ART AND EYESIGHT. 461 



average, a degree of astigmatism which technically would be 

 written 0"68 of a dioptre, this dioptre corresponding to a certain 

 weak glass used as the unit of measure. 



Among artists, on the other hand, the examination showed 

 that the average was 0*83 of a dioptre, thus being decidedly greater 

 than with persons having other occupations. 



It would be interesting to study the degree of this fault as re- 

 lated to the style of the artist, but the limits of this paper do not 

 permit such a long digression. Moreover, this number is small, 

 and there is always danger in generalizing from insufficient data, 

 but I think it fair to say that these facts are sufficient to show the 

 comparatively high degree of the astigmatism of artists, and I am 

 confident that corroborative testimony will not be wanting when 

 this subject is studied by others. Nor is this idea by any means 

 a new one. It is true, exact measurements of the vision of so 

 large a number of painters had not been previously made, but long 

 ago the effects of astigmatism were so conspicuous in some well- 

 known pictures as to attract attention. 



A quarter of a century ago no oculist was more prominent 

 than Prof. Liebreich, of London, or better able than he to speak 

 on questions relating to optics. Unfortunately for that branch of 

 science, he came into a fortune, and, giving up the labors of pro- 

 fessional work, devoted himself to the study of painting, thus 

 doubling his equipment for the investigation of such questions as 

 these. He turned his attention to the pictures of Turner and 

 Mulready, both of whom have prominent places in the National 

 Gallery and at the Kensington Museum, and in the works of 

 these artists Liebreich's trained sight discovered incontrovertible 

 evidences of defective vision. These facts were brought out in 

 1863 by Liebreich in a communication to the Royal Institution 

 which still lies buried among its archives. 



" Till the year 1830," he says, in speaking of Turner, " all is 

 normal. In 1831 a change in the coloring becomes for the first 

 time perceptible, which gives to the works of Turner a peculiar 

 character not found in any other master. Optically this is caused 

 by an increased intensity of the diffused light proceeding from 

 the most illuminated parts of the landscape. . . . From the year 

 1833 this diffusion of light becomes more and more vertical. It 

 gradually increases during the following years. At first it can 

 only be perceived by a careful examination of the pictures, but 

 from the year 1839 the regular vertical streaks become apparent 

 to every one. ... It is a generally received opinion that Turner 

 adopted a peculiar manner, that he exaggerated it more and more, 

 and that his last works are the result of a deranged intellect. I 

 am convinced of the incorrectness I might almost say of the in- 

 justice of this opinion. . . . According to my opinion, his manner 



