236 THE POPULAR SCIENCE MONTHLY 



sense of the man on the street concerning these matters (and he has 

 a great deal) is involved in the second law of thermodynamics, which 

 is not a law of conservation at all. It is a law of waste. 



At this point of our discussion it is necessary to use the word 

 degeneration so as to express more or less tentatively the idea that every 

 sweeping process brings about a definite amount of degeneration, an 

 amount that can be expressed numerically just as one speaks of so 

 many pounds of sugar or so many yards of cloth. Thus a certain 

 amount of degeneration is brought about when a compressed gas escapes 

 through an orifice, a certain amount of degeneration is brought about 

 when heat flows from a region of high temperature to a region of low 

 temperature, a certain amount of degeneration is brought about when 

 work is converted into heat by friction or by the flow of an electric 

 current through a wire, and so on. 



In a simple sweep the degeneration lies wholly in the relation 

 between the initial and final states of the substance. This is neces- 

 sarily the case because no outside substance is affected in any way by 

 the sweep, no work is done on or by the substance which undergoes 

 the sweep and no heat is given to or taken from it. In a trailing 

 sweep the degeneration may lie partly in the relation between the 

 initial and final states of the substance which undergoes the sweep, 

 partly in the conversion of work into heat, and partly in the flow of 

 heat from a high temperature region to a low temperature region. 

 In a steady sweep, however, the substance which undergoes the sweep 

 remains entirely unchanged as the sweep progresses, and the degenera- 

 tion lies wholly in the conversion of work into heat, in the transfer of 

 heat from a region of high temperature to a region of low temperature, 

 or in both. Therefore the idea of thermodynamic degeneration as a 

 measurable quantity can be reached in the simplest possible manner 

 by a careful scrutiny of a steady sweep. 



Proposition (a). — The thermodynamic degeneration which is repre- 

 sented by the direct conversion of work into heat at a given tempera- 

 ture is proportional to the quantity of work so converted. Consider, 

 for example, a steady flow of electric current through a wire from 

 which the heat is abstracted so that the temperature remains constant. 

 This process is steady, that is to say, it remains unchanged during 

 successive intervals of time, and therefore any result of the process 

 must be proportional to the time which elapses, that is to say, the 

 amount of degeneration occurring in a given interval of time is pro- 

 portional to the time, but the amount of work which is degenerated 

 into heat is also proportional to the time. Therefore the amount of 

 degeneration is proportional to the amount of work converted into heat 

 at the given temperature. 



Proposition (&). — The thermodynamic degeneration which is rep- 



