot in this refpea; and that in any ftate it contains but little ox} gen, or fo united to phlogifton as not to be ex. traaed either in the form of acid, or of dephlogifticated air. Tho' the flowers of zinc mav contain fome oxygen, J have not been able to difcover any in them by any pro- cefs that I have made ufe of for the purpofe. As this fubftance is formed in a confiderable degree of heat, I was not furprized to find that heat would not expel any thing from it; but I thought that when it was mixed With iron filings it might with them, yield fome fix.' d air, as red precipitate does But I did not find this to be the cafe. I got nothing in this procefs befides inflam- mable air. Alfo, when mixed with perfea charcoal, fuch as gives no air with heat, a great quantity of both fixed and inflammable air is produced ; which fliews that, like this fubftance, flowers of zinc contain little or nothing befides water, which will have juft the fame pffea. To Phlogifton 't/tgbjyited, 39 To make this experiment with fairnefs, the iron filings muft be heated till they give no air. 1 hey muft then be well walhed, till the water put on them be quite clear, and be again found to give no fixed air with heat. For foreign fubftances are very apt to be mixed with iron filings, and this procefs will feparate them. With iron filings thus prepared, red precipitate g:ves fixed air, buf flowers of zinc none. There is a grey talx of zinc fimilar to that of leadf which Mr. Chaptal calls a perfect oxyd. This 1 find to be only zr~c partially calcined. For on heating it in atmofpherical air it became white, the air was di- minifhed, was without fixed air, and conliderably phlo- gifticated. Theperfea flowers of zinc treated in the fame manner made no fenfible change in the quantity of the air; but, as in the former cafe, there was no fix* eel air in it, and it was considerably phlogifticated. The melting of mafficot in thefe circumftances made no change of any kind in the air, which fliews that it contains no more phlogifton than flowers of zinc. Oxygen in a calx is perhaps moft eafily deteaed by its forming fixed air when it is heated in inflammable air ; but I did not find this to be the refult of an at- tempt to revive flowers of zinc in thofe circumftances. Owing to the whitenefs of this fubftance, which difpofes it to refiea, and not to abforb, the light that is thrown upon it, I could not revive any part of this calx com- pletely. A black fpot only was made on a part of it, and abouf an ounce meafure of inflammable air was imbibed ; but 1 found no fixed air in the remainder, any more than I did when I revived finery cinder in the fame -rocefs. S<iON 40 ■•< The Doctrine of t . • :.■■ .'firi- :' .. ••/■! SECTION VI. Arguments in Favour of the Doctrine of Phlogiston from some C:ra instances in which Sulphur is formed, and nitrous Acd phlogisticated. 1. jl\.N argument may, I think, be drawn in favour of the doarine of phlogifton from my experi- r. :nt of the formation of fulphur irom the acid of vi- triol heated in inflammable air, and alio from water impregnated will- v u inlic acid an, expofed in a clofe veffel to a continued heat. Sulphtr, the antiphh giftians fay is a limp's fub- ftance, and that the vitriolic acid is m.-.i fubliance with the addition of oxygen, or dephlr,gii hen;, iail.fr than in the procefs with water impregnate c! w.th Vitn< nc acid air? For when this air is procuree; b} making the acid pafs through a red hot earthen tube, r.o iuljhur is found. But when it is heated to drynefs in inflammable air, which can fupply it with phlogifton, fulphur is form- ed, The Phlogifton eflabliflied. 41 The produaion of phosphorus from the phofphoric acid heated in inflammable air furmfhes theia.u- proof of thi^ fubftance alfo being a compound, and that phlo- gifton enters into'the compofit^on of it, as well as into fulphur. According to the phlo^iftic theory, the formation of fulphur from water impregnated with vitriolic acid air is very eafy ; both the ingredients of which it is com- pofed bei-'g prefent, viz. its bans, vitriolic acid, and. phlog'fton. They are only made to form a different mode of combination b\ the he.it in a tube hermetically fealed. For the vitriolic acid air is produced by heat- ing in vitriolic acid moft of the met ds, or any other fubftance, folid or liquid, that is faid to contain phlo- gifton. If it be faid that the fulphur may be formed in this experiment by the heat of feparating the acid from its bafe ; I anfwer that then the remaining water fhould be more acid than before ; whereas I find it to be lefs fo. This dimunition of acidity I account for from the ex- treme volatility of this phlogifticated acid. But hid the acid been that of vitriol unphlogifticated, it would have been obftinately retained by the water, feihies, it would, furely, be more e?Sy to expel all acid from a liquor pafling through a red hot open tube, than from a liquor confined in a glafs tube, hermetically fei;ied, fo that it canr.ct poff.bly efcope ; and wh.cn it is expo- fed "to no more than a moderate degree cf heat. F r had it approached to a red he.-.t, the t-:';e would have burft- But the formation of fvlrhur and phof h.-^ru"., by C J hea.ing 42 The Doctrine of heating the vitriolic and phofpfioric acids, fo as to e- vaporate them to drynefs, in inflammable air, which then difappears, and this effea not being produced with- out it, or fome other fubftance containing phlogifton, is, I think, decifive in favour of their receiving an addi- tion of fomething from the inflammable air, or phlo- gifton, When they are converted into fulphur and phof- phorus; and therefore that thefe fubftances are the com- pounds, and the acids the more fimple fubftances of the two. 2. It is faid by the antiphlogiftians that the nitrous acid never becomes coloured by imbibing any thing, but always in confequence of giving out oxygen. I think, however, that the contrary is proved by its ab- forbing nitrous air, which it does with great rapidity. But the fame effea is produced, tho' not in fo remark- able a manner, by means of inflammable air. I put a quantity of dephlogifticated nitrous acid in- to a phial with a ground glafs ftopper, with inflamma- ble air oR its furface ; and in another fimilar phial at- mofpherical air was confined with it. Both thefe phi- als I covered with water in inverted glafs jars, to pre- vent their having any communication with the atmof- phere. After long expofure in thefe circumftances, that which had the common air tin its furface never ac- quired any colour, or only a very little, from the effea of light tranfmitled through two glaffes with water be- tween them ; but that on the furface of which inflam- mable air was incumbent acquired colour very foon. I alfo found, on repeating the experiment, that a part of the Phlogifton eftabhfhed. 43 the mfb aable air had been imbibed by the acid. In order to make this experiment, a phial filled with the acid muft be introduced into ajar of inflammable air ; and, part of it being poured out, the ftopper muft be put into it in that fituation. Other precautions muft be lied which a little experience will teach* SECTION VII. Of the Calces of Mercury. T J HE phlogiftic theory, I readily acknowledge is moft preffed by the phenomena of the calces of mer- cury. But in forming any general theory we muft content ourfelves with the feweft difficulties. It will hardly be pretended by the greateft admirers of the an- tiphlogiftic theory, that it is attended with none. Thofe which attend the phlogiftic with refpeel to thefe c-alcsr, I do not think to be hrfupcrable, and farther experi- ments may throw more light upon them. As there are calces of mercury which certainly im- bibe inflammable air, this fubftance, or the bafe of it, phlogifton 4{ The DoHrhesf phiogiflon, htuflbe concluded toex'ft in thatmetala* ■* an element.- Thi* is true both wyth refpedk to red 'pre- cipitate, and teVfrrth'tnineral. ■■•'■•. . . ' As to the'calx of mercury from the acid of vitriol, RTr. Beau me "vl find;: agrees with me in the obfervation, tho' I did notkrrtJW 'tat the time, that it is-not com- plcdy reduceable by mere heat.But "later obfervation1,' Dr his-lean lays, p 11, " fliews that the turbith min- " era!, or a-y other fubftance in'o which it may be con- '« ver'.ec: b\ a r. d iieat, does not require anv addition to '- conftitute it a metal -""and P*.-r. Adet lavs, p. 43, " that th? yellow critV of rrercun h;-s been revived " without cVdiiicu b\ IV'ciTis. AJonnet, Eouqutt,L..voi- " fier, and Founro)." I o this J can-only lay. 'hat 1 have never been ab'e to reduce the whole <■{ this calx by an\ heat that 1 could apply, rrt even that of a burnii g lens of fixteen inches dhin-eUi , and this, I am confident, is^a greater heat than can be raifed by any fu nace whatever. From btinja red friable fuUl.'.nce, this In at converts it into ? ycllowifii glafs, wiih the lofs of about three tenths of in weight,- -but after this-j-r.o continuance of the fame h< Lit makes itnv farther change in it. Yet after this, when it is heated m inflammable air, the air is imbibed, and it is covered with a black powder evidently ethiops mineral, into which mercury, with all its component parts, * With Mr. Beanrne I was a little acquainted. Mr. Macque r mtito- mv.-co nT^>c"cr,:: of th" whole i x the pneumatic chemistry, he was a good operator in the c\A vrv ; ard his fres, I am persuaded, were as hot as s»riy raised by the p:; sous mentioned by Mr. Adet, or those by Dr. \ Phlogifton eftabli/hrd. 45 parti, Whatever they be,' is known to enter. This fub- ftance al.'o, and n n directly running :n rcury, was fre- quently the refu". of my experhn -nts on. this precip ..t'.e before I left Engl i A. This is certainly an e: * edair. For there was n quantity of this aif found in it, tho' 1 have {(• h found a little of it in this procefs. Nor cantbsdiftc nee in the refult be thought extraordinary, u xen it is confidereu that fixed air ceriainlv confifis of f r< ir and inflammab's air, and that it is found in olher :effes fimilar to this. In another experin *nt c nis kind I revived a quan- tity of the precipitate a thin ounce meafures of inflam- mable air, till twelve ou.nc.: meafures difappeared, and the ftandard of the r \tk er, examined as in the pre- ceding cafe, //as , » F:om this it appeared that 1.495 ounce mea. .3 o. air had been expelled from the calx, and that i • )$ ounce meafures of inflam- mable air had be .: mil bed by it. Since much o. the ca»x was fublimed in the procefs, the beft method ■far<- ? taining how much inflammable air is imbibed i en vival of a given quantity of mer- cury, is to cemp; quantity of pure air that is yield- ed by a given q-;:' ,' .y of the calx with the quantit) of inflammable air i- correfponds to it in thefe experi- ments. Now an ence of the precipitate yields about fixty ounce meafures of pure air; and fince in thefe experiments 46. 71 ounce meafures of inflamma- ble air were abfoibed when 8. 71 ounce meafures of pure air were emitted, fixty ounce meafures could not be expelled without the abfoiption of three hun» dred and twenty three ounce meafures of inflam- mable air ; and fince mercury gains, as Mr. Chaptal fays, about 8 per cent, in being converted into precipi- tate, an ounce of mercury muft contain three hundred and Phlogifton ejtablifhed. 