6 LIFE IN NATURE. 



revolutions. But the motion is the same throughout. 

 It is interrupted and stored up in the spring; it is 

 not altered. We may say, that the tense spring is 

 the unbent spring plus motion. It embodies the force 

 we have exerted. It is not the same thing as it was 

 in its relaxed state; it is more. And it can only 

 pass again into the unbent state by giving out the 

 force which has been thus put into it. 



Steam is an instance of a similar thing. Water, 

 in passing into vapour, absorbs or embodies no less 

 than 960 degrees of heat. Vapour is not the same 

 thing as water; it is more it is water plus heat. 

 Nor can it return into the state of water again, with- 

 out giving out all this heat. Vapour, therefore, in 

 respect to force, is like a bent spring, and water is 

 like the spring relaxed. 



And further, as a bent spring tends constantly to 

 relax, and will relax as soon as it is permitted, or as 

 soon as ever the force which keeps it bent is taken 

 away, so does vapour constantly tend to return to 

 the state of water. It seeks every opportunity, we 

 might say, of doing so, and of giving out its force. 

 Like the spring, it is endowed with a power of 



