Report of the Committee on Colour-Vision. 319 



factory unless it is applied at the threshold of the sailor's career, 

 and not, as at present, when about to obtain the reward of his 

 years of labour. Before an apprentice or man be allowed to put 

 his foot on board ship as a sailor, he should be compelled to 

 produce to the Captain or Shipping Clerk a certificate of good 

 colour-sight. The matter entails no difficulty. At the present 

 time a sailor is obliged to keep by him his various certificates of 

 discharge, it would be no hardship for him to keep a colour 

 certificate also. 



The Chairman : How can we give a numerical value to your 

 observations ? You know of several cases of officers who are 

 colour-blind, and are sailing the seas, to what extent can you 

 give percentages ? 



The Witness : It is difficult to do this, but we may presume 

 that the percentage of congenital colour-blindness among sailors 

 is the same as that among any other community of males, and 

 by taking the average of the percentages given by three reliable 

 authorities : — 



Holmgren examined 32,165 men — 1,019 colour-blind, 3*168 per cent 

 Joy Jeffries „ 10,387 „ 431 „ 4'149 „ 



London Com. „ 14,846 „ 617 ,. 4'156 „ 



this is found to be 3*824. By the census of 1881, the number of 

 sailors in the Mercantile Marine Service in England was 95,093 ; 

 in Scotland, 14,143, and in Ireland, 10,886 ; making a total of 

 120,122; and this does not include such men as pilots, canal or 

 lighter men. Calculating 3-824 per cent, of this number to be 

 colour-blind, we have a total of 4,593 men holding at the present 

 time positions in which the correct interpretation of coloured 

 lights is essential. 



I am not making allowance for those rejected. But I might 

 call attention to the great variations in the Board of Trade per- 

 centages of rejections, which render their report unreliable. In 

 the official report, published in February, 1885, it is stated 123 

 men were colour-blind out of 21,720 examined, this giving the 

 percentage of -586, and a careful study of this report will show 

 that thirty-one out of eighty-five colour-blind men eventually 

 were granted unendorsed licenses. But the public attention 

 called to this question has raised the percentage, for we are told, 

 in the report of 1888, that between the months of January and 

 May, no fewer than 320 sailors were examined by the Superin- 

 tendent of the Mercantile Marine, at Tilbury Docks, and among 

 them sixteen, or five per cent, were found unable to discriminate 

 red and green in the degree requisite for safe navigation. This 

 percentage one may positively state is as ridiculously high as the 

 former quoted is ridiculously low. Something therefore must be 

 wrong, either with the tests themselves, or with the way in 

 which they are applied. 



All who have consulted me have done so on account of their 

 colour-blindness. A very considerable number of these came to me 

 because they did not believe they were colour-blind. The defect 