47 and fixty two ounce meafures of inflammable air, or ra- ther the phlogifton that enters into it. An ounce of lead, I have fliewn, requires one hundred and eight ounce meafures of inflammable air, an ounce of bif- muth one hundred and eighty five, of tin three hundred and feventy feven, of copper from verditer, four hun- dred and three, and of iron eight hundred and ninety. That mercury revived either by inflammable air, or in clofe veffes, has the fame properties will not be denied ; and if fo, it muft confift of the fame principles, and in the fame proportions, or nearly fo. I am there- fore inclined to think, improbable as it may appear, that the fame principle which is effential to the conftitution of inflammable air, that is phlogifton, paffes from the fewel through the hot glafs when the calx is revived by heat in a glafs veffel. There is however, only the choice of this difficulty, and of that of an ounce of mercury containing either three hrndred and fixty two ounce meafures of inflam- mable air (that is the phlogifton in it) or none at all. It is not denied that light and heat, both of which are allowed to be substances, tho' the weight of them cannot be afcertained, pafs through glafs. They both have certain properties, and are transferable from one fubftance to another, according to their known affini- ties. And why may not this be the cafe with phlogiston '• alfo ? The electric matter paffes readily through glafs when it is very hot, tho' it will not when it 'is cold. Light certainly paffes through glafs ; and is known to give to fome fabftanccs colour, /'mell, and tafte, which 48 The Doctrine of which have ufually been afcribed to phlogifton. That it does not revive the lead in paffmg through the hot flint glafs, is no fufficient objection. For the fame fubftanc- es in different combinations, and in different ftates, have different properties. The doctrine of chemical af:;n:ties has yet many difficulties attending it, and it re- quires the niceft difcrimination of circumftances to make confiftent tables of them. However, I can only propofe facts, let others account for them in the beft: manner that they can. Mr. Scheele fuppofed that even dephlogifticated air, or the effential element of it, paff- ed through glafs. I have frequently repeated this experiment of the revival of red precipitate in inflammable air, and have never failed to find a great abforption of it, whether there was any fixed air in the remainder or not; and I ihould have repeated it much oftener, and on a larger fcale, in order to afcertain with more exa&nefs the quantity cf inflammable air, or of phlogifton* contained in a given quantity of mercury, but that it has frequent- ly happened that the veffels in which I made the expe- riments were exploded, after a fufficient quantity of pure air was expelled from the calx. This accident, however, is a proof that the air expelled from the pre- cipitate had not formed either water or fixed air. Sometimes, however, I have made the greateft part of the inflammable air to difappear without any explo- fion. The accuracy of this experiment being queftioned by Dr. Woodhoufe, I repeated it with all the attention I could give to it, and had the following refult. I heat- ed Phlogifton tjlablifhed. . aq ed a quantity of red precipitate in twenty eight and an half ounce meafures of inflammable air, till it was re- duced to twenty four and an half, and found that, where- as before the procefs it was not in the leaft affected by nitrous air ; the ftandard of it was afterwards 1. 8 ; fo that it contained a confiderable mixture of dephlogifti- cated air. I repeated the experiment feve*al times, and always found pure air mixed with the inflammable, when I had revived any part of the calx. Continuing one of thefe proceffes, till, after the di- munition, the quantity of air began to increafe, there was an explofion ; but it only raifed the receiver in which the air was confined about an inch, and recover- ing its pofition, it broke the earthen difh in which it was placed. After this 1 made ufe of a tin difh, and repeating the experiment, there was an explofion fo loud, that a perfon at a confiderable diftance was alarmed, and came running to fee what had happened. The receiver, which was a very heavy one, was blown much higher than my head ; but falling on the grafs, it was not bro- ken. After this, I thought it unneceffary to make any more experiments of the kind. Having formerly made many experiments on the revival of red precipitate in inflammable air, when I was a convert to the doctrine of the compofition of water, I fh ill fubjoin what I then obferved with refpect to the fubject from the 6th volume of ir.y Observations on air, p. \Z3. *'The greateft difficulty that occurred with re fpeci " to tie theory of the conftituiion of water, arofe from. D "-my 50 The Doctrine of " my never having been able to procure any tuater when '< I revived mercury from red precipitate in inflamma- " ble air, or at leaft more than may be fuppofed to have " been contained in the inflammable air. In order to u make the experiment with the scales ofiront and that " with the precipitate, as much a alike as poffible, and " that I might compare them to the greateft advantage, " I made them immediately one after the oiher, and " with e very circumftance as nearly as I could the fame. '« 1 he inflammable air was the fame in both experi- " ments, and the fcales of iron, and the precipitate, " were made as drv as poffible. They were heated in " veffels of the fame fize and form, and equally confin- " ed by dry mercury. And yet when I heated the " former, water was formed as copioufly as I have def- " cribed it before, viz. actually running down the infide " of the veffel in drops, tho' only four ounce meafures " of inflammable air were abforbed. Buc tho' I heat- " ed the precipitate till eight ounce meafures of the air •' was abforbed, and only three fourths of an ounce mea- " fure remained, there was hardly any fenfible quanti- " ty of water produced, certainly not one tenth of what " appeared in the experiment with the fcales of iron. t( 1 here was this difference, however, in the two rc- " fults. In what remained from the experiment with " the precipitate I at this time perceived a flight ap- " pearance of fixed air, whereas there w;s none in ''what remained in the fcales of iron. The refiduum " alio from the precipitate had in it a fmall portion of (i dephlogifticated air. For being mixed with an equ.d " measure of nitrous air tlu ftar.dard of it was 1. 8-. In «' til 13 Phlogifton cftablifhedt t% «' this experiment there can be rto doubt but that the «« dephlogifticated air diflodged from the precipitate " mixed with the inflammable air in the veff 1, and as " no water was produced, they muft have formed lotne " morefolid fubftance, which in the final quantity I was ** obliged to ufe could not be found." At this time, however, I think it more proh-d.}® that nothing solid was produced, but only that the phlo- gifton of the inflammable air was imbibed by the calx, while the pure air emitted from it was in part found mixed with the inflammable air in the veffel, and in part united with it and formed fixed air. In nine ounce meafures of inflammable air ffom malleable iron and water I revived part of the precipi- tate fent me by Mr. Berthollet, (which I had found to contain no fixed air) till not more than one fourth of the air remained unibforbed ; and examining it, 1 found one twentieth part of it fixed air. But mixing nitrous air with it, it appeared that the air diflodged from the precipitate had not wholly united with the inflammable air. For being mixed with an equal quantity of nitrous air it occupied the fpace of 1. 71. After the procefs I miffed eighteen grains of the precipitate; But there are feveral caufes of lots in this cafe, befides that from the air expelled from it. In 5. 5 ounce meafures of the fame inflammable air I again revived fome of the fame precipitate -W it was reduced to O. 77 of an ounce meafure. Oi this one fixth part was fixed air, and the reft of the ftandard of 1.6. It exploded at once when a flame of a candle was prefented to it. D 2 In $* TH Purine cf In making thefe experiments over mercery, we fi£« ceffarily m'e bat fmall quantities of air, and therefore the rtfults may not in fome refpects be fo much depend- ed upon. But 1 think it fvificientlv appears from them that no water was formed in the procefs, and this the new theory abfoiutely requires. On the whole, 1 think it can hardly be denied that confidering the great quantity of inflammable air thajfc difappears in thefe experiments, the greateft part of it, at leaft, muft enttr into the calx. And fince all running mercury muft confift of the fame elements, the. fame principle that (with the addition of water) forms in- flammable air, and which we cuU phlogifton, muft pafs through the red hot glafs when the cabs of mercury is; revived without addition, by means of heat only; Some experiments that I have made on filver, gold, And platina, favour this hypothefis. All thefe metals yield a confiderable quantity of nitrous air, when they are diffolved, the firft in nitrous acid, and the laft two in aqua regia. And When the folutions were evapora- ted, and the refiduums heated in inflammable air, a great quantity of it clifappeared, and the metals were revived. And yet by means of the fame acids thefe dry refiduums will yield a great quantity of nitrous air. They muft, therefore, have acq ;red by means of heat only, and this trani'miited through a veffel not red hot, the lame principle that was communicated to them by imbibing in!Ian triable air That nitrous air comrins the fame principle with inflammable air, or phlogifton, appeurs from the fol- lowing PhlogiiitifteftablijJicd. 53 iBWin^SXpefimen*, in Which the former was produced by means of the latter, if the nitrated calx of any metal te heated in it. If copper be ditfolved in nitrdiife acid, and the wa- ter'be eipelled to a certain point', there remains & green Intbstahfre, which is not at all dtfiqtre ft ent; but'when txlpofed'to heat gives out aredvarpour. Some of this fubftance I heated in twenty one ounce measures 'fin- flammable air till the veffel was fihtdwith red vapour, irvhen it was reduced to fix ounce raeafurra," and I found thai! When it 'wa3 mixed wnh common air, the ftand- ard was 1. 35 ; To that it was a'moft wholly nitrous air» Thefe was in it a fmall quantit\ of fixed air, bu* there was nothing inflammable in it. It extinguifhed 2 candle. Tformerly endeavoured to afceitain the proportion of phl*gifton in nitrous aud inflammable air, and found it to be nearly the fame in both. That this is not far from the truth, may, I think, appear from comparing the refult of two c f my former experiments, which I never before thought of doing with this view. When I firft difcovered nitrous air, I endeavoured to find what quantity of it would be yielded by the different metals, and found that twenty grains of iron yielded fixteen ounce meafures. When, with other views, I endeavoured to afcertain the quantity of inflammable air that was yielded by malleable iron, I found that one hundred and twenty grains of it yielded ninety fix ounce meafures ; and this is exactly the quantity of nitrous- air that the fame weight of iron would give. For 120 i-s teC6 as JO is to 16. D 3 Twenty 54 The Doctrine of Twenty grains of platina gave nine ounce meafure^ of pure nitrous air, and twenty two grains o£ gold gave eight ounce meafures. They therefore contain nearly the fame proportion of phlogifton (for 2Q is to 9 as 22 i? to 9. 9) and little more than half as much as iron. For it will be in the proportion of one hundred and feventy ounce meafoifb to the ounce. It is, however, more fi; r. is contained in lead, but lefs than inbifmuth, and r..~- his than in mercury. l.at fometh'ng can pafs through glafs is evident from man., obfervations ri fpecting both light and heat, one of the moft remarkable of which is perhaps that of mirTum, or rtd precipitate (which when cold are of the colour oi arterial bleed) heated in a glafs tube, ac- quiring tl e dark colour of venous blood, tho' they lofe it again when thej heroine cold M hat to infer from $ii* curious fact I do not diflinctly fee. SECTION Phlogifton. eftahlifted. 