On the allotropic changes of certain elements / B.C. Brodie.

  • Brodie, Benjamin, Sir, 1783-1862.
Date:
[1852]
Catalogue details

Licence: Public Domain Mark

Credit: On the allotropic changes of certain elements / B.C. Brodie. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Portraits of Sir B. C. Brodie and the Rev. T. Eagles, and Sketch of a Poor Irish Girl, by J. Z. Bell, Esq. 15 Ammonites from the Secondary Formations, Exhibited by Mr. Tennant; and an Engraving of the “ Ammonites Heterophyllus,” presented by him to the Royal Institution Library. Mr. Varley showed by the Microscope the beating of the heart in the Monoculi and Wheel-animalcules. WEEKLY EVENING MEETING, Friday, May 21. W. R. Grove, Esq., M.A., F.R.S., Vice-President, in the Chair. B. C. Brodie, Esq. / On the Allotropic Changes of Certain Elements. The earliest conception of the nature of a chemical substance was limited to the knowledge of the ultimate or elemental particles into which it could be broken up. To this after a time was added that of the proportion in which these elements were combined. But this too proved inadequate to explain the chemical differences of bodies, especially their dynamic differences, that is, the different modes of change of which they are susceptible — why for example, from certain bodies containing many atoms of hydrogen, one of these atoms can readily be removed and replaced by a metal, while no skill has yet effected a similar exchange with a second. The progress of discovery, moreover, established beyond a doubt the existence of a class of bodies consisting of the same elements, combined in the very same proportions, which yet differed in their chemical and physical properties. To meet these and other difficulties, gradually arose an idea new to chemical science, the idea of structure or chemical form, in the elaboration of which, chemists of late years have been principally engaged. The way in which this conception (has been applied to explain the relation of isomeric bodies may be C H is represented as 2 jj5 O = C2 H6 O, and methylic ether as O. = C2 H6 O. This last substance is identical with alcohol in its elemental constitution, but differs from it in its