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THE POPULAR EDUCATOR. 



understood laws of Nature, and known to exist in the animal 

 structure. 



It may be observed in the previous papers how much 

 ingenuity has been displayed by the various inventors viz., 

 Paris, Plateau, Eose, and Beale in the construction of instru- 

 ments, all of which illustrate the phenomena, simple or com- 

 plicated, of the duration of impressions of light upon the 

 optic nerve. In two very marked instances we have found 

 Dame Nature has been before the earliest foaman inventor in 

 the splendid meteors of the skies, and the tiny creature called 



movements that might be made by a skeleton if worked by 

 mechanical means, as by threads in the ordinary exhibition of 

 Marionette figures, six of which are shown in Figs. 3, 4, 5, 6, 

 7, and 8. The number of positions, say ten, correspond to the 

 divisions of the piece B. With the handle D (Fig. 1) the pic- 

 tures of the skeleton are successively brought into position beforo 

 the condensing lenses of an oxy-hydrogen lantern E (Fig. 2); and 

 in order to prevent any motion being perceptible, which is 

 usually so injurious to optical deception of this class, the 

 " Intercepter," F (Figs. 1 and 2), cuts off the light during the 



the wheel animalcule. Still, however, the subject seems inex- 

 haustible, and another addition has been made to the contri- 

 vances for producing apparent motion in the very ingenious and 

 most perfect apparatus invented by Mr. John Beale, and adapted 

 for use in the oxy-hydrogen lantern. The illusion called " The 

 Dancing Skeleton," which has created quite a furore when- 

 ever shown by the writer, in his optical lectures, consists, as 

 shown in Figs. 1 and 2 (representing the two most important 

 positions of the instrument), of a shaft A, carrying at one 

 end the intermittent motion- piece B, and at the other end 

 of the shaft a disc of aluminium c, selected for its lightness. 

 This circular piece of metal has the figure of the grisly King of 

 Terrors cut through it in any number of positions ; in fact, 

 they constitute admirably desirfnod stencil plates of the various 



motion. The light which passes through the aluminium disc 

 plates, and which represents the figures of the skeleton, i^ 

 properly focussed and thus sharply defined on a white screen by 

 proper lenses ; and the general effect produced by causing the 

 skeleton to rise in another view already on the white screen, 

 representing a churchyard or a vaulted chamber, is perfectly 

 magical in effect, and far surpasses any mere painted slides 

 which might be used to represent a scene such as the grand ir.- 

 cantation scene of Der Freischutz. There is also a grotesque- 

 ness in the movements, which deprives the exhibition of any 

 alarming effect on the juvenile mind, whilst the ingenuity of 

 the apparatus in producing such complicated movements in a 

 figure projected on to a white screen, interests the more sober 

 part of a mixed audience. 



