ON THE CONSTRUCTION OF
STEREOSCOPIC KALEIDOSCOPES.
If we apply the Kaleidoscope to any statue or architectural ornament, or any other solid object represented, photographically, on a transparent binocular slide, the figures will be combined into a flat symmetrical pattern, as shown in a future chapter. But if, in the lenticular stereoscope, we place a Kaleidoscope between each of the two semi-lenses and the statue, or other object in the binocular slide, we shall then see the statue or other object in full relief in the symmetrical figure. This, in a rude form, is the Stereoscopic Kaleidoscope.
In order to construct the instrument independently of the stereoscope, we have only to combine two equal Kaleidoscopes, with their reflecting mirrors equally inclined to each other, and place at the eye-end of them two semi-lenses or quarter lenses, at the distance of two and a half inches, and having their focal lengths equal to the length of the stereoscope. If the two right and left eye photographs, to which we apply them, are opaque, upon paper or silver plate, an opening must be left above the object end of the reflectors, of sufficient size to allow light to be thrown upon the photographs. When the figures are transparent, this aperture must be closed.
If the objects in the binocular slides represent either bas-reliefs or alto-relievos, or statues, or vases, or portions of any solid bodies, such as animals, plants, or flowers, which can be combined into symmetrical patterns, they will appear in their true relief in the Stereoscopic Kaleidoscope. In this way the artist may avail himself of the instrument in designing circular Gothic windows, the circular decorations of ceilings, and rectilineal or curvilineal belts, that are to be cut out of metals, marble, freestone, or wood, or formed of plaster of Paris, or metals susceptible of fusion.[11]
If we combine two Telescopic Kaleidoscopes, in the manner already described, so that the centres of their object-lenses are distant two and a half inches, and receive the right and left eye pictures of real objects upon disks of ground glass, with the ground side touching the ends of the reflectors, these objects, though themselves in true relief, will be reduced to plane pictures on the ground glass, and again brought into stereoscopic relief, and combined into symmetrical patterns by the instrument. The effect thus produced is different from what we should see were the ground glass removed, and the image of the object formed in the air at the end of the reflectors, for the same reason that the picture of an object in the stereoscope is different from what it appears if viewed directly by the eyes.