55 SECTION VIII. Experiments on heating Manganese in inflammable Air. UOME experiments that I made on heating manganefe in inflammable air authorize the fame gen- eral conclufion with thofe on heating red precipitate in that kind of air, and therefore deferve to be.recited. Manganefe and red precipitate of mercury are fub- ftances of a fimilar nature, as they are both calces of >metals, and both contain dephlogifticated air, and, like all other calces of metals, they imbibe the inflammable air in which they are heated. But whereas the dephlo- gifticated air expelled from the precipitate, frequently at leaft, remains mixed with the inflammable air (which is fometimes the caufe of dangerous explofioas) this has never happened to me in confequence of heating man- ganefe in the fame circumftances, fo that it may be ope- rated upon without any apprehenfion. Tho' in thefe experiments the inflammable air difappears, and dephlogifticated air is expelled from both the fubftances, no water is formed by means of either of them, as the new theory abfolutely requires, and which is pretended to be the cafe when finery chi- ller is heated inthe fame circumftances. But fince the D 4 fitmc 5$ The bttftitii. of " fame quantity of inflammated air difappears in alf thefe cafes alike, the fame quantity of water, if inflamablc air be readilv a conftituent part of it, ought to be pro- duced. It is evident, therefore, that the water produc- ed by means of finery cinder was actually contained in that fubftance, and only expelled by the heat, to make room for the phlogifton which then enters into it, by the abforption of the inflammable ak ; while, the preci- pitate and manganefe, containing no water, imbibe the inflammable air without any appearance of waTer, ex- empt the. iitfle that is the bafis of the inflammable air, or may be concealed in fuch powdery fubftances as man- ganefe and the precipitate arc. The principal difference,, however, in the refult of thefe two fimilar proceffes is that in the experiment with the manganefe a quantity of phlogistiCUted air appears to be generated, which is not the cafe with the precipi- tate. The particulars of the experiments were as fol- lows. Fifteen ounce meafures of inflammable air were re- duced to fcven by heating in it twenty four grains of manganefe. In the refiduum, which wat not affected by ntrous air, there was no IWe;1 -*ir ; but when a cer- tain po-iien of it was fired together with ;; certain quan- tity of dephlogifticated air, the dimtfrhion was only to 0. 95 ; whereas when the fame quantity of the fame o- riginal inflammable air was exploded in the fame cir- cumftances, the dimunitlcn was to 0. 5a. In another fimilar experiment,, in which the inflammable air was confined by mercury, ?.r.d in v.hieh feven ounce mea- fcres r, ere reduced to e c and a quarter, the dimunitiort wit-h Phlogifton eftabli/hed. 57 with the refiduum was to 0. 93, when that with the ori- ginal inflammable air was to 0. 33. The manganefe I ufed in thefe experiments yielded dephlogifticated air without any mixture of fixed air. I repeated this experiment with manganefe out of which air had been expelled with a ftrong heat, and the refult was the fame as with thefrefh manganefe, except that much more heat was neceflVry to make it imbibe the air ; whereas* the manganefe from which the dephlo- gifticated air has been expelled imbibes inflammable air very rapidly, and with a very moderate degree of heat. Twenty grains of it imbibed eight onnee! meafures of inflammable air, and then weighed nineteen grains. In both the kinds7 of manganefe .'the central part on which the focus of the lens fell was of a beautiful green co- lour, but the next day this had disappeared, and the whole of the fubftance that had been heated was brown. As no doubt dephlogifticated air is expelled from the manganefe in thefe experiments, and neither fixed air nor water is produced, the dephlogifticated air muft: enter into the fixed air that is found in the refiduum. In order to make a more exact cenrn ifon between the experiments in which marganefe and finery cinder were made to imbibe inflammable air, I repeated them both in fimilar Veffels, with equal quantities of inflam- mable air confined, by mercury; and I obferved th;;< iho5 fome Water appeared during the procefs with the manganefe, it wholly difappeared the next morning; whereas the infield of the veffel in which the finerv chi- de r had been.revived was wholly covered with innume-> rahle di ops of water, contiguous to one another. SECTION 59 The Doctrine of SECTION IX. Of the Decomposition of Water. T J,, HE antiphlogiftic theory has received its greateft fupport from the fuppofed difcovery that water ss refolvable into two principles, one that of oxygen,- the bafe of dephlogifticated air, and the other (becaufe it has no other origin than water) hydrogen, or that which with the addition of calorique, or the element of heat, conftitutcs inflammable air. " One of the parts of " the modern doctrine the moft folidly eftablifhed, fay " Mr. Berthollet, and the other authors of the Report " on this fubject (Examination of Kirwan, p. 1 7) is " the formation, the decompofition, and recompofition, 11 of w$iter. And how can we doubt of it, when we fee " that, in burning together fifteen grains of inflammable " air, and eighty-five of vital air, we obtain exactly an " hundred grains of water, in which, by decompofition, » we find again the fame principles, and in the fame proportions. If we doubt of a truth eftablifhed by "experiments fo fimple, and palpable, there would be (l.V'ihhg eeitain in natural philofophy. We might " even Phlogifton eftablifhed. g§ « even queftion whether vitriolated tartar be compof* *• ed of vitriolic acid and'fixed alkalij or fal ammoniac ** of the marine acid and volatile alkali, &o, &c. For the* « proofs ihat we have of the compofition of thefe falts (( are of ih f me kind, and not more rigorous than " thofe which eftablrfh the compofition of water. Noth- " ing perhaps more clearly proves the weaknefs of the *' old theory, than the forced explanation's, that have been attempted to he riven of thefe experiments." Notwithftanding the confidence thus ftronglyex- preffed by thefe a.de and experienced chemifts, I muft take the liberty to fay, that the experiments to which they allude appear to me to be very liable to exception, and that the doctrine of phlogifton eafily accpunts for all that they obferved. Their proof that water is decompofed, and refolved into two kinds of air, is that when fteam is made to pafs over red-hot iron inflammable air is produced, and the iron acquires an addition of weight, becoming what is ealled finery cinder, but what they call an oxide of iron ; fuppofing that there is lodged in it the oxygen which was one of the conftituent parts of the water expended in the procefs, while the other part, or the hydrogen, with the addition of heat, affumed the form of ir.flam, mable air. But in order to prove that this addition of weio-htto the iron is really oxygen, they ought to be able to exhi- bit it in the form of dephlogifticated air,or of fome other fubftance into which oxigen is allowed to enter, and this thev have not done. Iron that has really imbibed air, cu the common rust of iron, has a verv different app-avance m The Doctrine'of appearance from the finery cinder, being red, and nof black ; and when treated in fimi'ar proceffcs, exhibit^ very different refults. Mr. Fourcroy fays, 'Ibid p. 251) that this finery cinder is u iron partially oxygenated." Hut if that were the cafe, it would go on to attract miore oxygen, and in time become a proper ruft of iron completely oxygenated ; w h< rt as this is fo far fr< m be* ing the cafe, that as 1 have obfeived fir try cinder ntver will acquire ruft ; which fhews that the iron in ths ftate is faturated with fome very different principle, which even excludes that which would have converted it into ruft. However, neither this, nor any other calx of iron, can be revived unlefs it be heated in inflammable air, which it eagerly imbibes, or in contact with fome other fubftance which has been fuppofed to contain phlogif. ton. The probability therefore is, that the phlogifton then enters this calx of iron, replacing that which had been expelled to form the inflammable air. Nor can any inflammable air be procured in this procefs with fteam, but by means of fome fubftance which has been fuppofed to contain phlogifton. Where then, is the certain proof that water is decompofed in this pro- cefs ? Since, according to the antiphlogiftic theory, water itfelf contains all the elements of both dephlogifticated and inflammable air, and wants only calorique, which they can give at pleafure, I fee no reafon why heat a- lone, without the aid of any metal, might not convert it into air. When the particles are fo far feparated as they are iri a ftate of fleam, I fee nooccafion for the fu- perier Phlogifton eftablifhed* &\ .perior attraction of any other fubftance for either of them. In ileam each of the elements is already in tho form of air, and with its due proportion of calorique, and then why Ihould they not continue in that form,on- ly mixed together, ready for explofion ? It is faid that the oxrgen imrnbed by this iron, be-y ing expelled by heat in contact with inflammable air, unites whh hat air, and with it conftitutes the water which is t und after the procefs. But for any thing that appears, this water m ty be that which the iron had imbibed, and whieh can only be expelled from it by the- entrance of that phlogifton which it had loft. Befides it has been fhewnthat the water produced in this man- ner is much more than in the required proportion of the inflammable air that difappears. Another pretended proof that water is compofed of dephlogifticated and inflammable air, is that when the latter is burned flowly in the former, they both difap- pear, and a quantity of water is produced equal to their weight. 1 do not, however, find, that it was in more than a fingle experiment tkat the water fo produced is faid to have been entirely free from acidity, tho' this experiment was on a large fcale, not lefs than twelve ounces of water being procured. But the apparatus employed does not appear to me admit of fo much accu- racy as the conclufion requires ; and there is too much of correction, allowance, and computation in deducing the refult. A fo, it is, after all, acknowledged that, after de- compofing this qu ntpy of the two kinds of air, and making an the auowunee tiiey ceuid for phlogifticated air 6& The Doctrine of air, or nzote, in the dephlogifticated air, the experi- menters found fifty one cubic inches of this kind of ail1 more than they could well account for. 1 his quantity, therefore, and perhaps fomething more (fince the ope- rators were interefted to make it as fmall as poffible) were formed in the procefs. And when this kind of air, as well as inflammable is decompofed together with dephlogifticated air, nitrous acid is produced. The probability therefore is, thnt the acidifying principle, or the oxygen, in the dephlogifticated air which they de* cOmpofed, was contained in that phlogifticated air, and that, had the procefs been conducted m any other man- ner, it Would have affumed the form of nitrous acid. They acknowledge that, except wliee- the inf ammaVe air was burned in the sloxvest manner, the water they produced had more or lefs of acidity. The reafon, no doubt, was that, whenever the flame they made ufe of was too ftrong, more of the dephlo- gifticated air in proportion to the inflammable was con- fumed than when the flame was weak ; fo that the re- fults of their experiments exactly coincide with thofe of mine. Citizens Eerthollet and Fourcroy fay, with Mr. A- det, that" the fmall quantity of acid which is commonly " found in this procefs comes from the azote, which is u mixed with the gas." (a::,ui.ee, tie Chymie, vol. 26, p* 306.) But if this was the cafe, they could cever get water free from acidity,becaufe they can never whol- ly exclude azote. Befides, how can they think it fo eafy to procure nitrous acid from azote in this procefs, ,:, whe* Phlogifton eftabliflied. 