Colour blindness and defective eyesight in officers and sailors in the merchant marine : a criticism of the Board of Trade tests / by Thomas H. Bickerton.

  • Thomas Herbert Bickerton
Date:
1890
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Licence: Public Domain Mark

Credit: Colour blindness and defective eyesight in officers and sailors in the merchant marine : a criticism of the Board of Trade tests / by Thomas H. Bickerton. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    knowledge of this subject to lose, who will corrobate it. The test, as a test of the colour sense, is not worth the paper it is written on. And their second test, which takes place in a darkened room, and consists in the candidate being asked to name the colour of various illuminated coloured glass slides, shown separately, is, so far as reliability is concerned, on a par with their first. If, says the report, a man can clearly dis- tinguish red from green, and both from black and white, he will be able to follow the international rules for the prevention of collisions at sea. Quite so; but to distinguish colours clearly and to name colours correctly are two very different matters. When will the Board of Trade understand that to ask a candi- date to give the name of a colour is a test not of the colour sense but of education in the names of colours, and that to rely implicitly on the correct naming of colours opens the road for an utterly wrong conclusion ? An educated colour blind may, and often does, succeed in guessing the names correctly. According to the Board of Trade, this colour-blind man is not colour blind, and, receiving their certificate, he becomes more dangerous to the community thail ever, for his defective colour sense is thus authoritatively made perfect colour sense. On the other hand, an uneducated man with a perfect appreciation of colours, though ignorant of their names, would be, according to their rules, colour blind. That at one time the official mind had a glimmering of this fact is indicated by the third test mentioned in the report of 1885, namely, that in some cases in which the examiners decide that the applicant has failed, and in which the applicant holds a contrary opinion, as well as in cases which may, in the examiner's mind, raise a doubt as to the propriety of passing him, the facts are reported to the Department with full particulars, and the applicant is retested by means of a modification of Holmgren's system of coloured worsteds. Now, if, as the report says, the first and second tests are sufficient for the purpose intended, why need a third test? And if, when a doubt in the examiner's mind does arise, he is advised, m order to settle that doubt, to apply a third test, is it not clear to an unbiassed mind that the third test is a more reliable one ? Why, then, is it that this last test is not made the crucial test in all cases ? This third test (Holmgren's)