SECT. II.] 



PROPERTIES OF STEAM. 



53 



The result of the second experiment being compared by our formula, (note to 



art. 75,) we have 



42909 x 



o77 



from whence, deducting 212 on the supposition that the specific heat of steam is 

 equal to that of water, we have 1050 0> 5 for the constant quantity of heat for con- 

 version into steam. The very small difference between this and Count Rumford's 

 result, arises from the fractions neglected in reducing the French to English weights. 

 80. Count Rumford also made experiments on the quantity of heat developed 

 in the condensation of the vapour of alcohol : the results of these experiments were 

 less regular than those of the experiments made with water, as might have been 

 expected, but they were nevertheless sufficiently uniform to give the quantity of 

 heat with considerable certainty. 



The vapour which is extricated from spirit of wine, when boiled, varies a little 

 with the intensity of the fire used in boiling it ; he took care therefore to note the 

 time which was taken in every experiment, in order to be able to judge, by com- 

 paring the quantity of vapour condensed with the time employed to form it, of 

 the intensity of the heat employed to boil the liquid. In the following table will 

 be found the details and results of five experiments made on the same day, 

 (January 21, 1812,) with alcohol of different degrees of strength. The specific heat 

 of the calorimeter and the water it contained, was always equal to that of 42909 

 grains of water ; and the thermometer employed was that of Fahrenheit. 



1 Philosophical Mag. vol. xliii. p. 65. 



