392 WATT. 



whole would be condensed." And he accounts for common 

 air and inflammable air, when burnt together, not producing 

 acid, by supposing that the heat produced is not sufficient. 

 He then says that these experiments, with the exception of 

 what relates to the acid, were made in the summer of 1781, 

 and mentioned to Dr. Priestley ; and adds, that " a friend of 

 his (Mr. Cavendish's), last summer (that is, 1783), gave some 

 account of them to M. Lavoisier, as well as of the conclu- 

 sion drawn from them, that dephlogisticated 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." The friend is 

 known to have been Dr., afterwards Sir Charles Blagden ; 

 and it is a remarkable circumstance, that this passage of Mr. 

 Cavendish's paper appears not to have been in it when ori- 

 ginally presented to the Royal Society ; for the paper is appa- 

 rently in Mr. Cavendish's hand, and the paragraph, p. 134, 

 135, is not found in it, but is added to it, and directed to be 

 inserted in that place. It is, moreover, not in Mr. Cavendish's 

 hand, but in Sir Charles Blagden's ; and, indeed, the latter 

 must have given him the information as to M. Lavoisier, 

 with whom it is not said that Mr. Cavendish had any corre- 

 spondence. The paper itself was read 15th January, 1784. 

 The volume was published about six months afterwards. 



M. Lavoisier's memoir (in the Mem. de I'Academie des 

 Sciences for 1781) had been read partly in November and 

 December 1783, and additions were afterwards made to it. It 

 was published in 1784. It contained M. Lavoisier's account 

 of his experiments in June 1783, at which, he says, Sir 

 Charles Blagden was present ; and it states that he told M. 

 Lavoisier of Mr. Cavendish having " already burnt inflamma- 

 ble air in close vessels, and obtained a very sensible quantity 

 of water." But he, M. Lavoisier, says nothing of Sir Charles 

 Blagden having also mentioned Mr. Cavendish's conclusion 

 from the experiment. He expressly states, that the weight of 

 the water was equal to that of the two airs burnt, unless the 

 heat and light which escape are ponderable, w hich he hold 