6j ' when Mr. Cavendifh found it fo difficult to procure a barely fenfible quantity by numberlefs eledrie explo- fion s ? The experiments which 1 made on the decompofition of thefe two kinds of air in close vessels, appear to m& to be much lefs liable to exception, and the conclufion drawn from ihem is the reverie of that of the French philofophers. When dephlogifticated and inflammable air, in the proportion of a little more than one mealure of the for- mer or two of the latter (both fo pure as to contain no fenfible quantity of phlogifticated air) are inclofed in a glafs or copper vtffel, and decompofed by taking an e- le<5tric fpark it it, a highly phlogifticated nitrous acid is inftantly produced ; and the purer the airs are, the Ttronger is the acid found to be. If phlogifticated air be purpofely introduced into this mixture of dephlogis- ticated and inflammable air, ic is not affected by the procefs, though, when there is a confiderable deficiency of inflammable air, the dephlogifticated air, for want of it, will unite with the phlogifticated air, and, as in Mr. Cavendifh's experiment, form the fame acid. But fince both the kinds of air, viz. the inflammable i.nd the phlogifticated, contribute to form the fame acid, tkey muft contain the fame principle, viz. phlo^ifto:. If there be a redundancy of inflammable air in this. procefs, no acid will be produced, as in the great expe- riment, of the French chem; lis, but in the place of it there will be a quantity of phlogifticated air together with water.* M. MV;. - I fjavi^afrc.-nr.n, txl.-.U,thr.: v.!-ca W- lnmuV. .lour,c? ,r.Ga:uvccd «4 The Doctrine of> Meffrs. Berthollet and Fourcroy fay, vith.Mr. A* det, that :he water procured in this manner cannot be held in folution in the gaffes, but muft neceffarily be a new production (Annates deChymie, vol. 26, p. 306) But I do not fay that this wa^'er was held in folution in the gaffes, but was a conftituent part of them ; anu for any thing thivt is certainly known is aft that can be afccr- tained by weight. I wifh, however, to have more repe- titions of this experiment, in order to afcertain this cu- rious circumftance. I was never able to get the whole- weight of the airs in water. In my experiments, when no acid is produced a confiderable quantity of phlogifti- cated air is always formed. When the decompofition of phlogifticated and in- ilammadle air is made in a glafs veffel, a peculiar dense vapour is formed, which the eye can eafily dillinguilh not to be mere vapour of water, and if the juice of turnfole be put into the veffel, it immediately becomes of a deep red, which fliews that it was an acid vapour. Since the acid that I procured in this procefs was in confiderable quantity, and no phlogifticated air was pre- fent (for in the laXt of the experiments I did not eyen make ufe of an air pump, but firft filled the veffel with water, and then difplaced it by the mixture of the airs) I do not fee how it is poffible to account for the forma- tion of this acid but from the union oi the two kinds of air ; and it can hardly be fuppofed that, in the very fame procefs, the decompofition of the fame fubftances fhould inflir.'.rr able air were fired together v.ith fifty one measures of de- phlogisticated air acid was formed, -hut that only %:ater was produced when the same quantity of inflarer.:::b!c air -was iired with forty zc eir !»cr.rur€3 cf thj same dephlogisticated .•..;-. Phtogifton efiabltfhed. $g ftouHd compofe others fo very different frohi each other as watered spirit of nitre. I. think I have fufficiently accounted for the refult of the experiments made by the French chemifts on the common hypothefis, which fuppofes inflammable air to cot tain phlogifton; but I do not yet fee how it is poffible for them to explain mine bh theirsj according to which there is no fuch principle hi nature. Upon the whole, it does not appear to me that the evidence either for the Compofition, or the de- compofition at water, is at all fatisfactory ; and certain- ly the arguments in funport oi an hypothefis fo extraor- dinary, and fo novel, ought to be of the moll conclufive kind. Dr. Maclean boafta greatly of the fuperior accuracy if the French chemifts. " In what refpects," fays he, p. 45, " his experiments (meaning mine) were lefs lia- '« ble to exception than thofe of the French chemifts, is " what I do not comprehend. Theirs Were performed '* on a very extenfive fcale, great care was taken to af- " certain the degree of purity of the gaffes before com* " bullion, and the apparatus was fo conftructed, that the • '~> ..i ■.::...-Mf:'i:. rrra.7- v. 1 ■ cl A CCORD1NG to the new theory, water confifts of two principles, ox\g n and hydrogen ; and they are feparated by iron, or charcoal, in a red heat, uniting with one of them, andfuffering the other to ef- cape ; and therefore if, in any cafe, a quantity of wa- ttr be wholly expended in forming air, and only one of the kinds be found, it will be evident that this water does not confift of two elements. Now according to one of my experiments water would appear to confift of only one of the kinds of air, and according to another of the other. I have lhewn that by a flow fupply of water in fend- ing fteam over red hot charcoal, the whole of the pro- duce is inflammable air, without any mixture of fixed air, or the production oi any thing, aerial, fluid,or folid, into -which cx\ gen tan be It ppofed to enter. From this experimtnt, therefore, conducted in this manner, it Ph)ogiffan\ eftablifhed, 71 it niight; be concluded that water confifts of hydrogen only, without any oxygen. wicz f This obfervation of mine is confirmed by.Mr.-Watt,: whofe accuracy no perfon will call.in queftion,' lie fays ■ i hefe experiment* favou* my hyi»athefis tbsttt water istht bafts of all kinds oi air, artd^hj^iortf.th^i wifch* cvut itnakind oi a>r caa>be produced''s Jr%;&fl>Q; cafes, as in tihat of the light inftamrnalbk air, it may be,*dl that can be afcertained by weight. . • • -jrh „...I .&-, Li.Tq- my\ experiments VUh fob* tjerra pqnd«r<$faj which? in nay opinion demonllrabiypirflvf^ that, watefr is^a conftituent part oi fixed air, and therfcfeffl probabjb/, o$ other ki&dsj of air alfo, Mr. Bertholletjlfthjecla (Report, p^.aa) thai I did not examine tfe$ ;lcl$o$ weight in this fubftance, But after the proceifif&t^adher* ec* fo elofelv to the earthen tube an which the expert* inent wust»sde., that the lofs of .weight' could not> bfe afcertain-ed with accuracy, This,however, wasnGtat all neceffary. J found very exactly how much fixed air a givenjquaaa,tity of this fubftance would yield by mcoms of water, whieh appeared, to be the 'f«Mtye that iij yielded by folution in ivi>r -e acid, and that ityielded nq air at all by mere heat w^hout water- It was quite fuf- ficient, therefore, to find how much water was expend- ed in procuring any quantity of fixed air from this fud> ftance. Andas there was.no Qther fource of lofs of wa- ter befides the fixed air, it (seald not but be concluded PhlogiftQ^efikbtiffkd. 7^ tkat it entered into its compofition, as a neceffary part of it, and in the proportion which I afcertained. The truly ingenious and equally candid Mr. Rupp, hints that the water might be imbibed by the terra pon- derofa ; but 1 fee no reafon to think that it did. It is not at all probabJe. thatthere |s any affinity between this fubftance and water; and If w?ter exift m it as an ex- traneous fubftance, the heat that I applied would have expelled it« , .,.,:. ,-jt-v. tt, - ., • u?. Mr. Rupp produces ,\feveral. experiments, made feemingly wit|i.great accuracy, to piove that fixed air contains no water. But experiments which require the folution of fubftances in acids, and evaporation, to- gethe'r- With the computation or thai proportion of earth, acid, a*nd water, contained in falts, are much more com- plex than mine j and therefore, will not, 1 tHink, au- thorize'fo pofitive a conclufion/ I have not repeated hi's experiments, and leave others more es$e*t than 1 amtn'fuch proceffes to judge between us."r :!3:xrr ■ * ■ » < - *- ■ £v.;l - ■ zxr.-iiv ,..; ■/, !f ., i sji^rxih: > rh'hv;; ;:_••-^ -nififlaj'i. . ^'v^ftf-uir'-.L... .ar/r, ,„n 0.:'./.,,.': r •' oi:; f. ':.;;;■!;:,] <-.'-, or ,?r -v .~i- ofmri-ri .i"3c: no x-->< SECTION .1 l»;..- 7i c .5- The Doctrine of V ( -:" . j hj : i ;dj-;-' • •;.:->» ^ ....:j ... . ,; ' r: : : -•■-■' - i:-J\r.9i e ' . ; jfl>*;/<* brrt- . > ur - .„, .' . - , „ Vu T is alleged in favour of the.decpmpqfitipn of water, that both dephlogifticated and inflamaaable" air have been procured by^ taking efectrie explofipns in water.: -.Experiments wilh this, refult, were made by Meflks.yan.Troqftwick and Deiman, and have been re- peated with the greateft attention by Dr. Pearfon. See the Philosophical Transactions for i797, p. 142. The accuracy of thefe experiments I am by no means difpofed to queftion. Both dephlogifticated and inflam- mable air, were, no doubt, produced, tho' with infinite labour, by this means ; and I confider the experiment as exceedingly curious and important in feveral ref- lects. But it is a very complex one. Several agents are concerned, and what, and how much, to afcribe to each of them is not eafy to fay. I have not yet found any termination to the production jof air from water only, and the laft product, which is equable, is wholly phlogifticated air, of the nature of which we know but little. Phlogifton eftablifhed. 75 little. Some of my experiments feem to prove that it is compofed of dephlogifticated and inflammable air ; and iight, which is peculiarly mtenfe in the electric fpark, is in my experiments on plants, and probably in other. proceffes, a neceffary ^gent in the production of de- phlogifticated air, when there is water for its?bafis. And the metals that are employed, viz. gold and platj- na, may contribute to this flow production of inflamma- ble air. But the accenfion of thefe airs being-fome- timesfpont:yneous, without the electric fpark being:tak-- en in.them, {hews ,th*t part at leaft of the air produced is phosphoric ; and, it ri well known that-the electric fpark is always accompanied with the fmell df phofpho- rus. uil,; ;;....' •i\ X hope thefe experiments will be repeated with a flill greater variety of circumftances, tho.' 1 do not fee how they can be made fo that wateri only fhall be em- ployed, except perhaps in a glafs fyphon, fo that the electric fpark fhall be made to pafs from the" water inJ one of the legs to the water in the other, and to this there are many objections. . ci.i. ... To thefe Observations I fhall fubjoin what I oblecv- ed with refpect to this experiment when I made a new arrangement of my Observations on Air, in three vo- lumes, vol, 3, p, 543. . .. "■ It muft be acknowledged that fubftances pcffeffed *' of very different properties may be compofed of the «> Came elements, in different proportions, and different' "modes of combination. It cannot, therefore, be faid " to be absolutely impoffible but that water may be com. " pofed ©f dephlogifticated and inflammable a'r, or of " anv 7 6 The Doctrine of ** any other elements. But then the fuppo&tion fhouid' " not be admitted without proof; and if a former the* »< ory will fufficiently account fov atl the facts, there is » no occafion to have recourfe to a new one, attendedi <« with no peculiar advantage." ** Alfo that phlogifton is an element, jni the compofL* "tionof water is, as 1 have more tham once ©hferved, " not at all improbable , fince water conducts ele&riciry ** like metals and charcoal, into'which the fame princi- " pie enters ; and beeaufe, when frefla diftilled, k at- ti tracts dephlogifticated air from the atmofphere^ which « is the property of other fubftances containing phlo- "gifton* By this means water may, in factj eOntain- " both the principles of which, according to the new V. theory, it wholly confifts, and in what proportion it " contains them, we cannot tell. For tho' heat may ex- *.