and in the Condensation of Vapours. 419 



By expressing the mean result of these two experi- 

 ments in the way employed by Mr. Watt and others, I 

 shall say that 1040 degrees of heat (Fahrenheit) are 

 liberated in the condensation of steam, and that con- 

 sequently this very quantity of heat is employed and 

 rendered latent when the water, already at the tempera- 

 ture of boiling water, is changed into steam. 



The duration of each of these two experiments was 

 from ten to eleven minutes, and I had boiled the water 

 some time in the matrass (to drive out the air which it 

 contained) before I directed the steam from it into the 

 worm of the calorimeter. 



As the results of these experiments have been very 

 uniform, and as they agree very well with the later ex- 

 periments made by Mr. Watt with a view to determine 

 the same question, I have not thought it necessary to 

 repeat them. 



I have, besides, been very much occupied with the fol- 

 lowing branch of my inquiries. 



SECTION XI. Of the Quantity of Heat developed in the 

 Condensation of the Vapour of Alcohol. 



As chemists are not agreed as to the state of the ele- 

 ments of the water which exist in alcohol, I thought 

 that, by determining with precision the quantity of heat 



