Qf Mr. Colquhoun on the Life and Writings [Jan. 



the solution of metals in acids : — whence results so considerable 

 a quantity of inflammable air ? If the sole constituents of sul-^ 

 phuric acid be sulphur and oxygen, whence comes it that when 

 it is brought into contact with a metal, with the addition of a 

 little water, so large a quantity of inflammable air should be pro- 

 duced during their reaction ? This objection, which at first 

 appeared unanswerable, was soon converted into a proof of that 

 theory which it threatened to subvert, by Cavendish's great 

 discovery of the composition of water. He proved it to be no 

 longer an element, but formed it by combining its constituents, 

 oxygen and inflammable air. This experiment was eagerly laid 

 hold of by Lavoisier, and repeated by him and his associates in 

 1783. And now Lavoisier's theory was established by an 

 unbroken chain of reasoning from experiment, connecting the 

 double processes of synthesis and analysis in its support, such as 

 should have constrained all enlightened chemists to renounce 

 for ever the ancient system of error. 



This, however, was far from being the case : and the sketch 

 which has just been given of the fundamental principles of the 

 old and new systems of chemistry is necessary on two accounts 

 in a life of Berthollet. It is necessary in the first place to under- 

 stand the errors under which he laboured while yet he remained 

 a staunch adherent of the theory of Stahl ; and it is so in the 

 second, to explain the large share which his subsequent reason- 

 ings and discoveries had in elucidating and supporting the 

 theory of Lavoisier, after he became fairly convinced of its truth. 



The fii'st extant memoir of Berthollet (which appeared in the 

 Journal de Physique for 1776), the subject of which is Tartarous 

 Acid, seems never to have been laid before the Academy of 

 Sciences. The first which our chemist appears to have submit- 

 ted to that learned body, is an essay on Sulphurous Acid, read 

 in the end of the following year. It is the custom of the Aca- 

 demy, it may be here remarked, upon receiving any original 

 memoir, to appoint one or more of their members to examine 

 into its merits, and to report on them. Lavoisier was not unfre- 

 quently one of those who reported on Berthollet's earliest 

 memoirs, and they all furnish most striking proofs at once of the 

 extreme repugnance of the latter to adopt the doctrines of the 

 new theory, even when these seemed most necessary to him, 

 and of the great respect which the former showed even for the 

 errors of our chemist, whose genius from the first he fondly and 

 tenderly cherished. In this memoir on Sulphurous Acid, while 

 Berthollet is compelled to admit that sulphur during its combus- 

 tion unites with a portion of atmospheric air, he nevertheless, in 

 viewing its constitution, most wantonly encumbers and per- 

 plexes his explanations with an unsparing use of the phlogiston 

 of Stahl. Lavoisier regarded sulphur as a simple body, sulphu- 

 rous acid as a compound of that body with a certain dose of 



