THE ENERGY OF COAL 11 



to the plant, which, unlike the animal, can utilise it 

 in this form for its life's work. 



Scientifically there is nothing peculiar about vital 

 energy, or about one form of available energy rather 

 than another. That is to say, if not yet, some time 

 in the future, the synthesis of food from the material 

 constituents and any form of available energy will 

 probably become possible. Historically, and till 

 quite recently, the energy of sunlight, apart from an 

 insignificant source in the tides, was the sole income 

 of energy available for the world, and the traditional 

 source by which, through the intermediary of plant 

 metabolism, both men and animals lived. Mankind 

 still lives solely on the energy derived from the sun, 

 but in addition to his former income, utilised as 

 before through the pursuit of agriculture, he has 

 secured the control of a handsome legacy of solar 

 energy, laid by in former times. He is living- on 

 an immensely more lavish scale than any of his 

 predecessors, not because he has had any great 

 increase in salary in the proper sense, not even 

 because he is, in the mass, somewhat more intelligent, 

 but because he is squandering an inheritance. The 

 plants which, alone of living forms, can utilise the 

 energy of sunlight, were at work for man ages before 

 the remotest likeness to his image had appeared 

 upon the world, and, even then, were laying the 

 foundations on which alone his present greatness 

 rests. Quite extraordinary physiographical conditions 

 must have prevailed, an alternate uplifting and 

 depressing of the bed of the ocean, time and again, 

 as one age succeeded another, when the luxuriant 

 forests of the carboniferous era flourished in the sun, 

 and then sank beneath the sea. In this fossilised 

 vegetation, preserved as coal, sandwiched between 

 alternate layers of shale, is conserved some tiny 

 fraction of the solar energy so prodigally radiated 



