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The photographic news
- Bandzählung
- 29.1885
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- 1885
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- Bandzählung
- No. 1379, February 6, 1885
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The photographic news
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Band 29.1885
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- Register Index III
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90 THE PHOTOGRAPHIC NEWS. [FEBRVARY 6, 1885. provements in photographic printing and in apparatus there for.”—Dated 31st January, 1885. Patents Sealed. 912. Robert GALLAUD - Mason, of Hambleton House, Promenade, Douglas, Isle of Man, Schoolmaster, for “ An instrument to be called the 1 micro-photoscope.’ ”—Dated 8th January, 1884. Specifications Published during the Week. 3510. Henry Bratt Sharp, of No. 5, South John Street, Liverpool, in the County of Lancaster, Optician, for “ Im provements in portable legs, supports, or standards for the stands for cameras, stereoscopes, telescopes, theodolites, music, easels, surveyors’ staffs, and other like purposes.”—Dated 18th February, 1884. The claim appears to consist in the use of the spiral or portable walking stick in making tripods or other supports. The spiral walking-stick, as our readers are probably aware, consists of a strip of thin steel wound into a spiral like a paper spill, and secured by a cap at the larger end. Such a leg can be compressed into a length corresponding to the width of the steel, or can be drawn out to three feet or more; and the length can be adjusted within a considerable range; but the steel spiral is very easily damaged by careless handling or rough usage. Patent Granted in America. 811,057. Richard Brown, Robert W. Barnes, and Joseph Bell, Liverpool, County of Lancaster, England. “Method of preparing pictures and photographs for photo-engraving.’’— Filed Aug. 1, 1883. (Specimens). Patented in England March 15, 1883, No. 1380, and in France, April 21, 1883, No. 155,029. See Photographic News, 1883, p. 602, and 1884, p. 218. THE PREPARATION OF HYDROCHLORIDE OF HYDROXYLAMINE. BY ARNOLD SPILLER.* At a recent Technical Meeting of the Society, the subject of the preparation of hyroxylamine salts was discussed, and in conse quence of some of the members not succeeding with preparations of their own, I was requested by the Chairman to communicate to this journal full details of the mode of manufacture. In now complying with the request, 1 wish it to be understood that as the operations are somewhat difficult and dangerous, I should strongly advise those who have little or no knowledge of chemical manipulation to be content with the commercial product. The method which I am about to describe was devised by Dr. Divers, and depends on the formation of hydroxylamine hydrochloride by the direct action of hydrochloric acid on mer cury fulminate. For the following details my best thanks are due to Dr. H. Foster Morley, M.A., who also sent me two excellent specimens of bis own preparation. To prepare the fulminate, place 160 grams of metallic mer cury (quick silver) in a large beaker or other convenient vessel, and then pour in a mixture of 1,600 grams of strong nitric acid (sp. gr. 112), and 320 cubic centimetres of water. The vessel is gently heated on a sand-bath, in the open air, till the whole of the metal is dissolved. The beaker containing the warm liquor is taken off the heating bath, and 1,600 grams of methylated spirit are mixed with 160 c.c. of water, and half the mixture poured directly into the mercury solution. In a few minutes the liquid will begin to boil with the evolution of red fumes ; the rest of the spirit should then be poured in, when the red fumes will give way to white clouds, and, at the same time, a black precipitate will be formed. The whole mixture is now left to stand over night—still out of doors—when it will be found that half the liquid has boiled away, and that a heavy compound consisting of mercuric fulminate is produced. The liquor is next poured away, and the vessel filled up with water. After the sediment has settled, the liquid is again poured off, and this process of washing by decantation repeated. To obtain hydroxylamine from the fulminate, the latter is rinsed into a porcelain evaporating dish, the water drained off, and 160 grams of pure hydrochloric acid (sp. gr. 1’17) poured over it. The whole is evaporated to a small bulk out of doors, as the fumes of prussic acid which are evolved are very poisonous. When the liquid is reduced to about one-third its original volume, it is diluted with about 500 c.c. of