108 



Kim me ridge clay and shale, locally known as Kimmeridge 

 coal, has recently yielded naphtha by distillation, and great promise 

 is foreshadowed for a successful re-working of the seams. British 

 paraffin and paraffin wax are distilled from bituminous shales 

 around Edinburgh. Our staple fuel is perhaps coal, which yields a 

 smoky and sullen atmosphere. It is interesting to compare the 

 cleanliness of Paris in this respect, where coke and charcoal are 

 largely used. The combustion of coal results in the production of 

 compounds, which have a distinct disintegrating effect upon 

 building stones, and concern is felt for many of our historic build- 

 ings in the Metropolis, whose walls are falling into decay owing 

 to continued action of various compounds produced. 



How long will our coal supply last? This has been a 

 poignant and debatable question for long, but it would appear that 

 owing to economy in consumption, to improvements 'n engineer- 

 ing, whereby electric power is being more largely used, and to the 

 introduction of other fuels, that our coal consumption has about 

 reached its maximum, and we may look for a decline in this 

 direction. Although this is so, it must be borne in mind that the 

 best varieties will be exhausted first, and, unlike other com- 

 modities, there is always a harvest, but only one seed time, and 

 that was long ago. 



(Read before the Geological Section, March 29th and April 12th, 1916). 

 ARBON occurs on the earth in a variety of compounds and 



^ in the free state. As carbon dioxide it is an essential con- 

 stituent of the atmosphere and forms the source not only of the 

 greater part of organic matter assimilated by plants of the present 

 day, but also of the vast stores of carbonaceous material locked 

 up as coal in sedimentary rocks. In combination with lime, 

 magnesia, and other bases it forms a considerable part of stratified 

 rocks, more especially of the limestones, chalks and marbles. 

 Carbonates of iron, lead, and copper are amongst the chief ores of 

 economic importance. The mineral sources of energy upon which 

 modern industrial civilisation largely depends are essentially com- 

 pounds of carbon with hydrogen. In addition to the coal already 

 mentioned are petroleum, oil-shales, bogheads and torbanites. An 

 almost pure form of carbon widely, though not considerably, dis- 

 tributed is graphite; and that wonder amongst minerals and chief 

 of gems, the diamond, is also a form of pure carbon. 



The geology of carbon is too vast a subject to be adequately 

 treated except in an encyclopoedie monograph, and all that will 

 be now attempted is a short sketch of the various theories held on 



IV. 



Geology of Carbon. 



By W. Munn Eankin, M.Sc, B.Sc. 



