CHAPTER V. 



SATURATED STEAM AND ITS 

 PROPERTIES. 



Temperature is not the only property of saturated 

 steam which changes with the pressure. Other char- 

 acteristics also change. These may be stated briefly 

 as follows : 



i. The amount of heat which is required to raise 

 a pound of water from 32 degrees, or freezing, to the 

 point at which it boils or steams at a given pressure. 

 That is expressed, of course, in the only term we have 

 to measure latent heat, in B. T. U., and is called the 



HEAT OF THE LIQUID. 



2. The amount of heat which is required to 

 change water at the temperature at which it boils into 

 steam of the same temperature. THIS is CALLED 



LATENT HEAT OF EVAPORIZATION, OR LATENT 



HEAT. This, too, is expressed in B. T. U. 



3. The total amount of heat required to change 

 a pound of water at 32 degrees to steam of the 

 required temperature and pressure. This is called 



the TOTAL HEAT OF EVAPORIZATION, or simply, 

 TOTAL HEAT. 



It is plain that the TOTAL HEAT is the sum of the 

 LATENT HEAT plus the HEAT OF THE LIQUID. 



4. The number of cubic feet occupied by a pound 



