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 ELEMENTS 
 
 f> 9 
 
 CHEMISTRY. 
 
E 1 E M E n't S 
 
 O F 
 
 C H E M I S T *R y ; 
 
 IN A 
 
 N E W ' & Y S T E M A TI C "ORDER. 
 
 CONTAINING ALL THE 
 
 - \ + 
 
 modern discoveries. 
 
 ILLUSTRATED WITH THIRTEEN COPPERPLATES. 
 
 By Mr LAVOISIER, 
 
 ^Member of the Academy of Sciences, Royal Society of Me* 
 dicine, and Agricultural Society of Paris, of the Royal 
 Society of London, and Philofophical Societies 
 of Orleans, Bologna, Bafil, Philadelphia, 
 Haerlem, Manchelter, &c. &c. 
 
 TRANSLATED FROM THE FRENCH, 
 
 By ROBERT KERR, F.R.&A.SS.E. 
 
 Member of the Royal College of Surgeons, and Surgeon 
 to the Orphan Hofpital of Edinburgh, 
 
 EDINBURGH: 
 printed for WILLIAM CREECH, and sold in 
 
 LONDON BY G. G. AND J. J. ROBINSONS* 
 
 M D C C X C. 
 
advertisement 
 
 OF THE 
 
 • translator. 
 
 T H E very high character of Mr Lavoifier 
 as a chemical philofopher, and the great 
 re' elution which; in the opinion of many ex- 
 cellent chemifts, he has effe&ed in the theory of 
 chemiftry, has long made it much defired to 
 have a conneded account of his difeoveries, and 
 of the new theory he has founded upon the mo- 
 dern experiments written by himfelf. This is 
 now accomplilhed by the publication of his 
 Elements of Chemiftry ; therefore no excufe 
 can be at all neceflary for giving the following 
 work to the public in an Englifh drefs ; and the 
 only hefitation of the Tranflator is with regard 
 to his own abilities for the talk. He is mofl 
 ready to confefs, that his knowledge of the 
 compofition of language fit for publication is far 
 
 inferior 
 
VI 
 
 ADVERTISEMENT. 
 
 inferior to his attachment to the fubjed, and to 
 his defire of appearing decently before the judg- 
 ment of the world. 
 
 He has earneftly endeavoured to give the 
 meaning of the Author with the moft fcrupu- 
 lous fidelity, having paid infinitely greater at- 
 tention to accuracy of tranflation than to ele- 
 gance of flile. This laft indeed, had he even, 
 by proper labour, been capable of attaining, he 
 has been obliged, for very obvious reafons, to 
 negled, far more than accorded with his wifnes. 
 The French copy did not reach his hands be- 
 fore the middle of September ; and it was judg- 
 ed necefiary by the Publifher that the Tranfla- 
 tion fhould be ready by the commencement of 
 the Univerfity Sefiion at the end of October. 
 
 He at firfl intended to have changed all the 
 weights and meafures ufed by Mr Lavoifier into 
 their correfpondent Englifh denominations, but, 
 upon trial, the tafk was found infinitely too 
 great for the time allowed ; and to have execu- 
 ted this part of the work inaccurately, muff have 
 been both ufelefs and mifleading to the reader. 
 All that has been attempted in this way is ad- 
 ding, between brackets ( ), the degrees of Fa- 
 hrenheit's 
 
ADVERTISEMENT. Vii 
 
 hrenheit’s fcale correfponding with thofe of 
 Reaumeur's thermometer, which is ufed by the 
 Author. Rules are added, however, in the 
 Appendix, for converting the French weights 
 and meafures into Englifh, by which means the 
 reader may at any time calculate fuch quantities 
 as occur, when defirous of comparing Mr La- 
 voifier’s experiments with thofe of Britilh au* 
 thors. 
 
 By an overfight, the firfl part of the tranfla- 
 tion went to prefs without any diftin&ion being 
 preferved between charcoal and its fimple ele- 
 mentary part, which enters into chemical com- 
 binations, efpecially with oxygen or the acidi- 
 fying principle, forming carbonic acid. This 
 pure element, which exifts in great plenty in 
 well made charcoal, is named by Mr Lavoifier 
 carbone , and ought to have been fo in the tran- 
 flation ; but the attentive reader can very eafily 
 re&ify the miftake. There is an error in Plate 
 XI. which the engraver copied ftricily from the 
 original, and which was not difcovered until the 
 plate was worked off at prefs, when that part of 
 the Elements which treats of the apparatus there 
 reprefented came to be tranflated. The two 
 tubes 2i, and 24. by which the gas is conveyed 
 
 into 
 
Viii ADVERTISEMENT , 1 
 
 Into the bottles of alkaline folution 22. 
 fhould have been made to dip into the liquor, 
 while the other tubes 23. and 26 . which carry 
 off the gas, ought to have been cut off fome 
 way above the furface of the liquor in the bot- 
 ties. 
 
 A few explanatory notes are added ; and in- 
 deed, from the perfpicuity of the Author, very 
 few were found necelfary. In a very fmall 
 number of places, the liberty has been taken of 
 throwing to the bottom of the page, in notes, 
 fome parenthetical expreffions, only relative to 
 the fubjeft, which, in their original place, tend- 
 ed to confute the fenfe. Thefe, and the ori- 
 ginal notes of the Author, are diftinguifhed by 
 the letter A, and to the few which the Tranfla- 
 tor has ventured to add, the letter E is fub- 
 joined. 
 
 Mr Lavoifier has added, in an Appendix, fe- 
 veral very ufeful Tables for facilitating the cal- 
 culations now necefiary in the advanced (late of 
 modern chemiitry, wherein the mod fcrupulous 
 accuracy is required. It is proper to give fome 
 account of thefe, and of the reafons for omit- 
 ting feveral of them. 
 
 No. 
 
ADVERTISEMENT. IK 
 
 No. I. of the French Appendix is a Table for 
 converting ounces, gros, and grains, into the deci- 
 mal fractions of the French pound ; and No.II. for 
 reducing thefe decimal fractions again into the 
 vulgar fubdivifions. No. III. contains the num- 
 ber of French cubical inches and decimals which 
 correfpond to a determinate weight of water. 
 
 The Tranflator would mod readily have con- 
 verted thefe Tables into Englifli weights and 
 meafures ; but the neceflary calculations mull 
 have occupied a great deal more time than could 
 have been fpared in the period limited for pu- 
 blication. They are therefore omitted, as alto- 
 gether ufelefs, in their prefent date, to the Bri- 
 tifh chemid. 
 
 No. IV. is a Table for converting lines or 
 twelfth parts of the inch, and twelfth parts of 
 lines, into decimal fra&ions, chiefly for the pur- 
 pofe of making the neceflary corre&ions upon 
 the quantities of gafles according to their baro- 
 metrical preflure. This can hardly be at all 
 ufeful or neceflary, as the barometers ufed in 
 Britain are graduated in decimal fra&ions of the 
 inch, but, being referred to by the Author in 
 
 b the 
 
ADVERTISEMENT. 
 
 a 
 
 the text, it has been retained, and is No. i. of 
 the Appendix to this Tranflation. 
 
 No. V. Is a Table for converting the ob- 
 ferved heights of water within the jars ufed in 
 pneumatO'Chemical experiments into correfpon- 
 dent heights of mercury for correcting the vo- 
 lume of gaffes. This, in Mr Lavoifier’s Work, 
 is expreffed for the water in lines, and for the 
 mercury in decimals of the inch, and confe- 
 quently, for the reafons given refpeCting the 
 Fourth Table, mu ft have been of no ufe. The 
 Tranflator has therefore calculated a Table for 
 this correction, in which the water is expreffed 
 in decimals, as well as the mercury. This Table 
 is No. II. of the Englifh Appendix. 
 
 No. VI. contains the number of French cubi* 
 cal inches and decimals contained in the corre- 
 fponding ounce-meafures ufed in the experiments 
 of our celebrated countryman Dr Prieftley. 
 This Table, which forms No. III. of the Englifh 
 Appendix, is retained, with the addition of a 
 column, in which the correfponding Englifh 
 cubical inches and decimals are expreffed. 
 
 No. 
 
ADVERTISEMENT. 
 
 xl 
 
 No. VII. Is a Table of the weights of a cubi- 
 cal foot and inch, French meafure, of the dif- 
 ferent gaffes expreffed in French ounces, gros, 
 grains, and decimals. This, which forms No. VI. 
 of the Englifh Appendix, has been, with confi- 
 derable labour, calculated into Englifh weight 
 and meafure. 
 
 No. VIII. Gives the fpecific gravities of a 
 great number of bodies, with columns, con- 
 taining the weights of a cubical foot and inch, 
 French meafure, of all the fubflances. The fpe- 
 cific gravities of this Table, which is No. VII. 
 of the Englifh Appendix, are retained, but the 
 additional columns, as ufelefs to the Britifh phi- 
 lofopher, are omitted ; and to have converted 
 thefe into Englifh denominations mufl have re- 
 quired very long and painful calculations. 
 
 Rules are fubjoined, in the Appendix to this 
 tranflation, for converting all the weights and 
 meafures ufed by Mr Lavoifier into correfpon- 
 ding Englifh denominations ; am' the Tranflator 
 is proud to acknowledge his obligation to the 
 learned Profeffor of Natural Philofophy in the 
 Univerfity of Edinburgh, who kindly flip: died 
 him with the neceffary information for this pur- 
 pofe. A Table is likewife added, No. IV. of 
 
 the 
 
advertisement. 
 
 • • 
 
 Xll 
 
 the Englifli Appendix, for converting the de- 
 grees of Reaumeur’s fcale ufed by Mr Lavoifier 
 into the correfponding degrees of Fahrenheit, 
 which is univerfally employed in Britain *. 
 
 This Tranflation is fent into the world with 
 the utmoft diffidence, tempered, however, with 
 this confolation, that, though it muft fall greatly 
 fhort of the elegance, or even propriety of lan- 
 guage, which every writer ought to endeavour to 
 attain, it cannot fail of advancing the interefts of 
 true chemical fcience, by diffeminating the accu- 
 rate mode of analyfis adopted by its juftly celebra- 
 ted Author. Should the public call for a fecond 
 edition, every care ffiall be taken to correct the 
 forced imperfections of the prefent tranflation, 
 and to improve the work by valuable additional 
 matter from other authors of reputation in the 
 feveral fubjeCts treated of. 
 
 Edinburgh, ? 
 
 Oft. 23.1789. 3 
 
 * The Tranflator has fince been enabled, by the kind 
 afliftance of the gentleman above alluded to, to give 
 Tables, of the fame nature with thofe of Mr Lavoifier, 
 for facilitating the calculations of the rcfults of chemi- 
 cal experiments. 
 
R E F A C 
 
 E 
 
 P 
 
 0 F THE 
 
 author; 
 
 W HEN I began the following Work, my 
 only object was to extend and explain 
 more fully the Memoir which I read at the pu- 
 blic meeting of the Academy of Sciences in the 
 month of April 1787, on the neceflity of re- 
 forming and completing the Nomenclature of 
 Chemiftry. While engaged in this employment, 
 I percei d, better than I had ever done before, 
 the juft ice of the following maxims of the Abbe 
 de Condillac, in his Syftem of Logic, and fome 
 other of his works* 
 
 “ We think only through the medium of 
 £C words* — Languages are true analytical me* 
 « “ thods# 
 
xiv 
 
 PREFACE* 
 
 <c thods. — Algebra, which is adapted to its pur- 
 « pofe in every fpecies of expreflion, in the 
 <c mod fimple, mod exad, and bed manner 
 <c poffible, is at the fame time a language and 
 “ an analytical method. — The art of reafoning 
 cc is nothing more than a language well aran- 
 « ged.” 
 
 Thus, while I thought myfelf employed only 
 in forming a Nomenclature, and while I propo- 
 fed to myfelf nothing more than to improve the 
 chemical language, my work transformed itfelf 
 by degrees, without my being able to prevent 
 it, into a treatife upon the Elements of Che- 
 midry. 
 
 The impofiibility of feparating the nomen- 
 clature of a fcience from the fcience itfelf, is 
 owing to this, that every branch of phyfical fci- 
 ence mud confid of three things $ the feries of 
 fads which are the objeds of the fcience, the 
 ideas which reprefent thefe fads, and the words 
 by which thefe ideas are expreffed. Like three 
 impreffions of the fame feal, the word ought to 
 produce the idea, and the idea to be a pidure of 
 the fad. And, as ideas are preferved and com- 
 municated by means of words, it neceffarily fol- 
 lows 
 
PREFACE. 
 
 m 
 
 lows that we cannot improve the language of 
 any fcience without at the fame time improving 
 the fcience itfelf ; neither can we, on the other 
 hand, improve a fcience, without improving the 
 language or nomenclature which belongs to it. 
 However certain the fads of any fcience may 
 be, and, however juft the ideas we may have 
 formed of thefe fads, we can only communicate 
 falfe impreflions to others, while we want words 
 by which thcie may be properly expreffed. 
 
 To thofe who will confider it with attention, 
 the firft part of this treatife will a nor a i equeiit 
 proofs of the truth of the above obferyations. 
 But as, in the condud of my work, I have been 
 obliged to obferve an order of arrangement ef- 
 fentially differing from what has been adopted 
 in any other chemical work yet publi/hed, it is 
 proper that I fliould explain the motives which 
 have led me to do fo. 
 
 It is a maxim univerfally admitted in geome- 
 try, and indeed in every branch of knowledge, 
 that, in the progrefs of inveftigation, [we fhould 
 proceed from known fads to what is unknown. 
 In early infancy, our ideas fpring from our 
 wants 5 the fenfation of want excites the idea of 
 
 the 
 
PREFACE, 
 
 2Vf 
 
 the obje£t by which it is to be gratified. In 
 this manner, from a feries of fenfations, obfer- 
 vations, and analyfes, a fucceflive train of ideas 
 arifes, fo linked together, that an attentive ob- 
 ferver may trace back to a certain point the 
 order and connexion Of the whole fum of hiu 
 man knowledge. 
 
 When we begin the ftudy of any fcience, we 
 are in a fituation, refpedting that fcience, fimi- 
 lar to that of children ; and the courfe by which 
 we have to advance is precifely the fame which 
 Nature follows in the formation of their ideas. 
 In a child, the idea is merely an effeft produced 
 by a fenfation ; and, in the fame manner, in 
 commencing the ftudy of a phyfical fcience, we 
 ought to form no idea but what is a necefiary 
 confequence, and immediate efiedt, of an expe- 
 riment or obfervation. Befides, he that enters 
 upon the career of fcience, is in a lefs advanta- 
 geous fituation than a child who is acquiring 
 his firft ideas. To the child. Nature gives va- 
 rious means of re&ifying any miftakes he may 
 commit refpedting the falutary or hurtful quali- 
 ties of the objedls which furround him. On e- 
 very occafion his judgments are corredted by 
 experience 5 want and pain are the necefiary 
 
 con* 
 
PREFACE. xvii 
 
 €onfequences arifing from falfe judgment ; gra- 
 tification and pleafure are produced by judging 
 aright. Under fuch mailers, we cannot fail to 
 become well informed ; and we foon learn to 
 reafon juftly* when want and pain are the ne- 
 cefiary confequences of a contrary condud. 
 
 In the fludy and pradice of the fciences it is 
 quite different ; the falfe judgments we form 
 neither affed our exigence nor our welfare ; and 
 we are not forced by any phyfical necefiity to 
 corred them. Imagination, on the contrary, 
 which is ever wandering beyond the bounds of 
 truth, joined to felf-love and that felf- confidence 
 we are fo apt to indulge, prompt us to draw 
 conclufions which are not immediately derived 
 from fads \ fo that we become in fome meafure 
 interefled in deceiving ourfelves. Hence it is 
 by no means to be wondered, that, in the fcience 
 of phyfics in general, men have often made fup- 
 pofitions, inflead of forming conclufions. Thefe 
 fuppofitions, handed down from one age to an- 
 other, acquire additional weight from the autho- 
 rities by which they are fupported, till at laft 
 they are received, even by men of genius, as 
 fundamental truths. 
 
 c 
 
 The 
 
% 
 
 xviii PREFACE* 
 
 The only method of preventing fuch errors 
 from taking place, and of corre&ing them when 
 formed, is to reftrain and fimplify our reafoning 
 as much as poflibie. This depends entirely up- 
 on ourfelves, and the negleft of it is the only 
 fource of our miftakes. We mull truft to no- 
 thing but fa&s : Thefe are prefented to us by 
 Nature, and cannot deceive. We ought, in 
 every inftance, to fubmit our reafoning to the 
 teft of experiment, and never to fearch for truth 
 but by the natural road of experiment and ob- 
 fervation. Thus mathematicians obtain the fo- 
 lution of a problem by the mere arrangement 
 of data, and by reducing their reafoning to fuch 
 fimple fteps, to conclufions fo very obvious, as 
 never to lofe fight of the evidence which guides 
 them. 
 
 Thoroughly convinced of thefe truths, 1 have 
 impofed upon myfelf, as a law, never to ad- 
 vance but from what is known to what is un- 
 known ; never to form any conclulion which is 
 not an immediate confequence neceflarily flow- 
 ing from obfervation and experiment ; and al- 
 ways to arrange the facts, and the conclufions 
 which are drawn from them, in fuch an order 
 as fhall render it molt eafy for beginners in the 
 
 ftudy 
 
PREFACE. xix 
 
 ftudy of chemiftry thoroughly to underftand 
 them. Hence I have been obliged to depart 
 from the ufual order of courfes of lectures and 
 of treatifes upon chemiftry, which always af- 
 fume the firfl principles of the fcience, as known, 
 when the pupil or the reader fhould never be 
 fuppoled to know them till they have been ex- 
 plained in fubfequent leffons. In almoft every 
 inftance, thefe begin by treating of the elements 
 of matter, and by explaining the table of affini- 
 'ties, without confidering, that, in fo doing, they 
 mult bring the principal phenomena of chemiftry 
 into view at the very outfet : They make ufe of 
 terms which have not been defined, and fuppofe 
 the fcience to be underftood by the very perfons 
 they are only beginning to teach. It ought 
 likewife to be confidered, that very little of che- 
 miftry can be learned in a firfl courfe, which is 
 hardly fufficient to make the language of the 
 fcience familiar to the ears, or the apparatus 
 familiar to the eyes. It is almoft impoftible to 
 become a chemift in lefs than three or four years 
 of conftant application. 
 
 Thefe inconveniencies are occafioned not fo 
 much by the nature of the fubject, as by the 
 method of teaching it ; and, to avoid them, I 
 
 was 
 
XX P R E F ACE. 
 
 was chiefly induced to adopt a new arrangement 
 of chemiftry, which appeared to me more con- 
 fonant to the order of Nature, I acknowledge, 
 however, that in thus endeavouring to avoid 
 difficulties of one kind, I have found myfelf in- 
 volved in others of a different fpecies, fome of 
 which I have not been able to remove ; but I 
 am perfuaded, that fuch as remain do not arife 
 from the nature of the order I have adopted, 
 but are rather confequences of the imperfection 
 under which chemiftry ftill labours. This fcience 
 {till has many chafms, which interrupt the feries 
 of fads, and often render it extremely difficult 
 to reconcile them with each other : It has not, 
 like the elements of geometry, the advantage of 
 being a complete fcience, the parts of which are 
 all clofely connected together : Its adual pro- 
 grefs, however, is fo rapid, and the fads, under 
 the modern dodrine, have aflumed fo happy an 
 arrangement, that we have ground to hope, even 
 in our own times, to fee it approach near to the 
 higheft ftate of perfedion of which it is fufcep- 
 tible. 
 
 The rigorous law from which I have never 
 deviated, of forming no conclufions which are 
 not fully warranted by experiment, and of never 
 
 fupplying 
 
PREFACE. 
 
 xx 
 
 Epplying the abfence of faCts, has prevented 
 me from comprehending in this work the branch 
 of chemiftry which treats of affinities, although 
 it is perhaps the befl calculated of any part of 
 chemiftry for being reduced into a completely 
 fyftematic body. Meflrs GeofFroy, Gellert, Berg- 
 man, Scheele, De Morveau, Kirwan, and many 
 others, have collected .a number of particular 
 fads upon this EbjeCt, which only wait for a 
 proper arrangement ; but the principal data are 
 ftill wanting, or, at leaft, thofe we have are either 
 not Efficiently defined, or not Efficiently pro- 
 ved, to become the foundation upon which to 
 build fo very important a branch of chemiftry. 
 This fcience of affinities, or elective attractions, 
 holds the fame place with regard to the other 
 branches of chemiftry, as the higher or tranfcen- 
 dental geometry does with refpeCt to the fimpler 
 and elementary part ; and I thought it improper 
 to involve thofe fimple and plain elements, which 
 I flatter myfelf the greateft part of my readers 
 will eafily underftand, in the obfcurities and 
 difficulties which ftill attend that other very ufe- 
 ful and neceflary branch of chemical fcience. 
 
 Perhaps a fentiment of felf-love may, without 
 my perceiving it, have given additional force to 
 
 thefe 
 
XXII 
 
 PREFACE. 
 
 thefe reflexions. Mr de Morveau is at prefent 
 engaged in publifliing the article djjinity in the 
 Methodical Encyclopedia ; and I had more rea- 
 fons than one to decline entering upon a work 
 in which he is employed. 
 
 It will, no doubt, be a matter of furprife, that 
 in a treadle upon the elements of chemiftry, 
 there fhould be no chapter on the conftituent 
 and elementary parts of matter ; but I fliall take 
 cccaflon, in this place, to remark, that the fond- 
 nefs for reducing all the bodies in nature to 
 three or four elements, proceeds from a preju- 
 dice which has defcended to us from the Greek 
 Philofophers. The notion of four elements, 
 which, by the variety of their proportions, com- 
 pofe all the known fubftances in nature, is a 
 mere hypothefis, aflfumed long before the firfl: 
 principles of experimental philofophy or of che- 
 miitry had any exiftence. In thofe days, without 
 pofiefling facts, they framed fyftems ; while we, 
 who have collected facts, feem determined to re- 
 ject them, when they do not agree with our 
 prejudices. The authority of thefe fathers of hu- 
 man philofophy ftill carry great weight, and 
 there is reafon to fear that' it will even bear hard 
 upon generations yet to come. 
 
 It 
 
PREFACE. xxiii 
 
 It is very remarkable, that, notwithftanding 
 of the number of philofophical chemifts who 
 have fupported the do&rine of the four elements, 
 there is not one who has not been led by the 
 evidence of fads to admit a greater number of 
 elements into their theory. The firft chemifts 
 that wrote after the revival of letters, confider- 
 ed fulphur and fait as elementary fubftances en- 
 tering into the compofition of a great number 
 of fubftances ; hence, inftead of four, they ad* 
 mitted the exigence of fix elements. Beecher 
 affumes the exigence of three kinds of earth, 
 from the combination of which, in different pro- 
 portions, he fuppofed all the varieties of metal- 
 lic fubftances to be produced. Stahl gave a 
 new modification to this fyftem ; and fucceed- 
 ing chemifts have taken the liberty to make or 
 to imagine changes and additions of a fimilar 
 nature. All thefe chemifts were carried along 
 by the influence of the genius of the age in 
 which they lived, which contented itfelf with 
 affertions without proofs ; or, at leaft, often ad- 
 mitted as proofs the flighted degrees of proba- 
 bility, unfupported by that ftridly rigorous ana- 
 lyfis required by modern philofophy. 
 
 All 
 
PREFACE, 
 
 x&iv 
 
 All that can be faid upon the number and 
 nature of elements is, in my opinion, confined 
 to difcuffions entirely of a metaphyfical nature. 
 The fubjed only furnifhes us with indefinite 
 problems, which may be folved in a thoufand 
 different ways, not one of which, in all probabi- 
 lity, is confident with nature. I fhall therefore 
 only add upon this fubjed, that if, by the term 
 elements , we mean to exprefs thofe fimple and 
 indivifible atoms of which matter is compofed, 
 it is extremely probable we know nothing at all 
 about them ; but, if we apply the term elements , 
 or principles of bodies , to exprefs our idea of the 
 lad point which analyfis is capable of reaching, 
 w^e mud admit, as elements, all the fubdances 
 into which we are capable, by any means, to 
 reduce bodies by decompofition. Not that we 
 are entitled to affirm, that thefe fubdances we 
 confider as fimple may not be compounded of 
 two, or even of a greater number of principles ; 
 but, fince thefe principles cannot be feparated, 
 or rather fince we have not hitherto difcovered 
 the means of feparating them, they ad with re- 
 gard to us as fimple fubdances, and we ought 
 never to fuppofe them compounded until expe- 
 riment and obfervation has proved them to be 
 fo. 
 
 The 
 
PREFACE. 
 
 XXV 
 
 The foregoing reflexions upon the progrefs 
 of chemical ideas naturally apply to the words 
 by which thefe ideas are to be expreffed. Guided 
 by the work which, in the year 1787, Meffrs 
 de Morveau, Berthollet, de Fourcroy, and I 
 compofed upon the Nomenclature of Chemiftry, 
 I have endeavoured, as much as poflible, to de- 
 nominate Ample bodies by Ample terms, and I 
 was naturally led to name thefe Arfh It will be 
 recolleXed, that we were obliged to retain that 
 name of any fubftance by which it had been 
 long known in the world, and that in two cafes 
 only we took the liberty of making alterations ; 
 Arft, in the cafe of thofe which were but newly 
 difcovered, and had not yet obtained names, or 
 at lead which had been known but for a fhort 
 time, and the names of which had not yet re- 
 ceived the fanXion of the public and, fecond- 
 ly, when the names which had been adopted, 
 whether by the ancients or the moderns, appear- 
 ed to us to exprefs evidently falfe ideas, when 
 they confounded the fubftances, to which they 
 were applied, with others poffeffed of different, 
 or perhaps oppofite qualities. We made no 
 fcruple, in this cafe, of fubftituting other names 
 in their room, and the greateft number of thefe 
 were borrowed from the Greek language. We 
 d endeavoured 
 
PREFACE. 
 
 xxvi 
 
 endeavoured to frame them in fuch a manner 
 as to exprefs the mod general and the mod 
 chara&eriftic quality of the fubftances ; and this 
 was attended with the additional advantage both 
 of affifting the memory of beginners, who find 
 it difficult to remember a new word which has 
 no meaning, and of accuftoming them early to 
 admit no word without connecting with it fome 
 determinate idea. 
 
 * 
 
 To thofe bodies which are formed by the 
 union of feveral fimple fubftances we gave new 
 names, compounded in fuch a manner as the 
 nature of the fubftances directed ; but, as the 
 number of double combinations is already very 
 confiderable, the only method by which we 
 could avoid confufion, was to divide them into 
 claffes. In the natural order of ideas, the name 
 of the clafs or genus is that which expreffes 
 a quality common to a great number of indi- 
 viduals : The name of the fpecies, on the con- 
 trary, expreffies a quality peculiar to certain in- 
 dividuals only. 
 
 Thefe diftin&ions are not, as fome may ima- 
 gine, merely metaphyfical, but are eftabliffied 
 by Nature. “ A child,” fays the Abbe de Con- 
 dillac, 
 
PREFACE. 
 
 xxvii 
 
 ilillac, 44 is taught to give the name tree to the 
 44 firft one which is pointed out to him. lhe 
 44 next one he fees prefents the lame idea, and 
 44 he gives it the fame name. This he does like- 
 44 wife to a third and a fourth, till at iail the 
 u word tree, which he firft applied to an indi- 
 46 vidual, comes to be employed by him as. the 
 46 name of a clafs or a genus, an abftradt idea, 
 <c which comprehends all trees in general. But, 
 44 when he learns that all trees ferve not the 
 £C fame purpofe, that they do not all produce 
 44 the fame kind of fruit, he will foon learn to 
 44 diftinguifh them by fpecific and particular 
 44 names.” This is the logic of all the fciences, 
 and is naturally applied to chemiftry. 
 
 The acids, for example, are compounded of 
 two fubflances, of the order of thofe which we 
 confider as fimple ; the one conftitutes acidity, 
 and is common to all acids, and, from this fub- 
 ftance, the name of the clafs or the genus ought 
 to be taken ; the other is peculiar to each acid, 
 and diftinguifhes it from the reft, and from this 
 fubftance is to be taken the name of the fpecies. 
 But, in the greateft number of acids, the two 
 conftituent elements, the acidifying principle, 
 
 and 
 
xxviii PREFACE. 
 
 ana th t which it acidifies, may exift in different 
 proportions, conflituting ail the poffible points 
 of equilibrium or of facuration. This is the cafe 
 in the i: • curie and the fulphurous acids ; and 
 
 thefe two dates of the fame acid we have mark- 
 ed by varying the termination of the fpecific 
 name. 
 
 Metallic fubftances which have been expofed 
 to the joint adlion of the air and of fire, lofe 
 their metallic luftre, increafe in weight, and af- 
 fume an earthy appearance. In this date, like 
 the acids, they are compounded of a principle 
 which is common to all, and one which is pecu- 
 liar to ea-:h. In the lame way, therefore, we 
 have thought proper to clafs them under a ge- 
 neric name, derived from the common prin- 
 ciple ; for which purpofe, we adopted the term 
 qxyd ; and we diftinguifh them from each other 
 by the particular name of the metal to which 
 each belongs. 
 
 Cou*buftible fubftances, which in acids and 
 metallic oxyds are a fpecific and particular prin- 
 ciple, are capable of becoming, in their turn, 
 common principles of a great number of fub- 
 ftances. The fulphurous combinations have 
 
 been 
 
PREFACE. 
 
 XX13C 
 
 been long the only known ones in this kind. 
 Now, however, we know, from the experiments 
 of Mefifrs Vandermonde, Monge, and Berthok 
 let, that charcoal may be combined with iron, 
 and perhaps with feveral other metals ; and that, 
 from this combination, according to the propor- 
 tions, may be produced fteel, plumbago, &c„ 
 We know likewife, from the experiments of 
 Pelletier, that phofphorus may be combined 
 a great number of metallic fubftance^ I„ . e 
 different combinations we have clafled under 
 generic names taken from the common fub- 
 ftance, with a termination which marks this 
 analogy, fpecifying them by another name taken 
 from that fubftance which is proper to each. 
 
 The nomenclature of bodies compounded of 
 three fimple fubftances was attended with fliil 
 greater difficulty, not only on account of their 
 number, but, particularly, becaufe we cannot 
 exprefs the nature of their conftituent principles 
 without employing more compound names. In 
 the bodies which form this clafs, fuch as the 
 neutral falts, for inftance, we had to confider, 
 lft, The acidifying principle, which is common 
 to them all \ 2d, The acidifiable principle which 
 conflitutes their peculiar acid \ 3d, The faline, 
 
 earthy, 
 
XXX 
 
 PREFACE. 
 
 earthy, or metallic bafts, which determines the 
 particular fpecies of fait. Here we derived the 
 name of each clafs of faits from the name of the 
 acidifiable principle common to all the indivi- 
 duals of that clafs ; and diftinguifhed each fpe- 
 cies by the name of the faline, earthy, or metal- 
 lic bafis, which is peculiar to it. 
 
 A fait, though compounded of the fame three 
 principles, may, neverthelefs, by the mere diffe- 
 rence of their proportion, be in three different 
 fhtes. The nomenclature we have adopted 
 would have been defective, had it not expreffed 
 thde different ftates ; and this we attained chief- 
 ly by changes of termination uniformly applied 
 to the fame ftate of the different faits. 
 
 In ftiort, we have advanced fo far, that from 
 the name alone may be inftantly found what 
 the combuftibie fubftance is which enters into 
 any combination ; whether that combuftibie fub- 
 ftance be combined with the acidifying principle, 
 and in what proportion ; what is the ftate of the 
 acid ; with what bafts it is united ; whether the 
 faturation be exaft, or whether the acid or the 
 bafis be in excefs. 
 
 It 
 
P R E F A C E» Xxxi 
 
 ft may be eafily fuppofed that it was not pof- 
 fible to attain all thefe different objeds without 
 departing, in fome inftances, from eftabiifhed 
 cuftom, and adopting terms which at firfl fight 
 will appear uncouth and barbarous. But we 
 confidered that the ear is foon habituated to 
 new words, efpecially when they are connected 
 with a general and rational fyftem. The names, 
 befides, which were formerly employed, fuch as 
 powder of algaroth , fait of alembroth , pompholix % 
 phagadenic water , turbith mineral, colcothar and 
 many others, were neither lefs barbarous nor 
 lefs uncommon. It required a great deal of 
 pradice, and no fmall degree of memory , to re- 
 coiled the fubftances to which they were applied,, 
 much more to recoiled the genus of combina- 
 tion to which they belonged. The names of 
 oil of tartar per deliquium , oil of vitriol , butter of 
 arfenic and of antimony , flowers of zinc , &c. were 
 (fill more improper, becaufe they fuggefted falfe 
 ideas : For, in the whole mineral kingdom, and 
 particularly in the metallic clafs, there exifls no 
 fuch thing as butters, oils, or flowers; and, in. 
 fhort, the fubftances to which they give thefe fal- 
 lacious names, are nothing lefs than rank poifons* 
 
 When. 
 
sxxii preface; 
 
 When we publifhed our effay on the nomen- 
 clature of chemiftry, we were reproached for 
 having changed the language which was fpoken 
 by our matters, which they diftinguifhed by 
 their authority, and handed down to us. But 
 thofe who reproach us on this account, have for- 
 gotten that it was Bergman and Macquer them- 
 felves who urged us to make this reformation. 
 In a letter which the learned Profeffor of Upfal, 
 M. Bergman, wrote, a fhort time before he died, 
 to M. de Morveau, he bids him /pare no impro - 
 per names ; thofe who are learned , will akuays be 
 learned , and thofe who are ignorant will thus lean 
 fooner . , 
 
 There is an objection to the work which I am 
 going to prefent to the public, which is perhaps 
 better founded, that I have given no account of 
 the opinion of thofe who have gone before me ; 
 that I have hated only my own opinion, with- 
 out examining that of others. By this I have 
 been prevented from doing that juftice to my 
 affociates, and more efpecially to foreign che- 
 mifts, which I wifhed to render them. But I 
 befeech the reader to confider, that, if I had fil- 
 led an elementary work with a multitude of quo- 
 tations 5 if I had allowed myfelf to enter into 
 
 long 
 
PREFACE. 
 
 xxxiii 
 
 long diflertations on the hiftory of the fcience, 
 and the works of thofe who have flu died it, I 
 mufl have loft fight of the true objed: I had in 
 view, and produced a work, the reading of 
 which muft have been extremely tirefome to 
 beginners. It is not to the hiftory of the fcience, 
 or of the human mind, that we are to attend in 
 an elementary treatife : Our only aim ought to 
 be eafe and perfpicuky, and with the utmoft care 
 to keep every thing out of view which might draw 
 afide the attention of theftudent; it is a road which 
 we fhould be continually rendering more fmooth, 
 and from which we fhould endeavour to remove 
 every obftacle which can occafion delay. The 
 fciences, from their own nature, prefent a fuffi- 
 cient number of difficulties, though we add not 
 thofe which are foreign to them. But, befides 
 this, chemifts will eafily perceive, that, in the 
 firft part of my work, I make very little ufe of 
 any experiments but thofe which were made by 
 my fell : if at any time I have adopted, without 
 acknowledgment, the experiments or the opi- 
 nions of M. Berthollet, M. Fourcroy, M. deia 
 Place, M. Monge, Ga, in general, of any of thofe 
 whofe principles are the fame with my own, it 
 is owing to this circumftance, that frequent in- 
 tercourfe, and the habit of communicating our 
 e ideas. 
 
*xxiv PREFACE, 
 
 ideas, our observations, and our way of think- 
 ing to each other, has eftablifhed between us a 
 fort of community of opinions, in which it is 
 often difficult for every one to know his own. 
 
 The remarks I have made on the order which 
 1 thought myfelf obliged to follow in the ar- 
 rangement of proofs and ideas, are to be ap- 
 plied only to the firft part of this work. It is 
 the only one which contains the general fum of 
 the do&rine I have adopted, and to which I 
 wiffied to give a form completely elementary. 
 
 The Second part is compofed chiefly of tables 
 of the nomenclature qf the neutral Salts. To 
 thefe I have only added general explanations, the 
 object of which was to point out the moll Simple 
 proceffes for obtaining the ditferent kinds of 
 known acids. This part contains nothing which 
 I can call my own, and prefents only a very 
 ffiort abridgment of .the refults of thefe procef- 
 fes, extracted from the works of different au- 
 thors. 
 
 In the third part, I have given a defcription, 
 in detail, of all the operations conne&ed with 
 modern chemiftry. I have long thought that a 
 
 work 
 
PREFACE* 
 
 XXXV 
 
 work of this kind was much wanted, and I am 
 convinced it will not be without ufe. The method 
 of performing experiments, and particularly thofe 
 of modern chemiftry, is not fo generally known 
 as it ought to be ; and had I, in the different 
 memoirs which I have prefented to the Academy, 
 been more particular in the detail of the mani- 
 pulations of my experiments, it is probable l 
 fhouid have made myfelf better underftood, and 
 the fcience might have made a more rapid pro- 
 grefs. The order of the different matters con- 
 tained in this third part appeared to me to be 
 almoft arbitrary ; and the only one I have ob- 
 ferved was to clafs together, in each of the 
 chapters of which it is compofed, thofe opera* 
 tions which are moft connected with one an- 
 other. I need hardly mention that this part 
 could not be borrowed from any other work, 
 and that, in the principal articles it contains, I 
 could not derive affiftance from any thing but 
 the experiments which 1 have made myfelf. 
 
 I fhall conclude this preface by transcribing* 
 literally, fome obfervations of the Abbe de Con- 
 dillac, which 1 think defcribe, with a good deal 
 of truth, the ilate of chemiftry at a period not 
 far diflant from our own. Thefe obfervations 
 
 Were 
 
xxxvi PREFACE* 
 
 were made on a different fubjeft; but they wiil 
 not, on this account, have lefs force, if the ap- 
 plication of them be thought juft. 
 
 c Inftead of applying obfervation to the things 
 c we wifhed to know, we have choien rather to 
 6 imagine them. Advancing from one ill found- 
 
 * ed fuppofition to another, we have at laft be- 
 c wildered ourfelves amidft a multitude of errors. 
 c Thefe errors becoming prejudices, are, of 
 
 * courfe, adopted as principles, and we thus be- 
 c wilder ourfelves more and more. The method, 
 
 4 too, by which we condudl our reafonings is 
 
 * as abfurd ; we abufe words which we do not 
 
 * underhand, and call this the art of reafoning. 
 c When matters have been brought this length, 
 c when errors have been thus accumulated, there 
 c is but one remedy by which order can be 
 c reftored to the faculty of thinking ; this is, 
 c to forget all that we have learned, to trace 
 4 back our ideas to their fource, to follow the 
 c train in which they rife, and, as my Lord Ba- 
 6 con fays, to frame the human underftanding 
 c anew. 
 
 c This remedy becomes the more difficult in 
 c proportion as we think ourfelves more learn- 
 
 6 ed. 
 
preface. 
 
 xxxvia 
 
 4 ed. Might it not be thought that works which 
 4 treated of the fciences with the utmoft perfpi- 
 * cuity, with great precifion and order, mud be 
 4 underftood by every body ? The fad is, thofe 
 4 who have never ftudied any thing will under- 
 4 ftand them better than thofe who have ftudied 
 ‘a great deal, and efpecially than thofe who 
 4 have written a great deal. 
 
 At the end of the fifth chapter, the Abbe de 
 Condillac adds : 4 But, after ail, the fciences 
 4 have made progrefs, becaufe philofophers have 
 4 applied themfelves with more attention to ob- 
 4 ferve, and have communicated to their lan- 
 4 guage that precifion and accuracy which they 
 4 have employed in their obfervations : In cor- 
 4 reding their language they reafon better.’ 
 
 CON- 
 

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CONTENTS 
 
 PART FIRST. 
 
 Of the Formation and Decompofition of 
 Aeriform Fluids,— -of the Combuftion 
 of Simple Bodies, and the Formation 
 of Acids, .... Page I 
 
 CHAP. I. — Of the Combinations of Caloric, and 
 the Formation of Elaftic Aeriform Fluids or 
 Gaffes, ibid. 
 
 CHAP. II — General Views relative to the Forma- 
 tion and Compofition of our Atmofphere, 2$ 
 
 CHAP. III.— Analyfis of Atmofpheric Air, and its 
 Divifion into two Elaftic Fluids ; one fit for 
 Refpiration, the other incapable of being re- 
 fpired, 32 
 
 CHAP. IV — Nomenclature of the feveral cpnfti- 
 tuent Parts of Atmofpheric Air, 4$ 
 
 CHAP. V. — Of the Decompofition of Oxygen 
 Gas by Sulphur, Phofphorus, and Charcoal, and 
 of the Formation of Acids in general* 54 
 
 CHAPc 
 
*1 
 
 CONTENTS. 
 
 CHAP. VI. — Of the Nomenclature of Acids in ge- 
 neral, and particularly of thofe drawn from 
 Nitre and Sea Salt, Page 66 
 
 CHAP. VII. — Of the Decompofttion of Oxygen 
 Gas by means of Metals, and the Formation of 
 Metallic Oxyds, 78 
 
 CHAP. VIII.— Of the Radical Principle of Wa- 
 ter, and of its Decompofttion by Charcoal and 
 Iron, 83 
 
 CHAP. IX. — Of the Quantities of Caloric difen- 
 gaged from different Species of Combuftion, 97 
 Combuftion of Phofphorus, 100 
 
 SECT I. — Combuftion of Charcoal, ioi 
 
 SECT. II, — Combuftion of Hydrogen Gas, 102 
 
 SECT. 1H- — Formation of Nitric Acid, 102 
 
 SECT. IV. — Combuftion of Wax, 105 
 
 SECT. V. — Combuftion of Olive Oil, 106 
 
 CHAP. X — Of the Combuftion of Combuftible 
 Subftances with each other, 109 
 
 CHAP XI. — Obfervations upon Oxyds and Aci'ds 
 with feveral Bafes, and upon the Compofttion 
 of Animal and Vegetable Subftances, jj * 
 
 CHAP. XII. — Of the Decompofttion of Vegetable 
 and Animal Subftances by the Adtion of Fire, 12^ 
 CHAP. XIII. — Of the Decompofttion of Vegetable 
 Oxyds by the Vinous Fermentation, 129 
 
 CHAP. XIV.— Of the Putrefactive Fermentation, 
 
 14s 
 
 CHAP. XV. — Of the Acetous Fermentation, 146 
 
 CHAP. XVI. — Of the Formation of 'Neutral Salts, 
 and of their Bafes, 149 
 
 SECT. 
 
xli 
 
 CONTENTS. 
 
 SECT. I.— Of Potafh, 
 
 Page 15 1 
 
 SECT. II.- Of Soda, 
 
 *55 
 
 SECT. III. — Of Ammoniac, 
 
 156 
 
 SECT. IV. — Of Lime, Magnefia, Barytes, and Ar- 
 
 giU, 
 
 *57 
 
 SECT. V —Of Metallic Bodies, 
 
 *59 
 
 CHAT. XVII. — Continuation of 
 
 $he Obferva- 
 
 tions upon Salifiable Bafes, and 
 
 the Formation 
 
 of Neutral Salts, 
 
 161 
 
 PART II, 
 
 Q£ the Combinations of Acids with Sa- 
 lifiable Bafes, and of the Formation 
 of Neutral Salts a 175 
 
 INTRODUCTION, ibid, 
 
 TABLE of Simple Subftances, 175 
 
 SECT. I. — Obfervations upon limple Subfiances, 1 ~j6 
 
 TABLE of Compound Qxydable and Acidifiable 
 Bafes, 1 79 
 
 SECT. II. — Obfervations upon Compound Radi- 
 cals, 1 80 
 
 SECT. III. — Obfervations upon the Combinations 
 of Light and Caloric with different Subftances, i8z 
 TABLE of the Combinations of Oxygen with the 
 Simple Subfiances, to face 18 ; 
 
 / SECT. 
 
CONTENTS. 
 
 xlii 
 
 SECT. IV. — Obfervations upon thefe Combina- 
 tions, Page 183 
 
 TABLE of the Combinations of Oxygen with Com- 
 pound Radicals, 190 
 
 SECT. V. — Obfervations upon thefe Combina- 
 tions, 1 91 
 
 TABLE of the Combinations of Azote with the 
 Simple Subftances, 194 
 
 SECT. VI. — Obfervations upon thefe Combina- 
 tions of Azote, 195 
 
 TABLE of the Combinations of Hydrogen with 
 Simple Subftances, 198 
 
 SECT. VII — Obfervations upon Hydrogen, and its 
 Combinations, 199 
 
 TABLE of the Binary Combinations of Sulphur 
 with the Simple Subftances, 202 
 
 SECT. VIII. — Obfervations upon Sulphur, and its 
 Combinations, 203 
 
 TABLE of the Combinations of Phofphorus with 
 Simple Subftances, 204 
 
 SECT. IX. — Obfervations upon Phofphorus and its 
 Combinations, 205 
 
 TABLE of the Binary Combinations of Charcoal, 207 
 SECT. X. — Obfervations upon Charcoal, and its 
 Combinations, 208 
 
 SECT. XL — Obfervations upon the Muriatic, Flu- 
 oric, and Boracic Radicals, and their Combina- 
 tions, 2C9 
 
 SECT. XII. — Obfervations upon the Combinations 
 of Metals with each other, 219 
 
 TABLE 
 
CONTENTS. 
 
 xliii 
 
 TABLE of the Combinations of Azote, in the State 
 of Nitrous Acid, with the Salifiable Bafes, 
 
 Page 212 
 
 TABLE of the Combinations of Azote, in the State 
 of Nitric Acid, with the Salifiable Bafes 213 
 
 SECT. XIII. — Obfervations upon Nitrous and Ni- 
 tric Acids, and their Combinations with Salifi- 
 able Bafes, 214 
 
 TABLE of the Combinations of Sulphuric Acid 
 with the Salifiable Bafes, 2 1 8 
 
 SECT. XIV.— Obfervations upon Sulphuric Acid, 
 and its Combinations, 219 
 
 TABLE of the Combinations of Sulphurous Acid, 222 
 SECT. XV. — Obfervations upon Sulphurous Acid, 
 and its Combinations with Salifiable Bales, 223 
 
 TABLE of the Combinations of Phofphorous and 
 Phofphoric Acids, 225 
 
 SECT. XVI. — Obfervations upon Phofphorous and 
 Phofphoric Acids, and their Combinations 
 with Salifiable Bafes, 226 
 
 TABLE of the Combinations of Carbonic Acid, 228 
 SECT. XVII. — Obfervations upon Carbonic Acid, 
 aud its Combinations with Salifiable Bafes, 229 
 
 TABLE of the Combinations of Muriatic Acid, 231 
 
 TABLE of the Combinations of Oxygenated Muri- 
 atic Acid, 232 
 
 SECT. XVIII. — Obfervations upon Muriatic and 
 Oxygenated Muriatic Acid, and their Combina- 
 tions with Salifiable Bafes, 233 
 
 TABLE 
 
xliv CONTENTS. 
 
 TABLE of the Combinations of Nitro-Muriatic A- 
 cid, Page 23 6 
 
 SECT. XtX. — Obfervations upon Nitro-muriatie 
 Acid, and its Combinations with Salifiable 
 Bales, 237 
 
 TABLE of the Combinations of Fluoric Acid, 23# 
 ECT. XX — Obfervations upon Fluoric Acid, and 
 its Combinations with Salifiable Bafes, 240 
 
 TABLE of the Combinations of Boracic Acid, 242 
 SECT. XXI — Obfervations upon Boracic Acid, 
 and its Combinations with Salifiable Bafes, 243 
 TABLE of the Combinations of Arfeniac Acid, 246 
 SECT. XXII. — Obfervations upon Arfeniac Acid, 
 and it's Combinations with Salifiable Bafes, 247 
 SECT. XXIII. — Obfervations upon Molibdic Acid, 
 and its Combinations with Salifiable Bafes, 249 
 
 SECT. XXIV. — Obfervations upon Tungftic Acid, 
 and its Combinations with Salifiable Bafes, and 
 a Table of thefe in the order of their Affinity, 251 
 TABLE of the Combinations of Tartarous Acid, 253 
 SECT. XXV. — Obfervations upon Tartarous Acid, 
 and its Combinations with Salifiable Bafes, 254 
 SECT. XXVI. — Obfervations upon Mallic Acid, 
 and its Combinations with Salifiable Bafes, 256 
 TABLE of the Combinations of Citric Acid, 25 S 
 
 SECT. XXVII.— Obfervations upon Citric Acid* 
 and its Combinations with Salifiable Bafes, 259 
 
 TABLE of the Combinations of Pyro-lignous A- 
 cid, 260 
 
 SECT. 
 
ft O S T E » T Si 
 
 
 SECT. XXVIII. —Obfervations upon Pyro-lignous 
 Acid, and its Combinations with Salifiable Sa- 
 fes, Page 2 6t 
 
 SEC f . XXIX. — Obfervations upon Pyro-tartarous 
 Acid, and its Combinations with Salifiable 
 Bafes, ibid* 
 
 TABLE of the Combinations of Pyro-mucous A- 
 cid, 263 
 
 SECT. XXX. — Obfervations upon Pyro-mucous 
 Acid, and its Combinations with Salifiable Ba- 
 fes, 264 
 
 TABLE of the Combinations of Oxalic Acid, 263 
 
 SECT. XXXI. — Obfervations upon Oxalic Acid, 
 and its Combinations with Salifiable Bafes y 2 66 
 
 TABLE of the Combinations of Acetous Acid, to 
 
 face 267 
 
 SECT. XXXII. — Obfervations upon Acetous Acid, 
 and its Combinations with the Salifiable Bafes, 267 
 TABLE of the Combinations of Acetic Add, 27 1 
 
 SECT. XXXIII. — Obfervations upon Acetic Acid, 
 and its Combinations with Salifiable Bafes, 272 
 
 TABLE of the Combinations of Succinic Acid, 273 
 
 SECT. XXXIV — Obfervations upon Succinic A- 
 cid, and its Combinations with Salifiable Ba- 
 fe s , 274 
 
 SECT. XXXV. — Obfervations upon Benzoic Acid, 
 and its Combinations with Salifiable Bafes, 27 £ 
 
 SECT. XXXVI. — Obfervations upon Camphoric 
 Acid, and its Combinations with Salifiable 
 Bafes, 276 
 
 SECT, 
 
/ 
 
 CONTENT 
 
 SECT. XXXVII. — Obfervations upon Gallic Acid, 
 and its Combinations with Salifiable Bafes, Page 277 
 SECT. XXXVIII. — Obfervations upon La&ic Acid, 
 and its Combinations with Salifiable Bafes, 27 8 
 
 TABLE of the Combinations of Saccho«la&ic A- 
 cid, 280 
 
 SECT. XXXIX. — Obfervations upon Saccho-la&ic 
 Acid, and its Combination with Salifiable Bafes, 281 
 TABLE of the Combinations of Formic Acid, 282 
 SECT. XL. — Obfervations upon Formic Acid, and 
 its Combinations with the Salifiable Bafes, 283 
 
 SECT. XLI. — Obfervations upon the Bombic Acid, 
 and its Combinations with the Salifiable Bafes, 284 
 TABLE of the Combinations of the Sebacic Acid, 285 
 SECT. XLII.-— -Obfervations upon the Sebacic A- 
 cid, and its Combinations with the Salifiable 
 Bafes, 286 
 
 SECT. XLIII. — Obfervations upon the Lithic Acid, 
 and its Combinations with the Salifiable Bafes, 287 
 TABLE of the Combinations of the Pruflic Acid, 288 
 SECT. XLIV. — Obfervations upon the Prufiic A- 
 cid, and its Combinations with the Salifiable 
 Bafes, 289 
 
 PART in. 
 
 Defcription of the Inftruments and Ope- 
 rations of Chemiftry, 291 
 
 INTRO- 
 
CONTENTS. 
 
 Xlv* 
 
 INTRODUCTION, Page 2 9 i 
 
 CHAP. I. — Of the Inftruments neceffary for deter- 
 mining the Abfolute and Specific Gravities of 
 Solid and Liquid Bodies, 295 
 
 CHAP. II. — Of Gazometry, or the Meafurement 
 of the Weight and Volume of Aeriform Sub- 
 ftances, 304 
 
 SECT. I. — Of the Pneumato-chemical Apparatus, ibid. 
 SECT. II. — Of the Gazometer, 308 
 
 SECT. III. — Some other methods for Meafuring 
 the Volume of Gaffes, 319 
 
 SECT. IV Of the method of Separating the dif- 
 ferent Gaffes from each other, 323 
 
 SECT. V. — Of the neceffary Corrections of the Vo- 
 lume of Gaffes, according to the Preffure of 
 the Atmofphere, 328 
 
 SECT. VI.— Of the Correction relative to the De- 
 grees of the Thermometer, 33^ 
 
 SECT. VII. — Example for Calculating the Correc- 
 tions relative to the Variations of Preffure and 
 Temperature, 337 
 
 SECT. VIII. — Method of determining the Weight 
 of the different Gaffes, 340 
 
 CHAP. III.- — Oefcription of the Calorimeter, or 
 Apparatus for meafuring Caloric, 343 
 
 CHAP. IV. — Of the Mechanical Operations for 
 Divifion of Bodies, 3 57 
 
 SECT. I. — Of Trituration, Levigation, and Pulve- 
 rization, ibid. 
 
 SECT. 
 
CONTENTS- 
 
 civ’ll i 
 
 SECT. II. — Of Sifting and Wafhing Powdered 
 Subftances, Page 3 6 1 
 
 SECT ill — Of Filtration, 363 
 
 SECT. IV. — Of Decantation, 365 
 
 CH AP. V.— Of Chemical means for Separating the 
 Particles of Bodies from each other without 
 Decompofiiion, and for Uniting them again, 367 
 
 SECT I Of the Solution of baits, 368 
 
 SECT. 11. — Ot Lixiviation, 373 
 
 SECT III. — Of Evaporation, 37$ 
 
 SECT. IV. — Of Criftailization, 379 
 
 SE> T. V. — Of Simple Diftillation, 384 
 
 SEC E. * r I. — Of Sublimation, 388 
 
 CHAP. VI. — Of Pneumato-chemical Diftillations, 
 Metallic DifTolutions, and 1'ome other operations 
 which require very complicated inftruments, 390 
 SECT I. — Of Compound and Pneumato-chemical 
 Diftillations, ibid. 
 
 SEC T. II.— —Of Metallic DifTolutions, 398 
 
 SECT. III. — Apparatus neceftarv in Experiments 
 upon Vinous and Putrefactive Fermentations, 401 
 SEC f. IV. — Apparatus for the Decompolition of 
 Water, 404 
 
 CHAP. VII. — Of the Compofition and Ufe of 
 Lutes, 407 
 
 CHAP VIII. — Of Operations upon Combuftion 
 and Deflagration, 414 
 
 SEC 1 . I. —Of Combuftion in general, ibid. 
 
 SECT. II. — Of the Combuftion of Phofphorus, 418 
 SECT. III.— Of the Combuftion of Charcoal, 422 
 
 SECT- 
 
CONTENTS. 
 
 xli* 
 
 SECT. IV. — Of the Combuftion of Oils, Page 426 
 SECT. V. — Of the Combuftion of Alkohol, 433 
 
 SECT. VI. — Of the Combuftion of Ether, 435 
 
 SECT. VII. — Of the Combuftion of Hydrogen 
 Gas, and the Formation of Water, 437 
 
 SECT. VIII. — Of the Oxydation of Metals, 441 
 CHAP. IX. — Of Deflagration, 452 
 
 CHAP. X. — Of the Inftruments neceflaryfor Ope- 
 rating upon Bodies in very high Temperatures, 460 
 SECT. I— Of Fuflon, ibid. 
 
 SECT. II. — Of Furnaces, 462 
 
 SECT. III.-: — Of increafing the A<ftion of Fire, by 
 ufing Oxygen Gas infteadof Atmofpheric Air, 474 
 
 APPENDIX, 
 
 No. I. — Table for Converting Lines, or Twelfth 
 Parts of an Inch, and Fra&ions of Lines, into 
 Decimal Fra&ions of the Inch, 481 
 
 No. II. — Table for Converting the Obferved 
 Heighth of Water in the Jars of the Pneumato- 
 Chemical Apparatus, exprefled in Inches and 
 Decimals, into Correfponding Heighths of Mer- 
 cury, 482 
 
 No. HI. — Table for Converting the Ounce 
 Meafures ufed by Dr Prieftley into French and 
 Englilh Cubical Inches, 483 
 
 No. IV — Table for Reducing the Degrees of 
 Reaumeur’s Thermometer into its correfponding 
 Degrees of Fahrenheit’s Scale, 484 
 
 J? NO; 
 
I 
 
 CONTENTS. 
 
 No. V. — Additional. — Rules for Converting 
 French Weights and Meafures into correfpon- 
 dent Englifh Denominations, Page 48$ 
 
 No. VI. — Table of the Weights of the different 
 Gaffes, at 28 French inches, or 29.84 Englifh 
 inches barometrical preffure, and at io° (54. 5 0 ) 
 of temperature, expreffed in Englifh meafurc 
 and Englifh Troy weight, 490 
 
 No. VII. — Tables of the Specific Gravities of 
 different bodies, 491 
 
 No. VIII. — Additional.— Rules for Calcula- 
 ting the Abfolute Gravity in Englifh Troy 
 Weight of a Cubic Foot and Inch, Englifh 
 Meafure, of any Subfiance whofe Specific Gra- 
 vity is known, 505 
 
 No. IX. — Tables for Converting Ounces, Drams, 
 and Grains, Troy, into Decimals of the Troy 
 Pound of 12 Ounces, and for Converting Deci- 
 mals of the Pound Troy into Ounces, &c. 508 
 
 No. X. — Table of the Englifh Cubical Inches and 
 Decimals correfponding to a determinate Troy 
 Weight of Diflilled Water at the Temperature 
 ©f 5 5°> calculated from Everard’s experiment, 5 1 1 
 
 E L E- 
 
ELEMENTS 
 
 O F 
 
 CHEMISTRY- 
 
 PART I. 
 
 Of the Formation and Decompofi- 
 tion of Aeriform Fluids— of the 
 Combuftion of Simple Bodies — 
 and the Formation of Acids. 
 
 CHAP. I. 
 
 Of the Combinations of Caloric , and the Formation 
 of Elaftic Aeriform Fluids . 
 
 T HAT every body, whether folid or fluid, 
 is augmented in all its dimenfions by any 
 increafe of its fenfible heat, was long ago fully 
 eftablifhed as a phyfical axiom, or univerfal pro- 
 pofition, by the celebrated Boerhaave, Such 
 fads as have been adduced for controverting the 
 A generality 
 
ELEMENTS 
 
 £ 
 
 generality of this principle offer only fallacious 
 refults, or, at lead, fuch as are fo complicated 
 with foreign circumflances as to miflead the 
 judgment : But, when we feparately confider the 
 efrefts, fo as to deduce each from the caufe to 
 which they feparately belong, it is eafy to per- 
 ceive that the feparation of particles by heat is 
 a conflant and general law of nature. 
 
 When we have heated a folid body to a cer- 
 tain degree, and have thereby caufed its particles 
 to feparaie from each other, if we allow the 
 body to cool, its particles again approach each 
 other in the fame proportion in which they were 
 separated by the increafed temperature; the bo- 
 dy returns through the fame degrees of expan- 
 fion which it before extended through ; and, if 
 it be brought back to the fame temperature from 
 which we fet cut at the commencement of the 
 experiment, it recovers exadlly the fame dimen- 
 sions which it formerly occupied. But, as we 
 are flill very far from being able to arrive at 
 the degree of abfolute cold, or deprivation of 
 all heat, being unacquainted with any degree 
 of coldnefs which we cannot fuppofe capable 
 of flill farther augmentation, it follows, that 
 we are flill incapable of caufing the ultimate 
 particles of bodies to approach each other as 
 near as is poflible ; and, confequently, that 
 the particles of all bodies do not touch each 
 other in any flate hitherto known, which, tho* 
 
 a 
 
O F C H E J \1 I S T R Y, * 
 
 a very fingular conclufion, is yet impoffible to 
 be denied. 
 
 It is fuppofed, that, fi'nce the particles of bo° 
 dies are thus continually impelled by heat to 
 feparate from each other, they would have no 
 connection between themfelves ; and, of confe- 
 quence, that there could be no folidity in na- 
 ture, unlefs they were held together by fome 
 other power which tends to unite them, and, 
 fo to fpeak, to chain them together ; which 
 power, whatever be its caufe, of manner of ope- 
 ration, we name Attraction. 
 
 Thus the particles of all bodies may be con- 
 fidered as fubjeCted to the aCtion of two op- 
 pofite powers, the one repuifive, the other at« 
 tractive, between which they remain in equili- 
 brio. So long as the attractive force remains 
 ftronger, the body muft continue in a (late of 
 folidity ; but if, on the contrary, heat has fo 
 far removed thefe particles from each other, as 
 to place them beyond the fphere of attraction, 
 they lofe the adhefion they before had with 
 each other, and the body ceafes to be folid. 
 
 Water gives us a regular and conftant ex- 
 ample of thefe faCts ; whilft below Zero * of 
 the French thermometer, or 3 2° of Fahrenheit/ 
 
 it 
 
 * Whenever the degree of heat occurs in this work, 
 h is hated by the author according to Reaumur’s fcale. 
 The degrees within brackets are the correfpondent de- 
 grees of Fahrenheit’s fcale, added by the tranflator. 
 
4 
 
 ELEMENTS 
 
 it remains folid, and is called ice. Above that 
 degree of temperature, its particles being no 
 longer held together by reciprocal attraction, it 
 becomes liquid ; and, when we raife its tem- 
 perature above 8 o°, (21 2 0 ) its particles, giving 
 way to the repulfion caufed by the heat, affume 
 the ftate of vapour or gas, and the water is 
 changed into an aeriform fluid. 
 
 The fame may be affirmed of all bodies in 
 nature : They are either folid or liquid, or in 
 the ftate of elaftic aeriform vapour, according 
 to the proportion which takes place between 
 the attractive force inherent in their particles, 
 and the repulftve power of the heat aCting upon 
 thefe ; or, what amounts to the fame thing, in 
 proportion to the degree of heat to which they 
 are expofed. 
 
 It is difficult to comprehend thefe pheno- 
 mena, without admitting them as the effeCts of 
 a real and material fubftance, or very fubtile 
 fluid,, which, infinuating itfelf between the par- 
 ticles of bodies, feparates them from each o- 
 ther ; and, even allowing the exiftence of this 
 fluid to be hypothetical, we fhall fee in the fe- 
 quel, that it explains the phenomena of nature 
 in a very fatisfaCtory manner. 
 
 This fubftance, whatever it is, being the caufe 
 of heat, or, in other words, the fenfation which 
 we call warmth being caufed by the accumula- 
 tion of this fubftance, we cannot, in ftriCt lan- 
 guage 
 
OF CHEMISTRY. $ 
 
 guage, diftinguifh it by the term heat ; becaufe 
 the fame name would then very improperly ex- 
 prefs both caufe and effed. For this reafon, in 
 the memoir which I publilhed in 1777 *, I gave 
 it the names of igneous fluid and matter of heat : 
 And, fince that time, in the work f publilhed 
 by Mr de Morveau, Mr Berthollet, Mr de Four- 
 croy, and myfelf, upon the reformation of che- 
 mical nomenclature, we thought it necelfary to 
 banilh all periphraltic expreliions, which both 
 lengthen phyfical language, and render it 
 more tedious and lefs diftind, and which even 
 frequently does not convey fufficiently juft ideas 
 of the fubjed intended. Wherefore, we have 
 diftinguilhed the caufe of heat, or that exqui- 
 litely elaftic fluid which produces it, by the 
 term of caloric . Befides, that this expreflion 
 fulfils our objed in the fyltem which we have 
 adopted, it polfelfes this farther advantage, that 
 it accords with every fpecies of opinion, fince, 
 ftridly fpeaking, we are not obliged to fuppofe 
 this to be a real fubftance ; it being fufflcient, 
 as will more clearly appear in the fequel of this 
 work, that it be confidered as the repullive 
 caufe, whatever that may be, which feparates 
 the particles of matter from each other 5 fo that 
 
 we 
 
 * Collections of the French Academy of Sciences 
 for that year, p. 420. 
 
 f Chemical Nomenclature* 
 
$ ELEMENTS 
 
 we are ftill at liberty to inveftigate its effe&s lit 
 an abftraft and mathematical manner* 
 
 In the prefent ftate of our knowledge, we are 
 unable to determine whether light be a modifi- 
 cation of caloric, or if caloric be, on the con- 
 trary, a modification of light. This, however, 
 is indifputable, that, in a fyftem where only de- 
 cided faffs are admiflible, and where we avoid, 
 as far as poffible, to fuppofe any thing to be 
 that is not really known to exift, we ought pro- 
 vifionally to diftinguifh, by diftind terms, fuch 
 things as are known to produce different ef- 
 fects. We therefore diftinguifh light from ca- 
 loric ; though we do not therefore deny that 
 thefe have certain qualities in common, and 
 that, in certain circumftances, they combine 
 with other bodies almoft in the fame manner, 
 and produce, in part, the fame effects. 
 
 What I have already faid may fuffice to 
 determine the idea affixed to the word calo* 
 ric ; but there remains a more difficult attempt, 
 which is, to give a juft conception of the man- 
 ner in which caloric afls upon other bodies. 
 Since this fubtile matter penetrates through the 
 pores of all known fubftances ; fince there are 
 no veffels through which it cannot efcape, and, 
 confequently, as there are none which are capa- 
 ble of retaining it, we can only come at the 
 knowledge of its properties by effefts which are 
 fleeting, and difficultly afcertainable. It is in 
 
 thefe 
 
OF CHEMISTRY, f 
 
 thefe things which we neither fee nor feel, that 
 it is efpecially neceflary to guard againft the 
 extravagancy of our imagination, which for- 
 ever inclines to ftep beyond the bounds of 
 truth, and is very difficultly reftrained within 
 the narrow line of fads. 
 
 We have already feen, that the fame body 
 becomes folid, or fluid, or aeriform, according 
 to the quantity of caloric by which it is pene- 
 trated ; or, to fpeak more ftridly, according as 
 the repulfive force exerted by the caloric is 
 equal to, ftronger, or weaker, than the attrac- 
 tion of the particles of the body it ads upon. 
 
 Rut, if thefe two powers only exifted, bodies 
 would become liquid at an indivifible degree of 
 the thermometer, and would almoft inftantane- 
 oufly pafs from the folid ftate of aggregation to 
 that of aeriform elafticity. Thus water, for in- 
 ftance, at the very moment when it ceafes to be 
 ice, would begin to boil, and would be trans- 
 formed into an aeriform fluid, having its parti- 
 cles fcattered indefinitely through the furround- 
 ing fpace. That this does not happen, muff de- 
 pend upon the adion of fome third power. The 
 preflure of the atmofphere prevents this fepara- 
 tion, and caufes the water to remain in the li- 
 quid date till it be raifed to 8 o° of tempe- 
 rature (212 0 ) above zero of the French ther- 
 mometer, the quantity of caloric which it re- 
 ceives in the loweft temperature being infuffi- 
 
 eient 
 
ELEMENTS 
 
 § 
 
 dent to overcome the preffure of the atmo- 
 fphere. 
 
 Whence it appears that, without this atmo- 
 fpheric preffure, we fhould not have any perma- 
 nent liquid, and fhould only be able to fee bo- 
 dies in that flate of exiftence in the very inftant 
 of melting, as the fmallefl additional caloric 
 would inftantly feparate their particles, and difli- 
 pate them through the furrounding medium. 
 Befides, without this atmofpheric preffure, we 
 fhould not even have any aeriform fluids, ftridly 
 fpeaking, becaufe the moment the force of at- 
 tra&ion is overcome by the repuifive power of 
 the caloric, the particles would feparate them- 
 felves indefinitely, having nothing to give limits 
 to their expanfion, unlefs their own gravity 
 might colled them together, fo as to form an 
 atmofphere. 
 
 Simple refle&ion upon the mofl common ex- 
 periments is fufficient to evince the truth of 
 thefe pofitions. They are more particularly 
 proved by the following experiment, which I 
 pubiifhed in the Memoirs of the French Aca- 
 demy for 1777, P- 426. 
 
 Having filled with fulphuric ether * a fmall nar- 
 row glafs veffel, A, (Plate VII. Fig. 17.), {land- 
 ing 
 
 * As I fnall afterwards give a definition, and ex- 
 plain the properties of the liquor called ether, I fhali 
 only premife here, that it is a very volatile inflam- 
 mable 
 
OF CHEMlSTRt 
 
 ing upon its ftalk P, the veffel, which is from 
 twelve to fifteen lines diameter, is to be cover- 
 ed by a wet bladder, tied round its neck with 
 feveral turns of ilrong thread ; for greater fe- 
 curity, ^x a fecond bladder over the firft. The 
 veffel fhould be filled in fuch a manner with 
 the ether, as not to leave the fmalleft portion 
 of air between the liquor and the bladder* 
 It is now to be placed under the recipient 
 BCD of an air-pump, of which the upper 
 part B ought to be fitted with a leathern lid* 
 through which paffes a wire EF, having its 
 point F very fharp ; and in the lame receiver 
 there ought to be placed the barometer GH* 
 The whole being thus difpofed, let the recipient 
 be exhaufted, and then, by pufhing down the 
 wire EF, we make a hole in the bladder. Im- 
 mediately the ether begins to boil with great 
 violence, and is changed into an elaftic aeri- 
 form fluid, which fills the receiver. If the 
 quantity of ether be fufficient to leave a few 
 drops in the phial after the evaporation is fi ruffl- 
 ed, the elaftic fluid produced will fuftain the 
 mercury in the barometer attached to the air- 
 pump, at eight or ten inches in winter, and from 
 
 B twenty 
 
 mable liquor, having a confiderably fmajler fpecific 
 
 
10 
 
 ELEMENTS 
 
 twenty to twenty-five in fummer *. To render 
 this experiment more complete, we may intro- 
 duce a fmall thermometer into the phial A, con- 
 taining the ether, which will defcend confider- 
 ably during the evaporation. 
 
 The only effedfc produced in this experiment 
 is, the taking away the weight of the atmofphere, 
 which, in its ordinary date, preffes on the fur- 
 face of the ether ; and the effe&s refulting from 
 this removal evidently prove, that, in the ordi- 
 nary temperature of the earth, ether would al- 
 ways exift in an aeriform ftate, but for the pref- 
 i’ure of the atmofphere, and that the pafling of 
 the ether from the liquid to the aeriform ftate 
 is accompanied by a confiderable leffening of 
 heat ; beeaufe, during the evaporation, a part of 
 the caloric, which was before in a free ftate, or 
 at leaft in equilibrio in the furrounding bo- 
 dies, combines with the ether, and caufes it to 
 affume the aeriform ftate. 
 
 The fame experiment fucceeds with all eva- 
 porable fluids, fuch as alkohol, water, and even 
 mercury \ with this difference, that the at- 
 mofphere formed in the receiver by alkohol only 
 
 fupports 
 
 * It would have been more fatisfa&ory if the Author 
 had fpecified the degrees of the thermometer at which, 
 thefe heights of the mercury in the barometer are pro- 
 duced. 
 
OF CHEMISTRY. 
 
 1 1 
 
 fupports the attached barometer about one inch 
 in winter, and about four or five inches in fum- 
 mer ; that formed by water, in the fame fixa- 
 tion, raifes the mercury only a few lines, and 
 that by quickfilver but a few fractions of a line. 
 There is therefore lefs fluid evaporated from al- 
 kohol than from ether, lefs from water than 
 from alkohol, and fliii lefs from mercury than 
 from either ; confequently there is lefs caloric 
 employed, and lefs cold produced, which qua- 
 drates exactly with the refults of thefe experi- 
 ments. 
 
 Another fpecies of experiment proves very e- 
 vidently that the aeriform ftate is a modifica- 
 tion of bodies dependent on the degree of tem- 
 perature, and on the preffure which thefe bodies 
 undergo. In a Memoir read by Mr de la Place 
 and me to the Academy in 1^77, which has not 
 been printed, we have fhown, that, when ether 
 is fubjefted to a preffure equal to twenty. eight 
 inches of the barometer, or about the medium 
 preffure of the atmofphere, it boils at the tem- 
 perature of about 32 0 (104), or 33 0 (1 06.25°), 
 of the thermometer. Mr de Luc, who has made 
 fimilar experiments with fpirit of wine, finds 
 it boils at 67° (182.75°). And all the world 
 knows that water boils at 8 o d (212°). Now, 
 boiling being only the evaporation of a liquid, 
 or the moment of its palling from the fluid to 
 the aeriform ftate, it is evident that, if we keep 
 
 ether 
 
ELEMENTS 
 
 *2 
 
 ether continually at the temperature of 33* 
 (106.25°), under the common preffure of 
 the atmofphere, we (hail have it always in an e- 
 laftic aeriform ftate; and that the fame thing will 
 happen with alkohol when above 67° (182.75°), 
 and with water when above 8o° (212 0 ); all 
 which are perfe&ly conformable to the fol- 
 lowing experiment *. 
 
 I filled a large veffel ABCD (Plate VII. 
 Fig. 16.) with water, at 35 0 (110.75°), or 36° 
 ( 1 1 3 0 ) ; I fuppofe the veffel tranfparent, that we 
 may fee what takes place in the experiment ; 
 and we can eafiiy hold the hands in water at 
 that temperature without inconvenience. Into 
 it I plunged fome narrow necked bottles F, G, 
 which were filled with the water, after which they 
 were turned up, fo as to reft on their mouths on 
 the bottom of the veffel. Having next put fome 
 ether into a very fmall matrafs, with its neck 
 a b c, twice bent as in the Plate, I plunged this 
 matrafs into the water, fo as to have its neck 
 inferted into the mouth of one of the bottles F. 
 Immediately upon feeling the effects of the heat 
 communicated to it by the water in the veffel 
 ABCD it began to boil ; and the caloric 
 entering into combination with it, changed it 
 into elaftic aeriform fluid, with which I filled 
 feveral bottles fucceffively, F, G, &c. 
 
 This 
 
 * Vide Memoirs of the French Academy, anno 
 
 :7$o, P' 335‘— A. 
 
OF CHEMISTRY. Yj 
 
 This is not the place to enter upon the exa- 
 mination of the nature and properties of this 
 aeriform fluid, which is extremely inflammable * 
 but, confining myfelf to the objed at prefent in 
 view, without anticipating circumftances, which 
 I am not to fuppofe the reader to know, I fhall 
 only obferve, that the ether, from this experi- 
 ment, is almoft only capable of exifting in the ae- 
 riform ftate in our world ; for, if the weight of 
 our atmofphere was only equal to between 20 
 and 24 inches of the barometer, inftead of 28 
 inches, we fhould never be able to obtain ether 
 in the liquid ftate, at leaft in fummer ; and the 
 formation of ether would confequently be im» 
 poflible upon mountains of a moderate degree 
 of elevation, as it would be converted into gas 
 immediately upon being produced, unlefs we 
 employed recipients of extraordinary ftrength, 
 together with refrigeration and comprefiion. 
 And, laftly, the temperature of the blood being 
 nearly that at which ether paffes from the li- 
 quid to the aeriform ftate, it muft evaporate in 
 the primae yiae, and confequently it is very 
 probable the medical properties of this fluid 
 depend chiefly upon its mechanical effed. 
 
 Thefe experiments fucceed better with nitrous 
 ether, becaufe it evaporates in a lower tempera- 
 ture than fulphuric ether. It is more difficult to 
 obtain alkohol in the aeriform ftate ; becaufe, 
 as it requires 67° (j 82,75°) to reduce it to va- 
 pour. 
 
ELEMENTS 
 
 r u 
 
 pour, the water of the bath muft be almoft 
 boiling, and confequently it is impoflible to 
 plunge the hands into it at that temperature. 
 
 It is evident that, if water were ufed in the 
 foregoing experiment, it would be changed into 
 gas, when expofed to a temperature fuperior to 
 that at which it boils. Although thoroughly 
 convinced of this, Mr de la Place and myfelf 
 judged it neceffary to confirm it by the follow- 
 ing dirett experiment. We filled a glafs jar A, 
 (Plate VII. Fig. 5.) with mercury, and placed 
 it with its mouth downwards in a difh B, like- 
 wife filled with mercury, and having intro- 
 duced about two grofs of water into the jar, 
 which rofe to the top of the mercury at CD; 
 we then plunged the whole apparatus into an 
 iron boiler EFGH, full of boiling fea-water of 
 the temperature of 85° (123.25 0 ), placed upon 
 the furnace GHIK. Immediately upon the wa- 
 ter over the mercury attaining the temperature 
 of 8o° ( 21 2°), it began to boil ; and, inftead of 
 only filling the final! fpace ACD, it was con- 
 verted into an aeriform fluid, which filled the 
 whole jar ; the mercury even defcended below 
 the furface of that in the difh B ; and the jar 
 muft have been overturned, if it had not been 
 very thick and heavy, and fixed to the difh by 
 means of iron-wire. Immediately after with- 
 drawing the apparatus from the boiler, the va- 
 pour in the jar began to condenfe, and the 
 v ‘ mercury 
 
OF CHEMISTRY. 
 
 *1 
 
 mercury rofe to its former ftation ; but it re- 
 turned again to the aeriform ftate a few feconds 
 after replacing the apparatus in the boiler. 
 
 We have thus a certain number of fub- 
 ftances, which are convertible into elaflic aeri- 
 form fluids by degrees of temperature, not 
 much fuperior to that of our atmofphere. We 
 fhall afterwards find that there are feveral others 
 which undergo thefame change infimilar circum- 
 fiances, fuch as muriatic or marine acid, ammo- 
 niac or volatile alkali, the carbonic acid or fixed 
 air, the fulphurous acid, &c. All of thefe are 
 permanently elaftic in or about the mean temper 
 rature of the atmofphere, and under its common 
 preflure. 
 
 All thefe fafts, which could be eafily multi- 
 plied if neceflary, give me full right to aflame, 
 as a general principle, that almofi every body 
 in nature is fufceptible of three feveral ftates of 
 exiftence, folid, liquid, and aeriform, and 
 that thefe three fiates of exiftence depend upon 
 the quantity of caloric combined with the 
 body. Henceforwards I fhall exprefs thefe 
 
 elaftic aeriform fluids by the generic term 
 gas ; and in each fpecies of gas I fhall diftin- 
 guifh between the caloric, which in fome mea- 
 fure ferves the purpofe of a folvent, and the fub- 
 ftance, which in combination with the caloric, 
 forms the bafe of the gas. 
 
 To 
 
16 Elements 
 
 \ 
 
 To thefe bafes of the different gaffes, which 
 are hitherto but little known, we have been o« 
 bliged to affign names ; thefe I lhall point out 
 in Chap. IV. of this work, when I have pre- 
 vioufly given an account of the phenomena at- 
 tendant upon the heating and cooling of bodies, 
 and when I have eftablifhed precife ideas con- 
 cerning the compofition of our atmofphere. 
 
 We have already fhown, that the particles of 
 every fubftance in nature exift in a certain 
 ftate of equilibrium, between that attra&ion 
 which tends to unite and keep the particles to- 
 gether, and the effects of the caloric which 
 tends to feparate them. Hence the caloric 
 not only furrounds the particles of all bo- 
 dies on every fide, but fills up every inter- 
 val which the particles of bodies leave be- 
 tween each other. We may form an idea of 
 this, by fuppofmg a veffel filled with fmall lphe- 
 rical leaden bullets, into which a quantity of 
 fine fand is poured, which, infmuating into the 
 intervals between the bullets, will fill up every 
 void. The balls, in this comparifon, are to the 
 fand which furrounds them exactly in the fame 
 fituation as the particles of bodies are with refpeft 
 to the caloric y with this difference only, that 
 the balls are fuppofed to touch each other, 
 whereas the particles of bodies are not in con- 
 tadf, being retained at a fmall diftance from 
 each other, by the caloric. 
 
 If 
 
OF CHEMISTRY. 
 
 If, inftead of fpherlcal balls, we fubftitute folid 
 bodies of a hexahedral, oCtohedral, cr any o- 
 ther regular figure, the capacity of the inter- 
 vals between them will be leflened, and confe- 
 quently v/ill no longer contain the fame quan- 
 tity of fand. The fame thing takes place, with 
 refpeCl to natural bodies ; the intervals left be- 
 tween their particles are not of equal capacity, 
 but vary in confequence of the different figures 
 and magnitude of their particles, and of the 
 diftance at which thefe particles are maintain- 
 ed, according to the exifting proportion be- 
 tween their inherent attraction, and the repul- 
 five force exerted upon them by the caloric. 
 
 In this manner we muff underhand the fol- 
 lowing exprefiion, introduced by the Englifh 
 philofophers, who have given us the firfi pre- 
 cife ideas upon this fubjeCt ; the capacity of bodies, 
 for containing the matter of heat. As compan- 
 ions with fenfibie objects are of great uie in 
 abiding us to form diftinCt notions of abftract 
 ideas, we fhall endeavour to illui'lrate this, by 
 inftancing the phenomena which take piaec 
 between water and bodies which are wetted 
 and penetrated by it, with a few reflections. 
 
 If we immerge equal pieces of different kinds 
 of wood, fuppofe cubes of one foot each, into 
 water, the fluid gradually infmuates itfelf into 
 their pores, and the pieces of wood are aug- 
 mented both in weight and magnitude : But 
 
 C each 
 
ELEMENTS 
 
 1 8 
 
 each fpecies of wood will imbibe a different 
 quantity of water ; the lighter and more porous 
 woods will admit a larger, the compact and clofer 
 grained will admit of a leffer quantity ; for the 
 proportional quantities of water imbibed by the 
 pieces will depend upon the nature of the con- 
 flituent particles of the wood, and upon the 
 greater or leffer affinity fubfifting between them 
 and water. Very refinous wood, for inftance, 
 though it may be at the fame time very porous, 
 will admit but little water. We may therefore 
 fay, that the different kinds of wood poffefs 
 different capacities for receiving water ; we 
 may even determine, by means of the augmen- 
 tation of their weights, what quantity of water 
 they have a£rually abforbed ; but, as we are ig- 
 norant how much water they contained, pre- 
 ‘ vious to immerfion, we cannot determine the 
 abfolute quantity they contain, after being ta- 
 ken out of the water. 
 
 The fame circum dances undoubtedly take 
 place, with bodies that are immerfed in caloric; 
 taking into- confideration, however, that water 
 is an incompreffible fluid, whereas caloric is, on 
 the contrary, endowed with very great elafti- 
 citv ; or, in other words, the particles of caloric 
 have a great tendency to feparate from each 
 other, when forced by any other power to ap- 
 proach; this difference muff of neceffity occa- 
 
 fiou 
 

 O F CHEMISTRY. 19 
 
 Son very confiderable diverfities in the refults 
 of experiments made upon thefe two fub- 
 dances. 
 
 Having eflablifhed thefe clear and fnnple 
 proportions, it will be very eafy to explain the 
 ideas which ought to be affixed to the follow- 
 ing expreffions, which are by no means fynoni- 
 mous, but pofiefs each a drift and determinate 
 meaning, as in the following definitions : 
 
 Free caloric , is that which is not combined in 
 any manner with any other body. But, as we 
 live in a fydem to which caloric has a very 
 drong adhefion, it follows that we are never 
 able to obtain it in the date of abfolute free- 
 dom. 
 
 Combined caloric , is that which is fixed in 
 bodies by affinity or eleftive attraftion, fo as to 
 form part of the fubdance of the body, even 
 part of its folidity. 
 
 By the expreffion fpecific caloric of bodies, we 
 underdand the refpeftive quantities of caloric 
 requifite for raifing a number of bodies of the 
 fame weight to an equal degree of tempera- 
 ture. This proportional quantity of caloric de- 
 pends upon the didance between the conditu- 
 ent particles of bodies, and their greater or 
 lefier degrees of cohedon ; and this didance, or 
 rather the fpace or void refulting from it, is, 
 as I have already obferved, called the capacity 
 cf bodies for containing caloric . 
 
 Heat , 
 
• 20 
 
 ELEMENTS 
 
 Heat , confidered as a fenfation, or, in other 
 words, fenfible heat, is only the effect produ- 
 ced upon our fentient organs, by the motion or 
 paffage of caloric, difengaged from the fur- 
 rounding bodies. In general, we receive im- 
 preffions only in coniequence of motion, and 
 we might eftablilh it as an axiom. That , with- 
 out MOTION, THERE IS NO SENSATION. This 
 general principle applies very accurately to the 
 feniations of heat and cold : When we touch a 
 cold body, the caloric which always tends to 
 become in equilibrio in all bodies, paffes from 
 our hand into the body we touch, which gives 
 us the feeling or fenfation of cold. The direct 
 contrary happens, when we touch a warm 
 body, the caloric then palling from the body 
 into our hand, produces the fenfation of heat. 
 If the hand and the body touched be of the 
 fame temperature, or very nearly fo, we receive 
 no imprefiion, either of heat or cold, becaufe 
 there is no motion or paffage of caloric ; and 
 thus no fenfation can ake place, without fome 
 correfoondent motion to occafion it. 
 
 When the thermometer rifes, it fhows, that 
 free caloric is entering into the furrounding 
 bodies: The thermometer, which is one of thefe, 
 receives its fhare in. proportion to its mafs, and 
 to the capacity which it poffeffes for containing 
 caloric. The change therefore which takes 
 place upon the thermometer, only announces a 
 
 change 
 
OF CHEMISTRY, 
 
 ti 
 
 change of place of the caloric in thofe bodies, 
 of which the thermometer forms one part ; it; 
 only indicates the portion of caloric received, 
 without being a meafure of the whole quantity 
 difengaged, difplaced, or abforbed. 
 
 The mod fimple and mod exadt method for 
 determining this latter point, is that defcribed 
 by Mr de la Place, in the Memoirs of the Aca- 
 demy, No. 1780, p. 364 ; a fummary explanation 
 of which will be found towards the conclufion 
 of this work. This method confifts in placing 
 a body, or a combination of bodies, from which 
 caloric is difengaging, in the midd of a hollow 
 fphere of ice ; and the quantity of ice melted 
 becomes an exadt meafure of the quantity of 
 caloric difengaged. It is poflible, by means of 
 the apparatus which we have caufed to be con- 
 drudted upon this plan, to determine, not as has 
 been pretended, the capacity of bodies for con- 
 taining heat, but the ratio of the increafe or di- 
 minution of capacity produced by determinate 
 degrees of temperature. It is eafy with the 
 fame apparatus, by means of divers combina- 
 tions of experiments, to determine the quantity 
 of caloric requilite for converting folid fub- 
 dances into liquids, and liquids into eladic aeri- 
 form fluids ; and, vice verfa , what quantity of 
 caloric efcapes from eladic vapours in changing 
 to liquids, and what quantity efcapes from li- 
 quids during their converfion into folids. Per- 
 haps, 
 
ELEMENTS 
 
 haps, when experiments have been made with 
 fufficient accuracy, we may one day be able to 
 determine the proportional quantity of caloric, 
 neceffary for producing the feveral fpecies of 
 gaffes. I fhall hereafter, in a feparate chapter, 
 give an account of the principal refults of fuch 
 experiments as have been made upon this head. 
 
 It remains, before finifhing this article, to 
 fay a few words relative to the caufe of the 
 elafticity of gaffes, and of fluids in the ftate of 
 vapour. It is by no means difficult to perceive 
 that this elafticity depends upon that of caloric, 
 which feems to be the inoft eminently elaftic 
 body in nature. Nothing is more readily con- 
 ceived, than that one body fhould become elaf- 
 tic by entering into combination with another 
 body poffeffed of that quality. We muft allow 
 that this is only an explanation of elafticity, by 
 an affumption of elafticity, and that we thus 
 only remove the difficulty one ftep farther, and 
 that the nature of elafticity, and the reafon for 
 caloric being elaftic, remains ftill unexplained. 
 Elafticity in the abftraft is nothing more than 
 that quality of the particles of bodies by which 
 they recede from each other when forced toge- 
 ther. This tendency in the particles of caloric 
 to feparate, takes place even at confiderable dif- 
 tances. We fhall be fatisfied of this, when we 
 confider that air is fufceptible of undergoing 
 great compreflion, which fuppofes that its par- 
 ticles 
 
OF CHEMISTRY. 
 
 *3 
 
 tides were previoufly very diftant from each 
 other ; for the power of approaching together 
 certainly fuppofes a previous diftance, at lead: 
 equal to the degree of approach. Confequent- 
 ]y 5 thofe particles of the air, which are already 
 confiderably diftant from each other, tend to 
 feparate Hill farther. In fad, if we produce 
 Boyle’s vacuum in a large receiver, the very 
 laft portion of air which remains fpreads itfelf 
 uniformly through the whole capacity of the 
 veffel, however large, fills it completely through- 
 out, and preffes every where againft its Tides : 
 We cannot, however, explain this effed, with- 
 out fuppofing that the particles make an effort 
 to feparate themfelves on every fide, and we 
 are quite ignorant at what diftance, or what 
 degree of rarefadion, this effort ceafes to ad. 
 
 Here, therefore, exifts a true repulfion be- 
 tween the particles of elaftic fluids ; at leaft, 
 circumftances take place exadly as if fuch a 
 repulfion adually exifted ; and we have very 
 good right to conclude, that the particles of 
 caloric mutually repel each other. When we 
 are once permitted to fuppofe this repelling 
 force, the rationale of the formation of gaffes, or 
 aeriform fluids, becomes perfedly fimple ; tho* 
 we muft, at the fame time, allow, that it is ex- 
 tremely difficult to form an accurate conception 
 of this repulfive force ading upon very minute 
 
 particles 
 
&4 ELEMENTS 
 
 particles placed at great diftances from eaclt 
 other. 
 
 It is, perhaps, more natural to fuppofe, that 
 the particles of caloric have a ftronger mutual 
 attraction than thofe of any other fubftance, 
 and that thefe latter particles are forced afunder 
 in confequence of this fuperior attraction be- 
 tween the particles of the caloric, which forces 
 them between the particles of other bodies, that 
 they may be able to reunite with each other. We 
 have fomewhat analogous to this idea in the phe- 
 nomena which occur when a dry fponge is dipt 
 into water : The fponge fwells ; its particles fepa- 
 rate from each other; and all its intervals are fill- 
 ed up by the water. It is evident, that the fponge, 
 in the aCt of lwelling, has acquired a greater 
 capacity for containing water than it had when 
 dry. But we cannot certainly maintain, that 
 the introduction of water between the particles 
 of the fponge has endowed them with a repul- 
 five power, which tends to leparat'e them from 
 each other ; on the contrary, the whole phe- 
 nomena are produced by means of attractive 
 powers ; and thefe are^r/?, The gravity of the- 
 water, and the power which it exerts on every 
 fide, in common with all other fluids ; 2 dly 9 
 The force of attraction which takes place be- 
 tween the particles of the water, caufmg them 
 to unite together ; $dly 9 The mutual attraction 
 of the particles of the fponge w r ith each other ; 
 
 and. 
 
*5 
 
 OF CHEMISTRY, 
 
 and, lajlly^ The reciprocal attraction which ex- 
 ills between the particles of the fponge and thofe 
 of the water. It is eafy to underftand, that the 
 explanation of this fad depends upon properly 
 appreciating the intenfity of, and connection be- 
 tween, thefe feveral powers. It is probable, 
 that the reparation of the particles of bodies, oc- 
 cafioned by caloric, depends in a fimilar man- 
 ner upon a certain combination of different at- 
 tractive powers, which, in conformity with the 
 Imperfe&ion of our knowledge, we endeavour 
 to exprefs by faying, that caloric communicates 
 a power of repulfion to the particles of bodies- 
 
 P 
 
 C H A F, 
 
* 6 ELEMENTS 
 
 G H A P. II 
 
 General Views relative to the Formation and Com - 
 pofition of our Atmofphere* 
 
 HESE views which I have taken of the 
 
 formation of elaftic aeriform fluids or 
 gaffes, throw great light upon the original for- 
 mation of the atmofpheres of the planets, and 
 particularly that of our earth. We readily con- 
 ceive, that it muff neceffarily confift of a mix- 
 ture of the following fubftances : Firjl , Of all 
 bodies that are fufceptible of evaporation, or, 
 more ftri&ly fpeaking, which are capable of re- 
 taining the ftate of aeriform elafticity in the 
 temperature of our atmofphere, and under a 
 preffure equal to that of a column of twenty- 
 eight inches of quickfilver in the barometer y 
 and, fecondly^ Of all fubftances, whether liquid 
 or folid, which are capable of being aiffolved 
 by this mixture of different gaffes. 
 
 The better to determine our ideas relating to 
 this fubjedl, which has not hitherto been fuffi- 
 ciently confidered, let us, for a moment, con- 
 ceive what change would take place in the va- 
 
 rious 
 
OF CHEMISTRY. 
 
 27 
 
 tious fubftances which compofe our earth, if its 
 temperature were fuddenly altered. If, for in- 
 ftance, we were fuddenly tranfported into the 
 Tegion of the planet Mercury, where probably 
 
 I the common temperature is much fuperior to 
 that of boiling water, the water of the earth, 
 and all the other fluids which are fufceptible of 
 the gaffeous ftate, at a temperature near to that 
 of boiling water, even quickfilver itfelf, would 
 become rarified ; and all thefe fubftances would 
 be changed into permanent aeriform fluids or 
 gaffes, f which would become part of the new at- 
 mofphere. Thefe new fpecies of airs or gaffes 
 would mix with thofe already exifting, and cer- 
 tain reciprocal decompofitions and new combi- 
 nations would take place, until fuch time as all 
 the ele&ive attra&ions or affinities fubfi fling 
 amongft all thefe new and old gaffeous fub- 
 ftances had operated fully ; after which, the ele- 
 mentary principles compofing thefe gaffes, being 
 faturated, would remain at reft. We muft attend 
 to this, however, that, even in the above hypo- 
 thetical fituation, certain bounds would occur to 
 the evaporation of thefe fubftances, produced by 
 that very evaporation itfelf; for as, in proportion 
 to the increafe of elaftic fluids, the preffure of the 
 atmofphere would be augmented, as every de- 
 gree of preffure tends, in fome meafure, to pre- 
 vent evaporation, and as even the moft evapa* 
 
 ruble 
 
ELEMENTS 
 
 rable fluids can refill the operation of a very 
 high temperature without evaporating, if pre- 
 vented by a proportionally ftronger compref- 
 fion, water and all other liquids being able to 
 fuflain a red heat in Papin’s digefter ; we mufl 
 admit, that the new atmofphere would at laft 
 arrive at finch a degree of weight, that the wa- 
 ter which had not hitherto evaporated would 
 ceafe to boil, and, of <confequence, would re- 
 main liquid ; fo that, even upon this fuppofi- 
 tion, as in all others of the fame nature, the in- 
 creafmg gravity of the atmofphere would find 
 certain limits which it could not exceed. We 
 might even extend thefe reflexions greatly far- 
 ther, and examine what change might be pro- 
 duced in fuch fituations upon (tones, falts, 
 and the greater part of the fufible fubflances 
 which compofe the mafs of our earth. Thefe 
 would be foftened, fufed, and changed into 
 fluids, &c. : But thefe fpeculations carry me 
 from my object, to which I haften to re- 
 turn. 
 
