The relation of light perception to colour perception / by F.W. Edridge-Green.

  • Edridge-Green, F. W. (Frederick William), 1863-1953.
Date:
1910
Catalogue details

Licence: In copyright

Credit: The relation of light perception to colour perception / by F.W. Edridge-Green. 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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    [.Reprinted from the Proceedings pe the Eoy-al Soo^y, B. Yol. 82] The Relation of Light Perception to Colour Perception. By F. W. Edridge-Green, M.D., F.B.^.S'^git MedicaFBesearch Fellow. (Communicated by Prof. E. H. Starling, F.E.b. Received June 3,—Bead June 30, 1910.) (From the Institute of Physiology, University College.) Since the majority of the theories of colour perception which have been propounded have been really theories of light perception, the two subjects, namely, colour and light perception, though really quite distinct, have become so interwoven in the discussion of the question that many seem quite incapable of distinguishing the two. Yet it may he easily shown that light perception and colour perception are quite distinct. In fact, we can divide cases of colour blindness into two classes, according as the defect is (a) one of light perception, or (h) one of colour perception or differentiation without any defect in light perception. Of course, both defects may be present in the same individual. The investigation of these two classes of defective vision is much facilitated by the use of a spectrometer which I have devised for the purpose, and which is so arranged as to make it possible to expose to view in the eye-piece the portion of a spectrum between any two desired wave-lengths. It consists of the usual parts of a prism spectroscope, i.e. a collimator with adjustable slit, prism, and telescope with eye-piece of the following dimensions:— Focal length of collimator and telescope object glasses = 7£ inches (180 mm.). Clear aperture of collimator and telescope object glasses = £ inch (22 mm.). Slit, 7 mm. effective length of jaw, with wedge for reducing the effective length of the slit, protective cap, comparison prism, and screw adjustment for the slit width, with divided head. The prism is of flint glass, l-65 refractive index for D. Eye-piece, Bamsden form, focussing on to the shutters described below. In the focal plane of the telescope are two adjustable shutters with vertical edges, the shutters being carried by levers which rotate about centres near the object glass of the telescope. The shutters can be moved into the field from right and left respectively, each by its own micrometer screw, and to each screw is attached a drum, the one being on the right and the other on the left of the telescope. On each of these drums is cut a helical slot in which runs an index, and the drum is engraved in such a manner that the reading of the index gives directly in wave-lengths the position in the spectrum of the corresponding shutter. 6