in Cornlustion, and in the Condensation of VapoUrs. 437 



niv experiments, or to make others similar, ali the difficulties 

 which I had to surmount before discoverinsi the means of 

 governing the conibuslioii oi inflammable liquids which 

 are very volatile. 



As the apparatus which I used in mv experiments is now 

 well known, it will be easy to Follow their details, and ap- 

 preciate their results. 1 shall endeavour to describe them, 

 with precison, but at the same time as rapidly as possible. 



After laying in a stock of common spirits of wine and 

 alcohol of ditferent degrees of purity, I deterniintd with 

 the greatest care their specific gravity at the teniperature of 

 60- (Fahrenheit), lakina, that of the water at the same tem- 

 perature = 1000000. I made choice of this temperature, 

 in order to detennme afterwards with more facility the 

 quantities of water which each of these liquids ought to 

 contain, according to the tables which were formed from 

 the results of the experiments of M. Lowitz. 



By the following table we shall see the specific gravity 

 of each of these liquids, and the quantity of pure alco- 

 hol of Lowitz, and of water, which it contains. 



Such are the results of the experiments which were trade 

 to determine the quantities of heat which these liquids fur- 

 nish in their combustion. 



In three cxperimeiits made with spirits of wine, the 

 quantities of heat manifested were: 



In the first .... 53*260 pounds of water at the freezing 

 point, carried to ebidlition. 



Ill the second . . 51-727 potmds. 



And in the third 52-855 



Mean result . . . 52-614 pounds. 



As one pound of this liquid contains only 07798 pound 

 of alcohol regarded as pure by Lowitz, the other parts 

 = 0-2212 pound, being water only which docs not burn: 

 in order to sec how much water at the freezing point could 

 be boiled liy one pound of pure alcohol of Lowitz, we 

 have only to divide the quantity which is the measure of 

 the mean heat developed in the experiments with spirits of 

 wine, by the fraction which expresses the quantity of the 

 E c 3 alcohol 