 By a contrary fuppofition to the one we have 
 been forming, if the earth were fuddenly tranf- 
 ported into a very cold region, the water which 
 at prefent compofes our feas, rivers, and fprings* 
 and probably the greater number of the fluids 
 we are acquainted with, would be converted 
 jntp folid mountains and hard rocks, at firfl di- 
 aphanous 
 
O F CHEMISTRY. 
 
 aphanous and homogeneous, like rock cryftal, 
 but which, in time, becoming mixed with fo- 
 reign and heterogeneous fubftances, would be- 
 come opake hones of various colours. In 
 this cafe, the air, or at leaft fome part of the 
 aeriform fluids which now compofe the mafs of 
 our atmofphere, would doubtlefs lofe its elafti- 
 city for want of a fufficient temperature to re- 
 tain them in that hate : They would return to 
 the liquid hate of exiftence, and new liquids 
 would be formed, of whofe properties we can. 
 not, at prefent, form the moft diftant idea. 
 
 Thefe two oppofite fuppofitions give a di- 
 ftinft proof of the following corollaries : Firji , 
 That /oddity , liquidity , and aeriform elajlicity , 
 are only three different ftates of exiftence of the 
 fame matter, or three particular modifications 
 which almofl all fubftances are fufceptible of 
 alfuming fucceflively, and which folely depend 
 upon the degree of temperature to which they 
 are expofed ; or, in other words, upon the 
 quantity of caloric with which they are penetra- 
 ted *. 2 dly. That it isextremely probable that 
 
 air is a fluid naturally exifting in a ftate of va- 
 pour 5 or, as we may better exprefs it, that our 
 atmofphere is a compound of all the fluids 
 
 which 
 
 * The degree of preflure which they undergo xnuft 
 be taken into account. E. 
 
ELEMENTS 
 
 3 ° 
 
 which are fufceptible of the vaporous or pe?* 
 manently elaftic date, in the ufual tempera* 
 ture, and under the common preffure. 3 dly % 
 That it is not impoflible we may difcover t 
 in our atmofphere, certain fubdances natural- 
 ly very compaft, even metals themfelves ; as 
 a metallic fubdance, for indance, only a little 
 more volatile than mercury, might exid in that 
 fituation. 
 
 Amongft the fluids with which we are ac- 
 quainted, fome, as water and alkohol, are] fu- 
 fceptible of mixing with each other in all pro- 
 portions ; whereas others, on the contrary, as 
 quickfllver, water, and oil, can only form a 
 momentary union ; and, after being mixed to- 
 gether, feparate and arrange themfelves accor- 
 ding to their fpecific gravities. The fame thing 
 ought to, or at lead may, take place in the at- 
 mofphere. It is poflible, and even extremely 
 probable, that, both at the firft creation, and 
 every day, gaffes are formed, which are diffi- 
 cultly mifcible with atmofpheric air, and are 
 continually feparating from it* If thefe gaffes 
 be fpecificaliy lighter than the general atmo- 
 fpheric mafs, they muff, of courfe, gather in the 
 higher regions, and form ftrata that float up- 
 on the common air. The phenomena which 
 accompany igneous meteors induce me to 
 believe, that there exifts in the upper parts 
 
 of 
 
6F CHEMISTRY. 
 
 5 * 
 
 of our atmofphere a ftratum of inflammable 
 fluid in contaft with thofe ftrata of air which 
 produce the phenomena of the aurora borealis 
 and other fiery meteors. — I mean hereafter to 
 purfue this fubjeQ; in a feparate treatife. 
 
 C H A Fa 
 
ELEMENTS 
 
 r st 
 
 CHAP. III. 
 
 Analyfis of Atmofpheric Air , and its Divifion into 
 two Elaftic Fluids ; the one fit for Refpiration 3 
 the other incapable of being refpired . 
 
 F ROM what has been premifed, it fol- 
 lows, that our atmofphere is compofed 
 of a mixture of every fubftance capable of re- 
 taining the gafleous or aeriform ftate in the 
 common temperature, and under the ufual 
 preffure which it experiences. Thefe fluids 
 conftitute a mafs, in fome meafure homogene- 
 ous, extending from the furface of the earth to 
 the greateft height hitherto attained, of which 
 the denfity continually decreafes in the inverfe 
 ratio of the fuperincumbent weight. But, as I 
 have before obferved, it is poflible that this firft 
 ftratum is furmounted by feveral others confid- 
 ing of very different fluids. 
 
 Our bufinefs, in this place, is to endeavour 
 to determine, by experiments, the nature of the 
 elaftic fluids which compofe the inferior ftra- 
 tum of air which we inhabit. Modern chemif- 
 try has made great advances in this refearch 5 
 and it will appear by the following details that 
 the analyfis of atmofpherical air has been more 
 
 rigo- 
 
DF CHEMISTRY. 
 
 33 
 
 rigcroufly determined than that of any other 
 Jubilance of the clafs. Chemiftry affords two 
 general methods of determining the condim- 
 ent principles of bodies, the method of ana- 
 lyfis, and that of fynthefis. When, for inflance, 
 by combining water with alkohol, we form the 
 fpecies of liquor called, in commercial language, 
 brandy or fpirit of wine, we certainly have a 
 right to conclude, that brandy, or fpirit of 
 wine, is compofed of alkohol combined with 
 water. We can produce the fame refult by the 
 analytical method ; and in general it ought to 
 be confidered as a principle in chemical fcience, 
 never to reft fatisfied without both thefe fpecies 
 of proofs. 
 
 We have this advantage in the analyfis of at- 
 mofpherical air, being able both to decompound 
 it, and to form it a new in the moft fatisfaclory 
 manner. I fhall, however, at prefent confine 
 myfelf to recount fuch experiments as are moft 
 conclufive upon this head ; and I may confider 
 moft of thefe as my own, having either firfl in- 
 vented them, or having repeated thofe of others, 
 with the intention of analyfing atmofphericai air, 
 in perfectly new points of view. 
 
 I took a matrafs (A, fig. 14. plate II.) of a- 
 bout 36 cubical inches capacity, having a long 
 neck B C D E, of fix or feven lines internal 
 diameter, and having bent the neck as in Plate 
 IV. Fig. 2. fo as to allow of its being placed in 
 
 E the 
 
34 
 
 ELEMENTS 
 
 the furnace MMNN, in fuch a manner that 
 the extremity of its neck E might be inferted 
 under a bell-glafs F G, placed in a trough of 
 quickfilver RRSS; I introduced four ounces 
 of pure mercury into the matrafs, and, by means 
 of a fyphon, e^haufted the air in the receiver 
 F G, fo as to raife the quickfilver to L L, and 
 I carefully marked the height at which it flood 
 by palling on a flip of paper. Having accurate- 
 ly noted the height of the thermometer and ba- 
 rometer, I lighted a fire in the furnace M M N N, 
 which I kept up almoft continually during 
 twelve days, fo as to keep the quickfilver always 
 almoft at its boiling point. Nothing remark- 
 able took place during the firlL day : The Mer- 
 cury, though not boiling, was continually eva- 
 porating, and covered the interior furface of th$ 
 veflels with fmall drops, at firft very minute, 
 which gradually augmenting to a fufficient fize, 
 fell back into the mafs at the bottom of the 
 vefiel. On the fecond day, fmall red particles 
 began to appear on the furface of the mercury, 
 which, during the four or five following days, 
 gradually increafed in fi?e and number ; after 
 which they ceafed to increafe in either refpe£t. 
 At the end cf twelve days, feeing that the cal- 
 cination of the mercury did not at all increafe, 
 I extinguifhed the fire, and allowed the veflels 
 to cool. The bulk of air in the body and neck 
 qf the matrafs, and in the belhglafs, reduced 
 
 a 
 
35 
 
 OF CHEMISTRY- 
 
 a medium of 28 inches of the barometer and 
 io° (54*5°) of the thermometer, at the com- 
 mencement of the experiment was about 50 
 cubical inches. At the end of the experiment 
 the remaining air, reduced to the fame medium 
 preffure and temperature, was only between 42 
 and 43 cubical inches 5 confequently it had lofl: 
 about y of its bulk. Afterwards, having col- 
 lected all the red particles, formed during the 
 experiment, from the running mercury in which 
 they floated, I found thefe to amount to 45 
 grains. 
 
 1 was obliged to repeat this experiment feve- 
 ral times, as it is difficult in one experiment both 
 to preferve the whole air upon which we ope^ 
 rate, and to collect the whole of the red parti* 
 cles, or calx of mercury, which is formed du^ 
 ring the calcination. It will often happen in 
 the fequel, that I (hall, in this manner, give in 
 one detail the refuits of two or three experi- 
 ments of the fame nature. 
 
 The air which remained after the calcination 
 of the mercury in this experiment, and which 
 was reduced to -f- of its former bulk, was no 
 longer fit either for refpiration or for combuf- 
 tion ; animals being introduced into it were 
 fuffocated in a few feconds, and when a taper 
 was plunged into it, it was extinguiffied as if it 
 had been immerfed into water. 
 
 1% 
 
ELEMENT® 
 
 3 6 
 
 In the next place, I took the 45 grains of red 
 matter formed during this experiment, which I 
 put into a final! glafs retort, having a proper 
 apparatus for receiving fuch liquid, or gafleous 
 product, as might be extracted : Having applied 
 a fire to the retort in a furnace, I obferved that, 
 in proportion as the red matter became heated, 
 the intenfity of its colour augmented. When 
 the retort was almoft red hot, the red matter 
 began gradually to decreafe in bulk, and in a 
 few minutes after it difappeared altogether ; at 
 the fame time 41 \ grains of running mercury 
 were collected in the recipient, and 7 or 8 cubi- 
 cal inches of elaftic fluid, greatly more capable 
 of fupporting both refpiration and combuflion 
 than atmofperical air, were colie&ed in the bell- 
 glafs. 
 
 A part of this air being put into a glafs tube 
 of about an inch diameter, fhowed the following 
 properties : A taper burned in it with a daz- 
 zling fplendour, and charcoal, inftead of con- 
 fuming quietly as it does in common air, burnt 
 with a flame, attended with a decrepitating 
 noife, like phofphorus, and threw out fuch a 
 brilliant light that the eyes could hardly endure 
 it. This fpecies of air was difcovered almoft 
 at the fame time by Mr Prieftley, Mr Scheele, 
 and myfelf. Mr Prieftley gave it the name of 
 dephlogijiicated air , Mr Seheele called it empyreal 
 tf/r. At firft I named it highly refpirable air> to 
 
 which 
 
OF CHEMISTRY* 
 
 n 
 
 ^hich has finee been fubftituted the term of 
 vital air . We fhall prefently fee what we ought 
 to think of thefe denominations. 
 
 In reflecting upon the circumftances of this 
 experiment, we readily perceive, that the mer- 
 cury, during its calcination, abforbs the falu- 
 brious and refpirable part of the air, or, to 
 fpeak more ftriftly, the bafe of this refpirable 
 part ; that the remaining air is a fpecies of me- 
 phitis, incapable of fupporting combuftion or 
 refpiration ; and confequently that atmofpheric 
 air is compofed of two elaftic fluids of different 
 and oppofite qualities. As a proof of this im- 
 portant truth, if we recombine thefe two elaftic 
 fluids, which we have feparately obtained in the 
 above experiment, viz. the 42 cubical inches of 
 mephitis, with the 8 cubical inches of refpirable 
 air, we reproduce an air precifely fimilar to that 
 of the atmofphere, and poflefling nearly the fame 
 power of fupporting combuftion and refpiration, 
 and of contributing to the calcination of metals. 
 
 Although this experiment furnilhes us with 
 a very Ample means of obtaining the two prin- 
 cipal elaftic fluids which compofe our atmo- 
 fphere, feparate from each other, yet it does not 
 give us an exaCt idea of the proportion in which 
 thefe two enter into its competition : For the 
 attra&ion of mercury to the refpirable part of 
 the air, or rather to its bafe, is not fufficiently* 
 ftrong to overcome all the circumftances which 
 
 oppofe 
 
ELEMENTS 
 
 3 * 
 
 oppofe this union. Thefe obdacles are the mttt 
 tual adhefion of the two condituent parts of 
 the atmofphere for each other, and the ele&ive 
 attra&ion which unites the bafe of vital air with 
 caloric ; in confequence of thefe, when the cal- 
 cination ends, or is at lead carried as far as is 
 poflible, in a determinate quantity of atmofphe- 
 ric air, there dill remains a portion of refpi- 
 rable air united to the mephitis, which the mer- 
 cury cannot feparate. I {hall afterwards {how, 
 that, at lead in our climate, the atmofpheric air 
 is compofed of refpirable and mephitic airs, in 
 the proportion of 27 and 73 ; and I {hall then 
 difcufs the caufes of the uncertainty which dill 
 exids with refpeft to the exa&nefs of that pro- 
 portion. 
 
 Since, during the calcination of mercury, air 
 is decompofed, and the bafe of its refpirable 
 part is fixed and combined with the mercury, it 
 follows, from the principles already edablilhed, 
 that caloric and light mud be difengaged du- 
 ring the procefs : But the two following caufes 
 prevent us from being fenfibie of this taking 
 place : As the calcination lads during feveral 
 days, the difengagement of caloric and light* 
 fpread out in a confiderable fpace of time, be- 
 comes extremely fmall for each particular mo- 
 ment of that time, fo as not to be perceptible % 
 and, in the next place, the operation being car- 
 ried on by means of fire in a furnace, the heat 
 
 produced 
 
OF CHEMISTRY. 
 
 S) 
 
 produced by the calcination itfelf becomes con* 
 founded with that proceeding from the furnace. 
 I might add the refpirable part of the air, or 
 rather its bafe, in entering into combination 
 with the mercury, does not part with all the 
 caloric which it contained, but (till retains a part 
 of it after forming the new compound ; but the 
 difcuffion of this point, and its proofs from ex- 
 periment, do not belong to this part of our 
 fubjeft. 
 
 It is, however, eafy to render this disengage- 
 ment of caloric and light evident to the fenfes, 
 by caufing the decomposition of air to take 
 place in a more rapid manner. And for this 
 purpofe, iron is excellently adapted, as it pof- 
 fefles a much ftronger affinity for the bafe of 
 refpirable air than mercury. The elegant ex- 
 periment of Mr Ingenhouz, upon the combuf- 
 tion of iron, is well known. Take a piece of 
 fine iron v/ire, twitted into a Spiral, (BC, Plate 
 IV. Fig. 17.) fix one of its extremities B into 
 the cork A, adapted to the neck of the bottle 
 DEFG, and fix to the % other extremity of the 
 wire C, a fmall morfel of tinder. Matters be- 
 ing thus prepared, fill the bottle DEFG with 
 air deprived of its mephitic part ; then light 
 the tinder, and introduce it quickly with the 
 wire upon wffiich it is fixed, into the bottle 
 which you flop up with the cork A, as is fhown 
 in the figure (17 Plate IV.) The inftant the 
 
 tinder 
 
ELEMENTS 
 
 * 
 
 tinder comes into contact with the vital auf 
 it begins to burn with great intenfity ; and, 
 communicating the inflammation to the iron- 
 wire, it too takes fire, and burns rapidly, throw- 
 ing out brilliant fparks, which fall to the bot- 
 tom of the veffel in rounded globules, which 
 become black in cooling, but retain a degree of 
 metallic fplendour. The iron thus burnt is 
 more brittle even than glafs, and is eafily redu- 
 ced into powder, and is ftill attractable by the 
 magnet, though not fo powerfully as it was be- 
 fore combuftion. As Mr ingenhouz has nei- 
 ther examined the change produced on iron, nor 
 upon the air by this operation, I have repeated 
 the experiment under different circumftances, 
 in an apparatus adapted to anfwer my particu- 
 lar views, as follows. 
 
 Having filled a bell glafs (A, Plate IV. Fig. 3.) 
 of about fix pints meafure, with pure air, or the 
 highly refpirable pan of air, I tranfporred this jar 
 by means of a very flat veffel, into a quickfilver 
 bath in the bafon BC, and I took care to ren- 
 der the furface of the mercury perfectly dry both 
 within and without the jar with blotting paper. 
 1 then provided a fmall capfule of china-ware D, 
 very flat and open, in which I placed fome fmall 
 pieces of iron, turned fpirally, and arranged in 
 fuch a way as feemed moft favourable for the 
 combuftion being communicated to every part. 
 To the end of one of thefe pieces of iron was 
 
 fixed 
 
 ! 
 
OF CHEMISTRY. 
 
 4t 
 
 fkt;d a fmall morfel of tinder, to which was 
 added about the fixteenth part of a grain of 
 phofphorus, and, by railing the bell-glafs a lit- 
 tle, the china capfule, with its contents, were 
 introduced into the pure air. I know that, by 
 this means, fome common air mult mix with 
 the pure air in the glafs ; but this, when it is 
 done dexteroufly, is fo very trifling, as not to in- 
 jure the fuccefs of the experiment. This being 
 done, a part of the air is fucked out from the 
 bell-glafs, by means of a fyphon GHI, fo as to 
 raife the mercury within the glafs to EF ; and, 
 to prevent the mercury from getting into the 
 fyphon, a fmall piece of paper is twilled round 
 its extremity. In fucking out the air, if the 
 motion of the lungs only be ufed, we cannot 
 make the mercury rife above an inch or an 
 inch and a half; but, by properly ufing the 
 mufcles of the mouth, we can, without difficul- 
 ty, caufe it to rife fix or feven inches. 
 
 I next took an iron wire, (MN, Plate IV. 
 Fig. 1 6.) properly bent for the purpofe, and 
 making it red hot in the fire, palled jit through 
 the mercury into the receiver, and brought it 
 in contaft with the fmall piece of phofphorus 
 attached to the tinder* The phofphorus in- 
 ! ftantly takes Are, which communicates to the 
 tinder, and from that to the iron. When 
 I the pieces have been properly arranged, the 
 whole iron burns, even to the laft particle, 
 F throwing 
 
42 
 
 ELEMENTS 
 
 throwing out a white brilliant light fimilar to that 
 of Chinefe fireworks. The great heat produced 
 by this combuftion melts the iron into round 
 globules of different fizes, molt of which fall 
 into the China cup ; but fome are thrown out 
 of it, and fwim upon the furface of the mer- 
 cury. At the beginning of the combuftion, 
 there is a flight augmentation in the volume of 
 the air in the bell-glafs, from the dilatation 
 caufed by the heat ; but, prefently afterwards, a 
 rapid diminution of the air takes place, and the 
 mercury rifes in the glafs ; infomuch that, when 
 the quantity of iron is fufficient, and the air o- 
 perated upon is very pure, almoft the whole 
 air employed is abforbed. 
 
 It is proper to remark in this place, that, un- 
 lefs in making experiments for the purpofe of 
 difcovery, it is better to be contented with burn- 
 ing a moderate quantity of iron ; for, when this 
 experiment is pufhed too far, fo as to abforb 
 much of the air, the cup D, which floats upon 
 the quickfilver, approaches too near the bottom 
 of the belhglafs ; and the great heat produced, 
 which is followed by a very fudden cooling, oc- 
 cafioned by the contadl of the cold mercury, is 
 apt to break the glafs. In which cafe, the fud- 
 den fall of the column of mercury, which hap- 
 pens the moment the Ieaft flaw is produced in 
 the glafs, caufes fuch a wave, as throws a great 
 part of the quickfilver from the bafon. To a- 
 
 void 
 
OF CHEMISTRY* 
 
 43 
 
 void this inconvenience, and to enfure fuccefs 
 to the experiment, one grofs and a half of iron 
 is fufficient to burn in a bell-glafs, which holds 
 about eight pints of air. The glafs ought like- 
 wife to be itrong, that it may be able to bear 
 the weight of the column of mercury which it 
 has to fupport. 
 
 By this experiment, it is not poilible to deter- 
 mine, at one time, both the additional weight 
 acquired by the iron, and the changes which 
 have taken place in the air. If it is wifhed to af- 
 certain what additional weight has been gained 
 by the iron, and the proportion between that 
 and the air abforbed, we mud carefully mark 
 upon the bell-glafs, with a diamond, the height 
 of the mercury, both before and after the expe- 
 riment *. After this, the fyphon GH, PL IV. 
 fig. 3.) guarded, as before, with a bit of paper, 
 to prevent its filling with mercury, is to be in- 
 troduced under the bell-glafs, having the thumb 
 placed upon the extremity, G, of the fyphon, to 
 regulate the paflage of the air ; and by this 
 means the air is gradually admitted, fo as to let 
 the mercury fall to its level. This being done, 
 the bell-glafs is to be carefully removed, the 
 
 globules 
 
 * It will likewife be neceflary to take care that the 
 air contained in the glais, both before and after the 
 experiment, be reduced to a common temperature and 
 preffure, otherwife the refults of the following, calcula- 
 tions will be fallacious; — E. 
 
44 
 
 ELEMENTS 
 
 globules of melted iron contained in th$ cup, 
 and thofe which have been fcattered about, and 
 fwim upon the mercury, are to be accurately 
 colle&ed, and the whole is to be weighed. The 
 iron will be found in that (late called martial 
 etkiops by the old chemifts, poffeffmg a degree 
 of metallic brilliancy, very friable, and readily 
 reducible into powder, under the hammer, or 
 with a peftle and mortar. If the experiment 
 has fucceeded well, from ioo grains of iron will 
 be obtained 1 35 or 136 grains of ethiops, which 
 is an augmentation of 35 per cent. 
 
 If all the attention has been paid to this ex- 
 periment which it deferves, the air will be found 
 diminiihed in weight exactly equal to what the 
 iron has gained. Having therefore burnt 1 00 
 grains of iron, which has acquired an addition- 
 al weight of 35 grains, the diminution of air 
 will be found exa&ly 70 cubical inches ; and 
 it will be found, in the fequel, that the weight 
 of vital air is pretty nearly half a grain for each 
 cubical inch ; fo that, in effect, the augmenta- 
 tion of weight in the one exactly coincides with 
 the lofs of it in the other. 
 
 I fhall obferve here, once for all, that, in eve- 
 ry experiment of this kind, the preffure an <t 
 temperature of the air, both before and after 
 the experiment, muff be reduced, by calcula- 
 tion, to a common ftandard of io° (54.5 0 ) of 
 the thermometer, and 28 inches of the barome- 
 ter. 
 
OF CHEMISTRY. 
 
 U 
 
 ter. Towards the end of this work, the man- 
 ner of performing this very neceffary redu&ion 
 will be found accurately detailed. 
 
 If it be required to examine the nature of the 
 air which remains after this experiment, we 
 mull operate in a fomewhat different manner. 
 After the combuftion is finifhed, and the veffels 
 have cooled, we firll take out the cup, and the 
 burnt iron, by introducing the t hand through 
 the quickfilver, under the bell-glafs j we next 
 introduce fome folution of potafh, or cauftic al- 
 kali, or of the fulphuret of potafh, or fuch other 
 fubflance as is judged proper for examining 
 their a&ion upon the refiduum of air. I fhali, 
 in the fequel, give an account of thefe methods 
 of analyfing air, when I have explained the na- 
 ture of thefe different fubftances, which are only 
 here in a manner accidentally mentioned. Af- 
 ter this examination, fo much water mud be 
 let into the glafs as will difplace the quickfil- 
 ver, and then, by means of a fhallow difli placed 
 below the bell-glafs, it is to be removed into 
 the common water pneumato-chemical appara- 
 tus, where the air remaining may be examined 
 at large, and with great facility. 
 
 When very foft and very pure iron has been 
 employed in this experiment, and, if the com- 
 buftion has been performed in the pureft refpi- 
 rable or vital air, free from all admixture of the 
 noxious or mephitic part, the air which remains 
 
 after 
 
elements 
 
 after the combuftion will be found as pure as it 
 was before ; but it is difficult to find iron en- 
 tirely free from a fmall portion of charry mat- 
 ter, which is chiefly abundant in fteel. It is 
 likewife exceedingly difficult to procure the pure 
 air perfectly free from fome admixture of me- 
 phitis, with which it is almoft always contami- 
 nated ; but this fpecies of noxious air does not, 
 in the fmalleft degree, difturb the refult of the 
 experiment, as it is always found at the end 
 exa&ly in the fame proportion as at the begin- 
 ning. 
 
 I mentioned before, that we have two ways 
 of determining the conftituent parts of atmo- 
 fpheric air, the method of analyfis, and that by 
 fynthefis. The calcination of mercury has fur- 
 nifhed us with an example of each of thefe me- 
 thods, fince, after having robbed the refpirable 
 part of its bafe, by means of the mercury, we 
 have reftored it, fo as to recompofe an air pre- 
 cifely fimilar to that of the atmofphere. But 
 we can equally accomplifh this fynthetic compo- 
 fition of atmofpheric air, by borrowing the ma- 
 terials of which it is compofed from different 
 kingdoms of nature. We fhall fee hereafter 
 that, when animal fubftances are diffolved in 
 the nitric acid, a great quantity of gas is difen- 
 gaged, which extinguifhes light, and is unfit 
 for animal refpiration, being exactly fimilar to 
 the noxious or mephitic part of atmofpheric air. 
 And, if we take 73 parts, by weight, of this e- 
 
 laftic 
 
OF CHEMISTRY. 
 
 
 laflic fluid, and mix it with 27 parts of highly 
 refpirable air, procured from calcined mercury, 
 we will form an elaftic fluid precifely fimilar to 
 atmofpheric air in all its properties. 
 
 There are many other methods of feparating 
 the refpirable from the noxious part of the at- 
 mofpheric air, which cannot be taken notice of 
 in this part, without anticipating information, 
 which properly belongs to the fubfequent chap- 
 ters. The experiments already adduced may 
 fuffice for an elementary treatife ; and, in mat- 
 ters of this nature, the choice of our evidences 
 is of far greater confequence than their num- 
 ber. 
 
 I fliall clofe this article, by pointing out the 
 property which atmofpheric air, and all the 
 known gaffes, poffefs of diffolving water, which 
 is of great confequence to be attended to in 
 all experiments of this nature. Mr Sauffure 
 found, by experiment, that a cubical foot of at- 
 mofpheric air is capable of holding 1 2 grains 
 of water in folution : Other gafles, a£> the car- 
 bonic acid, appear capable of diffolving a great- 
 er quantity ; but experiments are (fill wanting 
 by which to determine their feveral propor- 
 tions. This water, held in folution by gaffes, 
 gives rife to particular phenomena in many 
 experiments, which require great attention, 
 and which has frequently proved the fource of 
 great errors to chemifts in determining the re- 
 sults of their experiments. 
 
 CHAP. 
 
ELEMENTS 
 
 
 i 
 
 CHAP. IV. 
 
 Nomenclature of the feveral Conjlituent Parts of 
 Atmofpheric Air . 
 
 H ITHERTO I have been obliged to make 
 ufe of circumlocution, to exprefs the na- 
 ture of the feveral fubftances which conftitute our 
 atmofphere, having provifionally ufed the terms 
 of refpirable and noxious , or non-refpirabl? parts 
 of the air. But the inveftigations I mean to 
 undertake require a more direft mode of ex- 
 preflion ; and, having now endeavoured to give 
 fimple and diftinft ideas of the different fub- 
 ftances which enter into the compofition of the 
 atmofphere, I fhall henceforth exprefs thefe ideas 
 by w T ords equally fimple. 
 
 The temperature of our earth being very 
 near to that at which water becomes folid, and 
 reciprocally changes from folid to fluid, and 
 as this phenomenon takes place frequently un- 
 der our obfervation, it has very naturally folr 
 lowed, that, in the languages of at lead every 
 climate fubje&ed to any degree of winter, a 
 term has been ufed for fignifying water in the 
 ftate of folidity, when deprived of its caloric. 
 The fame, however, has not been found necef- 
 
 fary 
 
OF CHEMISTRY* 
 
 49 
 
 fary with refpeft to water reduced to the hate 
 of vapour by an additional dofe of caloric ; fince 
 :thofe perfons who do not make a particular 
 * ftudy of obje&s of this kind, are ftill ignorant 
 l that water, when in a temperature only a little 
 (above the boiling heat, is changed into an elaf- 
 I tic aeriform fluid, fufceptible, like all other gaf- 
 |fes, of being received and contained in veflels, 
 and preferving its galfeous form fo long as it 
 remains at the temperature of 8o°(2i2°), and 
 under a preflure not exceeding 28 inches of the 
 | mercurial barometer. As this phenomenon has 
 ; not been generally obferved, no language has 
 I ufed a particular term for exprefling water in 
 i this Aate * ; and the fame thing occurs with all 
 1 fluids, and all fubflances, which do not evapo- 
 i rate in the common temperature, and under the 
 ufual preflure of our atmofphere. 
 
 For flmiiar reafons, names have not been given 
 to the liquid or concrete flates of molt of the 
 aeriform fluids : Thefe were not known to arife 
 from the combination of caloric with certain 
 bafes ; and, as they had not been feen either in 
 the liquid or folid flates, their exiflence, under 
 thefe forms* was even unknown to natural phi- 
 lofophers. 
 
 G We 
 
 * In Englifh, the word ftean 2 is exclufivdy appro- 
 priated to water in the ft ate of vapour. E 
 
50 ELEMENTS 
 
 We have not pretended to make any altera* 
 tion upon fuch terms as are fan&ified by ancient 
 cuftom ; and, therefore, continue to ufe the words- 
 water and ice in their common acceptation : We 
 likewife retain the word air , to exprefs that col- 
 lection of elaftic fluids which compofes our at- 
 mOfphere ; but we have not thought it necef- 
 fary to preferve the fame refpeCt for modern 
 terms, adopted by latter philofophers, having 
 confidered ourfelves as at liberty to rejeCt fuch 
 as appeared liable to occaflon erroneous ideas 
 of the fubftances they are meant to exprefs, and 
 . either to fubftitute new terms, or to employ 
 the old ones, after modifying them in fuch a 
 manner as to convey more determinate ideas. 
 New words have been drawn, chiefly from the 
 Greek language, in fuch a manner as to make 
 their etymology convey fome idea of what was 
 meant to be reprefented ; and thefe we have 
 always endeavoured to make fhort, and of fuch 
 a nature as to be changeable into adjeCtives and 
 verbs. 
 
 Following thefe principles, we have, after Mt 
 M acquer’s example, retained the term gas , em- 
 ployed by Vanhelmont, having arranged the nu- 
 merous clafs of elaftic aeriform fluids under that 
 name, excepting only atmofpheric air. Gas , 
 therefore, in our nomenclature, becomes a ge- 
 neric term, exprefling the fulleft degree of fa- 
 turation in any body with caloric j being, in 
 
 fad:,, 
 

 OF CHEMISTRY. 51 
 
 fad, a term expreffive of a mode of exidence. 
 To didinguifh each fpecies of gas, we employ a 
 •fecond term from the name of the bafe, which, 
 Saturated with caloric, forms each particular gas. 
 Thus, we name water combined to faturation 
 with caloric, fo as to form an elaflic fluid, aque- 
 ous gas ; ether, combined in the fame manner, 
 etherial gas ; the combination of alkohoi with 
 caloric, becomes alkoholic gas ; and, following 
 the fame principles, we have muriatic acid gas , 
 ammoniacal gas , and lo on of every fub (lance 
 fufceptible of being combined with caloric, in 
 •fuch a manner as to aflTume the gafleous or elaf- 
 tic aeriform date. 
 
 We have already feen, that the atmofpheric^ 
 air is compofed of two gaffes, or aeriform fluids, 
 one of which is capable, by refpiration, of con- 
 tributing to animal life, and in which metals 
 are calcinable, and combudible bodies may 
 burn ; the other, on the contrary, is endowed 
 with directly oppoflte qualities ; it cannot be 
 breathed by animals, neither will it admit of 
 the combudion of inflammable bodies, nor of 
 the calcination of metals. We have given to 
 the bafe of the former, or refpirable portion of 
 the air, the name of oxygen , from acidum , 
 and yuniAxh gignor ; becaufe, in reality, one of 
 the mod general properties of this bafe is to 
 form acids, by combining with many different 
 fubdances. The union of this bafe with calo- 
 
 ric 
 
5 * 
 
 ELEMENTS 
 
 ric we term oxygen gas , which is the fame 
 with what was formerly called pure , or vital air . 
 The weight of this gas, at the temperature of 
 io° (54.50), and under a prefiure equal to 28 
 inches of the barometer, is half a grain for each 
 cubical inch, or one ounce and a half to each 
 cubical foot. 
 
 The chemical properties of the noxious por- 
 tion of aimofpheric air being hitherto but little 
 known, we have been fatisfied to derive the 
 name of its bafe from its known quality of kil- 
 ling fuch animals as are forced to breathe it, 
 giving it the name of azote, from the Greek 
 privitive panicle * and vita; hence the name 
 of the noxious part of atmofpheric air is azotic 
 gas ; the weight of which, in the fame tempe- 
 rature, and under the fame preffure, is 1 cz~ 
 2 gros. and 48 grs. to the cubical foot, or 
 0.4444 of a grain to the cubical inch. We 
 cannot deny that this name appears fomewhat 
 extraordinary ; but this mud be the cafe with 
 ail new terms, which cannot be expected to be- 
 come familiar until they have been fome time 
 in ufe. We long endeavoured to find a more 
 proper defignation without fuccefs ; it was at 
 firfl propofed to call it alkaiigen gas , as, from 
 the experiments of Mr Berthollet, it appears to 
 enter into the compofition of ammoniac, or vo- 
 latile alkali ; but then, we have as yet no proof 
 of its making one of the conftituent elements of 
 
 the 
 
OF CHEMISTRY, 
 
 53 
 
 
 the other alkalies ; befide, it is proved to com- 
 pofe a part of the nitric acid, which gives as 
 good reafon to have called it nitrigen . For thefe 
 reafons, finding it neceiTary to rejedt any name 
 upon fyftematic principles, we have confidered 
 that we run no rifk of miflake in adopting the 
 terms of azote , and azotic gas , which only ex- 
 . prefs a matter of fadt, or that property which it 
 pofleffes, of depriving fuch animals as breathe it 
 of their lives. 
 
 I fhould anticipate fubjedts more properly re- 
 ferved for the fubfequent chapters, were I in 
 this place to enter upon the nomenclature of the 
 feveral fpecies of gafles : It is fufficient, in this 
 part of the work, to eftablifh the principles up- 
 on which their denominations are founded. The 
 principal merit of the nomenclature we have 
 adopted is, that, when once the fimple elemen- 
 tary fubftance is diflinguifhed by an appropri- 
 ate term, the names of all its compounds derive 
 readily, and neceflarily, from this firfl denomi- 
 nation. 
 
 CHAP. 
 
*1 
 
 ELEMENTS 
 
 CHAP. V. 
 
 Of the Decompofition of Oxygen Gas by Sulphur * 
 Phofphorus , and Charcoal — and of the Format 
 tion of Acids in general • 
 
 3 N performing experiments, it is a neceffary 
 principle, which ought never to be deviated 
 from, that they be fimplified as much as poflible, 
 and that every circumftance capable of render- 
 ing heir refults complicated be carefully remo- 
 ved. Wherefore, in the experiments which 
 form the object of this chapter, we have never 
 employed atmofpheric air, which is not a fimpie 
 fubftance. It is true, that the azotic gas, which 
 forms a part of its mixture, appears to be mere- 
 ly paffive during combuftion and calcination ; 
 but, befides that it retards thefe operations 
 very confiderably, we are not certain but it may 
 even alter their refults in fome circumftances ; 
 for which reafon, I have thought it neceffary to 
 remove even this poffible caufe of doubt, by on- 
 ly making ufe of pure oxygen gas in the follow- 
 ing experiments, which fhow the effedls produ- 
 ced by combuftion in that gas ; and I fhall ad- 
 vert to fuch differences as take place in the re- 
 fults of thefe, when the oxygen gas, or pure 
 
 vital 
 
OF CHEMISTRY. £f 
 
 vital air, is mixed, in different proportions, with 
 azotic gas. 
 
 Having filled a bell-glafs (A. PI. iv. fig. 3), 
 of between five and fix pints meafure, with oxy- 
 gen gas, I removed it from the water trough, 
 where it was filled, into the quickfilver bath, 
 by means of a fhallow glafs difh flipped under- 
 neath, and having dried the mercury, I introdu- 
 ced 61-5- grains of Kunkel’s phofphorus in two 
 little China cups, like that reprefented at D, 
 fig. 3. under the glafs A ; and that I might fet 
 fire to each of the portions of phofphorus fepa- 
 rately, and to prevent the one from catching 
 fire from the other, one of the difhes was cover- 
 ed with a piece of flat glafs. I next raifed the 
 quickfilver in the bell-glafs up to E F, by fuc- 
 king out a fufficient portion of the gas by 
 means of the fyphon G H I. After this, by 
 means of the crooked iron wire (fig. 16. ), made 
 red hot, I fet fire to the two portions of phof- 
 phorus fucceflively, firft: burning that portion 
 which was not covered with the piece of glafs., 
 The combuflion was extremely rapid, attended 
 with a very brilliant flame, and confiderable dif- 
 engagement of light and heat. In confequence 
 of the great heat induced, the gas was at firft 
 much dilated, but foon after the mercury re- 
 turned to its level, and a confiderable abforp- 
 tion of gas took place } at the fame time, the 
 
 whole 
 
;<S ELEMENT S 
 
 whole infide of the glafs became covered witlj 
 white light flakes of concrete phofphoric acid. 
 
 At the beginning of the experiment, the 
 quantity of oxygen gas, reduced, as above di- 
 rected, to a common ftandard, amounted to 162 
 cubical inches ; and, after the combuftion was 
 finifhed, only 23^ cubical inches, likewife redu- 
 ced to the ftandard, remained; fo that the quan- 
 tity of oxygen gas abforbed during the com- 
 buftion was 1 38-J cubical inches, equal to 69.375 
 grains. 
 
 A part of the phofphorus remained uncon- 
 fumed in the bottom of the cups, which being 
 wafhed on purpofe to feparate the acid, weigh- 
 ed about 1 6 \ grains; f6 that about 45 grains 
 of phofphorus had been burned : But, as it is 
 hardly poflible to avoid an error of one or two 
 grains, I leave the quantity fo far qualified. 
 Hence, as nearly 45 grains of phofphorus had, 
 in this experiment, united with 69.375 grains 
 of oxygen, and as no gravitating matter could 
 have efcaped through the glafs, we have a right 
 to conclude, that the weight of the fubftance re- 
 fulting from the combuftion in form of white 
 flakes, muft equal that of the phofphorus and 
 oxygen employed, which amounts to 1 14.375 
 grains. And we fhall prefently find, that thefe 
 flakes confided entirely of a folid or concrete 
 acid. When we reduce thefe weights to hun- 
 dredth parts, it will be found, that 100 parts of 
 
 phofphorus 
 
OF CHEMISTRY. 
 
 5 7 
 
 phofphorus require 154 parts of oxygen for fa- 
 turation, and that this combination will produce 
 254 parts of concrete phofphoric acid, in form 
 of white fleecy flakes. 
 
 This experiment proves, in the mod convin- 
 cing manner, that, at a certain degree of tem- 
 perature, oxygen poflefles a ffronger elective at- 
 traction, or affinity, for phofphorus than for ca- 
 loric ; that, in confequence of this, the phof- 
 phorus attracts the bafe of oxygen gas from the 
 caloric, which, being fet free, fpreads itfelf over 
 the furrounding bodies. But, though this ex- 
 periment be fo far perfectly conciufive, it is not 
 fufflciently rigorous, as, in the apparatus de- 
 ferred, it is impofiible to afeertain the weight 
 of the flakes of concrete acid which are formed ; 
 we can therefore only determine this by calcu- 
 lating the weights of oxygen and phofphorus 
 employed ; but as, in phyfics, and in chemiftry, 
 it is not allowable to fuppofe what is capable of 
 being afeertained by direCt experiment, 1 thought 
 it neceflary to repeat this experiment, as follows, 
 upon a larger fcale, and by means of a different 
 apparatus, 
 
 I took a large glafs baloon (A. PI. iv. fig. 4.) 
 with an opening three inches diameter, to which 
 was fitted a cryftal ftopper ground with emery, 
 and pierced with two holes for the tubes yyy 9 
 xxx. Before fhutting the baloon with its ftop- 
 per, I introduced the fupport BC, furmounted 
 H by 
 
58 ELEMENTS 
 
 by the china cup D, containing 150 grs . o£ 
 phosphorus ; the (topper was then fitted to the 
 opening of the baloon, luted with fat lute, and 
 covered with flips of linen fpread with quick- 
 lime and white of eggs : When the lute was 
 perfectly dry, the weight of the whole appara- 
 tus was determined to within a grain, or a grain 
 and a half. I next exhaufted the baloon, by 
 means of an air pump applied to the tube xxx, 
 and then introduced oxygen gas by means of 
 the tube yyy, having a flop cock adapted to it. 
 This kind of experiment is mod readily and 
 mod exactly performed by means of the hydro- 
 pneumatic machine defcribed by Mr Meufnier 
 and me in the Memoirs of the Academy for 
 1782, pag. 466. and explained in the latter 
 part of this work, with feveral important addi- 
 tions and corrections fmce made to it by Mr 
 Meufnier. With this inflrument we can readi- 
 ly afcertain, in the moft exaCt manner, both the 
 quantity of oxygen gas introduced into the ba- 
 loon, and the quantity confumed during the 
 courfe of the experiment. 
 
 When all things were properly difpofed, I 
 fet fire to the phofphorus with a burning glafs. 
 The combuflion was extremely rapid, accom- 
 panied with a bright flame, and much heat ; as 
 the operation went on, large quantities of white 
 flakes attached themfeives to the inner furface 
 of the baloon, fo that at laft it was rendered 
 
 quite 
 
OF CHEMISTRY. 59 
 
 quite opake. The quantity of thefe flakes at 
 laft became fo abundant, that, although frefli 
 oxygen gas was continually fupplied, which 
 ought to have fupported the combuftion, yet the 
 phofphorus was foon extinguifhed. Having al- 
 lowed the apparatus to cool completely, I hrft 
 afcertained the quantity of oxygen gas employ- 
 ed, and weighed the baloon accurately, before 
 it was opened. I next wafhed, dried, and 
 weighed the fmall quantity of phofphorus re- 
 maining in the cup, on purpofe to determine the 
 whole quantity of phofphorus confumed in the 
 experiment ; this refiduum of the phofphorus 
 was of a yellow ochrey colour. It is evident, 
 that by thefe feveral precautions, I could eafily 
 determine, ift, the weight of the phofphorus 
 confumed ; 2d, the weight of the flakes pro. 
 duced by the combuftion ; and, 3d, the weight 
 of the oxygen which had combined with the 
 phofphorus. This experiment gave very nearly' 
 the fame refults with the former, as it proved 
 that the phofphorus, during its combuftion, had 
 abforbed a little more than one and a half its 
 weight of oxygen ; and I learned with more 
 certainty, that the weight of the new fubftance, 
 produced in the experiment, exactly equalled 
 the fum of the weights of the phofphorus con- 
 fumed, and oxygen abforbed, which indeed was 
 eafily determinable a priori . If the oxygen gas 
 employed be pure, the refiduum after combuf- 
 tion 
 
6o 
 
 ELEMENTS 
 
 tion is as pure as the gas employed ; this proves 
 that nothing efcapes from the phofphorus, ca- 
 pable of altering the purity of the oxygen gas, 
 and that the only adlion of the phofphorus is to 
 feparate the oxygen from the caloric, with 
 which it was before united. 
 
 I mentioned above, that when any combufti- 
 ble body is burnt in a hollow fphere of ice, or 
 in an apparatus properly conflrudled upon that 
 principle, the quantity of ice melted during the 
 combufiion is an exadl meafure of the quan- 
 tity of caloric difengaged. Upon this head, 
 the memoir given by M. de la Place and me, 
 A°. 1780, p. 355, may be confulted. Having 
 fubmitted the combufiion of phofphorus to this 
 trial, we found that one pound of phofphorus 
 melted a little more than 100 pounds of ice 
 during its combufiion. 
 
 The combufiion of phofphorus fucceeds equal- 
 ly well in atmofpheric air as in oxygen gas, 
 with this difference, that the combufiion is vafl- 
 ly flower, being retarded by the large propor- 
 tion of azotic gas mixed with the oxygen gas, 
 and that only about one-fifth part of the air 
 employed is abforbed, becaufe as the oxygen 
 gas only is abforbed, the proportion of the 
 azotic gas becomes fo great toward the clofe of 
 the experiment, as to put an end to the com- 
 bufiion. 
 
 I 
 
\ 
 
 OF CHEMISTRY, 6t 
 
 I have already fhown, that phofphorus is 
 changed by combuftion into an extremely light, 
 white, flakey matter ; and its properties are 
 entirely altered by this transformation : Front 
 being infoluble in water, it becomes not only 
 foluble, but fo greedy of moifture, as to attradk 
 the humidity of the air with aftonifhing rapidi- 
 ty ; by this means it is converted into a liquid, 
 confiderably more denfe, and of more fpecific 
 gravity than water. In the date of phofphorus 
 before combuftion, it had fcarcely any fenfible 
 tafte, by its union with oxygen it acquires an 
 extremely fharp and four tafte : in a word, 
 from one of the clafs of combuftible bodies, it 
 is changed into an incombuftible fubftance, 
 and becomes one of thofe bodies called acids. 
 
 This property of a combuftible fubftance to 
 be converted into an acid, by the addition of 
 oxygen, we fhall prefently find belongs to a 
 great number of bodies : Wherefore, ftri£t lo- 
 gic requires that we fhould adopt a common 
 term for indicating all thefe operations which 
 produce analogous refults ; this is the true way 
 to fimplify the ftudy of fcience, as it would be 
 quite impoflible to bear all its fpecifical details 
 in the memory, if they were not claflically 
 arranged. For this reafon, we fhall diftinguifh 
 this converfion of phofphorus into an acid, by 
 its union with oxygen, and in general every 
 combination of oxygen with a combuftible fub* 
 
 fiance. 
 
61 
 
 ELEMENTS 
 
 ftance, by the term of oxygenation : from which 
 I fhall adopt the verb to oxygenate , and, of con- 
 fequence fhall fay, that in oxygenating phofpho- 
 xus we convert it into an acid. 
 
 Sulphur is likewife a combuftible body, or, in 
 other words, it is a body which poffeffes the 
 power of decompofing oxygen gas, by attract- 
 ing the oxygen from the caloric with which it 
 was combined. This can very eafily be proved, 
 by means of experiments quite fimilar to thofe 
 we have given with phofphorus ; but it is ne- 
 ceffary to premife, that in thefe operations with 
 fulphur, the fame accuracy of refult is not to 
 be expeCted as with phofphorus ; becaufe the 
 acid which is formed by the combuftion of ful- 
 phur is difficultly condenfible, and becaufe ful- 
 phur burns with more difficulty, and is foluble 
 in the different gaffes. But I can fafely affert, 
 from my own experiments, that fulphur in 
 burning abforbs oxygen gas ; that the refulting 
 acid is confiderably heavier than the fulphur 
 burnt ; that its weight is equal to the fum of 
 the weights of the fulphur which has been 
 burnt, and of the oxygen abforbed ; and, laflly, 
 that this acid is weighty, incombuftible, and 
 mifcible with water in all proportions : The only 
 uncertainty remaining upon this head, is with 
 regard to the proportions of fulphur and of 
 oxygen which enter into the compofition of the 
 acid. 
 
 Charcoal, 
 
OF CHEMISTRY. ^ 
 
 Charcoal, which, from all our prefent know- 
 ledge regarding it, mud be confidered as a fim- 
 ple combudible body, has likevvife the property 
 of decompofing oxygen gas, by abforbing its 
 bafe from the caloric : But the acid refulting 
 from this combudion does not condenfe in the 
 common temperature ; under the preffure of 
 our atmofphere, it remains in the date of gas, 
 and requires a large proportion of water to 
 combine with or be diffolved in. This acid 
 has, however, all the known properties of other 
 acids, though in a weaker degree, and com- 
 bines, like them, with all the bafes which are fuf- 
 ceptible of forming neutral falts. 
 
 The combudion of charcoal in oxygen gas, 
 may be effected like that of phofphorus in the 
 bell-giafs, (A. PI. IV. fig. 3.) placed ever mer- 
 cury : but, as the heat of red hot iron is not 
 fufficient to fet fire to the charcoal, we mud 
 add a fmall morfel of tinder, with a mi- 
 nute particle of phofphorus, in the fame manner 
 as directed in the experiment for the combuf- 
 tion of iron. A detailed account of this ex- 
 periment will be found in the memoirs of the 
 academy for 1781, p. 448. By that experi- 
 ment it appears, that 28 parts by weight of 
 charcoal require 72 parts of oxygen for fatura- 
 tion, and that the aeriform acid produced is 
 precifely equal in weight to the fum of the 
 xveights of the charcoal and oxygen gas em- 
 ployed, 
 
ELEMENTS 
 
 ployed. This aeriform acid was called fixed 
 or fixable air by the chemifts who firft difcover- 
 ed it y they did not then know whether it was 
 air refembling that of the atmofphere, or fome 
 other elaftic fluid, vitiated and corrupted by com- 
 buftion ; but fince it is now afcertained to be 
 an acid, formed like all others by the oxygena- 
 tion of its peculiar bafe, it is obvious that the 
 name of fixed air is quite ineligible*. 
 
 By burning charcoal in the apparatus men- 
 tioned p. 60, Mr de la Place and I found that 
 one lib . of charcoal melted 96 libs. 6 oz. of 
 ice ; that, during the combuftion, 2 libs . 9 oz. 
 1 gros . 10 grs. of oxygen were abforbed, and 
 that 3 libs . 9 oz. 1 gros . 10 grs. of acid gas 
 were formed. This gas weighs 0.695 P art s 
 of a grain for each cubical inch, in the com- 
 mon ftandard temperature and preflure men- 
 tioned above, fo that 34,242 cubical inches of 
 acid gas are produced by the combuftion of one 
 pound of charcoal. 
 
 1 might multiply thefe experiments, and ftiow 
 by a numerous fucceflion of fa&s, that all acids 
 are formed by the combuftion of certain fub- 
 ftances ; but I am prevented from doing fo in 
 
 this 
 
 * It may be proper to remark, though here omit- 
 ted by the author, that, in conformity with the general 
 principles of the new nomenclature, this acid is by Mr 
 Lavoifier and his coleagues called the carbonic acid, 
 and when in the aeriform ftate carbonic acid gas. E. 
 
0 F CHEMISTRY, 6$ 
 
 place, by the plan which I have laid down, of 
 proceeding only from fafts already afcertained, 
 to fuch as are unknown, and of drawing my 
 examples only from circumflances already ex- 
 plained. In the mean time, however, the three 
 examples above cited may fuffice for giving & 
 cleat and accurate conception of the manner in 
 which acids are formed. By thefe it may be 
 clearly feen, that oxygen is an element common 
 to them all, which conftitutes their acidity; 
 and that they differ from each other, according 
 to the nature of the oxygenated or acidified 
 fubftance. We muff therefore, in every acid* 
 carefully diftinguifh between the acidifiable, 
 bafe, which Mr de Morveau calls the radical* 
 and the acidifiing principle or oxygen. 
 
 t 
 
 CHAP, 
 
66 
 
 ELEMENTS 
 
 C H A P. VI. 
 
 Of the Nomenclature of Acids in general , and parti* 
 cularly of thofe drawn from Nitre and Sea- Salt* 
 
 TT becomes extremely eafy, from the prin- 
 -*■ ciples laid down in the preceding chapter* 
 to eftablifh a fyftematic nomenclature for the a- 
 cids: The word acid : being ufed as a generic term* 
 each acid falls to be diftinguifhed in language, as 
 in nature, by the name of its bafe or radical. 
 Thus, we give the generic name of acids to the 
 produ&s of the combuftion or oxygenation of 
 phofphorus, of fulphur, and of charcoal ; and 
 thefe produdls are refpectively named, the phof 
 phoric acid , the fulphur it acid and the carbonic 
 acid . 
 
 There is, however, a remarkable circumftance 
 in the oxygenation of combuftible bodies, and 
 of a part of fuch bodies as are convertible in- 
 to acids, that they are fufceptible of different 
 degrees of faturation with oxygen, and that the 
 refulting acids, though formed by the union of 
 the fame elements, are poffeffed of different pro* 
 perties, depending upon that difference of pro- 
 portion. Of this, the phofphoric acid, and more 
 efpecially the fulphuric, furnifhes us with ex- 
 amples. 
 
OF CHEMISTRY. % 
 
 amples. When fulphur is combined with a 
 finall proportion of oxygen, it forms, in this 
 firft or lower degree of oxygenation, a volatile 
 acid, having a penetrating odour, and poffefled 
 of very particular qualities. By a larger pro- 
 portion of oxygen, it is changed into a fixed, 
 heavy acid, without any odour, and which, by 
 combination with other bodies, gives products 
 quite different from thofe furnifhed by the for- 
 mer. In this inftance, the principles of our no- 
 menclature feetn to fail ; and it feems difficult 
 to derive fuch terms from the name of the acidi- 
 fiable bafe, as fhall diflin&ly exprefs thefe two 
 degrees of faturation, or oxygenation, without 
 circumlocution. By reflection, however, upon 
 the fubjed, or perhaps rather from the neceflity 
 of the cafe, we have thought it allowable to ex- 
 prefs thefe varieties in the oxygenation of the 
 acids, by limply varying the termination of their 
 fpecific names. The volatile acid produced 
 from fulphur was anciently known to Stahl un- 
 der the name of fulphurous acid *. We have 
 
 pre- 
 
 * The term formerly ufed by the Englifh chemifts 
 for this acid was written fulphureous ; but we have 
 thought proper to fpell it as above, that it may better 
 conform with the fimilar terminations of nitrous, car- 
 bonous, &c. to be ufed hereafter. In general, we 
 have ufed the Englifh terminations ic and ous to tran- 
 slate the terms of the Author which end with iqne and 
 £»x,with hardly any other alterations.— E, 
 
ELEMENTS 
 
 tit 
 
 preferved that term for this acid from fulphur un* 
 der-faturated with oxygen ; and diftinguifh the 
 other, or completely faturated or oxygenated a- 
 cid, by the name of fulphur ic acid. We fhall 
 therefore fay', in this new chemical language, 
 that fulphur, in combining with oxygen, is fu- 
 fceptible of two degrees of faturation ; that the 
 firft, or leffer degree, conflitutes fulphurous a- 
 cid, which is volatile and penetrating ; whilft 
 the fecond, or higher degree of faturation, pro- 
 duces fulphuric acid, which is fixed and inodo- 
 rous. We fliall adopt this difference of termi- 
 nation for all the acids which affume feveral de- 
 grees of faturation. Lienee we have a phof- 
 phqrous and a phofphoric acid, an acetous and 
 an acetic acid ; and fo on, for others in fimilat 
 circumftances. 
 
 This part of chemical fcience would have 
 been extremely fimple, and the nomenclature 
 of the acids would not have been at all per- 
 plexed, as it is now in the old nomenclature, if 
 the bale or radical of each acid h^d been known 
 when the acid itfelf was difcovered. Thus, for 
 inftance, phofphorus being a known fubftange 
 before the difcovery of its acid, this latter was 
 rightly diflinguifhed by a term drawn from the 
 name of its acidifiable bafe. But when, on the 
 contrary, an acid happened to be difcovered be- 
 fore its bafe, or rather, when the acidifiable bafe 
 from which it was formed remained unknown, 
 
 names 
 
OF CHEMISTRY* 
 
 names were adopted for the two, which have 
 not the fmalleft connection ; and thus, not only 
 the memory became burthened with ufelefs ap- 
 pellations, but even the minds of ftudents, nay 
 even of experienced chemifts, became filled 
 with falfe ideas, which time and reflection alone 
 is capable of eradicating. We may give an in- 
 ftance of this confufion with refpeCt to the acid 
 fulphur : The former chemifts having procured 
 this acid from the vitriol of iron, gave it the 
 name of the vitriolic acid from the name of the 
 fubftance w r hich produced it ; and they were 
 then ignorant that the acid procured from ful- 
 phur by combuftion was exactly the fame. 
 
 The fame thing happened with the aeri- 
 form acid formerly called fixed air ; it not 
 being known that this acid was the refult of 
 combining charcoal with oxygen, a variety of 
 denominations have been given to it, not one 
 of which conveys juft ideas of its nature or ori- 
 gin. We have found it extremely eafy to cor- 
 rect and modify the ancient language with re- 
 fpeCt to thefe acids proceeding from known 
 bafes, having converted the name of vitriolic a- 
 cid into that of fulphuric , and the name of fixed 
 air into that of carbonic acid ; but it is impof- 
 fible to follow this plan with the acids whofe ba- 
 fes are (till unknown ; with thefe we have been 
 obliged to ufe a contrary plan, and, inftead of 
 forming the name of the acid from that of its 
 
 bafe ? 
 
70 
 
 ELEMENTS 
 
 bafe, have been forced to denominate the un- 
 known bafe from the name of the known acid, 
 as happens in the cafe of the acid which is pro- 
 cured from fea*falt. 
 
 To difengage this acid from the alkaline bafe 
 with which it is combined, we have only to 
 pour fulphuric acid upon fea-falt, immediately 
 a brifk effervefcence takes place, white vapours 
 arife, of a very penetrating odour, and, by on- 
 ly gently heating the mixture, all the acid is 
 driven off. As, in the common temperature 
 and preffure of our atmofphere, this acid is na- 
 turally in the (late of gas, we mud ufe particu- 
 lar precautions for retaining it in proper veffels. 
 For final! experiments, the mod fimple and 
 mod commodious apparatus confids of a fmall 
 retort G, (PL V. Fig, 5.), into which the fea- 
 falt is introduced, well dried *, we then pour 
 on fome concentrated fulphuric acid, and im- 
 mediately introduce the beak of the retort under 
 little jars or bell-glaffes A, (fame Plate and Fig.), 
 previoufly filled with quickfilver. In propor- 
 tion as the acid gas is difengaged, it palfes into 
 the jar, and gets to the top of the quickfilver, 
 which it difplaces. When the difengagement 
 
 of 
 
 * For this purpofe, the operation called decrepitation 
 is ufed, which confids in fubjeeting it to nearly a red 
 heat, in a proper veflel, fo as to evaporate all its water 
 of cryftallization,— - F. 
 
OF CHEMISTRY. ft 
 
 of the gas flackens, a gentle heat is applied 
 to the retort, and gradually increafed till no- 
 thing more paffes over. This acid gas has a 
 very (Irong affinity with water, which abforbs 
 an enormous quantity of it, as is proved by in- 
 troducing a very thin layer of water into the 
 glafs which contains the gas ; for, in an inftant, 
 the whole acid gas difappears, and combines 
 with the water. 
 
 This latter circumftance is taken advantage 
 of in laboratories and manufactures, on purpofe 
 to obtain the acid of fea-falt in a liquid form j 
 and for this purpofe the apparatus (PI. lV a 
 Fig. i.) is employed. It confifts, ift, of a tu- 
 bulated retort A, into which the fea-falt, and af- 
 ter it the fulphurie acid, are introduced through 
 the opening H ; 2d, of the baloon or recipient 
 by intended for containing the fmall quantity 
 of liquid which paffies over during the procefs 5 
 and, 3d, of a fet of bottles, with two mouths, 
 L, L,L, L, half filled with water, intended for 
 abforbing the gas difengaged by the diftilla- 
 tion. This apparatus will be more amply de- 
 fcribed in the latter part of this work. 
 
 Although we have not yet been able, either 
 to compofe or to decompound this acid of fea- 
 fait, we cannot have the fmaUeft doubt that it, 
 like all other acids, is compofed by the union 
 of oxygen with an acidifiable bafe. We have 
 therefore called this unknown fubffance the 
 
 muriatic 
 
ELEMENTS 
 
 7 * • 
 
 muriatic bafe, or muriatic radical , deriving this 
 name, after the example of Mr Bergman and 
 Mr de Morveau, from the Latin word muria , 
 which was anciently ufed to figniiy fea-falt. 
 Thus, without being able exa&ly to determine 
 the component parts of muriatic acid y we defign, 
 by that term, a volatile acid, which retains the 
 form of gas in the common temperature and 
 preffure of our atmofphere, which combines 
 with great facility, and in great quantity, with 
 water, and whofe acidifiable bafe adheres fo ve- 
 ry intimately with oxygen, that no method has 
 hitherto been devifed for feparating them. If 
 ever this acidifiable bafe of the muriatic acid is 
 difcovered to be a known fubftance, though 
 now unknown in that capacity, it will be requi- 
 fite to change its prefent denomination for one 
 analogous with that of its bafe. 
 
 In common with fulphuric acid, and feveral 
 other acids, -the muriatic is capable of different 
 degrees of oxygenation ; but the excefs of oxy- 
 gen produces quite contrary effe&s upon it from 
 what the fame circumftance produces upon the 
 acid of fulphur. The lower degree of oxyge- 
 nation converts fulphur into a volatile gaffeous 
 acid, which only mixes in fmall proportions with 
 water, whilfl a higher oxygenation forms an a- 
 cidpoffeffingmuchftronger acid properties, which 
 is very fixed and cannot remain in the flate of 
 gas but in a very high temperature, which has 
 
 no 
 
73 
 
 OF CHEMISTRY, 
 
 no fmell, and which mixes in large propor- 
 tion with water. With muriatic acid, the di- 
 red: reverfe takes place ; an additional fatura- 
 tion with oxygen renders it more volatile, of 
 a more penetrating odour, lefs mifcible with 
 water, and diminiihes its acid properties. We 
 were at firft inclined to have denominated thefe 
 two degrees of faturation in the fame manner 
 as we had done with the acid of fulphur, calling 
 the lefs oxygenated muriatous acid , and that 
 which is more faturated with oxygen muriatic 
 acid : But, as this latter gives very particular 
 refults in its combinations, and as nothing ana- 
 logous to it is yet known in chemiftry, we have 
 left the name of muriatic acid to the lefs fatu- 
 rated, and give the latter the more compounded 
 appellation of oxygenated muriatic acid. 
 
 Although the bafe or radical of the acid 
 which is extraded from nitre or faltpetre be 
 better known, we have judged proper only 
 to modify its name in the fame manner 
 with that of the muriatic acid. It is drawn 
 from nitre, by the intervention of fulphuric 
 acid, by a procefs fimilar to that defcribed 
 for extrading the muriatic acid, and by means 
 of the fame apparatus (PL IV. Fig. i.). In 
 proportion as the acid paffes over, it is in part 
 condenfed in the baloon or recipient, and the 
 reft is abforbed by the water contained in the 
 bottles L, L, L, L - } the water becomes firft green, 
 K then 
 
74 
 
 ELEMENTS 
 
 then blue, and at laft yellow, in proportion to 
 the concentration of the acid. During this ope- 
 ration, a large quantity of oxygen gas, mixed 
 with a fmall proportion of azotic gas, is difen- 
 gaged. 
 
 This acid, like all others, is compofed of oxy- 
 gen, united to an acidifiable bafe, and is even 
 the firfl: acid in which the exigence of oxygen 
 was well afcertained. Its two conflituent ele- 
 ments are but weakly united, and are eafily fe- 
 parated, by prefenting any fubftance with which 
 oxygen has a ftronger affinity than with the aci- 
 difiable bafe peculiar to this acid. By fome ex- 
 periments of this kind, it was firfl: difcovered 
 that azote, or the bafe of mephitis or azotic gas, 
 conftituted its acidifiable bafe or radical ; and 
 confequently that the acid of nitre was really an 
 azotic acid, having azote for its bafe, combined 
 with oxygen. For thefe reafons, that we might 
 be confident with our principles, it appeared 
 neceflary, either to call the acid by the name of 
 azotic, or to name the bafe nitric radical ; but 
 from either of thefe we were difluaded, by the 
 following confiderations. In the firjl place, it 
 feemed difficult to change the name of nitre or 
 faltpetre, which has been univerfally adopted 
 in fociety, in manufactures, and in chemiflry ; 
 and, on the other hand, azote having been dif- 
 covered by Mr Berthollet to be the bafe of vo- 
 latile alkali, or ammoniac, as well as of this a- 
 
 cid. 
 
OF CHEMISTRY, 
 
 75 
 
 cid, we thought it improper to call it nitric ra- 
 dical. We have therefore continued the term 
 of azote to the bafe of that part of atmofpheric 
 air which is likewife the nitric and ammoniacal 
 radical ; and we have named the acid of nitre, 
 in its lower and higher degrees of oxygenation, 
 nitrous acid in the former, and nitric acid in the 
 latter date ; thus preferving its former appella- 
 tion properly modified. 
 
 Several very refpedable chemids have difap- 
 proved of this deference for the old terms, and 
 wifhed us to have perfevered in perfeding a 
 new chemical language, without paying any re- 
 fped for ancient ufage \ fo that, by thus fleer- 
 ing a kind of middle courfe, we have expofed 
 ourfelves to the cenfures of one fed of chemifls, 
 and to the expoflulations of the oppofite party. 
 
 The acid of nitre is fufceptible of affuming a 
 great number of feparate dates, depending up- 
 on its degree of oxygenation, or upon the pro- 
 portions in which azote and oxygen enter into 
 its compofiticn. By a fird or lowed degree of 
 oxygenation, it forms a particular fpecies of 
 gas, which we {hail continue to name nitrous 
 gas ; this is compofed nearly of two parts, by 
 weight, of oxygen combined with one part of 
 azote ; and in this date it is not mifcible with 
 water. In this gas, the azote is by no means 
 faturated with oxygen, but, on the contrary, has 
 
 dill 
 
7 s 
 
 ELEMENTS 
 
 Hill a very great affinity for that element, and 
 even attra&s it from atmofpheric air, immedi- 
 ately upon getting into contact with it. This 
 combination of nitrous gas with atmofpheric air 
 has even become one of the methods for deter- 
 mining the quantity of oxygen contained in air, 
 and confequently for afcertaining its degree of 
 falubrity. 
 
 This addition of oxygen converts the nitrous 
 gas into a powerful acid, which has a ftrong af- 
 finity with water, and which is itfelf fufceptible 
 of various additional degrees of oxygenation. 
 When the proportions of oxygen and azote is 
 below three parts, by weight, of the former, to 
 one of the latter, the acid is red coloured, and 
 emits copious fumes. In this ftate, by the ap- 
 plication of a gentle heat, it gives out nitrous 
 gas ; and we term it, in this degree of oxyge- 
 nation, nitrous acid . When four parts, by 
 weight, of oxygen, are combined with one part 
 of azote, the acid is clear and colourlefs, more 
 fixed in the fire than the nitrous acid, has lefs 
 odour, and its conftituent elements are more 
 firmly united. This fpecies of acid, in confor- 
 mity with our principles of nomenclature, is 
 called nitric acid. 
 
 Thus, nitric acid is the acid of nitre, fur- 
 charged with oxygen ; nitrous acid is the acid 
 of nitre furcharged with azote ; or, what is the 
 fame thing, with nitrous gas \ and this latter is 
 
 azote 
 
OF CHEMISTRY. 
 
 77 
 
 azote not fufficiently faturated with oxygen to 
 poflefs the properties of an acid. To this de- 
 gree of oxygenation, we have afterwards, in the 
 courfe of this work, given the generical name 
 of oxyd *. 
 
 CHAP. 
 
 * In ftri& conformity with the principles of the new 
 nomenclature, but which the Author has given his rea» 
 fons for deviating from in this inftance, the following 
 ought to have been the terms for azote, in its feveral 
 degrees of oxygenation : Azote, azotic gas, (azote 
 !; combined with caloric), azotic oxyd gas, nitrous acid, 
 
 ; and nitric acid. — E. 
 
;3 
 
 ELEMENTS 
 
 CHAP. VII. 
 
 ' 
 
 Of the Decompofition of Oxygen Gas by means of 
 Metals , and the Formation of Metallic Oxyds. 
 
 XYGEN has a ftronger affinity with me- 
 
 tals heated to a certain degree than with 
 caloric ; in confequence of which, all metallic 
 bodies, excepting gold, filver, and platina, have 
 the property of decompofing oxygen gas, by at- 
 tracting its bafe from the caloric with which it 
 was combined. We have already fhown in 
 what manner this decompofition takes place, by 
 means of mercury and iron ; having obferved, 
 that, in the cafe of the firft, it muft be confi- 
 dered as a kind of gradual combuftion, whilft, 
 in the latter, the combuftion is extremely rapid, 
 and attended with a brilliant flame. The ufe 
 of the heat employed in thefe operations is to 
 feparate the particles of the metal from each 
 other, and to diminifh their attraction of cohe 
 fion or aggregation, or, what is the fame thing 
 their mutual attraction for each other. 
 
 The abfolute weight of metallic fubftances ii 
 augmented in proportion to the quantity o 
 oxygen they abforb ; they, at the fame time, lof< 
 their metallic fplendour, and are reduced into 
 
 an 
 
 
OF CHEMISTRY. 
 
 79 
 
 an earthy pulverulent matter. In this (late me- 
 tals mull not be confidered as entirely faturated 
 with oxygen, becaufe their action upon this ele- 
 ment is counterbalanced by the power of affinity 
 between it and caloric. During the calcination 
 of metals, the oxygen is therefore a£ted upon 
 by two feparate and oppofite powers, that of its 
 attraction for caloric, and that exerted by the 
 metal, and only tends to unite with the latter in 
 confequence of the excefs of the latter over the 
 former, which is, in general, very inconfider- 
 able. Wherefore, when metallic fubftances are 
 oxygenated in atmofpheric air, or in oxygen 
 gas, they are not converted into acids like ful- 
 phur, phofphorus, and charcoal, but are only 
 changed into intermediate fubftances, which, 
 though approaching to the nature of falts, have 
 not acquired all the laline properties. The old 
 chemifts have affixed the name of calx not only 
 to metals in this ftate, but to every body which 
 has been long expofed to the a&ion of fire with- 
 out being melted. They have converted this 
 word calx into a generical term, under which 
 they confound calcareous earth, which, from a 
 neutral fait, which it really was before calcina- 
 tion, has been changed by fire into an earthy 
 alkali, by loftng half of its weight, with metals 
 which, by the fame means, have joined them* 
 felves to a new fubftance, whofe quantity often 
 exceeds half their weight, and by which they 
 
 have 
 
ELEMENTS 
 
 $0 
 
 have been changed almoft into the nature of 
 acids. This mode of claflifying fubftances of 
 fo very oppofite natures, under the fame gene- 
 ric name, would have been quite contrary to 
 our principles of nomenclature, efpecially as, 
 by retaining the above term for this hate of 
 metallic fubftances, we muft have conveyed very 
 falfe ideas of its nature. We have, therefore, 
 laid afide the expreflion metallic calx altogether, 
 and have fubftituted in its place the term oxyd 9 
 from the Greek word 
 
 By this may be feen, that the language we 
 have adopted is both copious and expreffive. 
 The firft or loweft degree of oxygenation in 
 bodies, converts them into oxyds ; a fecond de- 
 gree of additional oxygenation conftitutes the 
 clafs of acids, of which the fpecific names, 
 drawn from their particular bafes, terminate in 
 ous, as the nitrous and fulphurous acids ; the third 
 degree of oxygenation changes thefe into the 
 fpecies of acids diftinguifhed by the termination 
 in ic 9 as the nitric and fulphuric acids ; and, laft- 
 ly, we can exprefs a fourth, or higheft degree 
 of oxygenation, by adding the word oxygenated 
 to the name of the acid, as has been already 
 done with the oxygenated muriatic acid. 
 
 We have not confined the term oxyd to ex- 
 prefling the combinations of metals with oxy- 
 gen, but have extended it to fignify that firft 
 degree of oxygenation in all bodies, which, 
 
 without 
 
OF CHEMISTRY. 
 
 it 
 
 without converting them into acids, caufes them 
 to approach to the nature of falts. Thus, we give 
 the name of oxyd of fulphur to that foft fubftance 
 into which fulphur is converted by incipient 
 combuftion ; and we call the yellow matter left 
 by phofphorus, after combuftion, by the name 
 of oxyd of phofphorus . In the fame manner, ni- 
 trous gas, which is azote in its firft degree of 
 oxygenation, is the oxyd of azote. We have like- 
 wife oxyds in great numbers from the vegetable 
 and animal kingdoms ; and I ftiall fhow, in the 
 fequel, that this new language throws great 
 light upon all the operations of art and nature. 
 
 We have already obferved, that almoft all 
 the metallic oxyds have peculiar and permanent 
 colours. Thefe vary not only in the different 
 fpecies of metals, but even according to the va- 
 rious degrees of oxygenation in the fame metal. 
 Hence we are under the necefiity of adding two 
 epithets to each oxyd, one of which indicates 
 the metal oxydated *, while the other indicates 
 L the 
 
 * Here we fee the word oxyd converted into the 
 verb to oxydate , oxydated , oxy datings after the fame man- 
 ner with the derivation of the verb to oxygenate , oxygena - 
 ted, oxygenating , from the word oxygen . I am not clear 
 of the abfolute neceflity of this l'econd verb here firft 
 introduced, but think, in a work of this nature, that it 
 is the duty of the tranflator to neglect every other con- 
 fideration for the fake of ftrict fidelity to the ideas of 
 his author.— E. 
 
t 
 
 Bi ELEMENTS 
 
 the peculiar colour of the oxyd. Thus, we 
 have the black oxyd of iron, the red oxyd of 
 iron, ar»d the yellow oxyd of iron ; which ex- 
 p> offiojis refpe&iveiy anfwer to the old unmean- 
 ing erms of martial ethiops, colcothar, and ruft 
 of iron, or ochre. We have likewife the gray, 
 yellow, and red oxyds of lead, which anfwer to 
 U equally falfe or infignificant terms, afhes of 
 lead, rnafficot, and minium. 
 
 Thefe denominations fometimes become ra- 
 ther long, efpecially when we mean to indicate 
 whether the metal has been oxydated in the 
 air, by detonation with nitre, or by means of 
 acids ; but then they always convey juft and 
 accurate ideas of the correfponding object which 
 we wifli to exprefs by their ufe. All this will 
 be rendered perfectly clear and diftinft by mean§ 
 of the tables which are added to this work. 
 
 C H A l\ 
 
OF CHEMISTRY. * 3 
 
 ;:v 
 
 CHAP. VIII. 
 
 1 ’ 
 
 Of the Radical Principle of Water , and of its De* 
 
 , compofition by Charcoal and Iron . 
 
 U NTIL very lately, water has always been 
 thought a fimple fubftance, infomuch 
 that the older chemifts confidered it as an ele- 
 ment. Such it undoubtedly was to them, as 
 they were unable to decompofe it ; or, at leaf!:, 
 fince the decompofition which took place daily 
 before their eyes was entirely unnoticed. But 
 we mean to prove, that water is by no means a 
 fimple or elementary fubftance. I fliall not here 
 pretend to give the hiftory of this recent, and 
 hitherto contefted difcovery, which is detailed 
 in the Memoirs of the Academy for 1781, but 
 ftiali only bring forwards the principal proofs of 
 the decompofition and compofition of water ; 
 and, I may venture to fay, that thefe will be 
 convincing to fuch as confider them impartially. 
 
 Experiment Firft . 
 
 Having fixed the glafs tube EF, (PL vii. fig. 
 31.) of from 8 to 12 lines diameter, acrofs a 
 furnace, with a fmall inclination from E to F, 
 
 lute 
 

 ELEMENTS 
 
 lute the fuperior extremity E to the glafs retort 
 A, containing a determinate quantity of diftilled 
 water, and to the inferior extremity F, the 
 worm SS fixed into the neck of the doubly tu- 
 bulated bottle H, which has the bent tube KK 
 adapted to one of its openings, in fuch a man- 
 ner as to convey fuch aeriform fluids or gaffes 
 as may be difengaged, during the experiment, 
 into a proper apparatus for determining their 
 quantity and nature. 
 
 To render the fuccefs of this experiment cer- 
 tain, it is neceffary that the tube EF be made of 
 well annealed and difficultly fufible glafs, and 
 that it be coated with a lute compofed of clay 
 mixed with powdered ftone*ware; befides which, 
 it muff be fupported about its middle by means 
 of an iron bar paffed through the furnace, left 
 it fhould foften and bend during the experiment. 
 A tube of China-ware, or porcellain, would an- 
 iwer better than one of glafs for this experi- 
 ment, were it not difficult to procure one fo en- 
 tirely free from pores as to prevent the paffage 
 of air or of vapours. 
 
 When things are thus arranged, a fire is light- 
 ed in the furnace EFCD, which is fupported of 
 fuch a ftrength as to keep the tube EF red hot, 
 but not to make it melt ; and, at the fame time, 
 fuch a fire is kept up in the furnace VVXX, as 
 to keep the water in the retort A continually 
 boiling. 
 
 In 
 
OF CHEMISTRY, 
 
 In proportion as the water in the retort A is 
 evaporated, it fills the tube EF, and drives out 
 the air it contained by the tube KK ; the aque- 
 ous gas formed by evaporation is condenfed by 
 cooling in the worm SS, and falls, drop by drop., 
 into the tubulated bottle H. Having continued 
 this operation until all the water be evapora- 
 ted from the retort, and having carefully emp- 
 tied all the velfels employed, we find that a 
 quantity of water has pafled over into the bot- 
 tle H, exa&ly equal to what was before contain- 
 ed in the retort A, without any difengagement 
 of gas whatfoever : So that this experiment 
 turns out to be a fimple diftillation $ and the re- 
 fult would have been exadly the fame, if the 
 water had been run from one vefiel into the 
 other, through the tube EF, without having un- 
 dergone the intermediate incandefcence. 
 
 Experiment Second . 
 
 The apparatus being difpofed, as in the for- 
 mer experiment, 28 grs. of charcoal, broken in- 
 to moderately fmall parts, and which has pre- 
 vioufly been expofed for a long time to a red 
 heat in clofe veffels, are introduced into the tube 
 EF. Every thing elfe is managed as in the pre- 
 ceding experiment. 
 
 The water contained in the retort A is didd- 
 led, as in the former experiment, and, being 
 
 condenfed 
 
8 6 ELEMENTS 
 
 condenfed in the worm, falls into the bottle 
 but, at the fame time, a confiderable quantity 
 of gas is difengaged, which, efcaping by the tube 
 KK, is received in a convenient apparatus for 
 that purpofe. After the operation is finifhed, 
 we find nothing but a few atoms of afhes re- 
 maining in the tube EF ; the 28 grs. of charcoal 
 having entirely difappeared. 
 
 When the difengaged gaffes are carefully ex- 
 amined, they are found to weigh 1 13.7 grs. * 5 
 thefe are of two kinds, viz. 144 cubical inches 
 of carbonic acid gas, weighing loogrr. and 380 
 cubical inches of a very light gas, weighing on- 
 ly 13*7 grs, which takes fire when in contaft 
 with air, by the approach of a lighted body; 
 and, when the water which has paffed over into 
 the bottle H is carefully examined, it is found 
 to have loft 85.7 grs. of its weight. Thus, in 
 this experiment, 85.7 grs. of water, joined to 28 
 grs. of charcoal, have combined in fuch a way 
 as to form ioogrr. of carbonic acid, and 13.7 
 grs. of a particular gas capable of being burnt. 
 
 I have already fhown, that 1 00 grs. of carbo* 
 nic acid gas confifts of 72 grs. of oxygen, com- 
 bined with 28 grs. of charcoal; hence the 28 
 
 grs. 
 
 * In the latter part of this work will be found a 
 particular account of the proceffes neceffary for fepa- 
 rating the different kinds of gaffes, and for determin- 
 ing their quantities.— ■ A. 
 
OF CHEMISTRY. 87 
 
 grs. of charcoal placed in the glafs tube have 
 acquired 72 grs. of oxygen from the water; and 
 it follows, that 85.7 grs. of water are compofed 
 of 72 grs. of oxygen, combined with 13.7 grs . 
 of a gas fufceptible of combuftion. We Ihali 
 fee prefently that this gas cannot poflibly have 
 been difengaged from the charcoal, and mud, 
 confequentlv, have been produced from the wa- 
 ter. 
 
 I have fupprefied fome circumftances in the 
 above account of this experiment, which would 
 only have complicated and obfcured its refults 
 in the minds of the reader. For inftance, the 
 inflammable gas diflolves a very fmall part of 
 the charcoal, by which means its weight is fome- 
 what augmented, and that of the carbonic gas 
 proportionally diminiftied. Altho’ the alteration 
 produced by this circumftance is very inconfide- 
 rable ; yet I have thought it neceflary to deter- 
 mine its effects by rigid calculation, and to re- 
 port, as above, the refults of the experiment in 
 its Amplified date, as if this circumftance had 
 not happened. At any rate, ihould any doubts 
 remain refpe&ing the confequences I have drawn 
 from this experiment, they will be fully difii- 
 pated by the following experiments, which I am 
 going to adduce in fupport of my opinion. 
 
 Experiment 
 
ELEMENTS 
 
 3$ 
 
 
 Experiment Third. 
 
 The apparatus being difpofed exa&ly as in 
 the former experiment, with this difference, that 
 inftead of the 28 grs. of charcoal, the tube EF 
 is filled with 274 grs . of foft iron in thin plates, 
 rolled up fpirally. The tube is made red hot 
 by means of its furnace, and the water in the 
 retort A is kept conftantiy boiling till it be all 
 evaporated, and has palled through the tube EF, 
 fo as to be condenfed in the bottle H. 
 
 No carbonic acid gas is difengaged in this ex- 
 periment, inftead of which we obtain 416 cubi- 
 cal inches, or 15 grs . of inflammable gas, thir- 
 teen times lighter than atmofpheric air. By 
 examining the water which has been diftilled, 
 it is found to have loft 1 00 grj. and the 274 
 grs. of iron confined in the tube are found to 
 have acquired 85 grs. additional weight, and its 
 magnitude is confiderably augmented. The iron 
 is now hardly at all attra&able by the magnet ; 
 it diffolves in acids without effervefcence ; and, 
 in fhcrt, it is converted into a black oxyd, pre- 
 cifely fimilar to that which has been burnt in 
 oxygen gas. 
 
 In this experiment we have a true oxydation 
 of iron, by means of water, exactly fimilar to 
 that produced in air by the afliftance of heat. 
 One hundred grains of water having been de- 
 
 compofed. 
 
OF CHEMISTRY. 
 
 compofed, 85 grs. of oxygen have combined 
 with the iron, fo as to convert it into the (late 
 of black oxyd, and 15 grs. of a peculiar inflam- 
 mable gas are difengaged : From all this it clear- 
 ly follows, that water is compofed of oxygen 
 combined with the bafe of an inflammable gas, 
 in the refpe&ive proportions of 85 parts, by 
 weight of the former, to 15 parts of the latter. 
 
 Thus water, befides the oxygen, which is one 
 of its elements in common with Vnany other 
 fubftances, contains another element as its con- 
 ftituent bafe or radical, and for which we muft 
 find an appropriate term. None that we could 
 think of feemed better adapted than the word 
 hydrogen , which dignifies the generative principle 
 of vjater , from vS'oj) aqua , and yunpxt gignor *. 
 We call the combination of this element with 
 caloric hydrogen gas ; and the term hydrogen 
 expreffes the bafe of that gas, or the radical of 
 water. 
 
 M This 
 
 * This expreffion Hydrogen has been very feverely 
 criticifed by fome, who pretend that it fignifies engen- 
 dered by water, and not that which engenders water. 
 
 The experiments related in this chapter prove, that, 
 when water is decompofed, hydrogen is produced, 
 and that, when hydrogen is combined with oxygen, 
 water is produced : So that we may fay, with equal 
 truth, that water is produced from hydrogen, or hy- 
 drogen is produced from water. — A. < 
 
ELEMENTS 
 
 9 ° 
 
 This experiment furniffies us with a new conw 
 buftible body, or, in other words, a body which 
 has fo much affinity with oxygen as to draw it 
 from its connection with caloric, and to decom- 
 pofe air or oxygen gas. This combuftible bo- 
 dy has itfelf fo great affinity with caloric, that, 
 unlefs when engaged in a combination with 
 fome other body, it always fubfifts in the aeri- 
 form or gaffeous ftate, in the ufual temperature 
 and preffure of our atmofphere. In this ftate of 
 gas it is about -A- of the weight of an equal 
 bulk of atmofpheric air ; it is not abforbed by 
 water, though it is capable of holding a fmall 
 quantity of that fluid in folution, and it i§ in- 
 capable of being ufed for refpiration. 
 
 As the property this gas poffeffes, in com- 
 mon with all other combuftible bodies, is no- 
 thing more than the power of decompofing air, 
 and carrying off its oxygen from the caloric 
 with which it was combined, it is eafily under- 
 ftood that it cannot burn, unlefs in contact with 
 air or oxygen gas. Hence, when we fet fire to 
 a bottle full of this gas, it burns gently, firft at 
 the neck of the bottle, and then in the infide of 
 it, in proportion as the external air gets in : 
 This combuftion is flow and facceffive, and on- 
 ly takes place at the furface of contact between 
 the two gaffes. It is quite different when the two 
 gaffes are mixed before they are fet on fire : If, 
 for inftance, after having introduced one part of 
 
 oxygen 
 
OF CHEMISTRY. 
 
 oxygen gas into a narrow mouthed bottle, we 
 fill it up with two parts of hydrogen gas, and 
 bring a lighted taper, or other burning body, 
 to the mouth of the bottle, the combuftion of 
 the two gaffes takes place inflantaneoufly with 
 a violent explofion. This experiment ought 
 only to be made in a bottle of very flrong green 
 glafs, holding not more than a pint, and wrap- 
 ped round with twine, otherwife the operator 
 will be expofed to great danger from the rup- 
 ture of the bottle, of which the fragments will 
 be thrown about with great force. 
 
 If all that has been related above, concerning 
 the decompofition of water, be exactly conform- 
 able to truth ; — if, as I have endeavoured to 
 prove, that fubftance be really compofed of hy. 
 drogen, as its proper conftituent element, com- 
 bined with oxygen, it ought to follow, that, by 
 reuniting thefe two elements together, we fhould 
 recompofe water; and that this actually hap- 
 pens may be judged of by the following experi- 
 ment. 
 
 Experiment fourth . 
 
 I took a large criftal baloon, A , PL iv. fig. 5. 
 holding about 30 pints, having a large opening, 
 to which was cemented the plate of copper BC, 
 pierced with four holes, in which four tubes 
 terminate. The firfl tube, H h, is intended to 
 
 be 
 
Elements 
 
 9 * 
 
 be adapted to an air pump, by which the baloon 
 is to be exhaufted of its air. The fecond tube 
 gg, communicates, by its extremity MM, witli 
 a refervoir of oxygen gas, with which the ba- 
 loon is to be filled. The third tube d D d% 
 communicates, by its extremity d NN, with a 
 refervoir of hydrogen gas. The extremity d* 
 of this tube terminates in a capillary opening, 
 through which the hydrogen gas contained in 
 the refervoir is forced, with a moderate degree 
 of quicknefs, by the preflure of one or two inch- 
 es of water. The fourth tube contains a me- 
 tallic wire GL, having a knob at its extremity 
 L, intended for giving an electrical fpark from 
 L to d% on purpofe to fet fire to the hydrogen 
 gas : This wire is moveable in the tube, that 
 we may be able to feparate the knob L from 
 the extremity d’ of the tube Dd’. The three 
 tubes d D d’, gg, and H h, are all provided with 
 flop-cocks. 
 
 That the hydrogen gas and oxygen gas may 
 be as much as pofiible deprived of water, they 
 are made to pafs, in their way to the baloon A, 
 through the tubes MM, NN, of about an inch 
 diameter, and filled with falts, which, from their 
 deliquefcent nature, greedily attract the moif- 
 ture of the air : Such are the acetite of pofalh, 
 and the muriat or nitrat of lime *. Thefe falts 
 
 mult 
 
 * See the nature of thefe falts in the fecond part of 
 f;his book. — A. 
 
OF CHEMISTRY. 
 
 93 
 
 muft only be reduced to a coarfe powder, left 
 they run into lumps, and prevent the gaffes from 
 geting through their interfaces. 
 
 We muft be provided before hand with a fuf- 
 ficient quantity of oxygen gas, carefuUy puri- 
 fied from all admixture of carbonic acid, by 
 long contact with a folution of potafli 
 
 We muft likewife have a double quantity of 
 hydrogen gas, carefully purified in the fame 
 manner by long contact with a folution of pot- 
 afh in water. The beft way of obtaining this 
 gas free from mixture is, by decompofing water 
 with very pure foft iron, as directed in Exp. 3. 
 of this chapter. 
 
 Having adjufled every thing properly, as a- 
 bove directed, the tube H h is adapted to an air- 
 pump, and the baloon A is exhaufled of its air. 
 We next admit the oxygen gas fo as to fill the 
 baloon, and then, by means of preffure, as is 
 before mentioned, force a fmall ftream of hy- 
 drogen gas through its tube D d\ which we 
 immediately fet on fire by an electric fpark. By 
 means of the above defcribed apparatus, we can 
 
 continue 
 
 * By potafli is here meant, pure cr cauftic alkali, 
 deprived of carbonic acid by means of quick-lime: In 
 general, we may obferve here, that all the alkalies and 
 earths mull invariably be confidered as in their pure 
 or cauftic ftatc, unlefs otherwife exprefled. — E. The 
 method of obtaining this pure alkali of potafli will be 
 given in the fequel— A. 
 
ELEMENTS 
 
 $4 
 
 continue the mutual combuftion of thefe two 
 gaffes for a long time, as we have the power of 
 fupplying them to the baloon from their refer- 
 voirs, in proportion as they are confumed. I 
 have in another place * given a defcription of 
 the apparatus ufed in this experiment, and have 
 explained the manner of afcertaining the quan- 
 tities of the gaffes confumed with the moft fcru- 
 pulous exactitude. 
 
 In proportion to the advancement of the com- 
 buftion, there is a depofition of water upon the 
 inner furface of the baloon or matrafs A : The 
 water gradually increafes in quantity, and, ga- 
 thering into large drops, runs down to the bot- 
 tom of the veffeL It is eafy to afcertain the 
 quantity of water colle&ed, by weighing the 
 baloon both before and after the experiment. 
 Thus we have a twofold verification of our ex- 
 periment, by afcertaining both the quantities of 
 the gaffes employed, and of the water formed 
 by their combuftion : Thefe two quantities muff 
 be equal to each other. By an operation of this 
 kind, Mr Meufnier and I afcertained that it 
 required 85 parts, by weight, of oxygen, united 
 to 15 parts of hydrogen, to compofe 100 parts 
 of water. This experiment, which has not 
 hitherto been publifhed, was made in prefence 
 of a numerous committee from the Royal Aca- 
 demy, 
 
 * See the third part of this work — A. 
 
F C H E M I S T R Y„ 
 
 >5 
 
 demy. We exerted the moft fcrupulous atten- 
 tion to its accuracy ; and have reafon to believe 
 that the above propofitions cannot vary a two 
 hundredth part from abfolute truth. 
 
 From thefe experiments, both analytical and 
 fvnthetic, we may now affirm that we have af- 
 certained, with as much certainty as is poffible 
 in phyfical or chemical fubje&s, that water is 
 not a fimple elementary fubftance, but is coni- 
 pofed of two elements, oxygen and hydrogen ; 
 which elements, when exifting feparately, have 
 fo ftrong affinity for caloric, as only to fubfifh 
 under the form of gas in the common tempe- 
 rature and preflure of our atmofphere. 
 
 This decompofition and recompofition of wa- 
 ter is perpetually operating before our eyes, in 
 the temperature of the atmofphere, by means of 
 compound elective attraction. We fnali pre- 
 fently fee that the phenomena attendant upon 
 vinous fermentation, putrefaction, and even 
 vegetation, are produced, at leafh in a certain 
 degree, by decompofition of water. It is very 
 extraordinary that this fact fhould have hitherto 
 been overlooked by natural phiiofophers and 
 chemifts : Indeed, it ftrongly proves, that, in 
 chemiftry, as in moral philofophy, it is extreme- 
 ly difficult to overcome prejudices imbibed in 
 early education, and to fearch for truth in any 
 other road than the one we have been accuflom- 
 ed to follow. 
 
 T 
 
§6 ELEMENTS 
 
 I fhall finifli this chapter by an experiment: 
 much lefs demonflrative than thofe already re- 
 lated, but which has appeared to make more im- 
 preffion than any other upon the minds of many 
 people. When 1 6 ounces of alkohol are burnt 
 in an apparatus # properly adapted for collec- 
 ting all the water difengaged during the corn- 
 bullion, we obtain from 17 to 18 ounces of wa- 
 ter. As no fubftance can furnilh a product lar- 
 ger than its original bulk, it follows, that fome- 
 thing elfe has united with the alkohol during its 
 combuliion ; and I have already fhown that this 
 mull be oxygen, or the bafe of air. Thus al- 
 kohol contains hydrogen, which is one of the 
 elements of water; and the atmofpheric air con- 
 tains oxygen, which is the other element necef- 
 fary to the compofition of water. This experi- 
 ment is a new proof that water is a compound 
 fubftance. 
 
 CHAP. 
 
 * See an account of this apparatus in the third part 
 of this work. — A, 
 
OF CHEMISTRY. 
 
