ABSTRACT
The optical instrument is an application of the principle of the stereoscope to that class of instruments variously termed thaumatropes, phantascopes, phenakistoscopes, which depend for their results on “persistence of vision”. In these instruments, as is well known, an object represented on a revolving disc, in the successive positions it assumes in performing a given evolution, is seen to execute the movement so delineated. In the stereotrope the effect of solidity is superadded, so that the object is perceived as if in motion and with an appearance of relief as in nature. The form of the stereotrope, in which Professor Wheatstone’s reflecting stereoscope is made use of, and which is better adapted for the exhibition of movements that are not only local but progressive in space, because the principles it involves are essentially the same as those which are stated.
