ON THE RELATION OF NATURAL SCIENCE TO ART. 673 
impression on our mind in those positions which it occupies longest, 
while the impression is fainter and more fleeting in those through 
which it passes quickly. Apart from all knowledge of this law, a 
painter would never represent a Dutch clock in a cottage with the 
pendulum at the perpendicular, as every spectator would inquire why 
the clock had been stopped. The pendulum, having swung in one di 
rection, necessarily stops for a moment while preparing to return in 
the other, and consequently its diverging position is more vividly 
stamped on our minds than those during which it passes through its 
position of rest with a maximum of speed. Precisely the same thing 
occurs with the alternately swinging legs of aman during the act of 
walking; the body remains longest in the position in which both feet 
support it, and shortest in that during which one foot swings past the 
other. We therefore receive scarcely any impression from the latter 
series of attitudes. We imagine a walking person, and painters 
accordingly represent him, in the interval between two steps, with 
both feet touching the ground. 
In the case of a running horse, however, particular circumstances 
intervene. However rapid the succession of instantaneous photo- 
graphs, we never obtain the usual image of a racing horse such as it 
appears in large numbers in the print-shops at the racing season, and 
such as we suppose we actually see in reality. It is different in the 
case of man; there among pictures obtained methodically or by chance, 
which have, so to speak, never been perceived by the naked eye, some 
will always occur which agree with the usual aspect of a walking per- 
son. The difference consists in this, thatin a racing horse the interval 
of time, during which the fore legs remain in complete extension, does 
not coincide with that during which the hind legs are fully extended. 
Both these positions prevailing in our memory, they are subsequently 
blended into the traditional picture of a race horse, whereas instan- 
taneous photography fixes them successively. Consequently the tra- 
ditional picture is wrong, and exhibits the horse in a position through 
which it does not even transitorily pass. 
In the year 1882, an illustrated American paper brought out a picture 
of a steeple-chase, in which all the horses are copied from Muybridge’s 
photographs, in attitudes only visible to a rapid plate. This ingenious 
sketch was communicated to us by Prof. Eder in Vienna, in a pamphlet 
on instantaneous photography, and a stranger spectacle can not well 
be imagined. The correctness of these apparently wrong pictures can 
however be proved by realizing the idea originally suggested by the 
brothers Weber, and integrating into a general impression the period- 
ical motion which has been resolved, as it were, into differential 
pictures. This is done by gazing in the deedaleum at a series of photo- 
graphs taken at sufficiently brief intervals from an object in periodical 
motion, or illuminating or projecting it momentarily during its rapid 
flight past the eye. The latter method has been put into practice by 
H. Mis. 334, pt. 1 43 
