NATURE'S GIFT

Evening Post, Volume CV, Issue 150, 29 June 1928, Page 6

NATURE'S GIFT

ORIGIN OF COAL y INTERESTING LECTURE ' "The Origin and Structure of Coal" was the title of a very interesting lecture given last night by Dr. W. P. Evans to the Philosophical Society. Tho attendance was small, but thoso present thoroughly appreciated . tho lecture, •which wan illustrated by a series .of magnificent lantern slides. , Dr. Eviins said that Iv vauld not attumpt a definition of ct.'. It was. a substance with 'which t/oryone was familiar, but most people had the erroneous idea that it was black, whereas, as a, matter of fact, it was full of colour.' It had a banded appearance, there being scams within seams. These seams were lens-shaped, although that, was not necessarily the original shapo of the seam. Kecent' research had shown that all coal, even lignite/revoaled.definite structure finder the microscope if sections wore properly prepared and examined. Some lumps preserved the identity of tho wood to a remarkable degree, and even cuticle could be seen in some Eussian coal of the carboniferous period. From some Teriary'coal it had been found possible to extract chlorophyll. . . Discussing the origin of coal, Dr. Evans said -that it had been foumd at all geological periods: all that appeared necessary for coal formation was that a certain amount of vegetable. material should be deposited before it had time to decay into inorganic material. . No special type of vegetation, climate, or geological horizon was necessary, for the formation of coal. We knew that coal was formed from vegetable matter, from a vast compost heap accumulating generation after generation, submerged with sufficient water and sufficient oxygen. Coal formation had never taken place in sea'water, although perhaps it had sometimes in brackish water. There were two theories as to how this accumulation took place. In one it was. maintained that the forests grew where the coal deposits are now found, and in the other that the-coal formations are the result of drift. Bach hypothesis had a certain amount of evidence to support it, but the weight of evidence seemed to be in-:favour of the drift, theory, although in some cases both hypotheses probably held good.. "Dame Nature does not make all her shoes on the same last." If the in situ theory was the correct one, it seemed strange that so few big pieces of vegetation were found in the subsequent coal; the structural details, too, seemed to support the drift theory. The sedimentation or drift theory was supported by tho fact that superimposed layers of coalvwere frequently found, as many as 76 in one place. It was not necessary to postulate the many millions of years proviously thought necessary for the formation of coal. It could, in fact, be formed in a few hours under certain conditions. It sometimes happened that a pine pile encountered rock. When withdrawn after sufficient "hammering the wood was found to be converted into brown coal on the outside and into anthracite coal in the central portions. Butf normally, there was no doubt, the formation of coal took a very long time. During the lubsequent discussion, Professor Kirk said that a fow years ago such wonderful slides of the microscopic structure of coal as had been shown, that evening would have been an inir possibility. The etching method adopted by Dr. Evans had only been achieved by painstaking effort.