JoLY — The Abundance of Life. 57 



niimbers of actions going on throngliout nature are attended by 

 dissipatory effects arising from the motions of proximate molecules, 

 friction, viscosity, and electrical effects, the last of these in turn 

 degrading into heat by the action, unknown in its nature, of 

 electrical friction. 



Thus, on ail sides, the energy which was once most probably 

 existent solely in the form of gravitational potential, is being dis- 

 sipated into unavailable forms. We must recognize dissipation as 

 one attendant on inanimate transfer of energy. 



But when we come to consider inanimate actions in relation to 

 time, or time-rate of change, we recognize a new feature in the 

 plienomena attending transfer of energy ; a feature which has 

 before now been observed upon, although not ^from the present 

 standpoint.^ It is seen, in short, that the attitude of inanimate 

 material systems is very generally, if not in all cases, retardative 

 of change — opposing it by effects generated by the primary action, 

 which may he called " secondary " for convenience. Further, it 

 will be seen that these secondary effects are those concerned in 

 bringing about the inevitable dissipation. Were they non- 

 existent, the events of the universe would be accelerated, but it 

 is hard to see that there would be any loss of availability in the 

 class of actions to which I allude. 



As example, let us endeavour to transfer gravitational potential 

 energy contained in a mass raised above the surface of the earth 

 into an elastic body, which we can put into compression by resting 

 the weight upon it. In this way work is done against elastic 

 force and stored as elastic potential energy. We may deal with 

 a metal spring, or with a mass of gas contained in a cylinder, 

 fitted with a piston upon which the weight may be placed. In 

 either case we find the effect of compression is to raise the tempe- 

 rature of the substance, thus causing its expansion or increased 

 resistance to the descent of the weight. And this resistance con- 

 tinues, with diminishing intensity, till all the heat generated is 

 dissipated into the surrounding medium. The secondary effect 

 tlms delays the final transfer of energy. 



Again, if we suppose the gas in the cylinder replaced by a 

 vapour in]a state of saturation the effect of increased pressure, as 



1 HelmLoltz, "Ice and Glaciers." Atkinson's collection of his "Popular 

 Lectures." First Series, p. 120. Quoted by Tate, " Heat," p. 311. 



