CHEMISTRY. 



CHEMISTRY. 



philosophic*! nature ; and in hii investigations upon ponderebla ub- 

 Uooes he ha* entered the true path of experiment with caution* tops, 

 following juit analogic*, and measuring hypotheses by their liuiple 

 relation to facts." 



It is, however, matter of hiatory, and ought not to be suppressed, 

 that Lavoisier wai not content merely to employ the discoveries of 

 other*, even without acknowledgment, but that he made a distinct 

 claim to the discovery of oxygen, a claim which Dr. Priestley satis- 

 factorily refuted, by minting, what might hare been contradicted, but 

 which wa* not, that he had mentioned this gai and the mode of pro- 

 curing it at the table of M. Lavoiaier himself. He make* scarcely any, 

 if any, acknowledgment of the labour* of hi* predecessors, and his 

 friend* have claimed for him the discovery of nitrogen gas, previously 



described by Priestley and Rutherford. 

 Claude Louis Berthollet ( 



; (born in 1748, died in 1822) was the author 

 of more than eighty memoirs on chemical subjects. His earlier papers 

 on siilphurou* acid, ammonia, and the decomposition of nitre, were 

 published while he was yet a believer in the phlogistic theory, whirl i 

 he nalously defended, but afterwards renounced. One of his most 

 important contributions to chemistry was that of demonstrating, in 

 1 785, the nature and properties of the elements of ammonia. About 

 the same time he made his experiments on the dephlogisticated marine 

 acid of Scheele, which, from experiments well calculated to give rise to 

 the opinion, he supposed to be a compound of muriatic acid and oxy- 

 gen, and it was called oxygenised muriatic acid. These views, in 

 consequence chiefly of the experiments of Davy, have been shown to 

 be erroneous ; and this gas is now called chlorine, and is admitted to 

 have hitherto resisted all attempts at decompotiitioii. It was stated by 

 Scheele, in his experiments on this gaseous body, that, among other 

 properties which it possessed, was that of destroying vegetable colour- 

 ing matter. In consequence of this remark, Berthollet applied it to 

 the purpose of bleaching, in which it is now most extensively and 

 almost universally used. 



The ex|>eriinenta which Berthollet made on prussic acid and its 

 compounds advanced, but did not complete, our knowledge respecting 

 those bodies. In examining the properties of sulphuretted hydrogen, 

 he observed that it possessed acid properties ; it was not however by 

 the French chemists admitted to the class of acids, because it was 

 inconsistent with the theory just adopted, that all acids must contain 

 oxygen. Berthollet also discovered fulminating silver, and first 

 employed alcohol as a solvent for obtaining potash and soda in a 

 pure state. 



In 1803 Berthollet published a work entitled 'Chemical Statics,' 

 the object of which was to controvert the opinions of Bergman on 

 chemical affinity ; but although he pointed out some difficulties 

 attendant upon them, they wore by no means refuted. In this work 

 Berthollet also maintained the opinion that quantity may be made to 

 overcome the force of the chemical affinity existing between bodies. 

 There were, however, several points of the argument which he neg- 

 lected, or with which he was unacquainted ; indeed, at the period at 

 which he wrote, the doctrine of definite proportions had not been pro- 

 mulgated, a doctrine which will explain many of the apparent 

 anomalies that occurred to Berthollet. Indeed, in a discussion with 

 Proust in which the latter had decidedly the advantage, Berthollet 

 asserted that bodies were capable of uniting with each other in all 

 proportions. But whatever may have been the erroneous views of 

 Berthollet in some particular cases, chemistry is greatly indebted to 

 him for many valuable discoveries and minor details ; and the appli- 

 cation of the bleaching jmwer of chlorine is a practical scientific 

 improvement which has, for its extent and usefulness, scarcely been 

 surpassed. 



Louis Bernard Ouyton de Morveau was born at Dijon in 1787, and 

 died in 1816. Although the publications of this chemist were very 

 numerous, and contributed much to the extension of the science, yet 

 he was not the author of any very prominent discovery. His papers 

 are scattered through the ' Dijon Mdmoires,' 'Journal de Physique,' 

 and 'Annales de Chimie.' There are, however, some circumstances 

 connected with the history of chemistry in which his )>articipation 

 must not be overlooked. In 1787, in conjunction with Lavoisier, 

 Berthollet, and Fourcroy, he published a work in one volume 8vo, 

 entitled ' Methode de Nomenclature Chimique,' in which the important 

 improvements projected and nibsequently adopted ore detailed. In 

 1801 ho published a tract, ' Des Moyens de desinfecter 1'Air.' For thin 

 purpose be used various acids, and especially hydrochloric acid ; but he 

 afterwards adopted chlorine, which is now so generally used for the 

 same purpose. The application of these disinfectants was made in 

 1782, although the history of it was not given to the public till the 

 year above mentioned. He was the author of a considerable portion 

 of the chemical articles in the ' Kwydup&lie Muthodique ; ' and that 

 on ' Acid ' has been justly commended for its accuracy, both as to 

 experimental and historical details. [Oi'YTOX OB MUBVKAU, in Bioo. 

 Div.) 



