The Optical Magic Lantern Journal (October 1889)

40 Selections. LANTERN-SLIDE making is growing to be one of the most fascinating branches of photography, being easier and more satisfactory to do than silver printing.—?. C. Beach. * * To any person having a knowledge of the development of dry plates, success in makin transparencies is guaranteed if he would only obtain a dozen dry plates. quarter size, of any standard make and patiently experiment with them upon one subject.—#dnard Viles. s * * IT is found in practice, when enlarging considerably the subject copied, that it is much more effective to focus by moving the said object to and from the lens, than to focus in the ordinary way by altering the back of the camera.—/2. Z/. Preston, : a * In copying engravings, woodcuts, &c., the lines given by the engraver are very often, when magnified to a large size, too conspicuous on the sheet, and I have seen some things exhibited which, when on the screen, looked like one of the flaming posters on the walls and hoardings that are now so frequen'ly seen announcing the various performances of the day.—T. Gulliver. ** . x SorT varieties of lime may be used with advantage for the oxy-calcium lamp ; but only hard lime should be employed for the oxy-hydrogen jet. This lime is formed into the shapes required, usually into cylinders, and these are put into bottles afd sealed up so as to preserve them from the action of the atmosphere.—4. A. Wood. e ew Witt ordinary care and attention the limelight is easily managed, and by its means the lantern becomes in the hands of an intelligent photographer a means of profit and enter tainment unthought of a few years ago.— William Hanson. * * IT may not be generally known that a thoroughly gas-tight connection can be immediately made between an_ indiarubber tube and metal pipe. Having pushed on the indiarubber tube to a sufficient distance, it is only necessary to roll back the front part of it.—Eaward Viles. * THE brain needs no training to see erect with an inverted image, because it is a physical fact that an image projected through a convex lens is inverted—the reason for placing slides in a magic lantern upside down.—Author of * The Philosophy of Sight.’ * * * THE lantern season is at hand, and we may make the “winter of our discontent ” a “ glorious summer" by making slides.— Geo. Wheeler, * * THE sine gua non of a lantern slide is that it shall be absolutely clear in the high lights.— W. Bishop, x %* DAGUERRE had made his reputation as a painter of panoramas, and was well-known in connection with his efforts to improve dioramic effects long before he announced his discovery of the Daguerreotypic process.— C. E. Pearce. > +____ Brass LacQuer.—A beautiful gilding may be given to brass and bronze by a lacquer composed as follows :— Rectified spirit, three hundred and thirty-two parts ; shellac, Sixteen parts ; dragon's blood, four parts ; turnseric root, one part. The metal intended to be lacquered is warmed, and the varnish applied by means of a brush or sponge. The solution should be kept in a stoppered bottle. The Optical Magio Lantern Journal and Photographio Enlarger. Notes and Queries. B.—The slides have been returned to the owner. feared they were rather too coarse. Garrett, J.—We replied to your query in our last issue. Chromotrope asks if it would be safe to use house gas in conjunction with compressed oxygen, when a mixed jet is used. Alnsve.—No ; better employ a blow-through jet. W. C. Cook writes to say that he has tried the use of ground glass, as recommended by Mr. Alfred Watkins, in the September number of this journal, and is well pleased with the results; ‘but,’ he adds, ‘‘it must be very finely ground, otherwise the sketch has a rough appearance when exhibited on a screen.” Opal.—If you return the spoiled cards to Mr. Friese Greene, he will send you good ones in exchange, without extra charge. Aupraxiscope asks how Mr. Muybridge changes his pictures (of animals in motion) upon the screen. Are they one basis with moveable parts, or are they a series of pictures? Reply.—The figures are placed in consecutive order near the rim of a circular plate of glass; another plate of glass is placed parallel to the first. This second disc is opaque all but a number of clear lines, radiating from the centre. When the two discs are rotated rapidly in opposite directions, the apparent size of the figures becomes diminished, and instead of seeing a procession of animals in different attitudes, the idea is conveyed that the same image is assuming various positions. If, Lacy asks, ‘‘What is a polytropochromaticon?™” Ansiver.—lIt is similar to a kaleidoscope, and it is used with coloured substances, such as broken glass. Lh. Farrant.—There is no necessity to have two sets of pressure boards. Why not make one suffice, by placing the gas-bags one over the other? One set of weights will then do. But if gas is laid on at the hall, why not use it instead of hydrogen ? NV. /.—No. 4 on your list will answer your purpose better than No. 2; but as you say you intend being in London ina few weeks, postpone purchasing until then, when you can call upon the firm and inspect the various styles. We shall be glad tosee you. Thanks for your good wishes. Smell of Oil.—See our issue of June 15th, pages 3 and 4. Trade,—Write to Messrs. York and Son. They have lately produced the Paris set about which you enquire. Sobu writes :—“TI have a very old quarter-plate photographic portrait lens. mounted in wood, which I am desirous of converting into a lens for a magic lantern, so as to shew a disc four or five feet in diameter. Can this be done, and how? The lens is the usual double combination.” Tteply.—The lens described is the same as those now universally employed with but few exceptions. It will require no alteration, unless a brass tube besubstituted for the wooden one. We have received the catalogue of Mr. Underhill, Croydon, which contains particulars of a variety of slides. 2B. W.—We cannot offer an opinion on the data mentioned. ‘Wiss 1f.—The slide sent is very creditable, but the foliage is rather darkly coloured ; a little picking out would be advantageous. A.W, S.—Thanks for particulars. W. ».—(1) We will send copies to the persons mentioned. Thanks for the interest yon take on behalf of this journal. (2) There is no difference in the illumination between the two classes of lenses, the difference, if’ such exists, being in their defining properties. A Subscriber (Greystones).—There is no place here where the Sczentific American can be purchased, but special numbers may be ordered through Trubner and Co.,* Ludgate Hill, London. The number inquired about is that for the week ending May 11, 1889. Bull’s-Eye—The ‘‘ Flashes” came too late for this issue. We