1825.] of Claude-Louis BerthoUet. 7^ 



oxygen, and sulphuric acid as the same base united to a greater 

 proportion of the same air. BerthoUet, on the other hand, in 

 his view of the constitution of sulphur and its two acids, gives a 

 striking specimen of the old school of error driven to extremity, 

 and unable either to check the progress of experiment and know- 

 ledge, or to go on with it. Sulphur, says BerthoUet, is not a 

 simple body, but a compound one, and its constituents are phlo- 

 giston and a base ; sulphuric acid is a compound of phlogiston, 

 the same base, and vital air or oxygen gas ; and sulphurous acid 

 is the same base united to less vital air than exists in sulphuric 

 acid, and to less phlogiston than is found in sulphur. If this 

 complex explanation be deprived of the phlogiston, with so 

 large a dose of which it is combined, the exposition of the 

 nature of sulphur and its acids given by BerthoUet is not really 

 different from that of Lavoisier. At the same time it is difficult 

 to conceive how that chemist could preserve his patience at 

 seeing theories, otherwise so excellent, wholly spoiled, and 

 talents which might have been so usefully exerted, wholly frit- 

 tered away by the bigotted support of a system which every 

 day's experience made less and less defensible, and in defiance 

 of a simple yet just doctrine, of which he had several years before 

 developed the outlines, and had now nearly completed the 

 proofs. Yet, at this time, he stood single in the Academy, and 

 even BerthoUet, while he admits the Lavoisierian principle of 

 the presence of oxygen in these acids, cannot rest satisfied until 

 he confuses and perplexes every thing by superinducing the error 

 neous views of Stahl upon the plainest facts and the simplest 

 theory. 



It seems surprising too, that a man who thought so freely for 

 himself as BerthoUet's whole after life proves him to have done, 

 should so long have remained attached to the ill-founded system 

 of Phlogiston. Yet, independent of the force of prejudice, 

 which, once deep-seated, rules with most power the strongest 

 minds, it is no more than justice to BerthoUet to state, that he 

 himself, in a memoir, read to the Academy in the beginning of 

 1778, on the subject of Sulphuretted Hydrogen Gas, details the 

 experiments which became the foundation of a subsequent 

 material restriction of the theory of Lavoisier. Of course, even 

 if the conjecture of Cuvier be correct, that neither BerthoUet 

 nor Lavoisier at that time saw all the consequences resulting 

 from this experiment, yet as the former chemist, in a few years 

 a^'ter, resumed the subject, and was the first, by many a year, to 

 lay down this very Umitation of tlie doctrine of the latter, it is 

 fair to suppose that, even at this time, he must almost « son 

 Uiscii, have felt a powerful, and in this case a well-grounded 

 prejudice, against a leading part of the new system. 



it was unfortunately laid down by Lavoisier, as one of his 

 fundamental principles, that oxygen constitutes the sole princi- 



