The Optical Magic Lantern Journal (July 1889)

14 The Optical Magic Lantera J ournal and Photographic Enlargor. and bottom, in which the slides can travel. They are always entered at one end and taken out at the other. | As they are generally made exactly 9? inches long, it ; is evident that if three slides are in the holder the mid@le will be exactly centred if the two outer ones are exactly adjusted to either end, which is quite easily done by the finger of each hand. Practically, there are never three at once. The first one has to take its chance, unless the operator takes the precaution of adjusting it before the lens is uncovered. A very common occurrence is the neglecting it ; then the slide | is jigged backwards and forwards on the screen to get it centred, and it augurs very badly for the rest of the show, and so it well may, for it is very likely that two thin slides will happen to follow one another, and instead of the second one pushing the other before it, it will slide over it and possibly jamb in the groove. Who has not frequently seen exhibitors perform this trick, at places too where better things were expected ? One spring in the upper groove in preference, made to press towards the condensers in the centre of the | holder, and two similar springs in the lower groove, one in the centre and the other just about half an inch from the entering end. This end, by the way, should have the back part of the wall of one of the grooves cut away, top or bottom at will, but not both. for more easy entering of the slide. If the springs are not too strong they will be quite noiseless ; they are best made of watch spring. To fit these in the groove a fine diagonal cut is made with a saw in the wall of the groove, not much thicker than the spring to be in| serted. A little hard spirit varnish dropped in will ; hold it firmly. A somewhat wider cut must be made in the opposite diagonal direction to take the free end. | The springs may be from 2$ inches to 3 inches long, and the cuts made to suit, but the fixed end had better be towards the entering end of the holder. _In the first case—the holder without springs—the pictures are rarely in focus, the slides have too much play in the grooves, which are usually unnecessarily wide, and therefore a thin one will not unfrequently be much out of perpendicular; the result is that the audience is quite exhausted in less than an hour. In the second case, with the same holder, fitted with | springs, the effect is better and less noticed by the ; audience, but the change must be made quite slowly | and regularly, as well as stopping exactly in the centre of the screen, or the spectators will rise. GEORGE SMITH. Photography as Applied to the, Lantern. DURING tbe past few years, the number of those who interest themselves in the lantern and its capabilities has been vastly increased by the sudden popularity of the art of photography. Amateur photographers are now to be found in every town in the kingdom, and : they are beginning to find out that there is no better method of showing their friends the pictures which they have taken than by means of the optical lantern. The same instrument, too, as it offers a means of | making permanent enlarged copies of small photo| graphs, serves with them a double purpose. T. C. HEPWorRTH (Book of the Lantern). | Novel Dissolving Effect. Wirurn a circle of, say, 9 inches diameter a swan is drawn with indian ink, and shaded to represent the ordinary bird, water and the surrounding scenery being also sketched in. The paper is left white on all portions which are to be coloured or left transparent. Two transparencies are next taken of the usual lantern slide size. Colour the sky, water, scenery and beak of one slide appropriately, and paint the plumage and the reflection in the water black; and in the other slide stop out all but the bird and reflection. When the first picture is shewn on the screen the swan will appear black ; and when the second lantern, containing the other slide, is turned on, the plumage will gradually become white, whilst the scenery will not undergo any change. P. Editorial Table. Messrs. SAMUEL Fry & Co. have introduced some novel forms of transparency frames. They are made in all sizes, from lantern upwards, and are constructed to hold either one or a series of views. In one kind the picture is held by the action of a screw, and in another variety by means of spiral springs. The whole thing is neat and effective, and is sold at a moderate ‘price. Being nickel-plated it possesses advantages over lacquered frames. As a means of placing or suspending one or more lantern slides in a window, they will be very useful. A NOVEL instrument (the Faciometer) for measuring a persen for spectacles has just been brought out. _ By applying it to the face, and adjusting various screws, the exact relation of the eyes to the nose, and width of temples, are shown upon a scale. The agents for this country are Messrs. Sharland, Thavies Inn, London. WE have received from Messrs. Bemrose and Sons, Chetwynd Street, Derby, a folio of Collotypes, comprising specimens of portraiture, landscapes, and examples of work for commercial illustrations or art catalogues. They are all that can be desired. Applications for Patents, 1889. No. 3719.—March 2, T. Howell, “ Improvements in illusion devices." No. 3818.—March 5, W. Leach, “ Improvements in the stage, which is used as a part of his lantern microscope, known as Leach’s Oxyhydrogen Lantern Microscope.” No. 3966.—March 6, A. T. Clarkson, “ Improvements in telescopes.” No. 5114.—March 25, J. Greenbyry, “ Improved apparatus for displaying photographs or cards." No. 5430.—March 29, C. Lantz, “A new and improved apparatus for automatically exhibiting pictures and the like upon receipt of a coin.” No. §542.—April 1, A. R. Wormald, “ An improved stand, or frame, for exhibiting photographic lantern slides, | negatives, or other transparencies.” No. 6999.—April 26, C. Gray and H. Kemp, “ Tmprovements in magic lanterns.” —