 97 
 
 CHAP. IX. 
 
 Of the quantities of Caloric dif engaged from diffe- 
 rent fpecies of Combuflion. 
 
 W E have already mentioned, that, when 
 any body is burnt in the center of a 
 hollow fphere of ice and fupplied with air at 
 the temperature of zero (32°), the quantity of 
 ice melted from the infide of the fphere becomes 
 a meafure of the relative quantities of caloric 
 difengaged. Mr de la Place and I gave a de- 
 fcription of the apparatus employed for this kind 
 of experiment in the Memoirs of the Academy 
 for 1780, p. 355.; and a defcription and plate 
 of the fame apparatus will be found in the third 
 part of this work. With this apparatus, phof- 
 phorus, charcoal, and hydrogen gas, gave the 
 following refults : 
 
 One pound of phofphorus melted 100 libs . of 
 ice. 
 
 One pound of charcoal melted 96 libs. 8 oz. 
 One pound of hydrogen gas melted 295 libs. 
 9 oz • 3 t 8 r0St 
 
 As a concrete acid is formed by the conibuf- 
 tion of phofphorus, it is probable that very 
 little caloric remains in the acid, and, confe- 
 JNf quently. 
 
• 9 S 
 
 ELEMENTS 
 
 quently, that the above experiment gives ns very 
 nearly the whole quantity of caloric contained 
 in the oxygen gas. Even if we fuppofe the 
 phofphoric acid to contain a good deal of calo- 
 ric, yet, as the phofphorus mull have contained 
 nearly an equal quantity before combuftion, the 
 error muff be very fmall, as it will only confift 
 of the difference between what was contained 
 in the phofphorus before, and in the phofphp- 
 ric acid after combuftion. 
 
 I have already fhown in Chap. V. that one 
 pound of phofphorus abforbs one pound eight 
 ounces of oxygen during combuftion ; and 
 fince, by the fame operation, ioo lib . of ice are 
 melted, it follows, that the quantity of calo- 
 ric contained in one pound of oxygen gas is 
 capable of melting 66 libs. 10 oz. $gros 24 grs* 
 of ice. 
 
 One pound of charcoal during combuftion 
 melts only 96 libs . 8 oz. of ice, whilft it abforbs 
 2 libs. 9 oz. 1 gros 10 grs . of oxygen. By the ex- 
 periment with phofphorus, this quantity of oxy- 
 gen gas ought to difengage a quantity of caloric 
 fuflicient to melt 171 libs . 6 oz. 5 gros. of ice; 
 confequently, during this experiment, a quan- 
 tity of caloric, fuflicient to melt 74 libs. 14 oz. 
 5 gros of ice difappears. Carbonic acid is not, 
 like phofphoric acid, in a concrete ftate after 
 combuftion but in the ftate of gas, and re- 
 quires to be united with caloric to enable it to 
 
 fubfift 
 
OF CHEMISTRY. 
 
 99 
 
 fubfift in that ftate ; the quantity of caloric 
 miffing in the laft experiment is evidently em- 
 ployed for that purpofe. When we divide that 
 quantity by the weight of carbonic acid, formed 
 by the combuftion of one pound of charcoal, 
 we find that the quantity of caloric n&ceflary for 
 changing one pound of carbonic acid from the 
 concrete to the gaffeous ftate, would be capable 
 of melting 20 libs . 1 5 oz. 5 gros of ice. 
 
 We may make a fimilar calculation with the 
 combuftion of hydrogen gas and the confequent 
 formation of water. During the combuftion of 
 one pound of hydrogen gas, 5 libs . 10 oz. 5 
 gros 24 grs. of oxygen gas are abforbed, and 
 295 libs. 9 oz. 3^- gros of ice are melted. But 
 5 libs. 10 oz. 5 gros 24 grs. of oxygen gas, in 
 changing from the aeriform to the folid ftate, 
 lofes, according to the experiment with phof- 
 phorus, enough of caloric to have melted 377 
 libs. 12 oz. 3 gros of ice. There is only difen* 
 gaged, from the fame quantity of oxygen, du- 
 ring its combuftion with hydrogen gas, as much 
 caloric as melts 295 libs, 2 oz. 3-^ gros; where- 
 fore there remains in the water at Zero (32 0 ), 
 formed, during this experiment, as much calo- 
 ric as would melt 82 libs. 9 oz. 74 gros of ice. 
 
 Hence, as 6 libs . 10 oz. 5 gros 24 grs. of wa- 
 ter are formed from the combuftion of one 
 pound of hydrogen gas with 5 libs. 10 oz. 
 5 gros 24 grs. of oxygen, it follows that, in each 
 
 pound 
 
IOO 
 
 ELEMENTS 
 
 pound of water, at the temperature of Zero, 
 (3 2°), there exifts as much caloric as would 
 melt 12 libs. 5 oz. 2 gros 48 grs. of ice, with- 
 out taking into account the quantity originally 
 contained in the hydrogen gas, which we have 
 been obliged to omit, for want of data to cal- 
 culate its quantity. From this it appears that 
 water, even in the ftate of ice, contains a conft- 
 derable quantity of caloric, and that oxygen, in 
 entering into that combination, retains likewife 
 a good proportion. 
 
 From thefe experiments, we may alfume the 
 following refults as fufficiently eftablifhed. 
 
 Combuftion of Phofphorus. 
 
 From the combuftion of phofphorus, as rela- 
 ted in the foregoing experiments, it appears, 
 that one pound of phofphorus requires 1 lib. 
 8 oz. of oxygen gas for its combuftion, and 
 that 2 libs. 8 oz. of concrete phofphork acid are 
 produced. 
 
 The quantity of caloric difengaged by the- 
 combuftion of one pound of phofphorus, ex- 
 preffed by the number of pounds of ice melted 
 during that operation, is . 100.00000. 
 
 The quantity difengaged from each pound of 
 oxygen, during the combuftion of phofphorus, 
 exprelfed in the fame manner, is 66.66667. 
 
 The quantity difengaged during the forma- 
 tion 
 
OF CHEMISTRY- 
 
 101 
 
 tion of one pound of phofphoric acid, 40.00000 
 The quantity remaining in each pound of phof- 
 phoric acid, 0.00000 ** 
 
 Combuftion of Charcoal . 
 
 In the combuftion of one pound of charcoal, 
 2 libs . 9 oz. 1 gros 10 grs. of oxygen gas are 
 abforbed, and 3 libs* 9 oz. 1 gros 10 grs. of car- 
 bonic acid gas are formed. 
 
 Caloric, difengaged during the combuftion 
 of one pound of charcoal, 96.50000 f. 
 
 Caloric difengaged during the combuftion of 
 charcoal, from each pound of oxygen gas ab- 
 forbed, 37.52823. 
 
 Caloric difengaged during the formation of 
 one pound of carbonic acid gas, 27.02024. 
 
 Caloric retained by each pound of oxygen 
 after the combuftion 29.13844 
 
 Caloric neceflary for fupporting one pound 
 of carbonic acid in the ftate of gas 20.97960. 
 
 Com - 
 
 * We here fuppofe the phofphoric acid not to con- 
 tain any caloric, which is not ftritf ly true ; but, as 
 I have before dbferved, the quantity it really contains 
 is probably very fmall, and We have not given it a va- 
 lue, for want of a fufficicnt data to go upon.— A. 
 
 f All thefe relative quantities of caloric are exprefled 
 by the number of pounds of ice, and decimal parts, 
 melted during the feveral operations,— E. 
 
ELEMENTS 
 
 r*os 
 
 Combujlion of Hydrogen Gas . 
 
 In the combuftion of one pound of hydrogen 
 gas, 5 libs . io oz. 5 gros 24 grr. of oxygen gas 
 are abforbed, and 6 libs. 10 oz. 5 gros 24 grs. 
 of water are formed. 
 
 Caloric from each lib. of hydro- 
 gen gas, 295.58950. 
 
 Caloric from each lib. of oxygen 
 
 gas, 52.16280. 
 
 Caloric difengaged during the 
 formation of each pound of 
 water, 44.33840. 
 
 Caloric retained by each lib. of 
 oxygen after combuftion with 
 hydrogen 14.50386. 
 
 Caloric retained by each lib. of 
 water at the temperature of 
 Zero (32 0 ) 12.32823. 
 
 Of the Formation of Nitric Acid . 
 
 When we combine nitrous gas with oxygen 
 gas, fo as to form nitric or nitrous acid a de- 
 gree of heat is produced, which is much lefs 
 confiderable than what is evolved during the 
 other combinations of oxygen ; whence it follows 
 that oxygen, when it becomes fixed in nitric a- 
 cid, retains a great part of the heat which it pof- 
 
 Idled 
 
OF CHEMISTRY. 
 
 103 
 
 feffed in the date of gas. It is certainly pof- 
 fible to determine the quantity of caloric which 
 is difengaged during the combination of thefe 
 two gaffes, and confequently to determine what 
 quantity remains after the combination takes 
 place. The firft of thefe quantities might be 
 afcertained, by making the combination of the 
 two gaffes in an apparatus furrounded by ice 5; 
 but, as the quantity of caloric difengaged is 
 very inconfiderable, it would be neceffary to 
 operate upon a large quantity of the two gaffes 
 in a very troublefome and complicated appara- 
 tus. By this confideration, Mr de la Place and 
 I have hitherto been prevented from making 
 the attempt. In the mean time, the place of 
 fuch an experiment may be fupplied by calcula- 
 tions, the refults of which cannot be very far 
 from truth. 
 
 Mr de la Place and I deflagrated a conveni- 
 ent quantity of nitre and charcoal in an ice ap- 
 paratus, and found that twelve pounds of ice 
 were melted by the deflagration of one pound 
 of nitre. We {hall fee, in the fequel, that one 
 pound of nitre is compofed, as under, of 
 
 Potafh 7 oz. 6 gros 51.84^. = 4515.84^* 
 Dryacid 8 1 21.16 =4700.16. 
 
 The above quantity of dry acid is compofed 
 
 pf 
 
 Oxygen 
 
104 
 
 ELEMENTS! 
 
 Oxygen 6 os. 3 gw 66.34gr?. = 3738.34 grx. 
 Azote 1 5 25,82 = 961.82. 
 
 By this we find that, during the above defla- 
 gration, 2 gros 1 \gr. of charcoal have fuflered 
 combuftion, alongfl with 3738.34 gr*. or 6 oz. 
 3 gros 66.34 grs . of oxygen. Hence, fince 
 1 2 //'&r. of ice were melted during the combuf- 
 tion, it follows, that one pound of oxygen 
 burnt in the fame manner would have melted 
 29.58320 libs, of ice. To which the quantity 
 of caloric, retained by a pound of oxygen after 
 combining with charcoal to form carbonic acid 
 gas, being added, which was already afcertainedto 
 be capable of melting 29.13844 libs, of ice, we 
 have for the total quantity of caloric remaining 
 in a pound of oxygen, when combined with ni- 
 trous gas in the nitric acid 58.72164 ; which is 
 the number of pounds of ice the caloric re- 
 maining in the oxygen in that ftate is capable 
 of melting. 
 
 We have before feen that, in the ftate of oxy- 
 gen gas, it contained at leaft 66.66667 ; where- 
 fore it follows that, in combining with azote to 
 form nitric acid, it only lofes 7.94502. Far- 
 ther experiments upon this fubjed are neceffary 
 to afcertain how far the refults of this calcula- 
 tion may agree with dired fad. This enor- 
 mous quantity of caloric retained by oxygen in 
 its combinatiorl into nitric acid, explains the 
 
 caufe 
 
OF CHEMISTRY. 
 
 xo$ 
 
 caufe of the great difengagement of caloric du- 
 ring the deflagrations of nitre ; or, more ftrift- 
 ly fpeaking, upon all occafions of the decompo- 
 fition of nitric acid* 
 
 Of the Combujiion of Wax* 
 
 Having examined feveral cafes of fimple 
 combuftion, I mean now to give a few examples 
 of a more complex nature. One pound of wax- 
 taper being allowed to burn flowly in an ice 
 apparatus, melted 133 libs . 2 oz. Sr & ros °f lce * 
 According to my experiments in the Memoirs 
 of the Academy for 1784, p. 606, one pound 
 of wax-taper confifts of 1 5 oz. 1 gros 2$ grs. 
 of charcoal, and 2 oz . 6 gros 49 grs. of hydro - 
 gen. 
 
 By the foregoing ex- 
 periments, the above 
 quantity of charcoal 
 
 ought to melt 79*3939° ^ x * °f ice ? 
 
 and the hydrogen fliouid 
 
 melt 52.37605 
 
 In all 131.76995 libs. 
 
 Thus, we fee the quantity of caloric difen* 
 gaged from a burning taper, is pretty exactly 
 conformable to what was obtained by burning 
 feparately a quantity of charcoal and hydrogen 
 O equal 
 
ELEMENTS 
 
 io 6 
 
 equal to what enters into its compofition. Thefe 
 experiments with the taper were feveral times 
 repeated, fo that I have reafon to believe them 
 accurate. 
 
 Combujiion of Olive Oil '. 
 
 We included a burning lamp, containing a 
 determinate quantity of olive-oil, in the ordi- 
 nary apparatus, and, when the experiment was 
 finiflied, we afcertained exactly the quantities 
 of oil confumed, and of ice melted ; the refult 
 was, that, during the combuftion of one pound 
 of olive-oil, 148 libs . 14 oz. 1 gros of ice were 
 melted. By my experiments in the Memoirs^ 
 of the Academy for 1784, and of which the 
 following Chapter contains an abftract, it ap- 
 pears that one pound of olive-oil confifts of 1 2 
 oz. 5 gros 5 grs. of charcoal, and 3 oz. 2 gros 
 67 grs. of hydrogen. By the foregoing experi- 
 ments, that quantity of charcoal fhould melt 
 76.18723 libs • of ice, and the quantity of hy- 
 drogen in a pound of the oil fliould melt 
 62.15053 libs. The fum of thefe two gives 
 1 38.33776 libs, of ice, which the two conftituent 
 elements of the oil would have melted, had they 
 feparately fuffered combuftion, whereas the oil 
 really melted 148.88330 libs, which gives an 
 excefs of 10.54554 in the refult of the experi- 
 
 ment 
 
OF CHEMISTRY. 
 
 ment above the calculated refult, from data fur- 
 nifhed by former experiments. 
 
 This difference, which is by no means very 
 confiderable, may arife from errors which are 
 unavoidable in experiments of this nature, or 
 it may be owing to the compofition of oil 
 not being as yet exaflly afcertained. It proves, 
 however, that there is a great agreement be- 
 tween the refults of our experiments, refpe&ing 
 the combination of caloric, and thofe which re- 
 gard its difengagement. 
 
 The following defiderata ftill remain to be de- 
 termined, viz. What quantity of caloric is re- 
 tained by oxygen, after combining with metals, 
 fo as to convert them into oxyds ; What quan- 
 tity is contained by hydrogen, in its different 
 ilates of exiftence ; and to afcertain, with more 
 precifion than is hitherto attained, how much 
 caloric is difengaged during the formation of 
 water, as there ftill remain confiderable doubts 
 with refpeft to our prefent determination of this 
 point, which can only be removed by farther 
 experiments. We are at prefent occupied with 
 this inquiry ; and, when once thefe feveral 
 points are well afcertained, which we hope they 
 will foon be, we fhall probably be under the ne- 
 ceffity of making confiderable corre&ions upon 
 molt of the refults of the experiments and cal- 
 culations in this Chapter. I did not, however, 
 confider this as a fufficient reafon for with- 
 holding 
 
lt>$ ELEMENTS 
 
 holding fo much as is already known from 
 fuch as may be inclined to labour upon the 
 fame fubjeft* It is difficult, in our endeavours 
 to difcover the principles of a new fcience, to a- 
 void beginning by guefs-work ; and it is rarely 
 poflible to arrive at perfe&ion from the firft fet- 
 ting out. 
 
 CHAP- 
 
OF CHEMISTRY. to^ 
 
 4 
 
 CHAP. X. 
 
 Of the Combination of Combujlible Subjiances with 
 each other . 
 
 A S combuftible fubftances in general have 
 a great affinity for oxygen, they ought 
 likewife to attract, or tend to combine with 
 each other ; quae funt eadem uni tertio^funt eadem 
 inter fe ; and the axiom is found to be true. 
 Almoft all the metals, for inftance, are capable 
 of uniting with each other, and forming what 
 are called alloys *, in common language. Mod 
 of thefe, like all combinations, are fufceptible 
 of feveral degrees of faturation ; the greater 
 number of thefe alloys are more brittle than the 
 pure metals of which they are compofed, efpe- 
 daily when the metals alloyed together are con- 
 fiderably different in their degrees of fufibility. 
 To this difference in fufibility, part of the phe- 
 nomena attendant upon alloyage are owing, par- 
 ticularly the property of iron, called by work- 
 men 
 
 * This term alloy , which we have from the language 
 of the arts, ferves exceedingly well for diftinguifliing 
 all the combinations or intimate unions of metals with 
 each other, and is adopted in our new nomenclature 
 for that purpofe. — A. 
 
1 IO 
 
 ELEMENTS 
 
 men hotjhort. This kind of iron muft be con* 
 fidered as an alloy, or mixture of pure iron, 
 which is almoft infufible, with a fmall portion 
 of fome other metal which fufes in a much 
 lower degree of heat. So long as this alloy re- 
 mains cold, and both metals are in the folid 
 ftate, the mixture is malleable ; but, if heated 
 to a fufficient degree to liquify the more fufible 
 metal, the panicles of the liquid metal, which 
 are interpofed between the particles of the me- 
 tal remaining folid, muft deftroy their continu- 
 ity, and occafion the alloy to become brittle* 
 The alloys of mercury, with the other metals, 
 have ufually been called amalgams , and we fee 
 no inconvenience from continuing the ufeofthat 
 term. 
 
 Sulphur, phofphorus, and charcoal, readily 
 unite with metals. Combinations of fulphur 
 with metals are ufually named pyrites . Their 
 combinations with phofphorus and charcoal are 
 either not yet named, or have received new 
 names only of late ; fo that we have not fcru- 
 pled to change them according to our prin- 
 ciples. The combinations of metal and fulphur 
 we call fulphurets , thofe with phofphorus phof- 
 phurets , and thofe formed with charcoal carbu- 
 rets. Thefe denominations are extended to all 
 the combinations into which the above three 
 fubftances enter, without being previoufly oxy- 
 genated* 
 
OF CHEMISTRY, 
 
 si: 
 
 genated. Thus, the combination of fulphur 
 with potafh, or fixed vegetable alkali, is called 
 fulphuret of potafh ; that which it forms with 
 ammoniac, or volatile alkali, is termed fulphuret 
 of ammoniac . 
 
 Hydrogen is likewife capable of combining 
 with many combuftible fubflances. In the hate 
 of gas, it diflolves charcoal, fulphur, phofpho- 
 rus, and feveral metals ; we diflinguifh thefe 
 combinations by the terras, carbonated hydrogen 
 gas , fulphur at ed hydrogen gas , and phofphorated 
 hydrogen gas* The fulphurated hydrogen gas was 
 called hepatic air by former chemifts, or foetid 
 air from fulphur , by Mr Scheele. The virtues 
 of feveral mineral waters, and the foetid fme!l 
 of animal excrements, chiefly arife from the pre- 
 fence of this gas. The phofphorated hydrogen 
 gas is remarkable for the property, difcovered 
 by Mr Gengembre, of taking fire fpontaneoufly 
 upon getting into contadl with atmofpheric air, 
 or, what is better, with oxygen gas. r I his gas 
 has a ftrong flavour, refembiing that of putrid 
 filji ; and it is very probable that the phofpho- 
 refcent quality of fifn, in the ftate of putrefac- 
 tion, arifes from the efcape of this fpecies of 
 gas. When hydrogen and charcoal are combi- 
 ned together, without the intervention of calo- 
 ric, to bring the hydrogen into the flats of gas, 
 they form oil, which is either fixed or volatile, 
 according to the proportions of hydrogen and 
 
 char- 
 
%IZ ELEMENTS 
 
 charcoal in its compofition. The chief diffe- 
 rence between fixed or fat oils drawn from ve- 
 getables by expreffion, and volatile or effential 
 oils, is, that the former contains an excefs of 
 charcoal, which is feparated when the oils are 
 heated above the degree of boiling water $ 
 whereas the volatile oils, containing a juft pro- 
 portion of thefe two conftituent ingredients, are 
 not liable to be decompofed by that heat, but, 
 uniting with caloric into the gaffeous ftate, pafs 
 over in diftillation unchanged. 
 
 In the Memoirs of the Academy for 1784, 
 p. 593- I gave an account of my experiments 
 upon the compofition of oil and alkohol, by the 
 union of hydrogen with charcoal, and of their 
 combination with oxygen. By thefe experi- 
 ments, it appears that fixed oils combine with 
 oxygen during combuftion, and are thereby 
 converted into water and carbonic acid. By 
 means of calculation applied to the products of 
 thefe experiments, we find that fixed oil is com- 
 pofed of 2 1 parts, by weight, of hydrogen com- 
 bined with 79 parts of charcoal. Perhaps the 
 folid fubftances of an oily nature, fuch as wax, 
 contain a proportion of oxygen, to which they 
 owe their ftate of folidity. I am at prefent en- 
 gaged in a feries of experiments, which I hope 
 will throw great light upon this fubjeft. 
 
 It is worthy of being examined, whether hy- 
 drogen in its concrete ftate, uncombined with 
 
 caloric. 
 
OF CHEMISTRY. 
 
 Ix 3 
 
 caloric, be fufceptible of combination with ful- 
 phur, phofphorus, and the metals. There is 
 nothing that we know of, which, a priori , 
 ihould render thefe combinations impoffible ; 
 for combuftible bodies being in general fufcep- 
 tible of combination with each other, there is 
 no evident reafon for hydrogen being an excep- 
 tion to the rule : However, no direct experi- 
 ment as yet eftablifhes either the poffibility or 
 impoffibility of this union. Iron and zinc are 
 the moft likely, of all the metals, for entering 
 into combination with hydrogen ; but, as thefe 
 have the property of decompofmg water, and 
 as it is very difficult to get entirely free from 
 moifture in chemical experiments, it is hardly 
 poffible to determine whether the fmali portions 
 of hydrogen gas, obtained in certain experi- 
 ments with thefe metals, were previoufly com- 
 bined with the metal in the ftate of folid hydro- 
 gen, or if they were produced by the decompofi- 
 tion of a minute quantity of water. The more 
 care we take to prevent the prelence of water 
 in thefe experiments, the lefs is the quantity of 
 hydrogen gas procured ; and, when very accu- 
 rate precautions are employed, even that quan- 
 tity becomes hardly fenfible. 
 
 However this inquiry may turnout refpecting 
 the power of combuftible bodies, as fulphur, 
 phofphorus, and metals, to abforb hydrogen, 
 we are certain that they only abforb a very fmali 
 P poy- 
 
ELEMENTS 
 
 1 14 
 
 portion ; and that this combination, inftead of 
 being eflential to their conftitution, can only be 
 confidered as a foreign fubftance, which conta- 
 minates their purity. It is the province of the 
 advocates * for this fyftem to prove, by deci- 
 five experiments, the real exiftence of this com- 
 bined hydrogen, which they have hitherto only 
 done by conje&ures founded upon fuppofitions. 
 
 char 
 
 * By thefe are meant the fupporters of the phlogis- 
 tic theory, who at prefent confider hydrogen, or the 
 bafe of inflammable air, as the phlogifton of the cele- 
 brated Stahl. — E. 
 
OF CHEMISTRY. 
 
 XI 5 
 
 CHAP. XL 
 
 Vbfervations upon Oxyds and Acids with fever al 
 Bafes — and upon the Compofition of Animal and 
 Vegetable fubftances % 
 
 W E have, in Chap. V. and VIII. examin- 
 ed the produ&s refulting from the corn- 
 bullion of the four fimpie combuftible fubftan- 
 ces, fulphur, phofphorus, charcoal, and hydro- 
 gen : We have lhown, in Chap. X. that the 
 fimpie combuftible fubftances are capable of 
 combining with each other into compound com- 
 buftible fubftances, and have obferved that oils 
 in general, and particularly the fixed vegetable- 
 oils, belong to this clafs, being compofed of 
 hydrogen and charcoal. It remains, in this 
 chapter, to treat of the oxygenation of thefe 
 compound combuftible fubftances, and to {how 
 that there exift acids and oxyds having double 
 and triple bafes. Nature furnilhes us with nu- 
 merous examples of this kind of combinations, 
 by means of which, chiefly, (he is enabled to 
 produce a vaft variety of compounds from a 
 very limited number of elements, or fimpie fub- 
 ftances. 
 
 It 
 
lit ELEMENTS* 
 
 It was long ago well known, that, when mu- 
 riatic and nitric acids were mixed together, a 
 compound acid was formed, having properties 
 quite diftindt from thofe of either of the acids 
 taken feparately. This acid was called aqua 
 regia , from its moft celebrated property of dif- 
 folving gold, called king of metals by the alchy- 
 mifts. Mr Berthollet has diftindUy proved that 
 the peculiar properties of this acid arife from 
 the combined adtion of its two acidifiable bafes ; 
 and for this reafon we have judged it necelfary 
 to diftinguifh it by an appropriate name : That 
 of nitro- muriatic acid appears extremely appli- 
 cable, from its expreffing the nature of the two 
 fubftances which enter into its compofition. 
 
 This phenomenon of a double bafe in one 
 acid, which had formerly been obferved only in 
 the nitro-muriatic acid, occurs continually in 
 the vegetable kingdom, in which a fimple acid, 
 or one poffefled of a fingle acidifiable bafe, is 
 very rarely found. Almoft all the acids pro- 
 curable from this kingdom have bafes com- 
 pofed of charcoal and hydrogen, or of charcoal, 
 hydrogen, and phofphorus, combined with more 
 or lefs oxygen. All thefe bafes, whether double 
 or triple, are likewife formed into oxyds, ha- 
 ving lefs oxygen than is neceflary to give them 
 the properties of acids. The acids and oxyds 
 from the animal kingdom are ftill more com- 
 pound, as their bafes generally confifl: of a com- 
 bination 
 
OF CHEMISTRY. n 7 
 
 bination of charcoal, phofphorus, hydrogen, and 
 azote. 
 
 As it is but of late that I have acquired any 
 clear and didindt notions t)f thefe fubltances, I 
 fhall not, in this place, enlarge much upon the 
 fubjedt, which I mean to treat of very fully in 
 fome memoirs I am preparing to lay before the 
 Academy. Mod of my experiments are already 
 performed ; but, to be able to give exadl reports 
 of the refulting quantities, it is neceffary that 
 they be carefully repeated, and increafed in 
 number : Wherefore, I fhall only give a fhort 
 enumeration of the vegetable and animal acids 
 and oxyds, and terminate this article by a few 
 refledtions upon the compofition of vegetable 
 and animal bodies. 
 
 Sugar, mucus, under which term we include 
 the different kinds of gums, and darch, are ve- 
 getable oxyds, having hydrogen and charcoal 
 combined, in different proportions, as their ra- 
 dicals or bafes, and united with oxygen, fo as 
 to bring them to the date of oxyds. From the 
 date of oxyds they are capable of being chan- 
 ged into acids by the addition of a frefh quan- 
 tity of oxygen ; and, according to the degrees 
 of oxygenation, and the proportion of hydrogen 
 and charcoal in their bafes, they form the feve- 
 ral kinds of vegetable acids. 
 
 It would be eafy to apply the principles of 
 our nomenclature to give names to thefe vege- 
 table 
 
ELEMENTS 
 
 iiS 
 
 table acids and oxyds, by ufing the names of 
 the two fubftances which compofe their bafes t 
 They would thus become hydro-carbonous acids 
 and oxyds : In this method we might indicate 
 which of their elements exifted in excefs, with- 
 out circumlocution, after the manner ufed by 
 Mr Rouelle for naming vegetable extracts : He 
 calls thefe extraCto-refinous when the extractive 
 matter prevails in their compofition, and refino* 
 extractive when they contain a larger propor- 
 tion of refinous matter. Upon that plan, and 
 by varying the terminations according to the 
 formerly eftabiifhed rules of our nomenclature* 
 we have the following denominations : Hydrc- 
 carbonous, hydro-carbonic > carbono-hydrous, 
 and carbono-hydric oxyds. And for the acids s 
 Hydro-carbonous, hydro carbonic, oxygenated 
 hydro-carbonic ; carbono-hydrous, carbono-hy- 
 dric, and oxygenated carbono-hydric. It is 
 probable that the above terms would fuffice for 
 indicating all the varieties in nature, and that, 
 in proportion as the vegetable acids become well 
 underllood, they will naturally arrange them- 
 felves under thefe denominations. But, though 
 we know the elements of which thefe are com- 
 pofed, we are as yet ignorant of the proportions 
 of thefe ingredients, and are dill far from being 
 able to clafs them in the above methodical man- 
 ner 5 wherefore, we have determined to retain 
 
 the 
 
OF CHEMISTRY, 
 
 119 
 
 the ancient names provifionally. I am fome- 
 what farther advanced in this inquiry than at 
 the time of publifhing our conjunct elfay upon 
 chemical nomenclature ; yet it would be impro- 
 per to draw decided confequences from experi- 
 ments not yet fufficiently precife : Though I ac- 
 knowledge that this part of chemiftry {till re- 
 mains in fome degree obfcure, 1 muft exprefs 
 my expectations of its being very foon eluci- 
 dated. 
 
 I am {till more forcibly neceffitated to follow 
 the fame plan in naming the acids, which have 
 three or four elements combined in their bafes ; 
 of thefe we have a confiderable number from 
 the animal kingdom, and fome even from ve- 
 getable fubltances. Azote, for inflance, joined 
 to hydrogen and charcoal, form the bafe or ra- 
 dical of the Pruffic acid ; we have reafon to be- 
 lieve that the fame happens with the bafe of the 
 Gallic acid; and almoft all the animal acids have 
 their bafes compofed of azote, phofphorus, hy- 
 drogen, and charcoal. Were we to endeavour 
 to exprefs at once all thefe four component parts 
 of the bafes, our nomenclature would undoubt- 
 edly be methodical; it would have the property 
 of being clear and determinate ; but this affem- 
 blage of Greek and Latin fubftantives and ad- 
 jectives, which are not yet univerfally admitted 
 by chemifts, would have the appearance of a 
 
 barbarous 
 
120 
 
 ELEMENTS 
 
 barbarous language, difficult both to pronounce 
 and to be remembered. Befides, this part of 
 chemiftry being ftill far from that accuracy it 
 muft arrive to, the perfe&ion of the fcience 
 ought certainly to precede that of its language ; 
 and we muft ftill, for fome time, retain the old 
 names for the animal oxyds and acids. We 
 have only ventured to make a few flight modi- 
 fications of thefe names, by changing the ter- 
 mination into ous, when we have reafon to fup- 
 pofe the bafe to be in excefs, and into /V, when 
 we fufpeft the oxygen predominates. 
 
 The following are all the vegetable acids 
 hitherto known : 
 
 1. Acetous acid. 8. Pyro-mucous acid. 
 
 2. Acetic acid. 9. Pyro-lignous acid. 
 
 3. Oxalic acid. 10. Gallic acid. 
 
 4. Tartarous acid. 11. Benzoic acid. 
 
 5. Pyro-tartarous acid. 12. Camphoric acid. 
 
 6. Citric acid. 13. Succinic acid. 
 
 7. Malic acid. 
 
 Though all thefe acids, as has been already 
 faid, are chiefly, and almoft entirely, compofed 
 of hydrogen, charcoal, and oxygen, yet, proper- 
 ly fpeaking, they contain neither water carbo- 
 nic acid nor oil, but only the elements neceflary 
 for forming thefe fubftances. The power of 
 affinity reciprocally exerted by the hydrogen, 
 charcoal, and oxygen, in thefe acids,is in a ftate 
 
 of 
 
OF CHEMISTRY. 
 
 121 
 
 of equilibrium only capable of exifting in the 
 ordinary temperature of the atmofphere ; for, 
 when they are heated but a very little above 
 the temperature of boiling water, this equilibri- 
 um is deftroyed, part of the oxygen and hydro- 
 gen unite, and form water; part of the charcoal 
 and hydrogen combine into oil ; part of the 
 charcoal and oxygen unite to form carbonic 
 acid; and, laftly, there generally remains a fmall 
 portion of charcoal, which, being in excefs with 
 refpeft to the other ingredients, is left free. I 
 mean to explain this fubjeci: fomewhat farther in 
 the fucceeding chapter. 
 
 The oxyds of the animal kingdom are hither- 
 to lefs known than thofe from the vegetable 
 kingdom, and their number is as yet not at all 
 determined. The red part of the blood, lymph, 
 and moft of the fecretions, are true oxyds, un- 
 der which point of view it is very important to 
 confider them. We are only acquainted with 
 fix animal acids, feveral of which, it is pro- 
 bable, approach very near each other in their 
 nature, or, at leaft, differ only in a fcarcely fen- 
 fible degree. I do not include the phofphoric 
 acid amongfl thefe, becaufe it is found in all 
 the kingdoms of nature. They are, 
 
 1. La&ic acid. 4. Formic acid. 
 
 2. Saccho-la&ic acid. 5. Sebacic acid. 
 
 3. Bombic acid. 6. Pruffic acid. 
 
 O 
 
 The 
 
122 
 
 ELEMENTS 
 
 The connexion between the conftituent ele- 
 ments of the animal oxyds and acids is not 
 more permanent than in thofe from the vege- 
 table kingdom, as a fmall increafe of tempera- 
 ture is fufficient to overturn it. I hope to ren- 
 der this fubjeft more diftinQ: than has been done 
 hitherto in the following chapter. 
 
 > 
 
 CHAP. 
 
OF CHEMISTRY. 
 
 X23 
 
 CHAP. XII. 
 
 Of the Decompofition of Vegetable and Animal Sub * 
 fiances by the Ad ion of Fire . 
 
 B EFORE we can thoroughly comprehend 
 what takes place during the decompofi- 
 tion of vegetable fubftances by fire, we rnufl 
 take into confideration the nature of the ele- 
 ments which enter into their compofition, and 
 the different affinities which the particles of thefe 
 elements exert upon each other, and the affini- 
 ty which caloric poffeffes with them. The true 
 conftituent elements of vegetables are hydro- 
 gen, oxygen, and charcoal : Thefe are common 
 to all vegetables, and no vegetable can exift 
 without them : Such other fubftances as exift 
 in particular vegetables are only effential to the 
 compofition of thofe in which they are found, 
 and do not belong to vegetables in general. 
 
 Of thefe elements, hydrogen and oxygen have 
 a ftrong tendency to unite with caloric, and be 
 converted into gas, whilft charcoal is a fixed 
 element, having but little affinity with caloric. 
 On the other hand, oxygen, which, in the ufual 
 temperature, tends nearly equally to unite with 
 hydrogen and with charcoal, has a much ftrong- 
 
 er 
 
124 
 
 ELEMENTS 
 
 er affinity with charcoal when at the red heat % 
 and then unites with it to form carbonic acid. 
 
 Although we are far from being able to ap- 
 preciate all thefe powers of affinity, or to ex- 
 prefs their proportional energy by numbers, we 
 are certain, that, however variable they may be 
 when confidered in relation to the quantity of 
 caloric with which they are combined, they are 
 all nearly in equilibrium in the ufual tempera- 
 ture of the atmofphere ; hence vegetables nei- 
 ther contain oil f, water, nor carbonic acid, tho* 
 they contain all the elements of thefe fubftan- 
 ces. The hydrogen is neither combined with 
 the oxygen nor with the charcoal, and recipro- 
 cally; the particles of thefe three fubftances form 
 a triple combination, which remains in equili- 
 brium 
 
 * Though this term, red heat, does not indicate 
 any abfolutely determinate degree of temperature, I 
 fhall ufe it fometimes to exprefs a temperature confi- 
 derably above that of boiling water. — A. 
 
 f I mull be underltood here to fpeak of vegetables 
 reduced to a perfe&ly dry ftate ; and, with refpeft to 
 oil, I do not mean that which is procured by expref- 
 fion either in the cold, or in a temperature not exceed- 
 ing that of boiling water ; I only allude to the empy- 
 reumatic oil procured by diflillation with a naked fire* 
 in a heat fuperior to the temperature of boiling water \ 
 which is the only oil declared to be produced by the 
 operation of fire. What I have publifhed upon this 
 fubjett in the Memoirs of the Academy for 1786 may 
 be confulted — A. 
 
OF CHEMISTRY. 
 
 125 
 
 brlum whilft undifturbed by caloric but a very 
 flight increafe of temperature is fufficient to 
 overturn this ftru&ure of combination. 
 
 If the increafed temperature to which the ve- 
 getable is expofed does not exceed the heat of 
 boiling water, one part of the hydrogen com- 
 bines with the oxygen, and forms water, the 
 reft of the hydrogen combines with a part of 
 the charcoal, and forms volatile oil, whilft the 
 remainder of the charcoal, being fet free from 
 its combination with the other elements, re- 
 mains fixed in the bottom of the diftilling vef- 
 fel. 
 
 When, on the contrary, we employ a red 
 heat, no water is formed, or, at leaft, any that 
 may have been produced by the firft applica- 
 tion of the heat is decompofed, the oxygen ha- 
 ving a greater affinity with the charcoal at this 
 degree of heat, combines with it to form car- 
 bonic acid, and the hydrogen being left free 
 from combination with the other elements, u- 
 nites with caloric, and efcapes in the ftate of 
 hydrogen gas. In this high temperature, either 
 no oil is formed, or, if any was produced du- 
 ring the lower temperature at the beginning of 
 the experiment, it is decompofed by the a&ion 
 of the red heat. Thus the decompofi tion of ve- 
 getable matter, under a high temperature, is 
 produced by the a&ion of double and triple af- 
 finities $ while the charcoal attracts the oxygen, 
 
 on 
 
12 ( 5 , ELEMENTS 
 
 on purpofe to form carbonic acid, the caloric 
 attra&s the hydrogen, and converts it into hy- 
 drogen gas. 
 
 The diftillation of every fpecies of vegetable 
 fub (lance confirms the truth of this theory, if we 
 can give that name to a fimple relation of fads. 
 When fugar is fubmitted to diftillation, fo long 
 as we only employ a heat but a little below that 
 of boiling water, it only lofes its water of crif- 
 tallization, it ftill remains fugar, and retains all 
 its properties ; but, immediately upon raifing 
 the heat only a little above that degree, it be- 
 comes blackened, a part of the charcoal fepa- 
 rates from the combination, water (lightly aci- 
 dulated paffes over accompanied by a little oil, 
 and the charcoal which remains in the retort is 
 nearly a third part of the original weight of the 
 fugar. 
 
 The operation of affinities which take place 
 during the decompofttion, by fire, of vegetables 
 which contain azote, fuch as the cruciferous 
 plants, and of thofe containing phofphorus, is 
 more complicated ; but, as thefe fubftances on- 
 ly enter into the compofition of vegetables in 
 very fmall quantities, they only, apparently, pro- 
 duce flight changes upon the produ&s of diftil- 
 lation ; the phofphorus feems to combine with 
 the charcoal, and, acquiring fixity from that 
 union, remains behind in the retort, while the 
 
 azote, 
 
OF CHEMISTRY. 
 
 127 
 
 azote, combining with a part of the hydrogen, 
 forms ammoniac, or volatile alkali. 
 
 Animal fubftances, being compofed nearly of 
 the fame elements with cruciferous plants, give 
 the fame products in diftillation, with this dif- 
 ference, that, as they contain a greater quanti- 
 ty of hydrogen and azote, they produce more 
 oil and more ammoniac. I fhall only produce 
 one faCt as a proof of the exaCtnefs with which 
 this theory explains all the phenomena which 
 occur during the diftillation of animal fubftan- 
 ces, which is the rectification and total decom- 
 pofition of volatile animal oil, commonly known 
 by the name of Dippel’s oil. When thefe oils 
 are procured by a firft diftillation in a naked 
 fire they are brown, from containing a little 
 charcoal almoft in a free ftate; but they become 
 quite colourlefs by rectification. Even in this 
 If ate the charcoal in their compofition has fo 
 flight a connection with the other elements as 
 to feparate by mere expofure to the air. If we 
 put a quantity of this animal oil,, well rectified, 
 and confequently clear, limpid, and tranfparent, 
 into a bell-glafs filled with oxygen gas over 
 mercury, in a fhort time the gas is much di- 
 minifhed, being abforbed by the oil, the oxy- 
 gen combining with the hydrogen of the oil 
 forms water, which finks to the bottom, at the 
 fame time the charcoal which was combined 
 with the hydrogen being fet free, manifefts itfelf 
 
 * by 
 
128 
 
 ELEMENTS 
 
 by rendering the oil black. Hence the only 
 way of preferving thefe oils colourlefs and tran- 
 fparent, is by keeping them in bottles perfectly 
 full and accurately corked, to hinder the con- 
 tact of air, which always difcolours them. 
 
 Succeflive rectifications of this oil furnifh 
 another phenomenon confirming our theory. In 
 each diftillation a fmall quantity of charcoal re- 
 mains in the retort, and a little water is formed 
 by t,he union of the oxygen contained in the 
 air of the diftilling veffds with the hydrogen of 
 the oil. As this takes place in each fucceflive 
 diftillation, if we make ufe of large veffels and 
 a confiderable degree of heat, we at laft decom- 
 pofe the whole of the oil, and change it entire- 
 ly into water and charcoal. When we ufe fmall 
 veffels, and efpecially when we employ a flow 
 fire, or degree of heat little above that of boil- 
 ing water, the total decompofition of thefe oils, 
 by repeated diftillation, is greatly more tedious, 
 and more difficultly accomplifhed. I fhall give 
 a particular detail to the Academy, in a feparate 
 memoir, of all my experiments upon the decom- 
 pofition of oil ; but what I have related above 
 may fuffice to give juft ideas of the compofition 
 of animal and vegetable fubftances, and of their 
 decompofition by the aCtion of fire. 
 
 CHAP. 
 
OF CHEMISTRY. 
 
 129 
 
 CHAP. XI IL 
 
 Of the Decompofition of Vegetable Oxyds by the Vi- 
 nous Fermentation . 
 
 T H E manner in which wine, cyder, mead, 
 and all the liquors formed by the fpiri- 
 tous fermentation, are produced, is well known 
 to every one. The juice of grapes or of apples 
 being expreffed, and the latter being diluted 
 with water, they are put into large vats, which 
 are kept in a temperature of at lead i o° (54*5°) 
 of the thermometer. A rapid inteftine motion, 
 or fermentation, very foon takes place, nume- 
 rous globules of gas form in the liquid and 
 burft at the furface ; when the fermentation is 
 at its height, the quantity of gas difengaged is 
 fo great as to make the liquor appear as if boil- 
 ing violently over a fire. When this gas is 
 carefully gathered, it is found to be carbonic 
 acid perfedly pure, and free from admixture 
 with any other fpecies of air or gas whatever. 
 
 When the fermentation is completed, the 
 juice of grapes is changed from being fweet, 
 and full of fugar, into a vinous liquor which no 
 longer contains any fugar, and from which we 
 procure, by diftillation, an inflammable liquor, 
 
 R known 
 
known in commerce under the name of Spirit 
 of Wine. As this liquor is produced by the 
 fermentation of any faccharine matter whatever 
 diluted with water, it muff have been con- 
 trary to the principles of our nomenclature to 
 call it fpirit of wine rather than fpirit of cyder, 
 or of fermented fugar ; wherefore, we have a- 
 dopted a more general term, and the Arabic 
 word alkobol feems extremely proper for the 
 purpofe. 
 
 This operation i$ one of the mpfl extraordi- 
 nary in chemiftry : We mult examine whence 
 proceed the difengaged carbonic acid and the 
 inflammable liquor produced, and in what 
 manner a fweet vegetable oxyd becomes thus 
 converted into two fuch oppofite fubftances, 
 whereof one is combuftible, and the other 
 eminently the contrary. To folve thefe two 
 queftions, it is neceffary to be previoufly ac- 
 quainted with the analyfis of the fermentable 
 fubftance, and of the prod lifts of the fermenta- 
 tion. We may lay it down as an inconteftible 
 axiom, that, in all the operations of art and na- 
 ture, nothing is created ; an equal quantity of 
 matter exifts both before and after the experi- 
 ment ; the quality and quantity of the elements 
 remain precifely the fame ; and nothing takes 
 place beyond changes and modifications in the 
 combination of thefe elements. Upon this prin- 
 ciple the whole art of performing chemical ex- 
 periments 
 
OF CHEMISTRY. 
 
 * 3 * 
 
 pertinents depends : We mu ft always fuppofe an 
 exad equality between the elements of the body- 
 examined and thofe of the produ&s of its ana- 
 lyfis. 
 
 Hence, fince from muft of grapes we procure 
 alkohol and carbonic acid, I have an undoubted 
 right to fuppofe that muft confifts of carbonic 
 acid and alkohol. From thefe premifes, we 
 have two methods of afcertaining what paffes 
 during vinous fermentation, by determining the 
 nature of, and the elements which compofe, the 
 fermentable fubftances, or by accurately exami- 
 ning the produ&s refulting from fermentation ; 
 and it is evident that the knowledge of either of 
 thefe muft lead to accurate conclufions concern- 
 ing the nature and compofition of the other. 
 From thefe confiderations,it became neceflary ac- 
 curately to determine the conftituent elements of 
 the fermentable fubftances ; and, for this pur- 
 pofe, 1 did not make ufe of the compound juices 
 of fruits, the rigorous analyfis of which is per- 
 haps impoflible, but made choice of fugar f 
 which is eafily analyfsd, and the nature of which 
 I have already explained. This fubflance is & 
 true vegetable oxyd with two bafes, compofed 
 of hydrogen and charcoal brought to the date 
 of an oxyd, by a certain proportion of oxygen ; 
 and thefe three elements are combined in fuch 
 a way, that a very flight force is fufficient to 
 deflroy the equilibrium of their connexion. By 
 
 a 
 
*3* ELEMENTS 
 
 a long train of experiments, made in various 
 ways, and often repeated, I afcertained that the 
 proportion in which thefe ingredients exift in 
 fugar, are nearly eight parts of hydrogen, 64 
 parts of oxygen, and 28 parts of charcoal, all 
 by weight, forming 100 parts of fugar. 
 
 Sugar mud be mixed with about four times 
 its weight of water, to render it fufceptible of 
 fermentation ; and even then the equilibrium 
 of its elements would remain undifturbed, with- 
 out the aftiftance of fome fubftance, to give a 
 commencement to the fermentation. This is 
 accomplifhed by means of a little yeaft from 
 beer ; and, when the fermentation is once ex- 
 cited, it continues of itfelf until completed. I 
 ihall, in another place, give an account of the 
 effects of yeaft, and other ferments, upon fer- 
 mentable fubftances. I have ufually employed 
 2 o libs . of yeaft, in the ftate of pafte, for each 
 1 00 libs . of fugar, with as much water as is four 
 times the weight of the lugar. I fhall give the 
 refults of my experiments exa&ly as they were 
 obtained, preferving even the fractions produ- 
 ced by calculation. 
 
 / 
 
 Tabls 
 
OF CHEMISTRY. 
 
 *34 
 
 Table I. Materials of Fermentation. 
 
 libs . oz.gr os grs. 
 
 Water • 400 000 
 
 Sugar - 100 000 
 
 Yealt in pafte, 10 libs* C Water - 7 3 6 44 
 
 compofed of £Dry yeaft - 2 12 1 28 
 
 Total 510 
 
 Table II. Conjlituent Elements of the Materials 
 of Fermentation . 
 
 libs. oZ. gros grs. 
 
 407 libs, 3 oz* 6 gros 44 grs. C Hydrogen 61 1 2 7 1.4O 
 
 of water, compofed of £ Oxygen 346 2 3 44.60 
 
 r Hydrogen 8000 
 loo libs, fugar, compofed of 4 Oxygen 64 o o o 
 
 i Charcoal 28 o o o 
 
 £ Hydrogen 045 0 * 3 ° 
 
 2 libs. i 2 oz. 1 gros iZgrs. of jOxygen 1 10 2 28.76 
 
 dry yeall, compofed of ^Charcoal o 12 4 59 
 
 ^Azote 005 2.94 
 
 Total weight 510 o o o 
 
 Table 
 

 *34 ELEMENTS 
 
 Table III. Recapitulation of thefe Elements 
 
 
 libs . 
 
 oz- 
 
 grosgrs. 
 
 
 
 
 
 f of the water 340 
 
 0 
 
 0 
 
 
 1 
 
 
 
 
 c 
 
 of the water 
 
 
 
 ° 1 
 
 | libs . 
 
 oz . 
 
 Pros pn. 
 
 £2^ in the yeaft 6 
 
 2 
 
 3 
 
 44.60 ; 
 
 ^411 
 
 1 
 
 12 
 
 6 
 
 1.36 
 
 q | of the fugar 64 
 
 0 
 
 0 
 
 ° 1 
 
 
 
 Lofthedryyeaft 1 
 
 10 
 
 2 
 
 28.76 j 
 
 1 
 
 
 
 
 a 
 
 ' of the water 60 
 
 0 
 
 0 
 
 0 1 
 
 1 
 
 
 
 
 V 
 
 to 
 
 of the water 
 
 
 
 I 
 
 
 
 
 O 
 
 h * 
 rri 
 
 in the yeaft 1 
 
 1 
 
 2 
 
 7 l - 4 ° ] 
 
 \ 69 
 
 6 
 
 0 
 
 8.70 
 
 r»- 
 
 of the fugar 8 
 
 0 
 
 0 
 
 0 1 
 
 1 
 
 
 
 
 w 
 
 of the dry yeaft 0 
 
 4 
 
 5 
 
 9 ' 3 °. 
 
 1 
 
 
 
 
 r • 
 
 M c 1 
 
 'of the fugar 28 
 > of the yeaft 0 
 
 0 
 
 12 
 
 0 
 
 4 
 
 0 1 
 
 59 -oo < 
 
 \ 28 
 
 12 
 
 4 59 -co 
 
 Azote of the yeaft 
 
 
 - 
 
 - 
 
 0 
 
 0 
 
 5 
 
 2.94 
 
 
 
 
 In 
 
 all 
 
 510 
 
 0 
 
 0 
 
 0 
 
 Having thus accurately determined the na- 
 ture and quantity of the conftituent elements of 
 the materials fubmitted to fermentation, we 
 have next to examine the produ&s refulting 
 from that procefs. For this purpofe, I placed 
 the above 510 libs, of fermentable liquor in a 
 proper * apparatus, by means of which I could 
 accurately determine the quantity and quality 
 of gas difengaged during the fermentation, and 
 could even weigh every one of the products 
 
 fepa* 
 
 * The above apparatus is defcribed ia the Third 
 Part.— 
 
*35 
 
 OF CHEMISTRY. 
 
 feparatelv, at any period of the procefs I judged 
 proper. An hour or two after the fubftances 
 are mixed together, efpecially if they are kept 
 in a temperature of from 1 5° (65.75*) t0 *8® 
 (72 .5°) of the thermometer, the firft: marks of 
 fermentation commence ; the liquor turns thick 
 and frothy, little globules of air are difengaged, 
 which rife and burft at the furface ; the quanti- 
 ty of thefe globules quickly increafes, and there 
 is a rapid and abundant produ&ion of very 
 puj-e carbonic acid, accompanied with a fcum, 
 which is the yeafl feparating from the mixture. 
 After fome days, lefs or more according to the 
 degree of heat, the inteftine motion and difen- 
 gagement of gas diminifh ; but thefe do not 
 ceafe entirely, nor is the fermentation com- 
 pleted for a considerable time. During the 
 procefs, 35 libs. 5 0 2?. 4 gros 19 grs. of dry car- 
 bonic acid are difengaged, which carry alongft 
 with them 13 libs. 14 oz. 5 gros of water. There 
 remains in the velfel 460 libs. 1 1 oz. 6 gros 53 
 grs. of vinous liquor, llightly acidulous. This 
 is at firft muddy, but clears of itfelf, and depo- 
 fits a portion of yeaft. When we feparately a- 
 nalife all thefe fubftances, which is effe&ed by 
 very troublefome procefies, we have the refults 
 as given in the following Tables. This pro- 
 cefs, with all the fubordinate calculations and 
 analyfes, will be detailed at large in the Me- 
 moirs of the Academy. 
 
 Table 
 
*3* ELEMENTS 
 
 Table IV. Products of Fermentation . 
 
 Oxygen 
 
 Charcoal 
 
 35 libs. 5 oz. $gros ig grs. 
 of carbonic acid, com- 
 pofed of 
 
 408 libs. i$oz. $ gros 14 grs. C Oxygen 
 of water, compofed of \ Hydrogen 
 
 libs. oz. 
 
 • 25 7 
 
 - 9 H 
 
 347 10 
 61 5 
 
 57 libs. 11 os. 1 g ros 5 8 
 
 of dry alkohol, compo- J W,th ox ^ e * 
 
 fed 0 £ 1 Hydrogen, combi- 
 
 'Oxygen, combined 
 with hydrogen 
 Hydrogen, combi- 
 ned with oxygen 
 
 Z libs. 8 oz. of dry ace- 
 tous acid, compofed 
 of 
 
 4 libs. 1 oz. 4 gros 3 grs. 
 of refidtium of l'ugar, 
 compofed of 
 
 I lib. 6 oz. Ogros 5 grs. 
 of dry yeaft, compofed 
 of 
 
 ned with charcoal 
 Charcoal, combined 
 __ with hydrogen 
 
 'Hydrogen 
 ' Oxygen 
 Charcoal 
 
 'Hydrogen 
 [ Oxygen 
 _ Charcoal 
 
 Hydrogen 
 Oxygen 
 1 Charcoal 
 Azote 
 
 3 i < 
 5 « 
 4 c 
 16 11 
 
 o 13 
 o 6 
 
 510 libs. 
 
 Total 510 o 
 
 gros grs, 
 
 1 34 
 
 2 57 
 
 o 59 
 4 27 
 
 1 64 
 
 5 3 
 5 o 
 
 5 63 
 
 4 o 
 4 0 
 
 0 o 
 
 1 67 
 7 27 
 
 2 53 
 
 2 41 
 
 1 14 
 
 2 20 
 2 37 
 
 o o 
 
 Table 
 
OF CHEMISTRY. 
 
 Table V. Recapitulation of the Products. 
 
 *37 
 
 libs, oz. gros grs 
 
 the 
 
 in the 
 
 libs. 8 oz. 6 gros 66 grj. 
 
 ed in the 
 
 f Water 
 
 347 10 
 
 0 
 
 59 
 
 f Carbonic acid 
 
 2 5 7 
 31 6 
 
 1 
 
 34 
 
 j Alkohol - , 
 
 1 
 
 64 
 
 • Acetous acid 
 
 1 ] r 
 
 4 
 
 0 
 
 | Refiduum of fugar 
 
 2 9 
 
 7 
 
 27 
 
 f Yeaft - 
 
 0 13 
 
 1 
 
 H 
 
 f Carbonic acid 
 
 9 14 
 
 2 
 
 57 
 
 | Alkohol 
 y Acetous acid 
 
 16 n 
 
 5 
 
 6 3 
 
 0 10 
 
 0 
 
 0 
 
 j Refiduum of fugar 
 
 1 2 
 
 2 
 
 53 
 
 {Yeaft 
 
 0 6 
 
 2 
 
 30 
 
 'Water 
 
 61 5 
 
 4 27 
 
 Water of the alkohol 
 Combined with the 
 
 5 8 
 
 5 
 
 3 
 
 <J charcoal of the alko. 
 
 4 0 
 
 5 
 
 0 
 
 Acetous acid 
 
 0 2 
 
 4 
 
 0 
 
 Refiduum of fugar 
 
 0 5 
 
 1 
 
 67 
 
 Yeaft 
 
 0 2 
 
 2 
 
 4 * 
 
 "s. of azote in the yeaft 
 
 0 0 
 
 2 
 
 37 
 
 510 libs. 
 
 Total 510 o o o 
 
 In thefe refults, I have been exa&, even to 
 grains ; not that it is poffible, in experiments 
 of this nature, to carry our accuracy fo far, but 
 as the experiments were made only with a few 
 pounds of fugar, and as, for the fake of com- 
 parifon, I reduced the refults of the actual ex- 
 periments to the quintal or imaginary hundred 
 S pounds. 
 
ELEMENTS 
 
 pounds, I thought it neceffary to leave the frac- 
 tional parts precifely as produced by calcula- 
 tion. 
 
 When we confider the refults prefented by 
 thefe tables with attention, it is eafy to difcover 
 exactly what occurs during fermentation. In 
 the frit place, out of the ioo libs . of fugar 
 employed, 4 libs . 1 oz. 4 gros 3 grs . re- 
 
 main, without having fuffered decompofition ; 
 fo that, in reality, we have only operated upon 
 95 libs. 14 oz. 3 gros 69 grs . of fugar ; that is 
 to fay, upon 6 1 libs. 6 oz. 45 grs. of oxygen, 
 7 libs. 10 oz. 6 gros 6 grs. of hydrogen, and 26 
 libs. 13 oz. 5 grGS 19 grs. of charcoal. By com- 
 paring thefe quantities, we find that they are 
 fully fufficient for forming the whole of the al- 
 kohol, carbonic acid and acetous acid produced 
 by the fermentation. It is not, therefore, ne- 
 ceflary to fuppoie that any water has been de- 
 compofed during the experiment, unlefs it be 
 pretended that the oxygen and hydrogen exift 
 in the fugar in that date. On the contrary, I 
 h^ve already made it evident that hydrogen, 
 oxygen and charcoal, the three condituent ele- 
 ments of vegetables, remain in a date of equi- 
 librium or mutual union with each other 
 which fubfds fo long as this union remains 
 tmdifturbed by increafed temperature, or by 
 fome new compound attraftion ; and that then 
 
 only 
 
OF CHEMISTRY, 
 
 *39 
 
 only thefe elements combine, two and two to- 
 gether, to form water and carbonic acid. 
 
 The effe&s of the vinous fermentation upon 
 fugar is thus reduced to the mere reparation of 
 its elements into two portions ; one part is oxy- 
 ( genated at the expence of the other, fo as to 
 > form carbonic acid, whilft the other part, being 
 | difoxyginated in favour of the former, is con- 
 Ij verted into the combuftible fubftance alkohol j 
 therefore, if it were poflible to reunite alkohol 
 and carbonic acid together, we ought to form 
 fugar. It is evident that the charcoal and hy- 
 drogen in the alkohol do not exiit in the hate 
 of oil, they are combined with a portion of 
 oxygen, which renders them mifcible with wa- 
 ter ; wherefore thefe three fubhances, oxygen, 
 hydrogen, and charcoal, exift here likewife in 
 a fpecies of equilibrium or reciprocal combina- 
 tion ; and in faff, when they are made to pafs 
 through a red hot tube of glafs or porcelain, 
 this union or equilibrium is defiroyed, the ele- 
 ments become combined, two and two, and wa- 
 ter and carbonic acid are formed* 
 
 I had formally advanced, in my krfl Me- 
 moirs upon the formation of water, that it was 
 decompofed in a great number of chemical ex- 
 periments, and particularly during the vinous 
 fermentation. I then fuppofed that water ex- 
 iked ready formed in fugar, though I am now 
 convinced that fugar only contains the elements 
 
 proper 
 
ELEMENTS 
 
 140 
 
 proper for compofing it. It may be readily con- 
 ceived, that it muft have coft me a good deal to 
 abandon my firft notions, but by feveral years 
 refle&ion, and after a great number of expert, 
 ments and obfervations upon vegetable fubftan- 
 ces, I have fixed my ideas as above. 
 
 I fhall finifh what I have to fay upon vinous 
 fermentation, by obferving, that it furnifhes us 
 with the means of analyfing fugar and every 
 vegetable fermentable matter. We may confi- 
 der the fubftances fubmitted to fermentation, 
 and the produdls refulting from that operation, 
 as forming an algebraic equation ; and, by fuc- 
 ceffively fuppofmg each of the elements in this 
 equation unknown, we can calculate their va- 
 lues in fucceffion, and thus verify our experi- 
 ments by calculation, and our calculation by ex- 
 periment reciprocally. I have often fuccefsfully 
 employed this method for corre&ing the firft 
 refults of my experiments, and to direft me in 
 the proper road for repeating them to advan- 
 tage. 1 have explained myfelf at large upon 
 this fubjefl:, in a Memoir upon vinous fermen- 
 tation already prefented to the Academy, and 
 which will fpeedily be publifhed. 
 
 C H A F. 
 
OF CHEMISTRY. x 4 ( 
 
 CHAP. XIV, 
 
 Of the Putrefattive Fermentation. 
 
 HE phenomena of putrefa&ion are caufed. 
 
 like thofe of vinous fermentation, by the 
 operation of very complicated affinities. The 
 conftituent elements of the bodies fubmitted to 
 this procefs ceafe to continue in equilibrium in 
 the threefold combination, and form themfelves 
 anew into binary combinations *, or compounds, 
 confiding of two elements only 7 but thefe are 
 entirely different from the refults produced by 
 the vinous fermentation. Inftead of one part 
 of the hydrogen remaining united with part of 
 the water and charcoal to form alkohol, as in 
 the vinous fermentation, the whole of the hy- 
 drogen is diffipated, during putrefadion, in the 
 form of hydrogen gas, whilft, at the fame time, 
 the oxygen and charcoal, uniting with caloric, 
 efcape in the form of carbonic acid gas ; fo 
 that, when the whole procefs is finilhed, efpeci- 
 
 * Binary combinations are fuch as confift of two 
 fimple elements combined together. Ternary, and 
 quaternary, confift of three and four elements. — 
 
 ally 
 
*4* ELEMENTS), 
 
 ally if the materials have been mixed with a 
 fufficient quantity of water, nothing remains 
 but the earth of the vegetable mixed with a 
 fmall portion of charcoal and iron. Thus pu- 
 trefaction is nothing more than a complete ana- 
 lyfis of vegetable fubftance, during which the 
 whole of the conftituent elements is difengaged 
 in form of gas, except the earth, which remains 
 in the flate of mould *. 
 
 Such is the refult of putrefaction when the 
 fubftances fubmitted to it contain only oxygen, 
 hydrogen, charcoal and a little earth. But 
 this cafe is rare, and thefe fubftances putrify im- 
 perfectly and with difficulty, and require a con- 
 fiderable time to complete their putrefaction. It 
 is otherwife with fubftances containing azote, 
 which indeed exifts in all animal matters, and 
 even in a confiderable number of vegetable fub- 
 ftances. This additional element is remarkably 
 favourable to putrefaction ; and for this reafon 
 animal matter is mixed with vegetable, when 
 the putrefaction of thefe is wiffied to be haften- 
 ed. The whole art of forming compofts and 
 dunghills, for the purpofes of agriculture, confifts 
 in the proper application of this admixture. 
 
 The addition of azote to the materials of 
 putrefaction not only accelerates the procefs, 
 
 that 
 
 * In the Third Part will be given the defcription of 
 an apparatus proper for being ufed in experiments of 
 ♦his kind. — A. 
 
OF CHEMISTRY. 
 
 *43 
 
 chat element likewife combines with part of the 
 hydrogen, and forms a new fubftance called 
 volatile alkali or ammoniac . The refults obtain- 
 ed by analyfing animal matters, by different 
 proceffes, leave no room for doubt with regard 
 to the conftituent elements of ammoniac ; when- 
 ever the azote has been previoufly feparated 
 from thefe fubftances, no ammoniac is produ- 
 ced ; and in all cafes they furnifh ammoniac 
 only in proportion to the azote they contain. 
 This compofition of ammoniac is likewife fully 
 proved by Mr Berthollet, in the Memoirs of 
 the Academy for 1785, p. 316. where he gives 
 a variety of analytical proceffes by which am- 
 moniac is decompofed, and its two elements, a- 
 zote and hydrogen, procured feparately. 
 
 I already mentioned in Chap. X. that almoft 
 all combuftible bodies were capable of combi- 
 ning with each other ; hydrogen gas poffeffes 
 this quality in an eminent degree, it diffolves 
 charcoal, fulphur, and phofphorus, producing 
 the compounds named carbonated hydrogen gas , 
 fulphurated hydrogen gas , and phofphorated hydro- 
 gen gas . The two latter of thefe gaffes have a 
 peculiarly difagreeable flavour \ the fulphurated 
 hydrogen gas has a ftrong refemblance to the 
 fmell of rotten eggs, and the phofphorated fmells 
 exa&ly like putrid fifh. Ammoniac has like- 
 wife a peculiar odour, not lefs penetrating, or 
 Jefs difagreeable, than thefe other gaffes. From 
 
 the 
 
*44 
 
 ELEMENTS 
 
 the mixture of thefe different flavours proceeds 
 the fetor which accompanies the putrefa&ion of 
 animal fubftances. Sometimes ammoniac pre- 
 dominates, which is eafily perceived by its 
 fharpnefs upon the eyes ; fometimes, as in fecu- 
 lent matters, the fulphurated gas is moft preva- 
 lent ; and fometimes, as in putrid herrings, the 
 phofphorated hydrogen gas is moft abundant. 
 
 I long fuppofed that nothing could derange 
 or interrupt the courfe of putrefa&ion $ but Mr 
 Fourcroy and Mr Thouret have obferved fome 
 peculiar phenomena in dead bodies, buried at a 
 certain depth, and preferved to a certain de- 
 gree, from contact with air ; having found the 
 mufcular flefh frequently converted into true a- 
 nimal fat. This muft have arifen from the dif- 
 engagement of the azote, naturally contained in 
 the animal fubftance, by fome unknown caufe, 
 leaving only the hydrogen and charcoal remain- 
 ing, which are the elements proper for produ- 
 cing fat or oil. This obfervation upon the 
 poffibiiity of converting animal fubftances into 
 fat may forne time or other lead to difcoveries 
 of great importance to fociety. The faeces of 
 animals, and other excrementitious matters, are 
 chiefly compofed of charcoal and hydrogen, and 
 approach confiderably to the nature of oil, of 
 which they furnifh a confiderable quantity by 
 diftillation with a naked fire j but the intole- 
 rable foetor which accompanies all the products 
 
 of 
 
 * 
 
OF CHEMISTRY. 
 
 *4J 
 
 of thefe fubftances prevents our expe&ing that, 
 at lead for a long time, they can be rendered 
 ufeful in any other way than as manures. 
 
 I have only given conje&ural approximations 
 in this Chapter upon the compofition of animal 
 fubftances, which is hitherto but imperfectly 
 underftood. We know that they are compofed 
 of hydrogen, charcoal, azote, phofphorus, and 
 fulphur, all of which, in a ftate of quintuple 
 combination, are brought to the ftate of oxyd 
 by a larger or fmaller quantity of oxygen. We 
 are, however, ftill unacquainted with the pro- 
 portions in which thefe fubftances are combi- 
 ned, and muft leave it to time to complete this 
 part of chemical analyfts, as it has already done 
 with feveral others. 
 
 T 
 
 CHAP. 
 
I4<S ELEMENTS 
 
 CHAP. XV. 
 
 Of the Acetous Fermentation . 
 
 r IPHE acetous fermentation is nothing more 
 JL than the acidification or oxygenation of 
 wine *, produced in the open air by means of 
 the abforption of oxygen. The refulting acid 
 is the acetous acid, commonly called Vinegar, 
 which is compofed of hydrogen and charcoal 
 united together in proportions not yet ascertain- 
 ed, and changed into the acid hate by oxygen. 
 As vinegar is an acid, we might conclude from 
 analogy that it contains oxygen, but this is put 
 beyond doubt by direct experiments : In the 
 firft place, we cannot change wine into vinegar 
 without the contadt of air containing oxygen ; 
 fecondly, this procefs is accompanied by a di- 
 minution of the volume of the air in which it 
 is carried on from the abforption of its oxygen ; 
 and, thirdly, wine may be changed into vinegar 
 by any other means of oxygenation. 
 
 Independent 
 
 * The word Wine, in this chapter, is ufed to iignify 
 the liquor produced by the vinous fermentation, what* 
 ever vegetable fubftance may have been ufed for ob- 
 taining it. — E. 
 
 A 
 
OF CHEMISTRY. 
 
 *47 
 
 Independent of the proofs which thefe fa£ls 
 furnifh of the acetous acid being produced by 
 the oxygenation of wine, an experiment made 
 by Mr Chaptal, Profeffor of Chemidry at Mont- 
 pellier, gives us a didind view of what takes 
 place in this procefs. He impregnated water 
 with about its own bulk of carbonic acid from 
 fermenting beer, and placed this water in a cel- 
 lar in veffels communicating with the air, and 
 in a fhort time the whole was converted into 
 acetous acid. The carbonic acid gas procured 
 from beer vats in fermentation is not perfectly 
 pure, but contains a fmall quantity of alkohol 
 in folution, wherefore water impregnated with 
 it contains all the materials neceflary for form- 
 ing the acetous acid. The alkohol furnifhes 
 hydrogen and one portion of charcoal, the car- 
 bonic acid furnifhes oxygen and the red of the 
 charcoal, and the air of the atmofphere furnifh- 
 es the red of the oxygen neceflary for changing 
 the mixture into acetous acid. From this ob- 
 fervation it follows, that nothing but hydrogen 
 is wanting to convert carbonic acid into acetous 
 acid; or more generally, that, by means of hy- 
 drogen, and according to the degree of oxyge- 
 nation, carbonic acid may be changed into all 
 the. vegetable acids; and, on the contrary, that, 
 by depriving any of the vegetable acids of their 
 hydrogen, they may be converted into carbonic 
 acid. 
 
 Although 
 
*48 ELEMENTS 
 
 Although the principal fads relating to the 
 acetous acid are well known, yet numerical ex- 
 actitude is ftiil wanting, till furnifhed by more 
 exadt experiments than any hitherto performed j 
 wherefore I fhall not enlarge any farther upon 
 the fubjed. It is fufficiently fhown by what 
 has been faid, that the conftitution of all the 
 vegetable acids and oxyds is exactly conform- 
 able to the formation of vinegar ; but farther 
 experiments are neceffary to teach us the pro- 
 portion of the conftituent elements in all thefe 
 acids and o^yds. We may eafily perceive, how- 
 i ever, that this part of chemiftry, like all the reft 
 of its divifions, makes rapid progrefs towards 
 perfection, and that it is already rendered great- 
 ly more fimple than was formerly believed. 
 
 CHAP. 
 
OF CHEMISTRY. 
 
 149 
 
 CHAP. XVI. 
 
 Of the Formation of Neutral Salts , and of their 
 different Bafes * 
 
 E have juft feen that all the oxyds and 
 
 acids from the animal and vegetable 
 
 kingdoms are formed by means of a fmall num- 
 ber of fimple elements, or at leaft of fuch as have 
 not hitherto been fufceptible of decompofition, 
 by means of combination with oxygen ; thefe 
 are azote, fulphur, phofphorus, charcoal, hy- 
 drogen, and the muriatic radical *. We may 
 juftly admire the fimplicity of the means env 
 ployed by nature to multiply qualities and forms, 
 whether by combining three or four acidifiable 
 bafes in different proportions, or by altering the 
 dofe of oxygen employed for oxydating or aci- 
 difying them. We ihall find the means no lefs 
 fimple and diverfified, and as abundantly pro- 
 du&ive of forms and qualities, in the order of 
 bodies we are now about to treat of. 
 
 * I have not ventured to omit this llement, as here 
 enumerated with the other principles of animal and 
 vegetable fubftances, though it is not at all taken no- 
 tice of in the preceding chapters as entering Into the 
 compofition of thefe bodies. — E> 
 
 Acidifiable 
 
ELEMENTS 
 
 150 
 
 Acidifiable fubftances, by combining with 
 oxygen, and their conlequent converfion into 
 acids, acquire great fufceptibility of farther com- 
 bination ; they become capable of uniting with 
 earthy and metallic bodies, by which means 
 neutral falts are formed. Acids may therefore 
 be conlidered as true falifying principles, and 
 the fubftances with which they unite to form 
 neutral ialts may be called falifiable bafes : The 
 nature of the union which thefe two principles 
 form with each other is meant as the fubject of 
 the prefent chapter. 
 
 This view of the acids prevents me from con- 
 fidering them as falts, though they are poflefted 
 of many of the principal properties of faline 
 bodies, as folubility in water, &c. I have al- 
 ready obferved that they are the refult of a firft 
 order of combination, being compofed of two 
 fimple elements, or at leaft of elements which 
 a ft as if they were fimple, and we may there- 
 fore rank them, to ufe the language of Stahl, 
 in the order of mixts. The neutral falts, on the 
 contrary, are of a fecondary order of combina- 
 tion, being formed by the union of two mixts 
 with each other, and may therefore be termed 
 compounds . Hence I fhall not arrange the alka- 
 lies * or earths in the clafs of falts, to which I 
 
 allot 
 
 * Perhaps my thus reje&ing the alkalies from the 
 clafs of falts may be confidered as a capital defeat in 
 
 the 
 
OF CHEMISTRY. 15* 
 
 allot only fuch as are compofed of an oxygena- 
 ted fubftance united to a bafe. 
 
 I have already enlarged fufficiently upon the 
 formation of acids in the preceding chapter, 
 and fhali not add any thing farther upon that 
 fubje£t ; but having as yet given no account of 
 the falifiable bafes which are capable of uniting 1 " 
 with them to form neutral falts, I mean, in this 
 chapter, to give an account of the nature and 
 origin of each of thefe bafes. Thefe are potafh, 
 foda, ammoniac, lime, magnefia, barytes, ar- 
 gill *, and all the metallic bodies. 
 
 § 1. Of Pota/h. 
 
 We have already fhown, that, when a vege- 
 table fubftance is fubmitted to the adlion of fire 
 in diftilling veifels, its component elements, oxy- 
 gen, hydrogen, and charcoal, which formed a 
 threefold combination in a ftate of equilibrium, 
 unite, two and two, in obedience to affinities 
 which a& conformable to the degree of heat 
 
 employed. 
 
 the method I have adopted, and [ am ready to admit 
 the charge-; but this inconvenience is compenfated 
 by fo many advantages, that I could not think it of 
 fufficient confequence to make me alter my plan. — A. 
 
 * Called Alumine by Mr Lavoifier ; but as Argil! 
 has been in a manner naturalized to the language for 
 this fubftance by Mr Kirwan, I have ventured to ufe 
 it in preference. — E. 
 
employed. Thus, at the fir ft application of the 
 fire, whenever the heat produced exceeds the 
 temperature of boiling water, part of the oxy- 
 gen and hydrogen unite to form water ; foon 
 after the reft of the hydrogen, and part of the 
 charcoal, combine into oil ; and, laftly, when 
 the fire is pufhed to the red heat, the oil and 
 water, which had been formed in the early part 
 of the procefs, become again decompofed, the 
 oxygen and charcoal unite to form carbonic 
 acid, a large quantity of hydrogen gas is fet 
 free, and nothing but charcoal remains in the 
 retort. 
 
 A great part of thefe phenomena occur du- 
 ring the combuftion of vegetables in the open 
 air ; but, in this cafe, the prefence of the air in- 
 troduces three new fubftances, the oxygen and 
 azote of the air and caloric, of which two at 
 leaft produce confiderable changes in the refults 
 of the operation. In proportion as the hydro- 
 gen of the vegetable, or that which refults from 
 the decompofition of the water, is forced out in 
 the form of hydrogen gas by the progref? of the 
 fire, it is fet on fire immediately upon getting 
 in contaft with the air, water is again formed, 
 and the greater part of the caloric of the two 
 gaffes becoming free produces flame. When 
 all the hydrogen gas is driven out, burnt, and 
 again reduced to water, the remaining charcoal 
 continues to burn, but without flame; it is 
 
 formed 
 
OF CHEMISTRY. 
 
 ,*53 
 
 formed into carbonic acid, which carries off a 
 portion of caloric fufficient to give it the gaffe- 
 ous form ; the reft of the caloric, from the oxy- 
 gen of the air, being fet free, produces the 
 heat and light obferved during the combuftion 
 of charcoal. The whole vegetable is thus re- 
 duced into water and carbonic acid, and no- 
 thing remains but a fmall portion of gray earthy 
 matter called allies, being the only really fixed 
 principles which enter into the conftitution of 
 vegetables. 
 
 The earth, or rather allies, which feldom ex- 
 ceeds a twentieth part of the weight of the vege- 
 table, contains a fubftance of a particular na- 
 ture, knowm under the name of fixed vegetable 
 alkali, or potalh. To obtain it, water is poured 
 upon the allies, which diffolves the potalh, 
 and leaves the allies which are infoluble ; by af- 
 terwards evaporating the water, we obtain the 
 potalh in a white concrete form : It is very fixed 
 even in a very high degree of heat. I do not 
 mean here to defcribe the art of preparing pot- 
 alh, or the method of procuring it in a ftate of 
 purity, but have entered upon the above detail 
 that I might not ufe any w r ord not previoully 
 explained. 
 
 The potalh obtained by this procefs is always 
 lefs or more faturated with carbonic acid, which 
 is eafily accounted for : As the potadr does not 
 form, or at leaft is not fet free, but in propor- 
 
 U tion 
 
i 5 4 ELEMENTS 
 
 tion as the charcoal of the vegetable is convert- 
 ed into carbonic acid by the addition of oxygen, 
 either from the air or the water, it follows, that 
 each particle of potafh, at the inflant of its for- 
 mation, or at lead of its liberation, is in contad 
 with a particle of carbonic acid, and, as there 
 is a confiderable affinity between thefe two fub- 
 ftances, they naturally combine together. Al- 
 though the carbonic acid has lefs affinity with 
 potafh than any other acid, yet it is difficult to 
 feparate the lafl portions from it. The mofl 
 ufual method of accompliffiing this is to diffolve 
 the potafh in water ; to this folution add two or 
 three times its weight of quicklime, then filtrate 
 the liquor and evaporate it in clofe veffels; the 
 faline fubftance left by the evaporation is pot- 
 afh almoft entirely deprived of carbonic acid. 
 In this ftate it is foluble in an equal weight of 
 water, and even attrads the moiflure of the air 
 with great avidity ; by this property it furnifhes 
 us with an excellent means of rendering air or 
 gas dry by expofing them to its adion. In this 
 ftate it is foluble in alkohol, though not when 
 combined with carbonic acid; and Mr Berthollet 
 employs this property as a method of procuring 
 potafh in the ftate of perfed purity. 
 
 All vegetables yield lefs or more of potafh in 
 confequence of combuftion, but it is furnifhed 
 in various degrees of purity by different vege- 
 tables; ufually, indeed, from all of them it is 
 
 mixed 
 
OF CHEMISTRY. 
 
 *55 
 
 mixed with different falts from which it is eafily 
 feparable. We can hardly entertain a doubt 
 that the afhes, or earth which is left by vege- 
 tables in combuftion, pre-exifted in them before 
 they were burnt, forming what may be called 
 the fkeleton, or offeous part of the vegetable. 
 But it is quite otherwife with potafh ; this fub- 
 ftance has never yet been procured from vege- 
 tables but by means of proceffes or intermedia 
 capable of furnifhing oxygen and azote, fuch 
 as combuftion, or by means of nitric acid ; fo 
 that it is not yet demonftrated that potafh may 
 not be a produce from thefe operations. I have 
 begun a feries of experiments upon this object, 
 and hope foon to be able to give an account of 
 their refults. 
 
 § 2. Of Soda. 
 
 Soda, like potafh, is an alkali procured by 
 lixiviation from the allies of burnt plants, but 
 only from thofe which grow upon the fea-fide, 
 and efpecially from the herb kali , whence is de- 
 rived the name alkali , given to this fubftance by 
 the Arabians. It has fome properties in com- 
 mon with potafh, and others which are entirely 
 different : In general, thefe two fubftances have 
 peculiar characters in their faline combinations 
 which are proper to each, and confequently 
 diftinguifh them from each other 5 thus foda, 
 
 which. 
 
ELEMENTS 
 
 L5S 
 
 which, as obtained from marine plants, is ufu- 
 aily entirely faturated with carbonic acid, does 
 not attraft the humidity of the atmofphere like 
 potafh, but, on the contrary, deficcates, its crif- 
 tals efflorefce, and are converted into a white 
 powder having all the properties of foda, which 
 it really is, having only loft its water of criftal- 
 lization. 
 
 Hitherto we are not better acquainted with 
 the conftituent' elements of foda than with thofe 
 of potalh, being equally uncertain whether it 
 previoufly exifted ready formed in the vegetable 
 or is a combination of elements effe&ed by com- 
 buftion. Analogy leads us to fufpcft that azote 
 is a conftituent element of all the alkalies, as is 
 the cafe with ammoniac ; but we have only flight 
 prefumptions, unconfirmed by any decifive ex- 
 periments, refpedting the compofition of potafh 
 and foda. 
 
 § 3. Of Ammoniac . 
 
 We have, however, very accurate knowledge 
 of the compofition of ammoniac, or volatile al- 
 kali, as it is called by the old chemifts. Mr 
 Berthollet, in the Memoirs of the Academy for 
 1784, p. 316. has proved by analyfts, that 1000 
 parts of this fubftance confift of about 8 07 parts 
 of azote combined with 193 parts of hydrogen. 
 
 Ammoniac 
 
OF CHEMISTRY. 
 
 *57 
 
 Ammoniac is chiefly procurable from animal 
 fubftances by diftillation, during which procefs 
 the azote and hydrogen neceflary to its forma- 
 tion unite in proper proportions ; it is not, how« 
 ever, procured pure by this procefs, being mix- 
 ed with oil and water, and moftly faturated with 
 carbonic acid. To feparate thefe fubftances it 
 is firft combined with an acid, the muriatic for 
 inftance, and then difengaged from that com- 
 bination by the addition of lime or potafli. 
 When ammoniac is thus produced in its great- 
 eft degree of purity it can only exift under the 
 gafleous form, at leaft in the ufual temperature 
 of the atmofphere, it has an exceflively pene- 
 trating finell, is abforbed in large quantities by 
 water, efpecially if cold and aflifted by compref* 
 fion. Water thus faturated with ammoniac has 
 ufually been termed volatile alkaline fluor ; we 
 fhall call it either Amply ammoniac, or liquid 
 ammoniac, and ammoniacal gas when it exifts 
 in the aeriform ftate. 
 
 §4 -Of Lime , Magnefia , Barytes , and ArgilL 
 
 The compofition of thefe four earths is total- 
 ly unknown, and, until by new difcoveries their 
 conftituent elements are afcertained, we are cer- 
 tainly authorifed to confider them as Ample 
 bodies. Art has no lhare in the produ&ion of 
 thefe earths, as they are all procured ready form- 
 ed 
 
1 58 ELEMENTS 
 
 ed from nature ; but, as they have all, efpecially 
 the three firft, great tendency to combination, 
 they are never found pure. Lime is ufually fa- 
 turated with carbonic acid in the ftate of chalk, 
 calcarious fpars, moll: of the marbles, &c. ; 
 fometimes with fulphuric acid, as in gypfum 
 and plafter Hones ; at other times with fluoric 
 acid forming vitreous or fluor fpars ; and, laft- 
 Iv, it is found in the waters of the fea, and of 
 Saline fprings, combined with muriatic acid. Of 
 « all the falifiable bafes it is the mod universally 
 Spread through nature. 
 
 Magnefia is found in mineral waters, for the 
 molt part combined with fulphuric acid ; it is 
 likewife abundant in fea-water, united with mu- 
 riatic acid ; and it exifts in a great number of 
 Hones of different kinds. 
 
 Barytes is much lefs common than the three 
 preceding earths ; it is found in the mineral 
 kingdom, combined with fulphuric acid, form- 
 ing heavy fpars, and fometimes, though rarely, 
 united to carbonic acid. 
 
 Argill, or the bafe of alum, having lefs ten- 
 dency to combination than the other earths, is 
 often found in the ftate of argill, uncombined 
 with any acid. It is chiefly procurable from 
 clays, of which, properly fpeaking, it is the bafe, 
 or chief ingredient. 
 
 $S‘Of 
 
OF CHEMISTRY. 
 
 *59 
 
 §5. Of Metallic Bodies . 
 
 The metals, except gold, and fometimes (li- 
 ver, are rarely found in the mineral kingdom in 
 their metallic (tate, being ufually lefs or more 
 faturated with oxygen, or combined with ful- 
 phur, arfenic, fulphuric acid, muriatic acid, car- 
 bonic acid, or phofphoric acid. Metallurgy, or 
 the docimaftic art, teaches the means of fepa- 
 rating them from thefe foreign matters \ and 
 for this purpofe we refer to fuch chemical books 
 as treat upon thefe operations. 
 
 We are probably only acquainted as yet with 
 a part of the metallic fubftances exifting in na- 
 ture, as all thofe which have a ftronger affinity 
 to oxygen, than charcoal poflefles, are incapable 
 of being reduced to the metallic (late, and, con- 
 fequently, being only prefented to our obferva- 
 tion under the form of oxyds, are confounded 
 with earths. It is extremely probable that ba- 
 rytes, which we have juft now arranged with 
 earths, is in this fituation ; for in many experi- 
 ments it exhibits properties nearly approaching 
 to thofe of metallic bodies. It is even poffible 
 that all the fubftances we call earths may be 
 only metallic oxyds, irreducible by any hitherto 
 known procefs. 
 
 Thofe metallic bodies we are at prefent ac- 
 quainted with, and which we can reduce to the- 
 
 metallic 
 
i6o ELEMENTS 
 metallic or reguline ftate, are the following fe* 
 
 venteen : 
 
 1. Arfenic. 
 
 2. Molybdena. 
 
 3. Tungftein. 
 
 4. Manganefe. 
 
 5. Nickel. 
 
 6. Cobalt. 
 
 7. Bifmuth. 
 
 8. Antimony. 
 
 9. Zinc. 
 
 10. Iron. 
 
 1 1. Tin. 
 
 12. Lead. 
 
 13. Copper. 
 
 14. Mercury. 
 
 15. Silver. 
 
 16. Platina. 
 
 17. Gold. 
 
 I only mean to confider thefe as falifiable 
 bafes, without entering at all upon the confide- 
 ration of their properties in the arts, and for 
 the ufes of fociety. In thefe points of view each 
 metal would require a complete treatife, which 
 would lead me far beyond the bounds I have 
 prefcribed for this work. 
 
 CHAP. 
 
OF CHEMISTRY, 
 
 i6i 
 
 CHAP. XVII. 
 
 i Continuation of the Obfervations upon Salifiable 
 Bafesy and the Formation of Neutral Salts . 
 
 T T is neceffary to remark, that earths and al- 
 *“* kalies unite with acids to form neutral falts 
 -without the intervention of any medium, where- 
 as metallic fubftances are incapable of forming 
 this combination without being previoufly lefs 
 or more oxygenated ; ftridly fpeaking, there- 
 fore, metals are not foluble in acids, but only 
 metallic oxyds. Hence, when we put a metai 
 into an acid for folution, it is neceffary, in the 
 frrff place, that it become oxygenated, either by 
 attrading oxygen from the acid or from the 
 water ; or, in other words, that a metal cannot 
 be diffolved in an acid unlefs the oxygen, either 
 of the acid, or of the water mixed with it, has 
 a ftronger affinity to the metal than to the hy- 
 drogen or the acidifiable bafe ; or, what a- 
 mounts to the fame thing, that no metallic fo- 
 lution can take place without a previous de- 
 compofition of the water, or the acid in which 
 it is made. The explanation of the principal 
 phenomena of metallic folution depends entire- 
 
 X ly 
 
2(52 
 
 ELEMENTS 
 
 ly upon this fimple observation, which was 
 overlooked even by the iliuftrious Bergman. 
 
 The firft and moft ftriking of thefe is the ef- 
 fervefcence, or, to fpeak lefs equivocally, the 
 difengagement of gas which takes place during 
 the folution ; in the folutions made in nitric 
 acid this effervefcence is produced by the difen- 
 gagement of nitrous gas ; in folutions with ful- 
 phuric acid it is either fulphurous acid gas or 
 hydrogen gas, according as the oxydation of 
 the metal happens to be made at the expence 
 of the fulphuric acid or of the w r ater. As both 
 nitric acid and water are compofed of elements 
 which, when feparate, can only exift in the gaf- 
 feous form, at lea ft in the common temperature of 
 the atmofphere, it is evident that, whenever either 
 of thefe is deprived of its oxygen, the remain- 
 ing element mull inftantly expand and afiume 
 the (late of gas ; the effervefcence is occasioned 
 by this fudden converfion from the liquid to the 
 gaffeous ftate. The fame decompofition, and 
 confequent formation of gas, takes place when 
 folutions of metals are made in fulphuric acid : 
 In general, efpecially by the humid way, metals 
 do not attract all the oxygen it contains ; they 
 therefore reduce it, not into fulphur, but into ful- 
 phurous acid, and as this acid can only exift as 
 gas in the ufual temperature, it is difengaged, 
 and occafions effervefcence. 
 
 The 
 
OF CHEMISTRY. 
 
 163 
 
 The fecond phenomenon is, that, when the 
 metals have been previoufly oxydated, they all 
 diffolve in acids without effervefcence : This is 
 eafily explained ; becaufe, not having now any 
 occafion for combining with oxygen, they nei- 
 ther decorrtpofe the acid nor the water by which, 
 in the former cafe, the effervefcence is occasion- 
 ed. 
 
 A third phenomenon, which requires parti- 
 cular confideration, is, that none of the metals 
 produce effervefcence by folution in oxygenated 
 muriatic acid. During this procefs the metal, 
 in the firft place, carries off the excefs of oxy- 
 gen from the oygenated muriatic acid, by which 
 it becomes oxydated, and reduces the acid to 
 the ftate of ordinary muriatic acid. In this cafe 
 there is no produ&ion of gas, not that the mu- 
 riatic acid does not tend to exift in the gafleous 
 ftate in the common temperature, which it does 
 equally with the acids formerly mentioned, but 
 becaufe this acid, which otherwife would ex- 
 pand into gas, finds more water combined with 
 the oxygenated muriatic acid than is neceffary 
 to retain it in the liquid form ; hence it does 
 not difengage like the fulphurous acid, but re- 
 mains, and quietly dilTolves and combines with 
 the metallic oxyd previoufly formed from its fa- 
 perabundant oxygen. 
 
 The fourth phenomenon is, that metals are 
 absolutely infoluble in fuch acids as have their 
 
 bales 
 
ELEMENTS 
 
 bales joined *o oxygen by a dronger affinity than 
 thefe metals are capable of exerting upon that 
 acidifying principle. Hence filver, mercury, 
 and lead, in their metallic dates, are infoluble 
 in muriatic acid, but, when previoufly oxy dated, 
 they become readily foluble without effervef* 
 cence. 
 
 From thefe phenomena it appears that oxy- 
 gen is the bond of union between metals and 
 acids ; and from this we are led to fuppofe that 
 oxygen is contained in all fubdances which have 
 a drong affinity with acids : Hence it is very 
 probable the four eminently falidable earths 
 contain oxygen, and their capability of unit- 
 ing with acids is produced by the intermedi- 
 ation of that element. What I have formerly 
 noticed relative to thefe earths is confiderably 
 drengthened by the above confiderations, viz. 
 that they may very poffibiy be metallic oxyds, 
 with which oxygen has a dronger affinity than 
 with charcoal, and confequently not reducible 
 by any known means. 
 
 Ail the acids hitherto known are enumerated 
 in the following table, 'the fird column of which 
 contains the names of the acids according to the 
 new nomenclature, and in the fecond column 
 are placed the bafes or radicals of thefe acids, 
 with obfervations. 
 
 \ ' 
 
 Names 
 
OF CHEMISTRY. 165 
 
 Names of the Acids . 
 
 Names of the Bafesy *wtth Obfervations* 
 
 1. Sulphurous 
 
 2. Sulphuric 
 
 3. Phofphorous 
 
 4. Phofphoric 
 
 5. Muriatic 
 
 6. Oxygenated muriatic 
 
 7. Nitrous 
 *8. Nitric 
 
 9. Oxygenated nitric 
 
 10. Carbonic 
 
 1 1. Acetous 
 
 12. Acetic 
 
 13. Oxalic 
 
 14. Tartarous 
 
 15. Pyro-tartarous 
 
 16. Citric 
 
 17. Malic 
 
 18. Pyro-lignous 
 
 19. Pyro-mucous 
 
 20. Gallic 
 
 21. Pruffic 
 
 22. Benzoic 
 
 23. Succinic 
 
 24. Camphoric 
 
 25. Ladfic 
 
 26. Sacchodadlic 
 
 27. Bombic 
 
 28. Formic 
 
 29. Sebacic 
 
 30. Boracic 
 
 31. Fluoric 
 
 32. Antimonic 
 
 33. Argentic 
 
 34. Arleniac * 
 
 } 
 
 Sulphur. 
 
 ^ Phofphorus. 
 
 7 Muriatic radical or bafe, hitherto un« 
 5 known. 
 
 ^ Azote. 
 
 Charcoal 
 
 The bafes or radicals of all thefe a- 
 cids feem to be formed by a combi- 
 nation of charcoal and hydrogen ; 
 and the only difference feems to be 
 owing to the different proportions in 
 } which thefe elements combine to form 
 their bafes, and to the different dofes 
 of oxygen in their acidification. A 
 connected feries of accurate experi- 
 ments is hill wanted upon this fub- 
 
 J je£h 
 
 *! Our knowledge of the bafes of 
 thefe acids is hitherto imperfedt ; we 
 ! only know that they contain hydro- 
 " gen and charcoal as principal ele- 
 ments, and that the pruffic acid con- 
 tains azote. 
 
 i 
 
 The bafe of thefe and all the acids 
 procured from animal fubftancesfeems 
 to conlift of charcoal, hydrogen, 
 phofphorus, and azote. 
 
 The bafes of thefe two are hitherto 
 entirely unknown. 
 
 Antimony. 
 
 Silver, 
 
 Arfenic. Names 
 
 * This term fwerves a little fiom the rule in making the 
 name of this acid terminate in ac inftead of ic. The bafe and 
 
 acid are diftinguifhed in French by arfenic and arfenique ; but, 
 having chofen the Englifh termination ic to tranflate the French 
 iqtte, I was obliged to ufe this fmall deviation. — E, 
 
i66 ELEMENTS 
 
 Names of the Acids . 
 
 Names of the Bafes . 
 