Antoine Francois do Fourcroy was bom at Paris in 1755, and died in 

 This chemist wa* more celebrated as one of the first authors, 

 if nut the earliest, of a treatise on chemistry, and as a lecturer, than as 

 a promulgator of any very great discovery. His chemical work went 

 through several editions, and is in general written with perspicuity 

 and attention to the history of the science. Hi* ' Philosophy f 



Chemistry ' is also a work of considerable merit As a discoverer, he 

 is to be mentioned as having first shown that the salts of ammonia and 

 magnesia have a tendency to form double salts ; and he particularly 

 pointed out the ammoniaco-magnesian phosphate. He ascertained that 

 biliary calculi resemble spermaceti in their nature ; and he imagined 

 that muscular flesh is convertible into a fatty substance, which l>" 

 named adipocire. He published several papers in conjunction with 

 Vauquelin, but what belongs to each it is impossible to tell. It has 

 been supposed that the facts were principally ascertained by Vauquelin, 

 and the account of them written by Fourcroy. Among other papers, 

 they published one giving a method of obtaining baryta from the 

 nitrate by heat ; they discovered also the existence of phosphate of 

 magnesia in bones, and of phosphorus in the brain and in the melts 

 of fishes. 



It has been mentioned, that the analysis of precious stones had, 

 though imperfectly, been attempted by Bergman : this deportment !' 

 chemistry received vast accessions from the labours of Martin Henry 

 Klaproth, who was born at Wernigerode in 1743, and died in 1817. 

 This chemist introduced into the art of analysis more improvi 

 than we can even allow room to detail. The vast progress which If 

 made in the science will be fully estimated when it in known. 

 the time at which he commenced his labours the correct analysis of 

 scarcely any minerals was known, and that he analysed nearly two 

 hundred with so much accuracy that his results have been generally 

 confirmed, whilst the simplicity of his method of operation is greatly to 

 be commended. In 1789 he discovered a new metal in a mineral c dli-d 

 pechblende, to which he gave the name of uranium ; and in the same 

 year, in analysing the zircon, he found a new earth, which he c .11. .1 

 zirconia, and which has since been shown by Berzelius to be a metallic 

 oxide. In 1795 he found the same substance in the hyacinth : in thu 

 year he also found in the red schorl the some metallic oxide which 

 Gregor had previously met with and called menachine. Klaproth 

 named it titanium, and this appellation is now generally employed. 

 Apparently ignorant of the fact that Btrontia hod been previously 

 described as a peculiar earth, he in 1798 showed the difference 1" 

 it and baryta, they having been confounded in Germany up to that 

 time. In 1798 he gave an account of tellurium as a new metal, but it 

 had been before noticed by Miiller. In 1804 he described a new sub- 

 stance, which he called ochroita. Berzelius and Hisinger consider.^! it 

 a metallic oxide, and called the metal cerium. Besides these more 

 important contributions to science, he made many discoveries of 

 minor importance, which may be found in his ' Analyses,' of which 

 two volumes were published and translated into English. Beside* 

 mineralfi, there will bo found analyses of some mineral wat< 

 account of the effects produced by intense heat upon various mil 

 and the details of the methods of analysis, which are exti 

 valuable and instructive, both as to the nature and method of 

 employing various chemical reagents. 



M. Vauquelin was one of the most distinguished analyst* of th 

 sent century. He was born in Normandy, in what year we know not ; 

 but he died in 1829. His analyses were not confined to any particular 

 class of bodies, and he published more and ]>erhaps included a greater 

 variety in his operations than any other chemist ; his researches in- 

 cluded the three kingdoms of nature, but his greatest discoveries were 

 in the mineral. In the emerald and beryl he found a new earth, to 

 which, on account of the sweetness of the salts which it formal with 

 acids, he gave the name of glucina; but his discovery of chromium, in 

 the state of chromic acid, in the red lead of Siberia, was an era in 

 chemical history. Originally met with in a scarce and valuable mineral, 

 it has since been found in various parts of the earth combined with 

 iron, and in immense quantity ; it is largely employed for various uses; 

 in the state of oxide for giving a green to porcelain ; in that of acid, 

 combined with oxide of lead, it forms both a fine yellow .-mil orange 

 chromate, which is used in painting and calico printing. It would be 

 in vain to attempt an analysis of Vauquclin's various papers; th 

 chiefly to be found in the ' Annales de Chiiuii-.' ami will amply rc)y 

 perusal. He was also author of a work entitled, ' Manuel 1 1, 

 which he was particularly competent to write, not merely on account 

 of his great akill, but also as being assay-master of the mint. [VACy 

 in Bioo. Div.] 



Mr. Smithson Tennant was born in Yorkshire in 1761, and dic.l in 

 1814. In 1791 he made an experiment, which confirmed the jm vions 

 statement of Lavoisier as to the composition of carbonic acid. He 

 effected this by passing phosphorus through red-hot carbonate of lime, 

 and he found that the phosphorus was acidified at the expense of tin- 

 oxygen of the carbonic acid, and that while phosphoric acid was formed 

 charcoal was developed. In 1796 he heated the diamond with nitrate 

 of potash in a gold tube, and he found that the diamond, by combining 

 with the oxygen of the nitric acid, was converted into carbonic :icid, 

 ami this combined with the |K>tash of the decomposed nitrate to form 

 carbonate of potash. He observed in 1799 that certain limestones, on 

 account of the carbonate of magnesia which they contain, ore hurtful 

 to vegetation ; he examined the substance known by the name of 

 emery in 1802, and showed that it is a variety of corundum ; and in 

 1804 he discovered two new metals, viz., osmium and indium, in the 

 grains of native platinum. 



.I.Jm (joUliirh <tahn (born in 1746, in Sonili llclsingland. died iii 

 1818) was the pupil of Bergman. He was particularly skilled in the 