« pel them in part, in the form of air, the force of this " action may be limited, fo that water boiled ever fo " long may retain much air, which only faeh a degree ? of heat as is communicated by electricity can difce* "ver. But this proves nothing again* the 'doctrine cf "• phlogifton ; fince it only proves that this principle is H contained in water, more or lefs intimately combined) «* as well as in many other fubftances,?' Dr. G. Fordyce found, by an experiment which has the appearance of great accuracy (See Philosophical Transactions for 1792, p. 374) that the addition of weight to zinc, when it is converted into a calx, comes from the water. But he advances nothing to prove that the water was decompofed in the procefs ; and wa- ter is all that 1 can find in flowers of zinc. Phhgiftott eftablifhed. 77 It is pretended that water is decompofed by the growth of plants acted upon by light. But if this was the cafe, why will not a plant continue to grow in the fame water till the whole of it be decompofed ? Where- as I always found that only a certain quantity of dephlo- gifticated air could by this means be procured in the fame water, and very little in proportion to its bulk. After this the production of a'.r ceafed, and the p'ant died, To me it appeared, that the food of ihe plant was th« phlogifton contained in the water. For when by tho growth of the plant the air contained in the water was perfectly pure, the procefs always ceafed. But the fame plant, removed to water that contained impure air, would grow again, and give pure air as before. See my Experiments on Air, Vol. 5, p. 25. Alfo, having put various vegetable and animal fub- ftances into water, which by putrefying became offen- five in the dark (yielding inflammable air mixed with fixed air) and when the veffel containing them was placed in the light, and green vegetable matter was fuf- fered to grow.in it, the pureft dephlogifticated air was produced; the phlogifton, as I obferved p. 42, which, in other circumftances, would have been converted in- to inflammable air, now going to the nourifhment of the plant, and by the influence of light yielding fuch pure air. On this fubjeclt I then made the following re- marks, p. (32. "It is impoffible not to obferve from th^fe experi- ** ments the admirable provifion there is in nature to •' prevent, or to leffen, the fatal effeas of putrefaaion, " efpeci- 18 The Doctrine of " efpecially in countries where the rays of the fun ai'tf " moft direa, and the heat the moft intenfe. For where- " as animal and vegetable fubftances, by fimply putrefy- M ing would neceffarily taint great1 mafles of air, and " render it wholly unfit for refpiration, the fame fab- " fiances putrefying in water, fupply a moft abundant " pabulum for this wonderful vegetable fubftance, the " feeds of which appear to be in all places, difperfed " invifibly hro' the atmofphere, and capable, at all fea- *c fons of the year, of taking root, and immediately u propagating themfelves to the greateft' exent. By •e this means, inftead of the air being corrupted," a vafl *<■ addition of the pureft air is continually thrown into « it." *« By this mean1? alfo ftagnated waters-are rendered " much lefs offenfive and unwholefome than they " would otherwife be, '1 hat froth which we fee on " the furface of fuch waters, and which is apt to create '" difguft, generally confifts of the pureft dephlogifticat- «< ed air, fupplied by aquatic plan's which always grow « m the greateft abundance, and flourifh moft, in water " that abounds with putrid matter. When the fun >< ihines thefe plants may alfo be feen to emit great " quantities of pure air." " Even where animal and vegetable fubftances pu« " trefv in air, as they have fome moifture in them, va- " rious other plants, in the form of mold, &c. find a pro- " per nutriment in them ; and by converting a confider- " able part of the phlogiftic effl ivium into theirown " nourifhment, arreft it in its progrefs to corrupt the fur- " rounding atnvjfphere. So wonderfully is every part "of Phlogifton eftablifhed. n " of the fyftem of nature formed, that good never fails *' to arife out of all the evils, to which, in confequenc© " of general laws, moft< beneficial to the whole, it is " neceffarily fubjea. It is hardly poffible for-a perfon " of a fpeculative turn not to perceive, and admiie, this " moft wonderful and excellent provifion" ' 1. Since charcoal is refolvable b\ means of water into fixed and inflammable air, and fixed air confifts of dephlogifticated air and phlogifton, thefe principles have been united in the ingenious experiments of Mr. Tenant, diverfifiedby Dr. Pearfon, fo as to form char- coal. It was accomplifhed by heating fubftances con- taining fixed air, as marble Sec. together with phofpho- rus, which contains phlogifton. This experiment has been alleged in favour of the decompofition of water ; but I only fee in it the compofiti on of a fubftance from the elements of which it was known to confift. 3. The produaion of inflammable air from liver of fulphur with water, Mr. Gingembre fays, arifes from a decompofition of this water ; becaufe without the water no inflammable air is procured. But water, I find, is neceffary to the conftitution of all kinds of air, and of inflammable air moft; evidently. 4. Mrs. Fulhame imagines that fhe has proved the decompofition of water from a number of exceedingly curious experiments on the revival of metals by means of inflammable air, phofphorus, fulphur, charcoal, and various other fubftances of a fimilar nature, becaufe the effea is never produced without the prefence ofmoif- ture. Her experiments are fuch as I fhould} not- have expeaed a priori; and when fhe wasfo obliging as to fhew #<5 The Doctrine of (hew me the refult of fome of them iri London, I wriS greatly ftruck with them ; but I do not think that tikdjr prove the decomposition of water. She does not pretend to exhibit feparately either of the parts of which the water is faid to be compofed $ fince fhe does not produce either inflammable or deph'o- giftioated air from this water ;, and fhe fuppdfes the very ut.ne quantity of water to be reCompofed that is decompofed in the proceft? Nor does (he pretehd to be a'cle to revive any metals Without fome fubftancft into which phlogifton has always been fuppofed td enter. All, therefore, that can be fairly inferred from her ingenious experiments is, that water affifts the feparat- ti&n of oxygen from the calces of metals, and the en« trance of phlogifton into them ; which it may do With* out any decompofition. Alkohoi, flie obfer\es, will not anfwer the fame purpofe. But to this it is fuffici- entto fay that alkohoi is not water, and therefore has not the fame properties* The picFence of water is ne- ceffary to the ruftingof iron, and-alfo to the acquisition of fixed air by lime j but the manner in which it contrb butes to thefe and other proceffes has not yiX been afc certained. Had fhe made her experiments with inflammable air in clofe veflels,fhe would, 1 doubt not, have found a diminution of the quantity of it, which could not be accounted for but on the fuppofition of its having enter- ed into the calx, and thereby contributed to the revival ©t the metals. S. She Phlogifton eftabti/hed. 81 8. She fays p. 163-, that " the formation of nitroui * acid in Mr, CavendiftYs noted experiment, canno' b« u explained on any other principle than the decompofi. '• tion of water." But Mr. t avendifh himfelf draws no fuch inference from it. All that I fee in it is that phlogifticated air contains the fame principle widi in- flammable air, viz phlogifton j and therefore that when they are decompofed together with dephlogifticated air, they form the fame thing, viz- nitrous acid. The water that is produced, and which adheres to the acid, I fup- jKife to be* that which is effentialto the conftitution of all kinds of air, and to be the greateft part of their weight. 6. Rain, fhe fuppofes, p. 167, to be water formed at the time from its proper elements in the upper regi- ons of the atmofphere. From the refpiration of fifties, atnd from every cafe of combuftion, fhe draws the fame cronclufion. But in every cafe (he fays that whenever one quantity of watef is decompofed, ariother equal quantity is compofed in the fame procefsj fo that, as ih« fays, p. r80, " equal quantities are formed and rife re- i( generated like the phenix from her afhes." But this appears to me to be as fanciful, and fabulous, as the fto- ry of the phenix itfelf. 7. From the wonderful experiments that are claffed under the head of Galvanism, it was at firft universally inferred that water was decompofed in fome of the pro- ceffes, becaufe both dephlogifticated and inflammable air were produced in the water that was employed. But it was foon obferved that the dephlogifticated air was no other than that which was drawn from the in- cumbent atmofphere j for if the communication with it F was %i The Doctrine of was cut off, the procefs flopped. Nor were the1 two kinds of air produced in the proportions that the new theory required in the compofition of it ; the dephlo- gifticated air being generally too little for the puv- pofe. From my own experiments on the fubjea, publifh- ed in Mr. Nicholson's Journal, it is evident that the inflammable air muft come from the decompofition of the zinc, which is calcined in the procefs. For when the whole pile was covered with a receiver (landing in water, about one fourth of the inclofed air difappeared, and the remainder was wholly phlogifticated, exaftly as it would have been if a pafte made of iron filings and fulphur had been put in the place of the pile. Had any dephlogifticated air been produced, this could not have been the refult, for that would have kept the inclofed air in the fame ftate with that of the atmofphere, and the quantity would have been increafed, and not diminifh- ed. The dephlogifticated air that difappeared muft have gone into calx of the zinc j but certainly there had been no decompofition of the water. Tho' the doarine of the decompofition of water on the principle of the new theory is fallacious, my expert ments make it exceedingly probable that it is refolva- ble into phlogifticated air, which I fuppofe to confift; of reunion of the two principles of phlogifton and dephlogifticated air. For whenever water is con- verted into vapour, either by means of heat, or in the vacuities of ice by freezing, a portion of this be- comes permanent air, and this is always phlogifticated. For the proof of this I muft here content myfelf with referring Phlogifton eftablifhed. &j Irbffertmgto the account of my experiments relating to the conversion'of witer into air, begun in E .glau-f, and thofe on the freezing of water made in this coun- try* SECTION Xlf. Of the Constitution of Fixed Air\ I Flhave proved that inflammable air comes from the metals, and not from the water in which thb folution of them is made, and that water has not beeri decompofed, fo that it cannot be proved to confift of two kinds of air, I have done all that is rieceffary to ef- tablifh the doarine of phlogiston. There are howevef, two other affumptions in the new theory which 1 think have by no means been proved, viz. that fixed air con- fifts of carbone diflblved in dephlogifticated air, and that phlogifticated air, called azote, is a fimple fub- ftance, and no compound. Is either of thefe luppofiti- ons appear to me to have been proved, and 1 think there is much pofitive evidence againlt them. F U Tho' 84 The Doctrine of Tho' the new theory difcards phlogifton, and ift this refpeais more, fimple than the old, it admits ano- ther new principle, to which its advocates give the name of carbone, which they define to be the fame thing with charcoal, free from earth, falts, and all other ex- traneous fubftances ; and whereas we fay that fixed air confifts of inflammable air and dephlogifticated air, or oxygen, they fay that it confifts of this carbone diffolv- ed in dephlogifticated air. See Examination of Mr. Kirwan, p. 79. Mr. Lavoifier fays, ib. p. 63, that "wherever fixed air has been obtained there is charl «< coal." They therefore call it the carbonic