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

DIAGRAM ILLUSIONS. 25 with a sufficiency of figures to obtain the desired result. It is very different in the photography of moving animals. In taking these, six, eight, ten, or more pictures may be necessary before the same attitude re-occurs; and this, of course, is absolutely necessary to enable the last picture to run on to the first and give an endless repetition of the same movement. Anschiitz was thus obliged to form his Zoetrope (called by him the Tachyscope) as a very shallow cylinder, into which could be inserted a long strip bent round to form the walls. This strip bore the required number of images to complete a cycle of movements, and was pierced with the number of slots necessary to give a correct effect with the number of pictures in the series. Marey not only used photo- graphs but also actual models, on a small scale, of such animals as he desired to show in motion. One of these Stereo-Zootropes is still preserved at the Paris Physio- logical Station, and by the continued observation of successive models in different attitudes the effect is produced of an actual animal running, or bird flying round the interior of the cylinder. In this connection it is interesting to refer again to Desvignes, whose i860 Specification shows a Zoetrope employing solid models. By the construction of his apparatus (Fig. 21) the figures . w fif — m —._ _S-^ were placed on the margin of y^ \ / the cylinder rather than in \l its interior, but the idea is • n • -1 T» /r » t IG. 21. essentially snxiilar to Marey s. Now, one great defect of this, as indeed of every other instrument where the object is in motion while seen through a slit, is distortion. When the object and slit are travelling in the same direction (as in the Phenakistoscope) the object appears elongated, when the reverse is the case (as in the Zoetrope) it