The absorption of light and the colours of natural bodies / by Professor Stokes.

  • Sir George Stokes, 1st Baronet
Date:
1876
Catalogue details

Licence: Public Domain Mark

Credit: The absorption of light and the colours of natural bodies / by Professor Stokes. 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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    THE ABSORPTION OF LIGHT AND THE COLOURS OF NATURAL BODIES. BT PROF. STOKES. LECTURE I. This subject is one which does not admit very well of experi- mental illustration before a large class; in fact, with all the appliances of the electric light, I should only be able to show you, comparatively imperfectly, what you can each see for yourselves by experiments which you can make quietly in your own chambers, requiring, I may say, hardly any apparatus at all. Ihe foundation of what I have to say rests on Newton’s discovery of the compound nature of white light, with which I presume you are already familiar. You know that when a beam of light is allowed to fall upon a prism, it is decom- posed into the different kinds of light of which it consists which are bent round in passing through the prism to a ddlerent degree. Supposing a beam of sunlight reflected horizontally into a room through a small hole and allowed to fall on a prism close by, if the light were of one kind, the beam would be simply ent round as shown in this diagram [referred to], and instead of a circular spot being painted on the wall as at A, it would be as at B But on making the experiment you have actually an elongated coloured image. The cause of that is, the light is not of one kind, but consists of a variety of kinds differirm from one another by the colour with which they impress the eye, and by their refrangibility or capability of being bent