acid. But in many of my experiments large quantities of fixed air have been procured where neither charcoal, nor any thing containing charcoal, was concerned, or none in quantity fufficient to account for it. There is no metal that I have ever heated with a burning lens over lime water in atmofpherical air with- out producing a thick fcum on its furface, which was, no doubt, lime, formed by the quicklime in the water, and the dephlogifticated air contained in the portion of atmofpherical air in which the procefs was made. For this purpofe I have tried not only iron and zinc which are faid to contain plumbago (a kind of carbone from which fome fixed air may be expelled) and alfo lead,, tin, bifmuth, copper, &c. as obferved before, but even gold, filver, and platina,and it will hardly be pretended that all thefe metals contain carbone. From a quantity of calx of lead, part grey and part yellow, in a, glafa tube, I got its bulk of almofl. pure fix- ed • Phtogifton eftablifhed. $$ cd air, and the refiduum extinguifhed a candle. Where could be the carbone in this cafe ? Fixed air is always produced when iron is melted, and thereby converted into finery cinder, in atmofphe- rical or dephlogifticated air, and alfo when fome kinds of inflammable or dephlogifticated air are fired toge- ther. But Mr. Berthollet, Mr. Adet, and all my op- ponents, fay that this fixed air comes from the plumba- go contained in the iron, and that when it is found af- ter the union of inflammable and dephlogifticated air, in an explofion of them, it was from plumbago contain- ed in the inflammable air. But befides that there is no evidence of inflammable air containing any plumbago (fince when iron is diffolved in any acid the plumbago is left behind) the fixed air contained in this fubftance, of which the antiphlogiftians make fo much ufe, is ve- ry inconfiderable ; the air into which it may be refolv- td being chiefly inflammable. From 6 dwts. of the pureft plumbago, procured from an iron furnace, in the form of a fhining black powder, I expelled, in a glazed earthen tube, forty ounce meafures of air, one twelfth part of which was fixed air, and the reft inflammable, burning with a blue flame. Then, fending fteam through the tube, I got two hundred and forty ounce meafures more, the whole ol which was inflammable air, of the pureft kind, exact- ly refembling that from iron by the vitriolic acid. The plumbago was converted into one mafs, refembling a hard cinder, and weighed two dwts and an half. Another experiment on plumbago I fhall juft men- tion in this place. Melting one dwt. of it with a burn- F3 ing 86 The Doctrine of ing lens in the open air, it threw off fparks, like caft iron treated in the fame manner, but not quite fo much; after-which it was reduced to a flag like finery cinder, Weighing four grains lefs than it had done. I repeated, the experiment with the fame reiu't. If plumbago be held in folution in inflammable air, not only muft both he kinds of air contained m it, viz. fixed and infl immab!e,but the slag too, which remains after all air is exoelled from it. But after the explofion which it is laid difc overs the fixed air that was contain- ed in it^ there is no apparent addition made to the in- flammable air, nur the leaft appearance of the slao-. It is evident therefore, that no fuch fubftance was con- tained in the ii.fl .mmable air from any kind of iron, and leaft, of all from malleable iron. „,,if the inflammable air had held in folution not the plumbago itftlf, but only the carbone that was in it, the refiduum could net be plumbago, fince it would want the carbone ; and the inflammable air holding the car- bone in foluth — woul 1 of the heavy, and not of the light- er aP'l purer, kind. Fixed air is alfo produced when minium, and feve- ral other fubftances that contain dephlogifticated air, are heated in inflammable air. This produce I had when i ufed fome precipitate per fe with which Mr. B'■..' hoilet fupplied me. On being informed of this, he faid that he found afterwards, that the precipitate he had ftnt me contained fixed air ; and yet he allowed that when the air expelled from it by heat was received in lime water, it did not immediately make it turbid, which it is well known that a hundredth part of the fix- ed Phlogiston eflabliflied. tj ed air that I procured by means of it would have done inftantly. The turbulency that came on afterwards muft, therefore, have had fome other caufe, probably forne acid of vitriol in the water in which he made the ex- periment, and \viiieh gradually infinuating itfelf into the iime water in his tube, would form selenhe; a thing that has frequently occurred in the courfe of my own experiments, and which for fome time puzzled me not a little. It is genera'ly thought that the fixed air contained in falle .1 lime has been attraaed from the atmofphere, in which it is faid to float in a loofe uncombined ftate. But from no other experiment that I am acquainted w ith can it be proved, that any fixed air neceffarily ex- ifts in the atmofpheric, and lime, or lime water, will become faturated with it in all fituationS. I am there- fore inclined to think that this fixed air is compofed of phlogifton imparted to the lime from the fire to which it had been expofed, and the dephlogifticated air in the atmofphere ; and I have always found that a portion of atmofpherical air expofed, fome time to lime, or to lime water, is fenfibly lefs pure than before ; fome part of the dephlogifticated air of which it is compofed having been taken from it by the lime; and it is never found again except as a component part of the fixed air, which is afterwards expelled from it. The refult of the ex- periment was the fame, whether the lime was confined by water or by mercury. The fixed air wnich is expelled from the yellow calx •f lead which has been fome timeexpofed to the atmof- phere has, I doubt not, the fame fource. For v.hen it F 4 is $3 The Doctrine of is heated prefentJy after it is made, little *r no air cam be expelled from it, as it may fome time afterwards. And I find that this fubftance alfo expofed to a portion of atmofpherical air makes it lefs pure than it was be- fore, juft as in the cafe of quick lime. As pvrophorus imbibes pure air when it is -expofed to atmofpherical air, leaving nothing but phlogifticated air (in which it refembles a mixture of iron filings and fulphur, which alfo makes a pyrophorus) the fixed air expelled from it afterwards muft have been formed by the union of the dephlogifticated air imbibed by it, and the phlogifton contained in itfelf. From a quan ity of old and fpoiled pyrophorus I got or-e hundred and eight)' ounce meafures of air, of the firft part of which one half was fixed air, and the reft phlogifticated. At the lall, tho' one half was fixed air, the reft was inflammable. In another experiment erf this kind 1 found feven tenths of the air fixed, and th* reft inflammable. From 15 dwts. of fallen lime I got forty five ounce measures of fixed air, and twenty five of inflammable. from the gun barrel in which the experiment was mad*; W hether quicklime has been expofed to the atmofphere fo as to become what is called fallen lime, or has been faturated with water, they come in timp to be of the fame weight, and to have the fame properties; the for- mer continually gaining weight, and the latter lofing it. From 15 dwts of lime faturated with water and then expofed to the atmofphere^ I got fifty five ounce. m#afures oi fixed ?ur. *hati Phlogifton eftablifhed. 89 I had a refult fimilar to this when I expofed fome •Id plaister of Pat is to heat in an earthen retort. In (hefe circumftances 3. 25 ounces yielded two hundred ounce meafures of air, of which the firft part contain- ed about one twentieth of its bulk of fixed air, and th© remainder was CKMjfiderabi) phlogifticated, via. of the ftandard of 1. 5, tho' at the laft of 1. 35. It may be faid that pyrophorus attracts water from the atmofphere, and that the water is decompofed by expofure to heat. But in no other cafe is water fo at- traaed decompofed by mere expofure to heat. Wa- ter is attraaed by lime, by vitriolic acid, and various Other fubftances ; but heat will always expel it ag..>, and it may be colleaed in the form of w ter, wi.hout any decompofition. There i6 therefore, ever, r j- £on to conclude that it is the fame with water attracted by pyrophorus. It i?, indeed, an obvious objeaion to the antiphlo- giftic theory, that it fuppofes water to be decompofed tn fuch different circumftances. What can be more fo than when it is applied in the form of fteam to iron red hot, alfo when it is quite cold, and merely prefent in the fame veffel in which the iron, alfo cold, is diffolv- ed by an acid, and by the aaion of light on growing ve- getables, &c. &c. But if inflammable air be procured, the theory abfolutely requires that water be decompo- fed, and no difference of circumftances is fo much as attended to. To thefe experiments relating to fixed air I fhall add one that 1 made on the heating of the diamond in atmofpherical air, much # but in other cafes by means of dephlogifticated air, whe- ther any portion 6f this kind of air be united With it or not. Of this my readers will judge from the experi- ments that I fhall lay before them, 1. One decifive proof that phlogifticated air may be formed, and feemingly by the union of dephlogifticated air and phlogifton, is the quantity of phlogifticated air that remains after any explofion of dephlogifticated or common air with inflammable air, more than what re- mains after the mixture of nitrous air with either of them. Having procured a quantity of dephlogifticated air fo pure that one meafure of it mixed with two meafures of nitrous air was reduced to 0. 04, I could not by any mixture of the pureft inflammable air fired along with it reduce it to lefs than 0. 25. 2. The very different proportions in which atmos- pherical air is diminifhed in different proceffes, is a proof that in fome of them there muft be a generation of phlogifticated air. When air is diminiflied by iron filings and fulphur moiftened with water, the propor- tion of phlogifticated air is that which Mr. Lavoifier flates, viz. 73 parts in 100. But when I made the mix- ture without any water, I found that one hundred mea- fures were in fix days reduced only to ninety complete- ly phlogifticated, which is in the proportion of 81. 8, in 100. Again one hundred and forty ounce meafures were * I am now pretty well satisfied that when inflammable air be- comes phlogisticated air, it gets dephlogisticated air through the watef *)' which it is confined. v< Phlogifton eftablifhed. gg yrere by the fame dry mixture reduced to one hundred and thirteen, which is in the proportion of 80. 6, in 100. But fome water getting to the mixture the third time that it was ufed, one hundred and fifty five ounce meafures of air were reduced by it to one hundred and Gxteen ; which is in the proportion of 74 to iOO. By the flow burning of phofphorus fixty ounce mea- fures of atmofpherical air was reduced to forty eight; at another time to 48. 