THE PROVIDENT USE OF COAL 325 



distilling coal at low temperatures we might obtain large 

 quantities of material suitable for such purposes, of higher 

 calorific value even than the petrol now used — far more than 

 is to be had from coal tar as now made. Heavier oils, suitable 

 probably for engines of the Diesel type, are also obtainable. 

 Such products would have a considerably higher fuel value 

 than coal. At no distant date, it may even be to the advantage 

 of all large users of coal first to coke it at a low temperature and 

 then to convert the coke into " producer-gas " — so as to separate 

 all by-products of value, as well as realise the full fuel-value of 

 the coal. 



Low-temperature coal tar is not suitable for colour-making, 

 as I have said. In the not-far-distant future, however, the tar 

 obtained from coke ovens will furnish more of the materials 

 needed by the colour-maker than is likely to be required. 

 Distinct uses must therefore be found for the constituents of 

 low-temperature tar. 



We are enforcing a variety of sanitary provisions, at the 

 present day. I see no reason why one more should not be 

 added — that of the sanitary use of coal, why pressure should 

 not be brought to bear on the public to minimise the produc- 

 tion of smoke and fog. But charity may well begin at home — 

 one or other of the municipalities which has charge of its 

 gas supply should set the example and secure powers to 

 control the fuel supply of its district. We need bold experi- 

 ment in this as in many other directions. 



H. E. A. 



