A lecture on the progress of physical science since the opening of the London Institution / by W.R. Grove.

  • Grove, W. R. (William Robert), 1811-1896.
Date:
1842
Catalogue details

Licence: Public Domain Mark

Credit: A lecture on the progress of physical science since the opening of the London Institution / by W.R. Grove. 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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    viously compound dischai’ged in almost all its reactions the functions of an element; so in many other cases it was found that compound bodies in which a great number of elements existed, might be regarded as binary combinations, by consi- dering certain groups of these elements as a compound radical; that is as a simple body when treated of in relation to the more complex substances of which it forms part, and only as non-elementary when referred to its internal consti- tution. Undoubtedly by approximating in theory the reactions of inorganic and of organic chemistry, by keeping the mind within the limits of a scientific path, instead of allowing it to wander through a maze of isolated facts, the doctrine of compound-radicals has been of service: but on the other hand, the indefinite variety of changes which may be rung upon the composition of any organic substance by different associations of their primary elements, makes their binary constituents vary as the minds of the authors who ti’eat of them, and depend entirely upon the strength of the analogies presented to each individual mind; from this cause, and from the extreme license which has been taken in theoretic group- ings deduced from this doctrine, a serious question arises whether it may not ultimately, unless carefully restricted, produce confusion rather than simplicity, eccentricity rather than regularity. Dumas has discovered a remarkable class of facts in Or- ganic-Chemistry ; namely, that in certain compounds an equivalent of one element may be replaced by an equivalent of another, differing from it entirely in chemical properties, without essentially altering the character of the substance of which it forms a constituent. Thus the hydrogen of cer- tain compounds may be replaced by chlorine, iodine, or bromine, without materially changing the properties of the compound; he has thence promulgated a theory that the elements of bodies are held together by a species of molecular equilibrium, entirely independent of chemical affinity, and that compounds are to be classed according to what he calls chemical or mechanical Types: the former deduced from their