The photographic news

• Bandzählung: 6.1862
• Erscheinungsdatum: 1862
• Sprache: Englisch
• Signatur: F 135
• Vorlage: Hochschule für Grafik und Buchkunst Leipzig
• Digitalisat: Hochschule für Grafik und Buchkunst Leipzig
• Digitalisat: SLUB Dresden
• Rechtehinweis: Public Domain Mark 1.0
• URN: urn:nbn:de:bsz:14-db-id1780948042-186200003
• PURL: http://digital.slub-dresden.de/id1780948042-18620000
• OAI: oai:de:slub-dresden:db:id-1780948042-18620000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Bemerkung: Seite 1-72 fehlen in der Vorlage. Vorlagebedingter Textverlust.
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

222 THE PHOTOGRAPHIC NEWS. [May 9,1862. of silver, contains both the above nitrites of silver. The liquid has the following properties :—When boiled down by itself it gives off a small quantity of nitric oxide gas, then fuses and yields a yellow sublimate. The mass treated with water, when cold, yields nitrate of silver, and leaves a mix ture of metallic silver and a yellow powder. The yellow solution oxidises when exposed to the air, and deposits crystals of nitrate ; the same result is produced by heating it with nitric acid, the liquid being then decolorised, and giving off nitric oxide gas. Hydrochloric acid added to the liquid, throws down white chloride of silver. Ammonia pre cipitates black pulverulent silver, and retains oxide of silver in solution. Potash forms a brown precipitate of suboxide of silver, which is converted into the protoxide on exposure to the air, but if immediately dissolved in cold dilute nitric acid, again gives a black precipitate with ammonia. Cold water added to the yellow liquid throws down the yellow basic nitrite ; but on dropping the yellow liquid into boil ing water, the precipitate changes colour from yellow to red, and is then converted into black metallic silver, which forms a specular' deposit on the sides of the vessel. So long as the precipitate remains yellow or red, it disappears on the addi tion of nitric acid ; but after it has become black, nitric acid no longer dissolves it. Alcohol, likewise, throws down the yellow powder, and the liquid filtered from it leaves on evaporation a residue of nitrate of silver and metallic silver. Tincture of sulphate of indigo is decolorised by the yellow liquid with precipitation of silver. Nitrite of silver is also formed when nitrate of silver is heated for some time above its fusing point: it is certain that some of this salt is formed when nitrate of silver is fused in the ordinary process of preparing the fused nitrate; and it is probable that the increased intensity noticed when fused nitrate is used in preference to the crystallised salt, is due to the presence of a small quantity of nitrite. If the presence of any nitrite be suspected in the nitrate of silver, and it be desired to be got rid of, the best plan is to boil an aqueous solution of the fused salt with a little pure nitric acid, and then evaporate down on a water bath. The nitrous acid is driven off by the nitric acid, and the slight excess of the latter remaining with the dry nitrate after evaporating down, may be removed by heating it just short of its fusing point. Nitrite of silver is capable of forming a double salt with potash and soda. The potash salt is obtained by adding nitrite of potash in excess to nitrite of silver, and evapo rating over sulphuric acid. It forms yellowish rhombic crystals, which are permanent in the air. • Uhe Unternational Gxhibition. PHOTOGRAPHY. The contributions to Class XIV., “Photographic Apparatus and Photography,” are, so far as we can glean from the present incomplete arrangements, scattered over something like five-and-twenty different places in the building. The number of contributors, so far as we can gather from the not very perfect official catalogue, is nearly four hundred. Of the number of pictures contributed, it is still more diffi cult to form an estimate, as the catalogue affords no indica tion whatever, all the contributions of each person being included under one number, without any intimation whether that number embraces one or twenty pictures. From a roughly-made calculation, we judge there are not less than two thousand frames, some of these including many pictures. In the British department there are about one hundred and fifty-six contributors, and of these about thirty-six exhibit apparatus and chemicals, leaving one hundred and twenty as exhibitors of pictures. It is somewhat singular that this is just the number of exhibitors at the last exhibi tion of the