THE BOOK OF THE LANTERN. 179 



tinuous ring of fire, but we know well enough that it is 

 simply a spark. It is the rapid movement helped by this 

 " persistence " of the retina, that causes the spot of light to 

 appear to us as a continuous circle. So it is that heavy 

 rain drops, which we know very well are independent 

 globules of water, appear to be like streaks falling from 

 the sky, and like streaks artists invariably depict them. 

 And rightly so, too, for we do not wish artists to bring 

 before us representations of things as the eye cannot see 

 them, but of objects as they appear to us under ordinary 

 conditions. For this reason the claim which has been made 

 in some quarters, that the unusual attitudes depicted by 

 instantaneous photography, should be a help to artists in 

 their delineation of animal movement, appears to be ex- 

 tremely nonsensical. Such attitudes may certainly be 

 studied by artists, as a means of showing how the various 

 movements are brought about, just as he would study the 

 skeleton of a man, in order to get a better notion of the 

 outward form of the body; but both should be kept as 

 studies, and certainly not introduced into finished works. 



The kaleidotrope consists of a disc of perforated cardboard. 

 It is supported on a spring of wire in such a manner that it 

 can be rapidly turned round by the finger as the frame in 

 which it is contained stands upon the lantern stage. The 

 other end of the spring is cemented to a plate of glass so 

 that the light can easily travel through the perforations in 

 the disc and be rendered evident on the lantern screen. 

 As this card is struck with the finger so as to cause it to 

 move and vibrate on its spring in different directions, 

 the spots of light on the screen by their movement assume 



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