5 ; and fifty ounce meafures were reduced to forty, which is in the proportion of 80 parts of phlogifticated air in 100. But by repeatedly firing the phofphorus with a burning lens, one hundred ounce meafures were reduced to eighty nine completely phlo- gifticated. Meffrs. Berthollet and Fourcroy however, fay (An- notes de Chymie, Vol. 26, p. 308) « We muft abandon *« the teft of the purity of air by means of nitrous air ; " and fubftitute that of phofphorus, by means of which " we get uniform refults. They are different with ni- " trous air, on account of the different proportions ia " which this, air combines with dephlogifticated air to *' form nitrous acid." But how can thefe proportions vary when the cir- cumftances in which they are mixed are exaaiy the fame ? The nitrous air admitted in the fame manner to any kind of air, containing in it a portion of dephlo- gifticated air, muft unite with this, and this only ; leav- ing the other, with which it cannot combine, as it was * and it requires no particular degree of heat to do this* The refult is, therefore, the fame in all temperatures. On this account it is the moft convenient, and perhaps as $4 *' The Doctrine of as accurate teft as we can apply. It is only neceffafy* that there be a fufficient quantity of nitrous air to fatu- rate all the dephlogifticated air that it can meet withf and that the fame time intervene between the mixture' and t' e meafuring of the dimunkion occafioned by it: The dimunition of atmofpherical air by means Of phof- phorus is both a tedious, and even a lefs certain pro- cefs, as well as attended whh expence j and I find that the ufe of inflammable air inftead of nitrous air, which fome perfons recomme-id, is liable to much greater ob- jeajons, the refult of the firi .g of them by the elearic fp.rk beirg exceedingly various in circumftances as nearly as we can judge the very fame.* 8 SincA * Mr. Rupp also objects to the ure of nitrous air as a test of the- purity of atmospherical air, and quo es a former experiment of mine, ifc which it appeared that by or.l; pouring a mixture of nitrous and atmos- pherical air from one vessel to another, and also by letting the mi*. ture stand some days without any agitation, the degrees of dimunition were very various ; and he says that therefore from the still greater dimunition of 'his mixture which I have since observed, it cannot be concluded that atmospherical air contains more dephlogisticated air thati has hitherto been supposed. I acknowledge that my conclusion from that observation was not just, but for a reason that I was not at that rime acquainted with. For I have since found that not only does that mixture of air continue to diminish still farther by being longer confi- ned by water, but that a q.u.tity of any kind of air will in-time be wholly absoibed in the same circumstances, and that some time before they disappear they all become phlogisticated air, inflammable air ae well as the rest. This is a fact of which I am not able togiv« any rational account, any more than of several others that have fallen under my observation. I have given a detailed account of the facts in an article I lately sent to the philosophical society at Philadelphia, together w ith artbther, on any two kinds of air, separated by an earthen vessel, or a bladder, changing Phlogifton eftablifhed. g$ 3. Since pure nitrous air wholly vanifhes when it unites with pure dephlogifticated air, the phlogifticated air that is found after heating iron in it cannot he a fimple element, but muft have been formed from fome- thing in the nitrous air and phlogifton from the iron. Heating malleable iron in fixty ounce meafures of ni- trous air, it was reduced to twenty four, allphogifticat- ed. When I continued this procefs beyond the point of greateft dimunition, the air produced was inflamma- ble. 4. Since water contains but a fmall quantity of air in propertion to its bulk, and generally confidcrably purer than that of the atmofphere, the phlogifticated air that is produced by heating fteam in a copper vef- fel muft have been formed from phlogifton in the cop- per and the air contained in the wate ; and whenever I have heated water in this manner (the upper part of a clofed copper tube being kept in a red heat, while the lower and open part was imraerfed in water) I have found a confiderable quantity of air completely phlo- gifticated, and the longer I kept it in this ftate the more of this air I found. I had fimilar refults when I ufed a filver tube. That this phlogifticated air is not that which had paffed from the centre of the fire thro' the metal tubes (tho' fome of my late experiments prove that fome me- tals places, which I had observed before with respect to steam and air. This is a fact of great importance in the system of nature, especially with respect to respiration ; but of the cause of it I have not even a conjec- ture worth proposing. Both the above mentioned articles are publish- ed together with others, in the fifth volume of the.Transactions. $6 The Doctrine ef tahj are permeable to air in thefe circum>ftan«es) appears from the refuits or my experiments with glased ear- then tubes in the fame circumftances. For the air that gets into the infide of thefe is often little worfe than atmofpherical air. 5. It is well known that hot eharcoal imbiber any kind of air ; and 1 have obferved that when it is after- wards put into water 't gives this air out again. But if the air be that of the atmofphere, it takes the dephlo- gifticated part in preference to the other, leaving the remainder phlogifticated ; and the air that it gives out after this in water is chiefly phtogiftica'ed. What, then, becomes of the deplogifticated air that has difappear- ed ? Will it be faid that it remains in the charcoal, which had imbibed it ? Whence then came the phlo- gifticated air which it gave out,, when, according to the 1 new theory, charcoal does not contain any fuch princi- ple ? It is not found in the water into which it is put; for this gives out air lefs pure than it did before the procefs. 6. A folution of copper in volatile alkali gave phlo- gifticated air with marine acid, and it will not be eafy to fay where this azote exifted before the procefs. 7. Moft of the fubftances which have been ufed to phlogifticate ah* gain an addition to their weight in the procefs, in confequence of which it has been taken for granted by the antiphlogiftians, that nothing is e- mitted from them, and that they only imbibe the de- phlogifticated air, which is one conftituent part of the atmofphere, leaving the other part, which by call o- zote, unaltered. It was, therefore, defirable to find fome Phlogifton eftablifhed. ^ fome fubftance which would not gain any weight in the procefs, and yet have the fame effea in phlogifticating the air. For the dephlogifticated air not uniting with the fubftance expofed to it muft neceffarily form fame ether combination. This end was in fome meafure anfwered by steel, which, according to the common hypothefis, contain- ing more phlogifton than iron, would, I thought, part with more on the application of heat and receive lefs addition ; and this I found to be the cafe. But it was more completely anfwered by black bones, which with- out gaining an}' thing by the application of heat in any Circumftances, became white in the procefs. If this be done in common air, as the bones do not imbibe the dephlogifticated air that difappears, this air is difpofed of in two different ways. For one part of it contributes to form fixed air, and another part may form a different union with fomething emitted from the bones, and make an addition to the phlogifticated air. * Accordingly, there is more of it found after the pro* cefs with the black bones than with iron, and many o- ther fubftances which receive an addition of weight in i the procefs. Whence, then, I afk, can come this addition of phlogifticated air, but from an union of phlogifton c- mitted from the bones, with the dephlogifticated air in the atmofpherical air to which they are expofed ? Con- fequently phlogifticated air,or azote, is not a fimple fub- ftance, as the antiphlogiftians maintain, but a com- pound. Alfo whence can come the fixed air that is procured in the fame procefs, but from a different com- G bination $8 The Doctrine of bination of the fame elements, and not as they fay from carbone, which is a fubftance of vegetable origin, and has no place here ? Mr. Kupp is of opinion that the fixed air is formed from the carbone in the bone, and the dephlogiftieated air that difappears. But when the heat is applied with care, there is no lofs of weight in the bone ; fo that nothing is driven from it befides the phlogiston, which appears to have no weight at all, or none that we can afcertain. That the thing which conftitutes the blacknefs of the bones is the fame with that which has always been called phlogifton, is evident from its forming inflamma- ble air if there be water to fupply it with a bafis. For I find that if they be heated in phlogifticated air, which cannot by parting with any thing contribute to this whitenefs, they neverthelefs become white ,• the air in which they are heated is increafed in quantity, and this increafe is inflammable air. For thefe experiments I find ivory black, which is the coal of ivory ufed by painters, more convenient than common bones. To prepare this fubftance for the ex- periment, I fill an earthen tube with it, and clofing it with clav, expofe it tor a confiderable time, at leaft a quarter of an hour, to the greateft heat of a fmith's fire, which will expel from it every thing that is volatile ; fo that no heat to whicn 1 can expofe it afterwards will affea it, except by means of fome other fubftance with which that which conftitutes its blacknefs has an affini- ty, and with which it can combine. Heating a quantity of ivory black prepared in this manner in 6. 5 ounce meafures of atmofpherical air, there Phlogifton eftabliffied. n« there wa3 no fenfible change in the quantity; but on examining it, I found in it an ounce meafure of fixed air, and the remainder was completely phlogifticated, which is in the proportion of 84 parts in 100 ; whereas the antiphlogiftians fay that any proportion of atmof- pherical air contains only 73 partsjjn 100 of phlogiftica- ted air. It is evident, alfo, that both thefe fubftances confift of the fame elements, viz. dephlogifticated air and phlogifton. A writer in the Medical and Physical journal, p. 30, finds no produaion of phlogifticated air, but only of fixed air, by heating a black bone in dephlogifticated air, and therefore he concludes that my experiment with atmofpherical air was inaccurate. But he fhould have ufed the fame kind of air that I did. What I have obferved is that fometimes fixed air, atod fometimes phlogifticated air is produced from the fame elements, tho' I have not been able to difcriminate all the cir- cumftances in which one or the other is the refult of their combination. 7. Having made much ufe of a mixture of iron fi- lings and sulphur, for the purpofe of phlogifticating' air, I have always had a large quantity which had been long expofed to the atmofphere, from which it is al- lowed that it attraas nothing befides dephlogifticated air. Of this mixture, become quite dry and brown, three and an half ounces expofed to heat in an earthen tube gave out one hundred and twenty ounce meafures of air, of which about one tenth was fixed air, and the reft almoft wholly phlogifticated. Both thefe kinds of air, therefore, muft confift of dephlogifticated air from G % the ioo The Doctrine of the atmofphere, and fomething contained in the iron, or the fulphur, both of which are maintained to be Am- ple fubftances. There remained a black powder, ftrong- ly attraaed by the magnet. 8-. In general iron filings and fulphur immerfed in mercury or water, or placed in a vacuum, yield in- flammable air ; but in fome cafes (tho' I do not know the reafon of the difference) this mixture has yielded phlogifticated air. Having placed a pot containing fome of this mix- ture in a vacuum, I found after fome days that it had yielded two and an half ounce meafures of air; and examining it, 1 found it to be completely phlogifti- cated. I then put the fame mixture under water, and placing it near the fire, it gave an ounce meafure more| all phlogifticated. At another time two ounce meafures of air were yielded by a mixture of this kind ; and being examin- ed, tho7 not till long after it was formed, it was found to be wholly phlogifticated. It might have been origin- ally inflammable air, and afterwards have changed to phlogifticated. 