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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    IG L-ombiniiig properties, tlie latter from their iminerical ecpii- valents. Whatever be the value of bis theory, many of the faets observed by Dumas are of great importance; and if not of sufficient generality to originate new views of chemical action, must be regarded as curious exceptions to the re- ceived doctrines. Catalysis, or the chemical action induced by the mere presence of a foreign body, embraces a class of facts which must modify considerably many of our notions of chemical action; thus, oxygen and hydrogen when mixed in a gaseous state, will remain unaltered for an indefinite period; but the introduction to them of a slip of clean platinum will cause more or less rapid combination, without being in itself in any respect altered: on the other hand,oxygenated water, which is a compound of one equivalent of hydrogen plus two of oxygen, will, when under a cei’tain temperature, remain perfectly stable, but touch it with platinum in a state of minute division, and it is instantly decomposed, one equiva- lent of oxygen being set free: here again the platinum is unaltered, and thus we have synthesis and analysis effected by the mere contact of a foreign body. I am strongly dis- posed to consider that the facts of Catalysis depend \ipon voltaic action, to generate which three heterogeneous sub- stances arc always necessary: Induced by this belief I made some experiments on the subject, and succeeded in forming a voltaic combination by gaseous-oxygen, gaseous-hydrogen, and platinum; by which a galvanometer was deflected and water decomposed. The detection of diversity of chemical constitution by what is called Circular Polarisation of Light, took place before the opening of this Institution, but its application to Chemistry by M. Biot is of later date, and forms a beautiful instance of the connexion of the different branches of Phy- sical Science, and of the practical value of such connexion. Light, as you know, when j)olarised appears to be transmitted by undulations in certain planes, and to be incapable of transmission in planes inclined to these at right angles. In ordinary cases of polarisation, each of the colours which