246 COAL 



3. Brown coal, or Lignite (from the- Latin lignum, wood), 

 retains its woody texture and smell. It is of later formation 

 than the other varieties of coal, and at present is chiefly 

 useful for producing gas. 



With regard to coal it is important to remember that 

 a definite Quantity of it exists, and that every ton we burn 

 lessens that quantity. From time to time attempts have been 

 made to estimate how much coal still remains in the kingdom 

 In 1905 a Final Report was issued by the Royal Commission 

 on Coal Supplies. This is what they said : ' We have adopted 

 4,000 feet as the limit of practicable depth in working, and 

 one foot as the minimum workable thickness and ... we 

 estimate the quantity of coal in the Proved Coalfields of the 

 United Kingdom to be 100,914,668,167 tons. 



Probable duration of our Coal Supplies. In 1913 the output 

 of coal in the United Kingdom was 287 million tons. But 

 from year to year the output varies, and the Commissioners 

 say ' we hesitate to prophesy how long our coal resources are 

 likely to last ... we look forward to a time, not far distant, 

 when the rate of increase of output will be slower, to be 

 followed by a period of stationary output, and then a gradual 

 decline '- 1 

 POSSIBLE SUBSTITUTES. 



1. Petroleum. It is possible to use this instead of coal for 

 many purposes, see p. 264. 



2. Water-Power. The only part of the United Kingdom 

 in which we can look forward to a large development of water- 

 power is Scotland, and even there only a few places are 

 capable of developing powers of over 1,000 horse-power during 

 the whole year. 2 



Tides. There remain the tides. The rise and fall of the sea 

 all around our shores seems to offer an illimitable source of 



1 Final Report of tJie Royal Commission on Coal Supplies. 



2 'The water power of the Dominions, especially of Canada and New 

 Zealand, are great, and as they provide a cheap, convenient, cleanly, and 

 inexhaustible form of energy, their potentialities in respect of industrial 

 development are immense.' Dominions Royal Commission. 



