The Optical Magic Lantern Journal (November 1899)

154 The Optical Magic Lantern Journal and Photographic Enlarger. What would you think of a conjuror if he, say, borrowed a silk hat from one of the audience, and after showing it perfectly empty, produced a real egg from it, if you saw him put the egg into it? You would say he was no conjuror, and rightly too; and yet you would feel hurt if told you were no lanternist. Don’t misunderstand me, however. I make no claim for effects on account of any ‘‘ magic” there may ke about them, for these things are now not the secrets they once were, although there are yet millions in these islands who do not know how these changes are produced ; but what I claim is, that as Nature herself is charming, so a reproduction of Nature is charming, in accordance with the degree of perfection attained. Next we will proceed to consider our lantern and slides. The lantern may be a bi-unial, as long as we are content to use only those effects which both commence and finish with a single slide, so as not to break the continuity of dissolving, and which never require more than two lanterns to be going at once. Actually very few sets fulfil these conditions, especially tke former; so that, with a bi-unial, we are almost entirely restricted to what I may term ‘“sequence ”’ slides, z.¢., night following day, and soon. So that, all things considered, a triple is to be preferred. A lengthy dissertation on the technicalities of the triple lantern need not be entered into here. It will suffice to say that ‘it should be light without being cramped, strong without being clumsy, well-made without being complicated, high-class without being expensive. Wealthy amateurs have from time to time had lanterns built to order regardless of expense, and loaded with every mechanical device ever evolved from the brain of man or the genius of the brass finisher, only to find that they were too heavy to be moved, like Robinson Crusoe’s first canoe, and too intricate for practical work; and in the end, have been glad to get rid of them at a fraction of their original cost. About a lantern a few things are necessaries, one or two more are conveniences, and all the rest are superfluities. Included in the first named are the registering runners with which the stages must be fitted. “Strips of brass” are sometimes suggested and often used for this purpose, but a “strip of brass” generally implies a piece cut from a sheet of yellow metal ; what is needed for a runner is a gun-metal casting, properly designed and accurately finished. The top face of the runner should be three-eighths of an inch wide, and dead square to the condenser block; each end should be adjustable as to height by means of a screw, and the side of the stage away from the operator should be furnished with an adjustable stop to prevent the slides being entered too far, and the position of this stop isa point requiring attention. In many lanterns it is attached to the condenser block in the middle of the height, where, not only is if in the way of any slipping or panorama glass which has to pass beyond its frame, often only having the end of a glass slip to butt against ; but, in the case of an ordinary slide block, it butts against a piece of mahogany nearly twoinches wide, of which the grain is vertical, and it can easily be understood that, any swelling or shrinkage of this piece after the slide is registered will throw the whole picture out. The proper place for this stop, therefore, is on the top of the runner itself, where end grain will meet it in every case. It need not be of any great height, a mere heel a quarter of an inch high is ample ; slipping glasses, panoramas, and other movements will then pass clear of it. Sometimes it is made to turn out of the way, but this is very rarely necessary, besides which, any swivelling arrangement of this kind prevents the stop being firm enough for our purpose. It should be adjustable, and this adjustment and those of the runner should be capable of being locked after being set. If preferred, the runner and stop of the middle lantern may be made fixtures in their correct positions, those in the top and bottom lanterns being adjusted to them in every case. Many lanterns are now made with condenser blocks of brass, instead of mahogany, as has been usual for so many years, and runners, specially adapted for fixing to this class of lantern, are shown in Figs. J. and II. They are fairly simple, and can easily be made by Ss R iss s of Fig. I. Fig. II. anyone possessing a few tools, and what is most important, the ability to turn out accurate work. Fig. I. shows the runner for the middle lantern. It is permanently fixed in its correct position, and parallel to the baseboard, by two countersunk screws, ss, driven from the inside