672 ON THE RELATION- OF NATURAL SCIENCE TO ART. 
realism in this respect is perhaps the most curious of all, being so much 
at variance with his idealistic nature. In the possessed boy of the 
“Transfiguration ” a cerebral disease can be almost safely inferred from 
the Magendie position of the eyes, and the circumstance, rec ently ob- 
served in New York, that the left hand is depicted in a spasm of athe- 
tosis would accord well with this diagnosis.* 
ik: 
There is yet another direction in which art owes instructive disclos- 
ures to the progress of photography. In the year 1836, the Brothers 
William and Edward Weber represented, in their celebrated work on 
the “Mechanism of the Human Locomotive Apparatus,” a person in 
the act of walking in those attitudes which according to theoretical 
calculation must occur successively during one step. Thence a strange 
fact became apparent. At the beginning and end of each step, while 
the body rests for a short time on both feet, the pictures agree per- 
fectly with the ordinary way in which painters have been accustomed 
to represent walking persons. But during the middle of the step, 
while one foot is swinging past the other, the effect is highly eccentric, 
not to say ludicrous. The individual appears to be stumbling over his 
own feet like a tipsy fiddler, and nobody had ever been seen walking in 
such a way. On the last page of their book the Brothers Weber pro- 
pose to test the correctness of their diagrammatic figures by the aid of 
Stampfer & Plateau’s stroboscopic disks in the shape of Horner’s 
Diedaleum,t which has (strange to say) returned to us from America as 
a new invention, under the name of “zoétrope” or even ‘vivantos- 
ecope;” but whether the proposal was carried out or not does not 
appear. 
However, William Weber lived to see his assertions thoroughly 
justified almost half a century later by instantaneous photography. 
It was first put into practice in 1872 by Mr. Eadweard Muybridge at 
the suggestion of Mr. Stanford, in order to fix the consecutive attitudes 
of horses in their different paces. The result was the same as in 
Weber’s diagrammatic figures; pictures were obtained which nobody 
could believe to have been seen in reality. On photographs of street 
life and processions the camera frequently surprised people in attitudes 
quite as odd as those attributed to them by the brothers Weber on 
theoretical grounds. The same is the case with the remarkable series 
of photographs of a flying bird during one beat of its wings, obtained 
by M. Marey with his photographic gun. 
The explanation is known to be as follows: An object in motion, the 
speed of which varies periodically, leaves a deeper and more lasting 
*Sachs & Petersen, ‘‘A Study of Cerebral Palsies,” etc., Journal of Nervous and 
Mental Diseases, New York, May, 1890. 
t Philosophical Magazine, January, 1834, 3d series, vol. 11, p. 36, 