Photographic Society. The number of pictures now exhibited, or, rather, frames of pictures, is between eight and nine hundred: the number at the last exhib. tion of the Society was six hundred and twenty-two. 01 the quality of the pictures now exhibited it would be fair at present to make any remark, as the glasses are ft the most part covered with a thick coat of dust, whidl renders any correct judgment impossible. The departmenl is indeed, at present, incomplete; and workmen are still engaged in connection with it. An awning has to be erected over the glass roof, but not in immediate contad with it: this will lessen the glare of heat and light, and with some ventilating arrangements, will, we trust, make the apartment more tolerable. Cases of apparatus, &c., and stands of stereoscopes, which are at present enveloped U linen covers, will then be displayed, and the apartment being put in order, fair description and criticism will be possible. Already, as we anticipated, Mr. Breese’s mool, light pictures are exciting much discussion, and a bet d fifty pounds to a farthing was recently offered, on the qu, tion of their genuineness. We have reason to believe ths the question will engage the careful attention of the jurors io this department, and will, we doubt not, issue in confirmin' our convictions, expressed nearly twelve months ago, of N Breese’s perfect good faith in using the term, “phot graphs by moonlight.” As we have stated, the catalogues give no informatiol as to the number of pictures forwarded by each contr butor, and, as necessarily follows, no clue to the subject, apd little guidance as to the process; and as the various pi tures of the same contributor are not all hung together-' the exigencies of the space demanding that they should be arranged so as to fit—the task of examining and co" 1 ' paring the pictures will require care and attention. We intend, as far as possible, when everything is in order, to make our description and criticisms serve to some extent • a hand-book to the various photographic collections. In the French department, which is not yet, however completed, the catalogue gives a list of about one hundred and eighteen exhibitors, of which twenty-eight contribute apparatus and chemicals. The pictures, or frames of pit tures already hung, are between four and five hundred. Tb 1 ' number of contributors at the last French Exhibition, il Paris, were upwards of one hundred and sixty, sendin§ upwards of one thousand three hundred pictures. Tbe space devoted to photography in the French department is so far as we can judge without actual measurement, abot twice as large as the especial room devoted to British pho tography, and much more conveniently arranged, being s long gallery, admitting of a series of small transvem screens, each of which are, in many instances, devoted to a single contributor. Life-size pictures, by the sols’ camera, and as described in some instances, taken direct form an important feature in this department, frot their number and excellence. Some carbon prints ao some enamels, by Carmarsac, are especially good. Sot’ exquisite photographs on white silk, with ample margip showing as well by transmitted as by reflected light, an curious and beautiful. Amongst the finest landscapes in the French department are those of our countryman, F. Max; well Lyte, who figures in the catalogue as “ Maxwell, L Some large instantaneous pictures of shipping, water an! clouds, by M. Varnod, of Havre, are unsurpassed, 1 equalled, by anything we have seen. , Canada sends some very good pictures: the once Enitel States none, so far as we can ascertain. Rome sends veC fine large architectural subjects. Spain nothing. Of otbe contributors in Continental Europe, we may mention Be gium, Denmark, Austria, Bavaria, Prussia, Saxony, Greec! Italy, Norway, Portugal, Russia, Sweden, Switzerland, 82 amongst British colonies, and other foreign countries, W may mention India, New South Wales, Tasmania, Jense Natal, Brazil, &c. Some of these are not yet hung, and noC we believe, quite completed; we will, however, give edc detailed attention in due course. on We may mention another noticeable feature in connectio M with stano illust half the e “trot exhib grou count cond Wore illust surpr full a This Guild being Tuesi Barol Tli taker emin and s tiff oi tion deter Tl form, the . phiot pose Talli the J then: M serv for t the i M No < arise inti sent. The as a; duct aM[ flail h>tl Patt that sobs verc tion in “ an whi cho to a an: it,l Chi ren ven ma pas tut “P api Qu tai SOI an th, de