Living pictures; their history, photoproduction and practical working. With a digest of British patents and annotated bibliography (1899)

DIAGRAM ILL US IONS. 31 the screen. But even with these imperfections this arrange- ment marks the culminating- point in the development of the Praxinoscope type, another form of which instrument devised by the same inventor, deserves mention from its extreme simplicity. It was called La Toupee- fantoche or Marionette-top, and, as seen in Fig. 28, consisted of four mirrors arranged as a pyramid and surmounted by an inter- changeable card bearing four designs. The whole was placed on a spindle, and, when rotated, gave a moving image on exactly the same principles as those governing the more elabo- rate devices previously de- scribed. Although this type of instrument has not been further developed, it is worthy of notice that during the year 1897 two patents at least were applied for having as their central feature a mirror which by its movement rendered the continuously moving picture optically stationary. But in the use of one mirror its slow movement must be followed by a quick return in order to register with the succeeding view ; and this quick return, though it saves strain on the film, is yet optically equivalent to a rapid removal of the picture without that movement being covered by a period of darkness. Still, ideas move slowly, and Reynaud's polygonal revolving mirror may yet be applied to the projection of series views of greater complexity than his simple figures afforded. In following out the cylindrical type of instrument we have come nearly up to date; but there is one other class of device, employing diagrams with a view to Fig 28.