On the Heat developed in Combustion, etc. 371 



At length, however, I have the satisfaction of an- 

 nouncing to the Class, that, after all my fruitless 

 attempts, I have discovered a very simple method of 

 measuring the heat manifested in combustion, and this 

 even with such precision as leaves nothing to be desired. 



That the Class may be the better able to judge of my 

 method of operating, and the reliance that may be 

 placed on the results of my experiments, I place my 

 apparatus before it. 



The principal part of this apparatus is a kind of 

 prismatic receiver, eight inches long, four inches and a 

 half broad, and four inches three quarters high,* formed 

 of very thin sheets of copper. This receiver, which well 

 deserves the name, already celebrated, of calorimeter ', is 

 furnished with a long neck, near one of its extremities, 

 three quarters of an inch in diameter, and three inches 

 high, intended to receive and support a mercurial ther- 

 mometer of a particular shape. The receiver has also 

 another neck, an inch in diameter and the same in 

 height, situate in the centre of its upper part, and closed 

 by a cork. 



Within this receiver, two lines above its flat bottom, 

 is a particular kind of worm, receiving all the products 

 of the combustion of the inflammable substances burned 

 in the experiments, and transmitting the heat manifested 

 in this combustion to a considerable body of water, 

 which is in the receiver. 



This worm, which is made of thin copper, occupies 

 and covers the whole bottom of the receiver, yet with- 

 out touching either its bottom or its sides. It is a flat 

 tube, an inch and a half broad at one end and an inch at 

 the other, and half an inch thick throughout. It is 



* French measure. 



