Address / of George Gabriel Stokes.

  • Sir George Stokes, 1st Baronet
Date:
[1869?]
Catalogue details

Licence: Public Domain Mark

Credit: Address / of George Gabriel Stokes. Source: Wellcome Collection.

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    novelty of principle was to be looked for in the department of astronomy; for such we must go to younger and less mature branches of science. Researches which have been carried on within the last few years, even the progress which has been made within the last twelve months, shows how short-sighted such an anticipation would have been; what an unex¬ pected flood of light may sometimes be thrown over one science by its union with another; how conducive accordingly to the advancement of science may be an Association like the present, in which not only are the workers at special sciences brought together in the Sectional Meetings, but in the General Meetings of the Association, and in the social intercourse, which, though of an informal character, is no unimportant part of our procedings, the cultivators of different branches of science are brought together, and have an opportunity of enlarging their minds by contact with the minds of others, who have been used to trains of thought of a very different character from their own. The science of astronomy is indebted to that of optics for the principles whch regulate the construction of those optical instruments which are so essential to the astronomer. It repaid its debt by furnishing to optics a result which it is important we should keep in view in considering the nature of light. It is to astronomy that we are indebted for the first proof we obtained of the finite velocity of light, and for the first numerical deter¬ mination of that enormous velocity. Astronomy, again, led, forty-four years later, to a second determination of that velocity in the remarkable pheno¬ menon of aberration discovered by Bradley, a phenomenon presenting spe¬ cial points of interest in relation to the nature of light, and which has given rise to some discussion, extending even to the present day, so that the Astro¬ nomer Royal has not deemed it unworthy of investigation, laborious as he foresees the trial is likely to prove, to determine the constant of aberration by means of a telescope having its tube filled with water. If in respect of these phenomena optics received much aid from astro¬ nomy, the latter science has been indebted to the former for information which could not otherwise have been obtained. The motions and the masses of the heavenly bodies are revealed to us more or less fully by astronomical observations; bju t we could not thus become acquainted with the chemical nature of these distant objects. Yet, by the application of the spectroscope to the scrutiny of the heavenly bodies, evidence has been obtained of the existence therein of various elements known to us by the chemical examina¬ tion of the materials of which our own earth is composed; and not only so, but light is thrown on the state in which matter is there existing, which, in the case of nebulae especially, led to the formation of new ideas respecting their constitution, and the rectification of astronomical speculations pre¬ viously entertained. I shall 'not, however, dwell further on this part of the subject, which is now of some years’ standing, and has been mentioned by