156 EXPLOITATION OF PLANTS 
nations have harnessed them, and before these nations 
we should be helpless without our own energy- 
transformers. 
In a normal year, the forty millions or so of the 
population of the United Kingdom use, or waste, some- 
thing over 5,000,000,000,000,000 British thermal units 
in coal alone. But of this array of units of energy in 
coal which we destroy we have actually used but a frac- 
tion, for we waste ten at least for every unit put to 
useful -work. 
From mighty waterfalls (if we had them) we might 
get this number of units of mere energy, but that would 
not be the equivalerat of the wasted coal, for from a 
waterfall could be got none of the myriad other products 
which make coal the most essential of raw materials. 
Recent events have made us all realise how dependent 
we are for our home comfort on the coal supply; but 
some, perhaps, who were without coal, cherished them- 
selves with gas, coke or electricity, without realising 
that all three are the products of the manipulation of 
coal. Without exaggeration, one may say that coal is 
the very basis_of our civilisation, because not only our 
home-life depends on it, but its use is essential for the 
production of nearly every manufactured article : war- 
ships, ploughs, or babies’ feeding-bottles, the cloth we 
wear, the high explosives we use against the Germans, 
all are either the direct products of coal or the result of 
coal-stoked furnaces which drive machinery. Not only 
is coal the foundation upon which the edifice of our 
present civilisation is built, it is part of the superstruc- 
ture. Several hundred thousand organic compounds 
are obtained directly or indirectly from coal, the names 
