314 LAVOISIER. 



Mr. Watt or had formed it himself, he did, previous 

 to June, 1783, adopt and express the opinion that his 

 experiment showed " dephlogisticated air to be water 

 deprived of its phlogiston." Now this was, in the 

 language of the Stahl doctrine, holding that water was 

 formed by the union of phlogiston with dephlogisti- 

 cated air, was a calx, as it were of phlogiston. But 

 Mr. Watt's theory was, that phlogiston and inflam- 

 mable air are synonymous. Be this, however, as it 

 may, the conclusion contains the real doctrine of the 

 composition of water, how much disguised soever by 

 the language of the phlogistic theory ; and that con- 

 clusion was communicated, Sir C. Blagden says, " in 

 summer, 1783," to M. Lavoisier. His words are, 

 " that he gave last summer (1783) some account of 

 Mr. Cavendish's experiments to M. Lavoisier, as well 

 as of the conclusion drawn from them, that dephlogis- 

 ticated air is only water deprived of its phlogiston : 

 but at that time so far was M. Lavoisier from thinking 

 any such opinion warranted, that till he was prevailed 

 upon to repeat the experiment himself, he found some 

 difficulty in believing that nearly the whole of the two 

 airs could be converted into water."* 



This passage is in Mr. Cavendish's paper ; but it is 

 not in his own hand-writing, nor is it in the paper as 

 at first printed ; it is added in the hand- writing of Sir 

 C. Blagden, and is therefore that .gentleman's assertion 

 of what had passed at Paris the summer before. M. 

 Lavoisier states that it was in June Sir C. Blagden saw 

 him ; and also states that he was present when the ex- 

 periment on which the French claim to the discovery 

 rests, was performed by Messrs. Lavoisier and Laplace 

 before several Academicians on the 24th of June. He 

 adds the material fact, that Sir Charles informed the 



* In a letter of Blagden's, published in ' Crell's Annals,' in 1786, he 

 states having mentioned to Lavoisier also Mr. Watt's conclusions, which 

 he there admits had been drawn "about the same time" as Cavendish's. 

 Vol. I. for 1786. 



