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doi: 10.1038/042126d0
IN answer to Prof. Lodge's query (May 29, p. 100), why those concerned in testing for colour-vision do not avail themselves of instruments like Lord Rayleigh's, having tested some thousands in this city, I may state that experience has shown that they are not suited for testing uneducated persons. A similar instrument, introduced by Chibret and Meyer, of Paris, is to be found in ophthalmic hospitals.
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