439 



recent experiments of Brix, at 972°. The numbers, however, 

 are not strictly comparable. For, the heat evolved by the 

 steam is truly its latent heat, or is clue solely to its change of 

 state, while the caloric evolved by ammoniacal gas, or muriatic 

 acid gas, undoubtedly consists of two distinct parts, viz., of 

 the heat of compression of these gases, and of that due to the 

 chemical action exerted between them, supposed in the liquid 

 condition, and water. 



" Though I did not entertain any doubts as to the accu- 

 racy of the results just stated, it was obviously desirable to 

 resort to some experiments, if any such could be devised, by 

 which they could be tested ; and none appeared better suited 

 to the purpose, than to pass ammoniacal gas into liquid muria- 

 tic acid, and muriatic acid gas into liquid ammonia, and deter- 

 mine, by the means already explained, the heat developed in 

 each case. Such experiments were accordingly performed, care 

 being taken that the gas introduced did not in amount exceed 

 what would be necessary for saturating the opposite principle 

 contained in the liquid, and subjoined are the numbers to which 

 they have conducted : 



Heat of ammoniacal gas passed into liquid muriatic acid, 2523° 

 Heat of muriatic acid passed into liquid ammonia, . . 1527° 



Deducting from the former 940°, and from the latter 885°, the 

 remainders are 1583° and 642°. Now, according to Andrews 

 (Transactions, Royal Irish Academy, vol. xix. part 2), .129 of 

 a gramme of ammonia, in the form of aqua ammonise, in com- 

 bining with liquid muriatic acid, evolves sufficient heat to raise 

 31.09 grammes of water 5.58°, from which it is easy to calcu- 

 late that it would raise an equal weight of water 1344°. But 

 the heat evolved by equal weights of ammonia and muriatic 

 acid, in combining with each other, are obviously reciprocally 

 proportional to their atomic weights, so that, 1344 being the 



17 

 number for ammonia, 1344 X —r.-= = 626 will be the number 



O0.5 



