314 MOVEMENT 



M. Raynaud's Praxinoscope. — Under this title, M. 

 Raynaud has given to the world an extremely ingenious 

 instrument. As in the ordinary zootrope, the figures 

 are arranged within a cylinder, and are reflected by a 

 prismatic mirror situated at the centre of the apparatus, 

 and thence reach the eye of the observer. The con- 

 trivance is peculiar in that the substitution of one 

 position for another is effected without any intermediate 

 eclipse, so that the images, owing to the constant 

 illumination, appear exceedingly bright. By inter- 

 posing a photographic object-glass in the path of the 

 reflected images, M. Raynaud has thrown them upon 

 a screen, and magnified them to the required dimensions. 

 Finally, by substituting for the flat circular strip of 

 figures a long strip which winds off one roller on to 

 another, the writer has been able to display a per- 

 formance of considerable duration. As yet, M. Raynaud 

 has only employed figures drawn or painted by hand ; 

 doubtless he could obtain remarkable results by 

 substituting a series of chronophotographs. A slight 

 defect in the apparatus is that the plane of the pro- 

 jected images is slightly oblique as regards the principal 

 axis of the object-glass, this is due to the construction 

 of the apparatus. It is thus impossible that all the 

 parts of the images can be in focus, and hence the 

 projection on the screen is somewhat indistinct. 



M. Demeny's Ph otophone. — M. Demeny has employed 

 another method for reproducing the movements of the 

 face, the tongue, and the lips, executed during speech. 

 My assistant at the Physiological Station has prepared 

 on a length of film a chronophotographic series con- 

 sisting of twenty-four portraits of a man articulating 

 certain words. When this series of portraits was trans- 

 ferred to the circumference of a glass disc and placed 

 in the focus of a photographic object-glass, they were 

 brightly illuminated from behind, and rendered visible 



