268 KEPOKT— 1881. 



recruits only were concerned, viz., the distance at which dots of the 

 same size appear separate to the eye, and can be counted, varies with the 

 space between them. Four rows of dots of ^-inch square were placed 

 on a card ; those of the first row were separated from each other by 

 spaces of the same size left blank ; in the second row each dot was 

 separated from those in its vicinity by f of an inch ; in the third row 

 the distance of each dot from any other was f of an inch, and in the 

 fourth row f of an inch ; and a single dot was placed on one side 1'5 

 inch from the nearest one in the rows. These were exposed in the open 

 air, on a bright day, in a situation affording a clear range of about 

 90 feet ; at that distance from the card the single dot was quite percep- 

 tible, and those in the first, second, and thii-d rows had the appearance of 

 continued lines. On approaching the card the dots in the fourth row 

 could be counted at 82 feet, those in the third at 74, in the second at 

 58, and in the first only at 36 feet. The ordinary cards of dots, therefore, 

 on which these are separated by spaces vai-ying from one to a little over 

 two diameters can only give a comparative test of the acnteness of vision 

 among those examined, and not an absolute one such as a card with 

 intervals of not less than five times the diameter of the dots between 

 every two of them would afi'ord. Dots so arranged could not be grouped 

 readily, but they could be shown in varying numbers to the person under 

 trial, and his replies would indicate whether he were able to distinguish 

 them. 



Mr. Roberts's Rejiort on the Observations on Eyesight and Colour-blindness 

 made at Marlborough College by the Rev. T. A. Preston. 



The diificulty experienced by many observers of obtaining suflicient 

 space and light for testing the eyesight by the test-dots (which are 

 distinguishable to the normal eye in good daylight at a distance of 19 

 yards) has induced the Committee to use Snellen's test-types, No. 1 and 

 No. 10, as more convenient and trustworthy. No. 1 is a small type 

 visible to the normal eye at the ordinary reading distance of from 12 to 

 20 inches, and No. 10 is a large thick type ith of an inch square, dis- 

 tinguishable by the normal eye at a distance of 10 feet. 



The Rev. T. A. Preston, one of the masters at Marlborough College, 

 has examined the eyesight and colour-sense of the whole of the boys and 

 some of the masters at present in the College, and the following is an 

 analysis of his returns. The observations include the age, the colour of 

 the iris, the eyesight as tested by No. 1 and No. 10, and the letters 

 composed of horizontal and vertical lines for astigmatism ; and the 

 colour-sense as tested by the methods of Dr. Daae and Professor Holm- 

 gren (and in a few instances by the solar spectrum), according to the 

 book of tests wliich I have prepared for the use of the Committee (' The 

 Detection of Colour-blindness and Imperfect Eyesight ' : Bogue). 



Age. — The ages of the boys range from 11 to 19 years, and those of 

 the masters from 20 to 50 years, five of the latter being over 40 years. 



Colour op Eyes. — The following Table shows the colour of the eyes 



