46 ELEMENTS OF LABORATORY WORK 



fall in temperature of the water formed from the steam, which 

 must change from 100 to the final temperature of the mixture. 

 Thence the numerical value of the temperature-change, corre- 

 sponding with the condensation of a certain quantity of steam, 

 is obtained by subtracting, from the total numerical value of the 

 temperature-change in the water, the numerical value obtained 

 from the condensed steam falling from 100 to the final tem- 

 perature. The value for 1 gram is then calculated. 



The most accurate observations have shown the numerical 

 value for 1 gram of water at 100 converted into steam at 

 100 to be 536. This number 536 has, unfortunately, been 

 called the latent heat of steam ; and the number 80, the latent 

 heat of water. Corresponding changes occur when any liquid 

 passes to the state of gas. 



Table showing the Number of Grams of Water which would be 

 changed from 1 to C. by the Fusion of 1 gram of the 

 following Solids : 



Beeswax . . .97*22 



Lead . . . 5-37 



Ice . . . . 79-25 



Sulphur . . . 9-35 



Spermaceti . . 82'22 



Silver . . .21-07 



Tin . . . . 14-25 



Zinc , 28-13 



and by the Vaporisation of the following Liquids : 



Bromine . . . 15'6 



Ethyl alcohol . . 209 



Ethyl ether . . 91 



Mercury ... 62 



Sulphur (liquid) . 362 



Turpentine . . 69 



Water . . . 536 



The above numbers are also called the ' latent heats ' of 

 fusion and vaporisation. 



