GENERAL THEORY OF THE GENERA- 

 TION OF STEAM 



CHAPTER I. 

 HEAT 



The generation of steam from water depends upon 

 the expenditure of heat. It is well to understand 

 what is meant by the term heat. 



Heat is a form of energy. It is in fact a mode of 

 motion among the particles or molecules which com- 

 pose matter. If the molecules are moving or 

 vibrating back and forth among themselves, the 

 sensation of heat is produced. This term is only 

 relative ; what seems cold to one person is hot to 

 another; but if we start from a common basis we 

 may say that a high rate of vibration in the mole- 

 cules produces heat. A low rate produces a very 

 much less degree of heat, which we are used to 

 calling cold. Inasmuch as any body in motion is 

 capable of overcoming resistance, that is, doing work, 

 we say that it has kinetic energy; therefore, the mole- 

 cules which are vibrating to produce the effect called 

 heat possess this energy, and hence, we are right in 

 saying that "heat is a form of energy." 



In other words, the molecules of a heated body 



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