Observations on bituminous substances, with a description of the varieties of the elastic bitumen ... Read in the Linnaean Soc / by Charles Hatchett.

  • Charles Hatchett
Date:
[1798]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on bituminous substances, with a description of the varieties of the elastic bitumen ... Read in the Linnaean Soc / by Charles Hatchett. Source: Wellcome Collection.

    11/28 page 137
    agoing pages, the fimple bituminous fub fiances appear to pafs into thole which are compound ; and tbefe alfo, by declining fhades, at laft pafs into fubftances .appertaining to the clafs of earths anti hones. In the compound bituminous fubftances the prevalent earthy ingredient is for the greater part generally, if not always, argillaceous; and although certain calcareous grits (fuch as the Portland hone*) as well as limeftones and marbles .are found impregnated with Bitumen, yet I know not,of any inflance in which this happens to the degree requifite to form a corabuflible fubftance. This curfory view of the fimple bitumens, and of their combina¬ tions, would he fufficient as an introduction to the principal fubjeCt of this paper ; but, to complete the feries, I fltall make fome obfer- vations on the vegetable fubflances which contain bitumen, and (hall afterwards mention the mixtures of bitumen with metallic, oxides. § 4- WHEN we confider the faCts which apparently prove that vege¬ tables have contributed principally to the formation of bitumen, we have every reafon to expeCt that mixtures of vegetable matter with bitumen fhould frequently occur. But by the mixture of bitumen with the parts of vegetables, we underhand the remains and parts of vegetables mixed and connected with the bitumen which they themfelves have produced. This feems to be the nature of the fubftance called * The Portland (tone, when recently broken in the quarries, emits adrong bituminous odour, like the bituminous limeftone or dink-done. It is alfo full of extraneous fodlls, 01 ^t lead the vediges of them. Vol. IV. T BIT U-
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