The Optical Magic Lantern Journal (April 1896)

ee ee = The Optical Magic Lantern Journal and Photographic Enlarger. 73 communications as desired, and remove superfluous gases in certain processes, more especially in obtaining oxygen from atmospheric air, 5136. 7th March, 1896. L. Chapman. Improvements in air and gas compressing pumps. RECENTLY-PRINTED SPECIFICATIONS. Copies of the following specifications may be obtained by remitting 1/for each specification to The Patent Depart ment, ‘' Dptical Magic Lantern Journal," 9, Carthusian Street, London, E.C. 6468 of 1895. Fitzpatrial (Fuhrmann). Dioramas. 7104 of 1895. Selle. Producing coloured pictures. 6545 of 1895. Davenport. Arc lamps. 6777 of 1895. Gearing. Acetylene generating and storing apparatus. Edwards. Photochromoecope. Schachinger. Producing indelible pictures on glass. Picking. Producing engravings, etc., on glass. Decretet & Lejeune. Rossbach-Rousset. 3613 of 1895. 6602 of 1895. 6790 of 1895. 16502 of 1895. Acetylene. 1116 of 1896. Acetylene gas. ——:0:—-— Editorial Table. ““MopgRN Microscopy,'' London: Balliere, Tindall & Cox, 21, King William Street, Strand, W.C. 3s.6s. This handsomely bound volume, which is devoted for the most part to beginners, is a dual production from the pens of Mr. M. I. Cross, and Mr. Martin J. Cole. The former treating in a masterly manner of the microscope as an instrument, and giving details of its various portions and the parts they play; the latter writer gives information upon the preparation and mounting of objects. The reader will find from cover to cover that each page creates a new interest, and ere many pages have been digested he who does not posseas a microscope will see the advantages that are obtainabe from the possession of one. ‘‘ INTENSITY CorLs.'"— Amateurs desirous of experimenting in connection with X and other rays, will do well to peruse a book called ‘‘ Intensity Coils," published at 1s. by Messrs. Perken, Son, and Rayment, 99, Hatton Garden, London, E.C. In its 80 pages many subjects are to be found, which will tend to the profitable passing of an occasional hour. SurpFs oF SouTH AFRIca.—A set of 60 slides relative to Kaffirs, Boers and Britains, in South Africa, being a story of British enterprise in the Dark Continent, with the thrilling account of Jameson's Dash to the Transvaal, has been brought out by Mr. Walter Tyler, of Waterlooroad. The set being very exhaustive, and showing native life in different aspects, will be sure to have an enormous run, 0: Correspondence. CARBON LANTERN SLIDES. To the Editor. Srr,—In an article in your last issue, by Mr. Duncan Moore, on the best kind of lantern slides, I think that carbon transparencies should have been included in the number ; for, in my opinion, in which I am backed up by many skilful lanternists, carbon tissue will give us slides of unexceptionable quality, and of any colour. The pigments in the tissue, made expressly for transparencies, are in such &n extremely fine state of division that granularity is quite imperceptible with the largest degree of amplification ever likely to be required. The late Mr. Smith, of the Sciopticon Company, was | fucile princeps in the manufacture of lantern slides by this process, and was especially happy in the results he regularly obtained ; in fact, when his slides were shown in comparison with those by other processes, they were considered quite as good, if not better, than the beat examples obtained by cevelopment in the ordinary manner—albumen films being the nearest approach to it for quality. Then, again, carbon can be made any colour. The nature of the image is such that it consists of different thicknesses of the same colour, the highest lights being bare glass; thus rendering the successful application of any dye an easy matter, as, although the tint may be altered, the gradations remain constant, which is more than can be said of most other processes. A great variety of effects can for this reason be easily produced. Inmany casesa colour not being approved can be removed, and another substituted, as almost any liquid that will stain can be applied—Aniline dyes, ink, permanganate of potash, ammonic sulphate of copper, etc. For instance, a slide darkened with ink can be restored tu its original condition by a bath of dilute hydrochloric acid, and soon; but setting aside colour possibilities, the ‘richness of a carbon image cannot be improved upun. Should we wish to reproduce a negative, we adopt a carbon transparency as the best medium for this purpose, as being far better than any other kind of image. Experienced photographers can testify that there is that peculiar quality in a carbon image that, although somewhat difficult to describe, is readily appreciated ; doing away with all barshness, especially when there are strong and abrupt contrasts of light and shade on the negatives to be copied. A reproduced negative, with this intermediary, is sometimes better than the original ; very rarely, if ever, the case with any other process. So far as pure photographic quality is concerned, it is my opinion that if carbon work was better known t> amateurs it would become the process for transparency work of nearly all kinds. It is simple in the extreme—not much more trouble than ferro-prussiate printing—a basin of hot water and a little alum comprising the whole of the requirements when the tissue is purchased ready sensitised, and when not, the only additional things are a little ammonia and bichromate of potash to make the sensitising bath. With 80 much to recommend it, and so few drawbacks, it is somewhat difficult to understand why it is not more generally used. S. BROWN. —— os LANTERN SLIDE EXCHANGE. To the Editor. S1r,—Will you kindly grant me space to say to those whom it may concern that I propose to close the ‘‘TLantern Slide Exchange’’ at the end of the present season, it having I think, fulfilled its purpose. I, however, will keep the set of lists by me, and I shall always : be ready, on receipt of a post-card, to forward it on to any of the present members who may desire, on some future Occasion, to make use of it. Various communications have shown me that the Exchange has been of considerable benefit to many of the members, and no