Abstract
THE complexity of the heterogeneous conglomerate, coal, can be appreciated if it is considered that it represents the accumulation of vast masses of a large variety of vegetable materials under different climatic and topographical conditions, and their gradual metamorphosis by biological, chemical and physical agencies extending over geological periods which have proceeded to, or are arrested at, varying stages of development. The component portions of a single plant differ widely in their morphological and phytological characteristics and more especially in their chemical composition, that is to say, in the general quantitative relationship of the cellulosic, lignitic, resinic groupings and their quota of normal inorganic plant constituents and accessories, and likewise in the qualitative properties of each of them. Assume this mixtum compositum of raw materials to be subjected to bacterial, enzymatic and chemical decay under varying conditions of wind and water, oxidation, dehydration and carbonisation, rest and disturbance, pressure of superimposed strata and disruptive earth movements, let these phenomena occur in different sequence, at different stages of ‘coalifi-cation’ and with different potency in each region, and you will sympathise with the researcher who attempts to piece the jig-saw puzzle of coal constitution together. He is faced with complexity in the smallest fragment examined under the microscope or by chemical analysis, in any lump taken from the domestic scuttle, when surveying a coal seam throughout its depth and along its bedding plane or a series of seams overlying each other in a single coal pit, when comparing the commercial products of any district or the deposits of the coalfields in different countries and continents.
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References
“Fuel in Science and Practice” Jan. 1935, 14, 4–13.
Copies can be obtained from Dr. M. C. Stopes, Norbury Park, nr. Dorking, England.
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LESSING, R. The Classification of Coals. Nature 135, 642–644 (1935). https://doi.org/10.1038/135642a0
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DOI: https://doi.org/10.1038/135642a0