10 SCIENCE AND LIFE 



and the martial spirit, which were once the essentials 

 of survival, whatever they may be to-day. The 

 progress of change spreading upwards throughout 

 society leads to some strange paradoxes. Official 

 constructive philosophy long since deteriorated in a 

 soil utterly exhausted by a monotonous alternation 

 of introspective and retrospective agriculture and the 

 bearing of a monotonous succession of the same 

 dwindling harvest. It alone remains sterile, whilst 

 all around, in the most unexpected places, the 

 fertilising influence of the new knowledge, won and 

 being won by the perfection of the extrospective or 

 experimental method, is producing a luxuriant, if 

 tangled, growth. 



THE ENERGY OF COAL. 



So far as the mere multiplication of the physical 

 capacity of the race is concerned, the shifting and 

 transport of loads, the hurling of projectiles or the 

 minimisation of animal strength, the social effects of 

 science are obvious enough. But these are but 

 special instances of a universal change, which the 

 modern doctrine of energy enables us to envisage 

 in its entirety. All life-processes demand for their 

 continuation and maintenance a continuous supply 

 of energy, which is derived from food. A modern 

 maxim might be, "Look after the energy and the 

 matter will look after itself." In metabolism, so far 

 as matter is concerned, there is a closed cycle. Men 

 feed on animals, and animals on plants. The plants 

 feed on the carbon-dioxide and other products of the 

 animal metabolism, reconverting them into food. 

 The net result is nil, or nearly so, as far as the 

 material changes are concerned. They cancel out. 

 But the one essential physical factor that makes the 

 process possible is the supply of energy as sunlight 



