CHEMISTRY . 



171 



bitter, and chalybeate. Its temperature is uniformly 

 from 52 to 53 Fahr. The first effects of drinking 

 these waters are some drowsiness, and sometimes 

 headache, which ceases, however, even previously to 

 the bowels being opened. A moderate dose acts 

 promptly and decisively on the primes via, without, 

 however, producing any griping, or leaving languor 

 or iaintness after its operation. Population of town 

 and parish in 1831, 22,942. 



CHEMISTRY. By this name, the etymology of 

 which is uncertain, we understand the science which 

 teaches the nature of bodies, or rather the mutual 

 agencies of the elements of which they are composed, 

 with a view to determine the nature, proportions, and 

 mode of combination of these elements in all bodies. 

 Natural philosophy , or physics, examines the reciprocal 

 influence of matter in masses. Chemistry treats of 

 . the mutual action of the integrant parts. In the 

 former, the phenomena are produced by the general 

 attraction or repulsion of bodies ; in the latter, by 

 minute combination or decomposition. With our 

 present knowledge of matter and its laws, we can- 

 not separate physics entirely from chemistry: one 

 science cannot be studied without the other. Those 

 artisans who first discovered the means of melting, 

 combining, and moulding the metals ; those physi- 

 cians who first extracted vegetable substances from 

 plants, and observed their properties, were the first 

 chemists. Instead, however, of observing a philoso- 

 phical method in their examinations ; instead of pass- 

 ing from what was known to what was unknown, 

 early inquirers suffered themselves to be led astray 

 by astrological dreams, the fables of the philosopher's 

 stone, and a hundred other absurdities. See Alchymy. 



Until the year 1650, we find little worthy of notice 

 in the liistory of chemistry. Rhazis, Roger Bacon, 

 Arnaud de Villeneuve, Basilius Valentin, Paracelsus, 

 Agricola, &c., observed some of the properties of 

 iron, quicksilver, antimony, ammoniac, saltpetre. 

 They discovered sulphuric, nitric, and other acids ; 

 the mode of rectifying spirits, preparing opium, jalap, 

 &c., and of purifying the alkalies. Glauber was dis- 

 tinguished for the accuracy of his observations. He 

 endeavoured to improve certain instruments ; advised 

 operators not to throw away any residuum, in per- 

 forming experiments, as useless ; discovered the salt 

 which is called, from him, Glauber's salt, &c. Such 

 isolated discoveries, however, could not form a com- 

 plete science. Stahl appeared, and, although his 

 theory was unsatisfactory and entirely gratuitous, 

 and, as later observations have proved, erroneous, yet 

 he laid the foundations of the chemical school of Ber- 

 lin, which has produced a succession of eminent che- 

 mists. He was himself much indebted to the cele- 

 brated Becher, whose views he corrected and ex- 

 tended. He was sensible that the greater part of 

 chemical phenomena might depend on a general 

 cause, or, at least, on a few general principles, to 

 which all combinations must necessarily be referred. 

 He supposed that bodies contained a combustible ele- 

 ment, which inflammable bodies lost by being burned, 

 and which they could regain from other more inflam- 

 mable bodies. This element he called phlogiston. The 

 establishing of a hypothesis, which connected almost 

 all phenomena with each other, was an important 

 step. Boerliaave adopted Stahl's system, and contri- 

 buted much to its general diffusion. He is the founder 

 of philosophical chemistry, which he enriched with 

 numerous experiments, in regard to fire, the caloric 

 of light, &c. Although the principles on which 

 those philosophers proceeded were false, yet the 

 science was much advanced by their labours. It was 

 reserved for Black, Priestley, Cavendish, Lavoisier, 

 Bergmen, Schule, and Kirwan, to overturn Stahl's 

 system, and substitute the pneumatic or antiphlogis- ' 



tic chemistry, the best history of which is to be found 

 in Fourcroy's Philosophic Chimique, and his Systcme d*s 

 C&nnaissances Chimiques. As soon as the composi- 

 tion of the atmospheric air was made known by Priest- 

 ley, it was observed that combustible bodies, burning 

 hi contact with it, instead of losing one of their ele- 

 ments, absorbed one of the component parts of the 

 air, and were thus increased in weight. This com- 

 ponent part has received the name of oxygen, because 

 many of the combustible bodies are changed by its 

 absorption into acids. Oxygen now took the place 

 of phlogiston, and explained the difficulties which be- 

 set the phlogistic theory. To Black we are indebted 

 for the basis of our present knowledge of the theory 

 of heat. His experiments were repeated, extended, 

 and confirmed by Cavendish, who was the first to dis- 

 cover the composition of water, as also the properties 

 of carbonic acid gas and hydrogen. Light and unity 

 were introduced into chemistry by the new technical 

 nomenclature adopted in 1787, by the aid of which 

 all the individual facts are easily retained hi the me- 

 mory, since the name of each body is expressive 

 either of its composition, or of its characteristic pro- 

 perty. Twelve or fifteen terms have been found suf- 

 ficient for creating a methodical language, in which 

 there is no inexpressive term, and which, by chang- 

 ing the final syllables of certain names, indicates the 

 change which takes place hi the composition of the 

 bodies. Lavoisier, Fourcroy, Guyton de Morveau, 

 and Berthollet, were the authors of this felicitous in- 

 novation. The chemical terminology admits of no- 

 thing arbitrary, and is adapted not only to express, 

 known phenomena, but also any which may be here- 

 after discovered. It is the first example of a syste- 

 matic and analytic language. 



The commencement of the 19th century forms a 

 brilliant era hi the progress of chemistry. The gal- 

 vanic apparatus of Volta presented to the experimen- 

 ter an agent unequalled in the variety, extent, and 

 energy of its action upon common matter. With 

 this apparatus, Sir Humphrey Davy commenced a se- 

 ries of researches, which resulted in a greater modi- 

 fication of the science than it had ever before expe- 

 rienced. He proved that the fixed alkalies were com- 

 pounds of oxygen with metallic bases, and thus led 

 the way to the discovery of an analogous constitu- 

 tion in the alkaline earths. To the same individual 

 the science is principally indebted for the establish- 

 ment of the simple nature of chlorine, and for the 

 investigation of iodine. Electric chemistry had its 

 origin in the researches of this great man, in which 

 line of discovery he has been followed by Mr Fara- 

 day, who is at present carrying on a series of experi- 

 ments, that will, to all appearance, lead to the esta- 

 blishment of definite proportions in the electric pro- 

 perties of all the bodies in nature. The researches 

 of Sir H. Davy concerning the nature of flame, re- 

 sulting as they did hi the invention of the miner's 

 safety-lamp, afforded to mankind a demonstration of 

 the utility of philosophy in contributing to the im- 

 provement of the arts of life. 



But- that department of chemistry, which has of 

 late been most successfully investigated, relates to 

 the definite proportions in which bodies unite to form 

 the various chemical compounds. To establish the 

 conclusions which have been arrived at, a multitude 

 of exact analyses were requisite. These were accom- 

 plished principally through the labours of Wentzel, 

 Vanquelin, Richter, Dalton, Guy-Lussac, Thenard, 

 Berzelius, and Thomson; and have terminated hi 

 tlie establishment of the general truth, that, when 

 bodies combine chemiqally and intimately with each 

 other, they combine in determinate quantities ; and 

 that, when one body unites with another hi more 

 than one proportion, the ratio of the increase rna j be 



