Bate's Kaleidoscopes, with metallic reflectors, is shown in the annexed figure, where MCDN is the body of the camera, m n o p the tube which is moved out and in by a milled head attached to the pinion which drives the rack on the tube m n o p. The Kaleidoscope ABL L, exhibiting the figure which is to be copied, is temporarily fixed in this tube by pieces of cork or wood, so that its axis, or the line of junction of the reflectors, may be perpendicular to the surface of the grey glass p q, which can be taken out, so as to allow the collodion or paper slide to be placed in the same groove. The pictures should always be taken, when it is possible, by sunlight incident obliquely upon the object-box, or with the illuminators already described. When this cannot be done, artificial light, containing the actinic or chemical rays, may be thrown upon the object, as shown in Fig. 52. The light of coal gas, which may be condensed for any length of time upon the objects in the object-box, will be found to answer the purpose; but if a more rapid process is required, we may, as proposed by Mr. Moule, use the Bengal lights, which contain a large quantity of the actinic rays. These lights are composed of six parts of nitre, two of sulphur, and one of the sulphuret of antimony. The powder is made up in the shape of a cone, which is ignited at the top; but it would be better to spread it out widely, in order that it may be condensed upon the object-box. The lime-ball light may also be employed, but the Bude light, which is a coal-gas flame, rendered more intensely luminous by a stream of oxygen, is preferable to any other artificial flame. In using it, or any other of the lights already mentioned, for obtaining Kaleidoscope figures, it must either be placed very near the object-box, or condensed upon it by a large lens, on account of the small size of the aperture at the eye-end of the Kaleidoscope. 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 1 See the Journal of the Photographic Society, vol. iv. p. 137. 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 THE splendid discoveries which have been made with the telescope and microscope have invested them with a philosophical character which can never be attached to any other instrument. It is only, however, in the hands of the astronomer and naturalist that they are consecrated to the great objects of science; their ordinary possessors employ them solely as instruments of amusement, and it is singular to remark how soon they lose their novelty and interest when devoted to this inferior purpose. The solar microscope, the camera obscura, and the magic lantern, are equally shortlived in their powers of entertainment; and even the wonders of the electrical and galvanic apparatus are called forth, at long intervals, for the occasional purposes of instructing the young, or astonishing the ignorant. A serenity of sky very uncommon in our northern climate, is absolutely necessary for displaying the powers of some of the preceding instruments; and the effects of the rest can only be exhibited after much previous preparation. From these causes, but principally from a want of variety in their exhibitions, they have constantly failed to excite, in ordinary minds, that intense and continued interest which might have been expected from the ingenuity of their construction and the splendour of their effects. The pleasure which is derived from the use of musical instruments is of a different kind, and far more intense in its effects, and more general in its influence than that which is obtained from any of the preceding instruments. There are, indeed, few minds that are not alive to the soothing and exhilarating influence of musical sounds, or that do not associate them with the dearest and most tender sympathies of our nature. But the ear is not the only avenue to the heart; and though sorrow and distress are represented by notes of a deep and solemn character, and happiness and gaiety by more light and playful tones, the same kind of feelings may also be excited by the exhibition of dark and gloomy colours, and by the display of bright and aërial tints. The association, indeed, is not so powerful in the one case as in the other, for we have been taught from our infancy, in consequence of the connexion of music and poetry, to associate particular sentiments with particular sounds; but there can be no doubt that the association of colour is naturally as powerful as that of sound, and that a person who has never listened to any other music but that of nature, nor seen any other colours but those of the material world, might have his feelings as powerfully excited through the medium of the eye as through that of the ear. The first person who attempted to supply the organ of vision with the luxuries of light and colour, was Father Castel, a learned Jesuit, who had distinguished himself chiefly by his opposition to the splendid optical discoveries of Newton. About the year 1725 or 1726, he published in |