 35. Bifmuthic 
 
 Bifmuth. 
 
 36. Cobaltic 
 
 Cobart. 
 
 37. Cupric 
 
 Copper. 
 
 38. Stannic 
 
 Tin. 
 
 39. Ferric 
 
 Iron. 
 
 40. Munganic 
 
 Manganefe. 
 
 41. Mercuric * 
 
 Mercury. 
 
 42. Molybdic 
 
 Molybdena, 
 
 43. Nickolic 
 
 Nickel, 
 
 44. Auric 
 
 Gold. 
 
 45. Platinic 
 
 Platina. 
 
 46. Plumbic 
 
 Lead. 
 
 47. Tungftic 
 
 Tungftein. 
 
 48. Zincic 
 
 Zinc. 
 
 In this lift, which contains 48 acids, I have 
 enumerated 17 metallic acids hitherto very im- 
 perfe£tly known, but upon which Mr Berthollet 
 is about to publifh a very important work. It 
 cannot be pretended^ that all the acids which 
 exift in nature, or jrather all the acidifiable ba- 
 les, are yet discovered ; but, on the other hand, 
 there are confiderable grounds for fuppofing that 
 a more accurate inveftigation than has hitherto 
 been attempted will dimimfh the number of the 
 vegetable acids, by ihowing that Several of theSe, 
 at prefent considered as diftind acids, are only 
 
 modi- 
 
 * Mr Lavoifier has hydrargirique ; but mercurius 
 being ufed Sor the bate or metal, the name of the acid, 
 as above, is equally regular, and lefs harik— E. 
 
OF CHEMISTRY, i 6 7 
 
 modifications of others. All that can be done 
 in the prefent ftate of our knowledge is, to give 
 a view of chemiftry as it really is, and to efta- 
 blifh fundamental principles, by which fuch bo- 
 dies as may be difcovered in future may re- 
 ceive names, in conformity with one uniform 
 fyftem. 
 
 The known falifiable bafes, or fubftances ca- 
 pable of being converted into neutral falts by 
 union with acids, amount to 24 ; viz. 3 alkalies, 
 4 earths, and 1 7 metallic fubftances ; fo that, 
 in the prefent ftate of chemical knowledge, the 
 whole poftible number of neutral falts amounts 
 to 1152 *. This number is upon the fuppofi- 
 tion that the metallic acids are capable of dif- 
 folving other metals, which is a new branch of 
 chemiftry not hitherto inveftigated, upon which 
 depends all the metallic combinations named 
 vitreous . There is reafon to believe that many 
 of thefe fuppofable faline combinations are not 
 capable of being formed, which rauft greatly 
 reduce the real number of neutral falts produ- 
 cible by nature and art. Even if we fuppofe 
 the real number to amount only to five or fix 
 hundred fpecies of poftible neutral falts, it is e- 
 yident that, were we to diftinguifh them, after 
 
 the 
 
 * This number excludes all triple falts, or fuch as 
 contain more than one falifiable bafe, all the falts whofe 
 bafes are over or under faturated with acid, and thofe 
 formed by the nitro-muriatic acid.— E. 
 
ELEMENTS 
 
 16S 
 
 the manner of the ancients, either by the names 
 of their firfl difcoverers, or by terms derived 
 from the fubftances from which they are procu- 
 red, we fhould at iaft have fuch a confufion of 
 arbitrary defignations, as no memory could pof- 
 fibly retain. This method might be tolerable 
 in the early ages of chemiftry, or even till with- 
 in thefe twenty years, when only about thirty 
 fpecies of falts were known ; but, in the prefent 
 times, when the number is augmenting daily, 
 when every new acid gives us 24 or 48 new 
 falts, according as it is capable of one or two 
 degrees of oxygenation, a new method is cer- 
 tainly neceffary. The method we have adopted, 
 drawn from the nomenclature of the acids, is 
 perfectly analogical, and, following nature in 
 the fimplicity of her operations, gives a natural 
 and eafy nomenclature applicable to every pof- 
 fible neutral fait. 
 
 In giving names to the different acids, we ex- 
 prefs the common property by the generical 
 term add , and diftinguifh each fpecies by the 
 name of its peculiar acidifiable bafe. Hence 
 the acids formed by the oxygenation of fulphur, 
 phofphorus, charcoal, &c. are called fulphuric 
 add, phofphoric add , car bonk add , &c. We 
 thought it likewife proper to indicate the differ- 
 ent degrees of faturation with oxygen, by differ- 
 ent terminations of the fame fpecific names. 
 
 Hence 
 
OF CHEMISTRY. 169 
 
 Hence we diftinguifh between fulphurous and 
 fulphuric, and between phofphorous and phof- 
 phoric acids, &c. 
 
 By applying thefe principles to the nomen- 
 clature of neutral falts, we give a common term 
 to all the neutral falts arifing from the combi- 
 nation of one acid, and diftinguifh the fpecies 
 by adding the name of the falifiable bafe. Thus, 
 all the neutral falts having fulphuric acid in 
 their compofition are named fulpkats ; thofe 
 formed by the phofphoric acid, phofphats , &c. 
 The fpecies being diflinguifhed by the names of 
 the falifiable bafes gives us fulphat of potafhy fuU 
 phat of foda , fulphat of ammoniac , fulphat of limey 
 fulphat of iron 9 &c. As we are acquainted 
 with 24 falifiable bafes, alkaline, earthy, and 
 metallic, we have confequently 24 fulphats, as 
 many phofphats, and fo on through all the a- 
 cids. Sulphur is, however, fufceptible of two 
 degrees of oxygenation, the firft of which pro- 
 duces fulphurous, and the fecond, fulphuric a- 
 cid ; and, as the neutral falts produced by thefe 
 two acids, have different properties, and are 
 in fa£t different falts, it becomes neceffary to di- 
 flinguifh thefe by peculiar terminations ; w r e 
 have therefore diflinguifhed the neutral falts 
 formed by the acids in the firft or leffer degree 
 of oxygenation, by changing the termination at 
 into ite^ as fulphites , phofphites *, &c. Thus, oxy- 
 Y genated 
 
 # As all the fpecific names of the acids in the new 
 
 comen* 
 
ELEMENTS 
 
 1 70 
 
 genated or acidified fulphur, in its two degrees 
 of oxygenation is capable of forming 48 neu- 
 tral falts, 24 of which are fulphites, and as ma- 
 ny fulphats ; which is likewife the cafe with all 
 the acids capable of two degrees of oxygena- 
 tion *. 
 
 It were both tirefome and unneceffary to fol- 
 low thefe denominations through all the varie- 
 ties of their poflible application ; it is enough 
 to have given the method of naming the various 
 falts, which, when once well underflood, is ea- 
 fily applied to every poffible combination. The 
 name of the combuflible and acidifiable body 
 being once known, the names of the acid it is 
 capable of forming, and of all the neutral com- 
 binations 
 
 nomenclature are adjectives, they would have applied 
 feverally to the various falifiabie bafes, without the in- 
 vention of other terms, with perfect diftinCtnefs. Thus, 
 fulphurous potajhy and fulphuric potajh , are equally diftinCt 
 as fulphite of potajh , and fulphat of potajh ; and have the 
 advantage of being more eafily retained in the memo- 
 ry, becaufe more naturally arifnfg from the acids them- 
 felves, than the arbitrary terminations adopted by Mr 
 Lavoifier.— -E. 
 
 # There is yet a third degree of oxygenation of a- 
 cids, as the oxygenated muriatic and oxygenated nitric 
 acids. The terms applicable to the neutral falts refult- 
 ing from the union of thefe acids -with falifiabie bafes 
 is fupplied by the Author in the Second Part of this 
 Work Thefe are formed by prefixing the word oxyge- 
 
 - ,'td to the name of the fait produced by the fecond 
 
 - v of oxygenation. Thus, oxygenated mUriat of po- 
 
 oxygenated nitrat offoda, &c. — E. 
 
OF CHEMISTRY. 
 
 171 
 
 binations the acid is fufceptible of entering in- 
 to, are moll readily remembered. Such as re- 
 quire a more complete illudration of the me- 
 thods in which the new nomenclature is applied 
 will, in the Second Part of this book, find 
 Tables which contain a full enumeration of all 
 the neutral falts, and, in general, all the pof- 
 fible chemical combinations, fo far as is con- 
 fident with the prefent date of our knowledge. 
 To thefe I {hall fubjoin fhort explanations, con- 
 taining the bed and mod fimple means of pro- 
 curing the different fpecies of acids, and fome 
 account of the general properties of the neutral 
 falts they produce. 
 
 I fhall not deny, that, to render this work 
 more complete, it would have been neceffary to 
 add particular obfervatior.s upon each fpecies of 
 fait, its folubility in water and alkohol, the pro- 
 portions of acid and of falifiable bafe in its 
 compofition, the quantity of its water of crif- 
 tallization, the different degrees of faturation 
 it is fufceptible of, and, finally, the degree 
 of force or affinity with which the acid ad- 
 heres to the bafe. This immenfe work has been 
 already begun by Meffrs Bergman, Morveau, 
 Kirwan, and other celebrated chemids, but is 
 hitherto only in a moderate date of advance- 
 ment, even the principles upon which it is 
 founded are not perhaps fufficiently accurate. 
 
 Thefe 
 
z 7 2 ELEMENTS 
 
 Thefe numerous details would have fweiled 
 this elementary treatife to much too great a 
 fize ; befides that, to have gathered the necef- 
 fary materials, and to have completed all the 
 feries of experiments requifite, mufl have re- 
 tarded the publication of this book for many 
 years. This is a vaft field for employing the 
 zeal and abilities of young chemifts, whom I 
 would advife to endeavour rather to do well 
 than to do much, and to ascertain, in the firft 
 place, the compofition of the acids, before en- 
 tering upon that of the neutral falts 3 Every e- 
 cifice which is intended to refift the ravages of 
 time fhould be built upon a lure foundation ; 
 and, in the prefent flateof chemiflry, to attempt 
 difcoveries by experiments, either not perfectly 
 exact, r 'or not fufficiently rigorous, will ferve 
 only to interrupt its progrefs, inftead of contri- 
 buting to its advancement. 
 
 PART 
 
OF CHEMISTRY. 17$ 
 
 PART II. 
 
 Of the Combination of Acids with 
 Salifiable Bafes, and of the For- 
 mation of Neutral Salts. 
 
 INTRODUCTION. 
 
 I F I had ftri&ly followed the plan I at firft 
 laid down for the conduft of this work, I 
 would have confined myfelf, in the Tables and 
 accompanying obfervations which compofe this 
 Second Part, to fhort definitions of the feveral 
 known acids, and abridged accounts of the pro- 
 cefles by which they are obtainable, with a mere 
 nomenclature or enumeration of the neutral 
 falts which refult from the combination of thefe 
 acids with the various falifiable bafes. But I 
 afterwards found that the addition of fimilar 
 Tables of all the fimple fubftances which enter 
 
 into 
 
*74 E L E M E N T S 
 
 into the compofition of the acids and oxyds, 
 together with the various poffible combinations 
 of thefe elements, would add greatly to the uti- 
 lity of this work, without being any great in- 
 creafe to its fize. Thefe additions, which are 
 all contained in the twelve firft fe&ions of this 
 Part, and the Tables annexed to thefe, form a 
 kind of recapitulation of the firft fifteen Chap- 
 ters of the Firft Part : The reft of the Tables 
 and Sections contain all the faline combina- 
 tions. 
 
 It muft be very apparent that, in this Part of 
 the Work, I have borrowed greatly from what 
 has been already publifhed by Mr de Morveau 
 in the Firft Volume of the Encyclopedie par ordre 
 des Matures. I could hardly have difcovered 
 a better fource of information, efpecially when 
 the difficulty of confulting books in foreign 
 languages is confidered. I make this general 
 acknowledgment on purpofe to fave the trouble 
 of references to Mr de Morveau’s work in the 
 courfe of the following part of mine. 
 
 Table 
 
OF CHEMISTRY. i i'?$ 
 
 TABLE OF SIMPLE SUBSTANCES. 
 
 Simple fubftances belonging to all the kingdoms of na- 
 ture, which may be considered as the elements of bo- 
 dies. 
 
 New Names* 
 
 Light 
 
 Caloric 
 
 Oxygen 
 
 Azote 
 
 Hydrogen 
 
 i 
 
 Correfpondesit old Names . 
 Light. 
 
 Heat. 
 
 Principle or element of heat. 
 Fire. Igneous fluid. 
 
 Matter of fire and of heat. 
 Dephlogifticated air. 
 
 Empyreal air. 
 
 Vital air, or 
 Bafe of vital air. 
 
 Phlogifticated air or gas. 
 Mephitis, or its bafe. 
 Inflammable air or gas, 
 or the bafe of inflammable air* 
 
 Oxydable and Acidifiable Ample Subftances not Metallic. 
 New Names . Correfpondent old names . 
 
 Sulphur 
 Phofphorus 
 Charcoal 
 Muriatic radical 
 Fluoric radical 
 Boracic radical 
 
 The fame names. 
 
 Still unknown. 
 
 Oxydable and Acidifiable Ample Metallic Bodies. 
 New Names . Correfpondent Old Names* 
 
 Antimony 
 
 Arfenic 
 
 
 ' Antimony. 
 Arfenic. 
 
 Bifmuth 
 
 
 Bifmuth. 
 
 Cobalt 
 
 
 Cobalt. 
 
 Copper 
 Gold * 
 
 
 Copper. 
 
 Gold. 
 
 Iron - 
 
 O 
 
 Iron. 
 
 Lead - 
 
 
 Lead. 
 
 Manganefe 
 Mercury 
 Molybdena 
 Nickel - 
 
 <D 
 
 | Manganefe* 
 Mercury. 
 Molybdena. 
 Nickel. 
 
 Platina 
 
 
 Platina. 
 
 Silver 
 
 
 Silver. 
 
 Tin 
 
 
 Tin. 
 
 Tungllein 
 
 Zinc 
 
 
 Tungftein. 
 
 ^Zinc. 
 
 Salifiable 
 
i;6 ELEMENTS 
 
 Salifiable firople Earthy Subftances. 
 
 New Names . 
 Lime 
 
 Magnefia 
 
 Barytes 
 
 Argill 
 
 Silex 
 
 Correjpondent old Names. 
 
 C Chalk, calcareous earth. 
 
 £ Quicklime. 
 
 C Magnefia, bafe of Epfom fait. 
 £ Calcined or cauftic magnefia. 
 Barytes, or heavy earth. 
 Clay, earth of alum. 
 
 Siliceous or verifiable earth. 
 
 Sect. I . — Observations upon the Table of Simple 
 Sub/lances. 
 
 The principle objeft of chemical experi- 
 ments is to decompofe natural bodies, fo as fepa- 
 rately to examine the different fubftances which 
 enter into their compofition. By confulting 
 chemical fyftems, it will be found that this fci- 
 ence of chemical analyfis has made rapid pro- 
 grefs in our own times. Formerly oil and fait 
 were confidered as elements of bodies, whereas 
 later obfervation and experiment have fhown 
 that all falts, inftead of being fimple, are com- 
 pofed of an acid united to a bafe. The bounds 
 of analyfis have been greatly enlarged by mo- 
 dern difcoveries * ; the acids are fhown to be 
 compofed of oxygen, as an acidifying principle 
 common to all, united in each to a particular 
 bafe. 1 have proved what Mr Haffenfratz had 
 
 before 
 
 * See Memoirs of the Academy for 1 776, p.6ji. 
 and for 1778, p. 535. — A. 
 
OF CHEMISTRY. 177 
 
 before advanced, that thefe radicals of the acids 
 are not all fimple elements, many of them 
 being, like the oily principle, compofed of hy- 
 drogen and charcoal. Even the bafes of neu- 
 tral falts have been proved by Mr Berthollet to 
 be compounds, as he has fhown that ammoniac 
 is compofed of azote and hydrogen. 
 
 Thus, as chemiftry advances towards perfec- 
 tion, by dividing and fubdividing, it is impof- 
 fible to fay where it is to end ; and thefe things 
 we at prefent fuppofe fimple may foon be found 
 quite otherwife. All we dare venture to affirm 
 of any fubftance is, that it mu ft be confidered 
 as fimple in the prefent (late of our knowledge, 
 and fo far as chemical analyfis has hitherto been 
 able toffiow. We may even prefume that the earths 
 mufl foon ceafe to be confidered'as fimple bodies; 
 they are the only bodies of the falifiable clafs 
 which have no tendency to unite with oxygen ; 
 and I am much inclined to believe that this pro- 
 ceeds from their being already faturated with 
 that element. If fo, they will fall to be confi- 
 dered as compounds confiding of fimple fub- 
 flances, perhaps metallic, oxydated to a certain 
 degree. This is only hazarded as a conjec- 
 ture ; and I trull the reader will take care not 
 to confound what I have related as truths, fixed 
 on the firm bafis of obfervation and experi- 
 ment, with mere hypothetical conjeflures. 
 
 Z 
 
 The 
 
178 ELEMENTS 
 
 . 
 
 The fixed alkalies, potafh, and foda, are o- 
 mitted in the foregoing Table, becaufe they 
 are evidently compound fubftances, though we 
 are ignorant as yet what are the elements they 
 are compofed of. 
 
 TaBX-E 
 
OF CHEMISTRY, 
 
 *70 
 
 Table of compound oxydable and acidifiable bafes . 
 
 Oxydable or acidifiable 
 bafe, from the mineral 
 kingdom. 
 
 Oxydable or acidifiable 
 hydro - carbonous or 
 carbono-hydrous radi- 
 cals from the vegetable 
 kingdom. 
 
 Oxydable or acidifiable 
 radicals from the ani- 
 mal kingdom, which 
 moftly contain azote, 
 and frequently phof- 
 phorus. 
 
 Names of the radicals. 
 
 f Nitro-muriatic radical or 
 2 bafe of the acid formerly 
 £ called aqua regia. 
 pTartarous radical or bafe. 
 
 | Malic. 
 
 Citric. 
 
 Pyro-lignous. 
 
 Pyro-mucous. 
 
 Pyro-tartarous. 
 
 Oxalic. 
 
 Acetous. 
 
 Succinic. 
 
 Benzoic, 
 
 Camphoric. 
 
 Gallic. 
 
 ""Lactic. 
 
 Sacchola&ic. 
 
 Formic. 
 
 Bombic. 
 
 Sebacic. 
 
 Lithic. 
 
 Pruflic, 
 
 Sect, 
 
 * Note .— — The radicals from the vegetable king* 
 dom are converted by a firft degree of oxygenation in- 
 to vegetable oxyds, fuch as fugar, ftarch, and gum or 
 mucus : Thofe of the animal kingdom by the fame 
 means form animal oxyds ; as lymph, A. 
 
 Radicals 
 
Sect. \h'*—Obfervatio??s upon the Table of ConU 
 pound Radicals . 
 
 The older chemifts being unacquainted with 
 the compofition of acids, and not fufpecling 
 them to be formed by a peculiar radical or bafe 
 for each, united to an acidifying principle or 
 element common to all, could not confequentiy 
 give any name to fubdances of which they had 
 not the mod didant idea. We had therefore 
 to invent a new nomenclature for this fubje<d, 
 though we were at the fame time fenfihie that 
 this nomenclature mud be fufceptible of great 
 modification when the nature of the compound 
 radicals fhall be better underdood *. 
 
 The compound oxydable and acidifiable ra- 
 dicals from the vegetable and animal kingdoms, 
 enumerated in the foregoing table, are not hi- 
 therto reducible to fyftematic nomenclature, be- 
 caufe their exaft analyfis is as yet unknown. 
 We only know in general, by fome experiments 
 of my own, and fome made by Mr Hafienfratz, 
 that mod of the vegetable acids, fucli as the 
 tartarous, oxalic, citric, malic, acetous, pyro- 
 tartarous, and pyromucous, have radicals com- 
 pofed of hydrogen and charcoal, combinecfm 
 
 fuoh 
 
 * See Part I. Chap. XI. upon this fubjett. — A* 
 
OF CHEMISTRY, 
 
 i8x 
 
 fuch a way as to form fingle bafes, and that 
 thefe acids only differ from each other by the 
 proportions in which thefe two fubflances enter 
 into the compofition of their bafes, and by the 
 degree of oxygenation which thefe bafes have 
 received. We know farther, chiefly from the 
 experiments of Mr Berthollet, that the radicals 
 from the animal kingdom, and even fome of 
 thofe from vegetables, are of a more compound 
 nature, and, befides hydrogen and charcoal, 
 that they often contain azote, and fometimes 
 phofphorus ; but we are not hitherto pofTeffed 
 of fufficiently accurate experiments for calcula- 
 ting the proportions of thefe feveral fubflances. 
 We are therefore forced, in the manner of the 
 older chemifts, (till to name thefe acids after the 
 fubflances from which they are procured. There 
 can be little doubt that thefe names will be laid 
 afide when our knowledge of thefe fubflances 
 becomes more accurate and extenfive ; the 
 terms hydro-carbonous , hydro-carbonic , carbono • 
 hydrous , and carbono-hydric *, will then become 
 fubflituted for thofe we now employ, which will 
 then only remain as teflimonies of the imperfect 
 flate in which this part of chemiflry was trans- 
 mitted to us by our predeceffors. 
 
 It 
 
 * See Part I. Chap. XI. upon the application of 
 thefe names according to the proportions of the two 
 ingredients. — A. 
 
ELEMENTS 
 
 i8z 
 
 It is evident that the oils, being compofed of 
 hydrogen and charcoal combined, are true car- 
 bono-hydrous or hydro-carbonous radicals $ 
 and, indeed, by adding oxygen, they are con- 
 vertible into vegetable oxyds and acids, accor- 
 ding to their degrees of oxygenation. We can- 
 not, however, affirm that oils enter in their en- 
 tire (late into the compofition of vegetable oxyds 
 and acids ; it is poffible that they previoufly lofe 
 a part either of their hydrogen or charcoal, and 
 that the remaining ingredients no longer exift 
 in the proportions neceflary to conftitute oils. 
 We ftill require farther experiments to elucidate 
 thefe points. 
 
 Properly fpeaking, we are only acquainted 
 with one compound radical from the mineral 
 kingdom, the nitro-muriatic, which is formed 
 by the combination of azote with the muriatic 
 radical. The other compound mineral acids 
 have been much lefs attended to, from their 
 producing lefs ftriking phenomena. 
 
 Sect. III. — Obfervations upon the Combinations of 
 
 Light and Caloric with different Sub/lances. 
 
 I have not conftru&ed any table of the com- 
 binations of light and caloric with the various 
 fimple and compound fubftances, becaufe our 
 conceptions of the nature of thefe combinations, 
 are not hitherto fufficiently accurate. We 
 
 know. 
 
OF CHEMISTRY. 
 
 183; 
 
 know, In general, that all bodies in nature are 
 imbued, furrounded, and penetrated in every- 
 way with caloric, which fills up every interval 
 left between their particles ; that, in certain 
 cafes, caloric becomes fixed in bodies, fo as to 
 conftitute a part even of their folid fubftance, 
 though it more frequently ads upon them with 
 a repulfive force, from which, or from its ac- 
 cumulation in bodies to a greater or Ielfer de- 
 gree, the transformation of folids into fluids, 
 and of fluids to aeriform elafticity, is entirely 
 owing. We have employed the generic name 
 gas to indicate this aeriform ftate of bodies pro- 
 duced by a fufficient accumulation of caloric ; 
 fo that, when we wifli to exprefs the aeriform 
 (late of muriatic acid, carbonic acid, hydrogen, 
 water, alkohol, &c. we do it by adding the word 
 gas to their names ; thus muriatic acid gas, 
 carbonic acid gas, hydrogen gas, aqueous gas, 
 alkoholic gas, &c. 
 
 The combinations of light, and its mode of 
 a&ing upon different bodies, is ftill lefs known. 
 By the experiments of Mr Berthollet, it appears 
 to have great affinity with oxygen, is fufceptible 
 of combining with it, and contributes alongft 
 with caloric to change it into the ftate of gas. 
 Experiments upon vegetation give reafon to be- 
 lieve that light combines with certain parts of 
 vegetables, and that the green of their leaves, 
 and the various colours of their flowers, is chief- 
 
 iy 
 
x3 4 ELEMENTS 
 
 ly owing to this combination. This much is 
 certain, that plants which grow in darknefs are 
 perfe&ly white, languid, and unhealthy, and 
 that to make them recover vigour, and to ac- 
 quire their natural colours, the direct influence 
 of light is abfolutely necefiary. Somewhat fimi- 
 lar takes place even upon animals : Mankind 
 degenerate to a certain degree when employed 
 in fedentary manufa&ures, or from living in 
 crowded houfes, or in the narrow lanes of large 
 cities ; whereas they improve in their nature 
 and conftitution in moft of the country labours 
 which are carried on in the open air. Organi- 
 zation, fenfation, fpontaneous motion, and all 
 the operations of life, only exift at the furface 
 of the earth, and in places expofed to the influ- 
 ence of light. Without it nature itfelf would 
 be lifeiefs and inanimate. By means of light, 
 the benevolence of the Deity hath filled the fur- 
 face of the earth with organization, fenfation, 
 and intelligence. The fable of Promotheus 
 might perhaps be confidered as giving a hint of 
 this philofophical truth, which had even prefent- 
 ed itfelf to the knowledge of the ancients. I 
 have intentionally avoided any difquifitions re- 
 lative to organized bodies in this work, for 
 which reafon the phenomena of refpiration, fan- 
 guification, and animal heat, are not confider- 
 ed ; but 1 hope, at fome future time, to be able 
 to elucidate thefe curious fubjefts. 
 
 Sect, 
 

 
 ► > 
 
 * 
 
 
 
To face Page 185. T A B L E of the binary Combinations of Oxygen with Ample Subftances. 
 
 
 Names ot the 
 Pimple Pub- 
 
 Firft degree of oxygenation. 
 
 Second degree 
 
 of oxygenation. 
 
 Third degn 
 
 ee of oxygenation. 
 
 Fourth degree of ox 
 
 ygenation. 
 
 
 fiances. 
 
 New Names. 
 
 | Ancient Names. 
 
 New Names. 
 
 [ Ancient Names. 
 
 | New Names. 
 
 Ancient Names. 
 
 New Names. 
 
 Ancient Names. 
 
 
 f Caloric . 
 
 
 
 
 
 
 
 
 
 
 
 j Oxygen gas . . . 
 
 ! air . . . S . . . 
 
 
 
 1 
 
 
 
 
 
 
 I Hydrogen . 
 
 1 Water *. 
 
 
 
 
 i 
 
 
 
 
 
 
 Azote . 
 
 > Nitrous oxyd, or baPe of 
 1 nitrous gas . . . 
 
 Nitrous gas or air . . 
 
 Nitrous acid . 
 
 Smoaking nitrous acid . j 
 
 | Nitric acid ; 
 
 
 Pale, or not fmoak- ' 
 ing nitrous acid . 
 
 Oxygenated nitric acid . . 
 
 Unknown 
 
 Combina- 
 tions of oxy- 
 gen with 
 Pimple non- 
 metallicfub- 
 
 Charcoal . 
 
 Oxyd of charcoal, or car- 
 
 Unknown .... 
 
 Carbonous acid . . . 
 
 Unknown . . . j 
 
 | Carbonic acid . 
 
 
 Fixed air . . . 
 
 Oxygenated carbonic acid 
 
 Unknown 
 
 Sulphur . . 
 Phcfphorus 
 
 Oxyd of fulphnr . . 
 
 Oxyd of phofphorus . . 
 
 Soft fuiphur .... 
 Refiduum from the com- 
 builion of phofphorus 
 
 Sulphurous acid 
 Phofphorous acid 
 
 Sulphureous acid . . | 
 
 Volatile acid of phofpho- ‘ 
 rus 
 
 Sulphuric acid • 
 Phofphoric acid . 
 
 
 Vitriolic acid . . 
 Phofphoric acid 
 
 Oxygenated fulphuric acid 
 Oxygenatedphofphoric acid 
 
 Unknown 
 
 Unknown 
 
 dances. 
 
 Muriatic ra 
 dical . . 
 
 Muriatic oxyd . . . 
 
 Unknown ...» 
 
 Muriatous acid . - . 
 
 Unknown .... 
 
 Muriatic acid . 
 
 
 Marine acid . . 
 
 Oxygenated muriatic acid . 
 
 Dephlogifticated 
 marine acid 
 
 
 Fluoric ra- 
 
 Fluoric oxyd . . . 
 
 Unknown .... 
 
 Fluorous acid . . 
 
 Unknown .... 
 
 Fluoric acid . 
 
 
 Unknown till lately 
 
 
 
 
 Boracic ra- 
 dical . . 
 
 Boracic oxyd . . . 
 
 Unknown .... 
 
 Boracons acid . . . 
 
 Unknown .... 
 
 Boracic acid . 
 
 
 Homberg’s fedative 
 [ fait ... . 
 
 
 
 
 Antimony . 
 
 Grey oxyd of antimony 
 
 Grey calx of antimony 
 
 White oxyd of antimony 
 
 White calx of antimony, 
 diaphoretic antimony 
 
 • Antimonic acid . 
 
 
 
 
 
 
 Silver . . 
 
 Oxyd of filver . . . 
 
 Calx of filver . . . 
 
 
 Argentic acid . 
 
 
 
 
 
 
 Arfenic . . 
 
 Grey oxyd of arfenic . 
 
 Grey calx of arfenic . 
 
 White oxyd of arfenic 
 
 White calx of arfenic . 
 
 Arfeniac acid . 
 
 
 Acid of arfenic . . 
 
 Oxygenated arfeniac acid 
 
 Unknown 
 
 
 Bifmuth . 
 
 Grey oxyd of bifmuth . 
 
 Grey calx of bifmuth . | 
 
 | White oxyd of bifmuth 
 
 
 White calx of bifmuth 
 
 Bifmuthic acid . 
 
 
 
 
 
 Cobalt . . 
 
 Grey oxyd of cobalt . 
 
 Grey calx of cobalt . j 
 
 
 Cobaltic acid 
 
 
 
 
 
 
 Copper . . 
 
 Brown oxyd of copper . 
 
 Brown calx of copper . * 
 
 : Blue and green oxyds of 
 [_ copper . . . • l 
 
 Blue and green calces of 
 
 Cupric acid 
 
 
 
 
 
 
 Tin . . 
 
 Grey oxyd of tin . . 
 
 Grey calx of tin . . | 
 
 | White oxyd of tin • . j 
 
 White calx of tin, or 
 putty of tin . 
 
 Stannic acid . 
 
 
 
 
 
 Combina- 
 
 Iron . . 
 
 Black oxyd of iron . 
 
 | Martial ethiops . . - 
 
 ^Yellow and red oxyds of* 
 
 ■ Ochre and ruft of iron . j 
 
 Ferric acid . 
 
 
 
 
 
 tions of oxy- 
 
 Manganefe 
 
 Black oxyd of manganefe | 
 
 j Black calx of manganefe 1 
 
 | Whiteoxyd of manganefe 
 
 | White calx of manganefe j 
 
 | Manganefic acid 
 
 
 
 
 
 gen with the 
 Pimple me- 
 
 Mercury . j 
 
 j Black oxyd of mercury 
 
 Ethiops mineral f . . - 
 
 [ Yellow and red oxyds of J 
 
 ^Turbith mineral, red pre ^ 
 c cipitate, calcined mer- s 
 
 - Mercuric acid . 
 
 
 
 
 
 tallic Pub- 
 
 
 L mercury • • . 
 
 [ cury, precipitate per fe\ 
 
 
 
 
 Oxygenated molybdic a-’ 
 cid 
 
 i 
 
 
 fiances. 
 
 Molybdena 
 
 Oxyd of molybdena . 
 
 Calx of molybdena . . 
 
 
 
 Molybdic acid . 
 
 * t 
 
 j Acid of molybdena - 
 
 Unknown 
 
 
 Nickel . . 
 
 Oxyd of nickel . . . 
 
 Calx of nickel . . . 
 
 
 C Red calx of gold, purple ‘ 
 l precipitate of caffius J 
 
 Nickelic acid . 
 
 
 
 j 
 
 
 Gold . . 
 
 Yellow oxyd of gold . 
 
 Yellow calx of gold . . 
 
 Red oxyd of gold . . • 
 
 Auric acid 
 
 
 
 
 
 
 Plat'ma . . 
 
 Yellow oxyd of platina 
 
 Yellow calx of platina . 
 
 Yellow and red oxyds of- 
 lead 1 
 
 Piatinic acid • 
 
 
 
 
 
 
 Lead . . 
 
 Grey oxyd of lead . . 
 
 Grey calx of lead . 
 
 | Mafficot and minium . 
 
 Plumbic acid 
 
 
 
 
 
 
 Tungilein . 
 
 Oxyd of Tungftein . . 
 
 Calx of Tungfiein . . - 
 
 : ; 
 
 | ...... . 
 
 Tungftic acid . 
 
 
 Acid of Tungftein ■ 
 
 Oxygenated Tungftic a-' 
 cid 
 
 Unknown 1 
 
 . 1 
 
 Zinc . . 
 
 Grey oxyd of zinc . . 
 
 Grey calx of zinc . 
 
 j White oxyd of zinc . . « 
 
 f White calx of zinc, pom- "j 
 [ pholix . . . 1 
 
 Zincic acid 
 
 
 
 
 
 
 
 • Only one degree of oxygenation of hydrogen is hitherto 
 
 known —A + Ethi 
 
 ops mineral is the fulphuret of m 
 
 ercury ; this ftiould have been called black precipitate of mercury.— E. 
 
 
OF CHEMISTRY. 
 
 185 
 
 Sect. IV- — Obfervations upon the Combinations 
 of Oxygen with the fimple Subftances. 
 
 Oxygen forms almofl a third of the mafs of 
 our atmofphere, and is confequently one of the 
 mod plentiful fubftances in nature. AW the 
 animals and vegetables live and grow in this 
 immenfe magazine of oxygen gas, and from it 
 we procure the greateft part of what we employ 
 in experiments. So great is the reciprocal af- 
 finity between this element and other fubftances, 
 that we cannot procure it difengaged from all 
 combination. In the atmofphere it is united 
 with caloric, in the date of oxygen gas, and 
 this again is mixed with about two thirds of its 
 weight of azotic gas. 
 
 Several conditions are requifite to enable a 
 body to become oxygenated, or to permit oxy- 
 gen to enter into combination with it. In the 
 tirft place, it is neceffary that the particles of the 
 body to be oxygenated fhall have lefs reciprocal 
 attra&ion with each other than they have for 
 the oxygen, which otherwife cannot poffibly 
 combine with them. Nature, in this cafe, may 
 be affifted by art, as we have it in our power to 
 diminifh the attradion of the particles of bodies 
 almofl at will by heating them, or, in other 
 words, by introducing caloric into the inter- 
 A a dices 
 
1 86 
 
 ELEMENTS 
 
 dices between their particles ; and, as the at- 
 traction of thefe particles for each other is di- 
 minifhed in the inverfe ratio of their diftance, it 
 is evident that there muft be a certain point of 
 diftance of particles when the affinity they pof- 
 fefs with each other becomes lefs than that they 
 have for oxygen, and at which oxygenation 
 muft neceffarily take place if oxygen be prefent. 
 
 We can readily conceive that the degree of 
 heat at which this phenomenon begins muft be 
 different in different bodies. Hence, on pur- 
 pofe to oxygenate mod bodies, efpecially the 
 greater part of the fimple fubftances, it is only 
 neceffary to expofe them to the influence of the 
 air of the atmcfphere in a convenient degree of 
 temperature. With refpeCt to lead, mercury, 
 and tin, this needs be but little higher than the 
 medium temperature of the earth ; but it re- 
 quires a more confiderable degree of heat to 
 oxygenate iron, copper, &c. by the dry way, or 
 when this operation is not affifted by moifture. 
 Sometimes oxygenation takes place with great 
 rapidity, and is accompanied by great fenfible 
 heat, light, and flame ; fuch is the combuftion 
 of phofphorus in atmofpheric air, and of iron 
 in oxygen gas. That of fulphur is lefs rapid ; 
 and the oxygenation of lead, tin, and moft of 
 the metals, takes place vaftly flower, and con- 
 fequently the difengagem'ent of caloric, and 
 more efpecially of light, is hardly fenfible. 
 
 Some 
 
OF CHEMISTRY. 187 
 
 Some fubftances have fo ftrong an affinity 
 with oxygen, and combine with it in fuch low 
 degrees of temperature, that we cannot procure 
 them in their unoxygenated ftate ; fuch is the 
 muriatic acid, which has not hitherto been de- 
 compofed by art, perhaps even not by nature, 
 and which confequently has only been found in 
 the ftate of acid. It is probable that many o- 
 ther fubftances of the mineral kingdom are ne- 
 ceflarily oxygenated in the common tempera- 
 ture of the atmofphere, and that being already 
 faturated with oxygen, prevents their farther ac- 
 tion upon that element. 
 
 There are other means of oxygenating fimple 
 fubftances befides expofure to air in a certain 
 degree of temperature, fuch as by placing them 
 in contact with metals combined with oxygen, 
 and which have little affinity with that element. 
 The red oxyd of mercury is one of the beft fub- 
 ftances for this purpofe, efpecially with bodies 
 which do not combine with that metal. In this 
 oxyd the oxygen is united with very little force 
 to the metal, and can be driven out by a degree 
 of heat only fufficient to make glafs red hot ; 
 wherefore fuch bodies as are capable of uniting 
 with oxygen are readily oxygenated, by means 
 of being mixed with red oxyd of mercury, and 
 moderately heated. The fame efteft may be, 
 to a certain degree, produced by means of the 
 black oxyd of manganefe, the red oxyd of lead, 
 
 the 
 
1 8 8 
 
 ELEMENTS 
 
 the oxyds of filver, and by mod of the metallic' 
 oxyds, if we only take care to choofe fuch as 
 have lefs affinity with oxygen than the bodies 
 they are meant to oxygenate. All the metallic 
 reductions and revivifications belong to this 
 clafs of operations, being nothing more than 
 oxygenations of charcoal, by means of the fe- 
 veral metallic oxyds. The charcoal combines 
 with the oxygen and with caloric, and efcapes 
 in form of carbonic acid gas, while the metal 
 remains pure and revivified, or deprived of the 
 oxygen which before combined with it in the 
 form of oxyd. 
 
 All combuftible fubftances may likewife be 
 oxygenated by means of mixing them with ni- 
 trat of potaffi or of foda, or with oxygenated 
 muriat of pot-afh, and fubjeCting the mixture to 
 a certain degree of heat ; the oxygen, in this 
 cafe, quits the nitrat or the muriat, and com- 
 bines with the combuftible body. This fpecies 
 of oxygenation requires to be performed with 
 extreme caution, and only with very fmall quan- 
 tities ; becaufe, as the oxygen enters into the 
 compofition of nitrats, and more efpecially of 
 oxygenated muriats, combined with almoft as 
 much caloric as is neceffary for converting it 
 into oxygen gas, this immenfe quantity of calo- 
 ric becomes fuddenly free the inflant of the 
 combination of the oxygen with the combuftible 
 
 body. 
 
OF CHEMISTRY. 189 
 
 body, and produces fuch violent explofions as 
 are perfe&ly irrefiftible. 
 
 By the humid way we can oxygenate mod 
 combuftible bodies, and convert mod of the 
 oxyds of the three kingdoms of nature into 
 acids. For this purpofe we chiefly employ the 
 nitric acid, which has a very flight hold of oxy- 
 gen, and quits it readily to a great number of 
 bodies by the afiiftance of a gentle heat. The 
 oxygenated muriatic acid may be ufed for feve- 
 ral operations of this kind, but not in them all. 
 
 I give the name of binary to the combina- 
 tions of oxygen with the Ample fubftances, be- 
 caufe in thefe only two elements are combined. 
 When three fubftances are united in one com- 
 bination I call it ternary , and quaternary when 
 the combination confifts of four fubftances 
 united. 
 
 Tajslx 
 
190 
 
 ELEMENTS 
 
 Table of the 
 
 combinations of Oxygen with the com* 
 pound radicals . 
 
 Names of the radi- Names of the refulting acids • 
 
 cals. New nomenclature . Old nomenclature . 
 
 «dic° a r UrlatiC } Nitro ™riatic acid Ac > ua re S !a ' 
 
 # 
 
 Tartaric 
 
 Malic 
 
 Citric 
 
 Pyro*lignous 
 
 Pyro- mucous 
 
 Pyro-tartarous 
 
 Oxalic 
 
 Acetic 
 
 Succinic 
 
 Benzoic 
 
 Camphoric 
 
 Gallic 
 
 * * 
 
 Tartarous acid 
 Malic acid 
 Citric acid 
 
 Pyro-lignous acid 
 
 Pyro-mucous acid 
 Pyro-tartarous acid 
 Oxalic acid 
 
 Acetous acid 
 
 Acetic acid 
 Succinic acid 
 Benzotic acid 
 Camphoric acid 
 
 Gallic acid 
 
 Unknown till lately. 
 Ditto. 
 
 Acid of lemons. 
 
 ‘ Empyreumatic acid of 
 wood. 
 
 Empyr. acid of fugar. 
 Empyr. acid of tartar. 
 Acid ef forel. 
 'Vinegar, or acid of 
 _ vinegar. 
 
 Radical vinegar. 
 Volatile fait of amber. 
 Flowers of benzoin. 
 Unknown till lately. 
 The aftringent princi- 
 pie of vegetables. 
 
 Laftic 
 
 Sacchola&ic 
 
 Formic 
 
 Bombic 
 
 Sebacic 
 
 Lithjc 
 
 Pruffic 
 
 Laflic acid 
 Saccholaflic acid 
 Formic acid 
 Bombic acid 
 Sebacic acid 
 Lithic acid 
 
 Pruffic acid 
 
 Acid of four whey. 
 Unknown till lately. 
 Acid of ants. 
 Unknown till lately. 
 Ditto. 
 
 Urinary calculus. 
 Colouring matter of 
 Pruffian blue. 
 
 Sect. 
 
 * Thefe radicals by a firft degree of oxygenation form vege- 
 table oxyds, as fugar, ftarch, mucus, &c. — A. 
 
 ** Thefe radicals by a firft degree of oxygenation form the 
 animal oxyds, as lymph, red part of the blood, animal fecre- 
 tions, & c^—A. 
 
OF CHEMISTRY. 
 
 1 9 * 
 
 Sect. V . — Obfervations upon the Combinations of 
 Oxygen with the Compound Radicals. 
 
 I publifhed a new theory of the nature and 
 formation of acids in the Memoirs of the Aca- 
 demy for 1776, p. 671. and 1778, p. 535. in 
 which I concluded, that the number of acids 
 rnuit be greatly larger than was till then fup- 
 pofed. Since that time, a new field of inquiry 
 » has been opened to chemifts ; and, inftead of 
 . five or fix acids which were then known, near 
 thirty new acids have been difcovered, by wdiich 
 means the number of known neutral falts have 
 been increafed in the fame proportion. The 
 nature of the acidifiable bafes, or radicals of the 
 acids, and the degrees of oxygenation they are 
 fufceptibie of, ftill remain to be inquired into. 
 I have already ihown, that almolt all the oxy- 
 dable and acidifiable radicals from the mineral 
 kingdom are fimpie, and that, on the contrary, 
 there hardly exifts any radical in the vegetable, 
 and more efpecially in the animal kingdom, but 
 is compofed of at leaft two fubftances, hydro- 
 gen and charcoal, and that azote and phofpho* 
 rus are frequently united to thefe, by which we 
 have compound radicals of two, three, and four 
 bafes or fimpie elements united. 
 
 From 
 
X9* ELEMENTS 
 
 From thefe obfervations, it appears that 
 vegetable and animal oxyds and acids may dif- 
 fer from each other in three feveral ways : ift, 
 According to the number of fimple acidifiable 
 elements of which their radicals are compofed : 
 sdly, According to the proportions in which 
 thefe are combined together : And, 3dly, Ac- 
 cording to their different degrees of oxygena- 
 tion : Which circumftances are more than fuf- 
 ficient to explain the great variety which nature 
 produces in thefe lubftances. It is not at all 
 furprifing, after this, that moft of the vegetable 
 acids are convertible into each other, nothing 
 more being requifite than to change the pro- 
 portions of the hydrogen and charcoal in their 
 compaction, and to oxygenate them in a great- 
 er or leffer degree. This has been done by Mr 
 Crell in fome very ingenious experiments, which 
 have been verified and extended by Mr Haffen- 
 fratz. From thefe it appears, that charcoal and 
 hydrogen, by a firfl oxygenation, produce tar- 
 tarous acid, oxalic acid by a fecond degree, and 
 acetous or acetic acid by a third, or higher oxy- 
 genation ; only, that charcoal feems to exift in 
 a rather fmaller proportion in the acetous and 
 acetic acids. The citric and malic acids differ 
 little from the preceding acids. 
 
 Ought we then to conclude that the oils are 
 the radicals of the vegetable and animal acids ? 
 I have already expreffed my doubts upon this 
 
 fubjeft : 
 
OF CHEMISTRY. 193 
 
 fubjed: ift, Although the oils appear to be 
 formed of nothing but hydrogen and charcoal, 
 we do not know if thefe are in the precife pro- 
 portion neceflary for conftituting the radicals of 
 the acids t 2dly, Since oxygen enters into the 
 compofition of thefe acids equally with hydro- 
 gen and charcoal, there is no more reafon for 
 fuppofing them to be compofed of oil rather 
 than of water or of carbonic acid. It is true 
 that they contain the materials neceflary for all 
 thefe combinations, but then thefe do not take 
 place in the common temperature of the atmoi- 
 phere ; all the three elements remain combined 
 in a ftate of equilibrium, which is readily de- 
 ftroyed by a temperature only a little above that 
 of boiling water *. 
 
 B b Table 
 
 * See Part I, Chap. XII. upon this fubje£t,~A^ 
 
194 
 
 ELEMENTS 
 
 Table of the Binary Combinations of Azote with the 
 Simple Subfiances . 
 
 Simple Refults of the Combinations . 
 
 Subfiancei. New Nomenclature . Old Nomenclature . 
 
 Caloric 
 
 Hydrogen 
 
 Oxygen 
 
 Charcoal , 
 
 Phofphorus. 
 
 Sulphur 
 
 Compound 
 
 radicals 
 
 Azotic gas 
 
 Ammoniac 
 Nitrous oxyd 
 Nitrous acid 
 Nitric acid 
 
 Oxygenated nitric acid 
 
 C Phlogifticated air, or 
 \ Mephitis. 
 
 Volatile alkali. 
 
 Bafe of Nitrous gas. 
 Smoaking nitrous acid. 
 Pale nitrous acid. 
 Unknown. 
 
 Metallic fub- 
 (lances 
 
 Lime 
 Magnefia 
 Barytes 
 Argill 
 Potafn 
 Soda 
 
 fThis combination is hitheito unknown; fhould it 
 j ever be difcovered, it will be called, according to 
 \ the principles of our nomenclature, Azuret of 
 | Charcoal. Charcoal dilfolves in azotic gas, and 
 forms carbonated azotic gas. 
 
 Azuret of phofphorus. Still unknown. 
 
 r Azuret of fulphur. Still unknown. We know 
 i that fulphur dilfolves in azotic gas, forming ful- 
 £ phurated azotic gas. 
 
 Azote combines with charcoal and hydrogen, and 
 fometimes with phofphorus, in the compound 
 cxydable and acidifiable bafes, and is generally 
 contained in the radicals of the animal acids. 
 
 Such combinations are hitherto unknown; if ever 
 difcovered, they will form metallic azurets, as 
 azuret of gold, of liiver, &c. 
 
 r 
 
 ! Entirely unknown. If ever difcovered, they will 
 1 form azuret of lime, azuret of magnefia, &c. 
 
 Sect. 
 
OF CHEMISTRY. 19J 
 
 Sect. VI . — Obfervations upon the Combinations of 
 
 Azote with the Simple Subjlances . 
 
 Azote is one of the moft abundant elements; 
 combined with caloric it forms azotic gas, or 
 mephitis, which compofes nearly two thirds of 
 the atmofphere. This element is always in the 
 ftate of gas in the ordinary preffure and tempe- 
 rature, and no degree of compreffion or of cold 
 has been hitherto capable of reducing it either 
 to a folid or liquid form. This is likewife one 
 of the effential conftituent elements of animal 
 bodies, in which it is combined with charcoal 
 and hydrogen, and fometimes with phofphorus ; 
 thefe are united together by a certain portion of 
 oxygen, by which they are formed into oxyds 
 or acids according to the degree of oxygena- 
 tion. Hence the animal fubftances may be va- 
 ried, in the fame way with vegetables, in three 
 different manners : iff, According to the num- 
 ber of elements which enter into the compofi- 
 tion of the bafe or radical : 2 dly, According to 
 the proportions of thefe elements: 3dly, Ac- 
 cording to the degree of oxygenation. 
 
 When combined with oxygen, azote forms 
 the nitrous and nitric oxyds and acids ; when 
 with hydrogen, ammoniac is produced. Its 
 combinations with the other fnnple elements 
 
 are 
 
> $6 ELEMENTS 
 
 are very little known ; to thefe we give the 
 name of Azurets, preferving the termination in 
 uret for all nonoxygenated compounds. It is 
 extremely probable that all the alkaline fubftan- 
 ces may hereafter be found to belong to this 
 genus of azurets. 
 
 The azotic gas may be procured from atxnof- 
 pheric air, by abforbing the oxygen gas which 
 is mixed with it by means of a folution of ful- 
 phuret of potafh, or fulphuret of lime. It re- 
 quires twelve or fifteen days to complete this 
 procefs, during which time the furface in con- 
 tad muft be frequency renewed by agitation, 
 and by breaking the pellicle which forms on the 
 top of the foiution. It may likewife be procu- 
 red by diffolving animal fubftances in dilute ni- 
 tric acid very little heated. In this operation 
 the azote is difengaged in form of gas, which 
 we receive under bell glafies filled with water 
 in the pneumato-chemical apparatus. We may 
 procure this gas by deflagrating nitre with char- 
 coal, or any other combuftible fubflance; when 
 with charcoal, the azotic gas is mixed with car- 
 bonic acid gas, which may be abforbed by a fo- 
 lution of cauflic alkali, or by lime water, after 
 which the azotic gas remains pure. We can 
 procure it in a fourth manner from combina- 
 tions of ammoniac with metallic oxyds, as point- 
 ed out by Mr de Fourcroy: The hydrogen of the 
 ammoniac combines with the oxygen of the 
 
OF CHEMISTRY. 197 
 
 oxyd, and forms water, whilft the azote being 
 left free efcapes in form of gas. 
 
 The combinations of azote were but lately 
 difcovered : Mr Cavendilh firft obferved it in 
 nitrous gas and acid, and Mr Berthollet in am- 
 moniac and the pruffic acid. As no evidence 
 of its decompofition has hitherto appeared, we 
 are fully entitled to confider azote as a limple 
 elementary fubftance. 
 
 Tab ls 
 
r *9& ELEMENTS 
 
 Table of the Binary Combinations of Hydrogen with 
 Simple Subjiances . 
 
 Simple Refulting Compounds . 
 
 Subjiances . 
 
 New Nomenclature . 
 
 Old Nafties. 
 
 Caloric 
 
 Azote 
 
 Oxygen 
 
 Hydrogen gas 
 
 Ammoniac 
 
 Water 
 
 Inflammable air. 
 Volatile Alkali. 
 Water. 
 
 Sulphur -j 
 
 Phofphorus * 
 
 r Hydruret of fulphur, or" 
 f fulphuret of hydrogen ( 
 Hydruret of phofphorus, or( 
 phofphuret of hydrogen 
 
 > Hitherto unknown ** 
 
 Charcoal 
 
 C Hydro-carbonous, or car* ] 
 £ bono-hydrous radicals f J 
 
 ^ Not known till lately. 
 
 Metallic fub' < 
 fiances, as 
 iron, &c. i 
 
 \ Metallic hydrurets J, as / 
 ; hydruret of iron, &c. < 
 
 r Hitherto unknown. 
 
 * Thefe combinations take place in the flate of gas, and 
 form, refpectively, fulphurated and phofphorated oxygen gas.— 
 
 A. 
 
 f This combination of hydrogen with charcoal includes the 
 fixed and volatile oils, and forms the radicals of a confiderable 
 part of the vegetable and animal oxyds and acids. When it 
 takes place in the ftate of gas it forms carbonated hydrogen 
 
 gas.— A. 
 
 J None of thefe combinations are known, and it is probable 
 that they cannot exift, at lead in the ufual temperature of the 
 atmofphere, owing to the great affinity of hydrogen for calo- 
 ric. — A. 
 
 Sect. 
 
Sect. VII . — Obfervations upon Hydrogen , 
 Combinations with Simple Subjlances . 
 
 and its 
 
 Hydrogen, as its name exprefTes, is one of the 
 conftituent elements of water, of which it forms 
 fifteen hundredth parts by weight, combined with 
 eighty-five hundredth parts of oxygen. This 
 fubftance, the properties and even exiftence of 
 which was unknown till lately, is very plentiful- 
 ly diftributed in nature, and ads a very confi- 
 derable part in the proceffes of the animal and 
 vegetable kingdoms. As it pofTeffes fo great 
 affinity with caloric as only to exift in the ftate 
 of gas, it is confequently impoffible to procure 
 it in the concrete or liquid ftate, independent 
 of combination. 
 
 To procure hydrogen, or rather hydrogen 
 gas, we have only to fubjed water to the adion 
 of a fubftance with which oxygen has greater 
 affinity than it has to hydrogen ; by this means 
 the hydrogen is fet free, and, by uniting with 
 caloric, aflumes the form of hydrogen gas. Red 
 hot iron is ufually employed for this purpofe : 
 The iron, during the procefs, becomes oxy- 
 dated, and is changed into a fubftance refem- 
 bling the iron ore from the ifland of Elba. In 
 this ftate of oxyd it is much lefs attradible by 
 
 the 
 
aoo ELEMENTS 
 
 the magnet, and diffolves in acids without effer- 
 vefcence. 
 
 Charcoal, in a red heat, has the fame power 
 of decompofing water, by attra&ing the oxygen 
 from its combination with hydrogen. In this 
 procefs carbonic acid gas is formed, and mixes 
 with the hydrogen gas, but is eafily feparated 
 by means of water or alkalies, which abforb the 
 carbonic acid, and leave the hydrogen gas pure* 
 We may likewife obtain hydrogen gas by dif- 
 folving iron or zinc in dilute fulphuric acid* 
 Thefe two metals decompofe water very flowly, 
 and with great difficulty, when alone, but do it 
 with great eafe and rapidity when aflifted by ful- 
 phuric acid ; the hydrogen unites with caloric 
 during the procefs, and is difengaged in form 
 of hydrogen gas, while the oxygen of the water 
 unites with the metal in the form of oxyd, which 
 is immediately diffoived in the acid, forming a 
 fulphat of iron or of zinc. 
 
 Some very diftinguifhed chemifts confider hy- 
 drogen as the phlogijlon of Stahl ; and as that 
 celebrated chemift admitted the exiftence of 
 phlogiflon in fulphur, charcoal, metals, &c. they 
 are of courfe obliged to fuppofe that hydrogen 
 exifls in all thefe fubflances, though they can- 
 not prove their fuppofition ; even if they could, 
 it would not avail much, fince this difengage- 
 ment of hydrogen is quite infufficient to explain 
 the phenomena of calcination and combuftion. 
 
 We 
 
OF CHEMISTRY, 
 
 201 
 
 We muft always recur to the examination of this 
 queftion, “ Are the heat and light, which are 
 difengaged during the different fpecies of com- 
 bullion, furniflied by the burning body, or by 
 the oxygen which combines in all thefe opera- 
 tions J” And certainly the fuppofition of hydro- 
 gen being difengaged throws no light whatever 
 upon this queftion. Befides, it belongs to thofe 
 who make fuppofitions to prove them ; and, 
 doubtlefs, a do&rine which without any fuppo- 
 fition explains the phenomena as well, and as 
 naturally, as theirs does by fuppofition, has a? 
 lead the advantage of greater fimplicity *. 
 
 Cc 
 
 Table 
 
 * Thofe who wifn to fee what has been faid upon 
 this great chemical queftion by Meffrs de Morveau, 
 Berthollet, De Fourcroy, and myfelf, may confult our 
 tranflation of Mr Kirwan’s Effay upon Phlogifton. — A. 
 
 
202 
 
 ELEMENTS 
 
 Table of the Binary Combinations of Sulphur wt& 
 Simple Subfiances. 
 
 Shnple Refulting Compounds . 
 
 Sub/Ian ccs. 
 
 Nemo Nomenclature . 
 
 Old Nomenclature . 
 
 Caloric 
 
 Sulphuric gas 
 r Oxyd of fulphur 
 
 Soft fulphur. 
 
 Oxygerf 
 
 < Sulphurous acid 
 
 Sulphureous acid. 
 
 
 £ Sulphuric acid 
 
 Vitriolic acid. 
 
 Hydrogen 
 
 Sulphuret of hydrogen 
 
 
 Azote 
 
 azote 
 
 £ Unknown Combina- 
 
 Phofphorus 
 
 phofphorus 
 
 £ tions. 
 
 Charcoal 
 
 charcoal 
 
 j 
 
 Antimony 
 
 antimony 
 
 Crude antimony. 
 
 Silver 
 
 filver 
 
 
 Arfeniq 
 
 arfenic 
 
 Orpiment, realgar. 
 
 Bifmuth 
 
 bifmuth 
 
 Cobalt 
 
 cobalt 
 
 
 Copper 
 
 copper 
 
 Copper pyrites. 
 
 Tin 
 
 tin 
 
 
 Iron 
 
 iron 
 
 Iron pyrites. 
 
 Manganefe 
 
 manganefe 
 
 
 Mercury 
 
 mercury 
 
 C Ethiops mineral, 
 £ cinnabar. 
 
 Molybdena 
 
 molybdena! 
 
 
 Nickel 
 
 nickel 
 
 
 Gold 
 
 gold 
 
 
 Platina 
 
 platina 
 
 
 Lead 
 
 lead 
 
 Galena. 
 
 Tungftein 
 
 tungftein 
 
 Blende. 
 
 Zinc 
 
 zinc 
 
 r Alkaline liver of fill 
 
 Potafh 
 
 potafh 
 
 < phur with fixed ve* 
 (_ getable alkali. 
 
 
 
 C Alkaline liver of ful< 
 
 Soda 
 
 foda 
 
 < phur with fixed mi- 
 
 Ammoniac 
 
 Lime 
 
 Magnefia 
 
 Barytes 
 
 Argiil 
 
 ammoniac 
 
 lime 
 
 magnefia 
 
 barytes 
 
 argiil 
 
 C neral alkali. 
 ("Volatile liver of fill* 
 < phur, fmoaking li* 
 C quor of Boyle. 
 
 C Calcareous liver of ful- 
 (_ phur. 
 
 ( Magnefian liver of fub 
 £ phur. 
 
 C Barytic liver of ful< 
 £ phur. 
 
 Yet unknown. 
 
 Sect, 
 
OF CHEMISTRY. 
 
 203 
 
 Sect. VIIL — Obfervations on Sulphur , and its 
 Combinations . 
 
 Sulphur is a combuHible fubHance, having a 
 very great tendency to combination ; it is na- 
 turally in a folid Hate in the ordinary tempera- 
 ture, and requires a heat fomewhat higher than 
 boiling water to make it liquify. Sulphur is 
 formed by nature in a confiderable degree of 
 purity in the neighbourhood of volcanos ; we 
 find it likewife, chiefly in the Hate of fulphuric 
 acid, combined with argill in aluminous fchif- 
 tus, with lime in gypfum, &c. From thefe com- 
 binations it may be procured in the Hate of ful- 
 phur, by carrying off its oxygen by means of 
 charcoal in a red heat ; carbonic acid is form- 
 ed, and efcapes in the Hate of gas ; the fulphur 
 remains combined with the clay, lime, &c. in 
 the Hate of fulphuret, which is decompofed by 
 acids ; the acid unites with the earth into a neu- 
 tral fait, and the fulphur is precipitated. 
 
 Table 
 
✓ 
 
 204 ELEMENTS 
 
 Table of the Binary Combinations of Phofphorus 
 with the Simple Subfiances. 
 
 Simple Subflanees . 
 
 Caloric 
 
 Oxygen. 
 
 Hydrogen 
 
 Azote 
 
 Sulphur 
 
 Charcoal 
 
 Metallic fubftances 
 
 Fotafh 
 
 Soda 
 
 Ammoniac - 
 Lime 
 Barytes 
 Magnefi a 
 Argil! 
 
 Refulting Compounds. 
 
 Phofphoric gas. 
 
 Oxyd of phofphorus. 
 Phofphorous acid. 
 Phofphoric acid. 
 Phofphuret of hydrogen. 
 Phofphuret of azote. 
 Phofphuret of Sulphur. 
 Phofphuret of charcoal. 
 Phofphuret of metals *<> 
 
 Phofphuret of Potafh, 
 Soda, &c. •(• 
 
 Sect, 
 
 * Of all theie combinations of phofphorus with 
 metals, that with iron only is hitherto known, forming 
 the fubftance formerly called Siderite ; neither is it yet 
 afcertalned whether, in this combination, the phofpho- 
 rus be oxygenated or not. — A. 
 
 f Thefe combinations of phofphorus with the alka- 
 lies and earths are not yet known ; and, from the ex- 
 periments of Mr Gengembre, they appear to be im- 
 poflible. — A. 
 
Sect. I X.—Ob/ervations upon Phofphorus , and 
 its Combinations . 
 
 Phofphorus is a fimple combuftible fubftance, 
 which was unknown to chemifts till 1667, when 
 it was difcovered by Brandt, who kept the pro- 
 cefs fecret; foon after Kunkel found out Brandt’s 
 method of preparation, and made it public. It 
 has been ever fince known by the name of Kun- 
 kei’s phofphorus. It was for a long time pro. 
 cured only from urine ; and, though Homberg 
 gave an account of the procefs in the Memoirs 
 of the Academy for 1692, ail the philofophers 
 of Europe were fupplied with it from England. 
 It was firft made in France in 1737, before a 
 committee of the Academy at the Royal Garden. 
 At prefent it is procured in a more commodious 
 and more oeconomical manner from animal 
 bones, which are real calcareous phofphats, ac- 
 cording to the procefs of Meflrs Gahn, Scheele, 
 Rouelle, &c. The bones of adult animals be- 
 ing calcined to whitenefs, are pounded, and paf- 
 fed through a fine filk fieve ; pour upon the fine 
 powder a quantity of dilute fulphuric acid, lefs 
 than is fufficient for diffolving the whole. This 
 acid unites with the calcareous earth of the 
 bones into a fulphat of lime, and the phofpho- 
 ric acid remains free in the liquor. The liquid 
 
ELEMENTS 
 
 is decanted off, and the refiduum walked with 
 boiling water ; this water which has been ufed 
 to walh out the adhering acid is joined with 
 what was before decanted off, and the whole is 
 gradually evaporated ; the diffolved fulphat of 
 lime criftallizes in form of filky threads, which 
 are removed, and by continuing the evaporation 
 we procure the phofphoric acid under the ap- 
 pearance of a white pellucid glafs. When this 
 is powdered, and mixed with one third its weight 
 of charcoal, we procure very pure phofphorus 
 by fublimation. The phofphoric acid, as pro- 
 cured by the above procefs, is never fo pure as 
 that obtained by oxygenating pure phofphorus 
 either by combuftion or by means of nitric acid; 
 wherefore this latter fhould always be employed 
 in experiments of refearch. 
 
 Phofphorus is found in almoft all animal fub- 
 flances, and in fome plants which give a kind 
 of animal analyfis. In all thefe it is ufually 
 combined with charcoal, hydrogen, and azote, 
 forming very compound radicals, which are, for 
 the moft patt, in the Hate of oxyds by a firft 
 degree of union with oxygen. The difcovery 
 of Mr Haffenfratz, of phofphorus being contain- 
 ed in charcoal, gives reafon to fufpect that it is 
 more common in the vegetable kingdom than 
 has generally been fuppofed: It is certain, that, 
 by proper proceffes, it may be procured from 
 every individual of fome of the families of plants. 
 
! OF CHEMISTRY. s CLoy 
 
 As no experiment has hitherto given reafon to 
 fufpect that phofphorus is a compound body, I 
 have arranged it with the fimple or elementary 
 fubftancesi It takes fire at the temperature of 
 3 2° (104°) of the thermometer. 
 
 Table of the Binary Combinations of Charcoal* 
 
 Simple 
 Subjiances • 
 
 Oxygen 
 
 Sulphur 
 
 Phofphorus 
 
 Azote 
 
 Hydrogen 
 
 Refulttng Compounds. 
 
 C Oxyd of charcoal 
 £ Carbonic acid 
 Carburet of fulphur 
 Carburet of phofphorus 
 Carburet of azote 
 C Carbono-hydrous radical 
 l Fixed and volatile oils 
 
 Metallic fub- ) Carburets ofme tals 
 fiances 3 
 
 Unknown. 
 
 Fixed air, chalky acid* 
 ^ Unknown. 
 
 f Of thefe only the car- 
 | burets of iron and 
 <{ zinc are known, and 
 
 | were formerly called 
 
 ^ Plumbago. 
 
 Unknown. 
 
 Sect, 
 
*>8 ELEMENTS 
 
 Sect. X . — Obfervations upon Charcoal. } and its 
 Combinations with Simple Sub/lances* 
 
 As charcoal has not been hitherto decompo- 
 fed, it muft, in the prefent ftate of our know- 
 ledge, be confidered as a fimple fubftance. By 
 modern experiments it appears to exift ready 
 formed in vegetables j and I have already re- 
 marked, that, in thefe, it is combined with hy- 
 drogen, fometimes with azote and phofphorus, 
 forming compound radicals, which may be 
 changed into oxyds or acids according to their 
 degree of oxygenation. 
 
 To obtain the charcoal contained in vegetable 
 or animal fubftances, we fubjedt them to the 
 a&ion of fire, at firft moderate, and afterwards 
 very ftrong, on purpofe to drive off the lad por- 
 tions of water, which adhere very obftinately to 
 the charcoal. For chemical purpofes, this is 
 ufually done in retorts of done-ware or porcel- 
 lain, into which the wood, or other matter, is 
 introduced, and then placed in a reverberatory 
 furnace, railed gradually to its greatefl hdat : 
 The heat volatilizes, or changes into gas, all the 
 parts of the body fufceptible of combining with 
 caloric into that form, and the charcoal, being 
 more fixed in its nature, remains in the retort 
 
 combined 
 
OF CHEMISTRY. 209 
 
 combined with a little earth and fome fixed 
 falts. 
 
 In the bufinefs of charring wood, this is done 
 by a lefs expenfive procefs. The wood is dif- 
 pofed in heaps, and covered with earth, fo as to 
 prevent the accefs of any more air than is ab- 
 solutely neceffary for Supporting the fire, which 
 is kept up till all the water and oil is driven off, 
 after which the fire is extinguifhed by fhutting 
 up all the air-holes. 
 
 We may analyfe charcoal either by combuf- 
 tion in air, or rather in oxygen gas, or by 
 means of nitric acid. In either cafe we convert 
 it into carbonic acid, and Sometimes a little pot- 
 aih and fome neutral falts remain. This analy- 
 sis has hitherto been but little attended to by 
 chemifts ; and we are not even certain if pot- 
 afh exifts in charcoal before combuftion, or 
 whether it be formed by means of fome un- 
 jknown combination during that procefs. 
 
 Sect. XI. — Obfervations upon the Muriatic , Flu- 
 oric ^ and Boracic Radicals , and their Combina- 
 tions. 
 
 As the combinations of thefe fubflances, either 
 with each other, or with the other combufiible 
 bodies, are hitherto entirely unknown, we have 
 D d not 
 
210 
 
 ELEMENTS 
 
 not attempted to form any table for their no- 
 meiici .ture. We only know that thefe radicals; 
 are fukeptible of oxygenation, and of forming 
 the muriatic ; fluoric, and boracic acids, and 
 tha. in th acid ftate they enter into a number 
 of c~ omations, to be afterwards detailed. 
 Cheiniftry has hitherto been unable to difoxy- 
 genate any of them, fo as to produce them in a 
 fimple ftate. For this purpofe, fome fubftance 
 muft be employed to which oxygen has a 
 ftronger affinity than to their radicals, either by 
 means of Angle affinity, or by double ele&ive 
 attra&ion. All that is known relative to the 
 origin of the radicals of thefe acids will be men- 
 tioned in the fe£Hons fet apart for confidering 
 their combinations with the falifiable bafes. 
 
 Sect. XII .—Obfervations upon the Combinations 
 of Metals with each other . 
 
 Before clofmg our account of the fimple or 
 elementary fubftances, it might be fuppofed ne- 
 ceflary to give a table of alloys or combinations 
 of metals with each other ; but, as fuch a table 
 would be both exceedingly voluminous and 
 very unfatisfactory, without going into a feries 
 of experiments not yet attempted, I have 
 thougnt it aavifeable to omit it altogether. All 
 
 that 
 
OF CHEMISTRY. 
 
 21 1 
 
 that is neceffary to be mentioned is, that thefe 
 alloys fhould be named according to the metal 
 in largeft proportion in the mixture or combi- 
 bination ; thus the term alloy of gold and fiber, 
 or gold alloyed with filver, indicates that gold 
 is the predominating metal. 
 
 Metallic alloys, like all other combinations, 
 have a point of faturation. It would even ap- 
 pear, from the experiments of Mr de la Briche, 
 that they have two perfectly diftinft degrees of 
 faturation. 
 
 
 Table 
 
212 
 
 ELEMENTS 
 
 Table of the Combinations of Azote in the flate of Ni- 
 trous Acid with the Salifiable Bafes , arranged accor- 
 ding to the affinities of thefe Bafes with the Acid • 
 
 Haines of the hafes . 
 
 Barytes 
 
 Potafh 
 
 Soda 
 
 Lime 
 
 Magnefia 
 
 Ammoniac 
 
 Argill 
 
 Oxyd of zinc 
 iron 
 
 manganefe 
 
 cobalt 
 
 nickel 
 
 lead 
 
 tin 
 
 copper 
 
 bifmuth 
 
 antimony 
 
 arfenic 
 
 mercury 
 
 Names of the neutral fait 
 New nomenclature . 
 
 Nitrite of barytes, 
 potafh. 
 foda. 
 lime, 
 magnefia. 
 ammoniac, 
 argill. 
 
 zinc. 
 
 iron. 
 
 manganefe. 
 
 cobalt. 
 
 nickel. 
 
 lead. 
 
 tin. 
 
 copper. 
 
 bifmuth. 
 
 antimony. 
 
 arfenic. 
 
 mercury. 
 
 Notes . 
 
 Thefe falts are only 
 known of late, and 
 have received no par- 
 ticular name in the old 
 nomenclature. 
 
 As metals difiblve 
 both in nitrous and 
 nitric acids, metallic 
 falts mult of confe- 
 quence be formed ha- 
 ving different degrees 
 of oxygenation. Thofe 
 wherein the metal is 
 leaft oxygenated muff 
 be calledNitrites,when 
 more fo, Nitrats ; but 
 the limits of this di- 
 ftin&ion are difficultly 
 afcertainable. The old- 
 der chemifts were not 
 acquainted with any of 
 thefe falts. 
 
 filver r It is extremely probable that gold, filver 9 
 gold \ and platina only form nitrats, and cannot fub- 
 platina £fifl in the (late of nitrites. 
 
 Tabls 
 
OF CHEMISTRY. 
 
 3x5 
 
 Table of the Combinations of Azote , completely fatura- 
 ud with Oxygen , in the Jlate of Nitric Acid, with 
 the Salifiable Safes, in the order of the affinity with 
 the Acid. 
 
 Safes . 
 
 Names of the refulting neutral falts • 
 New nomenclature . Old nomenclature. 
 
 Barytes 
 
 Potalh 
 
 Soda 
 
 • 
 
 Lime 
 
 Magnefia 
 
 Ammoniac 
 
 Argill 
 
 Oxyd of zinc 
 iron 
 
 manganefe 
 
 cobalt 
 
 nickel 
 
 lead 
 
 tin 
 
 copper 
 
 bifmuth 
 
 antimony 
 
 arfenic 
 
 mercury 
 
 filler 
 
 gold 
 
 platina 
 
 Nitrat of barytes 
 
 potalh 
 
 foda 
 
 lime 
 
 magnefia 
 
 ammoniac 
 
 argil! 
 
 zinc 
 
 iron 
 
 manganefe 
 
 cobalt 
 
 nickel 
 
 lead 
 
 tin 
 
 copper 
 
 bifmuth 
 
 antimony 
 
 arfenic 
 
 mercury 
 
 filver 
 
 gold 
 
 platina 
 
 C Nitre, with a bafe of 
 £ heavy earth. 
 
 C Nitre, faltpetre. Nitre 
 £ with bafe of potalh. 
 ^Quadrangular nitre. 
 < Nitre with bafe of 
 C mineral alkali. 
 Calcareous nitre. Nitre 
 with calcareous bafe. 
 Mother water of ni- 
 tre, or faltpetre. 
 
 C Magnefian nitre. Nitre 
 £ with bafe of magnefia. 
 Ammoniacal nitre. 
 Nitrous alum. Argil- 
 laceous nitre. Nitre 
 with bafe of earth of 
 alum. 
 
 Nitre of zinc. 
 
 C Nitre of iron. Martial 
 £ nitre. Nitrated iron. 
 Nitre of manganefe. 
 Nitre of cobalt. 
 
 Nitre of nickel. 
 
 C Saturnine nitre. Nitre 
 £ of lead. 
 
 Nitre of tin. 
 
 C Nitre of copper or of 
 £ Venus. 
 
 Nitre of bifmuth. 
 
 Nitre of antimony. 
 Arfenical nitre. 
 Mercurial nitre. 
 
 C Nitre of filver or luna. 
 
 I 
 
 Lunar cauftic. 
 Nitre of gold. 
 Nitre of platina. 
 
 Sect. 
 
ELEMENTS 
 
 214 
 
 Sect. XIII . — Obfervations upon the Nitrous and 
 Nitric Acids , and their Combinations . 
 
 The nitrous and nitric acids are procured 
 from a neutral fait long known in the arts un- 
 der the name of faltpetre. This fait is extra&ed 
 by lixiviation from the rubbifh of old buildings, 
 from the earth of cellars, ftables, or barns, and 
 in general of all inhabited places. In thefe 
 earths the nitric acid is ufually combined with 
 lime and magnefia, fometimes with potafh, and 
 rarely with argill. As all thefe falts, excepting 
 the nitrat of potafh, attract the moifture of the 
 air, and confequently would be difficultly pre- 
 fer ved, advantage is taken, in the manufactures 
 of faltpetre and the royal refining- houfe, of the 
 greater affinity of the nitric acid to potafh than 
 thefe other bafes, by which means the lime, 
 magnefia, and argill, are precipitated, and all 
 thefe nitrats are reduced to the nitrat of potafh 
 or faltpetre *. 
 
 The nitric acid is procured from this fait by 
 diflillation, from three parts of pure faltpetre ! 
 decompofed by one part of concentrated ful- 
 
 phuric 
 
 * Saltpetre is likewife procured in large quantities 
 by lixiviating the natural foil in fome parts of Bengal, 
 and of the Ruffian Ukraia.— E. 
 

 OF CHEMISTRY. aij 
 
 I phuric acid, in a retort with Woulfe’s appara- 
 tus, (PI. IV. fig. i.) having its bottles half fill- 
 ed with water, and all its joints carefully luted, 
 i The nitrous acid paffes over in form of red va- 
 pours furcharged with nitrous gas, or, in other 
 words, not faturated with oxygen. Part of the 
 acid condenfes in the recipient in form of a 
 \ dark orange red liquid, while the reft combines 
 with the water in the bottles. During the dif- 
 tillation, a large quantity of oxygen gas efcapes, 
 owing to the greater affinity of oxygen to calo- 
 ric, in a high temperature, than to nitrous acid, 
 though in the ufual temperature of the atmo- 
 fphere this affinity is reverfed. It is from the 
 difengagement of oxygen that the nitric acid of 
 the neutral fait is in this operation converted 
 l into nitrous acid. It is brought back to the 
 > ftate of nitric acid by heating over a gentle fire, 
 which drives off the fuperabundant nitrous gas, 
 and leaves the nitric acid much diluted with, 
 water. 
 
 Nitric acid is procurable in a more concen- 
 trated ftate, and with much lefs lofs, by mixing 
 very dry clay with faltpetre. This mixture is 
 put into an earthern retort, and diftilled with a 
 ftrong fire. The clay combines with the pot- 
 affi, for which it has great affinity, and the ni- 
 tric acid paffes over, flightly impregnated with 
 nitrous gas. This is eafily difengaged by heat- 
 ing the acid gently in a retort, a final! quantity 
 
 of 
 
ELEMENTS 
 
 $16 
 
 of nitrous gas paffes over into the recipient, 
 and very pure concentrated nitric acid remains 
 in the retort. 
 
 We have already feen that azote is the nitric 
 radical. If to 20 ^ parts, by weight, of azote 
 43I- parts of oxygen be added, 64 parts of nitrous 
 gas are formed ; and, if to this we join 36 addi- 
 tional parts of oxygen, 100 parts of nitric acid 
 refult from the combination. Intermediate quan- 
 tities of oxygen between thefe two extremes of 
 oxygenation produce different fpecies of nitrous 
 acid, or, in other words, nitric acid lefs or 
 more impregnated with nitrous gas. I afcer- 
 tained the above proportions by means of de- 
 compofition ; and, though I cannot anfwer for 
 their abfolute accuracy, they cannot be far re- 
 moved from truth. Mr Cavendilh, who firft 
 Ihowed by fynthetic experiments that azote is 
 the bafe of nitric acid, gives the proportions of 
 azote a little larger than I have done ; but, as 
 it is not improbable that he produced the ni- 
 trous acid and not the nitric, that circumftance 
 explains in fome degree the difference in the 
 refults of our experiments. 
 
 As, in all experiments of a philofophical na- 
 ture, the utmoft poffible degree of accuracy is 
 required, we muff procure the nitric acid for 
 experimental purpofes, from nitre which has 
 been previoufly purified from all foreign matter. 
 If, after diflillation, any fulphuric add is fu- 
 
 fpefted 
 
OF CHEMISTRY, 217 
 
 fpe&ed in the nitric acid, it is eafily feparated 
 by dropping in a little nitrat of barytes, fo long 
 as any precipitation takes place ; the fulphuric 
 acid, from its greater affinity, attra&s the ba- 
 rytes, and forms with it an infoluble neutral 
 fait, which falls to the bottom. It may be puri- 
 fied in the fame manner from muriatic acid, by 
 dropping in a little nitrat of filver fo long as 
 any precipitation of muriat of filver is produced* 
 When thefe two precipitations are finished, dif- 
 till off about feven- eighths of the acid by a gen- 
 tle heat, and what comes over is in the mod 
 perfect degree of purity. 
 
 The nitric acid is one of the mod prone to 
 combination, and is at the fame time very eafily 
 decompofed. Almod all the fimple fubflances, 
 with the exception of gold, filver, and platina, 
 rob it lefs or more of its oxygen ; fome of them 
 even decompofe it altogether. It was very an- 
 ciently known, and its combinations have been 
 more dudied by chemifts than thofe of any 
 other acid. Thefe combinations were named 
 nitres by Mefirs Macquer and Beaume ; but we 
 have changed their names to nitrats and nitrites, 
 according as they are formed by nitric or by 
 nitrous acid, and have added the fpecific name 
 of each particular bafe, to didinguifn the feve- 
 ral combinations from each other. 
 
 E e 
 
 Table 
 
I 
 
 218 ELEMENTS 
 
 Table of the Combinations of Sulphuric Acid with the 
 Salifiable Bafes , in the order of affinity . 
 
 Names of the lafe 
 Barytes Sulphat of barytes 
 
 Refulting 
 
 New nomenclature. 
 
 Potafli 
 
 Soda 
 
 Lime 
 
 Magnefia 
 
 Ammoniac 
 
 Argill 
 
 Oxydof zinc 
 
 potafh 
 
 foda 
 
 lime 
 
 magnefia 
 
 ammoniac 
 
 argill 
 
 zinc 
 
 compounds . 
 
 Old nomenclature. 
 
 C Heavy fpar. Vitriol 
 \ of heavy earth. 
 f Vitriolated tartar. Sal 
 < de duobus. Arcanum 
 ( __ duplicatam. 
 
 Glauber’s fait. 
 
 C Selenite, gypfum, cal- 
 £ careous vitriol. 
 
 C Epfom falt,fedlitz fait, 
 £ magnefian vitriol. 
 
 C Glauber’s fecret fal 
 £ ammoniac. 
 
 Alum. 
 
 r White vitriol, goflar 
 -J vitriol, white coperas, 
 t vitriol of zinc. 
 "Green coperas, green 
 
 iron 
 
 iron -< 
 
 v* vitriol, martial vitri- 
 ol, vitriol of iron. 
 
 manganefe 
 
 manganefe 
 
 Vitriol of manganefe. 
 
 cobalt 
 
 cobalt 
 
 Vitriol of cobalt. 
 
 nickel 
 
 nickel 
 
 Vitriol of nickel. 
 
 lead 
 
 lead 
 
 Vitriol of lead. 
 
 tin 
 
 tin 
 
 Vitriol of tin. 
 
 'Blue coperas, blue vi- 
 
 copper 
 
 copper *< 
 
 l triol, Roman vitriol, 
 vitriol of copper. 
 
 bifmuth 
 
 bifmuth 
 
 Vitriol of bifmuth. 
 
 antimony 
 
 antimony 
 
 Vitriol of antimony. 
 
 arfenic 
 
 arfenic 
 
 Vitriol of arfenic. 
 
 mercury 
 
 mercury 
 
 Vitriol of mercury. 
 
 111 v er 
 
 fiver 
 
 Vitriol of filver. 
 
 gold 
 
 gold 
 
 Vitriol of gold. 
 
 platina 
 
 platina 
 
 Vitriol of platina. 
 
 Sect. 
 
OF CHEMISTRY. 
 
 219 
 
 Sect. XIV . — Obfervations upon Sulphuric Acid 
 and its Combinations. 
 
 For a long time this acid was procured by 
 diftillation from fulphat of iron, in which ful- 
 phuric acid and oxyd of iron are combined, 
 according to the procefs defcribed by Bafd Va- 
 lentine in the fifteenth century ; but, in modern 
 times, it is procured more ©economically by the 
 combuftion of fulphur in proper veflels. Both 
 to facilitate the combuftion, and to aflift the 
 oxygenation of the fulphur, a little powdered 
 faltpetre, nitrat of potafli, is mixed with it ; 
 the nitre is decompofed, and gives out its oxy- 
 gen to the fulphur, w 7 hich contributes to its 
 converfion into acid. Notwithftanding this ad- 
 dition, the fulphur will only continue to burn 
 in clofe veffels for a limited time ; the combi- 
 nation ceafes, becaufe the oxygen is exhaufted, 
 and the air of the veflels reduced almoft to pure 
 azotic gas, and becaufe the acid itfelf remains 
 long in the ftate of vapour, and hinders the 
 progrefs of combuftion. 
 
 In the manufactories for making fulphuric 
 acid in the large way, the mixture of nitre and 
 fulphur is burnt in large clofe built chambers 
 lined with lead, having a little water at the bot- 
 tom for facilitating the condenfation of the va- 
 pours. 
 
220 
 
 ELEMENTS 
 
 pours. Afterwards, by diftillation in large re- 
 torts with a gentle heat, the water paffes over, 
 flightly impregnated with acid, and the fulphuric 
 acid remains behind in a concentrated flate. It 
 is then pellucid, without any flavour, and near- 
 ly double the weight of an equal bulk of water. 
 This procefs would be greatly facilitated, and 
 the combuftion much prolonged, by introdu- 
 cing frelh air into the chambers, by means of 
 feveral pairs of bellows directed towards the 
 flame of the fulphur, and by allowing the ni- 
 trous gas to efcape through long ferpentine ca- 
 nals, in conta& with water, to abforb any ful- 
 phuric or fulphurous acid gas it might contain. 
 
 By one experiment, Mr Berthollet found that 
 6 9 parts of fulphur in combuftion, united with 
 31 parts of oxygen, to form 100 parts of ful- 
 phuric acid ; and, by another experiment, made 
 in a different manner, he calculates that 100 
 parts of fulphuric acid confifts of 72 parts ful- 
 phur, combined with 28 parts of oxygen, all 
 by weight. 
 
 This acid, in common with every other, can 
 only diffolve metals when they have been previ- 
 oufly oxydated ; but moft of the metals are ca- 
 pable of decompofing a part of the acid, fo as 
 to carry off a fufficient quantity of oxygen, to 
 render themfelves foluble in the part of the acid 
 which remains undecompofed. This happens 
 with filver, mercury, iron, and zinc, in boiling 
 
 concentrated 
 
OF CHEMISTRY. 
 
 221 
 
 concentrated fulphuric acid ; they become firft 
 oxydated by decompofing part of the acid, and 
 then diffolve in the other part ; but they do not 
 fufficiently difoxygenate the decompofed part of 
 the acid to reconvert it into fulphur ; it is only 
 reduced to the ftate of fulphurous acid, which, 
 being volatilifed by the heat, flies off in form of 
 fulphurous acid gas. 
 
 Silver, mercury, and all the other metals ex- 
 cept iron and zinc, are infoluble in diluted ful- 
 phuric acid, becaufe they have not fufficient af- 
 finity with oxygen to draw it off from its com- 
 bination either with the fulphur, the fulphurous 
 acid, or the hydrogen ; but iron and zinc, be- 
 ing aflifted by the adtion of the acid, decompofe 
 the water, and become oxydated at its expence, 
 without the help of heat. 
 
 Table 
 
ELEMENTS 
 
 222 
 
 Table of the Combinations of the Sulphurous Acid 
 with the Salifiable Bafes , in the order of affinity . 
 
 Names of the Bafes, 
 
 Names of the Neutral Salts, 
 
 Barytes 
 
 Sulphite of barytes. 
 
 Potafh 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Lime 
 
 lime. 
 
 Magnefia 
 
 inagnefia. 
 
 Ammoniac 
 
 ammoniac. 
 
 Argill 
 
 argill. 
 
 Oxyd of zinc 
 
 zinc. 
 
 iron 
 
 iron. 
 
 manganefe 
 
 manganefe. 
 
 cobalt 
 
 cobalt. 
 
 nickel 
 
 nickel. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 copper 
 
 copper. 
 
 bifmuth 
 
 bifmuth. 
 
 antimony 
 
 antimony. 
 
 arfenic 
 
 arfenic. 
 
 mercury 
 
 mercury. 
 
 filver 
 
 filver. 
 
 gold 
 
 gold. 
 
 platina 
 
 platina. 
 
 Sect*, 
 
 Note . — — The only one of thefe falts known to the 
 old chemifts was the fulphite of potafh, tinder the name 
 of Stahl’s fulphureous fait. So that, before our new no- 
 menclature, thefe compounds muft have been named 
 Stahl’s fulphureous falt> having bafe of fixed vegetable 
 aikali, and fo of the reft. 
 
 In this Table we have followed Bergman’s order of 
 affinity of the fulphuric acid, which is the fame in re- 
 gard to the earths and alkalies, but it is not certain if 
 the order be the fame for the metallic oxyds. — A. 
 
OF CHEMISTRY. 
 
 223 
 
 Sect. XV . — Obfervations upon Sulphurous Acid, 
 and its Combinations . 
 
 The fuiphurous acid is formed by the union 
 of oxygen with fulphur by a lefTer degree of o- 
 xygenation than the fulphuric acid. It is pro- 
 curable either by burning fulphur flowly, or by 
 diddling fulphuric acid from filver, antimony, 
 lead, mercury, or charcoal ; by which operation 
 a part of the oxygen quits the acid, and unites 
 to thefe oxydable bafes, and the acid palfes over 
 in the fuiphurous date of oxygenation. This 
 acid, in the common preflure and tempera- 
 ture of the air, can only exift in form of gas ; 
 but it appears, from the experiments of Mr 
 Clouet, that, in a very low temperature, it con- 
 denfes, and becomes fluid. Water abforbs a 
 great deal more of this gas than of carbonic a- 
 cid gas, but much lefs than it does of muriatic 
 acid gas. 
 
 That the metals cannot be diiTolved in acids 
 without being previoufly oxy dated, or by pro- 
 curing oxygen, for that purpofe, from the acids 
 during folution, is a general and well eftablifh- 
 ed fa£t, which I have perhaps repeated too of- 
 ten. Hence, as fuiphurous acid is already de- 
 prived of great part of the oxygen necefiary for 
 forming the fulphuric acid, it is more difpofed 
 
224 
 
 ELEMENTS 
 
 to recover oxygen, than to furnifh it to the 
 greateft part of the metals ; and, for this reafon, 
 it cannot diffolve them, unlefs previoufly oxyda- 
 ted by other means. From the fame principle 
 it is that the metallic oxyds diffolve without ef- 
 fervefcence, and with great facility, in fulphu- 
 rous acid. This acid, like the muriatic, has even 
 the property of diffolving metallic oxyds furchar- 
 ged with oxygn, and confequently infoluble in 
 fulphuric acid, and in this way forms true ful- 
 phats. Hence we might be led to conclude that 
 there are no metallic fulphites, were it not that the 
 phenomena which accompany the folution of 
 iron, mercury, and fome other metals, convince 
 us that thefe metallic fubftances are fufceptible 
 of two degrees of oxydation, during their folu- 
 tion in acids. Hence the neutral fait in which 
 the metal is lead oxydated muft be named JuU 
 phite , and that in which it is fully oxydated muff 
 be called fulphat . It is yet unknown whether 
 this diftin&ion is applicable to any of the metal- 
 lic fulphats, except thofe of iron and mercury. 
 
 Table 
 
OF CHEMISTRY, 
 
 225 
 
 Table of the Combinations of Phofphorous and 
 Phofphoric Acids , with the Salifiable Bafes > in 
 the Order of Affinity . 
 
 Names of the Nasnes of the Neutral Salts formed hy 
 
 Bafes . Phofphorous Acid \ Phofphoric Acid . 
 
 Lime 
 
 Phofphites off 
 
 Phofphats of 
 
 lime 
 
 lime. 
 
 Barytes 
 
 barytes 
 
 barytes. 
 
 Magnelia 
 
 roagnefia 
 
 magnefia. 
 
 Potafli 
 
 potalh 
 
 potafh. 
 
 Soda 
 
 foda 
 
 foda. 
 
 Ammoniac 
 
 ammoniac 
 
 ammoniac. 
 
 Argil l 
 Oxyds of * 
 
 argill 
 
 argill. 
 
 zinc 
 
 zinc 
 
 zinc. 
 
 iron 
 
 iron 
 
 iron. 
 
 manganefe 
 
 manganefe 
 
 manganefe* 
 
 cobalt 
 
 cobalt 
 
 cobalt. 
 
 nickel 
 
 nickel 
 
 nickel. 
 
 lead 
 
 lead 
 
 lead. 
 
 tin 
 
 tin 
 
 tin. 
 
 copper 
 
 copper 
 
 copper. 
 
 bifmuth 
 
 bifmuth 
 
 bifmuth. 
 
 antimony 
 
 antimohy 
 
 antimony. 
 
 arfenic 
 
 arfenic 
 
 arfenic. 
 
 mercury 
 
 mercury 
 
 mercury. 
 
 filver 
 
 filver 
 
 filver. 
 
 gold 
 
 gold. 
 
 gold. 
 
 platina 
 
 platina 
 
 platina. 
 
 * The exigence of metallic phofphites fuppofes that 
 metals are fufceptible of folution in phofphoric acid at 
 different degrees of oxygenation, which is not yet af* 
 certained. — A. 
 
 f All the phofphites were unknown till lately, and 
 confequently have not hitherto received names. — A. 
 
 J The greater part of the phofphats were only difco* 
 vered of late ? and have not yet been named. — -A. 
 
 F f 
 
 Sect, 
 
ELEMENTS 
 
 .2 2 6 
 
 .Sect. XVI. — Obfervations upon Phofphorous and 
 Pbofporic Acids , and their Combinations . 
 
 Under the article Phofphorus, Part II. Se&. 
 X. we have already given a hiflory of the dis- 
 covery of that fingular fubflance, with fome ob- 
 fervations upon the mode* of its exiftence in ve- 
 getable and animal bodies. The bell method 
 of obtaining this acid in a (late of purity is by 
 burning well purified phofphorus under bell- 
 glafies, moiftened on the infide with diftilled 
 water ; during combuflion it abforbs twice 
 and a half its weight of oxygen ; fo that ioo 
 parts of phofphoric acid is compofed of 284- 
 parts of phofphorus united to 7 if parts of oxy- 
 gen. This acid may be obtained concrete, in 
 form of white flakes, which greedily attract the 
 moifture of the air, by burning phofphorus in a 
 dry glafs over mercury. 
 
 To obtain phofphorous acid, which is phof- 
 phorus lefs oxygenated than in the date 
 .of phofphoric acid, the phofphorus muff be 
 burnt by a very flow fpontaneous combuflion 
 over a glafs- funnel leading into a cryftal phial ; 
 after a few days, the phofphorus is found oxy- 
 genated, and the phofphorous acid, in propor- 
 tion as it forms, has attracted moiiture from the 
 air, and dropped into the phial. The phofpho- 
 rous 
 
'OF CHEMISTRY. 
 
 227 
 
 I 
 
 I'oys acid is readily changed into phofphoric acid 
 by expofure for a long time to the free air ; it 
 abforbs oxygen from the air, and becomes fully 
 oxygenated. 
 
 As phofphorus has a fufficient affinity for oxy- 
 gen to attraft it from the nitric and muriatic a- 
 cids, wc may form phofphoric acid, by means 
 of thefe acids, in a very Ample and cheap man- 
 ner. Fill a tubulated receiver, half full of con- 
 centrated nitric acid, and heat it gently, then 
 throw in fmall pieces of phofphorus through the 
 tube, thefe are diifolved with effervefcence and 
 red fumes of nitrous gas fly off ; add phofphorus 
 fo long as it will difl'olve, and then increafe the 
 fire under the retort to drive off the laff particles 
 of nitric acid ; phofphoric acid, partly fluid and 
 partly concrete* remains in the retort. 
 
 m 
 
 1 ABLE 
 
ELEMENTS 
 
 228 
 
 Table of the Combinations of Carbonic Acid , with the 
 Salifiable Safes 5 in the Order of Affinity . 
 
