Man in Nature 341 



power, already utilised to some extent, and likely to be 

 made use of increasingly, simply does work off the energy 

 of the Earth's rotation ( 103), and, although in a very 

 minute degree, its employment hastens the time when 

 Earth and Moon will have the same period of rotation. 

 Similarly, all processes now proudly being increased in 

 power and speed dissipate ever faster the wealth of poten- 

 tial energy that Nature lays up at an ever diminishing rate. 

 Wind and water power and the Earth's store of internal 

 heat are the only non-wasteful sources of work. Nothing 

 is given for nothing, and even the knowledge revealed by 

 the scientific study of Nature, that the power for effecting 

 these processes will not last for ever, has been dearly^ 

 bought. Since the true part played by energy has been 

 understood in fact, though possibly not in name, the 

 governments of all civilised nations have exerted themselves 

 to encourage the most economical processes of manufacture, 

 the most satisfactory systems of agriculture, the most 

 intelligent methods of sewage disposal, and particularly to 

 ensure the continuance, and if possible the increase, of the 

 forests of the world, on which its prosperity, and even its 

 habitability, largely depend. 



436. Man's Place in Nature. The grand distinction/I 

 between Man and other creatures is that he can take 

 advantage of his environment, so as to modify his develop- 

 ment in any desired direction. He need not, except wil- 

 fully, drift before the wind of natural changes, but can 

 sail close up to it like a well -handled ship. Man's 

 higher nature can, and in many cases does, completely 

 control his lower or animal existence. The sense of moral 

 duty overcomes even the first law of animal nature the 

 preservation of life ; it reverses the struggle for existence by 

 substituting the principle of self-sacrifice, on which the 

 stronger protects, instead of destroys, the weaker. Man, 

 when most truly human, or in the highest attained stage of 

 the evolution of civilisation, ceases to be in harmony 

 with the system of Nature in the sense true of the lower 

 animals 



