In the formation of the Kaleidoscope figures, it is necessary to pay particular attention to the colour of the objects of which they are to be composed, _red_, _orange_, and _dark yellow_ objects, which transmit few, if any, actinic rays, should not be employed. Blue glasses, which transmit no red rays, are actinically more luminous than colourless glasses, and therefore pale blue, pale green, and pale yellow glasses may be advantageously combined with colourless glasses as objects for the object-box. When we wish to copy photographically the pictures obtained from external objects, we must use the Telescopic Kaleidoscope of Mr. Bates, by which the images of these objects are formed at the extremity of the reflectors. These objects may be flowers, plants, architectural ornaments, or parts of them, paintings, photographs, statues, or loose and irregularly placed materials of any kind. In the figures created by the common Kaleidoscope, we must trust to chance for the formation of the figures, and can only choose those which we like out of a large number accidentally formed; but when we make use of external objects, we can group them and illuminate them in any manner we choose, selecting those forms and colours which, when combined, produce the effect that we desire. This power, of arranging the objects, when in contact with the ends of the reflectors, may be obtained with the Kaleidoscope of Mr. Bates, shown in Fig. 29, by removing the anterior half of the cone when the objects are opaque, and placing the camera in a vertical position. The objects being placed upon a horizontal plate, may, if opaque, be illuminated, by reflected light, and the picture of them, when combined by the Kaleidoscope, taken in the same manner as when the instrument was in the position shown in Fig. 52. If the figure is not what we like, we can shift any individual object, or remove it, or replace it by another, till we are satisfied with the combination. The very same power of altering the combination, may be obtained for transparent objects. We have only to place these objects on a horizontal plate of glass, not connected with the Kaleidoscope, but capable of being removed from it, and again brought close to the ends of the reflectors. When the objects on the glass plate have been put into their proper place, so as to give the desired picture, the plate is brought as near as possible to the ends of the reflectors, and the objects are illuminated either by solar or other light reflected upwards upon the object-box. CHAPTER XXII. ON THE ADVANTAGES OF THE KALEIDOSCOPE AS AN INSTRUMENT OF AMUSEMENT.