The Optical Magic Lantern Journal (April 1896)

69 and soon. Although the gauge does not show the number of feet in cylinder, this may be easily ascertained, as the reader will perceive from the last sentence. If the lantern outfit is to be complete, a screen to project the picture upon, and a frame to stretch it, should be purchased. Linen is the best cloth for the sheet as it reflects the greatest amount of light. Calico is the next best. For house exhibitions 8 ft. or 9 ft. is a convenient size, and square sheets of these dimensions may be had ready taped and without seams for 9s. (calico), and 24s. (linen). In the larger sizes the sheets are in two pieces, joined with wide width in centre. The frame to stretch the screen upon is rather an expensive luxury; for the above sizes of sheets it costs from 16s. to 30s. A much cheaper and quite as effective frame, is that one which I described in this journal for February, 1895. In the 8 ft. size it costs 5s., an enormous saving on the commercial article. Directions for the making of other cheap frames have also been given very frequently in this journal. When the sheet and frame do not require to he carried about, the style of screen will be found convenient, which is mounted on rollers and supplied with cords, so that it can be rolled up out of the way when not in use. As this device combines sheet and frame, it costs slightly more than the price of either, but less than the price of both. For holding the slides in the proper position in front of the condenser of the lantern, a ‘‘carrier’’ ig employed; there are many forms of carriers. The best, I think, and the one most used is the ‘‘ to and fro”’ kind. Although this has disadvantages, it works smoothly and noiselessly, which the more complicated patent dissolving carriers do not always do. One variety of this carrier has the corners cut off, which allows the slides to be inserted or withdrawn by merely touching the corners, and not fingering the centres as in the simpler kind of carrier. This carrier has also been designed to raise the slide as it is withdrawn from the lantern stage. The fingering of the slides is also avoided in this species. Davenport's patent curtain slide carrier gives the effect on the screen of an opaque curtain descending to obscure the picture, and rising again to reveal afresh one. It is made in two varieties—for use in open stages, and for use in any stage. The former costs 5s., the latter 7s. 6d. The price of the ‘‘ to and fro”’ pattern is about 2s. The other forms of carriers are too numerous to describe; let it suffice to mention them :—Beard’s (two kinds), Hughes’, i ‘Push Through or Panoramic,” “ Universal Dissolving,” ‘‘ Uno Mano,” and many others. The general size for lantern slides is 32 in. by 34 in. They are sometimes mounted in mahogany frames, but in this condition are not suitable for use in a single lantern, as the clumsiness and difficulty of changing such would be tiresome both to operator and audience. For use in the single lantern, unmounted slides are placed in the carriers already referred to, and thus pass smoothly in and out of the instrument without the unsightly whiteness on the screen. It would be difficult to name a subject upon which lantern slides cannot be had. Kven life in prison is depicted so graphically to an audience, who sit in comfortable, cushioned seats, that they begin to feel like the convicts themselves in their dingy cells. Travel, history, biography, science, subjects sacred and secular, all furnish some interesting views reproduced by the aid of photography. The usual price of plain photos is Is., or coloured, 28. each. When a set of slides is purchased, a reading to describe them is also to be had asa rule. The lecturer would do much better to compose a lecture to suit the slides, and entertain his audience, than read a prosy, printed book, every second minute attracting attention by his efforts to turn a page. Should the lecturer, however, require to read his lecture, or refer to his notes, a reading lamp must be used, for any attempt to read in the darkness of the lantern exhibition-room would be futile. Stands are made to support the manuscript, but may be dispensed with if a table is available. Reading lamps vary in cost from 2s. to 10s. The method of communication between the lecturer and operator is often very defective. When it is necessary to change a slide the lecturer sometimes gives aclick from a ‘‘ distinette”’ or a redlight signal from the lamp, but more often by a harsh knock or resounding bell. These methods all attract attention. A noiseless—so far as the audience is concerned—electric signal should be employed as a means of communication between platform and lantern. Instructions regarding the manufacture of one of these signals may be seen in the Optican Maaic LANTERN JouRNAL for January last. A ready reference table, for showing the distance the lantern should be placed from the screen to give a disc of a certain size with a lens of a certain focus, may be had for 24d. at the office of this journal, and will be found handy. The Macic Lantern JourRnat will, of course, be taken by every right-minded lanternist, and will undoubtedly prove a great help.