The Optical Magic Lantern Journal (December 1899)

160 The Optical Magic Lantern Journal.and Photographic Enlarger. bridge rising from each end comes to a point in the centre resembling an inverted V. The angle however is not so acute, in fact it is so obtuse that given a bridge of say 4 inches in length the rise in the centre would not be more than half-an-inch. The bridge crosses almost the entire width of the picture, and as it stands in the track of caravans, we wish if possible to represent it at the exact moment that a train of laden camels is passing across. If we paint the camels upon a slip of glass they disappear as they near the centre of the bridge, being hidden by the rise in the parapet, therefore a straight slipping glass will not give us the effect we wish to obtain. We may if is true tilt the guide upon which the glass runs, but in that case the camels would continue ascending and would not descend on the other side of the bridge. It is clear that to cause our camels to change the direction of their path after passing the apex of the bridge they must be painted upon some substance, or mounted in such a manner that the procession is flexible and not rigid, as is usually the case. No such substance being known to us at present, we must overcome the difficulty by mechanical means. The whole of the machinery is laid out in Fig. XX XIX. We see that it consists essentially of a wooden frame of suitable size, in the centre of also one-eighth of an inch in thickness, and round these wheels and across the top of the wooden block passes a tightly stretched endless band composed of the strongest kind of tape. To facilitate its working the top of the wooden block is not only made very smooth, but is carefully coated with powdered blacklead. On this band are rivetted a number of small squares of mica, which overlap each other to prevent any blank space intervening when the procession is bent as it passes over the point in the centre of the bridge. On each of these pieces of mica is painted a camel, and on reference to our diagram the method of moving the whole arrangement will be at once apparent. To keep all the various portions in their places a plate of glass is then placed over the whole, as shown by the dotted lines in our illustration. One of the most ingenious mechanical motions ever applied to the production of optical effects upon the screen was exhibited in connection with an entertainment founded upon Weber's opera of ‘ Der Freyschutz.” Those Fig. XXXIX. which is cut a round hole 8 inches in diameter, this being filled by a circular glass; and this glass is blacked entirely over, with the exception of a small portion left clear to show the train of camels. On the top of this, in the position shown in our diagram, is screwed a thin piece of hard wood, the upper edge of which is cut to the exact shape of the parapet of the bridge in our foundation picture. This is about one-eighth of an inch in thickness, and is extended aa a guide along which the flexible train of camels is to pass. At either end of this piece of hard wood, very close to it but not quite touching, are large wooden wheels acquainted with this opera will remember the thrilling and dramatic incantation scene, in the course of which the magic bullets are cast. At each casting the light from the brazier changed colour, and a variety of weird and grotesque apparitions appeared floating in the air, seated upon the rocks, and crawling upon the ground. ‘The most natural of these appearances was a wriggling serpent, which contorted its body in an extremely realistic manner, and which entering on the left side of the picture crawled across the foreground and disappeared upon the right. “This remarkable piece of mechanism is now in possession of the writer, and will be found illustrated at Fig. XL. It bears a certain family resemblance to Fig. XXXIX., as the actual painted portion is drawn upon small plates of mica. The usual framework of wood contains a square brass plate, shown by the blacked out portion of our diagram. In the