 Refulting Neutral Salts , 
 
 Names of Bafss . New Nomenclature . Old Nomenclature . 
 
 Barytes 
 
 Carbonats of * 
 barytes 
 
 C Aerated or effervefeent heavy 
 4 earth. 
 
 Lime 
 
 lime 
 
 C Chalk, calcareous fpar, 
 
 4 Aerated calcareous earth. 
 
 ( Effervefcing or aerated fixed ve« 
 
 Potafh 
 
 potafh 
 
 X getable alkali, mephitis of po* 
 ( tafh. 
 
 Soda 
 
 foda 
 
 C Aerated or efFervefcingfixed mi- 
 
 £ neral alkali, mephitic foda. 
 
 Magnefia 
 
 magnefia 
 
 C Aerated, effervefcing, mild, or 
 ( • mephitic magnefia. 
 
 Ammoniac 
 
 ammoniac 
 
 C Aerated, effervefcing, mild, or 
 4 mephitic volatile alkali. 
 
 Argill 
 Oxyds of 
 zinc 
 
 argill 
 
 C Aerated or effervefcing argilla* 
 4 ceous earth, or earth of alum. 
 
 zinc 
 
 C Zinc fpar, mephitic or aerated 
 
 
 4 zinc. 
 
 iron 
 
 iron 
 
 C Sparry iron ore, mephitic or ae- 
 ^ rated iron. 
 
 jnanganefe 
 
 manga nefe 
 
 Aerated manganefe. 
 
 cobalt 
 
 cobalt 
 
 Aerated cobalt. 
 
 nickel 
 
 nickel 
 
 Aerated nickel. 
 
 lead 
 
 lead 
 
 Sparry lead-ore, or aerated lead. 
 
 tin 
 
 tin 
 
 Aerated tin. 
 
 copper 
 
 copper 
 
 Aerated copper. 
 
 bifmuth 
 
 bifmuth 
 
 Aerated bifmuth. 
 
 antimony 
 
 antimony 
 
 Aerated antimony. 
 
 arfenic 
 
 arfenic 
 
 Aerated arfenic. 
 
 mercury 
 
 mercury 
 
 Aerated mercury. 
 
 filver 
 
 filver 
 
 Aerated filver. 
 
 gold 
 
 gold 
 
 Aerated gold. 
 
 platina 
 
 platina 
 
 Aerated platina. 
 
 '* As thefe falts have only been underftood of late, they 
 have not, properly fpeaking, any old names. Mr Morveau, 
 in the Firft Volume of the Encyclopedia, calls them Mepbites ; 
 Mr Bergman gives them the name of aerated ; and Mr de 
 Fourcroy, who calls the carbonic acid chalky acid , gives them 
 the name of chalks*—* A, 
 
OF CHEMISTRY. 
 
 229 
 
 Sect. XVII. — Obfervations upon Ccfrbonic Acid , 
 
 Of all the known acids, the carbonic is the 
 jnoft abundant in nature ; it exifts ready form- 
 ed in chalk, marble, and all the calcareous 
 Hones, in which it is neutralized by a particu- 
 lar earth called lime. To difengage it from this 
 combination, nothing more is requifite than to 
 add fome fulphuric acid, or any other which has 
 a ftronger affinity for lime ; a brifk effervef- 
 cence enfues, which is produced by the difen- 
 gagement of the carbonic acid which affumes 
 the Hate of gas immediately upon being fet free. 
 This gas, incapable of being condenfed into the 
 folid or liquid form by any degree of cold or of 
 preffure hitherto known, unites to about its own 
 bulk of water, and thereby forms a very weak 
 acid. It may likewife be obtained in great a- 
 bundance from faccharine matter in fermenta- 
 tion, but is then contaminated by a fmall por- 
 tion of alkohol which it holds in folution. 
 
 As charcoal is the radical of this acid, we 
 may form it artificially, by burning charcoal in 
 oxygen gas, or by combining charcoal and me- 
 tallic oxyds in proper proportions ; the oxygen 
 
 of the oxyd combines with the charcoal, form- 
 ing 
 
 and its Combinations. 
 
230 ELEMENT S 
 
 zng carbonic acid gas, and the metal being left 
 free, recovers its metallic or reguline form. 
 
 We are indebted for our firft knowledge of 
 this acid to Dr Black, before whole time its pro- 
 perty of remaining always in the ftate of gas 
 had made it to elude the refearches of chemiftry. 
 
 It would be a mofl valuable difcovery to fo- 
 ciety, if we could decompofe this gas by any 
 cheap procefs, as by that means we might ob- 
 tain, for economical purpofes, the immenfe 
 {tore of charcoal contained in calcareous earths, 
 marbles, limeftones, &c. This cannot be ef- 
 fected by fingle affinity, becaufe, to decompofe 
 the carbonic acid, it requires a fubftance as 
 combuftible as charcoal itfelf, fo that we ffiould 
 only make an exchange of one combuftible bo- 
 dy for another not more valuable ; but it may 
 poffibly be accompliffied by double affinity, fince 
 this procefs is fo readily performed by Nature, 
 during vegetation, from the moft common ma- 
 terials. 
 
 Table 
 
/ 
 
 OF CHEMISTRY. 
 
 231 
 
 Table of the Combinations of Muriatic Acid, with the 
 Salifiable Bafes, in the Order of Affinity, 
 
 Refulting Neutral Salts . 
 
 Names of the 
 ... bafes. 
 
 New nomenclature . 
 
 Old nomenclature. 
 
 fj Muriat of 
 
 Bar y £es - barytes 
 
 5 Sea-falt, having bafe of 
 X heavy earth. 
 
 
 
 ("Febrifuge fait of Sylvius. 
 
 Potafh 
 
 potafh 
 
 < Muriated vegetable fixed 
 ( alkali. 
 
 Soda 
 
 foda 
 
 Sea-falt. 
 
 Lime 
 
 lime 
 
 C Muriated lime. 
 X Oil of lime. 
 
 jVIagnefia 
 
 magnefia 
 
 \ Marine Epfom fait. 
 X Muriated magnefia. 
 
 Ammoniac 
 
 ammoniac 
 
 Sal ammoniac. 
 ('Muriated alum, fea-falt 
 
 Argill 
 
 argill 
 
 < with bafe of earth of a- 
 ^ lum. 
 
 Oxyd of 
 
 zinc 
 
 C Sea-falt of, or muriatic 
 
 zinc 
 
 X zinc. 
 
 iron 
 
 iron 
 
 C Salt of iron, Martial fea« 
 i&It. 
 
 manganefe 
 
 manganefe 
 
 Sea frit of manganefe. 
 
 cobalt 
 
 cobalt 
 
 Sea-falt of cobalt. 
 
 nickel 
 
 nickel 
 
 Sea-falt of nickel. 
 
 lead 
 
 lead 
 
 5 Horny-Jead. Plumbum 
 
 
 X corneum. 
 
 tin - 
 
 £ fmoaking of tin 
 [ folid of tin 
 
 r.Smoaking liquor of Li- 
 *\ bavius. 
 
 C Solid butter of tin. 
 
 copper 
 
 copper 
 
 Sea-falt of copper. 
 
 bifmuth 
 
 bifmuth 
 
 Sea-falt of bifmuth. 
 
 antimony 
 
 antimony 
 
 Sea-falt of antimony. 
 
 %rfenic 
 
 a^lenic 
 
 Sea-falt of arfenic. 
 
 f 
 
 mercury <[ 
 
 fweet of mercury 
 
 filver 
 
 gold 
 
 platina 
 
 j ^ corrofive of mercury 
 
 filver 
 
 gold 
 
 platina 
 
 C Sweet fublimate of mer- 
 < cury, calomel, aquila 
 C alba. 
 
 5 Corrofive fublimate of 
 (_ mercury. 
 
 ? Horny lilver, argentum 
 X corneum, iuna cornea. 
 Sea- fait of gold- 
 Sea-falt of platina. 
 
 Table 
 
ELEMENTS 
 
 V32 
 
 Table Of the Combinations of Oxygenated Muri - 
 tic Acid , with the Salifiable Bafes , in the Or- 
 der of Affinity . 
 
 Names of the Neutral Salts By 
 
 Names of the Bafes . 
 
 the new Nomenclature . 
 
 Oxygenated muriat of 
 
 Barytes 
 
 barytes. 
 
 Potafh 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Lime 
 
 lime. 
 
 Magnefia 
 
 magnefia. 
 
 Argill 
 
 argill. 
 
 Oxyd of 
 
 • 
 
 zinc 
 
 zinc. 
 
 iron 
 
 iron. 
 
 manganefe 
 
 manganefe. 
 
 cobalt 
 
 cobalt. 
 
 nickel 
 
 nickel. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 copper 
 
 copper. 
 
 bifmuth 
 
 bifmuth. 
 
 antimony 
 
 antimony. 
 
 arfenic 
 
 arfenic. 
 
 mercury 
 
 mercury. 
 
 filver 
 
 filver. 
 
 gold 
 
 gold. 
 
 platina 
 
 platina. 
 
 This order of falts, entirely unknown to the ancient 
 
 chemifts, was difcovered in 1786 by Mr Berthollet, 
 —A, 
 
 Sect, 
 
OF CHEMISTRY, 
 
 233 
 
 Sect. XIX . — Obfervations upon Muriatic and 
 Oxygenated Muriatic Acids , and their Combi - 
 nations . 
 
 Muriatic acid is very abundant in the mine- 
 ral kingdom naturally combined with different 
 falifiabie bafes, efpecially with foda, lime, and 
 magnefia. In fea-water, and the water of feve- 
 ral lakes, it is combined with thefe three bafes, 
 and in mines of rock-falt it is chiefly united to 
 l'oda. This acid does not appear to have been 
 hitherto decompofed in any chemical experi- 
 ment ; fo that we have no idea whatever of the 
 nature of its radical, and only conclude, from a- 
 nalogy with the other acids, that it contains o- 
 xygen as its acidifying principle. Mr Berthol- 
 let fufpe&s the radical to be of a metallic na- 
 ture , but, as Nature appears to form this acid 
 daily, in inhabited places, by combining miaf- 
 mata with aeriform fluids, this muff neceffarily 
 fuppofe a metallic gas to exift in the atmo- 
 fphere, which is certainly not impofiible, but 
 cannot be admitted without proof. 
 
 The muriatic acid has only a moderate adhe- 
 rence to the falifiabie bafes, and can readily 
 be driven from its combination with thefe by 
 fulphuric acid. Other acids, as the .nitric, for 
 inffance, may anfwer the fame purpofe ; but nb 
 trie acid being volatile, would mix, during db 
 G g ffillation. 
 
234 
 
 ELEMENTS 
 
 filiation, with the muriatic. About one part 
 of fulphuric acid is fufficient to decompofe two 
 parts of decrepitated fea-falt. This operation is 
 performed in a tubulated retort, having Woulfe’s 
 apparatus, (PI. IV. Fig. i.), adapted to it. When 
 all the junftures are properly lured, the fea-falt 
 is put into the retort through the tube, the ful- 
 phurk acid is poured on, and the opening im- 
 mediately clofed with its ground cryftal Hopper. 
 As the muriatic acid can only fubfift in the gaf* 
 feous form in the ordinary temperature, we 
 could not condenfe it without the prefence of 
 water. Hence the ufe of the water with which 
 the bottles in Woulfe’s apparatus are half filled ; 
 the muriatic acid gas, driven off from the fea- 
 falt in the retort, combines with the water, and 
 forms what the old chemifts called fmoaking fpl - 
 rit of fait , or Glauber’s fpirit of fea-falt > which 
 we now name muriatic acid . 
 
 The acid obtained by the above procefs is Hill 
 capable of combining with a farther dofe of o- 
 xygen, by being diftilled from the oxyds of 
 manganefe, lead, or mercury, and the refulting 
 acid, which we name oxygenated muriatic acid , can 
 only, like the former, exift in the gaffeous form, 
 and is abforbed, in a much fmaller quantity by 
 water. When the impregnation of water with 
 this gas is pufhed beyond a certain point, the fu- 
 perabundant acid precipitates to the bottom of 
 the veffels in a concrete form. Mr Berthollet has 
 
 fhowxi 
 
OF CHEMISTRY. 
 
 2 35 
 
 fhown that this acid is capable of combining 
 with a great number of the falifiable bafes ; the 
 neutral falts which refult from this union are 
 fufceptible of deflagrating with charcoal, and 
 many of the metallic fubftances ; thefe deflagra- 
 tions are very violent and dangerous, owing to 
 the great quantity of caloric which the oxygen 
 carries alongft with it into the compofition of 
 oxygenated muriatic acid. 
 
 Table 
 
23*5 
 
 ELEMENTS 
 
 T^ele of the Combinations of Nitre-muriatic Acid 
 with the Salifiable Bafes , in the Order of Af- 
 finity, fo far as is known . 
 
 Names of the Bafes . 
 
 Names of the Neutral Salts, 
 
 Argill 
 
 Nitro-muriat of ai 
 
 Ammoniac 
 
 ammoniac. 
 
 Oxyd of 
 
 antimony 
 
 antimony. 
 
 filver 
 
 , filver. 
 
 arfenic 
 
 arfenic. 
 
 Barytes 
 
 barytes. 
 
 Oxyd of 
 
 bifmuth 
 
 bifmuth. 
 
 Lime 
 
 lime. 
 
 Oxyd of 
 
 cobalt 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 tin 
 
 tin. 
 
 iron 
 
 iron. 
 
 Magnefia 
 
 magnefia. 
 
 Oxyd of 
 
 manganefe 
 
 manganefe. 
 
 mercury 
 
 mercury. 
 
 molybdena 
 
 molybdena 
 
 nickel 
 
 nickel. 
 
 goid 
 
 gold. 
 
 platina 
 
 platina. 
 
 lead 
 
 lead 
 
 Potaili 
 
 potafli. 
 
 Soda 
 
 foda. 
 
 Oxyd of 
 
 tungftein 
 
 tunglteui. 
 
 zinc 
 
 zinc. 
 
 Note — Moft of thefe combinations, efpecially thofe 
 with the earths and alkalies, have been little examined, 
 and we are yet to learn whether they form a mixed 
 fall in which the compound radical remains combined* 
 or if the two acids feparate, to form two diflinft neu* 
 tral falts. — A. 
 
OF CHEMISTRY. 
 
 *3? 
 
 Sect. 'XCL.-~Obfervations upon the Nitre- Mur ia - 
 tic Acid> and its Combinations . 
 
 The nitro-muriatic acid, formerly called a- 
 qua regia , is formed by a mixture of nitric and 
 muriatic acids ; the radicals of thefe two acids 
 combine together, and form a compound bafe, 
 from which an acid is produced, having proper- 
 ties peculiar to itfelf, and diftinCt from thofe of 
 all other acids, efpecially the property of diffol- 
 ving gold and platina. 
 
 In diffolutions of metals in this acid, as in all 
 other acids, the metais are firfl oxydated by at- 
 tracting a part of the oxygen from the com- 
 pound radical. This occafions a difengage- 
 ment of a particular fpecies of gas not hitherto 
 deferibed, which may be called nitro- muriatic gas ; 
 it has a very difagreeable fmell, and is fatal to 
 animal life when refpired ; it attacks iron, and 
 caufes it to ruft ; it is abforbed in confiderable 
 quantity by water, which thereby acquires fome 
 flight characters of acidity. I had occafion to 
 make thefe remarks during a courfe of experi- 
 ments upon platina, in which I diflblved a confi- 
 derable quantity of that metal in nitro-muriatic 
 acid. 
 
 I at firft fufpeCted that, in the mixture of ni- 
 tric and muriatic acids, the latter attracted a 
 
 part 
 
23S ELEMENTS 
 
 part of the oxygen from the former, and be- 
 came converted into oxygenated muriatic acid, 
 which gave it the property of diffolving gold ; 
 but feveral fads remain inexplicable upon this 
 fuppofition. Were it fo, we muft be able to 
 difengage nitrous gas by heating this acid, 
 which however does not fenfibly happen. From 
 thefe confiderations, I am led to adopt the opi- 
 nion of Mr Berthollet, and to confider nitro- 
 muriatic acid as a fingle acid, with a compound 
 f)afe or radical. 
 
 Tabls 
 
OF CHEMISTRY. 
 
 *39 
 
 Table of the Combinations of Fluoric Acid , with 
 the Salifiable Bafes 9 in the Order of Affinity . 
 
 Names of the Bafes . 
 
 Names of the Neutral S, 
 
 Lime 
 
 Fluat of lime. 
 
 Barytes 
 
 barytes. 
 
 Magnefia 
 
 magnefia. 
 
 Potafh 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Ammoniac 
 
 ammoniac* 
 
 Oxyd of 
 
 
 zinc 
 
 zinc. 
 
 manganefe 
 
 manganefe. 
 
 iron 
 
 iron. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 cobalt 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 nickel 
 
 nickel. 
 
 arfenic 
 
 arfenic. 
 
 bifmuth 
 
 bifmuth. 
 
 mercury 
 
 mercury. 
 
 filver 
 
 filver. 
 
 gold 
 
 gold. 
 
 platina 
 
 platina. 
 
 And by the dry way, 
 Argill Fluat of argil!. 
 
 Note . — Thefe combinations were entirely unknown 
 to the old chemifts, and confequently have no names 
 in the old nomenclature.— A. 
 
 Sect. 
 
ELEMENTS 
 
 240 
 
 Sect. XXL — Obfervations upon the Fluoric Acid , 
 and its Combinations . 
 
 Fluoric exifts ready formed by Nature in the 
 fluoric fpars *, combined with calcareous earth, 
 fo as to form an infoluble neutral fait. To ob- 
 tain it difengaged from that combination, fluor 
 fpar, or fluat of lime, is put into a leaden re- 
 tort, with a proper quantity of fulphuric acid, a 
 recipient likewife of lead, half full of water, is 
 adapted, and fire is applied to the retort. The 
 fulphuric acid, from its greater affinity, expels 
 the fluoric acid which pafles over and is abforb- 
 ed by the water in the receiver. As fluoric a- 
 cid is naturally in the gafleous form in the or- 
 dinary temperature, we can receive it in a pneu- 
 mato-chemical apparatus over mercury. We 
 are obliged to employ metallic veffels in this pro- 
 cefs, becaufe fluoric acid diffolves glafs and filici- 
 ous earth, and even renders thefe bodies volatile, 
 carrying them over with itfelf in diftillation in 
 the gafleous form. 
 
 We are indebted to Mr Margraff for our firfl 
 acquaintance with this acid, though, as he could 
 never procure it free from combination with a 
 confiderabie quantity of filicious earth, he was 
 
 ignorant 
 
 * Commonly called Dtrhjhire fpar:. — E. 
 
OF CHEMISTRY* e 4 t 
 
 ignorant of its being an acid fui generis. The 
 Duke de Liancourt, under the name of Mr 
 Boulanger, confiderably increafed our know- 
 ledge of its properties ; and Mr Scheele feems to 
 have exhaufted the fubjed. The only thing re- 
 maining is to endeavour to difcover the nature 
 of the fluoric radical, of which we cannot hi- 
 therto form any ideas, as the acid does not ap- 
 pear to have been decompofed in any experi- 
 ment. It is only by means of compound affini- 
 ty that experiments ought to be made with this 
 view, with any probability of fuccefs. 
 
 ' H h 
 
 Table 
 
ELEMENTS 
 
 Table of the Combinations of Boracic Acid, with 
 the Salifiable Bafes , in the Order of Affinity 
 
 Bafes . 
 
 Neutral Salts. 
 
 Lime 
 
 Borat of lime. 
 
 Barytes 
 
 barytes. 
 
 Magnefia 
 
 magnefia. 
 
 Potalh 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Ammoniac 
 
 ammoniac. 
 
 Oxyd of 
 
 
 zinc 
 
 zinc. 
 
 iron 
 
 iron. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 cobalt 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 nickel 
 
 nickel. 
 
 mercury 
 
 mercury. 
 
 Argill 
 
 argill. 
 
 Note . — Moft of thefe combinations were neither known 
 nor named by the old chemifts. The boracic acid was 
 formerly called fedative fait , and its compounds borax, 
 with bafe of fixed vegetable alkali, &c . — A. 
 
 Sect, 
 
OF CHEMISTRY. 
 
 243 
 
 Sect. XXII. — Obfervations upon Boracic Acid 
 * and its Combinations . 
 
 This is a concrete acid, extra&ed from a fait 
 procured from India called borax or tincall. Al- 
 though borax has been very long employed in 
 the arts, we have as yet very imperfect know- 
 ledge of its origin, and of the methods by which 
 it is extradted and purified ; there is reafon to 
 
 I believe it to be a native fait, found in the earth 
 in certain parts of the ead, and in the water of 
 fome lakes. The whole trade of borax is in 
 the hands of the Dutch, who have been exclu- 
 fively polfefied of the art of purifying it till very 
 lately, that Melfrs 1 /Eguillier of Paris have ri- 
 valled them in the manufacture ; but the pro- 
 cefs dill remains a fecret to the world. 
 
 By chemical analyfis we learn that borax is a 
 neutral fait with excefs of bafe, confiding of fo- 
 da, partly faturated with a peculiar acid long 
 ealled Homberg’s fedative fait , now the boracic a- 
 \ cid . This acid is found in an uncombined date 
 in the waters of certain lakes. That of Cherchi- 
 ais in Italy contains 94^ grains in each pint of 
 water. 
 
 To obtain boracic acid, dLTolve fome borax 
 in boiling water, filtrate the folution, and add 
 fulphuric acid, or any other having greater affi- 
 
 nity 
 
344 
 
 ELEMENTS 
 
 nity to foda than the boracic acid ; this lat- 
 ter acid is feparated, and is procured in a 
 cryflalline form by cooling. This acid was 
 long confidered as being formed during the 
 procefs by which it is obtained, and was con- 
 fequently fuppofed to differ according to the 
 nature of the acid employed in feparating it 
 from the foda ; but it is now univerfally ac- 
 knowledged that it is identically the fame acid, 
 in whatever way procured, provided it be pro-i 
 perly purified from mixture of other acids, by 
 walking, and by repeated folution and criftalli- 
 zation. It is foluble both in water and alkohol, 
 and has the property of communicating a green 
 colour to the flame of that fpirit. This circum- 
 ftance led to a fufpicion of its containing copper, 
 which is not confirmed by any decifive experi- 
 meitt. On the contrary, if it contain any of 
 that metal, it muft only be confidered as an ac- 
 cidental mixture. It combines with the falifi- 
 able bafes in the humid way ; and though, in 
 this manner, it is incapable of dilfolving any of 
 the metals dire&ly, this combination is readily 
 affe&ed by compound affinity. 
 
 The Table prefents its combinations in the 
 order of affinity in the humid way ; but there 
 is a confiderabie change in the order when we 
 operate via ficca ; for, in that cafe, argil!, 
 though the laft in our lift, muft be placed im- 
 mediately after foda. 
 
 The 
 
OF CHEMISTRY. 
 
 245 
 
 The boracic radical is hitherto unknown s 
 no experiments having as yet been able to de- 
 compofe the acid ; we conclude, from analogy 
 with the other acids, that oxygen exifls in its 
 compofition as the acidifying principle. 
 
 Table 
 
ELEMENTS 
 
 246 
 
 Table of the Combinations of Arfeniac Acid , with 
 the Salifiable Bafts, in the Order of Affinity . 
 
 Bafes. 
 
 Neutral Salts . 
 
 Lime 
 
 Arfeniat of lime. 
 
 Barytes 
 
 barytes. 
 
 Magnefia 
 
 magnefia. 
 
 Potafh 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Ammoniac 
 
 ammoniac. 
 
 Oxyd of 
 
 
 zinc 
 
 zinc. 
 
 manganefe 
 
 manganefe. 
 
 iron 
 
 iron. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 cobalt 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 nickel 
 
 nickel. 
 
 bifmuth 
 
 bifmuth. 
 
 mercury 
 
 mercury. 
 
 antimony 
 
 antimony. 
 
 fi lver 
 
 filver. 
 
 gold 
 
 gold. 
 
 platina 
 
 platina. 
 
 Argill 
 
 argill. 
 
 Note . — This order of falts was entirely unknown to 
 the antient chemifts. Mr Macquer, in 1746, difcover- 
 ed the combinations of arfeniac acid with potafh and 
 foda, to which he gave the name of arfenical neutral 
 Jalts . — A. 
 
 Sect, 
 
OF CHEMISTRY. 
 
 n? 
 
 Sect. XXIII . — Obfervations upon Arfeniac Acid , 
 and its Combinations . 
 
 In the Collections of the Academy for 174 6, 
 Mr Macquer fhovvs that, when a mixture of 
 white oxyd of arfenic and nitre are fubjeCted to 
 the aCtion of a ftrong fire, a neutral fait is ob- 
 tained, w r hich he calls neutral fait of arfenic. At 
 that time, the caufe of this fingular phenome- 
 non, in which a metal aCts the part of an acid, 
 was quite unknown ; but more modern ex- 
 periments teach that, during this procefs, the 
 arfenic becomes oxygenated, by carrying off the 
 oxygen of the nitric acid ; it is thus converted 
 into a real acid, and combines with the potafh. 
 There are other methods now known for oxy- 
 genating arfenic, and obtaining its acid free 
 from combination. The moft Ample and mod: 
 effeClual of thefe is as follows : Diffolve white 
 oxyd of arfenic in three parts, by weight, of 
 muriatic acid ; to this folution, in a boiling 
 Rate, add two parts of nitric acid, and evapo- 
 rate to drynefs. In this procefs the nitric acid is 
 decompofed, its oxygen unites with the oxyd of 
 arfenic, and converts it into an acid, and the 
 nitrous radical flies off in the date of nitrous 
 gas ; whilft the muriatic acid is converted by 
 the heat into muriatic acid gas, and may be col- 
 lected in proper veffels. The arfeniac acid is en- 
 tirely 
 
 , 
 
 ‘ 
 
fc 4 s ELEMENTS 
 
 tirely freed from the other acids employed during 
 the procefs by heating it in a crucible till it be- 
 gins to grow red ; what remains is pure con- 
 crete arfeniac acid. 
 
 Mr Scheele’s procefs, which was repeated 
 with great fuccefs by Mr Morveau, in the labo- 
 ratory at Dijon, is as follows ; Diftil muriatic a- 
 cid from the black oxyd of manganefe, this con- 
 verts it into oxygenated muriatic acid, by car- 
 rying off the oxygen from the manganefe, re- 
 ceive this in a recipient containing white oxyd 
 of arfenic, covered by a little diftilled water ; 
 the arfenic decompofes the oxygenated muriatic 
 acid, by carrying off its fuperfaturation of oxy- 
 gen, the arfenic is converted into arfeniac acid, 
 and the oxygenated muriatic acid is brought 
 back to the ftate of common muriatic acid. 
 The two acids are feparated by diftillation, with 
 a gentle heat increafed towards the end of the 
 operation, the muriatic acid paffes over, and the 
 arfeniac acid remains behind in a white concrete 
 form. 
 
 The arfeniac acid is confiderably lefs volatile 
 than white oxyd of arfenic ; it often contains 
 white oxyd of arfenic in folution, owing to 
 its not being fufficiently oxygenated ; this is 
 prevented by continuing to add nitrous acid, as 
 in the former procefs, till no more nitrous 
 gas is produced. From all thefe obferva- 
 tions I would give the following definition of 
 
 arfeniac 
 
OF CHEMISTRY. 
 
 249 
 
 srfeniac acid. It is a white concrete metallic 
 acid, formed by the combination of arfenic with 
 oxygen, fixed in a red heat, foluble in tvater, 
 and capable of combining with many of the 
 falifiable bafes. 
 
 Sect. XXIV. — Obfervations upon Molybdic A - 
 cid, and its Combinations with Acidifiable Ba~ 
 
 fes *. 
 
 Molybdena is a particular metallic body, ca- 
 pable of being oxygenated, fo far as to become 
 a true concrete acid f. For this purpofe, one 
 part ore of molybdena, which is a natural ful- 
 phuret of that metal, is put into a retort, with 
 five or fix parts nitric acid, diluted with a quar- 
 ter of its weight of water, and heat is applied to 
 the retort ; the oxygen of the nitric acid ads 
 both upon the molybdena and the fulphur, con- 
 verting the one into molybdic, and the other 
 into fulphuric acid ; pour on frefh quantities of 
 nitric acid fo long as any red fumes of nitrous 
 I i gas 
 
 * I have not added the Table of thefe combinations, 
 as the order of their affinity is entirely unknown ; they 
 are called molybdats of argil , antimony , potajhy &c. — E. 
 
 f This acid was difcovered by Mr Scheele, to whom 
 chemiftry is indebted for the difcovery of feveral other 
 acids.— -A. 
 
t S 0 ELEMENTS 
 
 gas efcape ; the molydbena is then oxygenated as 
 far as is poflible, and is found at the bottom of 
 the retort in a pulverulent form, refembling 
 chalk. It mull be walhed in warm water, to 
 feparate any adhering particles of fulphuric a- 
 cid ; and, as it is hardly foluble, we lofe very 
 little of it in this operation. All its combina- 
 tions with falifiable bafes were unknown to the 
 ancient chemifts. 
 
 Table 
 
OF CHEMISTRY. 
 
 «S< 
 
 Table of the Combinations of Tungflic Acid with 
 the Salifiable Bafes. 
 
 Bafes. Neutral Salts • 
 
 Lime Tungftat of lime. 
 
 Barytes 
 
 Magnefia 
 
 Potafh 
 
 Soda 
 
 Ammoniac 
 
 Argill 
 
 Oxyd of antimo- 
 ny *, &c. 
 
 barytes. 
 
 magnefia. 
 
 potafh. 
 
 foda. 
 
 ammoniac. 
 
 argili. 
 
 antimony f, &c. 
 
 Sect. XXV. — Obfervations upon Tungflic Acid> 
 and its Combinations . 
 
 Tungftein is a particular metal, the ore of 
 which has frequently been confounded with that 
 of tin. The fpecific gravity of this ore is to water 
 as 6 to i $ in its form of criflallization it re- 
 
 fembles 
 
 * The combinations with metallic oxyds were fet 
 down by Mr Lavoifier in alphabetical order ; their or- 
 der of affinity being unknown, I have omitted them, as 
 ferving no purpofe. — E. 
 
 f All thefe falts were unknown to the ancient che- 
 mifts. — A. 
 
*5* ELEMENTS 
 
 fembles the garnet, and varies in colour from a 
 pearl-white to yellow and reddifli ; it is found 
 in feveral parts of Saxony and Bohemia. The 
 mineral called Wolfram , which is frequent in the 
 mines of Cornwal, is likewife an ore of this 
 metal. In all thefe ores the metal is oxydated ; 
 and, in fome of them, it appears even to be o- 
 xygenated to the ftate of acid, being combined 
 with lime into a true tungftat of lime. 
 
 To obtain the acid free, mix one part of 
 ore of tungftein with four parts of carbonat of 
 potafti, and melt the mixture in a crucible, then 
 powder and pour on twelve parts of boiling 
 water, add rptric acid, and jhe tungftic acid pre- 
 cipitates in a concrete form. Afterwards, to 
 infure the complete oxygenation of the metal, 
 add more nitric acid, and evaporate to drynefs, 
 repeating this operation fo long as red fumes of 
 nitrous gas are produced. To procure tungftic 
 acid perfeftly pure, the fufion of the ore with 
 carbonat of potafh muft be made in a crucible 
 of platina, otherwife the earth of the common 
 crucibles will mix with the produ&s, and adul- 
 terate the acid. 
 
 Table 
 
OF CHEMISTRY. 
 
 *53 
 
 Table of the Combinations of Tartarous Acid, 
 with the Salifiable Bafes, in the Order of 
 
 Affinity. 
 
 Bafes , Neutral Salts . 
 
 Lime Tartarite of lime. 
 
 Barytes 
 
 Magnefia 
 
 Potafh 
 
 Soda 
 
 Ammoniac 
 Argill 
 Oxyd of 
 zinc 
 
 iron 
 
 manganefe 
 
 cobalt 
 
 nickel 
 
 lead 
 
 tin 
 
 copper 
 
 bifmuth 
 
 antimony 
 
 arfenic 
 
 filver 
 
 mercury 
 
 gold 
 
 platina 
 
 barytes. 
 
 magnefia. 
 
 potafh. 
 
 foda. 
 
 ammoniac. 
 
 argill. 
 
 zinc. 
 
 iron. 
 
 manganefe, 
 
 cobalt. 
 
 nickel. 
 
 lead. 
 
 tin. 
 
 copper. 
 
 bifmuth. 
 
 antimony, 
 
 arfenic. 
 
 filver. 
 
 mercury. 
 
 gold. 
 
 platina. 
 
 Ssci\ 
 
ELEMENTS 
 
 *$4 
 
 Sect. XXVI . — Obfervations upon Tartar ous A - 
 cid, and its Combinations . 
 
 Tartar, or the concretion which fixes to the 
 infide of veffels in which the fermentation of 
 wine is completed, is a well known fait, com- 
 pofed of a peculiar acid, united in confiderable 
 excels to potafh. Mr Scheele firfl pointed out 
 the method of obtaining this acid pure. Ha* 
 ving obferved that it has a greater affinity to 
 lime than to potafh, he dire&s us to proceed in 
 the following manner. Dilfolve purified tartar 
 in boiling water, and add a fufficient quantity 
 of lime till the acid be completely faturated. 
 The tartarite of lime which is formed, being al- 
 mofl infoluble in cold water, falls to the bottom, 
 and is feparated from the folution of potafh by 
 decantation ; it is afterwards wafhed in cold 
 water, and dried ; then pour on fome fulphuric 
 acid, diluted with eight or nine parts of water, 
 digeft for twelve hours in a gentle heat, fre- 
 quently ftirring the mixture ; the fulphuric acid 
 combines with the lime, and the tartarous acid 
 is left free. A fmail quantity of gas, not hi- 
 therto examined, is difengaged during this pro- 
 cefs. At the end of twelve hours, having de- 
 canted off the clear liquor, wafh the fulphat of 
 lime in cold water, which add to the decanted 
 
 liquor. 
 
OF CHEMISTRY. 
 
 *55 
 
 liquor, then evaporate the whole, and the tarta- 
 rous acid is obtained in a concrete form. Two 
 pounds of purified tartar, by means of from 
 eight to ten ounces of fulphuric acid, yield a- 
 bout eleven ounces of tartarous acid. 
 
 As the combuftible radical exifts in excefs, 
 or as the acid from tartar is not fully faturated 
 with oxygen, we call it tartarous acid , and the 
 neutral falts formed by its combinations with fa- 
 lifiable bafes tartarites. The bafe of the tarta^ 
 rous acid is a carbono-hydrous or hydro-carbo- 
 nous radical, lefs oxygenated than in the oxalic 
 acid ; and it would appear, from the experi- 
 ments of Mr Haffenfratz, that azote enters into 
 the compofition of the tartarous radical, even in 
 confiderable quantity. By oxygenating the tar- 
 tarous acid, it is convertible into oxalic, malic, 
 and acetous acids ; but it is probable the pro- 
 portions of hydrogen and charcoal in the radical 
 are changed during thefe converfions, and that 
 the difference between thefe acids does not alone 
 confifl in the different degrees of oxygenation. 
 
 The tartarous acid is fufceptible of two de- 
 grees of faturation in its combinations with the 
 fixed alkalies ; by one of thefe a fait is formed 
 with excefs of acid, improperly called cream of 
 tartar , which in our new nomenclature is na- 
 med acidulous tartarite of pot ajh ; by a fecond or 
 equal degree of faturation a perfe&ly neutral 
 fait is formed, formerly called vegetable fall , 
 
 which 
 
z S 6 ELEMENTS 
 
 which we name tartar ite of potajh . With foda 
 this acid forms tartarite of foda, formerly called 
 fal de Seignette , or fal polychrejl of RochelL 
 
 Sect. XXVII . — Obfervations upon Malic Acid , 
 and its Combinations with the Salifiable Bafes *♦ 
 
 The malic acid exifts ready formed in the 
 four juice of ripe and unripe apples, and many 
 other fruits, and is obtained as follows : Satu- 
 rate the juice of apples with potafh or foda, and 
 add a proper proportion of acetite of lead dif- 
 iolved in water ; a double decompofition takes 
 place, the malic acid combines with the oxyd 
 of lead and precipitates, being almofl: infoluble, 
 and the acetite of potafh or foda remains in the 
 liquor. The malat of lead being feparated by 
 decantation, is wafhed with cold water, and fome 
 dilute fulphuric acid is added ; this unites with 
 the lead into an infoluble fulphat, and the malic 
 acid remains free in the liquor. 
 
 This acid, which is found mixed with citric 
 and tartarous acid in a great number of fruits, 
 is a kind of medium between oxalic and ace- 
 tous 
 
 * I have omitted the Table, as the order of affinity 
 is unknown, and is given by Mr Lavoifier only in al- 
 phabetical order. All the combinations of malic acid 
 with falifiable bafes, which are named malats , were un-» 
 known to the ancient chemifts. — E. 
 
OF CHEMISTRY. 
 
 2 57 
 
 tous acids being more oxygenated than the for- 
 mer, and lefs fo than the latter. From this cir- 
 cumftance, Mr Hermbftadt calls it imperfeft vim 
 negar ; but it differs likewife from acetous acid, 
 by having rather more charcoal, and lefs hydro- 
 gen, in the compofition of its radical. 
 
 When an acid much diluted has been ufed in 
 the foregoing procefs, the liquor contains oxalic 
 as well as malic acid, and probably a little tar- 
 tarous, thefe are feparated by mixing lime-wa- 
 ter with the acids, oxalat, tartarite, and malat 
 of lime are produced ; the two former, being 
 infoluble, are precipitated, and the malat of 
 lime remains diffolved ; from this the pure ma- 
 lic acid is feparated by the acetite of lead, and 
 afterwards by fulphuric acid, as dire&ed above. 
 
 K k 
 
 Table 
 
258 ELEMENTS 
 
 >*-r y ' j r ' * f . 
 
 Table gf the Combinations of Citric Acid , with 
 the Salifiable Bafes , m the Order of Affinity** 
 
 Bafeu 
 
 Barytes 
 
 Lime 
 
 Magnefia 
 
 Potafh 
 
 Soda 
 
 Ammoniac 
 Oxyd of 
 zinc 
 
 manganefe 
 
 iron 
 
 lead 
 
 cobalt 
 
 copper 
 
 arfenic 
 
 mercury 
 
 antimony 
 
 filver 
 
 gold 
 
 platina 
 
 Argil! 
 
 Neutral Salts. 
 
 Citrat of barytes* 
 lime, 
 magnefia. 
 potafh. 
 fbda. 
 
 ammoniac* 
 
 zinc. 
 
 manganefe. 
 
 iron. 
 
 lead. 
 
 cobalt. 
 
 copper. 
 
 arfenic. 
 
 mercury. 
 
 antimony* 
 
 filver. 
 
 gold. 
 
 platina. 
 
 argill. 
 
 * Thefe combinations were unknown to the ancient 
 chemifts. The order of affinity of the falifiable bafes 
 with this acid was determined by Mr Bergman and by- 
 Mr de Breney of the Dijon Academy. — A, 
 
 Sect. 
 
OF CHEMISTRY. 
 
 259 
 
 SfCT. XXVIII . — Obfervatiom upon Citric Acid \ 
 and its Combinations . 
 
 The citric acid is procured by expreffion. 
 from lemons, and is found in the juices of many 
 other fruits mixed with malic acid. To obtain 
 it pure and concentrated, it is firft allowed to 
 depurate from the mucous part of the fruit by 
 long reft in a cool cellar, and is afterwards 
 concentrated by expofing it to the temperature 
 of 4 or 5 degrees below Zero, from 21 0 to 23 0 
 of Fahrenheit, the water is frozen, and the acid 
 remains liquid, reduced to about an eighth part 
 of its original bulk. A lower degree of cold 
 would occafion the acid to be engaged amongft 
 the ice, and render it difficultly feparable. This 
 procefs was pointed out by Mr Georgius. 
 
 It is more eafily obtained by faturating the 
 lemon-juice with lime, fo as to form a citrat 
 of lime, which is infoluble in water j wafn this 
 fait, and pour on a proper quantity of fulphu- 
 ric acid ; this forms a fulphat of lime, which 
 precipitates and leaves the citric acid free in the 
 liquor. 
 
 Tabm 
 
ELEMENTS 
 
 Table of the Combinations of Pyro-lignous Acid 
 with the Salifiable Bafes , in the Order of Af- 
 finity *. 
 
 Bafes . 
 
 Neutral Salts . 
 
 Lime Pyro-mucite of lime. 
 
 Barytes 
 
 barytes. 
 
 Potafti 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Magnefia 
 
 magnefia. 
 
 Ammoniac 
 
 ammoniac. 
 
 Oxyd of 
 zinc 
 
 zinc. 
 
 manganefc 
 
 manganefe. 
 
 iron 
 
 iron. 
 
 lead 
 
 lead 
 
 tin 
 
 tin. 
 
 cobalt 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 nickel 
 
 nickel. 
 
 arfenic 
 
 arfenic. 
 
 bifmuth 
 
 bifmuth. 
 
 mercury 
 
 mercury. 
 
 antimony 
 
 antimony. 
 
 fiiver 
 
 filver. 
 
 gold 
 
 gold. 
 
 piatina 
 
 piatina. 
 
 Argil! 
 
 argill. 
 
 * The above affinities were determined by Mefirs de 
 Morveau and Eloi Bouruer de Clervaux, Thefe com- 
 binations were entirely unknown till lately. — A. 
 
 Sect 
 
OF CHEMISTRY. 
 
 Sect. XXIX. — Obfervations upon Pyro-lignous 
 Acid , and its Combinations . 
 
 The ancient chemifts obferved that moft of 
 the woods, efpecially the more heavy and com- 
 pact ones, gave out a particular acid fpirit, by 
 diftillation, in a naked fire; but, before Mr 
 Goetling, who gives an account of his experi- 
 ments upon this fubjedt in Crell’s Chemical 
 Journal for 1 779, no one had ever made any 
 inquiry into its nature and j^goperties. This a- 
 cid appears to be the fame, whatever be the 
 wood it is procured from. When firft dif- 
 tilled, it is of a brown colour, and confidei ably 
 impregnated with charcoal and oil ; it is puri- 
 fied from thefe by a fecond diftillation. The py- 
 ro-lignous radical is chiefly compofed of hydro* 
 gen and charcoal. 
 
 Sect. XXX.- — Obfervations upon Pyro 4 artarous 
 
 Acid , and its Combinations with the Salifiable 
 
 Bafes *. 
 
 The name of Pyro-tartarous acid is given to a 
 dilute empyreumatic acid obtained from puri- 
 fied 
 
 * The order of affinity of the falifiabie bafes with 
 this acid is hitherto unknown. Mr Lavoifier, from its 
 
 fimila- 
 
* 6 * ELEMENTS 
 
 fied acidulous tartarite of potafli by diftillation 
 in a naked fire. To obtain it, let a retort be 
 half filled with powdered tartar, adapt a tubu- 
 lated recipient, having a bent tube communica- 
 ting with a bell glafs in a pneumato-chemical 
 apparatus ; by gradually railing the fire under 
 the retort, we obtain the pyro-tartarous acid 
 mixed with oil, which is feparated by means of 
 a funnel. A vaft quantity of carbonic acid gas 
 is difengaged during the diftillation. The acid 
 obtained by the above procefs is much contami- 
 nated with oil, which ought to be feparated 
 from it. Some authors advife to do this by a 
 fecond diftillation ; but the Dijon academicians 
 inform us, that this is attended with great dan- 
 ger from explofions which take place during the 
 procefs. 
 
 / 
 
 Table 
 
 fimilarity to pyro-lignous acid, fuppofes the order to 
 be the fame in both ; but, as this is not afcertained 
 by experiment, the table is omitted. All thefe combi- 
 nations, called Pyro'tartarites 9 were unknown til! 
 lately.— E. 
 
OF CHEMISTRY. $ 6 3 
 
 Table of the Combinations of Pyro-mucous Acid 9 
 with the Salifiable Bafes , in the Order of Affi- 
 nity *. 
 
 Bafes* Neutral Salts . 
 
 Potafh Pyro-mucite of potafh. 
 
 Soda 
 
 foda. 
 
 Barytes 
 
 barytes. 
 
 Lime 
 
 lime. 
 
 Magnefia 
 
 magnefia. 
 
 Ammoniac 
 
 ammoniac* 
 
 Argill 
 Oxyd of 
 
 argill. 
 
 zinc 
 
 zinc. 
 
 manganefe 
 
 manganefe, 
 
 iron 
 
 iron. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 cobait 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 nickel 
 
 nickel. 
 
 arfenic 
 
 arfenic. 
 
 bifmuth 
 
 bifmuth. 
 
 antimony 
 
 antimony. 
 
 * All thefe combinations were unknown to the an« 
 dent chemifts. — A. 
 
 Sect * 1 
 
efi4 ElfcMENtS 
 
 Sect. XXXI . — Obferudtions upon Pyro»muc$us 
 Acid , and its Combinations . 
 
 This acid is obtained by diftillation in a na- 
 ked fire from fugar, and all the faccharine bo- 
 dies ; and, as thefe fubftances fwell greatly in 
 the fire, it is neceffary to leave feven-eighths of 
 the retort empty. It is of a yellow colour, ver- 
 ging to red, and leaves a mark upon the Ikin, 
 which will not remove but alongft with the epi- 
 dermis. It may be procured lefs coloured, by 
 means of a fecond diftillation, and is concen- 
 trated by freezing, as is directed for the citric 
 acid. It is chiefly compofed of water and oil 
 {lightly oxygenated, and is convertible into oxa- 
 lic and malic acids by farther oxygenation with 
 the nitric acid. 
 
 It has been pretended that a large quantity of 
 gas is difengaged during the diftillation of this 
 acid, which is not the cafe if it be conducted 
 fiowly, by means of moderate heat. 
 
 Table 
 
OF CHEMISTRY, 265 
 
 Table of the Combinations of the Oxalic Acid , 
 with the Salifiable Bafes , in the Order of Affi« 
 nity *. 
 
 Bafes . 
 
 Neutral Salts . 
 
 Lime 
 
 Oxalat of lime. 
 
 , Barytes 
 
 barytes. 
 
 Magnefia 
 
 magnefia* 
 
 Potafh 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Ammoniac 
 
 ammoniac. 
 
 Argill 
 Oxyd of 
 
 argill. 
 
 zinc 
 
 zinc. 
 
 iron 
 
 iron. 
 
 manganefe 
 
 mangaiiefe. 
 
 cobalt 
 
 cobalt. 
 
 nickel 
 
 nickel. 
 
 lead 
 
 lead. 
 
 copper 
 
 copper. 
 
 bifmuth 
 
 bifmuth. 
 
 antimony 
 
 arfenic 
 
 antimony. 
 
 arfenic. 
 
 mercury 
 
 mercury. 
 
 filver 
 
 filver. 
 
 gold 
 
 gold. 
 
 platina 
 
 platina. 
 
 All unknown to the ancient chemifts. — A. 
 
 L 1 
 
 Sect, 
 
266 
 
 ELEMENT 3- 
 
 Sect. XXXII . — Obfervations upon Oxalic Acid , 
 and its Combinations . 
 
 The oxalic acid is moftly prepared in Swit- 
 zerland and Germany from the expreffed juice 
 of forrel, from which it criftallizes by being left 
 long at reft \ in this ftate it is partly faturated 
 with potato, forming a true acidulous oxalat of 
 potato, or fait with excefs of acid. To obtain 
 it pure, it muft be formed artificially by oxyge- 
 nating fugar, which feems to be the true oxalic 
 radical. Upon one part of fugar pour fix or 
 eight parts of nitric acid, and apply a gentle 
 heat ; a confiderable effervefcence takes place, 
 and a great quantity of nitrous gas is difenga- 
 ged \ the nitric acid is decompofed, and its oxy- 
 gen unites to the fugar : By allowing the liquor 
 to ftand at reft, criftals of pure oxalic acid are 
 formed, which muft be dried upon blotting pa- 
 per, to feparate any remaining portions of ni- 
 tric acid ; and, to enfure the purity of the acid, 
 diffolve the criftals in diftilled water, and crif- 
 tallize them afreto. 
 
 From the liquor remaining after the firft crif- 
 tallization of the oxalic acid we may obtain ma- 
 lic acid by refrigeration; This acid is more oxy- 
 genated than the oxalic \ and, by a further oxy- 
 genation. 
 
To face Page 267. 
 
 TABLE of the Combinations of Acetous Acid with the Salifiable Bafes in the Order of Affinity. 
 
 j Bafes. 
 
 Neutral falts . 
 
 Names of the rcfulting neutral falts according to the old nomenclature. 
 
 Barytes • 
 
 Acetite of barytes . . 
 
 Unknown to the ancients. Difcovered by Mr de Morveau, who calls it harotic acete. 
 
 j Potaffi .... 
 
 potalh . ' - 
 
 Secret terra foliata tartari of Muller. Arcanum tartari of Bafil Valentin and Paracelfus. 
 Purgative magiftery of tartar of Schroeder. Effential fait of wine of Zwelfer. Regenera- 
 
 L 
 
 foda . . . 
 
 ted tartar of Tachenius. Diuretic fait of Sylvius and Wilfon. 
 
 Foliated earth with bafe of mineral alkali. Mineral or cryftallifable foliated earth. Mineral 
 
 i Lime .... 
 
 lime . . 
 
 acetous fait. 
 
 Salt of chalk, coral, or crabs eyes ; mentioned by Hartman. 
 
 [ Magnefia .. . . 
 
 ■ - ■■ ■ magnefia 
 
 Firft mentioned by Mr Wenzel. 
 
 1 Ammoniac . . . 
 
 — ammoniac 
 
 Spiritus Mindereri. Ammoniacal acetous fait. 
 
 | Oiyd of zinc • 
 
 zinc . . . 
 
 Known to Glauber, Schwedemberg, Refpour, Pott, de LalTone, and Wenzel, but not named. 
 
 manganefe 
 
 manganefe 
 
 iron . . 
 
 Unknown to the ancients. 
 
 Martial vinegar. Defcribed by Monnet, Wenzel, and the Duke d’Ayen. 
 
 lead • . 
 
 lead . . 
 
 Sugar, vinegar, and fait of lead or Saturn. 
 
 tin . . . 
 
 tin . . 
 
 Known to. Lemery, Margraff, Monnet, Weflendorf, and Wenzel, but not named. 
 
 ■ ■■ ■ cobalt . . 
 
 : — cobalt . . 
 
 Sympathetic ink of Mr Cadet. 
 
 ■ ■■ copper . . 
 
 
 Verdigris, cryftals of verditer, verditer, diddled verdigris, cryftals of Venus or of copper. 
 
 ■■■■■ nickel . 
 
 nickel . . 
 
 Unknown to the ancients. 
 
 arfenic . . 
 
 —arfenic . . 
 
 Arfenico-acetous fuming liquor, liquid phofphorus of Mr Cadet. 
 
 bifmuth 
 
 bif uth 
 
 ' Sugar of bifmuth of Mr Geoffroi. Known to Gellert, Pott, Weflendorf, Bergman, and de 
 
 
 mut . . 
 
 Morveau. 
 
 
 
 ’ Mercurial foliated earth, Keyfer’s famous antivenereal remedy. Mentioned by Gebaver in 
 
 mercury 
 
 antimony . 
 
 mercury . 
 
 1748 ; known to Helot, Margraff, Baume, Bergman, and de Morveau. 
 
 antimony 
 
 Unknown. 
 
 ■ fiver . . 
 
 Giver . . 
 
 Defcribed by Margraff, Monnet, and Wenzel ; unknown to the ancients. 
 
 gold . . 
 
 gold . . 
 
 Little known, mentioned by Schroeder and Juncker. 
 
 platina . . 
 
 platina . . 
 
 Unknown. 
 
 Argill .... 
 
 argill . . 
 
 According to Mr Wenzel, vinegar diffolves only a very fmall proportion of argill. 
 
OF CHEMISTRY. a6 7 
 
 genation, the fugar is convertible into acetous 
 acid, or vinegar. 
 
 The oxalic acid, combined with a frnall quan- 
 tity of foda or potalh, has the property, like the 
 tartarous acid, of entering into a number of 
 combinations without fuffering decompofition : 
 Thefe combinations form triple falts, or neutral 
 falts with double bafes, which ought to have 
 proper names. The fait of forrel, which is pot- 
 ato having oxalic acid combined in excefs, is 
 named acidulous oxalat of potalh in our new 
 nomenclature. 
 
 The acid procured from forrel has been 
 known to chemifts for more than a century, 
 being mentioned by Mr Duclos in the Memoirs 
 of the Academy for 1688, and was pretty accu- 
 rately defcribed by Boerhaave \ but Mr Scheele 
 firft toowed that it contained potafh, and de- 
 monftrated its identity with the acid formed by 
 the oxygenation of fugar. 
 
 Sect. XXXIII . — Obfervations upon Acetous Acid , 
 and its Combinations . 
 
 This acid is compofed of charcoal and hy- 
 drogen united together, and brought to the 
 Hate of an acid by the addition of oxygen ; it is 
 confequently formed by the fame elements with 
 
 the 
 
268 ELEMENTS 
 
 the tartarous oxalic, citric, malic acids, and 
 others, but the elements exift in different pro- 
 portions in each of thefe ; and it would appear 
 that the acetous acid is in a higher ftate of oxy- 
 genation than thefe other acids. I have fome 
 reafon to believe that the acetous radical con- 
 tains a fmall portion of azote ; and, as this ele- 
 ment is not contained in the radicals of any ve- 
 getable acid except the tartarous, this circum- 
 ftance is one of the caufes of difference. The 
 acetous acid, or vinegar, is produced by expo- 
 fing wine to a gentle heat, with the addition of 
 fome ferment : This is ufually the ley, or mo- 
 ther, which has feparated from other vinegar 
 during fermentation, or fome fimilar matter. 
 The fpiritous part of the wine, which confifts 
 of charcoal and hydrogen, is oxygenated, and 
 converted into vinegar : This operation can on- 
 ly take place with free accefs of air, and is al- 
 ways attended by a diminution of the air em- 
 ployed in confequence of the abforption of oxy- 
 gen ; wherefore, it ought always to be carried 
 on in veffels only half filled with the vinous li- 
 quor fubmitted to the acetous fermentation. 
 The acid formed during this procefs is very vo- 
 latile, is mixed with a large proportion of wa- 
 ter, and with many foreign fubftances ; and, to 
 obtain it pure, it is diftilled in ftone or glafs 
 veffels by a gentle fire. The acid which paffes 
 over in diftillation is fomewhat changed by the 
 
 procefs, 
 
OF CHEMISTRY. 26 9 
 
 procefs, and is not exactly of the fame nature 
 with what remains in the alembic, but feems 
 lefs oxygenated : This circumdance has not 
 been formerly obferved by chemifts. 
 
 Didillation is not fufficient for depriving this 
 acid of all its urmecedary water ; and, for this 
 purpofe, the bed way is by expofmg it to a de- 
 gree of cold from 4 0 to 6° below the freezing 
 point, from 19 0 to 23 0 of Fahrenheit ; by this 
 means the aqueous part becomes frozen, and 
 leaves the acid in a liquid date, and confidera- 
 bly concentrated. In the ufual temperature of 
 the air, this acid can only exid in the gadeous 
 form, and can only be retained by combination 
 | with a large proportion of water. There are 
 other chemical procedes for obtaining the ace- 
 tous acid, which confid in oxygenating the tar- 
 : tarous, oxalic, or malic acids, by means of nitric 
 icid ; but there is reafon to believe the propor- 
 tions of the elements of the radical are changed 
 luring this procefs. Mr Hadenfratz is at pre- 
 
 1 'ent engaged in repeating the experiments by 
 vhich thefe converdons are faid to be produ- 
 . ;ed. 
 
 The combinations of acetous acid with the 
 r arious falifiable bafes are very readily formed ; 
 >ut mod of the refulting neutral falts are not 
 ridailizable, whereas thofe produced by the 
 1 artarous and oxalic acids are, in general, hard- 
 f foluble. Tartarite and oxalat of lime are 
 
 not 
 
 
ELEMENTS 
 
 rjo 
 
 not foluble in any fenfible degree : The malats 
 are a medium between the oxalats and acetites, 
 with refpeCl to folubility, and the malic acid is 
 in the middle degree of faturation between the 
 oxalic and acetous acids. With this, as with 
 all the acids, the metals require to be oxydated 
 previous to folution. 
 
 The ancient chemifts knew hardly any of the 
 falts formed by the combinations of acetous acid 
 with the falifiable bafes, except the acetites of 
 potafli, foda, ammoniac, copper, and lead. Mr 
 Cadet difcovered the acetite of arfenic # ; Mr 
 Wenzel, the Dijon academicians Mr de Laffone, 
 and Mr Prouft, made us acquainted with the 
 properties of the other acetites. From the pro- 
 perty which acetite of potafli pofleffes, of giving 
 out ammoniac in diftillation, there is fome rea- 
 fon to fuppofe, that, befides charcoal and hy- 
 drogen, the acetous radical contains a fmall 
 proportion of azote, though it is not impoflible 
 but the above production of ammoniac may be 
 occafioned by the decompofition of the potafli. 
 
 Table 
 
 * Savans Etrangers, Vol. III. 
 
OF CHEMISTRY, 
 
 271 
 
 Table of the Combinations of Acetic Acid with 
 the Salifiable Bafes , in the order of affinity . 
 
 Bafes . 
 
 Neutral Salts . 
 
 Barytes 
 
 Acetat of barytes. 
 
 Potafh 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Lime 
 
 lime. 
 
 Magnefia 
 
 magnefia. 
 
 Ammoniac 
 
 ammoniac. 
 
 Oxyd of zinc 
 
 zinc. 
 
 manganefe 
 
 manganefe. 
 
 iron 
 
 iron. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 cobalt 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 nickel 
 
 nickel. 
 
 arfenic 
 
 arfenic. 
 
 bifmuth 
 
 bifmuth. 
 
 mercury 
 
 mercury. 
 
 antimony 
 
 antimony. 
 
 filver 
 
 filver. 
 
 gold 
 
 gold. 
 
 platina 
 
 platina. 
 
 Argill 
 
 argill. 
 
 Sect. 
 
 Note . — All thefe falts were unknown to the ancients; 
 and even thofe chemifts who are moft verfant in mo- 
 dern difcoveries, are yet at a lofe whether the greater 
 part of the falts produced by the oxygenated acetic ra- 
 dical belong properly to the clafs of acetites, or to that 
 of acetats. — A. 
 
Sect. XXXIV . — Obfervations upon Acetic Acid , 
 and its Combinations . 
 
 We have given to radical vinegar the name 
 of acetic acid, from fuppofing that it confifh of 
 the fame radical with that of the acetous acid, 
 but more highly faturated with oxygen. Ac- 
 cording to this idea, acetic acid is the higheft 
 degree of oxygenation of which the hydro-car- 
 bonous radical is fufceptible ; but, although this 
 circumftance be extremely probable, it requires 
 to be confirmed by farther, and more decifive 
 experiments, before it be adopted as an abfo- 
 lute chemical truth. We procure this acid as 
 follows : Upon three parts acetite of potafh or 
 of copper, pour one part of concentrated ful- 
 phuric acid, and, by diflillation, a very highly 
 concentrated vinegar is obtained, which we call 
 acetic acid, formerly named radical vinegar. It 
 is not hitherto rigoroufly proved that this acid 
 ;is more highly oxygenated than the acetous 
 acid, nor that the difference between them may 
 not confifl in a different proportion between the 
 elements of the radical or bafe. 
 
 Table 
 
OF CHEMISTRY. 
 
 2 n 
 
 Table of the Combinations of Succinic Acid with 
 the Salifiable Bafes, in the order of Affinity. 
 
 Bafes . 
 
 Neutral Salts . 
 
 Barytes Succinat of barytes. 
 
 Lime 
 
 lime. 
 
 Potalh 
 
 potafli. 
 
 Soda 
 
 foda. 
 
 Ammoniac 
 
 ammoniac. 
 
 Magnefia 
 
 magnefia. 
 
 Argill 
 
 argill. 
 
 Gxyd of zinc 
 
 zinc. 
 
 iron 
 
 iron. 
 
 manganefe 
 
 manganefe. 
 
 cobalt 
 
 cobalt. 
 
 nickel 
 
 nickel. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 copper 
 
 copper. 
 
 bifmuth 
 
 bifmuth. 
 
 antimony 
 
 antimony; 
 
 arfenic 
 
 arfenic. 
 
 mercury 
 
 mercury. 
 
 filver 
 
 filver. 
 
 gold 
 
 gold. 
 
 platina 
 
 platina. 
 
 Mm Si 
 
 Note . — All the fuccinats were unknown to the 
 cient chemifts. — A. 
 
 J 
 
*74 
 
 ELEMENTS 
 
 Sect. XXXV . — Obfervations upon Succinic Acid y 
 and its Combinations. 
 
 The fuccinic acid is drawn from amber by 
 fublimation in a gentle heat, and rifes in a con- 
 crete form into the neck of the fubliming vef- 
 fel. The operation muft not be pufhed too far, 
 or by too ilrpng a fire, otherwife the oil of the 
 amber rifes aiongfl with the acid. The fait is 
 dried upon blotting paper, and purified by re- 
 peated folution and criitallization. 
 
 T his acid is foluble in twenty-four times its 
 weight of cold water, and in a much fmaller 
 quantity of hot water. It poffeffes the qualities 
 of an acid in a very frnall degree, and only af- 
 fects the blue vegetable colours very {lightly. 
 The affinities of this acid, with the falifiable ba- 
 les, are taken from Mr de Morveau, who is the 
 firft chemift that has endeavoured to afcertain 
 them. 
 
 Sect. 
 
OF CHEMISTRY, 
 
 275 
 
 Sect. XXXVI. — Obfervations upon Benzoic Acid , 
 and its Combinations with Salifiable Bafes *. 
 
 This acid was known to the ancient chemifts 
 under the name of Flowers of Benjamin, or of 
 Benzoin, and was procured, by fublimation, 
 from the gum or refm called Benzoin : The 
 means of procuring it, via humida , was difco- 
 vered by Mr GeofFroy, and perfected by Mr 
 Scheele. Upon benzoin, reduced to powder, 
 pour ftrong lime-water, having rather an excefs 
 of lime \ keep the mixture continually ftirring, 
 and, after half an hour’s digeltion, pour off the 
 liquor, and ufe frefh portions of lime-water in 
 the fame manner, fo long as there is any ap- 
 pearance of neutralization. Join all the de- 
 canted liquors, and evaporate, as far as poiiible, 
 without occafioning criftallization, and, when 
 the liquor is cold, drop in muriatic acid till no 
 more precipitate is formed- By the former par; 
 of the procefs a benzoat of lime is formed, and, 
 by the latter, the muriatic acid combines with 
 the lime, forming muriat of lime, which re- 
 main 5 
 
 * Thefe combinations are called Bejizoats of Lime, 
 Potafh, Zinc, &c. ; but, as the order of affinby is un- 
 known, the alphabetical table is omitted, as uunecef- 
 farv.—E. 
 
276 ELEMENTS 
 
 mains diffolved, while the benzoic acid, being 
 infoluble, precipitates in a concrete ftate. 
 
 Sect. XXXVII. — Obfervations upon Camphoric 
 Acid , and its Combinations with Salifiable 
 Bafes # . 
 
 Camphor is a concrete effential oil, obtained, 
 by fublimation, from a fpecies of laurus which 
 grows in China and Japan. By diddling nitric 
 acid eight times from camphor, Mr Kofegarten 
 converted it into an acid analogous to the oxa- 
 lic ; but, as it differs from that acid in fome 
 circumftances, we have thought neceffary to 
 give it a particular name, till its nature be more 
 completely afcertained by farther experiment. 
 
 As camphor is a carbono- hydrous or hydro- 
 carboilous radical, it is eafily conceived, that, 
 by oxygenation, it fhould form oxalic, malic, 
 and feveral other vegetable acids : This conjec- 
 ture is rendered not improbable by the experi- 
 ments of Mr Kofegarten ; and the principal 
 phenomena exhibited in the combinations of 
 camphoric acid with the falifiable bafes, being 
 
 very 
 
 % Tliefe combinations, which were all unknown 1(3 
 the ancients, are called Camphorats. The table is 
 omitted, as bein^ onlj in alphabetical order. — E. 
 
OF CHEMISTRY. 
 
 '*71 
 
 very fimilar to thofe of the oxalic and malic 
 acids, lead me to believe that it confifts of a 
 mixture of thefe two acids. 
 
 Sect. XXXVIII . — Obfervations upon Gallic Acid 9 
 and its Combinations with Salifiable Bafes 
 
 The Gallic acid, formerly called Principle of 
 Afhingency, is obtained from gall nuts, either 
 by infufion or decoftion with water, or by di- 
 flillation with a very gentle heat. This acid 
 has only been attended to within thefe few years. 
 The Committee of the Dijon Academy have 
 followed it through all its combinations, and 
 give the bed account of it hitherto produced. 
 Its acid properties are very weak ; it reddens 
 the tin&ure of turnfol, decompofes fulphurets, 
 and unites to all the metals when they have 
 been previoufly diffolved in fome other acid. 
 Iron, by this combination, is precipitated of a 
 very deep blue or violet colour. The radical 
 of this acid, if it deferves the name of one, is 
 hitherto entirely unknown ; it is contained in 
 
 oak 
 
 * Thefe combinations, which are called Gallats, 
 were all unknown to the ancients ; and the- order of 
 their affinity is not hitherto eftabliffied. — -A. 
 
fe 7 8 ELEMENTS 
 
 oak willow, marfh iris, the ftrawberry, nyra- 
 phea, Peruvian bark, the flowers and bark of 
 pomgranate, and in many other woods and 
 barks. 
 
 Sect. XXXI X.—Obfervations upon Laftic Acid , 
 and its Combinations with Salifiable Bafes *. 
 
 The only accurate knowledge we have of this 
 acid is from the works of Mr Scheele. It is 
 contained in whey, united to a fmall quantity 
 of earth, and is obtained as follows : Reduce 
 whey to one eighth part of its bulk by evapo- 
 ration, and filtrate, to feparate all its cheefy 
 matter ; then add as much lime as is neceffary 
 to combine with the acid; the lime is afterwards 
 difengaged by the addition of oxalic acid, which 
 combines with it into an infolubie neutral fait. 
 When the oxalat of lime has been feparated by 
 decantation, evaporate the remaining liquor to 
 the confiftence of honey ; the la&ic acid is dif- 
 folved by alkohol, which does not unite with 
 the fugar of milk and other foreign matters ; 
 
 thefe 
 
 * Thefe combinations are called Ladlats ; they were 
 all unknown to the ancient chemifts, and their affini- 
 ties have not yet been afcertained. — A. 
 
OF CHEMISTRY. 
 
 m 
 
 thefe are feparated by filtration from the alko 
 hoi and acid; and the alkohol being evaporated, 
 or diftilled off, leaves the la&ic acid behind. 
 
 This acid unites with all the falifiable bafes 
 forming falts which do not criftallize ; and it 
 feems confiderably to refemble the acetous acid. 
 
 Tabl$ 
 
*8o ELEMENTS 
 
 Table of the Combinations of Saccholaftic Acid 
 with the Salifiable Bafes , in the Order of 
 Affinity . 
 
 Bafes, 
 
 Neutral Salts . 
 
 Lime Saccholat of lime. 
 
 Barytes 
 
 barytes. 
 
 Magnefia 
 
 magnefia. 
 
 Potafli 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Ammoniac 
 
 ammoniac. 
 
 Argill 
 
 argill. 
 
 Oxyd of zinc 
 
 zinc. 
 
 manganefe 
 
 manganefe. 
 
 iron 
 
 iron. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 cobalt ' 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 nickel 
 
 nickel. 
 
 arfenic 
 
 arfenic. 
 
 bifmuth 
 
 bifmuth. 
 
 mercury 
 
 mercury. 
 
 antimony 
 
 antimony. 
 
 filver 
 
 filver. 
 
 Sect* 
 
 Note *~ All thefe were unknown to the ancient che« 
 mi ft s.— A. 
 
OF CHEMISTRY, 
 
 28: 
 
 Sect. XL . — Obfervations upon Saccholadic Acid , 
 and its Combinations • 
 
 A fpecies of fygar may be extracted, by eva- 
 poration, from whey, which has long been 
 known in pharmacy, and which has a confide- 
 rable refemblance to that procured from fugar 
 canes. This faccharine matter, like ordinary 
 fugar, may be oxygenated by means of nitric 
 acid : For this purpofe, feveral portions of ni- 
 tric acid are diflilled from it ; the remaining li- 
 quid is evaporated, and fet to criftallize, by 
 which means criftals of oxalic acid are procu- 
 red 5 at the fame time a very fine white powder 
 precipitates, which is the facchola&ic acid dif- 
 covered by Scheele. It is fufceptible of com- 
 bining with the alkalies, ammoniac, the earths, 
 and even with the metals: Its a&ion upon the 
 latter is hitherto but little known, except that, 
 with them, it forms difficultly foluble falts. The 
 order of affinity in the table is taken from Berg- 
 man. 
 
 N n 
 
 Table 
 
$82 
 
 ELEMENTS 
 
 Table of the Combinations of Formic Acid , with 
 the Salifiable Bafes 9 in the Order of Affinity . 
 
 Bafes. 
 
 Neutral Salts . 
 
 Barytes 
 
 Formiat of barytes* 
 
 Potafh 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Lime 
 
 lime. 
 
 Magnefia 
 
 magnefia. 
 
 Ammoniac 
 
 ammoniac* 
 
 Oxyd of 
 
 
 zinc 
 
 zinc. 
 
 manganefe 
 
 manganfcfe. 
 
 iron 
 
 iron. 
 
 lead 
 
 lead. 
 
 tin 
 
 tin. 
 
 cobalt 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 nickel 
 
 nickel. 
 
 bifmuth 
 
 bifmuth. 
 
 filver 
 
 filver. 
 
 Argill 
 
 argill. 
 
 Sect* 
 
 Note . — All unknown to the ancient chemifls. — A. 
 
 t 
 
OF CHEMISTRY. 283 
 
 Sect. XLI . — Obfervations upon Formic Acid , and 
 its Combinations . 
 
 This acid was firfl obtained by diftillation 
 from ants, in the laft century, by Samuel Fifh- 
 er. The fubjed was treated of by Margraff in 
 1749, and by Mefirs Ardwiffon and Ochrn of 
 Leipfic in 1777. The formic acid is drawn 
 from a large fpecies of red ants, fonnica rufa y 
 Lin . which form large ant hills in woody places. 
 It is procured, either by diftilling the ants with 
 a gentle heat in a glafs retort or an alembic ; 
 or, after having walhed the ants in cold water, 
 and dried them upon a cloth, by pouring on 
 boiling water, which diffolves the acid ; or the 
 acid may be procured by gentle expreflion from 
 the infeds, in which cafe it is ftronger than in 
 any of the former ways. To obtain it pure, we 
 muft redify, by means of diftillation, which fe« 
 parates it from the uncombined oily and charry 
 matter ; and it may be concentrated by freezing, 
 in the manner recommended for treating the 
 acetous acid. 
 
 Sect* 
 
Sect. XLII . — Obfervations upon Bombic Add , 
 arid its Combinations with Addiftable Bafes *. 
 
 The juices of the filk worm feem to affume 
 an acid quality when that infe£t changes from 
 a larva to a chryfalis. At the moment of its 
 efcape from the latter to the butterfly form, it 
 emits a reddifli liquor which reddens blue pa- 
 per, and which was firfl: attentively obferved by 
 Mr Chauflier of th.e Dijon academy, who ob- 
 tains the acid by infufmg filk worm chryfalids 
 in alkohol, which diffolves their acid without 
 being charged with any of the gummy parts of 
 the infeft ; and, by evaporating the alkohol, the 
 acid remains tollerably pure. The properties 
 and affinities of this acid are not hitherto ascer- 
 tained with any precifion ; and we have reafon 
 to believe that analogous acids may be procu- 
 red from other infedls. The radical of this acid 
 is probably, like that of the other acids from 
 the animal kingdom, compofed of charcoal, hy- 
 drogen, and azote, with the addition, perhaps, 
 of phofphorus. 
 
 Table 
 
 * Thefe combinations named Bombats were un- 
 known to the ancient chemifts ; and the affinities of 
 the falifiable bafes with the bombic acid are hitherto 
 undetermined. — A. 
 
OF CHEMISTRY, 
 
 285 
 
 Table of the Combinations of the Sebacic Acid y 
 with the Salifiable Bafes> in the Order of Affi- 
 nity, 
 
 Bafes . 
 
 Neutral Salts . 
 
 Barytes 
 
 Sebat of barytes. 
 
 Potafh 
 
 potafh. 
 
 Soda 
 
 foda. 
 
 Lime 
 
 lime. 
 
 Magnefia 
 
 magnefia. 
 
 Ammoniac 
 
 ammoniac. 
 
 Argill 
 
 argill. 
 
 Oxyd of 
 
 
 zinc 
 
 zinc. 
 
 manganefe 
 
 manganefe. 
 
 iron 
 
 iron. 
 
 lead 
 
 lead 
 
 tin 
 
 tin. 
 
 cobalt 
 
 cobalt. 
 
 copper 
 
 copper. 
 
 nickel 
 
 nickel. 
 
 arfenic 
 
 arfenic. 
 
 bifmuth 
 
 bifmuth. 
 
 mercury 
 
 * mercury. 
 
 antimony 
 
 antimony. 
 
 filver 
 
 filver. 
 
 Sect, 
 
 Note . — All thefe were unknown to the ancient c he- 
 mills. — A, 
 
*86 
 
 ELEMENTS 
 
 Sect. XLI1I . — Obfervations upon Sebacid Acid , 
 and its Combinations . 
 
 To obtain the febacic acid, let fome fuet be 
 melted in a fkillet over the fire, alongft with 
 fome quick-lime in fine powder, and conflantly 
 ftirred, raifing the fire towards the end of the 
 operation, and taking care to avoid the vapours, 
 which are very offenfive. By this procefs the 
 febacic acid unites with the lime into a febat of 
 lime, which is difficultly foluble in water ; it is, 
 however, feparated from the fatty matters with 
 which it is mixed by folution in a large quan- 
 tity of boiling water. From this the neutral fait 
 is feparated by evaporation ; and, to render it 
 pure, is calcined, rediffoived, and again criftal- 
 lized. After this we pour on a proper quantity 
 of fulphuric acid, and the febacic acid paffes 
 over by diftillation. 
 
 Sect. 
 
OF CHEMISTRY. 287 
 
 Sect. XLIV. — Obfervations upon the Lithic Acid* 
 
 and its Combinations with the Salifiable Bafes ** 
 
 From the later experiments of Bergman and 
 Scheele, the urinary calculus appears to be a 
 fpecies of fait with an earthy bafis ; it is llightly 
 acidulous, and requires a large quantity of wa- 
 ter for folution, three grains being fcarcely fo- 
 luble in a thoufand grains of boiling water, and 
 the greater part again criftallizes when cold. 
 To this concrete acid, which Mr de Morveau 
 calls Lithiafic Acid, we give the name of Lithic 
 Acid, the nature and properties of which are 
 hitherto very little known. There is fome ap- 
 pearance that it is an acidulous neutral fait, or 
 acid combined in excefs with a falifiable bafe ; 
 and I have reafon to believe that it really is an 
 acidulous phofphat of lime ; if fo, it mull be 
 excluded from the clafs of peculiar acids. 
 
 Table 
 
 * Ail the combinations of this acid, fhould it final- 
 ly turn out to be one, were unknown to the ancient 
 chemifts, and its affinities with the falifiable bafes have 
 not been hitherto determined. — A. 
 
2*8 
 
 ELEMENTS 
 
 Table of the Combinations of the P ruffic Acid 
 with the Salifiable Bafes , in the order of affinity • 
 
 Bafes. 
 
 Potafh 
 
 Soda 
 
 Ammoniac 
 Lime 
 Barytes 
 Magnefia 
 Oxyd of zinc 
 iron 
 
 manganefe 
 
 cobalt 
 
 nickel 
 
 lead 
 
 * tin 
 
 copper 
 
 bifmuth 
 
 antimony 
 
 arfenic 
 
 filver 
 
 mercury 
 
 gold 
 
 platina 
 
 Neutral Salts . 
 Prufliat of potafh, 
 foda. 
 
 ammoniac, 
 
 lime. 
 
 barytes. 
 
 magnefia. 
 
 zinc. 
 
 iron. 
 
 manganefe. 
 
 cobalt. 
 
 nickel. 
 
 lead. 
 
 tin. 
 
 copper. 
 
 bifmuth. 
 
 antimony. 
 
 arfenic. 
 
 filver. 
 
 mercury. 
 
 gold. 
 
 platina. 
 
 Obfer - 
 
 Note. All thefe were unknown to former che- 
 
 mifts.—A. 
 
OF CHEMISTRY. 
 
 ,289 
 
 Obfervations upon the PruJJic Acid , and its Com- 
 binations, 
 
 As the experiments which have been made 
 hitherto upon this acid feem ftill to leave aconfi- 
 derable degree of uncertainty with regard to its 
 nature, I fliall not enlarge upon its properties, 
 and the means of procuring it pure and diffen- 
 gaged from combination. It combines with 
 iron, to which it communicates a blue colour, 
 and is equally fufceptible of entering into com- 
 bination with moil of the other metals, which 
 are precipitated from it by the alkalies, ammo- 
 niac, and lime, in confequence of greater affi- 
 nity. The Pruffic radical, from the experiments 
 of Scheele, and efpeciaiiy from thofe of Mr Ber- 
 thollet, feems compofed of charcoal and azote ; 
 hence it is an acid with a double bafe. The 
 phofphorus which has been found combined 
 with it appears, from the experiments of Mr 
 Haifenfratz, to be only accidental. 
 
 Although this acid combines with alkalies, 
 earths, and metals, in the fame way with other 
 acids, it poifeffes only fome of the properties we 
 have been in ufe to attribute to acids, and it 
 may consequently be improperly ranked here in 
 O o th^ 
 

 g 9 o ELEMENTS 
 
 the clafs of acids ; but, as I have already ob- 
 ferved, it is difficult to form a decided opinion 
 upon the nature of this fubftance until the fub- 
 je& has been farther elucidated by a greater 
 number of experiments. 
 
 PART 
 
 
OF CHEMISTRY. 
 
 291 
 
 PART III. 
 
 Defcription of the Inftruments and 
 Operations of Chemiftry. 
 
 INTRODUCTION. 
 
 I 
 
 I N the two former parts of this work I defign- 
 edly avoided being particular in defcribing 
 the manual operations of chemiftry, becaufe I 
 had found from experience, that, in a work ap- 
 propriated to reafoning, minute defcriptions of 
 procefles and of plates interrupt the chain of 
 ideas, and render the attention neceffary both 
 difficult and tedious to the reader. On the 
 other hand, if I had confined myfelf to the fum- 
 
 I mary defcriptions hitherto given, beginners 
 could have only acquired very vague concep- 
 tions of practical chemiftry from my work, and 
 muft have wanted both confidence and intereft 
 in operations they could neither repeat nor 
 
 thoroughly 
 
ELEMENTS 
 
 292 
 
 thoroughly comprehend. This want could not 
 have been fupplied from books ; for, befides 
 that there are not any which defcribe the mo- 
 dern inflruments and experiments fufficiently at 
 large, any work that could have been confulted 
 would have prefented thefe things under a very 
 different order of arrangement, and in a dif- 
 ferent chemical ianguage, which muff greatly 
 tend to injure the main objedt of my perform- 
 ance. 
 
 Influenced by thefe motives, I determined to 
 referve, for a third part of my work, a fummary 
 defcription of all the inflruments and manipula- 
 tions relative to elementary chemiftry. I con- 
 fidered. it as better placed at the end, rather 
 than at the beginning of the book, becaufe I 
 muft have been obliged to fuppofe the reader 
 acquainted with circumftances which a begin- 
 ner cannot know 7 , and muft therefore have read 
 the elementary part to become acquainted with. 
 The whole of this third part may therefore be 
 confidered as refembling the explanations of 
 plates which are ufually placed at the end of 
 academic memoirs, that they may not interrupt 
 the connection of the text by lengthened de- 
 fcription. Though I have taken great pains to 
 render this part clear and methodical, and have 
 not omitted any eflential inftrument or appara- 
 tus, I am far from pretending by it to fet afide 
 the neceflity of attendance upon lectures and la- 
 boratories. 
 
OF CHEMISTRY. 
 
 boratories, for fuch as wilh to acquire accurate 
 knowledge of the fcience of chemiftry. Thefe 
 fhould familiarife themfelves to the employment 
 of apparatus, and to the performance of experi- 
 ments by a&ual experience. Nihil eft in intel - 
 ieftu quod non prius fuerit in fenfu , the motto 
 which the celebrated Rouelie caufed to be pain- 
 ted in large characters in a confpicuous part of 
 his laboratory, is an important truth never to 
 be loft fight of either by teachers or ftudents of 
 chemiftry. 
 
 Chemical operations may be naturally divided 
 into feveral claffes, according to the purpofes 
 they are intended for performing. Some may 
 be confidered as purely mechanical, fuch as the 
 determination of the weight and bulk of bodies, 
 trituration, levigation, fearching, wafhing, fil- 
 tration, &c. Others may be confidered as real 
 chemical operations, becaufe they are perform- 
 ed by means of chemical powers and agents ; 
 fuch are folution, fufion, &c. Some of thefe 
 are intended for feparating the elements of bo- 
 dies from each other, fome for reuniting thefe 
 elements together ; and fome, as combuftion, 
 produce both thefe effects during the fame pro- 
 cefs. 
 
 Without rigoroufiy endeavouring to follow 
 the above method, I mean to give a detail of 
 the chemical operations in fuch order of ar- 
 rangement as feemed beft calculated for con- 
 veying 
 
294 
 
 ELEMENTS 
 
 veying inftru&ion. I fhall be more particular 
 in defcribing the apparatus conne&ed with mo- 
 dern chemiftry, becaufe thefe are hitherto little 
 known by men who have devoted much of their 
 time to chemiftry, and even by many profeffors 
 of the fcience. 
 
 CHAR 
 
OF CHEMISTRY. 
 
 2 95 
 
 CHAP. I. 
 
 Of the Injlruments necejfary for determining the 
 Ahfolute and Specific Gravities of Solid and Li- 
 quid Bodies. 
 
 T HE beft method hitherto known for deter- 
 mining the quantities of fubftances fub- 
 mitted to chemical experiment, or refulting from 
 them, is by means of an accurately conftrufted 
 beam and fcales, with properly regulated weights, 
 which well known operation is called weighing. 
 The denomination and quantity of the weights 
 ufed as an unit or ftandard for this purpofe are 
 extremely arbitrary, and vary not only in diffe- 
 rent kingdoms, but even in different provinces 
 of the fame kingdom, and in different cities of 
 the fame province. This variation is of infinite 
 confequence to be well underflood in commerce 
 and in the arts \ but, in chemiftry, it is of no 
 moment what particular denomination of weight 
 be employed, provided the refults of experi- 
 ments be expreffed in convenient fra&ions of 
 the fame denomination. For this purpofe, un- 
 til all the weights ufed in fociety be reduced to 
 the fame ftandard, it will be fufficient for che- 
 mifts in different parts to ufe the common 
 
 pound 
 
ELEMENTS 
 
 296 
 
 pound of their own country as the unit or 
 ftandard, and to exprefs all its fractional parts 
 in decimals, inftead of the arbitrary divifions 
 now in ufe. By this means the chemifts of all 
 countries will be thoroughly underftood by each 
 other, as, although the abfolute weights of the 
 ingredients and products cannot be known, they 
 will readily, and without calculation, be able to 
 determine the relative proportions of thefe to 
 each other with the utmoft accuracy ; fo that in 
 this way we fhall be poffeffed of an univerfal 
 language for this part of chemiftry. 
 
 With this view I have long projected to have 
 the pound divided into decimal fractions, and I 
 have of late fucceeded through the afliftance of 
 Mr Fourche balance-maker at Paris, who has 
 executed it for me with great accuracy and 
 judgment. I recommend to all who carry on 
 experiments to procure fimilar divifions of the 
 pound, which they will find both eafy and fim- 
 ple in its application, with a very fmall know- 
 ledge of decimal fractions *• 
 
 As 
 
 * Mr Lavoifier gives, in this part of his work, very 
 accurate direftions for reducing the common fubdivi- 
 fions of the French pound into decimal fractions, and 
 vice verfa , by means of tables fubjoined to this sd part. 
 As thefe inftru&ions, and the table, would be ufelefs to 
 the Britifh chemift, from the difference between the 
 fubdivifions of the French and Troy pounds, I have 
 omitted them, but have fubjoined in the appendix ac- 
 curate rules for converting the one iiito the other. — E, 
 
OF CHEMISTRY. 297 
 
 As the ufefulnefs and accuracy of chemiftry 
 depends entirely upon the determination of the 
 weights of the ingredients and produ&s both 
 before and after experiments, too much preci- 
 fion cannot be employed in this part of the fub- 
 je& ; and, for this purpofe, we muft be provided 
 with good inftruments. As we are often obli- 
 ged, in chemical proceffes, to afcertain, within 
 a grain or lefs, the tare or weight of large and 
 heavy inftruments, we muft have beams made 
 with peculiar nicenefs by accurate workmen, 
 and thefe muft always be kept apart from the 
 laboratory in fome place where the vapours of 
 acids, or other corrofive liquors, cannot have 
 accefs, otherwife the fteel will ruft, and the ac- 
 curacy of the balance be deftroyed. 1 have 
 three fets, of different fizes, made by Mr Fon- 
 tin with the utmoft nicety, and, excepting thofe 
 made by Mr Ramfden of London, I do not 
 think any can compare with them for precifion 
 and fenfibility. The largeft of thefe is about 
 three feet long in the beam for large weights, 
 up to fifteen or twenty pounds ; the fecond, for 
 weights of eighteen or twenty ounces, is exa & 
 to a tenth part of a grain ; ‘and the finalfeft, 
 calculated only for weighing about one gros, is 
 fenfibly affe&ed by the five hundredth part of a 
 grain. 
 
 Befides thefe nicer balances, which are only 
 ufed for experiments of refearch, we muft have 
 P p others 
 
ELEMENTS 
 
 s 9 3 
 
 others of lefs value for the ordinary purpofes of 
 the laboratory. A large iron balance, capable 
 of weighing forty or fifty pounds within half a 
 dram, one of a middle fize, which may afcer- 
 tain eight or ten pounds, within ten or twelve 
 grains, and a fmall one, by which about a 
 pound may be determined, within one grain. 
 
 We mud likewife be provided with weights 
 divided into their feveral fra£tion$, both vulgar 
 and decimal, with the utmoft nicety, and veri- 
 fied by means of repeated and accurate trials in 
 the niceft fcales ; and it requires fome experi- 
 ence, and to be accurately acquainted with the 
 different weights, to be able to ule them pro- 
 perly. The beff way of precifely afcertaining 
 the weight of any particular fubftance is to 
 weigh it twice, once with the decimal divifions 
 of the pound, and another time with the com- 
 mon fubdivifions or vulgar fraftions, and, by 
 comparing thefe, we attain the utmoft accuracy. 
 
 By the fpecific gravity of any fubftance is 
 underftood the quotient of its abfolute weight 
 divided by its magnitude, or, what is the fame, 
 the weight of a determinate bulk of any body. 
 The weight of a determinate magnitude of wa- 
 ter has been generally afi'umed as unity for this 
 purpofe ; and we exprefs the fpecific gravity of 
 gold, fulphuric acid, &c. by faying, that gold is 
 nineteen times, and fulphuric acid twice the 
 weight of water, and fo of other bodies. 
 
 It 
 
OF CHEMISTRY. 299 
 
 It is the more convenient to affurae water as 
 unity in fpecific gravities, that thofe fubftances 
 whofe fpecific gravity we wifh to determine, are 
 moft commonly weighed in water for that pur- 
 pofe. Thus, if we wifh to determine the fpe- 
 cific gravity of gold flattened under the ham- 
 mer, and fuppofing the piece of gold to weigh 
 8 oz. 4 gros 2~ grs. in the air *, it is fufpended 
 by means of a fine metallic wire under the fcale 
 of a hydroftatic balance, fo as to be entirely 
 immerfed in water, and again weighed, The 
 piece of gold in Mr Briffon’s experiment loft 
 by this means 3 gros 37 grs . - 9 and, as it is evi- 
 dent that the weight loft by a body weighed in 
 water is precifely equal to the weight of the 
 water difplaced, or to that of an equal volume 
 of water, we may conclude, that, in equal mag- 
 nitudes, gold weighs 4893-^ grs . and water 253 
 grs . which, reduced to unity, gives 1,0000 as 
 the fpecific gravity of water, and 19.3617 for 
 that of gold. We may operate in the fame 
 manner with all folid fubftances. We have 
 rarely any occafion, in chemiftry, to determine 
 the fpecific gravity of folid bodies, unlefs when 
 operating upon alloys or metallic giafles ; but 
 We have very frequent neceflity to ascertain that 
 of fluids, as it is often the only means of judg- 
 ing of their purity or degree of concentration* 
 
 This 
 
 * Vide Mr Bri/Ton's Effay upqn Specific Gravity, 
 
 p. 5— A. 
 
ELEMENTS 
 
 30a 
 
 This object may be very fully accompliftred 
 with the hydroftatic balance, by weighing a fo- 
 lid body ; fuch, for example, as a little ball of 
 rock criftal fufpended by a very fine gold wire, 
 firft in the air, and afterwards in the fluid 
 whofe fpecific gravity we wifh to difcover. The 
 weight loft by the criftal, when weighed in the 
 liquor, is equal to that of an equal bulk of the 
 liquid. By repeating this operation fucceflively 
 in water and different fluids, we can very readi- 
 ly afcertain, by a fimple and eafy calculation, 
 the relative fpecific gravities of thefe fluids, 
 either with refpedt to each other or to water. 
 This method is not, however, fufficiently exaft, 
 or, at leaft, is rather troublefome, from its ex- 
 treme delicacy, when ufed for liquids differing 
 but little in fpecific gravity from water ; fuch, 
 for inftance, as mineral waters, or any other 
 water containing very fmall portions of fait in 
 folution. 
 
 In fome operations of this nature, which 
 have not hitherto been made public, I employed 
 an inftrument of great fenfibility for this pur- 
 pose with great advantage. It confifts of a hol- 
 low cylinder, Abcf , PI. vii. fig. 6. of brafs, 
 or rather of filver, loaded at its bottom, be f, with 
 tin, as reprefented fwimming in a jug of water, 
 Jmno. To the upper part of the cylinder is 
 attached a ftalk of filver wire, not more than 
 three fourths of a line diameter, furmounted by 
 
 a 
 
OF CHEMISTRY. 30 1\ 
 
 a little cup d, intended for containing weights ; 
 upon the {talk a mark is made at g, the ufe of 
 which we fhall prefently explain. This cylin- 
 der may be made of any fize ; but, to be accu- 
 rate, ought at lead to difplace four pounds of 
 water. The weight of tin with which this in- 
 ftrument is loaded ought to be fuch as will make 
 it remain almod in equilibrium in diltilled wa- 
 ter, and fhould not require more than half a 
 dram, or a dram at molt, to make it fink to g. 
 
 We mud fird determine, with great preci- 
 fion, the exaft weight of the indrument, and 
 the number of additional grains requifite for 
 making it fink, in didilled water of a determi- 
 nate temperature, to the mark : We then per- 
 form the fame experiment upon all the fluids 
 of which we wifh to afcertain the fpecific gravi- 
 ty, and, by means of calculation, reduce the 
 obferved differences to a common ftandard of 
 cubic feet, pints or pounds, or of decimal frac- 
 tions, comparing them with water. This me- 
 thod, joined to experiments with certain rea- 
 gents *, is one of the bed for determining the 
 quality of waters, and is even capable of point- 
 ing out differences which efcape the mod accu- 
 rate chemical analyfis. I fhall, at fome future 
 
 period, 
 
 * For the ufe of thefe reagents fee Bergman's excel- 
 lent treatife upon the analyfis of mineral waters, in his 
 Chemical and Phyfical EiTays.— E. 
 
3«3 ELEMENT S 
 
 ' 
 
 period, give an account of a very extenfive fet 
 of experiments which I have made upon this 
 fubjeft. 
 
 Thefe metallic hydrometers are only to be 
 ufed for determining the fpecific gravities of 
 fuch waters as contain only neutral falts or al- 
 kaline fubdances ; and they may be condru&ed 
 with different degrees of ballad for alkohol and 
 other fpiritous liquors. When the fpecific gra- 
 vities of acid liquors are to be afcertained, we 
 mud ufe a glafs hydrometer, as represented 
 PL vii. fig. 14 f. This confids of a hollow cy- 
 linder of glafs, abcf 9 hermetically fealed at its 
 lower end, and drawn out at the upper into a 
 capillary tube a , ending in the little cup or ba- 
 ton d. This indrument is balladed with more 
 or lets mercury, at the bottom of the cylinder 
 introduced through the tube, in proportion to 
 the weight of the liquor intended to be examin- 
 ed : We may introduce a fmall graduated flip 
 of paper into the tube ad; and, though thefe 
 degrees do not exa&ly correfpond to the frac- 
 tions of grains in the different liquors, they may 
 be rendered very ufeful in calculation. 
 
 What is faid in this chapter may fuffice, 
 without farther enlargement, for indicating the 
 
 means 
 
 + Three or four years ago, I have feen fimilar gla (2 
 hydrometers, made for Dr Black by B. Knie, a very 
 ingenious artift of this city.— E* 
 
OF CHEMISTRY. 
 
 Z% 
 
 means of afcertaining the abfolute and fpecific 
 gravities of foiids and fluids, as the neceffary 
 inftruments are generally known, and may eafl- 
 ly be procured : But, as the inflruments I have 
 ufed for meafuring the gaffes are not any where 
 defcribed, I (hall give a more detailed account 
 of thefe in the following chapter. 
 
