SCIOPTICON MANUAL. 67 



THE EIDOTKOPE. 



This valuable accessory to the magic lantern consists 

 of two perforated metal disks, which, by an arrangement 

 precisely similar to the chromatrope, are made to re- 

 volve one over the other. The effects are so beautiful 

 as to excite surprise that they should be obtained by a 

 mechanical contrivance of such extreme simplicity. By 

 slow revolution, hexagonal, octagonal, and other geo- 

 metrical figures are obtained, with delicate gradations 

 of shadow; while a more accelerated motion produces 

 the effect of stellate flashings, or scintillations of light. 

 Color may be imparted by the use of tinted films of 

 gelatine. Larger disks can be pivoted to a frame above 

 the condenser so as to give an upward and outward 

 movement to the scintillations as from a lower fountain. 

 Stiff paper disks turned contrary ways by the hands at 

 their edges will answer for practical experiments. 



MOVING WATERS. 



Under this title two forms of slides are sold; by means 

 of which, in a single or double lantern, very pleasing 

 effects may be produced. In the simplest form a moon- 

 light scene is painted on a fixed disk, and the " rippling 

 waters" on a piece of glass attached by one corner only 

 to the framework of the slide, which being moved up 

 and down causes the appearance of a ripple on the water. 



Another more expensive, but more truthful effect, is 

 produced by a slide having. two movable and one fixed 

 disk of glass, and known as the " moving water with 

 eccentric motion." In this slide, not only is the ripple 

 produced, but the heaving of a boat upon the waves, the 

 "rolling " of the sea, and the " hovering " motion of birds 

 is imitated with surprising closeness to nature. 



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