Report of the Committee on Colour-Vision. 313 



Evidence of Mr. Bambridge, Senior Examiner of the Midland 



Kailway. 



Every applicant for employment, and every servant of the 

 Company on promotion, is examined as to their eyesight. The 

 apparatus used is that which I show. The tests employed are 

 Dr. W. Thompson's tests, consisting- of a series of skeins suspended 

 over a bar, and numbered with numbers which have reference to 

 the colour. Three test skeins are used as standard skeins, the 

 first a blue-green, the second a rose colour, and the third an 

 ordinary scarlet. A candidate is required to match with the 

 first test skein the skeins on the suspended bar, which comprise 

 greens, greys, drabs, pinks, slate colour, and other colours corres- 

 ponding to Holmgren's colours. (The tests were practically 

 carried out after the Holmgren method.) The tests are carried 

 out by daylight, though gaslight tests are sometimes employed. 

 Doubtful cases are re-tested by Holmgren's plan. This method 

 of testing has been in force for eight or nine years ; before that 

 the Army test was employed. The witness believed that the 

 method now employed was very perfect. Should a signalman 

 fall ill he is always tested before he is allowed to rejoin his post 

 with the ordinary signals. In reference to colour-blindness pro- 

 duced by disease, he never saw a man who passed once fail on a 

 further examination. It is quite possible that a man may fail in the 

 wool test who rightly reads signals. The gaslight test takes place 

 in a covered corridor with green and red lights ; but, in addition 

 to this test of signalmen, the wool test must also be passed. The 

 position of the skeins of wool on the bar is not altered, and in 

 case of doubt as to collusion the Holmgren test is adopted. 

 About 2^ per cent, of the whole who are examined fail. Some- 

 times a man may be allowed a second chance of examination if it 

 appears that he fails through ignorance, but he never found that 

 practice enabled a really colour-blind person to pass in a second 

 examination. A man is always examined for colour-blindness 

 after an absence due to an accident in case any alteration in 

 his colour -vision should have occurred. As before said, a man is 

 tested at every stage of promotion, and every applicant has to 

 come to Derby for this purpose. With the aid of assistants, but 

 under the witness's personal supervision, between 1,500 and 

 2,000 candidates for employment are examined each year, and in 

 all 2,500 if old hands are included. Candidates are also examined 

 for form, as in the Army test. The method is by means of dots 

 separated by intervals equal to their diameters. 



A distant signal is often three-quarters of a mile away from 

 the signal box, and the signalman has to see if the arm works 

 in the day time, or if the proper light is shown at night. An 

 engine driver must see a signal about half-a-mile off in order 

 that he may stop his train if necessary. Witness never heard of 

 a case of an engine driver reporting a fireman for want of colour 

 perception. Cases have been heard of in which the colour of 

 light has been mistaken, and in such cases the man would be at 



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