ELEMENTS 
 
 CHAP. II. 
 
 Of Gazometry, or the Meafurement of the Weight 
 and Volume of Aeriform Sub/lances. 
 
 0 
 
 SECT. I. 
 
 'Pefcription of the Pneumato chemical Apparatus . 
 H E French chemifts have of late applied 
 
 the name of pneumato chemical apparatus 
 to the very fimple and ingenious contrivance, 
 invented by Dr Prieftley, which is now indifpen- 
 fibiy neceftary to every laboratory. This con- 
 fifts of a wooden trough, of larger or fmaller 
 dimenfions as is thought convenient, lined with 
 plate-lead or tinned copper, as reprefented in 
 perfpe&ive, PI. V. In Fig. 1. the fame trough or 
 ciftern is fuppofed to have two of its Tides cut a- 
 way, to fhow r its interior conftru&ion more di- 
 ftinctly. In this apparatus, we diftinguifh be- 
 tween the flielf ABCD Fig. i. and 2. and the 
 bottom or body of the ciftern FGHI Fig. 2. 
 
 The 
 
OF CHEMISTRY. 
 
 305 
 
 The jars or bell-glaffes are filled with water 
 in this deep part, and, being turned with their 
 mouths downwards, are afterwards fet upon the 
 fhelf ABCD, as fhown Plate X. Fig. 1 . F, The 
 upper parts of the fides of the cittern above the 
 level of the fhelf are called the rim or borders . 
 
 The cittern ought to be filled with water, fo 
 as to ttand at leaft an inch and a half deep up- 
 on the fhelf, and it fhould be of fuch dimen- 
 fions as to admit of at leatt one foot of water in 
 every dire&ion in the well. This fize is fuffi- 
 cient for ordinary occafions ; but it is often 
 convenient, and even neceflary, to have more 
 room ; I would therefore advife fuch as intend 
 to employ themfelves ufefully in chemical expe- 
 riments, to have this apparatus made of confii- 
 derable magnitude, w'here th.eir place of opera- 
 ting will allow. The well of my principal cittern 
 holds four cubical feet of water, and its fhelf 
 has a furface of fourteen fquare feet ; yet, in 
 fpite of this fize, which I at firft thought im- 
 moderate, I am often ftraitened for room. 
 
 In laboratories, where a confiderable number 
 of experiments are performed, it is neceflary to 
 have feveral letter citterns, befides the large one, 
 which may be called the general magazine ; and 
 even fome portable ones, which may be moved 
 when neceflary, near a furnace, or wherever 
 they may be wanted. There are likewife fome 
 operations which dirty the water of the appara- 
 O^q tus. 
 
3 o6 ELEMENTS 
 
 tus, and therefore require to be carried on in 
 ciflerns by themfelves. 
 
 It were doubtlefs confiderably cheaper to ufe 
 ciderns, or iron-bound tubs, of wood fimply 
 dove-tailed, infhead of being lined with lead or 
 copper ; and in my firft experiments I ufed 
 them made in that way ; but I foon difcovered 
 their inconvenience. If the water be not always 
 kept at the fame level, fuch of the dovetails as 
 are left dry fhririk, and, when more water is 
 added, it efcapes through the joints, and runs 
 out. 
 
 We employ criftal jars or bell glaffes, PI. V. 
 Fig. 9. A. for containing the gaffes in this ap- 
 paratus ; and, for tranfporting thefe, when full 
 of gas, from one ciftern to another, or for keep- 
 ing them in referve when the ciftern is too full, 
 we make ufe of a flat difh BC, furrounded by a 
 {landing up rim or border, with two handles 
 DE for carrying it by. 
 
 After feveral trials of different materials, I 
 have found marble the beft fubftance for con- 
 ftrufting the mercurial pneumato-chemical ap- 
 paratus, as it is perfectly impenetrable by mer- 
 cury, and is not liable like wood, to feparate at 
 the jun&ures, or to allow the mercury to efcape 
 through chinks ; neither does it run the rifk of 
 breaking, like glafs, ftone-ware, or porcelain. 
 Take a block of marble BCDE, Plate V. Fig. 3. 
 and 4. about two feet long, 15 or 18 inches 
 
 broad, 
 
OF CHEMISTRY. 
 
 3°7 
 
 broad, and ten inches thick, and caufe it to be 
 hollowed out as at m n Fig. 5. about four inches 
 deep, as a refer voir for the mercury ; and, to 
 be able more conveniently to fill the jars, cut 
 the gutter T V, Fig. 3. 4. and 5. at lead four 
 inches deeper ; and, as this trench may fome- 
 times prove troublefome, it is made capable of 
 being covered at pleafure by thin boards, which 
 flip into the grooves x y , Fig. 5. I have two 
 marble citterns upon this conftru&ion, of dif- 
 ferent fizes, by which I can always employ one 
 of them as a refervoir of mercury, which it pre- 
 ferves with more fafety than any other veffel, being 
 neither fubjed to overturn, nor to any other 
 accident. We operate with mercury in this ap- 
 paratus exactly as with water in the one before 
 defcribed ; but the bell-glaffes muft be of fmaller 
 diameter, and much ttronger ; or we may ufe glafs 
 tubes, having their mouths widened, as in Fig. 
 7. ; thefe are called eudiometers by the glafs^men 
 who fell them. One of the bell glafies is repre- 
 fented Fig. 5. A. (landing in its place, and what 
 is called ajar is engraved Fig, 6. 
 
 The mercurial pneumato-chemical apparatus 
 is necefiary in all experiments wherein the un- 
 engaged gattes are capable of being abforbed by 
 water, as is frequently the cafe, efpecially in all 
 combinations, excepting thofe of metals, in fer* 
 mentation, &c. 
 
 SEC T. 
 
ELEMENTS 
 
 308 
 
 SECT. II. 
 
 Of the G azometer. 
 
 I give the name of gazometer to an inftrument 
 which I invented, and caufed conftruft, for the 
 purpofe of a kind of bellows, which might fur- 
 nifh an uniform and continued ftream of oxy- 
 gen gas in experiments of fufion. Mr Meuf* 
 nier and I have fince made very confiderable 
 correftions and additions, having converted it 
 into what may be called an univerfal inftrument , 
 without which it is hardly poffible to perform 
 mod of the very exact experiments. The name 
 we have given the inftrument indicates its in- 
 tention for meafuring the volume or quantity of 
 gas fubmitted to it for examination. 
 
 It confifts of a ftrong iron beam, DE, PI. VIII. 
 Fig. 1. three feet long, having at each end, D 
 and'E, a fegment of a circle, likewife ftrongly 
 conftru&ed of iron, and very firmly joined. In- 
 ftead of being poifed as in ordinary balances, 
 this beam refts, by means of a cylindrical axis 
 of polifhed fteel, F, Fig. 9. upon two large 
 ' moveable brafs fri&ion-wheels, by which the re- 
 fiftance to its motion from fri&ion is confider- 
 ably diminifhed, being converted into fri&ion 
 
 of 
 
OF CHEMISTRY. 
 
 309 
 
 of the fecond order. As an additional precau- 
 tion, the parts of thefe wheels which fupport 
 the axis of the beam are covered with plates of 
 polilhed rock-criftal. The whole of this machi- 
 nery is fixed to the top of the folid column of 
 wood BC, Fig. 1. To one extremity D of the 
 beam, a fcale P for holding weights is fufpend- 
 ed by a flat chain, which applies to the curva- 
 ture of the arc riDo , in a groove made for the 
 purpofe. To the other extremity E of the beam 
 is applied another flat chain, i k ;;z, fo con- 
 ftru&ed, as to be incapable of lengthening or 
 Ihortening, by being lefs or more charged with 
 weight ; to this chain, an iron trivet, with three 
 branches, a /, c /, and h /, is ftrongly fixed at t 9 
 and thefe branches fupport a large inverted jar 
 A, of hammered copper, of about 18 inches di- 
 ameter, and 20 inches deep. The whole of 
 this machine is reprefented in perfpe&ive, PI. 
 VIII. Fig. 1. and PI. IX. Fig. 2. and 4. give 
 perpendicular fe&ions, which fhow its interior 
 ftru&ure. 
 
 Round the bottom of the jar, on its outfide, 
 is fixed (PI. IX. Fig. 2.) a border divided into 
 compartments 1,2, 3, 4, &c. intended to re- 
 ceive leaden weights feparately reprefented 1, 
 2, 3, Fig. 3. Thefe are intended for increa- 
 fing the weight of the jar when a confiderable 
 preflure is requifite, as will be afterwards ex- 
 plained, though fuch neceflity feldom occurs. 
 
 The 
 
3 io ELEMENTS 
 
 The cylindrical jar A is entirely open below, 
 de 9 PI. IX. Fig. 4. ; but is clofed above with 
 a copper lid, ab c, open at b f 9 and capable of 
 being fhut by the cock g. This lid, as may be 
 feen by infpefting the figures, is placed a few 
 inches within the top of the jar to prevent the 
 jar from being ever entirely immerfed in the 
 water, and covered over. Were I to have this 
 inflrument made over again, I fliould caufe the 
 lid to be confiderably more flattened, fo as to 
 be almoft level. This jar or refervoir of air is 
 contained in the cylindrical copper veflel, 
 LMNO, PI. VIII. Fig. 1. filled with water. 
 
 In the middle of the cylindrical veflel LMNO/ 
 PI. IX. Fig. 4. are placed two tubes si , xy 9 
 which are made to approach each other at their 
 upper extremities ty $ thefe are made of fuch a 
 length as to rife a little above the upper edge 
 LM of the veflel LMNO, and when the jar 
 abcde touches the bottom NO, their upper ends 
 enter about half an inch into the conical hol- 
 low r b , leading to the flop-cock g . 
 
 The bottom of the veflel LMNO is repre- 
 sented PI. IX. Fig. 3. in the middle of which a 
 fmall hollow femifpherical cap is Soldered, which 
 may be confidered as the broad end of a funnel 
 reverfed ; the two tubes st 9 xy 9 Fig. 4 . are a- 
 dapted to this cap at s and x 9 and by this means 
 communicate with the tubes mm 9 nn 9 oo 9 pp 9 
 Fig. 3. which are fixed horizontally upon the 
 
 bottom 
 
OF CHEMISTRY, 
 
 3 ** 
 
 bottom of the veflel, and all of which terminate 
 in, and are united by, the fphericai cap sx. 
 Three of thefe tubes are continued out of the 
 veflel, as in PL VIII. Fig. i. The firfl: marked 
 in that figure 1, 2, 3, is inferted at its extremi- 
 ty 3, by means of an intermediate flop-cock 4, 
 to the jar V. which ftands upon the flielf of a 
 fmall pneumato- chemical apparatus GHIK, the 
 infide of which is fhown PL IX. Fig. 1. The 
 fecond tube is applied againfl the outfide of the 
 veflel LMNO from 6 to 7, is continued at 8, 9, 
 10, and at 1 1 is engaged below the jar V. The 
 former of thefe tubes is intended for conveying 
 gas into the machine, and the latter for con- 
 ducing fmall quantities for trials under jars. 
 The gas is made either to flow into or out of 
 the machine, according to the degree of preflure 
 it receives ; and this preflure is varied at plea- 
 fure, by loading the fcale P lefs or more, by 
 means of weights. When gas is to be introdu- 
 ced into the machine, the preflure is taken off, 
 or even rendered negative \ but, when gas is to 
 be expelled, a preflure is made with fuch de- 
 gree of force as is found neceflary. 
 
 The third tube 12, 13, 14, 15, is intended 
 for conveying air or gas to any neceflary place 
 or apparatus for combuftions, combinations, or 
 any other experiment in which it is required. 
 
 To explain the ufe of the fourth tube, I muff’ 
 enter into feme difcuflions. Suppofe the vef- 
 fel 
 
312 
 
 ELEMENTS 
 
 fel LMNO, PL VIII. Fig. i. full of water, and 
 the jar A partly filled with gas, and partly with 
 water ; it is evident that the weights in the ba- 
 fon P may be fo adjufted, as to occafion an ex- 
 act equilibrium between the weight of the bafon 
 and of the jar, fo that the external air fhall not 
 tend to enter into the jar, nor the gas to efcape 
 from it ; and in this cafe the water will Hand 
 exactly at the fame level both within and with- 
 out the jar. On the contrary, if the weight in 
 the bafon P be diminifhed, the jar will then 
 prefs downwards from its own gravity, and the 
 water will Hand lower within the jar than it 
 does without ; in this cafe, the included air or 
 gas will fuffer a degree of compreflion above 
 that experienced by the external air, exa&Iy 
 proportioned to the weight of a column of wa- 
 ter, equal to the difference of the external and 
 internal furfaces of the water. From thefe re- 
 flections, Mr Meufnier contrived a method of 
 determining the exaCt degree of preffure to 
 which the gas contained in the jar is at any 
 time expofed. For this purpofe, he employs a 
 double glafs fyphon 19, 20, 21, 22, 23, firmly 
 cemented at 19 and 23. The extremity 19 of 
 this fyphon communicates freely with the water 
 in the external veffel of the machine, and the 
 extremity 23 communicates with the fourth 
 tube at the bottom of the cylindrical veffel, and 
 fonfequently, by means of the perpendicular 
 
 tube 
 
OF CHEMISTRY. 
 
 3*3 
 
 tube st, PL IX. Fig. 4. with the air contained 
 in the jar. He likewife cements, at 1 6, PI. VIII. 
 Fig. 1. another glafs tube 16, 17, 18, which 
 ■ communicates at 16 with the water in the exte- 
 rior veflel LMNO, and, at its upper end 18, is 
 open to the external air. 
 
 By thefe feveral contrivances, it is evident 
 i that the water mull hand in the tube 16, 17, 
 1 8, at the fame level with that in the cittern 
 LMNO ; and, on the contrary, that, in the 
 branch 19, 20, 21, it mutt ttand higher or low- 
 er, according as the air in the jar is fubjedted to 
 j a greater or letter preflure than the external air. 
 
 To afcertain thefe differences, a brafs fcale divi- 
 | ded into inches and lines is fixed between thefe 
 i two tubes. It is readily conceived that, as air* 
 
 [ and all other elattic fluids, mutt increafe in 
 weight by compreflion, it is neceffary to know 
 , their degree of condenfation to be enabled to 
 l calculate their quantities, and to convert the 
 meafure of their volumes into correfpondent 
 weights ; and this object is intended to be ful- 
 filled by the contrivance now defcribed. 
 
 But, to determine the fpecific gravity of air 
 | Dr of gaffes, and to afcertain their weight in a 
 known volume, it is neceffary to know their 
 I temperature, as well as the degree of preflure 
 1 ander which they fubfift ; and this is accom- 
 f plifhed by means of a fmall thermometer, ttrong- 
 ly cemented into a brafs collet, which fcrews 
 R r into 
 
3 J 4 
 
 ELEMENTS 
 
 into the iid of the jar A, This thermometer 
 is reprefented feparately, Pi. VIII. Fig. 10. and 
 in its place 24, 25, Fig. 1. and PI. IX. Fig. 4. 
 The bulb is in the infide of the jar A, and its 
 graduated ftalk rifes on the outfide of the lid. 
 
 The practice of gazometry would {till have 
 laboured under great difficulties, without far- 
 ther precautions than thofe above defcribed. 
 When the jar A finks in the water of the ciflern 
 LMNO, it mufl lofe a weight equal to that of 
 the water which it difplaces ; and confequently 
 the compreffion which it makes upon the con- 
 tained air or gas mufl; be proportionally dimi- 
 niffied. Hence the gas furnilhed, during experi- 
 ments from the machine, will not have the fame 
 denfity towards the end that it had at the begin- 
 ning, as its fpecific gravity is continually dimi- 
 nifhing. This difference may, it is true, be de- 
 termined by calculation ; but this would have 
 occafioned fuch mathematical inveftigations as 
 mufl have rendered the ufe of this apparatus 
 both troublefome and difficult. Mr Meuf- 
 nier has remedied this inconvenience by the 
 following contrivance. A fquare rod of iron, 
 26 , 27, PI. VIII. Fig. 1. is raifed perpendicular 
 to the middle of the beam DE. This rod paffes 
 through a hollow box of brafs 28, which opens, 
 and may be filled with lead ; and this box is 
 made to Hide alongft the rod, by means of a 
 toothed pinioi* playing in a rack, fo as to raife 
 
 or 
 
OF CHEMISTRY. 
 
 3 r 5 
 
 or lower the box, and to fix it at fuch places as 
 is judged proper. 
 
 When the lever or beam DE (lands horizon- 
 tal, this box gravitates to neither fide ; but, 
 when the jar A finks into the ciftern LMNO, 
 fo as to make the beam incline to that fide, it is 
 evident the loaded box 28, which then pafl'es 
 beyond the center of fufpenfion, muil gravi- 
 tate to the fide of the jar, and augment its 
 prefiure upon the included air. This is in- 
 creafed in proportion as the box is raifed to- 
 wards 27, becaufe the fame weight exerts a 
 greater power in proportion to the length of 
 the lever by which it ads. Hence, by moving 
 the box 28 alongfi; the rod 26, 27, we can aug- 
 ment or diminilh the corredion it is intended 
 to make upon the prefiure of the jar ; and both 
 experience and calculation fhow that this may 
 be made to compenfate very exadly for the lols 
 of weight in the jar at all degrees of prelfure. 
 
 I have not hitherto explained the mod im- 
 portant part of the ufe of this machine, which 
 is the manner of employing it for afcertaining 
 the quantities of the air or gas furniflied during 
 experiments. To determine this with the molt 
 rigorous precifion, and likewife the quantity 
 fupplied to the machine from experiments, we 
 fixed to the arc which terminates the arm of 
 the beam E, PL VIII- Fig. 1. the brafs fedor 
 i divided into degrees and half degrees, 
 
 which 
 
3 i6 E L E M ENTS 
 
 which confequently moves in common with the 
 beam ; and the lowering of this end of the 
 beam is meafured by the fixed index 29, 30, 
 which has a Nonius giving hundredth parts of 
 a degree at its extremity 30. 
 
 The whole particulars of the different parts 
 of the above defcribed machine are reprefented 
 in Plate VIII. as follow. 
 
 Fig. 2. Is the flat chain invented by Mr 
 Vaucanfon, and employed for fufpending the 
 fcale or bafon P, Fig, 1 ; but, as this lengthens 
 or fhortens according as it is more or lefs load- 
 ed, it would not have anfwered for fufpending 
 the jar A, Fig. 1. 
 
 Fig. 5. Is the chain i k m 9 which in Fig. . 
 1. fuflains the jar A. This is entirely form- 
 ed of plates of poliflied iron interlaced into 
 each other, and held together by iron pins. 
 This chain does not lengthen in any fenfible de- 
 gree, by any weight it is capable of fupport- 
 ing.. 
 
 Fig. 6. The trivet, or three branched ftir- 
 rup, by which the jar A is hung to the ba- 
 lance, with the fcrew by which it is fixed in an 
 accurately vertical pofition. 
 
 Fig. 3. The iron rod 26, 27, which is fixed 
 perpendicular to the center of the beam, with 
 its box 28. 
 
 Fig. 7. & 8. The fri&ion- wheels, with the 
 plates of rock-criftal Z, as points of conta& 
 
 by 
 
OF CHEMISTRY. 
 
 3 l 7 
 
 by which the fri&ion of the axis of the lever of 
 the balance is avoided. 
 
 Fig, 4, The piece of metal which fupports 
 the axis of the fri&ion. wheels. 
 
 Fig. 9. The middle of the lever or beam, 
 with the axis upon which it moves. 
 
 Fig. io. The thermometer for determining 
 the temperature of the air or gas contained in 
 the jar. 
 
 When this gazometer is to be ufed, the cif- 
 tern or external veffel, LMNO, PL VIII. Fig. 1. 
 is to be filled with water to a determinate height, 
 which fhould be the fame in all experiments. 
 The level of the water fhould be taken when the 
 beam of the balance Hands horizontal ; this 
 level, when the jar is at the bottom of the cif* 
 tern, is increafed by all the water which it dif- 
 places, and is diminifhed in proportion as the 
 jar rifes to its highefl elevation. We next en- 
 deavour, by repeated trials, to difcover at what 
 elevation the box 28 muft be fixed, to render 
 the preffure equal in all fituations of the beam, 
 I fhould have faid nearly, becaufe this correc- 
 tion is not abfolutely rigorous ; and differences 
 of a quarter, or even of half a line, are not of 
 any confequence. This height of the box 28 
 is not the fame for every degree of preffure, but 
 varies according as this is of one, two, three, 
 or more, inches. All thefe fhould be regiftered 
 with great order and precifion. 
 
 We 
 
3i8 
 
 ELEMENTS 
 
 
 We next take a bottle which holds eight or 
 ten pints, the capacity of which is very accu- 
 rately determined by weighing the water it is 
 capable of containing. This bottle is turned 
 bottom upwards, full of water, in the cittern of 
 the pneurnato-chemical apparatus GHIK, Fig. i. 
 and is fet on its mouth upon the fhelf of the 
 apparatus, inftead of the glafs jar V, having the 
 extremity n of the tube 7, 8, 9, 10, 11, in- 
 serted into its mouth. The machine is fixed at 
 zero of prefiure, and the degree marked by the 
 index 30 upon the fe&or ml is accurately ob- 
 ferved ; then, by opening the ftopcock 8, and 
 prefiing a little upon the jar A, as much air is 
 forced into the bottle as fills it entirely. The 
 degree marked by the index upon the fe&or is 
 now obferved, and we calculate what number 
 of cubical inches correfpond to each degree. 
 We then fill a fecond and third bottle, and fo 
 on, in the fame manner, with the fame precau- 
 tions, and even repeat the operation feveral 
 times with bottles of different fizes, till at laft, 
 by accurate attention, w r e afeertain the exad 
 gage or capacity of the jar A, in all its parts ; 
 but it is better to have it formed at firft accu- 
 rately cylindrical, by which we avoid thefe cal- 
 culations and eftimates. 
 
 The infirument I have been deferibing was 
 conftru&ed with great accuracy and uncommon 
 fkill by Mr Meignie junior, engineer and phyfi- 
 
 cal 
 
OF CHEMISTRY. 
 
 3*9 
 
 cal inftrumcnt-maker. It is a moft valuable iru 
 ftrument, from the great number of purpofes to 
 which it is applicable ; and, indeed, there are 
 many experiments which are almoft impoffibie 
 to be performed without it. It becomes ex- 
 penfive, becaufe, in many experiments, fuch as 
 the formation of water and of nitric acid, it is 
 abfolutely neceffary to employ two of the fame 
 machines. In the prefent advanced {fate of che- 
 miftry, very expenfive and complicated inftru- 
 ments are become indifpenfibly neceffary for 
 afcertaining the analyfis and fynthefis of bodies 
 with the requifite precifion as to quantity and 
 proportion ; it is certainly proper to endeavour 
 to fimplify thefe, and to render them lefs coft- 
 ly ; but this ought by no means to be attempt- 
 ed at the expence of their conveniency of appli- 
 cation, and much lefs of their accuracy. 
 
 SECT. III. 
 
 Some other methods of meafuring the volume of 
 Gaffes* 
 
 The gazometer defcribed in the foregoing 
 fe&ion is too coftly and too complicated for be- 
 ing generally ufed in laboratories for meafuring 
 the gaffes, and is not even applicable to every 
 
 circumftance 
 
320 
 
 ELEMENTS 
 
 circumftance of this kind. In numerous feriea 
 of experiments, more fimple and more readily 
 applicable methods mud be employed. For this 
 purpofe I fhall defcribe the means I ufed before 
 I was in poffeflion of a gazometer, and which I 
 flill ufe in preference to it in the ordinary 
 courfe of my experiments. 
 
 Suppofe that, after an experiment, there is a 
 refiduum of gas, neither abforbableby alkali nor 
 water, contained in the upper part of the jar 
 AEF, PI. IV. Fig. 3. (landing on the (helf of a 
 pneumato-chemical apparatus, of which we wifh . 
 to afcertain the quantity, we mud firft mark the 
 height to which the mercury or water riles in 
 the jar with great exa&nefs, by means of flips 
 of paper parted in feveral parts round the jar. 
 
 If we have been operating in mercury, we be- 
 gin by difplacing the mercury from the jar, by 
 introducing water in its (lead. This is readily 
 done by filling a bottle quite full of water ; ha- 
 ving flopped it with your finger, turn it up, and • 
 introduce its mouth below the edge of the jar ; 
 then, turning down its body again, the mer- 
 cury, by its gravity, falls into the bottle, and 
 the water rifes in the jar, and takes the place 
 occupied by the mercury. When this is ac- 
 coinplilhed, pour fo much water into the cif- 
 tern ABCD as will ftand about an inch over tbs 
 ■furface of the mercury ; then pafs the difh BC, 
 
 PL V. Fig. 9. under the jar, and carry it to the 
 
 water 
 
OF CHEMISTRY. 321 
 
 water ciftern, Fig. 1. and 2. We here ex- 
 change the gas into another jar, which has 
 been previoufly graduated in the manner to be 
 afterwards defcribed ; and we thus judge of the 
 quantity or volume of the gas by means of the 
 degrees which it occupies in the graduated jar. 
 
 There is another method of determining the 
 volume of gas, which may either be fubflituted 
 in place of the one above defcribed, or may be 
 ufefully employed as a correction or proof of 
 that method. After the air or gas is exchanged 
 from the firfl jar, marked with (lips of paper, 
 into the graduated jar, turn up the mouth of 
 the marked jar, and fill it with water exactly to 
 the marks EF, PL IV. Fig. 3. and by weighing 
 the water we determine the volume of the air or 
 gas it contained, allowing one cubical foot, or 
 1728 cubical inches, of water for ea-ch 70 pounds, 
 French weight. 
 
 The manner of graduating jars for this pur- 
 pofe is very eafy, and we ought to be provided 
 with feveral of different fizes, and even feveral 
 of each fize, in cafe of accidents. Take a tall, 
 narrow, and ftrong glafs jar, and, having filled 
 it with water in the ciftern, Pl.V. Fig. 1. place it 
 upon the fhelf ABCD ; we ought always to ufe 
 the fame place for this operation, that th level 
 
 I of the fhelf may be always exa&ly limilai, by 
 which almoft the only error to which this pro- 
 cefs is liable will be avoided. Then take a nar- 
 S s 
 
 row 
 
J22 
 
 ELEMENTS 
 
 row mouthed phial which holds exa&ly 6 oz. 
 3 gros 6 1 grs. of water, which correfponds to 
 io cubical inches. If you have not one exact- 
 ly of this dimenfion, choofe one a little larger, 
 and diminifh its capacity to the fize requifite, 
 by dropping in a little melted wax and rofin. 
 This bottle ferves the purpole of a ftandard for 
 gaging the jars* Make the air contained in 
 this bottle oafs into the jar, and mark exadly 
 the place to which the water has defcended ; 
 add another meafure of air, and again mark 
 the place of the water, and fo on, till all the 
 water be diiplaced. It is of great coniequence 
 that, during the courfe of this operation, the 
 bottle and jar be kept at the fame temperature 
 with the water in the cittern j and for this rea- 
 fon, we mutt avoid keeping the hands upon ei- 
 ther as much as poflibie ; or, if we fufped they 
 have been heated, we mutt cool thr.n.by means 
 pf the water in the cittern. The height of the 
 barometer and thermometer during this experi- 
 ment is of no confequence* 
 
 When the matks have been thus afcertained 
 upon the jar for every ten cubical inches, we 
 engrave a fcale upon one of irs Tides, by means 
 of a diamond pencil. Glafs tubes are gradu- 
 ated in the fame manner for ufing in the mer- 
 curial apparatus, only they mutt be divided in- 
 to cubical inches, and tenths of a cubical inch. 
 The bottle ufed for gaging thefe mutt Tlr ' M 
 
OF CHEMISTRY. 
 
 3 2 3 
 
 : S cz. 6 grcs 25 grs. of mercury, which exactly 
 correfponds to a cubical inch of that metai. 
 
 The method of determining the volume of 
 air or gas, by means of a graduated jar, has the 
 advantage of not requiring any correction for 
 the difference of height between the furface of 
 the water within the jar, and in the ciftern ; 
 but it requires corrections with refpeCt to the 
 height of the barometer and thermometer. But, 
 when we afcertain the volume of air by weigh- 
 ing the water which the jar is capable of con- 
 taining, up to the marks EF, it is neceffary to 
 make a farther correction, for the difference be- 
 tween the furface of the water in the ciftern, 
 and the height to which it rifes within the jar-. 
 This will be explained in the fifth feCtion of this 
 chapter. 
 
 SECT. IV. 
 
 Of the method of Separating the different Gaffes 
 from each other . 
 
 As experiments often produce two, three, of 
 more fpecies of gas, it is neceffary to be able to 
 leparate thefe from each other, that we may af- 
 certain the quantity and fpecies of each. Sup- 
 pofe that under the jar A, PI. IV. Fig. 3. is 
 
 contained 
 
3 2 4 ELEMENTS 
 
 contained a quantity of different gaffes mixei 
 together, and (landing over mercury, we begin 
 by marking with flips of paper, as before direc- 
 ted, the height at which the mercury Hands 
 within the glafs ; then introduce about a cubi- 
 cal inch of water into the jar, which will fwim 
 over the furface of the mercury : If the mixture 
 of gas contains any muriatic or fulphurous acid 
 gas, a rapid and confiderable abforption will 
 inftantly take place, from the ftrong tendency 
 thefe two gaffes have, eipecially the former, to 
 combine with, or be abforbed by water. If the 
 water only produces a flight abforption of gas 
 hardly equal to its own bulk, we conclude, that 
 the mixture neither contains muriatic acid, ful- 
 phuric acid, or ammoniacal gas, but that it con- 
 tains carbonic acid gas, of which water only ab- 
 forbs about its own bulk. To afcertain this 
 conjecture, introduce fome folution of cauflic 
 alkali, and the carbonic acid gas will be gra- 
 dually abforbed in the courfe of a few hours ; 
 it combines with the cauflic alkali or potafh, 
 and the remaining gas is left almofl perfefily 
 free from any fenfible refiduum of carbonic acid 
 gas. 
 
 After each experiment of this kind, we mud 
 carefully mark the height at which the mercury 
 ftands within the jar, by flips of paper paflec 
 on, and varnifhed over when dry, that they ma] 
 not be wafhed off when placed in the water ap 
 
 paratus 
 
OF CHEMISTRY, 
 
 ys 
 
 paratus. It is likewife neceffary to regifter the 
 difference between the furface of the mercury in 
 the ciftern and that in the jar, and the height of 
 the barometer and thermometer, at the end of 
 each experiment. 
 
 When all the gas or gaffes abforbable by wa- 
 ter and potafh are abforbed, water is admitted 
 into the jar to difplace the mercury ; and, as is 
 defcribed in the preceding fe&ion, the mercury 
 in the ciftern is to be covered by one or two 
 inches of water. After this, the jar is to be 
 tranfported by means of the flat difh BC, PI. V. 
 Fig. 9. into the water apparatus ; and the quan- 
 tity of gas remaining is to be afcertained by 
 changing it into a graduated jar. After this, 
 fmall trials of it are to be made by experiments 
 in little jars, to afcertain nearly the nature of 
 the gas in queftion. For inftance, into a fmall 
 jar full of the gas, Fig. 8. PI. V. a lighted taper 
 is introduced j if the taper is not immediately 
 extinguifhed, we conclude the gas to contain 
 oxygen gas ; and, in proportion to the bright- 
 nefs of the flame, we may judge if it contain 
 lefs or more oxygen gas than atmofpheric air 
 contains. If, on the contrary, the taper be in- 
 ftantly extinguifhed, we have ftrong reafon to 
 prefume that the refiduum is chiefly compofed 
 of azotic gas. If, upon the approach of the ta- 
 per, the gas takes fire and burns quietly at the 
 furface with a white flame, we conclude it to be 
 
 pure 
 
326 ELEMENTS 
 
 pure hydrogen gas ; if this flame is blue, We 
 judge it confifts of carbonated hydrogen gas ; 
 and, if it takes fire with a fudden deflagration, 
 that it is a mixture of oxygen and hydrogen 
 gas. If, again, upon mixing a portion of the 
 refiduum with oxygen gas, red fumes are pro- 
 duced, we conclude that it contains nitrous gas. 
 
 Thefe preliminary trials give feme general 
 knowledge of the properties of the gas, and 
 nature of the mixture, but are not fufficient to 
 determine the proportions and quantities of the 
 feveral gaffes of which it is compofed. For this 
 purpofe all the methods of analyfis muff be em- 
 ployed ; and, to direft thefe properly, it is of 
 great ufe to have a previous approximation by 
 the above methods. Suppofe, for inftance, we 
 know that the refiduum confifts of oxygen and 
 azotic gas mixed together, put a determinate 
 quantity, 100 parts, into a graduated tube of 
 ten or twelve lines diameter, introduce a folution 
 of fulphuret of potafh in contaft with the gas, 
 and leave them together for fome days ; the ful- 
 phuret abforbs the whole oxygen gas, and leaves 
 the azotic gas pure. 
 
 If it is known to contain hydrogen gas, a de- 
 terminate quantity is introduced into Volta’s 
 eudiometer alongft with a known proportion of 
 hydrogen gas ; thefe are deflagrated together by 
 means of the ele&rical fpark ; frefh portions of 
 oxygen gas are fucceffively added, till no far- 
 ther 
 
OF CHEMISTRY. 
 
 3*t 
 
 eher deflagration takes place, and till the great- 
 eft poflible diminution is produced. By this 
 procefs water is formed, which is immediately 
 abforbed by the water of the apparatus ; but, if 
 the hydrogen gas contain charcoal, carbonic 
 acid is formed at the fame time, which is not 
 abforbed fo quickly; the quantity of this is 
 readily afcertained by afiifting its abforption, by 
 means of agitation. If the refiduum contains 
 nitrous gas, by adding oxygen gas, with which 
 it combines into nitric acid, we can very nearly 
 afcertain its quantity, from the diminution pro- 
 duced by this mixture. 
 
 I confine myfelf to thefe general examples, 
 which are fufficient to give an idea of this kind 
 of operations ; a whole volume would not ferve 
 to explain every poflible cafe. It is neceffary to 
 become familiar with the analyfis of gaffes by 
 long experience ; we muft even acknowledge 
 that they moftly poflfefs fuch powerful affinities 
 to each other, that we are not always certain of 
 having feparated them completely. In thefe 
 cafes, we muft vary our experiments in every 
 poflible point of view, add new agents to the 
 combination, and keep out others, and continue 
 our trials, till we are certain of the trqth and 
 exa&itude of our conclufions. 
 
 SECT. 
 
32 * 
 
 ELEMENTS 
 
 SECT. V. 
 
 Of the neceffary corrections upon the volume of the 
 Gaffes , according to the preffure of the At mo* 
 fphere* 
 
 Ail elaftic fluids are compreflible or conden- 
 fible in proportion to the weight with which 
 they are loaded. Perhaps this law, which is 
 afcertained by general experience, may fuffer 
 fome irregularity when thefe fluids are under a 
 degree of condenfation almoft fufficient to re- 
 duce them to the liquid date, or when either in 
 a ftate of extreme rarefaction or condenfation ; 
 but we feldom approach either of thefe limits 
 with moft of the gafles which we fubmit to our 
 experiments. I underhand this proportion of 
 gafles being compreflible, in proportion to their 
 fuperincumbent weights, as follows : 
 
 A barometer, which is an inftrument gene- 
 rally known, is, properly fpeaking, a fpecies of 
 fyphon, ABCD, PI. XII. Fig. 16. whofe leg AB 
 is filled with mercury, whilft the leg CD is full 
 of air. If we fuppofe the branch CD indefinitely 
 continued till it equals the height of our atmo- 
 fphere, we can readily conceive that the baro- 
 meter is, in reality, a fort of balance, in which 
 * a 
 
OF CHEMISTRY. 
 
 3*9 
 
 a column of mercury flands in equilibrium with 
 a column of air of the fame weight. But it is 
 unneceflary to prolongate the branch CD to 
 fuch a height, as it is evident that the barome- 
 ter being immerfed in air, the column of mer- 
 cury AB will be equally in equilibrium with a 
 column of air of the fame diameter, though the 
 leg CD be cut off at C, and the part CD be ta- 
 ken away altogether. 
 
 The medium height of mercury in equili- 
 brium with the weight of a column of air, 
 from the higheft part of the atmofphere to the 
 furface of the earth is about twenty-eight French 
 inches in the lower parts of the city of Paris ; 
 or, in other words, the air at the furface of the 
 earth at Paris is ufually prelfed upon by a 
 weight equal to that of a column of mercury 
 twenty-eight inches in height. I mud be un- 
 derftood in this way in the feveral parts of this 
 publication when talking of the different gaffes, 
 as, for indance, when the cubical foot of oxy- 
 gen gas is faid to weigh 1 cz. 4 gros , under 28 
 inches prelfure. The height of this column of 
 mercury, fupported by the prelfure of the air, 
 diminifhes in proportion as we are elevated a- 
 bove the furface of the earth, or rather above 
 the level of the fea, becaufe the mercury can 
 only form an equilibrium with the column of 
 air which is above it, and is not in the fmalleft 
 T t degree 
 
33o ELEMENTS 
 
 degree affected by the air which is below its 
 level. 
 
 Jn what ratio does the mercury in the baro- 
 meter defcend in proportion to its elevation ? 
 or, what is the fame thing, according to what 
 law or ratio do the feveral ftrata of the atmo r 
 fphere decreafe in denfity ? This queftion, 
 which has exercifed the ingenuity of natural 
 philofophers during laft century, is confiderably 
 elucidated by the following experiment. 
 
 If we take the glaf? fyphon ABCDE, PI. XIL 
 Fig. 17. fhut at E, and open at A, and intro- 
 duce a few drops of mercury, fo as to intercept 
 the communication of air between the leg AB 
 and the leg BE, it is evident that the air con- 
 tained in BCDE is preffed upon, in common 
 with the whole furrounding air, by a weight or 
 column of air equal tq 28 inches of mercury. 
 But, if we pour 28 inches of mercury into the 
 leg AB, it is plain the air in the branch BCDE 
 will new be preffed upon by a weight equal tq 
 twice ^8 inches of mercury, or twice the weight 
 of the atmofphere ; and experience (hows, that, 
 in this cafe, the included air, inftead of filling 
 the tube from B to E, only occupies from C to 
 E, or exaftly one half of the fpace it filled be- 
 fore. If to this firft column of mercury we add 
 two other portions of 28 inches each, in the 
 branch AB, the air in the branch BCDE will 
 be preffed upon by four times the weight of the 
 
 atmofphere. 
 
OF CHEMISTRY. 
 
 33 * 
 
 atmofphere, or four times the weight of 28 
 inches of mercury, and it will then only fill the 
 fpace from D to E, or exactly one quarter of 
 the fpace it occupied at the commencement of 
 the experiment. From thefe experiments, which 
 may be infinitely varied, has been deduced as a 
 general law of nature, which feems applicable 
 to all permanently elaftic fluids, that they di- 
 minifh in volume in proportion to the weights 
 with which they are prefled upon 5 or, in other 
 words, “ the volume of all elajlic fluids is in the 
 “ inverfe ratio of the weight by which they are 
 46 compreffed” 
 
 The experiments which have been made for 
 meafuring the heights of mountains by means 
 of the barometer, confirm the truth of tiieie 
 deductions 7 and, even fuppofmg them in foine 
 degree inaccurate, thefe differences are fo ex- 
 tremely fmall, that they may be reckoned as 
 nullities in chemical experiments. When this 
 law of the compreflion of elaftic fluids is once 
 well underftood, it becomes eafily applicable 
 to the corrections neceffary in pneumato- che- 
 mical experiments upon the volume of gas, 
 in relation to its preffure. Thefe corrections 
 are of two kinds, the one relative to the varia- 
 tions of the barometer, and the other for the 
 column of water or mercury contained in the 
 jars. I fhail endeavour to explain thefe by ex- 
 amples* beginning with the mod limple cafe. 
 
 Suppofc 
 
33 2 ELEMENTS 
 
 Suppofe that ioo cubical inches of oxygen 
 gas are obtained at io° (54.5 0 ) of the thermo- 
 meter, and at 28 inches 6 lines of the barome- 
 ter, it is required to know what volume the 1 00 
 cubical inches of gas would occupy, under the 
 preffure of ‘28 inches *, and what is the exad 
 weight of the 100 inches of oxygen gas ? Let 
 the unknown volume, or the number of inches 
 this gas would occupy at 28 inches of the baro- 
 meter, be expreffed by x ; and, fince the vo- 
 lumes are in the inverfe ratio of their fuperin- 
 cumbent weights, we have the following ftate- 
 ment : 100 cubical inches is to x inversely as 
 28.5 inches of preffure is to 28.0 inches ; or 
 dire&ly 28' : 28.5 ; : 100 : x s= 101.786 — cubi- 
 cal inches, at 28 inches barometrical preffure; 
 that is to fay, the fame gas or air which at 28.5 
 inches of the barometer occupies 100 cubical 
 inches of volume, will occupy 101.786 cubical 
 inches when the barometer is at 28 inches. It 
 is equally eafy to calculate the weight of this 
 gas, occupying 100 cubical inches, uhder 28.5 
 inches of barometrical preffure ; for, as it cor- 
 
 refponds 
 
 * According to the proportion of 114 to 107, given 
 between the French and Engiifh foot, 28 inches of 
 the French barometer are equal to 29.83 inches of the 
 Englifh. Directions will be found in the appendix for 
 converting all the French weights and meafures ufed 
 in this work into correfponding Englifh denominations. 
 — E. 
 
OF CHEMISTRY. 
 
 33 $ 
 
 refponds to 101.786 cubical inches at the pref- 
 1'ure of 28, and as, at this preflure, and at io° 
 (54.5 0 ) of temperature, each cubical inch of 
 oxygen gas weighs half a grain, it follows, that 
 100 cubical inches, under 2 £.5 barometrical 
 preflure, mull weigh 50.893 grains. This con- 
 cluflon might have been formed more dire&ly, 
 as, fince the volume of elaftic fluids is in the 
 inverfe ratio of their compreflion, their weights 
 muft be in the direct ratio of the fame compref- 
 flon : Hence, fince 100 cubical inches weigh 
 50 grains, under the preflure of 28 inches, we 
 have the following ftatement to determine the 
 weight of 100 cubical inches of the fame gas as 
 28.5 barometrical preflure, 28 : 50 : : 28.5 : x > 
 the unknown quantity, = 50.893. 
 
 The following cafe is more complicated : 
 Suppofe the jar A, PI. XII. Fig. 18. to contain 
 a quantity of gas in its upper part ACD, the 
 reft of the jar below CD being full of mercury, 
 and the whole (landing in the mercurial bafon 
 or refervoir GH 1 K, filled with mercury up to 
 EF, and that the difference between the furface 
 CD of the mercury in the jar, and EF, that in 
 the ciftern, is fix inches, while the barometer 
 (lands at 27.5 inches. It is evident from thefe 
 data, that the air contained in ACD is preffed 
 upon by the weight of the atmofphere, diminifli- 
 ed by the weight of the column of mercury CE, 
 or by 27.5 — 6 = 21.5 inches of barometrical 
 
 preflure* 
 
334 
 
 ELEMENTS 
 
 
 preffure. This air is therefore lefs compreffed 
 than the atmofphere at the mean height of the 
 barometer, and confequently occupies more 
 fpace than it would occupy at the mean pref- 
 fure, the difference being exadtly proportional 
 to the difference between the compreffmg 
 weights. If, then, upon meafuring the fpace 
 ACD, it is found to be 120 cubical inches, it 
 muff be reduced to the volume which it would 
 occupy under the mean preffure of 28 inches. 
 This is done by the following ftatement : 
 120 : x, the unknown volume, : : 21.5 : 28 in- 
 
 bical inches. 
 
 In thefe calculations we may either reduce 
 the height of the mercury in the barometer, 
 and the difference of level in the jar and bafon, 
 into lines or decimal fra&ions of the inch ; but 
 
 cimai iracuons 01 me mciu 
 
 In experiments performed in the water-appa- 
 ratus, we muff make iimilar corre&ions to pro- 
 cure rigoroufly exadt refults, by taking into ac- 
 count, and making allowances for the difference 
 of height of the water within the jar above the 
 furface of the water in the ciftern. But, as the 
 
 verfely ; this gives tc = 
 
 120 x 21.5 
 2b 
 
 = 92.143 cu- 
 
 preffure 
 
OF CHEMISTRY. 
 
 335 
 
 preffure o£ the atmofphere is expreffed in inches 
 .and lines of the mercurial barometer, and, as 
 homogeneous quantities only can be calculated 
 together, we mull reduce the obferved inches 
 and lines of water into correfpondent heights of 
 :he mercury. I have given a table in the ap- 
 pendix for this converfion, upon the fuppofition 
 hat mercury is 1 3*568 1 times heavier than water. 
 
 SECT. VI. 
 
 If Corrections relative to the Degrees of the Ther- 
 mometer. 
 
 In ascertaining the weight of gaffes, befides 
 •educing them to a mean of barometrical pref- 
 ure, as dire&ed in the preceding fe&ion, we 
 null likewife reduce them to a Standard ther- 
 nometrical temperature ; becaufe, all elaflic 
 luids being expanded by heat, and condenfed 
 3y cold, their weight in any determinate vo- 
 ume is thereby liable to confiderable altera- 
 ions. As the temperature of io° (54*5°) is a 
 nedium between the heat of Summer and the 
 :old of winter, being the temperature of fub- 
 erraneous places, and that which is moll eafily 
 ipproached to at all feafons, I have chofen that 
 iegree as a mean to which I reduce air or gas 
 in this Species of calculation, 
 
 Mr 
 
' 3$6 ELEMENTS 
 
 Mr de Luc found that atmofpheric air was 
 increafed yfy part of its bulk, by each degree 
 of a mercurial thermometer, divided into 81 
 degrees, between the freezing and boiling 
 points ; this gives part for each degree of 
 Reaumur’s thermometer, which is divided into 
 80 degrees between thefe two points. The ex- 
 periments of Mr Monge feem to make this di- 
 latation lefs for hydrogen gas, which he thinks 
 is only dilated We have not any exaft ex- 
 periments hitherto published refpe&ing the ra- 
 tio of dilatation of the other gaffes ; but, from 
 the trials which have been made, their dilata- i 
 tion feems to differ little from that of atmo- 
 fpheric air. Hence I may take for granted, till 
 farther experiments give us better information 
 upon this fubjeft, that atmofpherical air is dila- 
 ted part, and hydrogen gas part for 
 each degree of the thermometer ; but, as there 
 is dill great uncertainty upon this point, we 
 ought always to operate in a temperature as I 
 near as poffible to the ftandard of io°, (54.5 0 ) \ 
 by this means any errors in corre&ing the 
 weight or volume of gaffes by reducing them to 
 the common ftandard, will become of little mo- 
 ment. 
 
 The calculation for this corre&ion is ex- 
 tremely eafy. Divide the obferved volume of 
 air by 210, and multiply the quotient by the 
 degrees of temperature above or below io c 
 
 ( 54 - 5 "> 
 
OF CHEMISTRY. 
 
 337 
 
 (S4 , 5°) < This correction is negative when the 
 actual temperature is above the Itandard and 
 pofttive when below. By the ule of logarith- 
 mical tables this calculation is much facilita- 
 ted *. 
 
 SECT. VII. 
 
 Example for calculating the Corrections relative to 
 the Variations of Preffure and Temperature . 
 
 ■ - \ 
 
 C A 3 E. 
 
 In the jar A, PI. IV. Fig* 3. (landing in a 
 water apparatus, is contained 353 cubical inch-* 
 es of air ; the furface of the water within the 
 jar at EF is 4- inches above the water in the 
 cittern, the barometer is at 27 inches lines, 
 and the thermometer at 15 0 (65.75°). Having 
 burnt a quantity of phofphorus in^the air, by 
 which concrete phofphoric add is produced, the 
 air after the combuftion occupies 295 cubical 
 U u inches, 
 
 * When Fahrenheit’s thermometer is employed, the 
 dilatation by each degree rrmft be frnaller, in the pro 
 portion of 1 to 2.25, becaufe each degree of Reaumur’s 
 fcale contains 2.25 degrees of Fahrenheit ; hence \v z 
 mull divide by 472.5, and finish the reft of the calcu- 
 lation as above.— E. 
 
338 ELEMENT S 
 
 inches, the water within the jar {lands 7 inched 
 above that in the cittern, the barometer is at 27 
 inches 9^ lines, and the thermometer at 16® 
 (68°). It is required from thefe data to deter- 
 mine the a&ual volume of air before and af- 
 ter combuftion, and the quantity abforbed du- 
 ring the procefs. 
 
 Calculation before Combujlion - 
 
 t /. . 
 
 The air in the jar before combuftion was 353 
 cubical inches, but it was only under a barome- 
 trical preffure of 2 7 inches 9-f lines ; which, re- 
 duced to decimal fractions by Tab. I. of the 
 Appendix, gives 27.79167 inches; and from 
 this we mutt deduct the difference of 4 ~ inches 
 of water, which, by Tab. II. correfponds to- 
 0.33.1 66 inches of the barometer; hence the 
 real preffure of the air in the jar is 27.46001. 
 As the volume of elaftic fluids diminifh in the 
 iftverfe ratio of the comprefling weights, we 
 have the following ftatement to reduce the 353. 
 inches to the volume the air would occupy at 
 28 inches barometrical preffure. 
 
 353 : the unknown volume, :: 27.46001:28. 
 
 _ T 353x27.46001 
 
 lienee, x — — — yjp — — = 340.192 cubical 
 
 inches, which is the volume the fame quantity 
 of air would have occupied at 2& inches of the 
 barometer* 
 
 \ 
 
 The 
 
OF CHEMISTRY. 
 
 339 
 
 The 2 ioth part of this corrected volume is 
 1.65, which, for the five degrees of temperature 
 above the ftandard gives 8.255 cubical inches; 
 
 and, as this correction is fubflra&ive, the real 
 corre&ed volume of the air before combustion 
 is 337.942 inches. 
 
 lation upon the volume of 
 we find its barometrical 
 ~ °*5 I 593 = 27.25 490. 
 
 preffure of 28 inches, 295 : x : : 27.77083 : 28 
 
 The 2 10th part of this corrected volume is 
 1.368, which, multiplied by 6 degrees of ther- 
 mometrical difference, gives the fubtractive 
 corre&ion for temperature 8.208, leaving the 
 actual corrected volume of air after combuflion 
 278.942 inches. 
 
 The corrected volume before combuf- 
 
 tion ^ . . . . . 337.942 
 
 Thtto remaining after combuflion . 278.942 
 
 Volume abforbed during combuflion 59.000. 
 
 Calculation after Combuftmi. 
 
 volume of air under the 
 
 inverfely ; or, x = 
 
 29? X 27.2 C 4 QO 
 28 
 
 = 287.150. 
 
 Refult. 
 
 SEC T 
 
340 ELEMENTS 
 
 SECT. VIIL 
 
 Method of determining the Ahfolute Gravity of the 
 different Gaffes . 
 
 Take a large balloon A, PL V. Fig. i o. capable 
 of holding 17 or 18 pints, or about half a cu- 
 bical foot, having the brafs cap bcde flrongly ce- 
 mented to its neck, and to which the tube and 
 ft op-cock fg is fixed by a tight ferew. This ap- 
 paratus is connoted by the double fetew re- 
 prefented feparafely at Fig. 12. to the jar BCD, 
 Fig. 10. which rouft be fome pints larger in di- 
 menfioris than the balloon This j tr is open at 
 top, and is furnifhed with the brafs cap h i 9 and 
 flop-cock / nu One of thefe flop cocks is re- 
 prefented feparately at Fig. 1 * 
 
 We firfl determine the exaS opacity of the 
 balloon by filling it with wa i, and weighing it 
 both full and empty. When emptied of water, 
 it is dried with a cloth introduced through its 
 neck d e 9 and the lafl remains of moiflure are 
 removed by exhaufling it once or twice in ai} 
 air-pump. 
 
 When the weight of any gas is to be afeer.- 
 tained, this apparatus is ufed as follows : Fix 
 the balloon A to the plate of an air-pump by 
 means of the ferew of the flop-cock / g 9 which is 
 
 left 
 
OF CHEMISTRY. 34* 
 
 left open ; the balloon is to be exhaufted as com- 
 pletely as poffible, obferving carefully the de- 
 gree of exhauftion by means of the barometer 
 attached to the air-pump. When the vacuum is 
 formed, the flop-cock fg is fhut, and the weight 
 of the balloon determined with the moft fcrupu- 
 lous exa&itude. It is then fixed to the jar 
 BCD, which we fuppofe placed in water in 
 the fhelf of the pneumato-chemical apparatus 
 Fig. 1. ; the jar is to be filled with the gas we 
 mean to weigh, and then, by opening the flop- 
 cocks fg and l m , the gas afcends into the bal- 
 loon, whilft the water of the ciflern rifes at the 
 fame time into the jar. To avoid very trouble- 
 fome corrections, it is neceffary, during this firft 
 part of the operation, to fink the jar in the cif- 
 tern till the furfaces of the water within the jar 
 and without exactly correfpond. The flop- 
 cocks are again fhut, and the balloon being un- 
 fcrewed from its connexion with the jar, is to 
 be carefully weighed ; the difference between 
 this weight and that of the exhaufted balloon is 
 the precife weight of the air or gas contained in 
 the balloon. Multiply this weight by 1728, the 
 number of cubical inches in a cubical foot, and 
 divide the product by the number of cubical 
 inches contained in the balloon, the quotient is 
 the weight of a cubical foot of the gas or air 
 lubmitted to experiment. 
 
 Exacf 
 
34 * 
 
 ELEMENTS 
 
 Exatt account mud be kept of the barome* 
 trical height and temperature of the thermome- 
 ter during the above experiment ; and from 
 thefe the refulting weight of a cubical foot is 
 eafily corre&ed to the dandard of 28 inches and 
 10', as directed in the preceding fe&ion. The 
 fmall portion of air remaining in the balloon af- 
 ter forming the vacuum mud likewife be at- 
 tended to, which is eafily determined by the 
 barometer attached to the air-pump. If that ba- 
 rometer, for indance, remains at the hundredth 
 part of the height it dood at before the vacuum 
 was formed, we conclude that one hundredth 
 part of the air originally contained remained in 
 the balloon, and confequently that only of 
 gas was introduced from the jar into the bal- 
 loon. 
 
 CHAP. 
 
PF CHEMISTRY. 
 
 345 
 
 CHAP. III. 
 
 Defcription of the Calorimeter , or Apparatus for 
 meafuring Caloric . 
 
 T H E calorimeter, or apparatus for meafu- 
 ring the relative quantities of heat con- 
 tained in bodies, was defcribed by Mr de la 
 Place and me in the Memoirs of the Academy 
 
 I for 1780, p. 355. and from that Eflay the ma- 
 terials of this chapter are extra&ed. 
 
 If, after having cooled any body to the free-, 
 zing point, it be expofed in an atmofphere of 
 
 I 25 0 ($8.25°), the body will gradually become 
 heated, from the furface inwards, till at laft it 
 acquire the fame temperature with the fur- 
 rounding air. But, if a piece of ice be placed 
 in the fame fituation, the circumftances are 
 
 i quite different ; it does not approach in the 
 fmalleft degree towards the temperature of the 
 circumambient air, but remains conftantly at 
 Zero (32 0 ), or the temperature of melting ice, 
 till the lafl portion of ice be completely melt- 
 ed. 
 
 This phenomenon is readily explained ; as y 
 to melt ice, or reduce it to water, it requires to> 
 be combined with a certain portion of caloric * 
 
 the 
 
§44 ELEMENTS 
 
 the whole caloric attra&ed from the furround- 
 ing bodies, is arrefled or fixed at the furface or 
 external layer of ice which it is employed to dif- 
 folve, and combines with it to form water ; the 
 next quantity of caloric combines with the fe- 
 cond layer to diffolve it into water, and fo oil 
 fucceflively till the whole ice be diffolved or 
 converted into water by combination with calo- 
 ric, the very laft atom (till remaining at its for- 
 mer temperature, becaufe the caloric has never 
 penetrated fo far as long as any intermediate ice 
 remained to melt. 
 
 Upon thefe principles, if we conceive a hol- 
 low fphere of ice at the temperature of Zero 
 (3 2 0 ) placed in an atmofphere io° (54.5°^, and 
 containing a fubftance at any degree of tempe- 
 rature above freezing, it follows, iff, That the 
 heat of the external atmofphere cannot penetrate 
 into the internal hollow of the fphere of ice $ 
 adly, That the heat of the body placed in the 
 hollow of the fphere cannot penetrate outwards 
 beyond it, but will be (topped at the internal 
 furface, and continually employed to melt fuc- 
 ceflive layers of ice, until the temperature of 
 the body be reduced to Zero (32°)* by having 
 all its fuperabundant caloric above that tempe- 
 rature carried off by the ice. If the whole wa- 
 ter, formed within the fphere of ice during the 
 reduction of the temperature of the included 
 body to Zero, be carefully colle&ed, the weight 
 . . of 
 
OF CHEMISTRY. 
 
 345 
 
 of the water will be exaftly proportional to the 
 quantity of caloric loft by the body in palling 
 from its original temperature to that of melting 
 ice ; for it is evident that a double quantity of 
 caloric would have melted twice the quantity 
 of ice ; hence the quantity of ice melted is a 
 very exa& meafure of the quantity of caloric 
 employed to produce that effett, and conse- 
 quently of the quantity loft by the only fub- 
 ftance that could poffibly have Supplied it. 
 
 I have made this fuppofition of what would 
 take place in a hollow Sphere of ice, for the pur- 
 pofe of more readily explaining the method ufed 
 in this Species of experiment, which was firft 
 conceived by Mr de la Place. It would be dif- 
 ficult to procure fuch fpheres of ice, and incon- 
 venient to make ufe of them when got ; but, by 
 means of the following apparatus, we have re- 
 medied that defeft. I acknowledge the name 
 of Calorimeter, which I have given it, as de- 
 rived partly from Greek and partly from Latin* 
 is in Some degree open to criticifm ; but, in mat- 
 ters of Science, a flight deviation from ftrict ety- 
 mology, for the fake of giving diftin&nefs of 
 idea, is excufable ; and I could not derive the 
 name entirely from Greek without approaching 
 too near to the names of known instruments 
 employed for other purpofes. 
 
 The calorimeter is reprefented in PI. VI. It is 
 Shown in perfpe&ive at Fig. i. and its interior 
 X x ftru&ure 
 
ELEMENTS 
 
 3+5 
 
 flru&ure is engraved in Fig. 2. and 3. ; the for- 
 mer being a horizontal, and the latter a perpen- 
 dicular fedtion. Its capacity or cavity is di- 
 vided into three parts, which, for better diftinc- 
 tion, I fhall name the interior, middle, and ex- 
 ternal cavities. The interior cavity / f ff, Fig. 4. 
 into which the fubftances fabmitted to experi- 
 ment are put, is compofed of a grating or cage 
 of iron wire, fupported by feveral iron bars ; its 
 opening or mouth LM, is covered by the lid 
 HG, of the fame materials. The middle cavi- 
 ty b b b b , Fig. 2. and 3. is intended to contain 
 the ice which furrounds the interior cavity, and 
 which is to be melted by the caloric of the fub- 
 flance employed in the experiment. The ice is 
 fupported by the grate m m at the bottom of the 
 cavity, under which is placed the lieve n n . 
 Thefe two are reprefented feparately in Fig. 5. 
 and 6. 
 
 In proportion as the ice contained in the 
 middle cavity is melted, by the caloric difenga- 
 ged from the body placed in the interior cavity, 
 the water runs through the grate and fieve, and 
 falls through the conical funnel ccd , Fig. 3. and 
 tube #y, into the receiver F, Fig. 1. This wa- 
 ter may be retained or let out at pleafure, by 
 means of the flop-cock u. The external cavity 
 aaaa , Fig. 2. and 3. is filled with ice, to pre- 
 vent any effedl upon the ice in the middle ca- 
 vity from the heat of the furrounding air, and 
 
 the 
 
OF CHEMISTRY, 
 
 347 
 
 the water produced from it is carried off through 
 the pipe ST, which fhuts by means of the flop- 
 cock r. • The whole machine is covered by the 
 lid FF, Fig. 7. made of tin painted with oil co- 
 lour, to prevent ruft. 
 
 When this machine is to be employed, the 
 middle cavity bbbb , Fig. 2. and 3. the lid GrI, 
 Fig. 4. of the interior cavity, the external cayi- 
 ty aaaa , Fig. 2. and 3. and the general lid 
 FF, Fig. 7. are all filled with pounded ice, well 
 rammed, fo that no void fpaces remain, and the 
 ice of the middle cavity is allowed to drain. 
 The machine is then opened, and the fubftance 
 fubmitted to experiment being placed in the in- 
 terior cavity, it is inflantly clofed. After wait- 
 ing till the included body is completely cooled 
 to the freezing point, and the whole melted ice 
 has drained from the middle cavity, the water 
 colle&ed in the veffel F, Fig. 1. is accurately 
 weighed. The weight of the w r ater produced 
 during the experiment is an exact meafure of 
 the caloric difengaged during the cooling of the 
 included body, as this fubltance is evidently in 
 a fimilar fituation with the one formerly men- 
 tioned as included in a hollow fphere of ice; 
 the whole caloric difengaged is flopped by the 
 ice in the middle cavity, and that ice is prefer- 
 ved from being affe&ed by any other heat by 
 means of the ice contained in the general lid. 
 Fig. 7. and in the external cavity. Experiments 
 
 of 
 
348 ELEMENTS 
 
 of this kind laft from fifteen to twenty hours ; 
 they are fometimes accelerated by covering up 
 the fubftance in the interior cavity with well 
 drained ice, which haftens its cooling. 
 
 The fubftances to be operated upon are placed 
 in the thin iron bucket. Fig. 8. the cover of 
 which has an opening fitted with a cork, into 
 which a fmall thermometer is fixed. When we 
 ufe acids, or other fluids capable of injuring the 
 metal of the inftruments, they are contained in 
 the matras. Fig. 10. which has a fimilar ther- 
 mometer in a cork fitted to its mouth, and 
 which ftands in the interior cavity upon the 
 finall cylindrical fupport RS, Fig. 10. 
 
 It is abfolutely requifite that there be no com- 
 munication between the external and middle 
 cavities of the calorimeter, otherwife the ice 
 melted by the influence of the furrounding air, 
 in the external cavity, would mix with the wa- 
 ter produced from the ice of the middle cavity, 
 which would no longer be a meafure of the ca- 
 loric loft by the fubftance fubmitted to experi- 
 ment. 
 
 When the temperature of the atmofphere is 
 only a few degrees above the freezing point, its 
 heat can hardly reach the middle cavity, being 
 arrefted by the ice of the cover. Fig 7. and of 
 the external cavity ; but, if the temperature of 
 the air be under the degree of freezing, it might 
 cool the ice contained in the middle cavity, by 
 
 caufing 
 
OF CHEMISTRY, 
 
 34 $ 
 
 caufing the ice in the external cavity to fall, in 
 the firft place, below zero (32 0 ). It is therefore 
 effential that this experiment be carried on in a 
 temperature fomewhat above freezing : Hence, 
 in time of froft, the calorimeter mud be kept 
 in an apartment carefully heated. It is likewife 
 aeceflary that the ice employed be not under 
 zero (3 2 0 ); for which purpofe it mud be pound- 
 ed, and fpread out thin for fome time, in a place 
 )f a higher temperature. 
 
 The ice of the interior cavity always retains 
 
 certain quantity of water adhering to its fur- 
 ace, which may be fuppofed to belong to the 
 efult of the experiment ; but as, at the begui- 
 ling of each experiment, the ice is already fa« 
 urated with as much water as it can contain, 
 f any of the water produced by the caloric 
 hould remain attached to the ice, it is evident, 
 hat very nearly an equal quantity of what ad- 
 lered to it before the experiment mud have 
 un down into the veffel F in its dead ; for the 
 nner furface of the ice in the middle cavity is 
 ery little changed during the experiment. 
 
 By any contrivance that could be devifed, we 
 ould not prevent the accefs of the external air 
 nto the interior cavity when the atmofphere 
 /as 9 0 or io° (52* or 54°; above zero. The 
 ir confined in the cavity being in that cafe fpe- 
 ifically heavier than the external air, efcapes 
 lownwards through the pipe x y } Fig. 3, and is 
 
 replaced 
 
$50 ELEMENTS 
 
 replaced by the warmer external air, which, 
 giving out its caloric to the ice, becomes hea- 
 vier, and finks in its turn ; thus a current of 
 air is formed through the machine, which is the 
 more rapid in proportion as the external air 
 exceeds the internal in temperature^ This cur- 
 rent of warm air mufl melt a part of the ice, 
 and injure the accuracy of the experiment : We 
 may, in a great degree, guard againft this fource 
 of error by keeping the ftop-cock u continually 
 Ihut; but it is better to operate only when the 
 temperature of the external air does not exceed 
 3°, or at mod: 4 0 , (39° to 41®); for we have 
 obferved, that, in this cafe, the melting of the 
 interior ice by the atmofpheric air is perfe&ly 
 infenfible ; fo that we may anfwer for the accu- 
 racy of our experiments upon the fpecific heat 
 of bodies to a fortieth part. 
 
 We have caufed make two of the above de- 
 fcribed machines ; one, which is intended for 
 fuch experiments as do not require the interior 
 air to be renewed, is precifely formed according 
 to the defcription here given ; the other, which 
 anfwers for experiments upon combuftion, ref- 
 piration, &c. in which frefh quantities of air are 
 indifpenfibly neceflary, differs from the former 
 in having two fmall tubes in the two lids, by 
 which a current, of atmofpheric air may be 
 blown into the interior cavity of the machine. 
 
 It 
 
OF CHEMISTRY. 
 
 35 * 
 
 It is extremely eafy, with this apparatus, to 
 ; determine the phenomena which occur in ope- 
 rations where caloric is either difengaged or ab- 
 sorbed. If we wifh, for inftance, to afcertain 
 the quantity of caloric which is difengaged from 
 i a folid body in cooling a certain number of de- 
 grees, let its temperature be raifed to 8o° (2 12 0 ); 
 it is then placed in the interior cavity ffff y 
 Fig. 2. and 3. of the calorimeter, and allowed 
 :o remain till we are certain that its tempera- 
 ture is reduced to zero (32 0 ); the water pro- 
 duced by melting the ice during its cooling is 
 ;olle£ed, and carefully weighed ; and this 
 weight, divided by the volume of the body 
 Submitted to experiment, multiplied into the 
 degrees of temperature which it had above zero 
 it the commencement of the experiment, gives 
 he proportion of what the Englifh philofophers 
 call fpecific heat. 
 
 Fluids are contained in proper veflels, whofe 
 'pecific heat has been previoully afcertained, 
 md operated upon in the machine in the fame 
 manner as directed for folids, taking care to de- 
 duct, from the quantity of water melted during 
 he experiment, the proportion which belongs 
 :o the containing velfel. 
 
 If the quantity of caloric difengaged during 
 he combination of different fubflances is to be 
 determined, thefe fubflances are to be previouf- 
 y reduced to the freezing degree by keeping 
 
 them 
 
35 * 
 
 ELEMENTS 
 
 them a fufficient time furrounded with pounded 
 ice ; the mixture is then to be made in the in- 
 ner cavity of the calorimeter, in a proper vef- 
 fel likewife reduced to zero ( 32 0 ;; and they are 
 kept inclofed till the temperature of the combi- 
 nation has returned to the fame degree : The 
 quantity of water produced is a meafure of the 
 caloric difengaged during the combin tion. 
 
 To determine the quantity of caloric difen- 
 gaged during combuflion, and during animal 
 refpiration, the combultible bodies are burnt, 
 or the animals are made to breathe in the inte- 
 rior cavity, and the water produced is carefully 
 collected. Guinea pigs, which refill: the effe&s 
 of cold extremely well, are well adapted for this 
 experiment. As the continual renewal of air is 
 abfolutely neceiTry in fuch experiments, we 
 blow frefh air into the interior cavity of the ca- 
 lorimeter by means of a pipe deflined for that 
 purpofe, and allow it to efcape through another 
 pipe of the fame kind ; and that the heat of this 
 air may not produce errors in the refults of the 
 experiments, the tube which conveys it into the 
 machine is made to pafs through pounded ice, 
 that it may be reduced to zero 13 2°) before 
 it arrives at the calorimeter. The air which 
 efcapes mud likewife be made to pafs through 
 a tube furrounded with ice, included in the in- 
 terior cavity of the machine, and the water 
 which is produced mull make a part of what is 
 
 collected, 
 

 " OF CHEMISTRY. 353 
 
 olle&ed, becaufe the caloric difengaged from 
 \is air is part of the product of the exped- 
 ient. 
 
 It is fomewhat more difficult to determine 
 he fpecific caloric contained in the different 
 ;afles, on account of their fmall degree of len- 
 ity ; for, if they are only placed in the calori- 
 neter in veifels like other fluids, the quantity 
 )f ice melted is fo fmall, that the refult of the 
 jxperiment becomes at beft very uncertain. For 
 his fpecies of experiment we have contrived to 
 'nake the air pafs through two metallic worms, 
 3r fpiral tubes ; one of thefe, through which 
 ;he air pafies, and becomes heated in its way to 
 :he calorimeter, is contained in a veflel full of 
 'boiling water, and the other, through which 
 ‘the air circulates within the calorimeter to dif- 
 engage its caloric, i§ placed in the interior ca- 
 'vity, ////, of that machine. By means of a 
 fmall thermometer placed at one end of the fe- 
 cond worm, the temperature of the air, as it 
 enters the calorimeter, is determined, and its 
 temperature in getting out of the interior cavi- 
 ty is found by another thermometer placed at 
 the other end of the worm. By this contrivance 
 we are enabled to afcertain the quantity of ice 
 melted by determinate quantities of air or gas, 
 while lofing a certain number of degrees of 
 temperature, and, confequently, to determine 
 their feveral degrees of fpecific caloric. The 
 Y v fame 
 
 j 
 
fame apparatus, with fome particular precau- 
 tions, may be employed to afcertain the quanti- 
 ty of caloric difengaged by the condenfation of 
 the vapours of different liquids. 
 
 The various experiments which may be made 
 with the calorimeter do not afford abfolute con- 
 clufions, but only give m the meafure of rela- 
 tive quantities ; we have therefore to fix a unit, 
 or ftandard point, from whence to form a feale 
 of the feverai refults. The quantity of caloric 
 neceffary to melt a pound of ice has been cho- 
 fen as this unit ; and, as it requires a pound of 
 water of the temperature of 6o° (167°) to melt 
 a pound of ice, the quantity of caloric expref- 
 fed by our unit or ftandard point is what raifes 
 a pound of water from zero f 3 2°) to 60® (167°). 
 When this unit is once determined, we have 
 only to exprefs the quantities of caloric difen- 
 gaged from different bodies by cooling a cer- 
 tain number of degrees, in analogous values : 
 The following is an eafy mode of calculation 
 for this purpofe, applied to one of our earlieft 
 experiments. 
 
 We took 7 lib . 1 1 cz, 2 grcs 36 grr. of plate- 
 iron, cut into narrow flips, and rolled up, or 
 expreffing the quantity in decimals, 7*7070319. 
 Thefe, being heated in a bath of boiling water 
 to about 78® (207.5°), were quickly introduced 
 into the interior cavity cf the calorimeter : At 
 
 the 
 
OF CHEMISTRY. 
 
 355 
 
 the end of eleven hours, when the whole quan- 
 tity of water melted from the ice had thorough- 
 ly drained off, we found that 1.109795 pounds 
 of ice were melted. Hence, the caloric diten- 
 gaged from the iron by cooling 78° (175*5°) 
 having melted 1.109795 pounds of ice, How 
 much would have been melted by cooling 6o° 
 035 0 )? This queftion gives the following ftate- 
 ment in direct proportion, 78 : i.io9795*.:6o:^= 
 0.85369. Dividing this quantity by the weight 
 of the whole iron employed, viz. 7.7070319, the 
 quotient 0.1 10770 is the quantity of ice which 
 would have been melted by one pound of iron 
 whilft cooling through 6o° (135°) of tempera- 
 ture. 
 
 Fluid fubftances, fuch as fuiphuric and nitric 
 acids, &c. are contained in a matras, PI. VI. 
 Fig. 9. having a thermometer adapted to the 
 cork, with its bulb immerfed in the liquid. The 
 matras is placed in a bath of boiling water, and 
 when, from the thermometer, we judge the li- 
 quid is raifed to a proper temperature, the ma- 
 tras is placed in the calorimeter. The calcula- 
 tion of the produ&s, to determine the fpecihc 
 caloric of thefe fluids, is made as above direc- 
 ted, taking care to deduct from the water ob- 
 tained the quantity which would have been 
 produced by the matras alone, which mult be 
 afcertained by a previous experiment. The 
 
 table 
 
3 5 6 ELEMENTS 
 
 table of the refults obtained by thefe experi- 
 ments is omitted, becaufe not yet fufficiently 
 complete, different circumftances having occa- 
 fioned the feries to be interrupted ; it is not* 
 however, loft fight of; and we are lefs or more 
 employed upon the fubjeft every winter. 
 
 i 
 
 CHAR 
 
OF CHEMISTRY/ 
 
 CHAP. IV. 
 
 Of Mechanical Operations for Divijion of Bodies . 
 
 Of Trituration , Levigation, and Pulverization* 
 
 ^'jpHESE are, properly fpeaking, only preli- 
 JL minary mechanical operations for divid- 
 ing and feparating the particles of bodies, and 
 reducing them into very fine powder. Thefe 
 operations can never reduce fubftances into their 
 primary, or elementary and ultimate particles 5 
 they do not even deftroy the aggregation of bo- 
 dies ; for every particle, after the moft accurate 
 trituration, forms a fmall whole, refembling the 
 original mafs from which it was divided. The 
 real chemical operations, on the contrary, fuch 
 as folution, deftroy the aggregation of bodies, 
 and feparate their conftituent and integrant par- 
 ticles from each other, 
 
 Brittle 
 
35 S ELEMENTS 
 
 Brittle fubftances are reduced to powder by 
 means of pefties and mortars* Thefe are of 
 brafs or iron, PI. I. Fig, i. ; of marble or gra- 
 nite, Fig 2.; of lignum vitae. Fig. 3.; of glafs, 
 fig. 4. ; of agate. Fig. 5. ; or of porcellain. 
 Fig. 6. The pefties for each of thefe are repre- 
 sented in the plate, immediately below the mor- 
 tars to which they refpeftively belong, and are 
 made of hammered iron or brafs, of wood, 
 glafs, porcellain, marble, granite, or agate, 
 according to the nature of the fubftances they 
 are intended to triturate. In every laboratory, 
 it is reauifite to have an affortment of thefe 
 utenfils, of various fizes and kinds : Thofe of 
 porcellain and glafs can only be ufed for rub- 
 bing fubftances to powder, by a dexterous ufe 
 of the peftle round the Tides of the mortar, as it 
 would be eafily broken by reiterated blows of 
 the peftle. 
 
 The bottom of mortars ought to be in the 
 form of a hollow fphere, and their Tides ihould 
 have fuch a degree of inclination as to make 
 the fubftances they contain fall back to the bot- 
 tom when the peftle is lifted, but not fo perpen- 
 dicular as to collect them too much together, 
 otherwife too large a quantity would get below 
 the peftle, and prevent its operation. For this 
 reafon, iikewife, too large a quantity of the fub- 
 (lance to be powdered ought not to be put into 
 $e mortar at one time ; and we mud from 
 
 time 
 
OF CHEMISTRY. 
 
 359 
 
 time to time get rid of the particles already re- 
 duced to powder, by means of fieves to be af- 
 terwards defcribed. 
 
 The moft ufual method of levigation is by- 
 means of a flat table ABCD, PL i. Fig. 7. of 
 porphyry, or other (tone of fimilar hardnefs, up- 
 on which the fubftance to be reduced to powder 
 is ipread, and is then bruited and rubbed by a 
 muller M, of the fame hard materials, the bot- 
 tom of which is made a fmall portion of a large 
 fphere ; and, as the muller tends continually to 
 drive the fubftances towards the Tides of the 
 table, a thin flexible knife, or fpatula of iron, 
 horn, wood, or ivory, is ufed for bringing them 
 back to the middle of the (lone. 
 
 In large works, this operation is performed 
 by means of large rollers of hard ftone, which 
 turn upon each other, either horizontally, in the 
 way of corn-mills, or by one vertical roller 
 turning upon a flat ftone. In the above opera- 
 tions, it is often requifite to moiften the fub- 
 ftances a little, to prevent the fine powder from 
 flying off. 
 
 There are many bodies which cannot be re- 
 duced to powder by any of the foregoing me- 
 thods ; fuch are fibrous fubftances, as woods ; 
 fuch as are tough and elaftic, as the horns of a- 
 nimals, elaftic gum, &c. and the malleable me- 
 tals which flatten under the peftle, inftead of 
 being reduced to powder. For reducing the 
 
 woods 
 
 t 
 
36 e ELEMENTS 
 
 woods to powder, rafps, as PI. i. Fig. 8. are em- 
 ployed ; files of a finer kind are ufed for horn, 
 and ftill finer, PI. i. Fig. 9. and 10. for metals. 
 
 Some of the metals, though not brittle e- 
 nough to powder under the peftle, are too foft 
 to be filed, as they clog the file, and prevent its 
 operation. Zinc is one of thefe, but it may be 
 powdered when hot in a heated iron mortar, or 
 it may be rendered brittle, by alloying it with 
 a fmall quantity of mercury. One or other of 
 thefe methods is ufed by fire-work makers for 
 producing a blue flame by means of zinc. Me- 
 tals may be reduced into grains, by pouring 
 them when melted into water, which ferves ve- 
 ry well when they are not wanted in fine pow- 
 der. 
 
 Fruits, potatoes, &c. of a pulpy and fibrous 
 nature may be reduced to pulp by means of the 
 grater, PI. x. Fig. 1 1. 
 
 The choice of the different fubflances of 
 which thefe inflruments are made is a matter of 
 importance ; brafs or copper are unfit for ope- 
 rations upon fubftances to be ufed as food or in 
 pharmacy ; and marble or metallic inflruments 
 mufl not be ufed for acid fubflances ; hence 
 mortars of very hard wood, and thofe of porce- 
 lain, granite, or glafs, are of great utility in 
 many operations. 
 
 S E C T. 
 
OF CHEMISTRY. 3 6r 
 
 SECT. II. 
 
 Of Sifting and Wafhing Powdered Subfiances . 
 
 None of the mechanical operations employed 
 for reducing bodies to powder is capable of pro- 
 ducing it of an equal degree of finenefs through- 
 out ; the powder obtained by the longed and 
 mod accurate trituration being dill an affem- 
 blage of particles of various fizes. The coarfer 
 of thefe are removed, fo as only to leave the 
 finer and more homogeneous particles by means 
 of fieves, PL I. Fig. 12. 13. 14. 15. of different 
 fineneffes, adapted to the particular purpofes they 
 are intended for ; all the powdered matter 
 which is larger than the intedices of the fieve 
 remains behind, and is again fubmitted to the 
 pedle, while the finer pafs through. The fieve 
 Fig. 1 2. is made of hair-cloth, or of filk gauze ; 
 and the one reprefented Fig. 13. is of parch- 
 ment pierced with round holes of a proper fize ; 
 this latter is employed in the manufacture of 
 gun-powder. When very fubtile or valuable 
 materials are to be fifted, which are eafily 
 difperfed, or when the finer parts of the powder 
 may be hurtful, a compound fieve, Fig. 15. is 
 made ufe of, which confids of the fieve ABCD, 
 with a lid EF, and receiver GH ; thefe three 
 Z z parts 
 
362 ELEMENTS 
 
 parts are reprefented as joined together for life, 
 Fig. 14. 
 
 There is a method of procuring powders of 
 an uniform finenefs, confiderably more accu- 
 rate than the fieve ; but it can only be ufed 
 with fuch fubftances as are not a&ed upon by 
 water. The powdered fubdance is mixed and 
 agitated with water, or other convenient fluid ; 
 the liquor is allowed to fettle for a few mo- 
 ments, and is then decanted off ; the coarfeft 
 powder remains at the bottom of the veflfel, and 
 the finer paffes over with the liquid. By re- 
 peated decantations in this manner, various fe- 
 diments are obtained of different degrees of 
 finenefs ; the lad fediment, or that which re- 
 mains longed fufpended in the liquor, being the 
 fined. This procefs may likewife be ufed with 
 advantage for feparating fubdances of different 
 degrees of fpecific gravity, though of the fame 
 finenefs ; this lad is chiefly employed in mining, 
 for feparating the heavier metallic ores from the 
 lighter earthy matters with which they are mix- 
 ed. 
 
 In chemical laboratories, pans and jugs of 
 glafs or earthen ware are employed for this o- 
 peration ; fometimes, for decanting the liquor 
 without aiflurbing the fediment, the glafs fy- 
 phon ABGHI, PI. II. Fig. 11. is ufed, which 
 may be fupported by means of the perforated 
 board DE, at the proper depth in the veflel 
 FG, to draw off all the liquor required into the 
 
 receiver 
 
OF CHEMISTRY. 363 
 
 receiver LM. The principles and application 
 of this ufeful inftrument are fo well known as 
 to need no explanation. 
 
 SECT. III. 
 
 Of Filtration . 
 
 A filtre is a fpecies of very fine fieve, which 
 is permeable to the particles of fluids, but 
 through which the particles of the fineft pow- 
 dered folids are incapable of pafling ; hence its 
 ufe in feparating fine powders from fufpenfion 
 in fluids. In pharmacy, very clofe and fine 
 woollen cloths are chiefly ufed for this opera- 
 tion ; thefe are commonly formed in a conical 
 fhape, PI. II. Fig. 2. which has the advantage 
 of uniting all the liquor which drains through 
 into a point A, where it may be readily collect- 
 ed in a narrow mouthed veflel. In large phar- 
 maceutical laboratories, this fiitring bag is 
 fireached upon a wooden ftand, PI. II. Fig. i. 
 
 For the purpofes of chemiftry, as it is requi- 
 fite to have the fibres perfectly clean, unfized 
 paper is fubftituted inftead of cloth or flannel ; 
 through this fubflance, no folid body, however 
 finely it be powdered, can penetrate, and fluids 
 percolate through it with the greateft readinefs. 
 
 As 
 
ELEMENTS 
 
 364 
 
 As paper breaks eafily when wet, various me- 
 thods of fupporting it are ufed according to cir- 
 cumftances. When a large quantity of fluid is 
 to be filtrated, the paper is fupported by the 
 frame of wood, PI. II. Fig. 3. ABCD, having a 
 piece of coarfe cloth ftretched over it, by means 
 of iron-hooks. This cloth mufl: be well cleaned 
 each time it is ufed, or even new cloth mufl: be 
 employed, if there is reafon to fufpe£t its being 
 impregnated with any thing which can injure 
 the fubfequent operations. In ordinary opera- 
 tions, where moderate quantities of fluid are to 
 be filtrated, different kinds of glafs funnels are 
 ufed for fupporting the paper, as reprefented 
 PI. II. Fig. 5. 6. and 7. When feveral fiitrations 
 mufl: be carried on at once, the board or fhelf 
 AB, Fig. 9. fupported upon ftands C and D, 
 and pierced with round holes, is very conveni- 
 ent for containing the funnels. 
 
 Some liquors are fo thick and clammy, as 
 not to be able to penetrate through paper with- 
 out fome previous preparation, fuch as clarifica- 
 tion by means of white of eggs, which being 
 mixed with the liquor, coagulates when brought 
 to boil, and, entangling the greater part of the 
 impurities of the liquor, rifes with them to the 
 furface in the ftate of fcum. Spiritous liquors 
 may be clarified in the fame manner by means 
 of ifmgiafs diffolved in water, which coagulates 
 
 by 
 
OF CHEMISTRY. 365 
 
 by the aftion of the alkohol without the affift- 
 ance of heat. 
 
 As mod of the acids are produced by diftil- 
 lation, and are confequently clear, we have rarely ' 
 any occafion to filtrate them ; but if, at any 
 time, concentrated acids require this operation, 
 it is impoflible to employ paper, which would 
 be corroded and deftroyed by the acid. For 
 this purpofe, pounded glafs, or rather quartz or 
 rock-criftal, broke in pieces and grofsly pow- 
 dered, anfwers very well ; a few of the larger 
 pieces are put in the neck of the funnel ; thefe 
 are covered with the fmaller pieces, the finer 
 powder is placed over all, and the acid is poured 
 on at top. For the ordinary purpofes of focie- 
 ty, river-water is frequently filtrated by means 
 of clean waihed fand, to feparate its impuri- 
 ties. 
 
 SECT. IV. 
 
 Of Decantation . 
 
 This operation is often fubftituted inftead of 
 filtration for feparating folid particles which are 
 diffufed through liquors. Thefe are allowed to 
 fettle in conical veffels, ABCDE, PL II. Fig. 10. 
 the diffufed matters gradually fubflde, and the 
 
 clear 
 
S S6 ELEMENTS 
 
 clear fluid is gently poured off*. If the fediment 
 be extremely light, and apt to mix again with 
 the fluid by the flighted motion, the fyphon, 
 Fig. ii. is ufed, inftead of decantation, for 
 drawing off the clear fluid. 
 
 In experiments, where the weight of the pre- 
 cipitate muff be rigoroufly afcertained, decan- 
 tation is preferable to filtration, providing the 
 precipitate be feveral times wafhed in a confider- 
 able proportion of w^ater. The weight of the 
 precipitate may indeed be afcertained, by care- 
 fully weighing the filtre before and after the o- 
 peration ; but, when the quantity of precipitate 
 is fmall, the different proportions of moilture 
 retained by the paper, in a greater or leffer de- 
 gree of exficcation, may prove a material fource 
 of error, which ought carefully to be guarded 
 againft. 
 
 CHAP. 
 
O l 1 ' CHEMISTRY. 367 
 
 CHAP. V. 
 
 > 
 
 Of Chemical Means for fcparating the Particles of 
 Bodies from each other , without Decompofition , 
 and for uniting them again . 
 
 "I" have already fhown that there are two me- 
 3k thods of dividing the particles of bodies, the 
 mechanical and chemical . The former only fe- 
 parates a folid mafs into a great number of 
 fmaller maffes ; and for thele purpofes various 
 fpecies of forces are employed, according to cir- 
 cumftances, fuch as the ftrength of man or of 
 animals, the weight of water applied through 
 the means of hydraulic engines, the expanfive 
 power of fleam, the force of the wind, &c. By 
 all thefe mechanical powers, we can never re- 
 duce fubflances into powder beyond a certain 
 degree of finenefs ; and the fmalleft particle 
 produced in this way, though it feems very 
 minute to our organs, is ftill in fad a moun- 
 tain, when compared with the ultimate elemen- 
 tary particles of the pulverized fubftance. 
 
 The chemical agents, on the contrary, divide 
 I bodies into their primitive particles. If, for in- 
 ftance, a neutral fait be aded upon by thefe, it 
 ! is divided, as far as is poflible, without ceafing 
 to be a neutral fait. In this Chapter, I mean to 
 
 give 
 
3 68 ELEMENTS 
 
 give examples of this kind of divifion of bodies, 
 to which I fhall add fome account of the rela- 
 tive operations. 
 
 SECT. I. 
 
 Of the Solution of Salts . 
 
 In chemical language, the terms of folution 
 and diffolution have long been confounded, and 
 have very improperly been indiscriminately em- 
 ployed for exprefling both the divifion of the 
 particles of a fait in a fluid, fuch as water, and 
 the divifion of a metal in an acid. A few re- 
 flexions upon the effeXs of thefe two opera- 
 tions will Suffice to fhow that they ought not to 
 be confounded together. In the folution of 
 falts, the faline particles are only Separated from 
 each other, whilft neither the fait nor the water 
 are at all decompofed ; we are able to recover 
 both the one and the other in the fame quantity 
 as before the operation. The fame thing takes 
 place in the folution of refins in alkohol. Du- 
 ring metallic diffolutions, on the contrary, a 
 decomposition, either of the acid, or of the wa- 
 ter which dilutes it, always takes place ; the 
 metal combines with oxygen, and is changed 
 into an oxyd, and a gafleous fubftance is difen- 
 gaged ; fo that in reality none of the fubftan- 
 
 ces 
 
OF CHEMISTRY. 369 
 
 ces employed remain, after the operation, in the 
 fame date they were in before. This article is 
 entirely confined to the confideration of folia- 
 tion. 
 
 To underdand properly what takes place du- 
 ring the folution of falts, it is neceflary to know, 
 that, in molt of thefe operations, two diftind 
 effeds are complicated together, viz. folution by 
 water, and folution by caloric ; and, as the ex- 
 planation of mod of the phenomena of folution 
 depends upon the diftindion of thefe two cir- 
 cumdances, I fhall enlarge a little upon their 
 nature. 
 
 Nitrat of potafh, ufually called nitre or fait- 
 petre, contains very little water of cridailiza- 
 tion, perhaps even none at all ; yet this fait li- 
 quifies in a degree of heat very little fuperior to 
 that of boiling water. This liquifadion cannot 
 therefore be produced by means of the water of 
 cridailization,but inconfequenceof the fait being 
 very fufible in its nature, and from its palling from 
 the folid to the liquid date of aggregation, when 
 but a little raifed above the temperature of boil- 
 ing water. All falts are in this manner fufcep- 
 tible of being liquified by caloric, but in higher 
 or lower degrees of temperature. Some of 
 thefe, as the acetites of potafh and foda, liquify 
 with a very moderate heat, whild others, as fui- 
 phat of potafli, lime, &c. require the dronged 
 fires we are capable of producing. This liqui- 
 3 A Ta-.ipn 
 
37 ° 
 
 ELEMENTS 
 
 faftion of falts by caloric produces exaftly the 
 fame phenomena with the melting of ice ; it is 
 accomplifhed in each fait by a determinate de- 
 gree of heat, which remains invariably the fame 
 during the whole time of the liquifa&ion. Ca- 
 loric is employed, and becomes fixed during the 
 melting of the fait, and is, on the contrary, dif- 
 engaged when the fait coagulates. Thefe are 
 general phenomena which univerfally occur du- 
 ring the paffage of every fpecies of fubflance 
 from the folid to the fluid flate of aggregation, 
 and from fluid to folid. 
 
 Thefe phenomena arifing from folution by 
 caloric are always lefs or more conjoined with 
 thofe which take place during folutions in water* 
 We cannot pour water upon a fait, on purpofe 
 to diflblve it, without employing a compound 
 folvent, both water and caloric ; hence we may 
 diftinguifh feveral different cafes of folution, ac- 
 cording to the nature and mode of exigence of 
 each fait. If, for inftance, a fait be difficultly 
 foluble in water, and readily fo by caloric, it 
 evidently follows, that this fait will be difficult- 
 ly ^foluble in cold water, and confiderably in 
 hot water ^ fuch is nitrat of potafh, and more 
 efpecially oxygenated muriat of potafh. If an- 
 other fait be little foluble both in vrater and ca- 
 loric, the difference of its folubility in cold and 
 warm water will be very inconfiderabie ; ful- 
 phat of lime is of this kind. From thefe confi- 
 
 derations. 
 
OF CHEMISTRY. 
 
 37 * 
 
 derations, it follows, that there is a neceffary 
 relation between the following circumftances ; 
 the folubility of a fait in cold water, its folubiiity 
 in boiling water, and the degree of temperature 
 at which the fame fait liquifies by caloric, unaffift- 
 ed by water ; and that the difference of folubility 
 in hot and cold water is fo much greater in pro- 
 portion to its ready foiution in caloric, or in 
 proportion to its fulceptibility of liquifying in a 
 low degree of temperature. 
 
 The above is a general view of foiution ; but, 
 for want of particular fadts, and fufficiently ex- 
 adt experiments, it is Hill nothing more than an 
 approximation towards a particular theory. I he 
 means of compleating this part of chemical fci- 
 ence is extremely fimple ; we have only to af- 
 certain how much of each fait is diffolved by a 
 certain quantity of water at different degrees of 
 temperature; and as, by the experiments pu- 
 biifhed by Mr de la Place and me, the quantity 
 of caloric contained in a pound of water at each 
 degree of the thermometer is accurately known, 
 it will be very eafy to determine, by fimple ex- 
 periments, the proportion of water and caloric 
 required for foiution by each fait, what quantity 
 of caloric is abforbed by each at the moment of 
 iiquifadtion, and how much is difengaged at the 
 moment of criftallization. hence the reafon 
 why falts are more rapidly foluble in hot than 
 *n cold water is perfectly evident. In all folu- 
 
 tions 
 
37 * 
 
 ELEMENTS 
 
 tions of falts caloric is employed ; when tha^ is 
 furnifhed intermediately from the furrounding 
 b( ches. it can only arrive flowly to the fait \ 
 whe,e s this is greatly accelerated wheabbe-re- 
 quiiite caloric exifls ready combined with the 
 water of folution. 
 
 In general, the fpecific gravity of water is 
 augmented by holding falts in folution ; but 
 there are fome exceptions to the rule. Some 
 time hence, the quantities of radical, of oxygen, 
 and of bafe, which conftitute each neutral fait, 
 the quantity of water and caloric neceffary for 
 folution, the increafed fpecific gravity commu- 
 nicated to water, and tire figure of the elemen- 
 tary particles of the criflals, will all be accurate- 
 ly known. From thefe all the circumflances 
 and phenomena of criftallization will be ex- 
 plained, and by thefe means this part of chernif- 
 try will be compleated. Mr Seguin has formed 
 the plan of a thorough inveftigation of this 
 kind, which he is extremely capable of execu- 
 ting. 
 
 The folution of falts in water requires no par- 
 ticular apparatus ; fmall glafs phials of different 
 fizes, PI. II. Fig, 1 6* and 17. pans of eartherri 
 ware, A, Fig, 1. and 2. long-necked matraffes. 
 Fig 14. and pans or bafons of copper or of fil- 
 ver, Fig. 13. and 15. anfwer very well for thefe 
 operations. 
 
