Report of the Committee on Colour-Vision. 365 



description and instructions printed at the back. The card was 

 obtained at the Horse Guards some time' ago. As regards the 

 test adopted in the Superintendent's Department for Signalmen 

 and others under the control of the Traffic Superintendent, I 

 cannot do better than send you a copy of a report from our 

 Medical Officer with reference to the means which he adopts to 

 test the Colour Vision of the men in that Department. 



" Yours faithfully, 



"JOHN MORGAN, 



" Secretary. 



" The Secretary, Colour Vision Committee, 



"Royal Society, Piccadilly, W." 



" The Avenue, 



" Brixton Hill, 



" July 9, 1890. 



" Dear Sir, — In accordance with your instructions of 

 July 5th to report on the means employed to test the railway 

 servants on L.C. &> D.R. as to their ability to detect colours, the 

 following apparatus is in use. 



" It consists of a hollow tube about 12 inches square and 22 inches 

 long. At one end of it is a revolving disc having let into it as near 

 as possible the seven primary colours, great care being taken 

 that the red, green, and purple are of the same hue as the actual 

 signals : — 



" The disc is illuminated at the back, thus giving the colours 

 much the appearance they have on the signals. 



" This appliance meets with all necessary requirements, and is 

 a fair test as to the men's capabilities of detecting colour. 



" On examination they are instructed to look down the tube, 

 and by means of a handle any one of the colours can be shown 

 at will, so that no two men coming up need have the same series 

 of colours. This is very important, as when a number of candi- 



