ature. Heat the water in A until it boils, and allow the 

 steam from it to pass into B for four or five minutes. Then 

 record the temperature of the water in B, and thus deter- 

 mine the increase in the temperature of the water. Remove 

 T\ weigh the water in B, and calculate the number of grams 

 which have been added to its contents by the condensation 

 of the steam. This 



will give the amount & T 



of steam which has 

 been condensed. 



The steam lost 

 some heat during 

 condensation. The 

 water formed by the 

 condensation like- 

 wise lost heat, be- 



FiG. 18. Steam from A condenses in B. 



cause its temperature 



was lowered from 100 to the final temperature of the 

 water in B. From the law of mixtures, it follows that the 

 total amount of heat gained by the cool water originally 

 in B must equal the heat lost by the steam during con- 

 densation plus the heat lost by the warm water in cooling 

 from 100 to the final temperature. 



Calculate the number of calories gained by the cool 

 water, and the number of calories lost by the warm 

 water. The difference between these must be the heat 

 lost by the steam during condensation. Since we know 

 the amount of steam that has been condensed, we can 

 calculate the number of calories lost by one gram of 

 steam during condensation. This is the Latent Heat of 

 Vaporization. 



How much heat is given up by 2000 gm. of steam in 