 S E G To 
 
OF CHEMISTRY. 
 
 373 
 
 SECT. II. 
 
 Of Lixiviation . 
 
 This is an operation ufed in chemiltry and 
 manufactures for feparating fubftances which 
 are folubie in water from fuch as are infoluble. 
 The large vat or tub, Pi. II. Fig. 1 2. having a 
 hole D near its bottom, containing a wooden 
 fpiget and folfet or metallic Hop-cock DE, is 
 generally ufed for this purpofe. A thin Hratum 
 of draw is placed at the bottom of the tub ; 
 over this, the fubftance to be lixiviated is laid 
 and covered by a cloth, then hot or cold water, 
 according to the degree of folubility of the fa- 
 line matter, is poured on. When the water is 
 fuppofed to have diffolved all the faline parts, it 
 is let off by the Hop-cock ; and, as fome of the 
 water charged with fait necefiarily adheres to 
 the draw and infoluble matters, feveral frefh 
 quantities of water are poured on. The Hraw 
 ferves to fecure a proper paflage for the water, 
 and may be compared to the flraws or glafs 
 rods ufed in filtrating, to keep the paper from 
 touching the fides of the funnel. The cloth 
 which is laid over the matters under lixiviation 
 prevents the water from making a hollow in 
 
 thefe 
 
374 
 
 ELEMENTS 
 
 thefe fubftances where it is poured on, through 
 which it might efcape without a&ing upon the 
 whole mafs. 
 
 This operation is lefs or more imitated in che- 
 mical experiments ; but as in thefe, efpecially 
 with analytical views, greater exa&neis is re- 
 quired, particular precautions mult be employ- 
 ed, fo as not to leave any faline or foluble part 
 in the reiiduum. More water mult be employ- 
 ed than in ordinary lixiviations, and the fub- 
 ftances ought to be previoully ftirred up in the 
 water before the clear liquor is drawn off, other- 
 wife the whole mafs might not be equally lixi- 
 viated, and lome parts might even efcape alto- 
 gether from the a&ion of the water. We muff 
 likewife employ frelh portions of water in con- 
 fiderable quantity, until it comes off entirely 
 free from fait, which we may afcertain by means 
 of the hydrometer formerly deicribed. 
 
 In experiments with fmall quantities, this 
 operation is conveniently performed in jugs or 
 matraffes of glafs, and by filtrating the liquor 
 through paper in a glafs funnel. When the 
 fubftance is in larger quantity, it may be lixivi- 
 ated in a kettle of boiling water, and filtrated 
 through paper fupported by cloth in the wood- 
 en frame, PI. II. Fig. 3. and 4. ; and in opera- 
 tions in the large way, the tub already mention- 
 ed muff be ufed. 
 
 S E Cl 
 
OF CHEMISTRY. 
 
 373 
 
 SECT. III. 
 
 Of Evaporation . 
 
 This operation is ufed for feparating two fub- 
 fiances from each other, of which one at lead 
 muft be fluid, and whofe degrees of volatility 
 Jare confiderably different. By this means we 
 obtain a fait, which has been diflblved in water, 
 in its concrete form ; the water, by heating, be- 
 comes combined with caloric, which renders it 
 volatile, while the particles of the fait being 
 brought nearer to each other, and within the 
 fphere of their mutual attra&ion, unite into the 
 folid date. 
 
 As it was long thought that the air had great 
 influence upon the quantity of fluid evaporated, 
 it will be proper to point out the errors which 
 this opinion has produced. There certainly is 
 a conftant flow evaporation from fluids expofed 
 to the free air ; and, though this fpecies of eva- 
 poration may be confidered in fome degree as a 
 folution in air, yet caloric has confiderable in- 
 fluence in producing it, as is evident from the 
 refrigeration which always accompanies this pro- 
 cefs ; hence we may confider this gradual eva- 
 poration as a compound folution made partly ia 
 
 air* 
 
ELEMENTS 
 
 air, and partly in caloric. But the evaporation 
 which takes place from a fluid kept continually 
 boiling, is quite different in its nature, and in it 
 the evaporation produced by the aftion of the 
 air is exceedingly inconfiderable in comparifon 
 with that which is occafioned by caloric. This 
 latter fpecies may be termed vaporization rather 
 than evaporation . This procefs is not accelera- 
 ted in proportion to the extent of evaporating 
 furface, but in proportion to the quantities of 
 caloric which combine with the fluid. Too free 
 a current of cold air is often hurtful to this pro- 
 cefs, as it tends to carry off* caloric from the wa- 
 ter, and confequently retards its converfion into 
 vapour. Hence there is no inconvenience pro- 
 duced by covering, in a certain degree, the vef- 
 fels in which liquids are evaporated by continual 
 boiling, provided the covering body be of fuch 
 a nature as does not ftrongly draw off* the calo- 
 ric, or, to ufe an expreflion of Dr Franklin’s, 
 provided it be a bad conductor of heat. In this 
 cafe, the vapours efcape through fuch opening 
 as is left, and at lead as much is evaporated, 
 frequently more than when free accefs is allow- 
 ed to the external air. 
 
 x\s during evaporation the fluid carried off by 
 caloric is entirely loff, being facrificed for the 
 fake of the fixed fubftances with which it was 
 combined, this procefs is only employed where 
 the fluid is of fmall value, as water, for inftance. 
 
 But, 
 
OF CHEMISTRY. 
 
 377 
 
 But, when the fluid is of more confequence, we 
 have recourfe to difhilation, in which procefs 
 we preferve both the fixed fubftance and the vo- 
 latile fluid. The veflels employed for evapora- 
 tion are bafons or pans of copper, filver, or 
 lead, PL II. Fig. 13. and 15. or capluies of 
 glafs, porcellain, or If one ware, Pi II. A, Fig. 1. 
 and 2. PI. III. Fig. 3 and 4. The belt utenfils 
 for this purpofe are made of the bottoms of glafs 
 retorts and matrafles, as their equ 1 thinnefs ren- 
 ders them more fit than any other kind of glafs 
 veffel for bearing a brifk fire and fudden alte- 
 rations of heat and cold without breaking. 
 
 As the method of cutting thefe glafs veflels is 
 no where defcribed in books, I fhali here give a 
 defcription of it, that they may be made by 
 chemifts for themfelves out of fpoiled retorts, 
 matrafles, and recipients, at a much cheaper 
 rate than any which can be procured from glaft 
 manufacturers. The inftrument, FI. III. Fig. c. 
 confiding of an iron ring AC, fixed to the rod 
 AB, having a wooden handle D, is employed as 
 follows : Make the ring red hot in the fire, and 
 put it upon the matrafs G, Fig. 6. which is to 
 be cut ; when the glafs is fufiiciently heated, 
 throw on a little cold water, and it will gene- 
 rally break exactly at the circular line heated 
 by the ring. 
 
 Small flafks or phials of thin glafs are exceed- 
 ing good veflels for evaporating finall quantities 
 3 B of 
 
373 ELEMENTS 
 
 of fluid ; they are very cheap, and (land the fire 
 remarkably. One or more of thefe may be 
 placed upon a fecond grate above the furnace, 
 PI. III. Fig. 2% where they will only experience 
 a gentle heat. By this means a great number 
 of experiments may be carried on at one time. 
 A glals retort, placed in a fand-bath, and co- 
 vered with a dome of baked earth, Pi. III. Fig. i. 
 anfwers pretty well for evaporations ; but in this 
 way it is always confiderably flower, and is even 
 liable to accidents ; as thefand heats unequally, 
 and the glafs cannot dilate in the fame unequal 
 manner, the retort is very liable to break. 
 Sometimes the fand ferves exaftly the office of 
 the iron ring formerly mentioned ; for, if a 
 flag le drop of vapour, condenfed into liquid, 
 happens to fall upon the heated part of the vef- 
 fel, it breaks circularly at that place. When a 
 very interne fire is neceflary, earthen crucibles 
 may be ufed ; but we generally ufe the word 
 evaporation to exprefs what is produced by the 
 teronerature of boiling water, or not much 
 higher. 
 
 SECT. 
 
OF CHEMISTRY. 
 
 379 
 
 SECT. IV. 
 
 Of Cri/lallization. 
 
 In this procefs the integrant parts of a folid 
 body, feparated from each other by the inter- 
 vention of a fluid, are made to exert the mutual 
 attraction of aggregation, fo as to coalefce and 
 reproduce a folid mafs. When the particles of 
 a body are only feparated by caloric, and the 
 fubftance is thereby retained in the liquid (late, 
 all that is neceflary for making it criflallize, is to 
 remove a part of the caloric which is lodged 
 between its particles, or, in other words, to cool 
 it. If this refrigeration be How, and the body 
 be at the fame time left at reft, its particles ai- 
 fume a regular arrangement, and criflaliization, 
 properly fo called, takes place ; but, if the re- 
 frigeration is made rapidly, or if the liquor be 
 agitated at the moment of its paflage to the con- 
 crete (late, the criflaliization is irregular and 
 confufed. 
 
 The fame phenomena occur with watery folu- 
 tions, or rather in thole made partly in water, 
 and partly by caloric. So long as there remains 
 a (efficiency of water and caloric to keep the 
 particles of the body afunder beyond the fphere 
 
 of 
 
ELEMENTS 
 
 380 
 
 of their mutual attraction, the fait remains in 
 the fluid ftate ; but, whenever either caloric or 
 water is not prefent in fufficient quantity, and 
 the attraction of the particles for each other be- 
 comes fuperior to the power which keeps them 
 afunder, the fait recovers its concrete form, and 
 the criftals produced are the more regular in 
 proportion as the evaporation has been flower 
 and more tranquilly performed. 
 
 All the phenomena we formerly mentioned 
 as taking place during the folution of falts, oc- 
 cur in a contrary fenfe during their criftalliza- 
 tion. Caloric is difengaged at the inftant of 
 their a flaming the folid ftate, which furniihes 
 an additional proof of fait being held in folu- 
 tion by the compound aClion of water and ca- 
 loric. Hence, to caufe falts to criftallize which 
 readily liquify by means of caloric, it is not fuf- 
 ftcient to carry off the water which held them 
 in folution, but the caloric united to them mull 
 iikewife be removed. Nitrat of potafh, oxyge- 
 nated muriat of potafh, alum, fulphat of foda, 
 &c. are examples of this circumftance, as, to 
 make thefe falts criftallize, refrigeration muft be 
 added to evaporation. Such falts, on the con- 
 trary, asirequire little caloric for being kept in 
 folution, and which, from that circumftance, 
 are nearly equally foluble in cold and warm 
 water, are criftallizabie by Amply carrying off 
 the water which holds them in folution, and 
 
 even 
 
OF CHEMISTRY. 381 
 
 even recover their folid ftate in boiling water 5 
 fuch are fulphat of lime, muriat of potafh and 
 of foda, and feveral others. 
 
 The art of refining faltpetre depends upon 
 thefe properties of falts, and upon their different 
 degrees of folubility in hot and cold water. This 
 fait, as produced in the manufactories by the 
 firft operation, is compofed of many different 
 falts ; fome are deliquefdent, and not fufceptible 
 of being criftaliized, fuch as the nitrat and mu* 
 riat of lime ; others are almoft equally foluble 
 in hot and cold water, as the muriats of potafh 
 and of foda ; and, laftly, the faltpetre, or nitrat 
 of potafh, is greatly more foluble in hot than it 
 is in cold water. The operation is begun, by 
 pouring upon this mixture of falts as much wa* 
 ter as will hold even the leaft foluble, the mu« 
 riats of foda and of potafh, in folution; fo long 
 as it is hot, this quantity readily diffoives all the 
 faltpetre, but, upon cooling, the greater part of 
 this fait criftallizes, leaving about a fixth part 
 remaining diffolved, and mixed with the nitrat 
 of lime and the two muriats. The nitre obtain- 
 ed by this procefs is ftiii fomewhat impregnated 
 with other falts, becaufe it has been criftaliized 
 from water in which thele abound : It is com- 
 pletely purified from thefe by a lecond folution 
 in a fmail quantity of boiling water, and lecond 
 criftallization. The water remaining after thefe 
 criftallizations of nitre is ftill loaded with a mix- 
 ture 
 
382 ELEMENTS 
 
 ture of faltpetre, and other falts j by farther eva- 
 poration, crude faltpetre, or rough-petre, as the 
 workmen call it, is procured from it, and this 
 Is purified by two frefh folutions and criftalli- 
 zations. 
 
 The deliquefcent earthy falts which do not 
 contain the nitric acid are rejected in this ma- 
 nufacture ; but thofe which confift of that acid 
 neutralized by an earthy bafe are diflolved in 
 water, the earth is precipitated by means of pot- 
 afh, and allowed to fubfide ; the clear liquor is 
 then decanted, evaporated, and allowed to crif- 
 tallize. The above management for refining 
 faltpetre may ferve as a general rule for Sepa- 
 rating falts from each other which happen to 
 be mixed together. The nature of each muft 
 be confidered, the proportion in which each dif- 
 folves in given quantities of water, and the dif- 
 ferent Solubility of each in hot and cold water. 
 If to thefe we add the property which fome falts 
 poflefs, of being Soluble in alkohol, or in a mix- 
 ture of alkohol and water, we have many re- 
 sources for Separating Salts from each other by 
 means of criftallization, though it muft be al- 
 lowed that it is extremely difficult to render this 
 Separation perfectly complete. 
 
 The vefiels uled for criftallization are pans 
 of earthen ware, A, PL 11 . Fig. 1. and 2. and 
 large flat dirties, PL III. Fig. 7. When a Saline 
 Solution is to be expofed to a flow evaporation 
 
 in 
 
OF CHEMISTRY. 
 
 383 
 
 in the heat of the atmofphere, with free accefs 
 of air, vefiels of fome depth, PI. III. Fig. 3. 
 mud be employed, that there may be a confi- 
 derable body of liquid ; by this means the crif- 
 tals produced are of confiderable fize, and re- 
 markably regular in their figure. 
 
 Every fpecies of fait cridallizes in a peculiar 
 form, and even each fait varies in the form of 
 its cridals according to circumdances, which 
 take place during cridallization. We mud not 
 from thence conclude that the faline particles of 
 each fpecies are indeterminate in their figures : 
 The primative particles of all bodies, efpecially 
 of falts, are perfe&ly condant in their fpecific 
 forms ; but the cridals which form in our ex- 
 periments are compofed of congeries of minute 
 particles, which, though perfe&ly equal in fize 
 and fhape, may aflume very diflimilar arrange- 
 ments, and confequently produce a vad variety 
 of regular forms, which have not the fmalled 
 apparent refemblance to each other, nor to the 
 original cridal. This fubject has been very ably 
 treated by the Abbe Haliy, in feveral memoirs 
 prefented to the Academy, and in his work up- 
 on the dructure of cridals : It is only neceflary 
 to extend generally to the clafs of fairs the prin- 
 ciples he has particularly applied to fome crifta- 
 lized dones. 
 
 SECT. 
 
§84 
 
 ELEMENTS 
 
 SECT. V. 
 
 Of Simple D filiation. 
 
 As diftillation has two diftinCt objects to ac- 
 complifti, it is divilible into fimple and com- 
 pound ; and, in this fefrion, I mean to confine 
 xnyfelf entirely to the former. When two bo- 
 dies, of which one is more volatile than the 
 other, or has more affinity to caloric, are iub- 
 mitted to diftillation, our intention is to fepa- 
 rate them from each other : The more volatile 
 fubftance affumes the form of gas, and is after- 
 wards concerned by refrigeration in proper vef- 
 fels. In this cafe diftillation, like evaporation, 
 becomes a fpecies of mechanical operation, 
 which feparates two fubftances from each other 
 without decompofmg or altering the nature of 
 either. In evaporation, our only objeft is to 
 preferve the fixed body, without paying any re- 
 gard to the volatile matter ; whereas, in diftil- 
 lation, our principal attention is generally paid 
 to the volatile fubftance, unlefs when we intend 
 to preferve both the one and the other. Hence, 
 fimple diftillation is nothing more than evapo- 
 ration produced in clofe veffels. 
 
 1 he mod fimple diftilling veflel is a fpecies 
 of bottle or matrafs. A, PI, III. Fig. 8. which has 
 
 been 
 
OF CHEMISTRY. 385 
 
 been bent from its original form BC to BD, 
 and which is then called a retort ; when ufed, 
 it is placed either in a reverberatory furnace, 
 PJ. XIII. Fig. 2. or in a fand bath under a dome 
 of baked earth, PI. III. Fig. 1. To receive and 
 condenfe the produ&s, we adapt a recipient, E, 
 PI. III. Fig. 9. which is luted to the retort. 
 Sometimes, more efpecially in pharmaceutical 
 operations, the glafs or done ware cucurbit, A, 
 with its capital B, PL III. Fig. 12. or the glafs 
 alembic and capital, Fig. 13. of one piece, is 
 employed. This latter is managed by means of 
 a tubulated opening T, fitted with a ground 
 ftopper of criftal ; the capital, both of the cu- 
 curbit and alembic, has a furrow or trench, rr, 
 intended for conveying the condenfed liquor 
 into the beak RS, by which it runs out. As, 
 in aimod all diftillations, expanfive vapours are 
 produced, which might built the vefiels employ- 
 ed, we are under the necefllty of having a finall 
 hole, T, Fig. 9. in the balloon or recipient, 
 through which thefe may find vent ; hence, in 
 this way of diddling, all the products which are 
 permanently aeriform are entirely lod, and even 
 fuch as difficultly lofe that date have not fufficient 
 fpace to condenfe in the S'allqOjP : This appara- 
 tus is not, therefore, proper fm experiments of 
 inveftigation, and can only be admitted in the 
 ordinary operations of the laboratory or in 
 pharmacy. In the article appropriated for com- 
 3 C pound 
 
 V 
 
386 ELEMENTS 
 
 pound diftillation, I fhall explain the various 
 methods which have been contrived for prefer- 
 ving the whole produ&s from bodies in this 
 procefs. 
 
 As glafs or earthen veffels are very brittle, 
 and do not readily bear fudden alterations of 
 heat and cold, every well regulated laboratory 
 ought to have one or more alembics of metal 
 for diftilling water, fpiritous liquors, eflential 
 oils, &c. This apparatus confifts of a cucurbit 
 and capital of tinned copper or brafs, PI. III. 
 Fig. 15. and 16. which, when judged proper, 
 maybe placed in the water bath, D, Fig. 17. 
 In diftillations, efpecially of fpiritous liquors, 
 the capital mult be furnifhed with a refrigetory, 
 SS, Fig. 16. kept continually filled with cold 
 water ; when the water becomes heated, it is 
 let off by the flop-cock, R, and renewed with a 
 frefn fuppiy of cold water. As the fluid diftil- 
 led is converted into gas by means of caloric 
 furnifhed by the fire of the furnace, it is evi- 
 dent that it could not condenfe, and, confe- 
 quently, that no diftillation, properly fpeaking, 
 could take place, unlefs it is made to depofit in 
 the capital all the caloric it received in the cu- 
 curbit ; with this view, the Tides of the capital 
 mud always be preferved at a lower tempera- 
 ture than is necefiary for keeping the diftiiling 
 fubftance in the flate of gas, and the water in 
 the refrigetory is intended for this purpofe. 
 
 Water 
 
OF CHEMISTRY. 387 
 
 Water Is converted into gas by the temperature 
 of 8o° (212 0 ), alkohol by 67° (182 75°), ether 
 by 32 0 (i°4°); hence thefe fu; fiances cannot 
 be diflilled, or, rather, they will fly off in the 
 Hate of gas, unlefs the temperature of the re- 
 frigetory be kept under thefe refpe&ive de- 
 grees. 
 
 In the diflillation of fpiritous, and other ex- 
 panfive liquors, the above defcribed refrigetory 
 is not fufficient for condenfing all the vapours 
 which arife ; in this cafe, therefore, inftead of 
 receiving the diflilled liquor immediately from 
 the beak, TU, of the capital into a recipient, 
 a worm is interpofed between them. This in- 
 flrument is reprefented PI. III. Fig. 18. contain- 
 ed in a worm tub of tinned copper, it confifts 
 of a metallic tube bent into a confiderable num- 
 ber of (piral revolutions. The veffel which con- 
 tains the worm is kept full of cold water, which 
 is renewed as it grows warm. This contrivance 
 is employed in all diflilleries of fpirits, without 
 the intervention of a capital and refrigetory, 
 properly fo called. The one reprefented in the 
 plate is furnifhed with two worms, one of them 
 being particularly appropriated to did illations 
 of odoriferous fubflances. 
 
 In fome fimple diflillations it is necelfary to 
 interpofe an adopter between the retort and re- 
 ceiver, as fhov/n PI. ill. Fig. 11. This may 
 
 fervo 
 
3 38 ELEMENTS 
 
 ferv' f wo different purpofes, either to feparate 
 two produ&s of different degrees of volatility, 
 or to remove the receiver to a greater diftance 
 from the furnace, that it may be lefs heated. 
 But thefe, and feveral other more complicated 
 inftruments of ancient contrivance, are far from 
 producing the accuracy requifite in modem 
 chemiftrv, as will be readily perceived when l 
 come to treat of compound diftillatioa. 
 
 SEC T. VI. 
 Of Sublimation, 
 
 This term is applied to the diftillation of fub* 
 fiances which condenfe in a concrete or folid 
 form, fuc'i as the fublimation of fulphur, and of 
 muriat of ammoniac, or fal ammoniac. Thefe 
 operations may be conveniently performed in 
 the ordinary diftilling veffels already deferibed, 
 though, in the fublimation of fulphur, a fpe- 
 cies of veffels, named Alludels, have been ufu- 
 ally employed. Thefe are veffels of flone or 
 porcelain ware, which adjuft to each other over 
 a cucurbit containing the fulphur to be fubliin- 
 ed. One of the befi: fubliming veffels, for fub- 
 flances which are not very volatile, is a flafk, 
 
 or 
 
OF CHEMISTRY. 389; 
 
 or phial of glafs, funk about two thirds into a 
 fand bath ; but in this way we are apt to lofe a 
 part of the products. When thefe are wifhed 
 to be entirely preferved, we mud have recourfe 
 to the pneumato-chemical diftilling apparatus, 
 to be defcribed in the following chapter. 
 
 CHAP. 
 
ELEMENTS 
 
 29° 
 
 CHAP. VI. 
 
 O -» * r '* 'i 
 
 Of Pneumato * chemical Dijlillaiions , Metallic Dijfo* 
 lutions , fome other operations which require 
 
 very complicated injlruments . 
 
 SECT. I. 
 
 0/" Compound and Pneumato- chemical Dijlillatiom . 
 
 I N the preceding chapter, I have only treated 
 of diftillation as a fimple operation, by which 
 two fubftances, differing in degrees of volatility, 
 may be feparated from each other ; but diftilla- 
 tion often a&ually decompofes the fubftances 
 fubmitted to its a&ion, and becomes one of the 
 moft complicated operations in chemiftry. In 
 every diftillation, the fubftance diftilled mull: be 
 brought to the ftate of gas, in the cucurbit or 
 retort, by combination with caloric : In fimple 
 diftillation, this caloric is given out in the re- 
 frigeratory or in the worm, and the fubftance 
 again recovers its liquid or folid form, but the 
 fubftances fubmitted to compound diftillation 
 
 are 
 
OF CHEMISTRY. 
 
 39 * 
 
 are abfolutely decompounded ; one part, as for 
 inftance the charcoal they contain, remains fix- 
 ed in the retort, and all the reft of the elements 
 are reduced to gaffes of different kinds. Some 
 of thefe are fufceptible of being condenfed, and 
 of recovering their folid or liquid forms, whilft 
 others are permanently aeriform ; one part of 
 thefe are abforbable by water, fome by the al- 
 kalies, and others are not fufceptible of being 
 abi'orbed at all. An ordinary diftilhng appara- 
 tus, fuch as has been defcribed in the preceding 
 chapter, is quite inefficient for retaining or for 
 feparating thefe diverfified products, and we are 
 obliged to have recourfe, for this purpofe, to 
 methods of a more complicated nature. 
 
 The apparatus I am about to defcribe is cal- 
 culated for the moft complicated diftillations, 
 and may be fimplified according to circumftan- 
 ces. It confifts of a tubulated glafs retort A, 
 PI. IV. Fig. i. having its beak fitted to a tubu- 
 lated balloon or recipient BC ; to the upper ori- 
 fice D of the balloon a bent tube DE/g* is ad- 
 jufted, which, at its other extremity g, is plun- 
 ged into the liquor contained in the bottle L, 
 with three necks xxx. Three other fimilar 
 bottles are connected with this firft one, by 
 means of three fimilar bent tubes difpofed in 
 the fame manner ; and the fartheft neck of the 
 laft bottle is connected with a jar in a pneuma- 
 to- chemical apparatus, by means of a bent 
 
 tube. 
 
392 
 
 ELEMENTS 
 
 tube *. A determinate weight of diftilled water 
 is ufually put into the firft bottle, and the other 
 three have each a folution of cauftic potafh in 
 water. The weight of all thefe bottles, and of 
 the water and alkaline folution they contain, 
 muft be accurately afcertained. Every thing 
 being thus difpofed, the jun&ures between the re- 
 tort and recipient, and of the tube D of the lat- 
 ter, muft be luted with fat lute, covered over 
 with flips of linen, fpread with lime and white 
 of egg ; all the other junctures are to be fecu- 
 red by a lute made of wax and rofm melted to- 
 gether. } 
 
 When all thefe difpofitions are completed, 
 and when, by means of heat applied to the re- 
 tort A, the fubftance it contains becomes de- 
 compofed, it is evident that the lead volatile 
 products muft condenfe or fublime in the beak 
 or neck of the retort itfelf, where moft of the 
 concrete fubftances will fix themfelves. The 
 more volatile fubftances, as the lighter oils, am- 
 moniac, and feveral others, will condenfe in the 
 recipient GC, whilft the gaflfes, which are not 
 fufceptible of condenfation by cold, will pafs on 
 by the tubes, and boil up through the liquors 
 in the feveral bottles. Such as are abforbable 
 
 by 
 
 * The reprefentation of this apparatus, PI. IV. 
 Pig. i. will convey a much better idea of its difpoli- 
 ticn than can poffibly be given by the moll laboured 
 defcripticn. — E. 
 
OF CHEMISTRY. 
 
 393 
 
 by water will remain in the firft bottle, and 
 thofe which cauftic alkali can abforb will re- 
 main in the others ; whilft fuch gaffes as are 
 not fufceptible of abforption, either by water or 
 alkalies, will efcape by the tube RM, at the end 
 of which they may be received into jars in a 
 pneumato-chemical apparatus. The charcoal 
 and fixed earth, &c. which form the fubftance 
 or refiduum, anciently called caput mortuum , re- 
 main behind in the retort. 
 
 In this manner of operating, we have always 
 a very material proof of the accuracy of the a- 
 nalyfis, as the whole weights of the produ&s 
 taken together, after the procefs is finifhed, 
 muff be exactly equal to the "weight of the ori- 
 ginal fubftance fubmitted to diftillation. Hence, 
 for inftance, if we have operated upon eight 
 ounces of ftarch or gum arabic, the weight of 
 the charry refiduum in the retort, together with 
 that of ali the products gathered in its neck and 
 the balloon, and of ail the gas received into the 
 jars by the tube RM added to the additional 
 weight acquired by the bottles, muft, when ta- 
 ken together, be exaQly eight ounces. If the 
 product be lefs or more, it proceeds from er- 
 ror, and the experiment muft be repeated until 
 a fatisfactory refult be procured, which ought 
 not to differ more than fix or eight grains in the 
 pound from the weight of the fubftance fubmit- 
 ted to experiment. 
 
 3 D 
 
 In 
 
394 
 
 ELEMENTS 
 
 In experiments of this kind, I for a long time 
 met with an almoft infurmountable difficulty, 
 which muft at laft have obliged me to defifl al- 
 together, but for a very fimpie method of avoid- 
 ing it, pointed out to me by Mr Hafienfratz. 
 The fmalleft diminution in the heat of the fur- 
 nace, and many other circumftances infeparable 
 from this kind of experiments, caufe frequent 
 reabforptions of gas ; the water in the ciftern of 
 the pneumato chemical apparatus rufhes into the 
 laft bottle through the tube RM, the fame cir- 
 cumftance happens from one bottle into ano- 
 ther, and the fluid is often forced even into the 
 recipient C. This accident is prevented by u- 
 flng bottles having three necks, as reprefented 
 in the plate, into one of which, in each bottle, 
 a capillary glafs-tube St, st, st, st, is adapted, fo 
 as to have its lower extremity t immerfed in 
 the liquor. If any abforption takes place, either 
 in the retort, or in any of the bottles, a fuffi- 
 cient quantity of external air enters, by means 
 of thefe tubes, to fill up the void ; and we get 
 rid of the inconvenience at the price of having 
 a fmall mixture of common air with the pro- 
 duds of the experiment, which is thereby pre- 
 vented from failing altogether. Though thefe 
 tubes admit the external air, they cannot per- 
 mit any of the gafleous fubftances to efcape, as 
 they are always (hut below by the water of the 
 bottles. 
 
 It 
 
OF CHEMISTRY. 395 
 
 It is evident that, in the courfe of experi- 
 ments with this apparatus, the liquor of the bot- 
 tles muft rife in thefe tubes in proportion to the 
 prelfure fuftained by the gas or air contained in 
 the bottles ; and this prelfure is determined by 
 the height and gravity of the column of fluid 
 contained in all the fubfequent bottles. If we 
 fuppofe that each bottle contains three inches 
 of fluid, and that there are three inches of wa- 
 ter in the cillern of the connected apparatus a- 
 bove the orifice of the tube RM, and allowing 
 the gravity of the fluids to be only equal to that 
 of water, it follows that the air in the firffc bot- 
 tle mull fuftain a prelfure equal to twelve inch- 
 es of water ; the water mull therefore rife 
 twelve inches in the tube S, connected with the 
 firlt bottle, nine inches in that belonging to the 
 fecond, fix inches in the third, and three in the 
 lalt ; wherefore thefe tubes mull be made 
 lomewhat more than twelve, nine, fix, and three 
 inches long refpectively, allowance being made 
 for ofcillatory motions, which often take place 
 in the liquids. It is fometimes neceflary to in- 
 troduce a fimilar tube between the retort and 
 recipient ; and, as the tube is not immerfed in 
 fluid at its lower extremity, until foine has col- 
 lected in the progrefs of the dilf illation, its up- 
 per end muft be fliut at firlt with a little lute, fo 
 as to be opened according to neceflity, or after 
 
 there 
 
396 ELEMENTS 
 
 there is fufficient liquid in the recipient to fe- 
 cure its lower extremity. 
 
 This apparatus cannot be ufed in very accu- 
 rate experiments, when»the fubftances intended 
 to be operated upon have a very rapid action 
 upon each other, or when one of them can 
 only be introduced in fmall fucceflive portions, 
 as in fuch as produce violent eflervefcence when 
 mixed together. In fuch cafes, we employ a 
 tubulated retort A, PI. VII Fig. i. into which 
 one of the fubitances is introduced, preferring 
 always the folid body, if any fuch is to be treat- 
 ed, we then lute to the opening of the retort a 
 bent tube BCD A, terminating at its upper ex- 
 tremity B in a funnel, and at its other end A in 
 a capillary opening. The fluid material of the 
 experiment is poured into the retort by means 
 of this funnel, which mult be made of fuch a 
 length, from B to C, that the column of liquid 
 introduced may counterbalance the refiftance 
 produced by the liquors contained in all the 
 bottles, PI. IV. Fig. i. 
 
 Thofe who have not been accuftomed to ufe 
 the above defcribed diddling apparatus may 
 perhaps be ftartled at the great number of open- 
 ings which require luting, and the time necef- 
 fary for making all the previous preparations in 
 experiments of this kind. It is very true that, 
 if we take into account all the neceflary weigh- 
 ings of materials and products, both before and 
 
 after 
 
OF CHEMISTRY, 
 
 397 
 
 after the experiments, thefe preparatory and 
 fucceeding fteps require much more time and 
 attention than the experiment itfelf. But, when 
 the experiment fucceeds properly, we are well 
 rewarded for all the time and trouble bellowed, 
 as by one precefs carried on in this accurate 
 manner much more juft and extenfive know- 
 ledge is acquired of the nature of the vege- 
 table or animal fubftance thus fubmitted to 
 inveftigation, than by many weeks afliduous la* 
 bour in the ordinary method of proceeding. 
 
 When in w r ant of bottles with three orifices, 
 thofe with two may be ufed ; it is even poflible 
 to introduce all the three tubes at one opening, 
 fo as to employ ordinary wide-mouthed bottles, 
 provided the opening be fufficiently large. In 
 this cafe we muft carefully fit the bottles with 
 corks very accurately cut, and boiled in a mix- 
 ture of oil, wax, 2nd turpentine. Thefe corks 
 are pierced with the neceftary holes for receiv- 
 ing the tubes by means of a round file, as in 
 PL IV. Fig. 8. 
 
 SECT. 
 
393 ELEMENTS 
 
 SECT. II. 
 
 Of Metallic DiJJolutions. 
 
 I have already pointed out the difference be- 
 tween folution of falts in water and metallic 
 diffolutions. The former requires no particular 
 veffels, whereas the latter requires very compli- 
 cated veffels .of late invention, that we may not 
 lofe any of the produ&s of the experiment, and 
 may thereby procure truly conclufive refults of 
 the phenomena which occur. The metals, in 
 general, diffolve in acids with effervefcence, 
 which is only a motion excited in the folvent by 
 the difengagement of a great number of bubbles 
 of air or aeriform fluid, which proceed from the 
 furface of the metal, and break at the furface of 
 the liquid. 
 
 Mr Cavendifh and Dr Prieftley were the firlt 
 inventors of a proper apparatus for collefting 
 thefe elaftic fluids. That of Dr Prieftley is ex- 
 tremely Ample, and confifts of a bottle A, 
 Pi. VII. Fig. 2 . with its cork B, through which 
 paffes the bent glafs tube BC, which is engaged 
 under a jar filled with water in the pneumato- 
 chemical apparatus, or Amply in a bafon full of 
 water. The metal is firft introduced into the 
 
 bottle, 
 
OF CHEMISTRY. 
 
 399 
 
 bottle, the acid is then poured over it, and the 
 bottle is inftantly clofed with its cork and tube, 
 as reprefented in the plate. But this apparatus 
 has its inconveniencies. When the acid is 
 much concentrated, or the metal much divided, 
 the effervefcence begins before we have time to 
 cork the bottle properly, and fome gas efcapesj 
 by which we are prevented from afcertaining 
 the quantity difengaged with rigorous exa&nefs. 
 In the next place, when we are obliged to em- 
 ploy heat, or when heat is produced by the pro- 
 cefs, a part of the acid diftills, and mixes with 
 the water of the pneumato-chemical apparatus, 
 by which means we are deceived in our calcu- 
 lation of the quantity of acid decompofed. Be- 
 fides thefe, the water in the cittern of the appa- 
 ratus abforbs all the gas produced which is fuf- 
 ceptiblc of abforption, and renders it impoflible 
 
 to collect thefe without lofs. 
 
 « 
 
 To remedy thefe inconveniencies, I at firtt 
 ufed a bottle with two necks, PI. VII. Fig. 3. 
 into one of which the glafs funnel BC is luted 
 fo as to prevent any air efcaping ; a glafs rod 
 DE is fitted with emery to the funnel, fo as to 
 ferve the purpofe of a ftopper. When it is 
 ufed, the matter to be dittolved is firtt intro- 
 duced into the bottle, and the acid is then per- 
 mitted to pafs in as (lowly as we pleafe, by rai- 
 fing the glafs rod gently as often as is neceflary 
 until faturation is produced. 
 
 Another 
 
400 ELEMENTS 
 
 Another method has been fince employed, 
 which ferves the fame purpofe, and is preferable 
 to the Iaft defcribed in fome inftances. This 
 confifts in adapting to one of the mouths of the 
 bottle A, PI. VII. Fig. 4. a bent tube DEFG, 
 having a capillary opening at D, and ending in 
 a funnel at G. This tube is lecurely luted to 
 the mouth C of the bottle. When any liquid 
 is poured into the funnel, it falls down to F ; 
 and, if a fufficient quantity be added, it pailes 
 by the curvature E, and falls flowly into the 
 bottle, fo long as frefn liquor is fupplied at the 
 funnel. The liquor can never be forced out of 
 the tube, and no gas can efcape through it, be- 
 caufe the weight of the liquid ferves the pur- 
 pofe of an accurate cork. 
 
 To prevent any diftillation of acid, efpecially 
 in diffolutions accompanied with heat, this tube 
 is adapted to the retort A, PI. VII. Fig. 1. and 
 a fmall tubulated recipient, M, is applied, in 
 which any liquor which may diftill is condenfed. 
 On purpofe to feparate any gas that is abforb- 
 able by water, we add the double necked bot- 
 tle L, half filled with a folution of cauflic pot- 
 afh ; the alkali abforbs any carbonic acid gas, 
 and ufuaily only one or two other gaffes pafs 
 into the jar of the conne&ed pneumato-chemi- 
 cal apparatus through the tube NO. In the 
 firfl: chapter of this third part we have dire&ed 
 how thefe are to be feparated and examined. 
 
 If 
 
 
OF CHEMISTRY. 
 
 401 
 
 If one bottle of alkaline folution be not thought 
 fufficient, two, three, or more, may be added. 
 
 SECT. III. 
 
 Apparatus neceffary in Experiments upon Vinous 
 and Putrefactive Fermentations . 
 
 For thefe operations a peculiar apparatus, 
 efpecially intended for this kind of experiment, 
 is requifite. lhe one I am about to defcribe is 
 finally adopted, as the beft calculated for the 
 purpofe, after numerous corrections and im- 
 provements. It confifls of a large matrafs, 
 
 PL X. fig. 1 . holding about twelve pints, with 
 a cap of brafs ab> ftrongly cemented to its 
 mouth, and into which is fcrewed a bent tube 
 ed , furniflied with a flop-cock e . To this tube 
 is joined the glafs recipient B, having three 
 openings, one of which communicates with the 
 bottle C, placed below it. To the poflerioi 
 opening of this recipient is fitted a glafs tube 
 g/6/, cemented at g and i to collets of brafs, 
 and intended to contain a very deliquefcent 
 concrete neutral fait, fuch as nitrat or muriat of 
 lime, acetire of potafh, &c. This tube commu-* 
 ideates with two bottles D and E, filled to .v 
 and y with a folution of cauftic potafh. 
 
 3 E All 
 
402 
 
 ELEMENTS 
 
 All the parts of this machine are joined to- 
 gether by accurate fcrews, and the touching 
 parts have greafed leather interpofed, to prevent 
 any padage of air. Each piece is likewife fur- 
 nifhed with two ftop-cpcks, by which its two 
 extremities may be clofed, fo that we can weigh 
 each feparately at any period of the operation. 
 
 The fermentable matter, fuch as fugar, with 
 a proper quantity of yeaft, and diluted with wa- 
 ter, is put into the matrafs. Sometimes, when 
 the fermentation is too rapid, a confidence 
 quantity of froth is produced, which not only 
 fills the neck of the matrafs, but paffes into the 
 recipient, and from thence runs down into the 
 bottle C. On purpofe to colled this fcum and 
 mud, and to prevent it from reaching the tube 
 filled with deliquefcent falts, the recipient and 
 conne&ed bottle are made of confiderable capa- 
 city. 
 
 In the vinous fermentation, only carbonic 
 acid gas is difengaged, carrying with it a fmali 
 proportion of water in folution. A great part 
 of this water is depofited in paffing through the 
 tube g h i, which is filled with a deliquefcent 
 fait in grofs powder, and the quantity is afcer- 
 tained by the augmentation of the weight of the 
 fait. The carbonic acid gas bubbles up through 
 the alkaline folution in the bottle D, to which 
 ‘it is conveyed by the tube khn. Any finall 
 portion which may nof be abforbed by this 
 
 firft 
 
OF CHEMISTRY. 
 
 403 
 
 firft bottle is fecured by the folution in the fe- 
 cond bottle E, fo that nothing, in general, 
 paffes into the jar F, except the common air 
 contained in the vefifels at the commencement 
 of the experiment. 
 
 The fame apparatus anfwers extremely well 
 for experiments upon the putrefadive fermen- 
 tation ; but, in this cafe* a confiderable quan- 
 tity of hydrogen gas is difengaged through the 
 tube qrstu , by which it is conveyed into the 
 jar F ; and, as this difengagement is very rapid, 
 efpecially in fuinmer, the jar muft be frequently 
 changed. Thefe putrefadive fermentations re- 
 quire conftant attendance from the above cir- 
 cumftance, whereas the vinous fermentation 
 hardly needs any. By means of this apparatus 
 we can ascertain, with great precifion, the 
 weights of the fubflances fubmitted to fermen- 
 tation, arid of the liquid and aeriform produds 
 which are difengaged. What has been already 
 faid in Part I. Chap. XIII. upon the produds 
 of the vinous fermentation, may be confulted* 
 
 SECT, 
 
404 ELEMENTS 
 
 SECT. IV. 
 
 Apparatus for the Decompofition of Water* 
 
 Having already given an account, in the firft 
 part of this work, of the experiments relative 
 to the decompofition of water, I fhall avoid any 
 unneceffary repetitions, and only give a few 
 fummary obfervations upon the fubjeft in this 
 fe&ion. The principal fubftances which have 
 the power of decompofing water are iron and 
 charcoal ; for which purpofe, they require to 
 be made red hot, otherwife the water is only re- 
 duced into vapours, and condenfes afterwards 
 by refrigeration, without fuftaining the fmalleft 
 alteration. In a red heat, on the contrary, iron 
 cr charcoal carry off the oxygen from its union 
 with hydrogen ; in the firft cafe, black oxyd of 
 iron is produced, and the hydrogen is difenga- 
 ged pure in form of gas ; in the other cafe, 
 carbonic acid gas is formed, which difengages, 
 mixed with the hydrogen gas ; and this latter is 
 commonly carbonated, or holds charcoal in fo- 
 lution. 
 
 A mufket barrel, without its breach pin, an- 
 fwers exceedingly well for the decompofition of 
 water, by means of iron, and one fhould be 
 
 chofen 
 
OF CHEMISTRY, 
 
 405 
 
 chofen of confiderable length, and pretty ftrong. 
 When too fhort, fo as to run the rife of heating 
 the lute too much, a tube of copper is to be 
 ftrongly foldered to one end. The barrel is 
 placed in a long furnace, ( DEF, PL VII. Fig. 
 a i . fo as to have a few degrees of inclination 
 from E to F 5 a glafs retort A, is luted to the 
 upper extremity E, which contains water, and 
 is placed upon the furnace VVXX. The lower 
 extremity F is luted to a worm SS, which is 
 conne&ed with the tubulated bottle H, in which 
 any water diftilled without decompofition, du- 
 ring the operation, colle£ls, and the difengaged 
 gas is carried by the tube KK to jars in a pneu- 
 mato- chemical apparatus. Inftead of the retort 
 a funnel may be employed, having its lower 
 part fhut by a flop- cock, through which the 
 water is allowed to drop gradually into the gun- 
 barrel. Immediately upon getting into contaft 
 with the heated part of the iron, the water is 
 converted into fleam, and the experiment pro- 
 ceeds in the lame manner as if it were furnifh- 
 ed in vapours from the retort. 
 
 In the experiment made by Mr Meufnier and 
 me before a committee of the Academy, we 
 ufed every precaution to obtain the greatefl 
 poflible precilion in the refult of our experi- 
 ment, having even exhaufled all the veffels em- 
 ployed before we began, fo that the hydrogen 
 gas obtained might be free from any mixture 
 
 of 
 
%o 6 ELEMENTS 
 
 of azotic gas. The refults of that experiment 
 will hereafter be given at large in a particular 
 memoir. 
 
 In numerous experiments, we are obliged to 
 ufe tubes of glafs, porcelain, or copper, inftead 
 of gun-barrels ; but glafs has the difadvantage 
 of being eafily melted and flattened, if the heat 
 be in the fmalleft degree raifed too high ; and 
 porcelain is moftly full of fmall minute pores, 
 through which the gas efcapes, efpecially when 
 comprefled by a column of water. For thefe 
 reafons I procured a tube of brafs, which Mr 
 de la Briche got caft and bored out of the folid 
 for me at Strafburg, under his own infpe&ion. 
 This tube is extremely convenient for decom- 
 pofing alkohol, which refolves into charcoal, 
 carbonic acid gas, and hydrogen gas ; it may 
 likewife be ufed with the fame advantage for 
 decompoflng water by means of charcoal, and 
 in a great number of experiments of this na- 
 ture. 
 
 CHAR 
 
OF CHEMISTRY. 
 
 407 
 
 CHAP. VIL 
 
 Of the Compofition and Application of Lutes * 
 
 rp H E neceffity of properly fecuring the 
 JL jun&ures of chemical veffels to prevent 
 the efcape of any of the products of experiments, 
 mud be fufficiently apparent ; for this purpofe 
 lutes are employed, which ought to be of iuch a 
 nature as to be equally impenetrable to the molt 
 fubtile fubftances, as glafs itfelf, through which 
 only caloric can efcape. 
 
 This firfl object of lutes is very w^ell accom- 
 plifhed by bees wax, melted with about an 
 eighth part of turpentine. This lute is very 
 eafily managed, flicks very clofely to glafs, and 
 is very difficultly penetrable; it may be rendered 
 more confiflent, and lefs or more hard or pliable, 
 by adding different kinds of relinous matters. 
 Though this fpecies of lute anfwers extremely 
 well for retaining gaffes and vapours, there are 
 many chemical experiments which produce con- 
 fiderable heat, by which this lute becomes li- 
 quified, and confequently the expanfive vapours 
 mult very readily force through and efcape. 
 
 For 
 
4o8 ELEMENTS 
 
 For fuch cafes, the following fat lute is the 
 beft hitherto difcovered, though not without its 
 difadvantages, which fhall be pointed out. 
 Take very pure and dry unbaked clay, reduced 
 to a very fine powder, put this into a brafs mor- 
 tar, and beat it for feveral hours with a heavy 
 iron peftle, dropping in flowly fome boiled lint- 
 feed oil ; this is oil which has been oxygenated, 
 and has acquired a drying quality, by being 
 boiled with litharge. This lute is more tena- 
 cious, and applies better, if amber varnifh be u- 
 fed inflead of the above oil. To make this var- 
 nifli, melt fome yellow amber in an iron laddie, 
 by which operation it lofes a part of its fuccinic 
 acid, and effential oil, and mix it with lintfeed 
 oil. Though the lute prepared with this var- 
 nifh is better than that made with boiled oil, 
 yet, as its additional expence is hardly com- 
 penfated by its fuperior quality, it is feldom 
 ufed. 
 
 The above fat lute is capable of fuftaining a 
 very violent degree of heat, is impenetrable by 
 acids and fpiritous liquors, and adheres exceed- 
 ingly well to metals, (tone ware, or glafs, provi- 
 ding they have been previoufly rendered per- 
 fe&iy dry. But if, unfortunately, any of the 
 liquor in the courfe of an experiment gets 
 through, either between the glafs and the lute, 
 or between the layers of the lute itfelf, fo as to 
 moiften the part, it is extremely difficult to clofe 
 
 the 
 
OF CHEMISTR Y. 
 
 409 
 
 the opening. This is the chief inconvenience 
 which attends the ufe of fat lute, and perhaps 
 the only one it is fubjed to. As it is apt to fof- 
 ten by heat, we muft furround all the junctures 
 with flips of wet bladder applied over the luting, 
 and fixed on by pack-thread tied round both 
 above and below the joint ; the bladder, and 
 confequently the lute below, muft be farther 
 fecured by a number of turns of pack-thread all 
 over it. By thefe precautions, we are free from 
 every danger of accident; and the junctures 
 fecured in this manner may be conftdered, in 
 experiments, as hermetically fealed. 
 
 It frequently happens that the figure of the 
 junctures prevents the application of ligatures, 
 which is the cafe with the three- necked bottles 
 formerly defcribed ; and it even requires great 
 addrefs to apply the twine without fhaking the 
 apparatus ; fo that, where a number of junc- 
 tures require luting, we are apt to difplace fe*» 
 veral while fecuring one. In thefe cafes, we 
 may fubftitute flips of linen, fpread with white 
 of egg and lime mixed together, inftead of the 
 wet bladder. Thefe are applied while ftill 
 moift, and very fpeedily dry and acquire confi- 
 derable hardnefsc Strong glue diifolved in wa- 
 ter may anfwer inftead of white of egg. Thefe 
 fillets are ufefully applied likewife over junc- 
 tures luted together with wax and roan. 
 
 3 F Before 
 
4io 
 
 ELEMENTS 
 
 Before applying a lute, all the junctures of 
 the veffels mud be accurately and firmly fitted 
 to each other, fo as not to admit of being mo- 
 ved. If the beak of a retort is to be luted to 
 the neck of a recipient, they ought to fit pretty 
 accurately ; otherwife we mud fix them, by in- 
 troducing fhort pieces of foft wood or of cork. 
 If the difproportion between the two be very 
 confiderable, we mufl employ a cork which fits 
 the neck of the recipient, having a circular hole 
 of proper dimenfions to admit the beak of the 
 retort. The fame precaution is neceffary in 
 adapting bent tubes to the necks of bottles 
 in the apparatus reprefented PI. IV. Fig. t. 
 and others of a fimilar nature. Each mouth of 
 each bottle mufl be fitted with a cork, having a 
 hole made with a round file of a proper fize for 
 containing the tube. And, when one mouth is 
 intended to admit two or more tubes, which 
 frequently happens when we have not a fuffi- 
 cient number of bottles with two or three 
 necks, we mufl ufe a cork with two or three 
 holes, PI. IV. Fig. 8. 
 
 When the whole apparatus is thus folidly 
 joined, fo that no part can play upon another, 
 we begin to lute. Ihe lute is foftened by 
 kneading and rolling it between the fingers, 
 .with the abidance of heat, if neceffary. It is 
 rolled into little cylindrical pieces, and applied 
 to the junctures, taking great care to make it 
 
 apply 
 
 
OF CHEMISTRY. 
 
 4ir 
 
 apply clofe, and adhere firmly, in every part ; a 
 fecond roll is applied over the firft, fo as to pafs 
 it on each fide, and fo on till each jun&ure be 
 fufficiently covered ; after this, the flips of blad- 
 der, or of linen, as above dire&ed, mull be 
 carefully applied over all. Though this opera- 
 tion may appear extremely fimple, yet it requires 
 peculiar delicacy and management ; great care 
 muft be taken not to dilturb one jundure whillt 
 luting another, and more efpecially when ap- 
 plying the fillets and ligatures. 
 
 Before beginning any experiment, the clofe- 
 nefs of the luting ought always to be previoufly 
 tried, either by flightly heating the retort A, 
 PI. IV. Fig. i, or by blowing in a little air by 
 fome of the perpendicular tubes S s s s ; the al- 
 teration of preflure caufes a change in the level 
 of the liquid in thefe tubes. If the apparatus 
 be accurately luted, this alteration of level will 
 be permanent ; whereas, if there be the final left 
 opening in any of the jundures, the liquid will 
 very foon recover its former level. It mud al- 
 ways be remembered, that the whole fuccefs of 
 experiments in modern chemiftry depends upon 
 the exadnefs of this operation, which therefore 
 requires the utmofc patience, and mofl attentive 
 accuracy. 
 
 It would be of infinite fervice to enable cue- 
 mills, efpecially thofe who are engaged in pneu- 
 matic proceifes, to difpehfe with the ufe of lutes, 
 
 or 
 
ELEMENTS 
 
 412 
 
 or at leafl to diminifh the number neceffary in 
 complicated inftruments. I once thought of 
 having my apparatus conftrudted fo as to unite 
 in all its parts by fitting with emery, in the w r ay 
 of bottles with criftal hoppers ; but the execu- 
 tion of this plan was extremely difficult. I have 
 fince thought it preferable to fubftitute columns 
 of a few lines of mercury in place of lutes, 
 and have got an apparatus conftructed upon 
 this principle, which appears capable of very 
 convenient application in a great number of 
 circumftances. 
 
 It confifts of a double necked bottle A, PI. 
 XII. Fig. 12. ; the interior neck be communi- 
 cates with the infide of the bottle, and the ex- 
 terior neck or rim de leaves an interval between 
 the two necks, forming a deep gutter intended 
 to contain the mercury. The cap or lid of 
 giafs B enters this gutter, and is properly fitted 
 to it, having notches in its lower edge for the 
 paffage of the tubes which convey the gas. 
 Thefe tubes, inftead of entering direftly into 
 the bottles as in the ordinary apparatus, have a 
 double bend for making them enter the gutter, 
 as reprefented in Fig. 13. and for making them 
 fit the notches of the cap B j they rife again 
 from the gutter to enter the infide of the bottle 
 over the border cf the inner mouth. When the 
 tubes are aifpofed in their proper places, and 
 the cap firmly fitted on, the gutter is filled with 
 
 mer« 
 
OF CHEMISTRY. 
 
 413 
 
 mercury, by which means the bottle is com- 
 pletely excluded from any communication, ex- 
 cepting through the tubes. This apparatus may 
 be very convenient in many operations in which 
 the fubftances employed have no a&ion upon 
 Mercury. PI. XII. Fig. 14. reprefents an ap- 
 paratus upon this principle properly fitted toge- 
 ther. 
 
 Mr Seguin, r to whofe a&ive and intelligent 
 affiftance I have been very frequently much in- 
 debted, has befpoken for me, at the glafs-hou- 
 fes, fome retorts hermetically united to their 
 recipients, by which luting will be altogether 
 unneceffary. 
 
 CHAP. 
 
ELEMENTS 
 
 414 
 
 CHAP. VIII. 
 
 Of Operations upon Combuftion and Deflagration* 
 
 SECT. I. 
 
 Of Combujlion in general . 
 
 C OMBUSTION, according to what has 
 been already faid in the Firft Part of this 
 Work, is the decompofition of oxygen gas pro- 
 duced by a combuftible body, 'lhe oxygen 
 which forms the bafe of this ga$ is abforbed by, 
 and enters into, combination with the burning 
 body, while the caloric and light are fet free. 
 Every combuftion, therefore, neceflarily fuppo- 
 fes oxygenation ; whereas, on the contrary, e- 
 very oxygenation dees not neceflarily imply 
 concomitant combuftion ; becaufe combuftion, 
 properly fo called, cannot take place without 
 difengagement of caloric and light. Before 
 combuftion can take place, it is neceffary that 
 the bafe of oxygen gas fliould have greater affi- 
 nity to the combuftible body than it has to ca- 
 loric ; 
 
OF CHEMISTRY. 
 
 4*S 
 
 lorlc ; and this ele&ive attraction, to ufe Berg- 
 man’s expreflion, can only take place at a cer- 
 tain degree of temperature, which is different 
 for each combuftible fubftance ; hence the ne- 
 ceffity of giving a firfl motion or beginning to 
 every combuftion by the approach of a heated 
 body. This neceflity of heating any body we 
 mean to burn depends upon certain confidera- 
 tions, which have not hitherto been attended to 
 by any natural philofopher, for which reafon I 
 fhall enlarge a little upon the fubjeCt in this 
 place. 
 
 Nature is at prefent in a ftate of equilibrium, 
 which cannot have been attained until all the 
 fpontaneous combuftions or oxygenations pof- 
 fibie in the ordinary degrees of temperature had 
 taken place. Hence, no new combuftions or 
 oxygenations can happen without deftroying 
 this equilibrium, and raifing the combuftible 
 fubftances to a fuperior degree of temperature. 
 To illuftrate this abftraCl: view of the matter by 
 example : Let us fuppofe the ufual temperature 
 of the earth a little changed, and that it is raifed 
 only to the degree of boiling water ; it is evi- 
 dent, that, in this cafe, phofphorus, which is 
 combuftible in a confiderably lower degree of 
 temperature, would no longer exift in nature in 
 its pure and fimple ftate, but would always be 
 procured in its acid or oxygenated ftate, and its 
 radical would become one of the fubftances un- 
 known 
 
ELEMENTS 
 
 41 6 
 
 known to chemiftry. By gradually increafing 
 the temperature of the earth the fame circum- 
 ftance would fucceffively happen to all the bo- 
 dies capable of combuftion ; and, at laft, every 
 poffible combuftion having taken place, there 
 would no longer exift any combuftible body 
 whatever, as every fubftance fufceptible of that 
 operation would be oxygenated, and confe- 
 quently incombuftible. 
 
 There cannot therefore exift, fo far as relates 
 to us, any combuftible body, except fuch as are 
 incombuftible in the ordinary temperatures of 
 the earth ; or, what is the fame thing, in other 
 words, that it is effential to the nature of every 
 combuftible body not to poilefs the property of 
 combuftion, unlefs heated, or raifed to the degree 
 of temperature at which its combuftion natural- 
 ly takes place. When this degree is once pro- 
 duced, combuftion commences, and the caloric 
 which is difengaged by the decompofition of 
 the oxygen gas keeps up the temperature ne- 
 ceffary for continuing combuftion. When this 
 is not the cafe, that is, when the difengaged ca- 
 loric is inefficient for keeping up the neceftary 
 temperature, the combuftion ceafes : This cir- 
 cumftance is exprefied in common language 
 by faying, that a body burns ill, or with diffi- 
 culty. 
 
 Although combuftion pofleffes fome circum- 
 ftances in common with diftillation, efpecially 
 
 with 
 
OF CHEMISTRY. 
 
 417 
 
 with the compound kind of that operation, they 
 differ in a very material point. In diftillation 
 there is a reparation of one part of the elements 
 of the fubflance from each other, and a combi- 
 nation of thefe, in a new order, occafioned by 
 the affinities which take place in the increafed 
 temperature produced during diftillation : This 
 likewife happens in combuftion, but with this 
 farther circumftance, that a new element, not 
 originally in the body, is brought into action ; 
 oxygen is added to the fubflance fubmitted to 
 the operation, and caloric is difengaged. 
 
 The neceffity of employing oxygen in the 
 ftate of gas in all experiments with combuftion, 
 and the rigorous determination of the quanti- 
 ties employed, render this kind of operations 
 peculiarly troublefome. As almofl all the pro- 
 ducts of combuftion are difengaged in the ftate 
 of gas, it is (till more difficult to retain them 
 than even thofe furnifhed during compound di- 
 ftillation ; hence this precaution was entirely 
 neglected by the ancient chemifts ; and this fee 
 of experiments exclufively belong to modern 
 chemiftry. 
 
 Having thus pointed out, in a general way, 
 the objeCls to be had in view in experiments 
 upon combuftion, I proceed, in the following 
 feClions of this chapter, to deferibe the different 
 inftruments 1 have ufed with this view. The fol- 
 lowing arrangement is formed, not upon the 
 3 G nature 
 
4*8 ELEMENTS 
 
 / 
 
 nature of the combuftible bodies, but upon that 
 of the inftruments neceflary for combuftion. 
 
 SEC T. II. 
 
 Of the Combuftion of Phofphorus. 
 
 i .. ;, 4 /. ,1 
 
 In thefe combuftions we begin by filling a jar, 
 capable at lead of holding fix pints, with oxy- 
 gen gas in the water apparatus, PL V. Fig. i. ; 
 when it is perfe&ly full, fo that the gas begins 
 to flow out below, the jar. A, is carried to the 
 mercury apparatus, PL IV. Fig. 3. We then 
 dry the furface of the mercury, both within and 
 without the jar, by means of blotting-paper, ta- 
 king care to keep the paper for fome time en- 
 tirely immerfed in the mercury before it is in- 
 troduced under the jar, left we let in any com- 
 mon air, which flicks very obflinately to the 
 furface of the paper. The body to be fubmit- 
 ted to combuftion, being firft very accurately 
 weighed in nice fcales, is placed in a fmall flat 
 fhallow difh, D, of iron or porcelain ; this is 
 covered by the larger cup P, which ferves the 
 office of a diving bell, and the whole is pafled 
 through the mercury into the jar, after which 
 the larger cup is retired. The difficulty of paf- 
 fing the materials of combuftion in this manner 
 
 through 
 
OF CHEMISTRY. 
 
 419 
 
 through the mercury may be avoided by raifing 
 one of the fides of the jar. A, for a moment, 
 and flipping in the little cup, D, with the com- 
 buftible body as quickly as poflible. In this 
 manner of operating, a fmall quantity of com- 
 mon air gets into the jar, but it is fo very in- 
 confiderable as not to injure either the progrefs 
 or accuracy of the experiment in any fenfible 
 degree. 
 
 When the cup, D, is introduced under the 
 jar, we fuck out a part of the oxygen gas, fo as 
 to raife the mercury to EF, as formerly direded. 
 Part I. Chap. V. otherwife, when the combuf- 
 tible body is fet on fire, the gas becoming di- 
 lated would be in part forced out, and we fhould 
 no longer be able to make any accurate calcu- 
 lation of the quantities before and after the ex- 
 periment. A very convenient mode of draw- 
 ing out the air is by means of an air-pump fy- 
 Tinge adapted to the fyphon, GHI, by which 
 the mercury may be railed to any degree under 
 twenty- eight inches. Very inflammable bodies, 
 as phofphorus, are fet on fire by means of the 
 crooked iron wire, MN, PI. IV. Fig. 16. made 
 red hot, and paflfed quickly through the mercu- 
 ry. Such as are lefs ealily fet on fire have a 
 fmall portion of tinder, upon which a minute 
 particle of phofphorus is fixed, laid upon them 
 before ufing the red hot iron. 
 
 In 
 
ELEMENTS 
 
 420 
 
 In the firft moment of combuftion the air, 
 being heated, rarifies, and the mercury defcends; 
 but when, as in combuftions of phofphorus and 
 iron, no elaftic fluid is formed, abforption be- 
 comes prefently very fenfible, and the mercury 
 rifes high into the jar. Great attention muft 
 be ufed not to burn too large a quantity of any 
 fubftance in a given quantity of gas, otherwife, 
 towards the end of the experiment, the cup 
 would approach fo near the top of the jar as to 
 endanger breaking it by the great heat produ- 
 ced, and the fudden refrigeration from the cold 
 mercury. For the methods of meafuring the 
 volume of the gafles, and for correcting the 
 meafures according to the heighth of the baro- 
 meter and thermometer, &c. fee Chap. II. Se£t. 
 V. and VI. of this part. 
 
 The above procefs anfwers very well for 
 burning all the concrete fubftances, and even 
 for the fixed oils : Thefe laft are burnt in lamps 
 under the jar, and are readily fet on fire by 
 means of tinder, phofphorus, and hot iron. But 
 it is dangerous for fubftances fufceptible of eva- 
 porating in a moderate heat, fuch as ether, al- 
 kohol, and the effential oils ; thefe fubftances 
 difloive in confiderable quantity in oxygen gas; 
 and, when fet on fire, a dangerous and fudden 
 explofion takes place, which carries up the jar 
 to a great height, and dafhes it in a thoufand 
 pieces. From two fuch explofions fome of the 
 
 members 
 
OF CHEMISTRY. 
 
 421 
 
 
 members of the Academy and myfelf efcaped 
 very narrowly. Befides, though this manner of 
 operating is fufficient for determining pretty ac- 
 curately the quantity of oxygen gas abforbed, 
 and of carbonic acid produced, as water is like- 
 wife formed in ail experiments upon vegetable 
 and animal matters which contain an excefs of 
 hydrogen, this apparatus can neither coiled it 
 nor determine its quantity. The experiment 
 with phofphorus is even incomplete in this w r ay, 
 as it is impodible to demonflrate that the weight 
 of the phofphoric acid produced is equal to the 
 fum of the weights of the phofphorus burnt and 
 oxygen gas abforbed during the procefs. I have 
 been therefore obliged to vary the inllruments 
 according to circumflances, and to employ fe- 
 veral of different kinds, which I fhali defcribe 
 in their order, beginning with that ufed for 
 burning phofphorus. 
 
 Take a large balloon, A, PL IV. Fig. 4. of 
 criftal or white glafs, with an opening, EF, about 
 two inches and a half, or three inches, diame- 
 ter, to which a cap of brafs is accurately fitted 
 with emery, and which has two holes for the 
 paffage of the tubes xxx, yyy. Before {hutting 
 the balloon with its cover, place within it the 
 Hand, BC, fupporting the cup of porcelain, D, 
 which contains the phofphorus. Then lute on 
 the cap with fat lute, and allow it to dry for 
 feme days, and weigh the whole accurately ; 
 
422 
 
 ELEMENTS 
 
 after this exhaufl the balloon by means of an 
 air-pump conne&ed with the tube xxx, and fill 
 it with oxygen gas by the tubeyyy, from the 
 gazometer, PI. VIII. Fig. i. defcribed Chap. II. 
 Se£t, II. of this part. The phofphorus is then 
 fet on fire by means of a burningglafs, and is 
 allowed to burn till the cloud of concrete phof- 
 phoric acid flops the combuftion, oxygen gas 
 being continually fupplied from the gazometer. 
 When the apparatus has cooled, it is weighed 
 and unluted ; the tare of the inftrument being 
 allowed, the weight is that of the phofphoric 
 acid contained. It is proper, for greater accu- 
 racy, to examine the air or gas contained in the 
 balloon after combuftion, as it may happen to 
 be foinewhat heavier or lighter than common 
 air; and this difference of weight rnuft be taken 
 into account in the calculations upon the refults 
 of the experiment, 
 
 SECT. III. 
 
 Of the Combuftion of Charcoal . 
 
 The apparatus I have employed for this pro- 
 cefs confifts of a fmall conical furnace of ham- 
 mered copper, reprefented in perfpedtive, PI. XU. 
 Fig. 9. and internally difplayed Fig. 11. It is 
 
 divided 
 
OF CHEMISTRY. 
 
 423 
 
 divided into the furnace, ABC, where the char- 
 coal is burnt, the grate, de , and the afh- hole, 
 F ; the tube, GH, in the middle of the dome 
 of the furnace ferves to introduce the charcoal, 
 and as a chimney for carrying off the air which 
 has ferved for combuftion. Through the tube, 
 Imn, which communicates with the gazometer, 
 the hydrogen gas, or air, intended for fupport- 
 ing the combuftion, is conveyed into the afh- 
 hole, F, whence it is forced, by the application 
 of preffure to the gazometer, to pafs through the 
 grate, de , and to blow upon the burning char- 
 coal placed immediately above. 
 
 Oxygen gas, which forms 0 f atmofpheric 
 air, is changed into carbonic acid gas during 
 combuftion with charcoal, whilft the azotic gas 
 of the air is not altered at all. Hence, after 
 the combuftion of charcoal in atmofpheric air, 
 a mixture of carbonic acid gas and azotic gas 
 muft remain ; to allow this mixture to pafs off, 
 the tube, op> is adapted to the chimney, GH, 
 by means of a fcrew at G, and conveys the gas 
 into bottles half filled with folution of cauftic 
 potafh. The carbonic acid gas is abforbed by 
 the alkali, and the azotic gas is conveyed into 
 a fecond gazometer, where its quantity is afcer- 
 tained. 
 
 The weight of the furnace, ABC, is firft ac- 
 curately determined, then introduce the tube 
 RS, of known weight, by the chimney, GH, 
 
 til! 
 
4H ELEMENTS 
 
 till its lower end S, refts upon the grate, de , 
 which it occupies entirely ; in the next place, 
 till the furnace with charcoal, and weigh the 
 whole again, to know the exa£t quantity of 
 charcoal fubmitted to experiment. The furnace 
 is now put in its place, the tube, / m n, is 
 fcrewed to that which communicates with the 
 gazometer, and the tube, op, to that which 
 communicates with the bottles of alkaline folu- 
 tion. Every thing being in readinefs, the flop- 
 cock of the gazometer is opened, a fmall piece 
 of burning charcoal is thrown into the tube, RS, 
 which is inltantly withdrawn, and the tube, op, 
 is fcrewed to the chimney, GH. The little 
 piece of charcoal falls upon the grate, and in 
 this manner gets below the whole charcoal, and 
 is kept on fire by the ftream of air from the ga- 
 zometer. To be certain that the combuftion is 
 begun, and goes on properly, the tube, qrs, is 
 fixed to the furnace, having a piece of glafs ce- 
 mented to its upper extremity, s , through which 
 we can fee if the charcoal be on fire. 
 
 I negle&ed to obferve above, that the furnace, 
 and its appendages, are plunged in water in the 
 cittern, TVXY, Fig. n. PI. XII. to which ice 
 may be added to moderate the heat, if neceflary ; 
 though the heat is by no means very confide- 
 rable, as there is no air but what comes from 
 the gazometer, and no more of the charcoal 
 
 burns 
 
OF CHEMISTRY. 
 
 425 
 
 burns at one time than what is immediately 
 over the grate. 
 
 As one piece of charcoal is confumed an- 
 other falls down into its place, in confequence 
 of the declivity of the fides of the furnace ; this 
 gets into the ftream of air from the grate, de , 
 and is burnt ; and fo on, fuccefiively, till the 
 whole charcoal is confumed. The air which 
 has ferved the purpofe of the combuftion pafles 
 through the mafs of charcoal, and is forced by 
 the preffure of the gazometer to efcape through 
 the tube, op , and to pafs through the bottles 
 of alkaline folution. 
 
 This experiment furnilhes all the neceflary 
 data for a complete analyfis of atmofpheric air 
 and of charcoal. We know the weight of char- 
 coal confumed ; the gazometer gives us the 
 meafure of the air employed ; the quantity and 
 quality of gas remaining after combuftion may 
 be determined, as it is received, either in an- 
 other gazometer, or in jars, in a pneumato-che- 
 mical apparatus ; the weight of allies remain- 
 ing in the afh-hole is readily *afcertained ; and, 
 finally, the additional weight acquired by the 
 bottles of alkaline folution gives the exacl quan- 
 tity of carbonic acid formed during the procefs. 
 By this experiment we may likewife determine, 
 with fufficient accuracy, the proportions in 
 which charcoal and oxygen enter into the coin- 
 pofition of carbonic acid. 
 
 3 H la 
 
 
42 6 
 
 ELEMENTS 
 
 In a future memoir I fhall give an account 
 to the Academy of a feries of experiments I 
 have undertaken, with this inftrument, upon all 
 the vegetable and animal charcoals. By fome 
 very flight alterations, this machine may be 
 made to anfwer for obferving the principal phe- 
 nomena of refpiration. 
 
 SECT, IV. 
 
 Of the Combujlion of Oils . 
 
 Oils are more compound in their nature than 
 charcoal, being formed by the combination of 
 at lead two elements, charcoal and hydrogen ; 
 of courfe, after their combuftion in common 
 air, water, carbonic acid gas, and azotic gas, 
 remain. Hence the apparatus employed for 
 their combuftion requires to be adapted for 
 collecting thefe three products, and is confe- 
 quently more complicated than the charcoal 
 furnace. 
 
 The apparatus I employ for this purpofe is 
 compofed of a large jar or pitcher A, PI. XII. 
 Fig. 4. furrounded at its upper edge by a rim of 
 iron properly cemented at DE, and receding 
 from the jar at BC, fo as to leave a furrow or 
 gutter X#. between it and the cutfide of the jar, 
 
 fomewhat 
 
OF CHEMISTRY. 
 
 427 
 
 iomewhat more than two inches deep. The 
 cover or lid of the jar, Fig. 5. is likewife fur- 
 rounded by an iron rim fg y which adjufts into 
 the gutter xx 9 Fig. 4. which being filled with 
 mercury, has the effeft of doling the jar her- 
 metically in an inftant, without ufing any lute ; 
 and, as the gutter will hold about two inches 
 of mercury, the air in the jar may be made to 
 fuftain the preffure of more than two feet of 
 water, without danger of its efcapr g. 
 
 The lid has four holes, T h i k , for the paffage 
 of an equal number of tubes. The opening T 
 is furnifhed with a leather box, through which 
 paffes the rod. Fig. 3. intended for raifing and 
 iowering the wick of the lamp, as will be after- 
 wards dire&ed. The three other holes are in- 
 tended for the paffage of three feveral tubes, 
 one of which conveys the oil to the lamp, a fe- 
 con 4 conveys air for keeping up the combuf- 
 tion, and the third carries off the air, after it 
 has ferved for combuftion. The lamp in which 
 the oil is burnt is reprefented Fig. 2 ; a is the 
 refervoir of oil, having a funnel by which it is 
 filled; bcdefgh is a fyphon which conveys 
 the oil to the lamp 1 1 ; 7, 8, 9, 10, is the tube 
 which convevs the air for combuftion from the 
 gazometer to the fame lamp. The tube be is 
 formed externally, at its lower end b\ into a 
 male ferew, which turns in a female ferew in the 
 hd of the refervoir of oil a ; fo that, by turning 
 
 the 
 
428 ELEMENTS 
 
 the refervoir one way or the other, it is made 
 to rife or fall, by which the oil is kept at the 
 neceffary level. 
 
 When the fyphon is to be filled, and the 
 communication formed between the refervoir of 
 oil and the lamp, the flop-cock c is fhut, and 
 that at e opened, oil is poured in by the open- 
 ing f at the top of the fyphon, till it rifes with- 
 in three or four lines of the upper edge of the 
 lamp, the flop-cock k is then fhut, and that at 
 c opened ; the oil is then poured in at/, till the 
 branch bed of the fyphon is filled, and then the 
 flop-cock e is clofed. The two branches of the 
 fyphon being now completely filled, a commu- 
 nication is fully eflablifhed between the refer- 
 voir and the lamp. 
 
 In PI. XII. Fig. i. all the parts of the lamp 
 ii, Fig. 2. are reprefented magnified, to fhow 
 them di(lin£lly. The tube i k carries the oil 
 from the refervoir to the cavity a a a #, which 
 contains the wick ; the tube 9, 10, brings the 
 air from the gazometer for keeping up the com- 
 buflion ; this air fpreads through the cavity 
 ddddj and, by means of the paffages cccc and 
 bbbb, is diflributed on each fide of the wick, 
 after the principles of the lamps conflrufled by 
 Argand, C)uinquet, and Lange. 
 
 To render the whole of this complicated ap- 
 paratus more eafily underflood, and that its de- 
 scription may make all others of the fame kind 
 
 more 
 
OF CHEMISTRY. 
 
 429 
 
 more readily followed, it is reprefented, com- 
 pletely connected together for ufe, in PI. XT, 
 The gazometer P furnifhes air for the combuf- 
 tion by the tube and flop- cock 1,2; the tube 
 2, 3, communicates with a fecond gazometer, 
 which is filled whiift the firft one is emptying du- 
 ring the procefs, that there may be no interrup- 
 tion to the combuftion ; 4, 5, is a tube of gtafs 
 filled with deliquefcent falts, for drying the air 
 as much as poflible in its paffage ; and the 
 weight of this tube and its contained falts, at 
 the beginning of the experiment, being known, 
 it is eafy to determine the quantity of water ab- 
 sorbed by them from the air. From this deli- 
 quefcent tube the air is condu&ed through the 
 pipe 5, 6, 7, 8, 9, 10, to the lamp 1 1, where it 
 Spreads on both Sides of the wick, as before de- 
 scribed, and feeds the flame. One part of this 
 air, which ferves to keep up the combuftion. of 
 the oil, forms carbonic acid gas and water, by 
 oxygenating its elements. Part of this water 
 condenfes upon the Tides of the pitcher A, and 
 another part is held in folution in the air by 
 means of caloric furnifhed by the combuftion. 
 This air is forced by the compreflion of the ga- 
 zometer to pafs through the tube 12, 13, 14, 
 15, into the bottle 16, and the worm 17, 18, 
 where the water is fully condenfed from the re- 
 frigeration of the air ) and, if any water (fill re- 
 mains 
 
43 ° 
 
 ELEMENTS 
 
 mains in foliation, it is abforbed by deliquefcent 
 falts contained in the tube 19, 20. 
 
 Ail thefe precautions are folely intended for 
 collecting and determining the quantity of wa- 
 ter formed during the experiment ; the carbo- 
 nic acid and azotic gas remains to be afcertain- 
 ed. The former is abforbed by cauftic alkaline 
 iblution in the bottles 22 and 25. I have only 
 reprefented two of thefe in the figure, but nine 
 at lead are requifite ; and the lad of the feries 
 may be half filled with lime-water, which is the 
 mod certain reagent for indicating the prefence 
 of carbonic acid ; if the lime-water is not ren- 
 dered turbid, we may be certain that no fenlible 
 quantity of that acid remains in the air. 
 
 The red of the air which has ferved for com- 
 bullion, and which chiefly confids of azotic gas, 
 though dill mixed with a confiderable. portion 
 of oxygen gas, which has efcaped unchanged 
 from the combudion, is carried through a third 
 tube 28., 29, of deliquefcent falts, to deprive it 
 of any moidure it may have acquired in the bot- 
 tles of alkaline folution and lime-water, and 
 from thence by the tube 29, 30, into a gazo- 
 meter, where its quantity is afcertained. Small 
 eflays are then taken from it, which are expofed 
 to a folution of fulphuret of potafh, to afcertain, 
 the proportions of oxygen and azotic gas it con- 
 tains. 
 
 In 
 
OF CHEMISTRY. 
 
 43 5 
 
 
 In the combuftion of oils the wick becomes 
 charred at lad, and obftruCts the rife of the oil ; 
 befides, if we raife the wick above a certain 
 height, more oil rifes through its capillary tubes 
 than the dream of air is capable of confuming, 
 and fmoke is produced. Hence it is neceflary 
 to be able to lengthen or fhorten the wick with- 
 out opening the apparatus ; this is accomplifli- 
 ed by means of the rod 31, 32, 33, 34, which 
 pafles through a leather box, and is connected 
 with the fupport of the wick ; and that the mo- 
 tion of this rod, and confequently of the wick, 
 may be regulated with the utmoft fmoothnefs 
 and facility ; it is moved at pleafure by a pin- 
 nion which plays in a toothed rack. The rod, 
 with its appendages, are reprefented PI. XII. 
 Fig. 3. It appeared to me, that the combuftion 
 would be aflifted by furrounding the flame of 
 the lamp with a fmall glafs jar open at both 
 ends, as reprefented in its place in PI. XI. 
 
 I ftiall not enter into a more detailed defcrip- 
 tion of the conftruCtion of this apparatus, which 
 is (till capable of being altered and modified in 
 many refpeCts, but fhall only add, that when it 
 is to be ufed in experiment, the lamp and reler- 
 voir with the contained oil muft be accurately 
 weighed, after which it is placed as before di- 
 rected, and lighted ; having then formed the 
 connexion between the air in the gazometer 
 and the lamp, the external jar A, PI. XL is Ax- 
 ed 
 
43 * 
 
 ELEMENTS 
 
 ed over all, and fecured by means of the board 
 BC and two rods of iron which connefl: this 
 board with the lid, and are fere wed to it. A 
 fmall quantity of oil is burnt while the jar is ad- 
 jufting to the lid, and the product of that com- 
 bullion is loft ; there is likewife a fmall portion 
 of air from the gazometer loft at the fame time# 
 Both of thefe are of very inconfiderable confe- 
 quence in extenfive experiments, and they are 
 even capable of being valued in our calculation 
 of the refults. 
 
 In a particular memoir, I fhall give an ac- 
 count to the Academy of the difficulties infepa- 
 rable from this kind of experiments : Thefe are 
 fo infurmountable and troublefome, that I have 
 not hitherto been able to obtain any rigorous 
 determination of the quantities of the produ&s. 
 I have fufficient proof, however, that the fixed 
 oils are entirely refolved during combuftion in- 
 to water and carbonic acid gas, and confequent- 
 ly that they are compofed of hydrogen and 
 charcoal ; but I have no certain knowledge re- 
 fpe&ing the proportions of thefe ingredients. 
 
 SECT. 
 
OF CHEMISTRY. 
 
 433 
 
 SECT. V. 
 
 Of the Combuftion of AlkohoL 
 
 The combuftion of alkohol may be very readi- 
 ly performed in the apparatus already defcribed 
 for the combuftion of charcoal and phofphorus. 
 A lamp filled with alkohol is placed under the 
 jar A, Pi. IV. Fig. 3. a fmall morfel of phof- 
 phorus is placed upon the wick of the lamp, 
 which is fet on fire by means of the hot iron, as 
 before directed. This procefs is, however, li- 
 able to confiderable inconveniency ; it is dan- 
 gerous to make ufe of oxygen gas at the begin- 
 ning of the experiment for fear of deflagration, 
 which is even liable to happen when common 
 air is employed. An inftance of this had very 
 near proved fatal to myfelf, in prefence of fotne 
 members of the Academy. Inftead of preparing 
 the experiment, as ufual, at the time it was to 
 be performed, I had difpofed every thing in or- 
 der the evening before ; the atmofpheric air of the 
 jar had thereby fufficient time to diffolve a good 
 deal of the alkohol ; and this evaporation had 
 even been confiderably promoted by the height 
 of the column of mercury, which I had raifed 
 to EF, PI. IV. Fig. 3. The moment I attempt- 
 3 I ed 
 
434 
 
 ELEMENTS 
 
 ed to fet the little morfei of phofphorus on fire 
 by means of the red hot iron, a violent explo- 
 fion took place, which 'threw the jar with great 
 violence againft the floor of the laboratory, and 
 dalhed it in a thoufand pieces. 
 
 Hence we can only operate upon very frs.aH 
 quantities, fuch as ten or twelve grains of alko- 
 hol, in this manner ; and the errors which may 
 be committed in experiments upon fuch fmall 
 quantities prevents our placing any confidence 
 in their refults. I endeavoured to prolong the 
 combuftion, in the experiments contained in the 
 Memoirs of the Academy for 1784, p. 593. 
 by lighting the alkohoi firft in common air, and 
 furnifhing oxygen gas afterwards to the jar, in 
 proportion as it confumed ; but the carbonic 
 acid gas produced by the procefs became a great 
 hinderance to the combuftion, the more fo that 
 alkohoi is but difficultly combuftible, efpecially 
 in worfe than common air ; fo that even in this 
 way very fmall quantities only could be burnt. 
 
 Perhaps this combuftion might fucceed better 
 in the oil apparatus, PI. XI. ; but I have not 
 hitherto ventured to try it. The jar A in which 
 the combuftion is performed is near 1400 cubi- 
 cal inches in dimenfion ; and, were an explo- 
 fion to take place in fuch a veffel, its confe- 
 quences would be very terrible, and very diffi- 
 cult to guard againft. I have not, however, 
 defpaired of making the attempt. 
 
 From 
 
OF CHEMISTRY. 
 
 435 
 
 From all thefe difficulties, I have been hither- 
 to obliged to confine myfelf to experiments up- 
 on very fmail quantities of alkohol, or at lead 
 to combuflions made in open veflels, fuch as 
 that reprefented in PI. IX. Fig. 5. which will 
 be defcribed in Section VII. of this chapter. If 
 I am ever able to remove thefe difficulties, I 
 fhall refume this inveftigation. 
 
 SECT. VI. 
 
 Of the Combuftion of Ether. 
 
 Tho* the combuftion of ether in clofe veflels 
 does not prefent the fame difficulties as that of 
 alkohol, yet it involves fome of a different kind, 
 not more eafily overcome, and which ftill pre- 
 vent the progrefs of my experiments. I endea- 
 voured to profit by the property which ether 
 poflefles of diffolving in atmofpheric air, and 
 rendering it inflammable without explofion. 
 For this purpofe, I conftru&ed the refervoir of 
 ether a b c d, Plate XII. Fig. 8. to which air is 
 brought from the gazometer by the tube 1, 2, 
 3, 4. This air fpreads, in the firft place, in the 
 double lid ac of the refervoir, from which it 
 pafles through feven tubes ef gh , ik 9 &c. which 
 defcend to the bottom of * the ether, and it is 
 
 forced 
 
43 6 E L E M E N T S 
 
 forced by the preffure of the gazometer to boil 
 up through the ether in the refervoir. We 
 may replace the ether in this firft refervoir, in 
 proportion as it is diffolved and carried off by 
 the air, by means of the fupplementary refer- 
 voir E, connected by a brafs tube fifteen or 
 eighteen inches long, and fhut by a flop-cock. 
 This length of the conneding tube is to enable 
 the defcending ether to overcome the refiftance 
 occafioned by the preffure of the air from the 
 gazometer. 
 
 The air, thus loaded with vapours of ether, 
 is conduded by the tube 5, 6, 7, 8, 9, to the 
 jar A, into which it is allowed to efcape through 
 a capillary opening, at the extremity of which 
 it is fet on fire. The air, when it has ferved 
 the purpofe of combuftion, paffes through the 
 bottle 1 6, PI. XI. the worm 17, 18, and the 
 deliquefcent tube 19, 20, after which it paffes 
 through the alkaline bottles ; in thefe its car- 
 bonic acid gas is abforbed, the water formed 
 during the experiment having been previoufly 
 depofited in the former parts of the apparatus. 
 
 When I caufed conftrud this apparatus, I 
 fuppofed that the combination of atmofpheric air 
 and ether formed in the refervoir abed , PL XII. 
 Fig. 8. was in proper proportion for fupporting 
 combuftion; but in this I was miftaken ; for 
 there is a very confiderable quantity of excefs of 
 ether ; fo that an additional quantity of atmo- 
 fpheric 
 
OF CHEMISTRY. 
 
 437 
 
 fpheric air is neceflfary to enable it to burn fully. 
 Hence a lamp conftructed upon thefe principles 
 will burn in common air, which furniflies the 
 quantity of oxygen necelfary for combuftion, 
 but will not burn in clofe velfels in which the 
 air is not renewed. From this circumftance, 
 my ether lamp went out foon after being light- 
 ed and fhut up in the jar A, PI. XII. Fig. 8. 
 To remedy this defeat, I endeavoured to bring 
 atmofpheric air to the lamp by ths lateral tube 
 io, ii, 12, 13, 14, 15, which I diftributed 
 circularly round the flame ; but the flame is fo 
 exceedingly rare, that it is blown out by the 
 gentled poflible ftream of air, fo that I have not 
 hitherto fucceeded in burning ether. I do not, 
 however, defpair of being able to accomplifh it 
 by means of fome changes I am about to have 
 made upon this apparatus. 
 
 S E C T. vir. 
 
 Of the Combuftion of Hydrogen Gas , and the For - 
 mation of Water, 
 
 In the formation of water, two fubftaiices, 
 hydrogen and oxygen, which are both in the 
 aeriform ftate before combuftion, are tranf- 
 formed into liquid or water by the operation. 
 
 This 
 
438 ELEMENTS 
 
 k 
 
 This experiment would be very eafy, and would 
 require very Ample inftruments, if it were pof- 
 flble to procure the two gaffes perfe&ly pure, 
 fo that they might burn without any refi- 
 duum. We might, in that cafe, operate in very 
 fmall veflels, and, by continually furnifhing the 
 two gafles in proper proportions, might conti- 
 nue the combuftion indefinitely. But, hitherto, 
 chemifts have only employed oxygen gas, mix- 
 ed with azotic gas ; from which circumftance, 
 they have only been able to keep up the com- 
 buftion of hydrogen gas for a very limited time 
 in clofe veflels, becaufe, as the refiduum of azo- 
 tic gas is continually increafing, the air be- 
 comes at laft fo much contaminated, that the 
 ' flame weakens and goes out. This inconveni- 
 ence is fo much the greater in proportion as the 
 oxygen gas employed is lefs pure. From this 
 circumftance, we muft either be fatisfied with 
 operating upon fmall quantities, or muft ex- 
 hauft the veflels at intervals, to get rid of the 
 refiduum of azotic gas ; but, in this cafe, a 
 portion of the water formed during the experi- 
 ment is evaporated by the exhauftion ; and the 
 refulting error is the more dangerous to the ac- 
 curacy of the procefs, that we have no certain 
 means of valuing it. 
 
 Thefe. conflderations make me defirous to 
 repeat the principal experiments of pneumatic 
 chemiftry with oxygen gas entirely free from 
 ' any 
 
OP CHEMISTRY. 4 $9 
 
 any admixture of azotic gas ; and thi$ may be 
 procured from oxygenated muriat of potafh. 
 The oxygen gas extra&ed from this fait does 
 not appear to contain azote, unlefs accidentally, 
 fo that, by proper precautions, it may be ob- 
 tained perfedly pure. In the mean time, the 
 apparatus employed by Mr Meufnier and me 
 for the combuftion of hydrogen gas, which is 
 defcribed in the experiment for recompofition 
 of water, Part I. Chap. VIII. and need not be 
 here repeated, will anfwer the purpofe ; when 
 pure gaffes are procured, this apparatus will re- 
 quire no alterations, except that the capacity 
 of the veffels may then be diminifhed. See 
 PI. IV. Fig. 5. 
 
 The combuftion, when once begun, conti- 
 nues for a confiderable time, but weakens gra- 
 dually, in proportion as the quantity of azotic 
 ga? remaining from the combuftion increafes, 
 till at laft the azotic gas is in fuch over propor- 
 tion that the combuftion can no longer be fup* 
 ported, and the flame goes out. This fponta- 
 neous extinction muft be prevented, becaufe, as 
 the hydro'gen gas is preffed upon in its refer - 
 voir, by an inch and a half of water, whilft the 
 oxygen gas fuflers a preffure only of three lines, 
 a mixture of the two would take place in the 
 balloon, which would at laft be forced by the 
 fuperior preffure into the refervoir of oxygen 
 gas. Wherefore the combuftion muft be flop- 
 ped, 
 
ELEMENTS 
 
 440 
 
 ped, by (hutting the (top-cock of the tube d'Dd 
 whenever the flame grows very feeble ; for 
 which purpofe it mud be attentively watch- 
 ed. 
 
 There is another apparatus for combuftion, 
 which, though we cannot with it perform ex- 
 periments with the fame fcrupulous exadtnefs as 
 with the preceding inftruments, gives very (tri- 
 king refults that are extremely proper to be 
 (hewn in courfes of philofophical chemiftry. It 
 confifts of a worm EF, PL IX. Fig. 5. contained 
 in a metallic cooller ABCD. To the upper 
 part of this worm E, the chimney Gli is fixed, 
 which is compofed of two tubes, the inner of 
 which is a continuation of the worm, and the 
 outer one is a cafe of tin-plate, which furrounds 
 it at about an inch diftance, and the interval is 
 filled up with fand. At the inferior extremity 
 K of the inner tube, a glafs tube is fixed, to 
 which we adopt the Argand lamp LM for burn- 
 ing alkohol, &c. 
 
 Things being thus difpofed, and the lamp 
 being filled with a determinate quantity of alko- 
 hol, it is fet on fire ; the water which is formed 
 during the combuftion rifes in the chimney KE, 
 and being ccndenfed in the worm, runs out at 
 its extremity F into the bottle P. The double 
 tube of the chimney, filled with fand in the in- 
 terftice, is to prevent the tube from cooling in 
 its upper part, and condenfing the water ; o- 
 
 therwife. 
 
OF CHEMISTRY. 441 
 
 therwife, it would fall back in the tube, and we 
 fhould not be able to afcertain its quantity, and 
 befides it might fall in drops upon the wick, 
 and extinguifli the flame. The intention of this 
 conftru&ion, is to keep the chimney always hot, 
 and the worm always cool, rhat the water may 
 be preferved in the (late of vapour whilfl ri- 
 ling, and may be condenfed immediately upon 
 getting into the defending part of the appara- 
 tus. By this inftrument, which was contrived 
 by Mr Meufnier, and which is defcribed by me 
 in the Memoirs of the .Academy for 1 784, p. 
 593. we may, with attention to keep the worm 
 always cold, colledt nearly feventeen ounces of 
 water from the combuftion of fixteen ounces of 
 alkohol. 
 
 SECT. VIII. 
 
 Of the Oxydation of Metals . 
 
 The term oxydation or calcination is chiefly ti- 
 led to fignify the procefs by which metals expo- 
 fed to a certain degree of heat are converted 
 into oxyds, by abforbing oxygen from the air. 
 This combination takes place in confequence of 
 oxygen poflefling a greater affinity to metals, at 
 a certain temperature, than to caloric, which 
 3 K becomes 
 
442 
 
 ELEMENTS 
 
 becomes difengaged in its free flate •, but, a9 
 this difengagement, when made in common air* 
 is flow and progreflive, it is fcarcely evident to 
 the fenfes. It is quite otherwife, however, when 
 oxydation takes place in oxygen gas ; for, being 
 produced with much greater rapidity, it is ge- 
 nerally accompanied with heat and light, fo as 
 evidently to fhow that metallic fubftances are 
 real combuftible bodies. 
 
 All the metals have not the fame degree of 
 affinity to oxygen. Gold,filver, and platina, for 
 inftance, are incapable of taking it away from 
 its combination with caloric, even in the greateft 
 known heat ; whereas the other metals abforb it 
 in a larger or fmaller quantity, until the affini- 
 ties of the metal to oxygen, and of the latter to 
 caloric, are in exa£t equilibrium. Indeed, this 
 flate of equilibrium of affinities may be aflumed 
 as a general law of nature in all combina- 
 tions. 
 
 In all operations of this nature, the oxydation 
 of metals is accelerated by giving free accefs 
 to the air ; it is fometimes much aflifted by 
 joining the action of a bellows, which directs a 
 ftream of air over the furface of the metal. 
 This procefs becomes greatly more rapid if a 
 ftream of oxygen gas be ufed, which is readily 
 done by means of the gazometer formerly de« 
 fcribed. The metal, in this cafe, throws out a 
 brilliant flame, and the oxydation is very quick- 
 
 iy 
 
OF CHEMISTRY. 
 
 443 
 
 ly accomplifhed ; but this method can only be 
 ufed in very confined experiments, on account 
 of the expence of procuring oxygen gas. In 
 the eflay of ores, and in all the common opera- 
 tions of the laboratory, the calcination or oxy- 
 dation of metals is ufually performed in a difh 
 of baked clay, PI. IV. Fig. 6. commonly called 
 a roajling teji , placed in a ftrong furnace. The 
 fubftances to be oxydated are frequently ftirred, 
 on purpofe to prefent frefh furfaces to the air. 
 
