THE PROVIDENT USE OF COAL 319 



inflammable substances are given off which burn with a smol<;y 

 flame ; by first coking the coal at a low temperature, we may 

 remove and recover these and obtain a fuel which both takes 

 fire and burns as readily as coal and on the average gives a better 

 and hotter fire. By burning such soft coke in our towns we 

 might get rid of the smoke nuisance, if not entirely, to a very 

 large extent. In making such soft coke, we should separate 

 from the coal substances of considerable value for a variety of 

 purposes which are now wasted entirely. I am even prepared 

 to go so far as to urge that such a policy be made compulsory at 

 no distant date in our towns. 



The subject has been in my thoughts during the past thirty 

 years. In the early eighties I was led to pay much attention to 

 the by-products of the manufacture of gas from oil, as practised 

 by the various railway companies in making gas for compression 

 to be used as an illuminant in railway carriages — an industry 

 now somewhat in abeyance. I also studied the tars from the 

 Jameson coke oven — in which coal was coked in such a manner 

 that the volatile products were given off at a very low tempera- 

 ture compared with that prevailing in the gas retort. 



In a note communicated to the Iron and Steel Institute in 

 1885 I ventured to insist that we knew practically nothing of 

 what happens when coal is distilled or of the conditions most 

 favourable to the production of the most valuable constituents 

 of coal tar and that until we possessed accurate knowledge on 

 such points the coking of coal and the manufacture of gas from 

 coal could not be conducted scientifically. I urged that experi- 

 ments should be made. 



Nothing was done until the Coalite Company took the matter 

 in hand recently. Coalite is simply soft coke formed by heating 

 coal until all the volatile products which burn with a smoky 

 flame are given off. I have availed myself of the opportunity 

 which its manufacture affords to examine the products of the 

 distillation of coal at temperatures perhaps not exceeding 800° C. 

 The investigation is only in the early stage but I have already 

 learnt enough to convince me that the tar obtained, as indeed 

 was to be expected, is very different from ordinary gas-works 

 tar, which is clearly a mixture of the end-products of numerous 

 and complex changes undergone by the primary products of 

 decomposition of the coal substance at high temperatures in 

 contact with intensely heated carbon. The Coalite tar consists 



