A simple effective stereoscope for exhibiting a large number of views is shown in the accompanying sketch. The apparatus consists of a box A with sliding adjustment along a wood strip B similar to the usual form of cheap stereoscope. At the back of the box at 0 are two spiral springs which sink into a recess. By these springs the front picture is kept in position, whatever number of views the box may contain. Across the front of the box is a rod D worked by a handle E. With this rod turn two rubber-tyred wheels F, one on each side. To use the apparatus, the box is filled with pictures (which should be pasted on thin mounts), and the focus is adjusted for the front picture, which is removed as soon as it is done with by turning the handle in the direction indicated, when the wheels F drag the picture out of the way and it falls into the top. The next picture, pressed forward by the spring, is already in position. This apparatus might easily be constructed in pedestal form if the focal adjustment is effected by means of a long screw with a handle and a nut in the bottom of the box.

The changing handle would, of coiu-se, be fixed outside by lengthening the rod D.

Stereoscope for Holding a Number of Views.