 Whenever this operation is performed upon 
 ametal which is not volatile, and from which 
 nothing flies off into the furrounding air during 
 the procefs, the metal acquires additional 
 weight ; but the caufe of this increafed weight 
 during oxydation could never have been difco- 
 vered by means of experiments performed in 
 free air ; and it is only fince thefe operations 
 have been performed in clofe veflels, and in de- 
 terminate quantities of air, that any juft con- 
 jectures have been formed concerning the caufe 
 of this phenomenon. The firft method for 
 this purpofe is due to Dr Prieftley, who expo- 
 fes the metal to be calcined in a porcelain cup 
 N, PL IV. Fig. ii. placed upon the Hand IK, 
 under a jar A, in the bafon BCDE, full of wa- 
 ter ; the water is made to rife up to GH, by 
 fucking out the air with a fyphon, and the focus 
 of a burning glafs is made to fall upon the me- 
 tal. In a few minutes the oxydation takes place, 
 
 a 
 
444 ELEMENTS 
 
 a part of the oxygen contained in the air com- 
 bines with the metal, and a proportional dimi- 
 nution of the volume of air is produced ; what 
 remains is nothing more than azotic gas, ftill 
 however mixed with a fmall quantity of oxygen 
 gas. I have given an account of a feries of ex- 
 periments made with this apparatus in my Phy- 
 fical and Chemical Elfays, firfl: published in 
 1773. Mercury may be ufed inftead of water 
 in this experiment, whereby the refults are ren- 
 dered dill more conclufive. 
 
 Another procefs for this purpofe was invented 
 by Mr Boyle, and of which I* gave an account 
 in the Memoirs of the Academy for 1774, p. 
 351. The metal is introduced into a retort, 
 PL III. Fig. 20. the beak of which is hermeti- 
 cally fealed ; the metal is then oxy dated by 
 means of heat applied with great precaution. 
 The weight of the veflel, and its contained fub- 
 ftances, is not at all changed by this procefs, 
 until the extremity of the neck of the retort is 
 broken ; but, when that is done, the external 
 air ru fires in with a hilling noife. This opera- 
 tion is attended with danger, unlefs a part of 
 the air is driven out of the retort, by means of 
 heat, before it is hermetically fealed, as other- 
 wife the retort would be apt to burfl by the di- 
 lation of the air when placed in the furnace. 
 The quantity of air driven out may be received 
 under a jar in the pneumato-chemical appara- 
 tus, 
 

 OF CHEMISTRY. 445 
 
 : tus, by which its quantity, and that of the air 
 remaining in the retort, is afcertained. I have 
 not multiplied my experiments upon oxydation 
 of metals fo much as I could have wifhed ; nei- 
 ther have ^ obtained fatisfadory refults with a- 
 ny metal except tin. It is much to be wifhed 
 that fome perfon would undertake a feries of 
 experiments upon oxydation of metals in the 
 feveral gaffes ; the fubjed is important, and 
 would fully repay any trouble which this kind 
 of experiment might occafion. 
 
 As all the oxyds of mercury are capable of 
 revivifying without addition, and reftore the 
 oxygen gas they had before abforbed, this 
 feemed to be the mofl proper metal for beco- 
 ming the fubjed of conclufive experiments up- 
 on oxydation. I formerly endeavoured to ac- 
 complifh the oxydation of mercury in clofe vef- 
 fels, by filling a retort, containing a fmall quan- 
 tity of mercury, with oxygen gas, and adapting 
 a bladder half full of the fame gas to its beak ; 
 See PI. IV. Fig. 12. Afterwards, by heating 
 the mercury in the retort for a very long time, 
 1 fucceeded in oxydating a very fmall portion, 
 fo as to form a little red oxyd floating upon* the 
 furface of the running mercury ; but the quan- 
 tity was fo fmall, that the fmallefl error com- 
 mitted in the determination of the quantities of 
 oxygen gas before and after the operation mud 
 have thrown very great uncertainty upon the 
 
 refults 
 
44 § ELEMENTS 
 
 refults of the experiment. I was, befides, dif- 
 fatished with this procefs, and not without 
 caufe, left any air might have efcaped through 
 the pores of the bladder, more efpecially as it 
 becomes fhrivelled by the heat of ttfe furnace, 
 unlefs covered over with cloths kept conftantly 
 wet. 
 
 This experiment is performed with more cer- 
 tainty in the apparatus defcribed in the Me- 
 moirs of the Academy for 1775, p. 580. This 
 confifts of a retort, A, PI. IV. Fig. 2. having a 
 crooked glafs tube BCDE of ten or twelve lines 
 internal diameter, melted on to its beak, and 
 which is engaged under the bell glafs FG, 
 Handing with its mouth downwards, in a bafon 
 filled with water or mercury. The retort is 
 placed upon the bars of the furnace MMNN, 
 PI. IV. Fig. 2. or in a fand bath, and by means 
 of this apparatus we may, in the courfe of feve- 
 ral days, oxydate a fmall quantity of mercury 
 in common air ; the red oxyd floats upon the 
 furface, from which it may be colle&ed and re- 
 vivified, fo as to compare the quantity of oxy- 
 gen gas obtained in revivification with the ab- 
 forption which took place during oxydation. 
 This kind of experiment can only be performed 
 upon a fmall fcale, fo that no very certain con- 
 cluflons can be drawn from them *• 
 
 The 
 
 * See an account of this experiment, Part. I. Chap, 
 iii.— - A. 
 
OF CHEMISTRY. 447 
 
 The combuftion of iron in oxygen gas being 
 a true oxydation of that metal, ought to be 
 mentioned in this place. The apparatus em- 
 ployed by Mr Ingenhoufz for this operation is 
 reprefented in PI. IV. Fig. 17. ; but, having al- 
 ready defcribed it fufficiently in Chap. III. I fhall 
 refer the reader to what is faid of it in that 
 place. Iron may likewife be oxydated by com- 
 buflion in veffels filled with oxygen gas, in the 
 way already directed for phofphorus and char- 
 coal. This apparatus is reprefented PI. IV. 
 Fig. 3. and defcribed in the fifth chapter of the 
 firfl part of this work. We learn from Mr In- 
 genhoufz, that all the metals, except gold, fi- 
 ver, and mercury, may be burnt or oxydated 
 in the fame manner, by reducing them into very 
 fine wire, or very thin plates cut into narrow 
 flips ; thefe are twitted round with iron-wire, 
 which communicates the property of burning 
 to the other metals. 
 
 Mercury is even difficultly oxydated in free 
 air. In chemical laboratories, this procefs is 
 ufually carried on in a matrafs A, PI. IV. Fig. 
 having a very flat body, and a very long neck 
 BC, which veffel is commonly called Boyle’s 
 hell . A quantity of mercury is introduced fuf- 
 ficient to cover the bottom, and it is placed in 
 a fand-bath, which keeps up a conflant heat 
 approaching to that of boiling mercury. By 
 continuing this operation with five or fix fimi- 
 lar matraffes during feveral months, and re- 
 newing 
 
448 ELEMENTS 
 
 newing the mercury from time to time, a few 
 ounces of red oxyd are at laft obtained. The 
 great flownefs and inconvenience of this appa- 
 ratus arifes from the air not being fufficiently 
 renewed ; but if, on the other hand, too free a 
 circulation were given to the external air, it 
 would carry off the mercury in folution in the 
 ftate of vapour, fo that in a few days none 
 would remain in the veffel. 
 
 As, of all the experiments upon the oxyda- 
 tion of metals, thofe with mercury are the moft 
 conclufive, it were much to be wifhed that a 
 fimple apparatus could be contrived by which 
 this oxydation and its refults might be demon- 
 llrated in public courfes of chemiftry. This 
 might, in my opinion, be accomplifhed by me- 
 thods fimilar to thofe I have already defcribed 
 for the combuftion of charcoal and the oils ; 
 but, from other purfuits, I have not been able 
 hitherto to refume this kind of experiment. 
 
 The oxyd of mercury revives without addi- 
 tion, by being heated to a flightly red heat. In 
 this degree of temperature, oxygen has greater 
 affinity to caloric than to mercury, and forms 
 oxygen gas. This is always mixed with a fmall 
 portion of azotic gas, which indicates that the 
 mercury abforbs a fmall portion of this latter 
 gas during oxydation. It almofl always con- 
 tains a little carbonic acid gas, which mult un- 
 doubtedly be attributed to the foulneffes of the 
 
 oxyd $ 
 
 / 
 
OF CHEMISTRY. 
 
 449 
 
 oxyd ; thefe are charred by the heat, and con- 
 vert a part of the oxygen gas into carbonic a- 
 cid. 
 
 If cbemifts were reduced to the neceiTity of 
 procuring all the oxygen gas employed in their 
 experiments from mercury oxydated by heat 
 without addition, or, as it is called, calcined or 
 precipitated per fe, the excedive dearnefs of 
 that preparation would render experiments, e- 
 ven upon a moderate fcale, quite impra&icable. 
 But mercury may likewife be oxydated by 
 means of nitric acid ; and in this way we pro- 
 cure a red oxyd, even more pure than that pro- 
 duced by calcination. I have fometirrxes pre- 
 pared this oxyd by diiToiving mercury in nitric 
 acid, evaporating to drynefs, and calcining the 
 fait, either in a retort, or in capfules formed 
 of pieces of broken matraffes and retorts, in 
 the manner formerly defcribed ; but I have ne- 
 ver fucceeded in making it equally beautiful 
 with what is fold by the druggifts, and which 
 is, I believe, brought from Holland. In choo- 
 ling this, we ought to prefer what is in foiid 
 lumps compofed of foft adhering fcales, as when 
 in powder it is fornetimes adulterated with red 
 oxyd of lead. 
 
 To obtain oxygen gas from the red oxyd of 
 mercury, I ufuaily employ a porcelain retort, 
 having a long glafs tube adapted to its beak, 
 which is engaged under jars in the water pneu- 
 
 7. L nrato- 
 
45c ELEMENTS 
 
 mato-chemical apparatus, and I place a bottle 
 in the water, at the end of the tube, for recei- 
 ving the mercury, in proportion as it revives 
 and diftils over. As the oxygen gas never ap- 
 pears till the retort becomes red, it feems to 
 prove the principle eftablifhed by Mr Berthol- 
 let, that an obfcure heat can never form oxygen 
 gas, and that light is one of its conftituent ele- 
 ments. We mult rejed the firlt portion of gas 
 which comes over, as being mixed with com- 
 mon air, from what was contained in the re- 
 tort at the beginning of the experiment ; but, 
 even with this precaution, the oxygen gas pro- 
 cured is ufually contaminated with a tenth part 
 of azotic gas, and with a very fniali portion of 
 carbonic acid gas. This latter is readily got 
 rid of, by making the gas pafs through a folu- 
 tion of cauftic alkali ; but we know of no me- 
 thod for Separating the azotic gas ; its propor- 
 tions may however be afcertained, by leaving 
 a known quantity of the oxygen gas contami- 
 nated with it for a fortnight, in contad with 
 fulphuret of foda or potalh, which abforbs the 
 oxygen gas fo as to convert the fuiphur into 
 fulphuric acid, and leaves the azotic gas re- 
 maining pure. 
 
 We may likewife procure oxygen gas from 
 black oxyd of manganefe or nitrat of potalh, 
 by expofing them to a red heat in the appara- , 
 tus already defcribed for operating upon red 
 
 oxyd 
 
oxyd of mercury ; only, as it requires fuch a 
 heat as is at leaft capable of foftening glafs, we 
 muft employ retorts of (tone or of porcelain. 
 But the pureft and belt oxygen gas is what is 
 difengaged from oxygenated muriac of potafh 
 by fimple heat. This operation is performed 
 in a glafs retort, and the gas obtained -is per- 
 fectly pure, provided that the firfl portions, 
 which are mixed with the common air of the 
 veflels, be rejected. 
 
45 * 
 
 ELEMENTS 
 
 CHAP. IX. 
 
 Of Deflagration . 
 
 *¥ HAVE already fliown, Part I. Chap. IX, 
 1 that oxygen does not always part with the 
 whole of the caloric it contained in the date of 
 gas when it enters into combination with other 
 bodies. It carries almoft the whole of its calo- 
 ric alonglt with it in entering into th£ combi- 
 nations which form nitric acid and oxygenated 
 muriatic acid ^ fo that in nitrats, and more efpe- 
 cially in oxygenated muriats, the oxygen is, in 
 a certain degree, in the hate of oxygen gas, 
 condenfed, and reduced to the fmalieft volume 
 it is capable of occupying. 
 
 In thefe combinations, the caloric exerts a 
 conftant action upon the oxygen to bring it 
 back to the (late of gas ; hence the oxygen ad- 
 heres but very flightly, and the fmalleft addi- 
 tional force is capable of fetting it free ; and, 
 when fuch force is applied, it often recovers the 
 {late of gas inflantaneoufly. This rapid paffage 
 from the folid to the aeriform date is called 
 detonation, or fulmination, becaufe it is ufually 
 accompanied with noife and expiofion. Defla- 
 grations are commonly produced by means .of 
 combinations of charcoal either with nitre or 
 
 oxygenated 
 
OF CHEMISTRY, 
 
 453 
 
 oxygenated muriat of potafh ; fometimes, to af- 
 fift the inflammation, fulphur is added ; and, 
 upon the juft proportion of thefe ingredients, 
 and the proper manipulation of the mixture, 
 depends the art of making gun-powder. 
 
 As oxygen is changed, by deflagration with 
 charcoal, into carbonic acid, inftead of oxygen 
 gas, carbonic acid gas is difengaged, at leaft 
 when the mixture has been made in juft pro- 
 portions. In deflagration with nitre, azotic 
 gas is likewife difengaged, becaufe azote is one 
 of the conftituent elements of nitric acid. 
 
 The fudden and inftantaneous difengage- 
 ment and expanfion of thefe gaffes is not, how- 
 ever, fufficient for explaining all the phenome- 
 na of deflagration ; becaufe, if this were the foie 
 operating power, gun powder would always be 
 fo much the ftronger in proportion as the quan- 
 tity of gas difengaged in a given time was the 
 more considerable, which does not always ac- 
 cord with experiment. I have tried fome kinds 
 which produced almoft double the effect of or- 
 dinary gun-powder, although they gave out a 
 fixth part lefs of gas during deflagration. It 
 would appear that the quantity of caloric difen- 
 gaged at the moment of detonation contributes 
 confiderably to the expanfive effects produced ; 
 for, although caloric penetrates freely through 
 the pores of every body in nature, it can only 
 do fo progreflively, and in a given time ; hence* 
 
 when 
 
454 
 
 ELEMENTS 
 
 when the quantity difengaged at once is toa 
 large to get through the pores of the furround- 
 ing bodies, it muff neceffarily adt in the fame 
 way with ordinary elaftic fluids, and overturn 
 every thing that oppofes its paffage. This muft, 
 at leaft in part, take place when gun-powder is 
 fet on fire in a cannon ; as, although the metal 
 is permeable to caloric, the quantity difengaged 
 at once is too large to find its way through the 
 pores of the metal, it muft therefore make an 
 effort to efcape on every lide ; and, as the re- 
 fiftance all around, excepting towards the muz- 
 zle, is too great to be overcome, this effort is 
 employed for expelling the bullet. 
 
 The caloric produces a fecond effedl, by 
 means of the repulfive force exerted between 
 its particles ; it caufes the gaffes, difengaged at 
 the moment of deflagration, to expand with a 
 degree of force proportioned to the temperature 
 produced. 
 
 It is very probable that water is decompcfed 
 during the deflagration of gun-powder, and that 
 part of the oxygen furnifhed to the nafcent car- 
 bonic acid gas is produced from it. If fo, a 
 confiderable quantity of hydrogen gas mull: be 
 difengaged in the inflant of deflagration, which 
 expands, and contributes to the force of the ex- 
 plofion. It may readily be conceived how great- 
 ly this circumftance muft increafe the effedt of 
 powder, if we confider that a pint of hydrogen 
 • gas 
 
CHEMISTRY. 
 
 455 
 
 gas weighs only one grain and two thirds; 
 hence a very fmali quantity in weight muit oc- 
 cupy a very large fpace, and it mull exert a 
 prodigious expanfive force in pafSng from the 
 liquid to the aeriform ftate of exiftence. 
 
 In the laft place, as a portion of undecom- 
 pofed water is reduced to vapour during the 
 deflagration of gun-powder, and as water, in 
 the ftate of gas, occupies feventeen or eighteen 
 hundred times more fpace than in its liquid 
 ftate, this circumftance muft likewife contribute 
 largely to the explofive force of the powder, 
 
 I have already made a confiderable feries of 
 experiments upon the nature of the elaftic fluids 
 difengaged during the deflagration of nitre with 
 charcoal and fulphur ; and have made fome, 
 likewife, with the oxygenated muriat of potalh. 
 This method of inveftigation leads to tollerably 
 accurate conclufions with refped: to the confti- 
 tuent elements of thefe falts. Some of the prin- 
 cipal refults of thefe experiments, and of the 
 confequences drawn from them refpe&ing the 
 analyfis of nitric acid, are reported in the col- 
 lection of memoirs prefented to the Academy 
 by foreign philofophers, vol xb p. 625. Since 
 then I have procured more convenient inftru- 
 ments, and I intend to repeat thefe experiments 
 upon a larger fcale, by which I fhail procure 
 more accurate precifion in their refults ; the 
 following, however, is the procefs I hav'e hither- 
 to 
 
456 ELEMENT* 
 
 to employed. I would very earneftly advife fuch 
 as intend to repeat fome of thefe experiments* 
 to be very much upon their guard in operating 
 upon any mixture which contains nitre, char- 
 coal, and fulphur, and more efpecially with thofe 
 In which oxygenated muriat of potafh is mixed 
 with thefe two materials. 
 
 I make ufe of piftol barrels, about fix inches 
 long, and of five or fix lines diameter, having 
 the touch-hole fpiked up with an iron nail 
 itrongiy driven in, and broken in the hole, and 
 a little tin-fmith’s folder run in to prevent any 
 poffible iffue for the air. Thefe are charged 
 with a mixture of known quantities of nitre and 
 charcoal, or any other mixture capable of de- 
 flagration, reduced to an impalpable powder, 
 and formed into a pafte with a moderate quan- 
 tity of water. Every portion of the materials 
 introduced muft be rammed down with a ram- 
 mer nearly of the fame caliber with the barrel, 
 four or five lines at the muzzle muft be left 
 empty, and about two inches of quick match 
 are added at the end of the charge. The only 
 difficulty in this experiment, efpecially when ful- 
 phur is contained in the mixture, is to difcover 
 the proper degree of moiltening ; for, if the 
 pafte be too much wetted, it will not take fire, 
 and if too dry, the deflagration is apt to become 
 too rapid, and even dangerous. 
 
 When 
 
OF CHEMISTRY. 
 
 4 57 
 
 When the experiment is not intended to be 
 rigoroufly exa&, we fet fire to the match^ and, 
 when it is juft about to communicate with the 
 charge, we plunge the piftol below a large bell- 
 glafs full of water, in the pneumato- chemical 
 apparatus. The deflagration begins, and conti- 
 nues in the water, and gas is difengaged with 
 lefs or more rapidity, in proportion as the mix- 
 ture is more or lefs dry. So long as the defla- 
 gration continues, the muzzle of the piftol mufl 
 be kept fomewhat inclined downwards, to pre- 
 vent the water from getting into its barrel. In 
 this manner I have fometimes collected the gas 
 produced from the deflagration of an ounce and 
 half, or two ounces, of nitre. 
 
 In this manner of operating it is impoflible to 
 determine the quantity of carbonic acid gas dif- 
 engaged, becaufe a part of it is abforbed by the 
 water while palling through it ; but, when the 
 carbonic acid is abforbed, the azotic gas re- 
 mains ; and, if it be agitated for a few minutes 
 in cauftic alkaline folution, we obtain it pure, 
 and can eafily determine its volume and weight. 
 We may even, in this way, acquire a tolierably 
 exadt knowledge of the quantity of carbonic 
 acid by repeating the experiment a great many 
 times, and varying the proportions of charcoal, 
 till we find the exact quantity requifite to defla- 
 grate the whole nitre employed. Hence, by 
 means of the weight of charcoal employed, we 
 3 M determine 
 
45S ELEMENTS 
 
 determine the weight of oxygen neceffary for 
 faturation, and deduce the quantity of oxygen 
 contained in a given weight of nitre. 
 
 I have ufed another procefs, by which the 
 refults of this experiment are confiderably more 
 accurate, which confifts in receiving the difen- 
 gaged gaffes in bell-glaffes filled with mercury. 
 The mercurial apparatus I employ is large 
 enough to contain jars of from twelve to fifteen 
 pints in capacity, which are not very readily 
 managed when full of mercury, and even re- 
 quire to be filled by a particular method. When 
 the jar is placed in the ciftern of mercury, a 
 glafs fyphon is introduced, connected with a 
 finall air-pump, by means of which the air is 
 exhaufted, and the mercury rifes fo as to fill 
 the jar. After this, the gas of the deflagration 
 is made to pafs into the jar in the fame manner 
 as dire&ed when water is employed. 
 
 I muff again repeat, that this fpecies of ex- 
 periment requires to be performed with the 
 greatefl: pofiible precautions. I have fometimes 
 feen, when the difengagement of gas proceeded 
 with too great rapidity, jars filled with more 
 than an hundred and fifty pounds of mercury 
 driven off by the force of the explofion, and 
 broken to pieces, while the mercury was Mat- 
 tered about in great quantities. 
 
 When the experiment has fucceeded, and the 
 gas is colle&ed under the jar, its quantity in 
 
 general. 
 

 OF CHEMISTRY. 453 
 
 general, and the nature and quantities of the fe- 
 veral fpecies of gaffes of which the mixture is 
 compofed, are accurately afcertained by the me- 
 thods already pointed out in the fecond chapter 
 of this part of my work. I have been prevent- 
 ed from putting the laft hand to the experi- 
 ments I had begun upon deflagration, from their 
 connexion with the objects I am at prefent en- 
 gaged in ; and I am in hopes they will throw 
 confiderable light upon the operations belong- 
 ing to the manufacture of gun-powder. 
 
 CHAR 
 
*6o ELEMENTS 
 
 CHAP. X. 
 
 Of the Injlruments neceffary for Operating upon 
 Bodies in very high Temperatures . 
 
 E have already feen, that, by aqueous 
 
 folution, in which the particles of bo- 
 dies are feparated from each other, neither the 
 folvent nor the body held in folution are at all 
 decompofed ; fo that, whenever the caufe of fe- 
 paration ceafes, the particles reunite, and the 
 faline fubftance recovers precifely the fame ap- 
 pearance and properties it poffeffed before fo- 
 lution. Real folutions are produced by fire, 
 or by introducing and accumulating a great 
 quantity of caloric between the particles of bo- 
 dies ; and this fpecies of folution in caloric is 
 ufually called fufon . 
 
 This operation is commonly performed in 
 velfels called crucibles, which muft necefiarily 
 
 SECT. I. 
 
 Of Fufon, 
 
 be 
 
OF CHEMISTRY. 465 
 
 be lefs fufible than the bodies they are intended 
 to contain. Hence, in all ages, chemifts have 
 been extremely folicitous to procure crucibles 
 of very refractory materials, or fuch as are ca- 
 pable of refilling a very high degree of heat. 
 The belt are made of very pure clay or of por- 
 celain earth ; whereas fuch as are made of clay 
 mixed with calcareous or filicious earth are very 
 fufible. All the crucibles made in the neigh- 
 bourhood of Paris are of this kind, and conse- 
 quently unfit for moft chemical experiments. 
 The Heffian crucibles are tolerably good ; but 
 the bed: are made of Limoges earth, which 
 feems abfolutely infufible. We have, in France, 
 a great many clays very fit for making cruci- 
 bles ; fuch, for inltance, is the kind ufed for 
 making melting pots at the glafs-manufaCtory of 
 St Gobin. 
 
 Crucibles are made of various forms, accor- 
 ding to the operations they are intended to per- 
 form. Several of the moft common kinds are 
 reprefented PI. VII. Fig. 7. 8. 9. and 10. the 
 one reprefented at Fig. 9. is almoft fhut at its 
 mouth. 
 
 Though fufion may often take place without 
 changing the nature of the fufed body, this ope- 
 ration is frequently employed as a chemical means 
 of decompofing and recompounding bodies. In 
 this way all the metals are extra&ed from their 
 ores ; and, by this prccefs, they are revivified, 
 
 moulded, 
 
4^2 
 
 ELEMENTS 
 
 moulded, and alloyed with each other. By this 
 procefs fand and alkali are combined to form 
 glafs, and by it likewife paftes, or coloured 
 {tones, enamels, &c. are formed. 
 
 The action of violent fire was much more fre- 
 quently employed by the ancient chemifls than 
 it is in modern experiments. Since greater pre- 
 cifion has been employed in phiiofophical re- 
 fearches, the humid has been preferred to the 
 dry method of procefs, and fufion is feldom had 
 recourfe to until all the other means of analyfis 
 have failed. 
 
 SECT. II. 
 
 Of Furnaces . 
 
 Thefe are inftruments of molt univerfal ufe 
 in chemiftry ; and, as the fuccefs of a great 
 number of experiments depends upon their be- 
 ing well or ill conftru&ed, it is of great impor- 
 tance that a laboratory be well provided in this 
 refped. A furnace is a kind of hollow cylin- 
 drical tower, fometimes widened above, PI. XIII. 
 Fig. i. ABCD, which muft have at leaft two 
 lateral openings ; one in its upper part F, which 
 is the door of the fire-place, and one below, G, 
 leading to the afh-hole. Between thefe the fur- 
 nace 
 
I 
 
 OF CHEMISTRY. 463 
 
 nace is divided by a horizontal grate, intended 
 for fupporting the fewel, the fituation of which 
 is marked in the figure by the line HI. Though 
 this be the lead: complicated of all the chemical 
 furnaces, yet it is applicable to a great number 
 of purpofes. By it lead, tin, bifmuth, and, in 
 general, every fubftance which does not require 
 a very ftrong fire, may be melted in crucibles ; 
 it will ferve for metallic oxydations, for evapo- 
 ratory veflels, and for fand-baths, as in PI. III. 
 Fig. 1. and 2. To render it proper for thefe 
 purpofes, feverai notches, m m m m, PI. XIII. 
 Fig. 1. are made in its upper edge, as otherwife 
 any pan which might be placed over the fire 
 would flop the paffage of the air, and prevent 
 the fewel from burning. This furnace can on- 
 ly produce a moderate degree of heat, becaufe 
 the quantity of charcoal it is capable of con- 
 fuming is limited by the quantity of air which 
 is allowed to pafs through the opening G of 
 the afh-hole. Its power might be confiderablv 
 augmented by enlarging this opening, but then 
 the great ftream of air which is convenient for 
 fome operations might be hurtful in others ; 
 wherefore we mult have furnaces of different 
 forms, conftru&ed for different purpofes, in our 
 laboratories : There ought efpecially to be feve- 
 rai of the kind now defcribed of different fizes. 
 
 The reverberatory furnace, PI. XIII. Fig. 2. 
 is perhaps more neceffary. This, like the com- 
 mon 
 
46*4 
 
 ELEMENTS 
 
 mon furnace, is compofed of the affi-hole HIKL, 
 the fire-place KLMN, the laboratory MNOP, 
 and the dome RRSS, with its funnel or chim- 
 ney ITVV ; and to this laft feverai additional 
 tubes may be adapted, according to the nature 
 of the different experiments. The retort A is 
 placed in the divifion called the laboratory, and 
 fupported by two bars of iron which run acrofs 
 the furnace, and its beak comes out at a 
 round hole in the fide of the furnace, one half 
 cf which is cut in the piece called the labora- 
 tory, and the other in the dome. In moft of 
 the ready made reverberatory furnaces which 
 are fold by the potters at Paris, the openings 
 both above and below are too fmall : Thefe do 
 not allow a fufficient volume of air to pafs 
 through ; hence, as the quantity of charcoal 
 confumed, or, what is much the fame thing, 
 the quantity of caloric difengaged, is nearly in 
 proportion to the quantity of air which paffes 
 through the furnace, thefe furnaces do not 
 produce a fufficient effed in a great number of 
 experiments. To remedy this defed, there 
 ought to be two openings GG to the afh-hole ; 
 one of thefe is fhut up when only a moderate 
 fire is required ; and both are kept open when 
 the ftrongeft power of the furnace is to be ex- 
 erted. The opening of the dome SS ought 
 likewife to be confiderably larger than is ufually 
 made. 
 
 It 
 
OF CHEMISTRY. 4 65 
 
 It is of great importance not to employ re- 
 torts of too large fize in proportion to the fur- 
 nace, as a fufficient fpace ought always to be al- 
 lowed for the paffage of the air between the 
 Tides of the furnace and the veflel. The retort 
 A in the figure is too fmall for the fize of the 
 furnace, yet I find it more eafy to point out the 
 error than to correct it. The intention of the 
 dome is to oblige the flame and heat to furround 
 and (trike back or reverberate upon every part 
 of the retort, whence the furnace gets the name 
 of reverberatory. Without this circumftance 
 the retort v/ould only be heated in its bottom, 
 the vapours raifed from the contained Tub (la nee 
 would condenfe in the upper part, and a conti- 
 nual cohabitation would take place without any 
 thing palling over into the receiver ; but, by 
 means of the dome, the retort is equally heated 
 in every part, arid the vapours being forced out, 
 can only condenfe in the neck of the retort, or 
 in the recipient. 
 
 To prevent the bottom of the retort from be 
 ing either heated or coolled too fuddeniy, it is 
 fometimes placed in a fmali fand-bath of baked 
 day, (landing upon the crofs bars of the fur- 
 nace. Likewife* in many operations, the retorts 
 are coated over with lutes, fome of which are 
 intended to preferve them from the too fudden 
 influence of heat or of cold, while others are for 
 fuftaining the glafs, or forming a kind of fecond 
 3 N retort, 
 
460 
 
 ELEMENTS 
 
 retort, which fupports the glafs one during ope- 
 rations wherein the ftrength of the fire might 
 foften it. The former is made of brick-clay 
 with a little cow’s hair beat up alongft with it, 
 into a pafie or mortar, and fpread over the glafs 
 or (tone retorts. The latter h made of pure 
 clay and pounded flone-ware mixed together, 
 and ufed in the fame manner. This dries and 
 hardens by the fire, fo as to form a true fupple- 
 mentary retort capable of retaining the mate- 
 rials, if the glafs retort below fhould crack or 
 foften. But, in experiments which are intend- 
 ed for collecting gafies, this lute, being porous, 
 is of no manner of ufe. 
 
 In a great many experiments wherein very 
 violent fire is not required, the reverberatory 
 furnace may be ufed as a melting one, by leav- 
 ing out the piece called the laboratory, and 
 placing the dome immediately upon the fire- 
 place, as reprefented PL XIII. Fig. 3. The fur- 
 nace reprefented in Fig. 4. is very convenient 
 for fufions ; it is compofed of the fire-place and 
 aih-hole ABD, without a door, and having a 
 hole E, which receives the muzzle of a pair of 
 bellows ftrongiy luted on, and the dome ABGH, 
 which ought to be rather lower than is repre- 
 fented in the figure. This furnace is not ca- 
 pable of producing a very ftrong heat, but is 
 fufficient for ordinary operations, and may be 
 readily moved to any part of the laboratory 
 
 where 
 

 OF CHEMISTRY. 467 
 
 where it is wanted. Though thefe particular 
 furnaces are very convenient, every laboratory 
 mull: be provided with a forge furnace, having 
 a good pair of bellows, or, what is more necef- 
 fary, a powerful melting furnace. I ihall de- 
 fcribe the one I ufe, with the principles upon 
 which it is conftrudled. 
 
 The air circulates in a furnace m confequence 
 of being heated in its paffage through the burn- 
 ing coals ; it -dilates, and, becoming lighter than 
 the furrounding air, is forced to rife upwards 
 by the preffure of the lateral columns of air^ 
 and is replaced by frefh air from all fides, efpe- 
 cially from below. This circulation of air even 
 takes place when coals are burnt in a common 
 chaffing diffi ; but we can readily conceive, 
 that, in a furnace open on all fides, the mafs of 
 air which paffes, all other circumltances being 
 equal, cannot be fo great as when it is obliged 
 to pafs through a furnace in the ffiape of a hol- 
 low tower, like moft of the chemical furnaces* 
 and confequentiy, that the com bullion muff be 
 more rapid in a furnace of this latter con- 
 ftruftion. Suppofe, for inflance, the furnace 
 ABCDEF open above, and filled with burning 
 coals, the force with which the air palfes through 
 the coals will be in proportion to the difference 
 between the fpecific gravity of two columns 
 equal to AC, the one of cold air without, and 
 the other of heated air within the furnace. 
 
 There 
 
468 
 
 ELEMENTS 
 
 There muft be fome heated air above the open- 
 ing AB, and the fuperior levity of this ought 
 likewife to oe taken into confideration ; but, as 
 this portion* is continually coolled and carried 
 oft' by the external air, it cannot produce any 
 great effeft. 
 
 But, if we add to this furnace a large hollow 
 tube GHAB of the fame diameter, which pre- 
 ferves the air which has been heated by the 
 burning coals from being coolled and difperfed 
 by the furrounding air, the difference of fpecific 
 gravity which caufes the circulation will then be 
 between two columns equal to GC. Hence, if 
 GC be three times the length of AC, the cir- 
 culation will have treble force. This is upon 
 the fuppofition that the air in GHCD is as 
 much heated as what is contained in ABCD, 
 which is not ftricily the cafe, becaufe the heat 
 muft decreafe between AB and GH ; but, as 
 the air in GHAB is much warmer than the ex- 
 ternal air, it follows, that e e addition of the 
 tube muft increafe the rapidity of the ftream of 
 air, that a larger quantity muft pafs through 
 the coals, and confequentiy that a greater de- 
 gree of combuftion muft take place. 
 
 We muft not, however, conclude from thefe 
 principles, that the length of this tube ought to 
 be indefinitely prolonged ; for, fmce the heat of 
 the air gradually diminifines in paffmg from AB 
 X o GH, even from the contaft of the Tides of the 
 
 tube, 
 
G F CHEMISTRY. 463 
 
 tube, if the tube were prolonged to a certain 
 degree, we would at laft come to a point where 
 the fpecific gravity of the included air would be 
 equal to the air without ; and,* in this cafe, as 
 the cool air would no longer tend to rife up- 
 wards, it would become a gravitating mafs, re- 
 filling the afcenfion of the air below. Befides, 
 as this air, which has ferved for combuftion, is 
 necelfarily mixed with carbonic acid gas, which 
 is confiderably heavier than common air, if the 
 tube were made long enough, the air might at 
 laft approach fo near to the temperature of the 
 external air as even to gravitate downwards ; 
 hence we muft conclude, that the length of the 
 tube added to a furnace muft have fome limit 
 beyond which it weakens, inftead of ftrengthen- 
 ing the force of the fire. 
 
 From thefe refleftions it follows, that the firft 
 foot of tube added to a furnace produces more 
 effect than the fixth, and the fixth more than 
 the tenth ; but we have no data to afcertain at 
 what height we ought to ftop. This limit of 
 ufeful addition is fo much the farther in propor- 
 tion as the materials of the tube are weaker con- 
 ductors of heat, becaufe the air will thereby be 
 fo much lefs coolled ; hence baked earth is 
 much to be preferred to plate iron. It would 
 be even of confequence to make the tube double, 
 and to fill the interval with rammed charcoal, 
 which is one of the worft condu&ors of heat 
 
 known $ 
 
 ^ ' 
 
* 7 * 
 
 E L E M E N T S 
 
 known ; by this the refrigeration of the air wrd 
 be retarded, and the rapidity of the dream of 
 air confequently increafed ; ahd, by this means, 
 the tube may be made fo much the longer. 
 
 As the fire place is the hotted part of a fur- 
 nace, and the part where the air is mod dilated 
 in its paffage, this part ought to be made with a 
 confiderable widening or belly. This is the 
 more neceffary, as it is intended to contain the 
 charcoal and crucible, as well as for the palfage 
 of the air which fupports, or rather produces 
 the combuftion ; hence we only allow the inter- 
 ftices between the coals for the palfage of the 
 air. 
 
 From thefe principles my melting furnace is 
 condru&ed, which 1 believe is at lead equal in 
 power to any hitherto made, though 1 by no 
 means pretend that it poffelfes the greated pof- 
 fible intenfity that can be produced in chemical 
 furnaces. The augmentation of the volume of 
 air produced during its padage through a melt- 
 ing furnace not being hitherto afcertained from 
 exper ‘meat, we are dill unacquainted with the 
 proportions which fliould' exid between the in- 
 fen or and fuperior apertures, and the abfolute 
 fize of which thefe openings Ihould be made is 
 Fill lefs underdood ; hence data are wanting 
 by which to proceed upon principle, and we 
 can only acccmplifh the end in view by repeat- 
 ed trials*. 
 
 This 
 
OF CHEMISTRY. 473; 
 
 This furnace, which, according to the above 
 Rated rules, is in form of an eliptical fpheroid, 
 is reprefented PI. XIII. Fig. 6. ABCD ; it is cut 
 off at the two ends by two plains, which pafs, 
 perpendicular to the axis, through the foci of 
 the elipfe. From this fhape it is capable of con- 
 taining a confiderable quantity of charcoal., 
 while it leaves fufficient fpace in the intervals 
 for the paffage of the air. That no obftacle 
 may oppofe the free accefs of external air, it is 
 perfe&ly open below, after the model of Mr 
 Macquer’s melting furnace, and Rands upon an 
 iron tripod. The grate is made of flat bars fefc 
 on edge, and with confiderable interftices. To 
 the upper part is added a chimney, or tube, of 
 baked earth, ABFG, about eighteen feet long* 
 and almoft half the diameter of the furnace* 
 Though this furnace produces a greater heat 
 than any hitherto employed by chemifts, it is 
 Rill fufceptible of being confiderably increafed 
 in power by the means already mentioned, the 
 principal of which is to render the tube as bad 
 a condu&or of heat as poffible, by making it 
 double, and filling the interval with rammed 
 charcoal. 
 
 When it is required to know if lead contains 
 any mixture of gold or filver, it is heated in a 
 ftrong fire in capfules of calcined bones, which 
 are called cuppels. The lead is oxydated, be- 
 comes vitrified, and finks into- the fubftaneeof 
 
 the. 
 
47 2 
 
 ELEMENTS 
 
 the cuppel, while the gold or filver, being in- 
 capable of oxydation, remain pure. As lead 
 will not oxydate without free accefs of air, this 
 operation cannot be performed in a crucible 
 placed in the middle of the burning coals of a 
 furnace, becaufe the internal air, being moftly 
 already reduced by the combuftion into azotic 
 and carbonic acid gas, is no longer fit for the 
 oxydation of metals. It was therefore neceflary 
 to contrive a particular apparatus, in which the 
 metal fhould be at the fame time expofed to the 
 influence of violent heat, and defended from 
 contad with air rendered incombuftible by its 
 paffage through burning coals. The furnace 
 intended for anfwering this double purpofe is 
 called the cuppeiiing or efiay furnace. It is 
 ufually made of a fquare form, as reprefented 
 PI. XIII. Fig. 8. and io. having an afh-hole 
 AABB, a fire-place BBCC, a laboratory CCDD, 
 and a dome DDEE. The muffle or fmall oven 
 of baked earth GH, Fig. 9. being placed in the 
 laboratory of the furnace upon crofs bars of iron* 
 is adjufted to the opening GG, and luted with 
 clay foftened in water. The cuppels are placed 
 in this oven or muffle, and charcoal is convey- 
 ed into the furnace through the openings of the 
 dome and fire-place. The external air enters 
 through the openings of the afh-hole for fup- 
 porting the combuftion, and efcapes by the fu- 
 perior opening or chimney at EE $ and air is 
 
 admitted 
 
OF CHEMISTRY. 
 
 47: 
 
 admitted through the door of the muffle GG 
 for oxydating the contained metal. 
 
 Very little refledion is fufficient to difcover 
 the erroneous principles upon which this fur- 
 nace is conftru&ed. When the opening GG is 
 fhut, the oxydation is produced flowly, and with 
 difficulty, for want of air to carry it on ; and, 
 when this hole is open, the ftream of cold air 
 which is then admitted fixes the metal, and ob- 
 ftrucis the procefs. Thefe inconveniencies may 
 be eafily remedied, by conftrutting the muffle 
 and furnace in fuch a manner that a ftream of 
 frefh external air fhould always' play upon the 
 fuiface of the metal, and this air inould be 
 made to pafs through a pipe of clay kept con- 
 tinually red hot by the fire of the furnace. By 
 this means the infide of the muffle will never be 
 cooiled, and proceffes will be fmilhed in a few 
 rr inutes, which at prdent require a confiderable 
 ipace of time. 
 
 Mr Sage remedies thefe inconveniencies in a 
 different manner ; he places the cuppei contain- 
 ing lead, alloy ea with gold or filver, amongfl 
 the charcoal of an ordinary furnace, and cover- 
 ۥ by a fmall porcelain muffle; when the whole 
 is efficiently heated, he direfls the blaft of a 
 coalmen pair of hand-bellows upon the fuiface 
 of the metal, and completes the cuppellation in 
 this way with great eafe and exattnefs. 
 
 o O 
 
 SEC T. 
 
474 
 
 ELEMENTS 
 
 SECT. Hi. 
 
 V 
 
 Of increqfmg the Affion of Fire, by ufing Oxygen 
 Gas inflead of Atmofpheric Air . 
 
 By means of large burning glaffes, fuch as 
 thofe of Tchirnaufen and Mr de Trudaine, a 
 degree of heat is obtained fomewhat greater 
 than has hitherto been produced in chemical 
 furnaces, or even in the ovens of furnaces ufed 
 for baking hard porcelain. But thefe inflru- 
 ments are extremely expenfive, and do not even 
 produce heat fufficient to melt crude platina ; 
 fo that their advantages are by no means fuffi- 
 cient to compenfate for the difficulty of pro- 
 curing, and even of ufing them. Concave mir- 
 rors produce fomewhat more effeft than burn- 
 ing glaffes of the fame diameter, as is proved by 
 the experiments of Meffrs Macquer and Beaume 
 with the fpeculum of the Abbe Bouriot ; but, 
 as the direction of the refle&ed rays is neceffa- 
 rily from below upwards, the fubftance to be 
 operated upon muff be placed in the air with- 
 out any fupport, which renders mod chemical 
 experiments impoffible to be performed with 
 this inftrument. 
 
 For 
 
OF CHEMISTRY. 
 
 475 
 
 For thefe reafons, I firft endeavoured to em- 
 ploy oxygen gas for combuftion, by filling large 
 bladders with* it, and making it pafs through a 
 tube capable of being fliut by a ftop-cock \ and 
 in this way I fucceeded in caufing it to fupport 
 the combuftion of lighted charcoal. The in- 
 tenfity of the heat produced, even in my firft 
 attempt, was fo great as readily to melt a fmal! 
 quantity of crude platina. To the fuccefs of 
 this attempt is owing the idea of the gazome- 
 ter, defcribed p. 308. et feq . which I fubftituted 
 Snftcad of the bladders ; and, as we can give 
 the oxygen gas any neceflary degree of prefiure, 
 we can with this inftrument keep up a conti- 
 nued ftream, and give it even a very confider- 
 able force. 
 
 The only apparatus neceftary for experiments 
 of this kind confifts of a fmall table ABCD, 
 PI. XII. Fig. 15. with a hole F, through which 
 pafies a tube of copper or filver, ending in a 
 very fmall opening at G, and capable of being 
 opened or fhut by the ftop-cock H. This tube 
 is continued below the table at l m n 0 , and is 
 conne&ed with the interior cavity of the gazome- 
 ter. When we mean to operate, a hole of a few 
 lines deep muft be made with a chizel in a piece 
 of charcoal, into which the fubftance to be treat- 
 ed is laid ; the charcoal is fet on fire by means 
 of a candle and blow-pipe, after which it is ex- 
 po fed 
 
476 ELEMENTS 
 
 \ 
 
 pofed to a rapid ftream of oxygen gas from the 
 extremity G of the tube FG. 
 
 This manner of operating can* only be ufed 
 with fuch bodies as can be placed, without in- 
 convenience, in .contaCt with charcoal, fuch as 
 metals, fimple earths, &c. But, for bodies 
 whcfe dements have affinity to charcoal, and 
 which are confequently decompofed by that 
 fubflance, fuch as fulphats, phofphats, and 
 mofl of the neutral falts, metallic glafles, ena- 
 mels, &c. we muft ufe a lamp, and make the 
 ftreatn of oxygen gas pafs through its flame. 
 For this purpofe, we ufe the elbowed blow-pipe 
 ST, inflead of the bent one FG, employed with 
 charcoal. The heat produced in this fecond 
 manner is by no means fo intenfe as in the for- 
 mer way, and is very difficultly made to melt 
 platina. In this manner of operating with the 
 lamp, the fubftances are placed in cuppels of 
 calcined bones, or little cups of porcelain, or 
 even in metallic difhes. If thefe lafl are fuffi- 
 ciently large, they do not melt, becaufe, metals 
 being good conductors of heat, the caloric 
 fpreads rapidly through the whole mafs, fo that 
 none of its parts are very much heated. 
 
 In the Memoirs of the Academy for 1782, 
 p. 476. and for 1783, p. 573. the feries of ex- 
 periments I have made with this apparatus may 
 be feen at large. The following are fome of 
 the principal relults. 
 
 I • Rock 
 
OF CHEMISTRY, 
 
 477 
 
 r. Rock criftal, or pure filicious earth, is in- 
 , fufible, but becomes capable of being foftened 
 or fufed when mixed with other fubftances. 
 
 2. Lime, magnefia, and barytes, are infu- 
 [ fible, either when alone, or when combined 
 ii together - 9 but, efpecially lime, they aflift the 
 
 fufion of every other body. 
 
 3. Argiil, or pure bafe of alum, is completely 
 fufible per fe into a very hard opake vitreous 
 fubftance, which fcratches glafs like the preci- 
 ous (tones. 
 
 4. All the compound earths and ftones are 
 readily fufed into a brownifh giafs. 
 
 5. All the faline fubftances, even fixed alkali, 
 are volatilized in a few feconds. 
 
 6. Gold, filver, and probably platina, are 
 (lowly volatilized without any particular pheno- 
 menon. 
 
 7. All other metallic fubftances, except mer- 
 cury, become oxydated, though placed upon 
 charcoal, and burn with different coloured 
 flames, and at laft diflipate altogether. 
 
 8. The metallic oxyds likewife all burn 
 with flames. This feems to form a diftindtive 
 charadter for thefe fubftances, and even leads 
 me to believe, as was fufpedted by Bergman, 
 that barytes is a metallic oxyd, though we 
 have not hitherto been able to obtain the metal 
 in its pure or reguline ftate. 
 
 9. Some 
 
ELEMENTS 
 
 47 8 
 
 9. Some of the precious Hones, as rubies, 
 are capable of being foftened and foldered to- 
 gether, without injuring their colour, or even 
 diminifhing their weights. The hyacinth, tho’ 
 almoft equally fixed with the ruby, lofes its co- 
 lour very readily. The Saxon and Brafilian to- 
 paz, and the Brafilian ruby, lofe their colour 
 very quickly, and lofe about a fifth of their 
 weight, leaving a white earth, refembling white 
 quartz, or unglazed china. The emerald, chry. 
 foiite, and garnet, are almoft inftanriy melted 
 into an opake and coloured glafs. 
 
 10. The diamond prefents a property pecu- 
 liar to itfelf ; it burns in the fame manner with 
 combuftihle bodies, and is entirely difiipated. 
 
 There is yet another manner of employing 
 oxygen gas for confiderably increafing the force 
 of fire, by ufing it to blow a furnace. Mr A- 
 chard firft conceived this idea ; but the procefs 
 he employed, by which he thought to dephlo- 
 cifticate, as it is called, atmofphetic air, or to 
 deprive it of azotic gas, is abfolutely unfatif- 
 faftory. I propofe to conftruft a very fimple 
 furnace, for this purpofe, of very refractory 
 earth, fimilar to the one reprefented PI. XIII. 
 Tig. 4. but fmaller in all its dimenfions. It 
 is to have two openings, as at E, through one 
 of which the nozle of a pair of bellows is to 
 pafs, by which the heat is to be railed as high 
 a<> pofiible with common air ; after which, the 
 
 ftream 
 
OF CHEMISTRY. 
 
 479 
 
 ftream of common air from the bellows being 
 fuddenly ftopt, oxygen gas is to be admit- 
 ted by a tube, at the other opening, commu- 
 nicating with a gazometer having the pref- 
 fure of four or five inches of water. I can in 
 this manner unite the oxygen gas from feverai 
 gazometers, fo as to make eight or nine cubi- 
 cal feet of gas pafs through the furnace ; and 
 in this way I expert to produce a heat greatly 
 more intenfe than any hitherto known. The 
 upper orifice of the furnace muft be carefully 
 made of confiderable dimenfions, that the ca- 
 loric produced may have free iflue, left the too 
 fudden expanfion of that highly elaftic fluid 
 Ihould produce a dangerous explofion. 
 
 FINIS. 
 

 
 
 
 
 
 
 
 
 
 
 
 
/‘i. An: 
 
i i 
 
 •: 
 
 
 
 
 
 
 

 
 
 ■ 
 
 
 
 ' 
 
 ■ 
 
 
 
 
 
 
 
 
 . 
 
 . 
 
 
 
 
 
 
 ■ 
 
 
 
J'i atjc h 
 

 Pi-.ITE.KZ. 
 


 
■ 
 
APPENDIX. 
 
 I 
 
 No. I. 
 
 Table for Converting Lines , or Twelfth Parts of 
 an Inch , and Fractions of Lines , into Decimal 
 Fractions of the Inch • 
 
 Twelfth Parts 
 
 Decimal 
 
 
 Decimal 
 
 of a Line. 
 
 Fra&ions. 
 
 Lines. 
 
 Fractions. 
 
 I 
 
 0.00694 
 
 1 
 
 0.08333 
 
 2 
 
 O.OI389 
 
 2 
 
 0.16667 
 
 5 
 
 0.02083 
 
 3 
 
 0.25000 
 
 4 
 
 0.02778 
 
 4 
 
 o *33333 
 
 5 
 
 O.03472 
 
 5 
 
 0.41667 
 
 6 
 
 0.04167 
 
 6 
 
 0.50000 
 
 7 
 
 0.04861 
 
 7 
 
 °- 5 8 333 
 
 8 
 
 0.05556 
 
 8 
 
 O.66667 
 
 9 
 
 0.06250 
 
 9 
 
 O.75OOO 
 
 IO 
 
 0.06944 
 
 IO 
 
 °- 8 3333 
 
 1 1 
 
 0.07639 
 
 1 1 
 
 O.9I667 
 
 12 
 
 0.08333 
 
 - 
 
 1. 00000 
 
 
 3P 
 
 
 No. 
 
APPENDIX, 
 
 482 
 
 No. II. 
 
 Table for Converting the Obferved Height hs of 
 Water in the Jars of the Pneumato-Chemical 
 Apparatus , expreffed in Inches and Decimals , in* 
 to Correfponding Heighths of Mercury . 
 
 Water. 
 
 Mercury. 
 
 Water. 
 
 Mercury. 
 
 • I 
 
 .00737 
 
 4- 
 
 .29480 
 
 .2 
 
 .01474 
 
 5* 
 
 •3 68 5* 
 
 •3 
 
 • 0220 £ 
 
 6 . 
 
 .44221 
 
 
 •02948 
 
 7* 
 
 •5*59i 
 
 •5 
 
 .03685 
 
 8. 
 
 .5896 1 
 
 .6 
 
 .04422 
 
 9* 
 
 .66332 
 
 •7 
 
 •°5 1 59 
 
 10. 
 
 .73702 
 
 .8 
 
 .05896 
 
 1 1. 
 
 .81072 
 
 •9 
 
 .06033 
 
 12. 
 
 .88442 
 
 2. 
 
 .07370 
 
 *3- 
 
 .96812 
 
 2. 
 
 .14740 
 
 14. 
 
 I .04182 
 
 3- 
 
 .22010 
 
 IS* 
 
 I. 11525 
 
 No, 
 
APPENDIX. 483 
 
 No. III. 
 
 Table for Converting the Ounce Meafures ufed 
 by Dr Prieftly into French and Englijh Cubical 
 
 Inches • 
 
 
 
 Ounce 
 
 French cubi- 
 
 Englifh cubi- 
 
 meafures. 
 
 cal inches. 
 
 cal indies. 
 
 I 
 
 !- 5 6 7 
 
 I.898 
 
 2 
 
 3 ,I 34 
 
 3-796 
 
 3 
 
 4.701 
 
 5-694 
 
 4 
 
 6.268 
 
 7-592 
 
 5 
 
 7-835 
 
 9 - 49 ° 
 
 6 
 
 9.402 
 
 11.388 
 
 7 
 
 IO.969 
 
 13.286 
 
 8 
 
 12.536 
 
 15.184 
 
 9 
 
 14.103 
 
 17.082 
 
 10 
 
 15.670 
 
 I8.980 
 
 20 
 
 3 *- 34 ° 
 
 37.960 
 
 3 © 
 
 47.010 
 
 56.94O 
 
 40 
 
 62.680 
 
 75 . 92 0 
 
 50 
 
 7 8 - 35 0 
 
 94.900 
 
 60 
 
 94.020 
 
 I I3.88Q 
 
 70 
 
 IO9.69O 
 
 I 32.860 
 
 80 
 
 I25.36O 
 
 I5I.84O 
 
 90 
 
 141.030 
 
 i 7 o. 8 :'o 
 
 100 
 
 I56.7OO 
 
 189.800 
 
 1000 
 
 I567 OOO 
 
 1898.000 
 
 Ns, 
 
494 appendix; 
 
 No- IV. Additional. 
 
 Table for Reducing the Degrees of Reaumeur r s 
 Thermometer into its correfponding Degrees of 
 Fahrenheit's Scale . 
 
 R. F. R. F. 
 
 0=32 
 
 21 = 79.25 
 
 1=34.25 
 
 22= 81.5 
 
 2 = 3 6 -5 
 
 23= 8 3-75 
 
 3 = 38.75 
 
 24= 86 
 
 4=41 
 
 25= 88.25 
 
 5 = 43* 2 5 
 
 26= 90.5 
 
 < 5 = 45-5 
 
 27= 92.75 
 
 r-' 
 
 11 
 
 28= 95 
 
 8 = 50 
 
 29= 97.25 
 
 9 = 52.25 
 
 30= 99.5 
 
 10 = 54.5 
 
 31 = 101.75 
 
 11 =56.75 
 
 32=104 
 
 12=59 
 
 33 = 106.25 
 
 13=61.25 
 
 34=108.5 
 
 14=63.; 
 
 35 = 110.75 
 
 1 J=^S -75 
 
 36=113 
 
 l6 = 68 
 
 37=115.25 
 
 17 = 70.25 
 
 38=117.5 
 
 * 8 = 72-5 
 
 39=119.75 
 
 19=74.75- 
 
 40=122 
 
 20=77 
 
 
 R. E. 
 
 R. F. 
 
 41 = 124.25 
 
 61 = 169.25 
 
 42=126.5 
 
 62 = 171.5 
 
 43=128.75 
 
 ^3 = I 73 ° 7 S 
 
 44 = 13 * 
 
 64 = 176. 
 
 45 = * 33-25 
 
 65 = 178.25 
 
 46 =i 35-5 
 
 66=180.5 
 
 47=137.75 
 
 67 = 182.75 
 
 00 
 
 II 
 
 *-« 
 
 42- 
 
 O 
 
 68 = 185 
 
 49=142.25 
 
 69=187.25 
 
 50=144.5 
 
 70 = 189.5 
 
 51 = 146.75 
 
 71 = 19!. 75 
 
 52=149 
 
 72=194- 
 
 53=151.25 
 
 73=1962; 
 
 54=153-5 
 
 74=198.5 
 
 55 = 155-75 
 
 75=200.75. 
 
 56=158 
 
 76=203 
 
 57= 160.25 
 
 77=205.25 
 
 58=162.5 
 
 78 = 207.5 
 
 59= 164.75 
 
 79=209.75 
 
 60= 167 
 
 80=212 
 
 Note — Any degree, either higher or lower, than 
 what is contained in the above Table, may be at any 
 time converted, by remembering that one degree of 
 Reaumeur’s fcale is equal to 2.25 0 of Fahrenheit ; or 
 it may be done without the Table by the following for- 
 mula, i^~4-32=;F ; that is, multiply the degree of 
 4 
 
 Reaumeur by 9, divide the product by 4, to the quo- 
 tient add 32, and the fum is the degree of Fahrenheit 
 — E, 
 
appendix. 
 
 
 No. V. Additional. 
 
 Rules for converting French Weights and 
 Meafures into correfpondent Englijh Denomina- 
 tions *. 
 
 § i • Weights . 
 
 The Paris pound, poids de mark of Charles 
 magne, contains 9216 Paris grains ; it is divided 
 into 16 ounces, each ounce into 8 gros, and 
 each gros into 72 grains. It is equal to 7561 
 Englifh Troy grains. 
 
 The Englifh Troy pound of 12 ounces con- 
 tains 5760 Englifh Troy grains, and is equal 
 to 7021 Paris grains. 
 
 The Englifh averdupois pound of 16 ounces 
 contains 7000 Englifh Troy grains, and is equal 
 to 8538 Paris grains. 
 
 To reduce Paris grs. to Englifh Troy 
 
 grs. divide by ...» ~ 
 
 To reduce Englifh Troy grs. to Pa- r 21 9 
 ris grs . multiply by . . J 
 
 To reduce Paris ounces to Englifh "j 
 Troy, divide by ... * 
 
 To reduce Englifh Troy ounces to r 1,01 -' 73-4 
 Paris, multiply by . j 
 
 Or 
 
 * For the materials of this Article the Tranllatos 
 is indebted to Profeffor Robertfom 
 
APPENDIX. 
 
 485 
 
 Or the converfion may be made by means 
 of the following Tables. 
 
 I. To reduce French to Englijh Troy Weight a 
 
 The Paris pound = 7561 
 
 The ounce = 472.5625 (Englifh* 
 
 The gros = 59*0703 f Troy. 
 
 The grain = .8 1 94 J Grains. 
 
 II. To Reduce Englifh Troy to Paris Weight . 
 
 The Englifh Troy pound? 
 
 of 12 ounces 3 ^ 
 
 The Troy ounce = 585.0830 Paris 
 
 The dram of 60 grs. = 73^353 r 
 
 The penny weight, or? grains, 
 
 denier, or 24 grs. 3 y J 
 
 The fcruple, of 20 grs. = 24.3784 
 
 III. To Reduce EngUJJo Averdupois to Paris 
 Weight » 
 
 The averdupois pound of ^ ^ 
 
 16 ounces, or 7000 >=8538. ^ Paris 
 
 Troy grains* ) F grains. 
 
 The ounce - = 533*6250^) 
 
 § 2. 
 
APPENDIX. 
 
 487 
 
 § 2. Long and Cubical Meafures* 
 To reduce Paris feet or inches into 
 
 Englifh, multiply by - ^ 
 
 Englifh feet or inches into Paris, C 
 divide by ^ 
 
 To reduce Paris cubic feet or inch- . 
 
 es to Englifh, multiply by - 
 Englifh cubic feet or inches to Pa- C 
 ris, divide by - - ^ 
 
 Or by means of the following tables : 
 
 1.065977 
 
 1.211278 
 
 IV. To Reduce Paris Long Meafure to Englifh . 
 
 The 
 
 1: 
 
 Paris royal foot of ? 
 1 inches - 3 
 
 = 12.7977 
 
 The 
 
 inch 
 
 = 1.0659 !> 
 
 The 
 
 line, or of an inch 
 
 = .0888 
 
 The 
 
 ~ T of a line 
 
 = .0074^ 
 
 i 
 
 V. 
 
 To Reduce Englijh Long Meafure to 
 
 The 
 
 Englifh foot =11 
 
 .25961 
 
 1 
 
 The 
 
 inch - = 
 
 •93 8 3 1 
 
 1 
 
 The 
 
 \ of an inch = 
 
 - 1 1 73 
 
 |> Paris 
 
 The 
 
 1 _ _ 
 
 IO 
 
 .0938 ] 
 
 1 
 
 The 
 
 line, or T V = 
 
 .0782 J 
 
 1 
 
 F nglifb. 
 
 inches. 
 
 VI. 
 
VI. To Reduce French Cube Meafure to Englifh . 
 
 The Paris 
 
 The cubic 
 inch 
 
 cube foot=i. 2i 1278 2093.088384 
 
 = .000700 
 
 1. 21 1278 
 
 inches. 
 
 VII. To Reduce Englijh Cube Mect/ure to French . 
 
 The Paris pint contains 58.145 # Englifh cu- 
 bical inches, and the Englifh wine pint contains 
 •28.85 cubical inches; or, the Paris pint contains 
 
 * It is faid, Belidcr Archit . Hydrog . to contain 3 1 oz. 
 64 grs . of water, which makes it 58.075 Englifh inch- 
 es ; but, as there is confiderable uncertainty in the de- 
 terminations of the weight of the French cubical mea- 
 fure of water, owing to the uncertainty of the ftandards 
 made ufe of, it is better to abide by Mr Everard’s 
 meafure, which \Vas with the Exchequer ftandards, and 
 by the proportions of the Englifti and French foot, as 
 eftablifhed by the French Academy and Royal Society. 
 
 The Englifh cube foot, 
 or 1728 cubical inches 
 The cubical inch 
 The cube tenth 
 
 .0008 ^ inches. 
 
 § 3. Meafure of Capacity. 
 
 2.01508 
 
APPENDIX. 489 
 
 2.01508 Englifh pints, and the Englifh pint con- 
 tains .49617 Paris pints ; hence, 
 
 To reduce the Paris pint to the Eng--^ 
 
 Iifh, multiply by - - f Q 
 
 To reduce the Englifh pint to thev 2 ‘ 0I ^° 
 Paris, divide by * - * 
 
 3 CL 
 
 No. 
 
 
49 ° 
 
 APPENDIX. 
 
 No. VI. 
 
 Table of the Weights of the different Gaffes > at 
 28 French inches , or 29.84 Englijh inches ba - 
 rometrical preffure , and at io° (54*5*) °f iem ~ 
 perature , expreffed in Englijh meafure and En- 
 glijh Troy weight . 
 
 Names of the Gaffes. 
 
 Weight of a 
 
 Weight of a 
 
 
 cubical inch. 
 
 cubical foot. 
 
 # 
 
 qrs. 
 
 oz. dr. qrs. 
 
 Atmofpheric air 
 
 .32112 
 
 1 > IJ 
 
 Azotic gas 
 
 .30064 
 
 * 0 39-5 
 
 Oxygen gas 
 
 .34211 
 
 1 1 5 1 
 
 Hydrogen gas 
 
 .02394 
 
 0 0 41.26 
 
 Carbonic acid gas 
 ♦ * 
 
 .44108 
 
 1 4 41 
 
 Nitrous gas 
 
 .37000 
 
 1 2 39 
 
 Ammoniacal gas 
 
 • i8 5»5 
 
 0 5 19.73 
 
 Sulphurous acid gas 
 
 .71580 
 
 2 4 38 
 
 
 
 No. 
 
 * Thefe Sve were afcertained by Mr 
 
 Lavoifier him- 
 
 felf. — L. 
 
 ** The laft three are inferted by Mr Lavoifier upon 
 the authority of Mr Kirwan.— E. 
 
APPENDIX 
 
 491 
 
 No. VII. 
 
 Tables of the Specific Gravities of different bodies . 
 § 1. Metallic Subfiances. 
 
 GOLD. 
 
 Pure gold of 24 carats melted but not 
 
 hammered . . . 19.2581 
 
 The fame hammered . . 19*3617 
 
 Gold of the Parifian ftandard, 22 carats 
 
 fine, not hammered * . 17.4863 
 
 The fame hammered . . 17.5894 
 
 Gold of the ftandard of French coin, 
 
 2 1~ £ carats fine, not hammered 17.4022 
 The fame coined . . 17.6474 
 
 Gold of the French trinket ltandard, 
 
 20 carats fine, not hammered . 15.7090 
 
 The fame hammered . . 15.7746 
 
 SILVER. 
 
 Pure or virgin filver, 24 deniers, not 
 
 hammered . . . 10.4743 
 
 The fame hammered . . 10.5107 
 
 Silver of the Paris ftandard, 1 1 deniers 
 
 10 grains fine, not hammered f 10.1752 
 The fame hammered . . 10.3765 
 
 Silver, 
 
 * The fame with Sterling, 
 f This is 10 grs. finer than Sterling. 
 
492 
 
 APPENDIX. 
 
 Silver, ftandard of French coin, iode- 
 niers 21 grains fine, not hammered 10.0476 
 The fame coined . . 10.4077 
 
 PLATINA. 
 
 Crude platina in grains 
 The fame, after being treated with mu- 
 riatic acid . . 
 
 Purified platina, not hammered • 
 
 The fame hammered 
 The fame drawn into wire 
 The fame paffed through rollers 
 
 15.6017 
 
 16.7521 
 
 19.5000 
 
 20.3366 
 
 21.0417 
 
 22.0690 
 
 COPPER AND BRASS. 
 
 Copper, not hammered . . 7.7880 
 
 The fame wire drawn . . 8.8785 
 
 Brafs, not hammered . . 8.39 58 
 
 The fame wire drawn . . 8.5441 
 
 IRON AND STEEL. 
 
 Caft iron . . . 7.2070 
 
 Bar iron, either fcrewed or not * 7.7880 
 
 Steel neither tempered nor fcrewed 7*8331 
 Steel fcrewed but not tempered . 7.8404 
 
 Steel tempered and fcrewed . 7.8180 
 
 Steel tempered and not fcrewed . 7.8163 
 
 T I N. 
 

 appendix. 
 
 493 
 
 T I N. 
 
 Pure tin from Cornwall melted and not 
 
 fcrewed 
 
 7.2914 
 
 The fame fcrewed 
 
 7.2994 
 
 Malacca tin, not fcrewed 
 
 7.2963 
 
 The fame fcrewed 
 
 7 - 3 o6 5 
 
 Molten lead 
 
 “•3523 
 
 Molten zinc 
 
 7.1908 
 
 Molten bifmuth • . 
 
 9.8227 
 
 Molten cobalt • • 
 
 7.8X19 
 
 Molten arfenic 
 
 5 - 7 6 33 
 
 Molten nickel . 
 
 7.807O 
 
 Molten antimony , . 
 
 6.7 021 
 
 Crude antimony 
 
 4.0643 
 
 Glafs of antimony . • 
 
 4.9464 
 
 Molybdena » 
 
 4-7385 
 
 Tungftein 
 
 6.0665 
 
 Mercury . . 
 
 13.5681 
 
 § 2. Precious Stones . 
 
 
 White Oriental diamond 
 
 3-5212 
 
 Rofe-coloured Oriental ditto 
 
 3 - 53 10 
 
 Oriental ruby , 
 
 4-2833 
 
 Spinell ditto • . . 
 
 3.7600 
 
 Balias ditto 
 
 3.6458 
 
 Brazilian ditto . 
 
 3-53 r » 
 
 Oriental topas 
 
 4.0106 
 
 
 Ditto 
 
494 
 
 APPENDIX. 
 
 Ditto Piftachio ditto 
 
 4.0615 
 
 Brafillian ditto 
 
 3-5365 
 
 Saxon topas 
 
 3.5640 
 
 Ditto white ditto 
 
 3-5535 
 
 Oriental faphir 
 
 3-9941 
 
 Ditto white ditto 
 
 3 - 99 ” 
 
 Saphir of Puy 
 
 4.O769 
 
 Ditto of Brafil 
 
 3 -* 3°7 
 
 Girafol • ... 
 
 4.0000 
 
 Ceylon jargon 
 
 4.4161 
 
 Hyacinth • . 
 
 3.6873 
 
 Vermillion 
 
 4.2299 
 
 Bohemian garnet . • 
 
 4» 1 888 
 
 Dodecahedral ditto 
 
 4.0627 
 
 Syrian ditto 
 
 4.0000 
 
 Volcanic ditto, with 24 fides 
 
 2.4684 
 
 Peruvian emerald 
 
 z -7755 
 
 Cryfolite of the jewellers 
 
 2.7821 
 
 Ditto of Brafil 
 
 2.6923 
 
 Beryl, or Oriental aqua marine • 
 
 3-5489 
 
 Occidental aqua marine 
 
 2.7227 
 
 § 3. Silicious Stones. 
 
 Pure rock criftal of Madagafcar 
 
 2.6530 
 
 Ditto of Brafil 
 
 2.6526 
 
 Ditto of Europe, or gelatinous . 
 
 2.6548 
 
 Criflallized quartz 
 
 2.6546 
 
 Amorphous ditto 
 
 2.6471 
 
 Oriental 
 
APPENDIX. 
 
 495 
 
 Oriental agate 
 
 2-5901 
 
 Agate onyx 
 
 2 - 6 375 
 
 Tranfparent calcedony 
 
 2.6640 
 
 Carnelian • 
 
 2.6137 
 
 Sardonyx 
 
 2.6o25 
 
 Prafe • • 
 
 2.5805 
 
 Onyx pebble 
 
 2.6644 
 
 Pebble of Rennes 
 
 2.6538 
 
 White jade . 
 
 2.9502 
 
 Green jade 
 
 2.9660 
 
 Red jafper 
 
 2.66l2 
 
 Brown ditto 
 
 2.69I I 
 
 Yellow ditto 
 
 2.7101 
 
 Violet ditto 
 
 2.7I I I 
 
 Gray ditto 
 
 2.764O 
 
 Jafponyx 
 
 2.8l6o 
 
 Black prifmatic hexahedral fchorl 
 
 3-3 8 5 2 
 
 Black fpary ditto 
 
 3-3 8 5 2 
 
 Black amorphous fchorl, called antique 
 
 
 bafaltes 
 
 2.9225 
 
 Paving (tone 
 
 2.4I58 
 
 Grind (tone 
 
 2.I429 
 
 Cutler’s (tone . . 
 
 2.III3 
 
 Fountainbleau (tone 
 
 2.5616 
 
 Scyth (lone of Auvergne 
 
 2.5638 
 
 Ditto of Lorrain 
 
 2.5298 
 
 Mill (tone 
 
 2-4835 
 
 White flint 
 
 2.5941 
 
 Blackifh ditto 
 
 2.5817 
 
 
 § 4- 
 
49 *> 
 
 APPENDIX. 
 
 § 4. Furious Stones, &c. 
 
 Opake green Italian Terpentine, or ga- 
 
 bro of the Florentines 
 
 . 2.4295 
 
 Coarfe Briancon chalk 
 
 . 3.7274 
 
 Spanifh chalk 
 
 2.7902 
 
 Foliated lapis ollaris of Dauphiny 
 
 . 2.7687 
 
 Ditto ditto from Sweden 
 
 • 2.8531 
 
 Mufcovy talc 
 
 2.7917 
 
 Black mica 
 
 2.9004 
 
 Common fchiftus or flate 
 
 2.6718 
 
 New flate 
 
 2-8535 
 
 White rafor hone 
 
 2.8763 
 
 Black and white hone 
 
 3 - l 3 " 
 
 Rhombic or Iceland criftal 
 
 2.7151 
 
 Pyramidal calcareous fpar 
 
 . 2.7141 
 
 Oriental or white antique alabafter 
 
 2.7302 
 
 Green Campan marble 
 
 2.7417 
 
 Red Campan marble . 4 
 
 2.7242 
 
 White Carara marble 
 
 2.7168 
 
 White Parian marble 
 
 2.8376 
 
 Various kinds of calcareous (tones } 
 
 from 1.3864 
 
 ufed in France for building. 3 
 
 to 2.3902 
 
 Heavy fpar 
 
 4.4300 
 
 White fluor 
 
 3 #I 555 
 
 Red ditto 
 
 3.1911 
 
 Green ditto 
 
 3* i8i 7 
 
 Blue ditto 
 
 3.1688 
 
 Violet ditto • 
 
 3 tl 757 
 
 
 Red 
 
APPENDIX. 
 
 49 ? 
 
 Red fcintilant zeolite from Edelfors 
 
 2.4868 
 
 White fcintilant zeolite 
 
 2.0739 
 
 Criftallized zeolite 
 
 2-0833 
 
 Black pitch {tone 
 
 2.0499 
 
 Yellow pitch {tone 
 
 2.0860 
 
 Red ditto 
 
 2.6695 
 
 Blacki{h ditto . • 
 
 2.3191 
 
 Red porphyry 
 
 2.7651 
 
 Ditto of Dauphiny 
 
 2.7033 
 
 Green ferpentine 
 
 2.8960 
 
 Black ditto of Dauphiny, called variolite 
 
 2-9339 
 
 Green ditto from Dauphiny 
 
 2.9883 
 
 Ophites 
 
 2.9722 
 
 Granitello 
 
 3.0626 
 
 Red Egyptian granite 
 
 2.6541 
 
 Beautiful red granite 
 
 2.7609 
 
 Granite of Girardmas 
 
 2-7 i6 3 
 
 Pumice {tone 
 
 .9145 
 
 Lapis obfidianus 
 
 2.3480 
 
 Pierre de Volvic 
 
 2.3205 
 
 Touch {tone 
 
 2-4153 
 
 Bafaltes from Giants Caufeway 
 
 2.8642 
 
 Ditto prifmatic from Auvergne 
 
 2.4153 
 
 Glafs gall 
 
 2.8548 
 
 Bottle glafs 
 
 2.7325 
 
 Green glafs 
 
 2.6423 
 
 White glafs 
 
 2.8922 
 
 St Gobin criftal 
 
 2.4882 
 
 Hint glafs 
 
 3 - 3 2 93 
 
 Borax glafs • 
 
 2.6070 
 
 3 R 
 
 Seves 
 
498 APPENDIX. 
 
 Seves porcelain . * • 
 
 2-1457 
 
 Limoges ditto . • 
 
 2.3410 
 
 China ditto • 
 
 2.3847 
 
 Native fulphur . . 
 
 2.0332 
 
 Melted fulphur 
 
 1.9907 
 
 Hard peat 
 
 I * 3 2 9 ° 
 
 Ambergreafe 
 
 .9263 
 
 Yellow tranfparent amber, . 
 
 1.0780 
 
 § 5. Liquids . 
 
 
 Diftiiled water 
 
 1. 0000 
 
 Rain water . 
 
 1. 0000 
 
 Filtered water of the Seine 
 
 1. 00015 
 
 Arcueil water 
 
 1.00046 
 
 Avray water 
 
 1.00043 
 
 Sea water . 
 
 1.0263 
 
 Water of the Dead Sea 
 
 1.2403 
 
 Burgundy jvine 
 
 • 99*5 
 
 Bourdeaux ditto 
 
 •9939 
 
 Malmfey Madeira 
 
 1.0382 
 
 Red beer 
 
 1-0338 
 
 White ditto 
 
 1. 0231 
 
 Cyder 
 
 1. 0181 
 
 Highly re&ified alkohol 
 
 .8293 
 
 Common fpirits of wine 
 
 .8371 
 
 Alkohol 
 
APPENDIX. 
 
 •499 
 
 Alkohol i5pts. water 1 part. 
 
 .8527 
 
 14 
 
 2 
 
 .8674 
 
 13 
 
 3 
 
 LO 
 
 OO 
 
 CO 
 
 • 
 
 12 
 
 4 
 
 .8947 
 
 1 1 
 
 5 
 
 •9075 
 
 10 
 
 6 
 
 •9199 
 
 9 
 
 7 
 
 •93*7 
 
 8 
 
 8 
 
 .9427 
 
 7 
 
 9 
 
 •95 1 9 
 
 6 
 
 10 
 
 •9594 
 
 5 
 
 1 1 
 
 .9674 
 
 4 
 
 12 
 
 • 6 733 
 
 0 
 
 o 
 
 *3 
 
 .9791 
 
 2 
 
 *4 
 
 .9852 
 
 I 
 
 *J 
 
 .9919 
 
 Sulphuric ether 
 
 • 
 
 •7394 
 
 Nitric ether 
 
 • 0 
 
 . .9088 
 
 Muriatic ether 
 
 • • 
 
 • *7298 
 
 Acetic ether 
 
 • 
 
 . .8664 
 
 Sulphuric acid 
 
 • • 
 
 • 1.8409 
 
 Nitric ditto , 
 
 • 
 
 I * 2 7 I 5 
 
 Muriatic ditto 
 
 • m 
 
 . 1.1940 
 
 Red acetous ditto 
 
 • • 
 
 . 1.0251 
 
 White acetous ditto 
 
 • • 
 
 . 1. 01 35 
 
 Diftilled ditto ditto 
 
 • 
 
 1.0095 
 
 Acetic ditto 
 
 * # 
 
 . 1.0626 
 
 Formic ditto 
 
 • • 
 
 . *9942 
 
 Solution of cauftic ammoniac, or vola- 
 til alkali fiuor * 
 
 .8970 
 
 Efiential 
 

 50c APPENDIX# 
 
 
 Effential or volatile oil of turpentine 
 
 .8697 
 
 Liquid turpentine 
 
 .9910 
 
 Volatile oil of lavender • 
 
 .8938 
 
 Volatile oil of cloves 
 
 1 -0363 
 
 Volatile oil of cinnamon • 
 
 1.0439 
 
 Oil of olives . . 
 
 •9*53 
 
 Oil of fweet almonds 
 
 .9170 
 
 Lintfeed oil 
 
 •9403 
 
 Oil of poppy feed 
 
 .9288 
 
 Oil of beech mail . . 
 
 .9^6 
 
 Whale oil .... 
 
 •9233 
 
 Womans milk 
 
 x.0203 
 
 Mares milk . 
 
 1.0346 
 
 Afs milk 
 
 I,(3 355 
 
 Goats milk 
 
 1.0341 
 
 Ewe milk 
 
 I.O4O9 
 
 Cows milk 
 
 1.0324 
 
 Cow whey . 
 
 I.OI93 
 
 Human urine .... 
 
 I. 0106 
 
 § 6. Refins and Gums 
 
 
 Common yellow or white rofm 
 
 1.0727 
 
 Arcanfon 
 
 1.0857 
 
 Galipot * 
 
 1.0819 
 
 Baras *••••• 
 
 1.0441 
 
 
 Sandarac 
 
 * ReOnous juices extra<5ied in France from the Pine. 
 Vide Bomard s Di£U 
 
Sandarac 
 
 1.0920 
 
 Maftic • 
 
 1.0742 
 
 Storax ' . . 
 
 1.1098 
 
 Opake copal . 
 
 1.1398 
 
 Tranfparent ditto 
 
 1.0452 
 
 Madagafcar ditto 
 
 1.0600 
 
 Chinefe ditto 
 
 1.0628 
 
 Elemi 
 
 1.0182 
 
 Oriental anime 
 
 1.0284 
 
 Occidental ditto 
 
 1.0426 
 
 Labdanum 
 
 1.1862 
 
 Ditto in tortis 
 
 2, 4933 
 
 Refin of guaiac 
 
 1.2289 
 
 Ditto of jallap .... 
 
 1.2185 
 
 Dragons blood 
 
 1.2045 
 
 Gum lac 
 
 1. 1390 
 
 Tacamahaca .... 
 
 1.0463 
 
 Benzoin 
 
 1.0924 
 
 Alouchi * 
 
 1.0604 
 
 Caragna f 
 
 1. 1244 
 
 Elaftic gum .... 
 
 •9335 
 
 Camphor . 
 
 .9887 
 
 Gum ammoniac - . . . 
 
 1.2071 
 
 Sagapenum .... 
 
 1.2008 
 
 Ivy 
 
 * Odoriferous gum from the tree which produces 
 the Cortex IVinteranus. Bomars , 
 
 f Refin of the tree called in Mexico Caragna, or 
 Tree of Madnefs. Ibid, 
 
502 
 
 APPENDIX, 
 
 Ivy gum * . . ' • . 
 
 1.2948 
 
 Gamboge 
 
 1.2216 
 
 Euphorbium 
 
 1. 1 244 
 
 Olibanum 
 
 1. 1732 
 
 Myrrh .... 
 
 1.3600 
 
 Bdellium 
 
 *-37*7 
 
 Aleppo Scamony 
 
 *•*354 
 
 Smyrna ditto 
 
 *•2743 
 
 Galbanum 
 
 1. 2120 
 
 Affafoetida 
 
 *•3*75 
 
 Sarcocolla 
 
 1.2684 
 
 Opoponax 
 
 1.6226 
 
 Cherry tree gum 
 
 1.4817 
 
 Gum Arabic 
 
 1-4523 
 
 Tragacanth 
 
 1.5161 
 
 Bafora gum . , 
 
 1.4346 
 
 Acajou gum f . 
 
 1.4456 
 
 Monbain gum J 
 
 1.4206 
 
 Infpiffated juke of liquorice . 
 
 1.7228 
 
 Acacia , 
 
 I, 5 I 53 
 
 Areca 
 
 *•4573 
 
 Terra Japonica .... 
 
 1.3980 
 
 Hepatic aloes 
 
 *•3586 
 
 Socotrine aloes 
 
 1-3795 
 
 Jnfpiffated juice of St John’s wort 
 
 1.5265 
 
 
 Opium 
 
 * Ex traded in Perfia and the warm countries from 
 Hedera terreftris — Bomare . 
 
 + From a Brafilian tree of this name. — Ibid . 
 
 t From a tree of this name. — Ibid* 
 
appendix. 
 
 5®i 
 
 ; 3 6S 
 
 Indigo • • * .7690 
 
 Arnotto . ’•595® 
 
 Yellow wax . • • -9 6 4 8 
 
 White ditto . • • *9 686 
 
 Ouarouchi ditto * .8970 
 
 Cacao butter . • • ,8 9 i6 
 
 Spermaceti • • • *9433 
 
 Beef fat • • ‘9 2 3 2 
 
 Veal fat • ... -934 2 
 
 Mutton fat 
 
 Tallow . *9419 
 
 Hoggs fat • -9368 
 
 Lard • 947 8 
 
 Butter • • • .9423 
 
 § 7. Woods • 
 
 Heart of oak 60 years old . • 1.1700 
 
 Cork . ... .2400 
 
 Elm trunk . • • .6710 
 
 Afh ditto * • • -S450 
 
 Beech . *^5 2 ° 
 
 Alder . • • ♦ .8000 
 
 Maple . • • *755° 
 
 Walnut , .6710 
 
 Willow * . • • -5 8 5° 
 
 Linden . • • .6040 
 
 Male 
 
 * The produce of the Tallow Tree of Guayana. Vide 
 Barnard's Did, 
 
$0 4 A P P I 
 
 Male fir 
 Female ditto 
 Poplar * 
 
 White Spanifh ditto 
 Apple tree 
 Pear tree 
 Quince tree 
 Medlar - # 
 
 Plumb tree 
 Olive wood 
 Cherry tree 
 Filbert tree 
 French box 
 Dutch ditto 
 Dutch yew 
 Spanifh ditto 
 Spanifh cyprefs 
 American cedar 
 Pomgranate tree 
 Spanifh mulberry tree 
 Lignum vitae 
 Orange tree • 
 
 N D I X. 
 
 .5500 
 
 • . .4980 
 
 - • -3 8 3° 
 
 • • -5 2 94 
 
 . . .7930 
 
 • . .66lO 
 
 . • . «7050 
 
 • o *944° 
 
 . . . *7850 
 
 . • .9270 
 
 .7150 
 
 • • .6000 
 
 » . .9120 
 
 • . 1.3280 
 
 • . .7880 
 
 • • ,8070 
 
 » • *6440 
 
 • . .5608 
 
 • 1.3540 
 
 . . .8970 
 
 • I -333° 
 
 • • *7°5° 
 
 No. 
 
 Note — The numbers in the above Table, if the De- 
 cimal point be carried three figures farther to the 
 right hand, nearly exprefs the abfolute weight of an 
 Englifh cube foot of each fubftance in averdupois 
 ounces. See No. VIII. of the Appendix. — E. 
 
appendix. 
 
 5°5 
 
 No. VIII. Additional. 
 
 Rules for Calculating the Abfolute Gravity in 
 Englijh Troy Weight of a Cubic Foot and Inch, 
 Englijh Meafure , of any Subjlance whofe Speci- 
 fic Gravity is known # . 
 
 In 1696, Mr Everard, balance-maker to the 
 Exchequer, weighed before the Commiffioners 
 of the Houfe of Commons 2145.6 cubical inch- 
 es, by the Exchequer ftandard foot, of diftilled 
 water, at the temperature of 55 0 of Fahren- 
 heit, and found it to weigh 1 1 3 1 oz. 14 dts. 
 Troy, of the Exchequer ftandard. The beam 
 turned with 6 grs. when loaded with 30 pounds 
 in each fcale. Hence, fuppofing the pound 
 averdupois to weigh 7000 grs. Troy, a cubic 
 foot of water weighs 62 ~ pounds averdupois, 
 or 1000 ounces averdupois, wanting 106 grains 
 Troy. And hence, if the fpecific gravity of 
 water be called 1000, the proportional fpecific 
 gravities of all other bodies will nearly exprefs 
 the number of averdupois ounces in a cubic 
 foot. Or more accurately, fuppofmg the fpeci- 
 fic gravity of water exprefied by 1. and of all 
 other bodies in proportional numbers, as the 
 3 S cubic 
 
 * The whole of this and the following article was 
 communicated to the Tranflator by Profe/Tor P v obinfon^ 
 
 — E. 
 
50 6 A P P E N D I X, 
 
 cubic foot of water weighs, at the above tem- 
 perature, exactly 437489.4 grains Troy, and 
 the cubic inch of water 253.175 grains, the 
 abfolute weight of a cubical foot or inch of 
 any body in Troy grains may be found by mul- 
 tiplying their fpecific gravity by either of the 
 above numbers refpedtively. 
 
 By Everard’s experiment, and the propor- 
 tions of the Englifh and French foot, as efta« 
 blifhed by the Royal Society and French Aca- 
 demy of Sciences, the following numbers are 
 afcertained. 
 
 Paris grains in a Paris cube foot of 
 
 water - = 645511 
 
 Englifh grains in a Paris cube foot 
 
 of water == 529922 
 
 Paris grains in an Englifh cube foot 
 
 of water - = 533 2 47 
 
 Englifh grains in an Englifh cube 
 
 foot of water - = 437489.4 
 
 Englifh grains in an Englifh cube 
 
 inch of water - - = 253.175 
 
 \ 
 
 By an experiment of pPicard with 
 the meafure and weight of the 
 Chatelet, the Paris cube foot of 
 water contains of Paris grains = 641326 
 By one of Du Hamel, made with 
 
 great care - - = 641376 
 
 By Homberg - = 641666 
 
 Thefe 
 
I 
 
 APPENDIX, 507 
 
 Thefe fhow fome uncertainty in meafures or 
 in weights ; but the above computation from 
 Everard’s experiment may be relied on, be- 
 caufe the companion of the foot of England 
 with that of France was made by the joint la- 
 bours of the Royal Society of London and the 
 French Academy of Sciences : It agrees like- 
 wife very nearly with the weight afligned by 
 Mr Lavoifier, 70 Paris pounds to the cubical 
 foot of water. 
 
 No. 
 
508 
 
 APPENDIX. 
 
 No. IX. 
 
 Tables for Converting Ounces , Drams , and 
 Grains , Tray, into Decimals of the Troy Pound 
 of 12 Ounces , £ /<?r Converting Decimals of 
 the Pound Troy into Ounces , ?sV. 
 
 I. fir Grains . 
 
 Grains 
 
 r= Pound. 
 
 Grains : 
 
 = Pound. 
 
 1 
 
 .0001736 
 
 loo 
 
 .0173611 
 
 2 
 
 .0003472 
 
 200 
 
 .0374222 
 
 3 
 
 .0005208 
 
 3 °° 
 
 .0520833 
 
 4 
 
 .0006944 
 
 400 
 
 .0694444 
 
 5 
 
 .0008681 
 
 5 00 
 
 .0868055 
 
 6 
 
 ✓ 
 
 .0010417 
 
 600 
 
 .1041666 
 
 7 
 
 .0012153 
 
 700 
 
 .1215277 
 
 8 
 
 .0013889 
 
 800 
 
 •1388888 
 
 9 
 
 .0015625 
 
 900 
 
 .1562499 
 
 10 
 
 .0017361 
 
 1000 
 
 .1736110 
 
 20 
 
 .0034722 
 
 2000 
 
 .3472220 
 
 3 ° 
 
 .0052083 
 
 3000 
 
 .520833° 
 
 40 
 
 ,0069444 
 
 4000 
 
 .6944440 
 
 5 ° 
 
 .0086806 
 
 5000 
 
 .8680550 
 
 60 
 
 .0104167 
 
 6000 
 
 1.0418660 
 
 70 
 
 .0121528 
 
 7000 
 
 1. 2152770 
 
 80 
 
 .0138889 
 
 8000 
 
 I.3888880 
 
 90 
 
 .0156250 
 
 9000 
 
 1.5624990 
 
 II. 
 
APPENDIX. 5°2 
 
 II. For Drams . 
 
 Drams = Pound. 
 
 I 
 
 .OIO4167 
 
 2 
 
 .0208333 
 
 3 
 
 .03125OO 
 
 4 
 
 .0416667 
 
 5 
 
 .0520833 
 
 6 
 
 .0625OOO 
 
 7 
 
 .0729167 
 
 8 
 
 •0833333 
 
 III. 
 
 Ounce:. 
 
 Ounces 
 
 = Pounds. 
 
 i 
 
 •0833333 
 
 a 
 
 .1666667 
 
 3 
 
 .2500000 
 
 4 
 
 •3333333 
 
 5 
 
 .4166667 
 
 6 
 
 .5000000 
 
 7 
 
 •5833333 
 
 8 
 
 .6666667 
 
 9 
 
 .7500000 
 
 IO 
 
 •8333333 
 
 ii 
 
 ,9166667 
 
 12 
 
 1. 0000000 
 
 IV, 
 
;io APPENDIX, 
 
 IV. Decimals of the Pound into Ounces, &e» 
 
 Tenth parts. Thoufandths. 
 
 lib . = 
 
 oz. dr. gr. 
 
 lib . as 
 
 grs. 
 
 O.I 
 
 1 r 36 
 
 0.006 
 
 34’56 
 
 0.2 
 
 2 3 12 
 
 0.007 
 
 40.32 
 
 °*3 
 
 3 4 48 
 
 0.008 
 
 46.08 
 
 0.4 
 
 4 6 24 
 
 O.OO9 
 
 51.84 
 
 0.5 
 
 6 0 0 
 
 Ten thoufandth parts . 
 
 0.6 
 
 7 1 3 6 
 
 0.0001 
 
 0.576 
 
 0.7 
 
 8 3 12 
 
 0.0002 
 
 1. 152 
 
 0.8 
 
 9 4 48 
 
 0.0003 
 
 I.728 
 
 0.9 
 
 10 6 24 
 
 0.0004 
 
 2.304 
 
 Hundredth parts . 
 
 0.0005 
 
 2.880 
 
 0.0 1 
 
 0 0 57.6 
 
 0.0006 
 
 3*456 
 
 0.02 
 
 0 1 55.2 
 
 0.0007 
 
 4.032 
 
 0.03 
 
 0 2 52.8 
 
 0.0008 
 
 4.608 
 
 0.04 
 
 0 3 50.4 
 
 0.0009 
 
 5*184 
 
 0.05 
 
 0 4 48.0 
 
 Hundred thoufandth 
 
 0.06 
 
 0 5 45.6 
 
 parts 4 
 
 
 0.07 
 
 0 6 43.2 
 
 0.00001 
 
 O.052 
 
 0.08 
 
 0 7 40.8 
 
 0.00002 
 
 0.1 15 
 
 0.09 
 
 0 3 38.4 
 
 0.00003 
 
 0.173 
 
 Thoufandths . 
 
 0.00004 
 
 0.230 
 
 0.001 
 
 0 0 5.76 
 
 0.00005 
 
 0.2S8 
 
 0.002 
 
 0 0 11.52 
 
 0.00006 
 
 0.346 
 
 0.003 
 
 0 0 17.28 
 
 0.00007 
 
 0.403 
 
 0.004 
 
 0 0 23.04 
 
 0.00008 
 
 0.461 
 
 0 
 
 b 
 
 0 
 
 0 0 28.80 
 
 0.00009 
 
 CO 
 
 6 
 
 No. 
 
appendix, 
 
 5 ir 
 
 No. X. 
 
 Table of the Englijh Cubical Inches and Deci- 
 mals correfponding to a determinate Troy Weight 
 of Dijlilled Water at the Temperature of 55% 
 calculated from Everard y s experiment . 
 
 For Grains . 
 
 Grs. Cubical inches. 
 
 1 = .0039 
 
 2 .0078 
 
 3 .01l8 
 
 4 *0157 
 
 5 * 01 97 
 
 6 .0236 
 
 7 •° 2 75 
 
 3 *0315 
 
 9 -°354 
 
 10 .0394 
 
 20 .0788 
 
 30 .1182 
 
 40 .1577 
 
 50 .1971 
 
 For Drams . 
 
 Drams. Cubical inches. 
 
 1 = .2365 
 
 2 .473 1 
 
 3 - 7°94 
 
 4 -9463 
 
 5 1.1829 
 
 6 1.4195 
 
 7 1.6561 
 
 Oz. 
 
 fir Ounces . 
 
 Cubical inches. 
 
 I 
 
 = I.8927 
 
 2 
 
 3-7855 
 
 3 
 
 5.6782 
 
 4 
 
 7.5710 
 
 5 
 
 9.4631 
 
 6 
 
 “• 35<>5 
 
 7 
 
 i 3- 2 493 
 
 8 
 
 15.1420 
 
 9 
 
 17.0748 
 
 10 
 
 18.9276 
 
 1 1 
 
 20.8204 
 
 Libs. 
 
 For Founds . 
 Cubical inches. 
 
 I = 
 
 = 22.7131 
 
 2 
 
 45.4263 
 
 3 
 
 68.1394 
 
 4 
 
 90.8525 
 
 5 
 
 1 *3-5657 
 
 6 
 
 136.278S 
 
 7 
 
 i 58 - 99‘9 
 
 8 
 
 I81.7O5I 
 
 9 
 
 2O4.4183 
 
 10 
 
 227.1314 
 
 50 
 
 1135.6574 
 
 100 
 
 2271.3148 
 
 1000 
 
 227I3.I488 
 
 THE END. 
 

 
 
 
 
 
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