120 eV THE H E AT DEVELOPED IN COMBUSTION. 



Sect. II. Experiments made with spirit of wine, alcohol, and 

 sulphuric ether. 



As the component parts of these inflammable liquids may 

 Experiments be considered as well ascertained by the results of the excel- 

 with inHam- ] eilt investigation of Mr. de Saussure*, I undertook to exa- 

 iqui s. m j ne t hem for the second time, in order to discover what 

 quantities of heat are developed in their combustion. I had 

 begun this undertaking five years ago; but, after having 

 made a considerable number of experiments, I desisted from 

 it, on account of the great difficulties that occurred. As 

 soon, however, as I had found means of rendering my appa- 

 ratus more perfect, I formed the project of recommencing it. 

 Before I enter into the particulars of my experiments, L 



must say a few words respecting the difficulties that occurred 



Difficulties in . <* T u A * j c a 



them, to me > even a ' ter *■ nat ' mv new apparatus ; and or the means 



1 employed to surmount them. I even found myself exposed 



to dangers, which it is necessary for me to mention as a 



caution to those, who may undertake the same inquirv. 



and even dan- J . . _ . * 



ger. When I made the experiments with highly rectified alco- 



hol, and more particularly with ether, 1 found it very difficult 



tbtTliqirid to prevent a portion of these volatile liquids from escaping in 

 the state of vapour from the bulk of them remaining in the 

 lamp. I procured a small lamp, resembling in shape a small 



p/event it? round snuffbox, with a nozzle rising from the centre of the 

 circular plate, which closed it atop ; and on this plate was 

 fixed a small pan, to hold cold water, for keeping the nozzle 

 cool, and preventing the heat from being communicated to 

 the body of the lamp. But this precaution was not sufficient, 

 when I burned ether, as I found to my cost: for though the 

 pan was twice the diameter of the lamp, and filled with very 

 cold water, the water was so heated in a few minutes, that an 

 explosion took place from vapour of ether kindling in the air 

 ,p"^ e Q rous€X " with aflame that rose to the ceiling. Indeed it was near 

 setting the house on fire. 



Warned by this accident I procured a new lamp, much 

 smaller than the former, being only an inch in diameter and 



Another lamp aM( j three quarters of an inch deep ; and its nozzle, which 

 was only two lines in diameter, was three quarters of an inch 



• See Journal, vol. xxi, pgs. 222, 259, 321. 



high. 