cold water, and then * Read before the Photographic Society of Great Britain. sulphuretted hydrogen passed through till the whole of the mercury is precipitated as sulphide. The liquid, after filtration, is evaporated to dryness in a dish over a saucepan of boiling water, and the residue of the hydrochloride of hydroxylamine, if required of special purity, may be crystallized from methylated spirit. The latter operation is, I think, hardly necessary for photographic purposes, as any slight impurities would not seriously interfere with the process of development. The following tests for identifying hydroxylamine compounds and the impurities liable to be met with in commercial products may be of value. Caustic soda or potash blackens silver chloride or bromide in the presence of hydroxylamine. Fehling solution.—Alkaline cupric tartrate forms, with hydro xylamine, in the cold, a red precipitate. Tincture of iodine is decolorized by hydroxylamine. Hydroxy lamine compounds boiled with solution of caustic potash or soda yield ammonia. The chief impurity present in commercial hydrochloride is ammonium chloride ; this may be identified by stirring a few drops of saturated solution of the compound in a watch-glass with a little alcoholic solution of platinic chloride, when lines of crystals formed at the points of friction are the result. ON THE RAPID PRINTING PAPER. BY LEON WARNERKE.* The rapid printing paper I intend to describe this evening meets a great want, felt especially in these dark winter days, to print from a negative, rapidly and quite independent ly of the time of day, or of daylight. Paper of this kind is quite new as regards its manufacture, having been introduced only quite recently, but the principle involved in its manufacture is not new ; it has been already introduced before this Society, and two years ago it was shown to illustrate a Cantor lecture at the Society of Arts, by Captain Abney. Eder and Pizzighelli fully describe it in tbeir book on “Gelatino-Chloride.” Notwithstanding this being a well- known process, it had not found any practical application until the firm of Messrs. Marion and Co., with their usual energy and enterprise, offered to the public paper of this description. The necessity for this article appears to be so urgent, that in no longer time than a fortnight afterwards several other manu facturers also announced the production of rapid printing paper. The new printing paper is produced by covering white paper of the finest quality with sensitive gelatine emulsion. Like for many other photographic processes, only the finest quality of paper can be utilised, which must be as textureless as possible. I find that 10 kilo. Saxe photographic paper is perhaps the best for the purpose. As regards the emulsion, chloride of silver answers very well, also it may be modified by the addition of other salts of silver, such as bromide, iodide, oxalate, citrate, and others ; however, as vigorous black tones are of importance, chloride of silver will be found to be the best base. Only very colourless gelatine must be used, in order to preserve the white ness of the paper. The spreading of the emulsion on the paper in one uniform homogeneous layer is not an easy matter. Special machinery must be used to produce it on a large scale, but for amateur use, when only a small quantity of the paper is required, it is dipped in hot water to drive all air bubbles from 'the pores ; it is then squeezeed to the glass plate, previously levelled on a stand, and a suitable quantity of the emulsion is poured on. As soon as the emulsion is set, the paper can be taken off and arranged for drying, either by hanging or otherwise, or it may be dried whilst on the glass. The temperature of the room must be taken into consideration during coating, as if cold the glass plate must be warmed. The addition of glycerine to the emulsion will prevent cockling of the paper if the atmosphere is too dry. Paper prepared with emulsion can be kept a very long time before it is used, if preserved from light and damp. For print ing, it is put behind the negative in the printing-frame, the same as albumenized paper, and exposed to the light; but from this point all the manipulations become different from the usual practice. The image produced by the action of light is gener ally invisible, and consequently practice and experience alone will dictate the length of exposure. Either daylight or artificial light may be used for printing, and the time of exposure will also depend upon the density and colour of the negative. A few seconds’ exposure to diffused daylight, or about thirty seconds at
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