150 Heat extri-cated in Combuftion. [Book II. 



One pound of charcoal melted ninety-fix pounds, 

 eight ounces. 



One pound of hydrogen gas melted 295105. 9 ounces, 

 3* drams. 



As a concrete acid is formed by the combuftion of 

 phofphorus, it is probable that very little heat or ca- 

 loric remains in the acid, and, confequently, that the 

 above experiment gives us very nearly the whole quan- 

 tity of elementary fire contained in the oxygen gas. 



M. Lavoifier had found, by a former experiment, 

 that one pound of phofphorus abforbs one pound eight 

 ounces of oxygen during combuftion j and fince, by 

 the fame operation, one hundred pounds of ice are 

 melted, it follows, that the quantity of caloric con- 

 tained in one pound of oxygen gas is capable of melt- 

 ing 66 Ibs. 10 ounces, 5 drams, 24 grains of ice. By 

 the aid of this fimple contrivance, M. Lavoifier has 

 been able to afccrtain, with apparent accuracy, the 

 quantity of caloric difengaged in mod of the common 

 proceffes of combuftion *. 



* ' From the combuftion of phofphorus, as related in the fore- 

 going experiments, it appears, that one pound of phofphorus re- 

 quires i Ib. 8 oz. of oxygen gas for its combuftion, and that z Ibs. 

 9 oz. of concrete phofphoric acid are produced. 



' The quantity of caloric difengaged by the combuftion of one 

 pound of phofphorus, exprefled by the number of pounds of ice 

 melted during that operation, is 100.00000. 



The quantity diiengaged from each pound of oxygen, during 

 the combuftion of phofphorus, exprefled ,4n the fame manner, 

 is - - ... '- 66.66667. 



The quantity difengaged during the formation of one pound of 

 phofphoric acid, 40.00000. The quantity remaining in each 

 pound of phofp'.ioric acid - - - o'.ooooo *. 



* We rjere fuppofe the phofphoric acid not to contain any calo- 

 ric, which is not flnftly true ; but, as I have before obferved, the 

 quantity it really contains is probably very fmall, and we have not 

 given it a value, for want of a fufficient data to go upon. 



In 