9. Of the change of inflammable air into phlogiftica- ted air, feveral inftances may be feen in the account of fome of my early experiments j but I am not yet able to fay on what this change depends. Suppofing that it required the union of a portion of dephlogifticated air, I expofed to it pieces of iron, which being covered with raft, had attraaed and contained that air j but the re- fults were not uniform. I fhall, therefore, content myfelf with relating what I obferred, wiflbupg that o- the Phlogifton eftablifhed. lot ther perfons may diverfify the circumftances, and en- deavour to afcertain the caufe of the different refults. Having made a number of pieces of iron rufty bv dipping them in marine acid, I put them imo a glafs veffel which 1 then filled up with mercury, and I dif- placed this mercury by.inflammable air. After waiting about eight months, 1 examined the air, and found it to be very flightly inflammable ,the far greater part of it being evidently phlogifticated air. The iron, from being red, which all antighlogiftiaris will fay was ow- ing to its, containing oxygen, was become black, being covered with a kind of foot, which was wiped off, ftain- ing the fingers and paper. Under this coating the iron was of its ufual colour. Whence, now, came*his phlo- gifticated air, if not from the union of dephlogifticated and inflammable air? This experiment is very little liable to the objeai- onof the Monthly Reviewer, p. 371, as the pieces of iron had not been expofed to the atmofphere any great length of time ; and I am confident that by no procefs whatever could any phlogifticated air have been extraa- •d from them. If the above mentioned black fubftance with which the pieces of iron were coated be plumbago (and of this little doubt can be entertained) it will appear to be a calx of iron fuperfaturated with phlogifton, and that the whole of the iron might have been converted into it; but that plumbago cannot be contained in iron, fo as to yield, on its folution in an acid, the phlogifticated airof which my opponents have endeavoured to avail them- felvea. £ S On loi The Ddctrine tf On the 15th of Auguft 1799, I examined a quantity of inflammable air which had been confined by mercu- ry with dry iron rufted in nitrous acid, from the 18th of March 1798, and found nothing inflammable 'in it, tho' there was no apparent change in the colour of the iron. This was alfo the cafe with another quantity of the fame kind of air which had been confined in the fame manner from the 14th of July. However, ano- ther quantity of inflammable air that had been confined the fame time, and in the fame manner, with iron ruft- ed in vitriolic acid was not much changed, tho' the iron was become black. The CONCLUSION, JDluFORE the new theory of chemiftry pan be unexceptionably eftablifhed, the following things muft be done. 1. Whenever inflammable air, or hydrogen, is pro- cured, evidence muft be given of the produaion of a due proportion of oxygen, that is of 85 parts of this to 15 of the other ; and this evidence muft be fomething more than an addition of weight. It muft be either aaual acidity, or dephlogisticated air. Otherwife there Phlogifton eftablifhed 103 is no proof of the inflammable air having come from the decompofition of the water. This, however, has not been done with refpea to iron, or any other fubftance by means of which inflammable air is procured. 2. When water is procured by the burning of inflam- mable air in the dephlogifticated air, not only muft the water be free from acidity, but there muft have been no produaion of phlogifticated air in the procefs* For by the decompofition of this air the .nitrous acid may be procured. On the whole, I cannot help faying, that it appears to me not a little extraordinary, that a theory fo new, and of fuch importance, overturning every thing that was thought to be the beft eftablifhed in chemif- try, 4 The IXoUrine of of plants in general: yielding de$hldgUtic«t&l zmihy means of light, as well as this property of the green: ye* getable matter in particular, was prior to; that of. Dr. Ingenhomfo. It is well known to all nay friends and acquaintance that I never deferred this method of pub* Hftiing my discoveries* a fingle day, if I had an oppor- tunity of communicating them to others by tfpeaking or writing about them. Befides that this waa always my. natural inclination and habit, I have more than once ob» ferved that the fpeedy communication of d'lfeoveries'is of great importance to the advancement of fcienee^ • The feveral fteps in this invefligation were as foh. lows. In 1772r I found that the growth of plants ref- tored air vitiated by aninaali refpiration. For this dif- covery chiefly I received the gold medal of the. Royal Society ; and Sir John Pringle, in his fpeech on the QO cafion, enlarged on my idea of one part of the creation being the means of repairing the injury done to the at- mofphere by the other. In 1778, being at timingtoo, on the fea more, I found the air in the bladders of the, fea weed to be much purer than that of the. atmofphere, Jn the fame fummer 1 found the air in which fome plants had grown much purer than the external, air, an effect that could not be afcribed to any thing but the produc- tion of dephlogifticated air. And it was at the clofe of the fame year that, obferving bubbles of air emitted by the green- matter with which {the infideoffome of my phials was covered, I examined it, and found it to be highly dephlogifticated. Excluding the light, the pro- duaion of air always ceafed, tho' in the fame de- gree of heat ; fo that the effea was owing to light only. Being Phlogiftdk eftalUfhe$. ± i 5 Being in London the winter following, I fhewed this experiment to all my friends, and among the reft to Dr. Ingenhoufz, who was particularly ftruck with it. The queftion amongft us then was whatthis gran mat- ter could be; and it being generally thought to be a ve- getable, I determined to try the effea of known plants as foon as I Ihould return to the country. According- ly I did fo with the firft fun ihine that I had, and com- pleted the difcovery. But in the mean time Dr. Ingen- houfz anticipated me by his publication, which I think I (hould not have don« with refpect to him, if I had found him in the fame train of inveftigation in which he found me. Such are the fatfs. Let others judge of them as they fee reafon. The ascertaining any perfon's right to the difcoveries he makes is of no farther ufe than as a motive to others ; fhewing them that they will not lofe the fhare of praife to which their fagacity or induftry fhall fairly entitle them. As it is now more than twen- ty years fince the difcovery was made, in all which time Dr. Ingenhoufz has enjoyed the merit of it, I can- not be faid to have fliewn much anxiety about it. Dr. Ingenhoufz in his Essay on the food of plants, p. 2, fpeaks of my " known eagernefs for fame," and alfo that of Mr. Scheele. It has not, however, been ve- ry confpicuous in this bufinefs ; and if it be a fault, I think Dr. Ingenhoufz himfelf will be thought to be as shargeable with it as either of ua. 3. Of Ilfr The Doctrine of 3. Of the Discovery of dephlogisticated Air. INI OW that I am on the fubje& of the right to discoveries, I will, as the Spaniards fay, leave no ink of this kind in my mkhorn ; hoping it will be the lafl time that I fhall have any occaifioh to trouble the public about it. Mr. Lavoifier fays (Elements of Chemistry, Englifh tranflation, p. 36) " this fpecies of air" (meaning de- phlogifticated) «• was difcovered almoft at the fame " time by Mr. Prieftley, Mr. Scheele, and myfelf." The cafe was this. Having made the difcovery fome time before I was in Paris in 1774, I mentioned it at the table of Mr. Lavoifier, when moft of the philofophi- cal people in the city were prefent ; faying that it was a kind of airin 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 Madame Lavoi- fier as much as any, expreffed great furprife. I told them thati had gotten it from precipitate per se, and alfo from red lead. Speaking French very imperfectly, and being little acquainted with the terms of chemiftry, I faidplomb rouge, which was not underftood till Mr. Macquer faid I muft mean minium. Mr. Scheele's dif- covery was certainly independent of mine, tho' I be- live not made quite fo early. 4. Of Phjogiston eftablifhed. 117 4. Of Mr. Humphry Davy's Essays. w HEN fome progrefs was made in printing this work I met with Dr. Beddoes-s Contributi- qns to physical and medical knoxvledge, and in it Mr. H. Davy's Essays, which have impreffed me with a high opinion of his philofophical acumen. His ideas were to me new, and very ftriking, but they are of too great confequence to be decided upon haftily. I wifh fo feemingly accurate an experimenter would repeat, with the attention that he would give to all the circumftanc- es, the French experiment of the compofition of water. I cannot help fufpeaing that his account of it would not be fo very deeifively in favour of their conclufion as theirs. Mr. Davy takes it for granted that water is decom- pofed by the growth of plants, and thinks this to be proved by finding dephlogifticated air produced in this manner in water out of which air had been expelled by boiling, or by the air pump. But he was not aware that water even recently boiled, and examined while warm, contains nearly as much air as it did before boiling, and by no means fo pure ; fo that it can probably fuppl.y more nourifhment to a plant than water which had not been boiled. Air expelled from water by the air pump, pr even the Torricellian vacuum, which does it more effeaually, i-., foon replacetJ by expofure to the atmoL- pheie. Wl:,: 118 The Jhttrim ef . What I complain of in Mr. Davy and many others, is the too hafty introduction of new terms in chemiftry. They perplex thofe who are moft converfant with the fubjea, and are a greatt impednsaentto beginners. For the old language will never be wholly obfolete while old books are read. If the new theory fbouM not ftand its ground, many terms in the new nomenclature muft fall with it. And Mr. Davy's nitrogen, 1 fufpea, will be no longer lived than the French hydrogen. I have myfelf been exceedingly cautious in intro- ducing new terms, and have never done it but when there was an abfolute neceffity to give a name to a fub- ftance that had no name before. Air rendered unfit for refpiration or combuftion, having no name appro- priated to it. J, having frequent occafion to mention it, called it phlogisticated air, becaufe atmofpherical air I found was reduced to that ftate by fubftances containing phlogifton, if there be fuch a thing as phlogifton (which was then univerfally taken for granted) and by no other means. Having afterwards difcovered another kind of air, the properties of which were the reverie of thofe of phlogifticated air, I called it dephlogisticatedair. I alfo introduced the terms nitrous air, dephlogisticated nitrous air, Marine acid air, vitriolic acid air, fluor acid air, alkaline air, and sulfurated inflammable air, denomi* nating them from their fuppofed conftituent parts, or their known properties, and I generally confulted fome philofophical friend before I fixed upon any of them. I faw no occafion for the term gas. becaufe I found '*he termor ufed generically already ; the term fxed air and inflammable air, as well as atmospherical air br- ing Phlogiston eftablifhed. 119 lag in ufe before.- If we want an adjecYive, the aerial form, of a fubftance will do as well as the gazeousform j and Mr. Davy, w ho, introduces the term gazity to ex- prefs the abftraa idea in the fubftatvtive form, might have made as good a word of a fimilar fignification from BTTHE AUTHOR OF THIS TRACT. A HE Hiftory and prefent ftate of Electri. city, with original Experiments, illuftratsd with Cop- per Plates, 5th Edition, corrected, It is. in boards; 2. A Familiar Introduction to the Study of Electri- city, Sth Edition, 8ro. 2s. 6d. fewed. 3. The Hiftory and prefent State of Discoveries re- lating to Vision^ Light, and Colours, 2 vols, 4to, illuf- "tratedwith a great number of Copper Plates, ll. lis*, 6d. inbds. ll. 18s. bd. 4. 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