The photographic news

• Bandzählung: 35.1891
• Erscheinungsdatum: 1891
• 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-id1780948042-189100009
• PURL: http://digital.slub-dresden.de/id1780948042-18910000
• OAI: oai:de:slub-dresden:db:id-1780948042-18910000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

308 THE PHOTOGRAPHIC NEWS. [APRIL 17, 1891. arbor of which a wheel is set provided with ratchet teeth. This wheel sets the pin free at any desired interval by means of ratchet teeth provided on its periphery engaging with the pin of the lever. 17,284. Oct. 31st, 1889.—“ An Instrument for Demonstrating Astronomical Phenomena.” John George Parvin, of 12, Duncombe Road, Hornsey Rise. This invention is intended to be used for indicating the position in the heavens of any planet, and of the moon, and fixed stars, at what hour the same will rise, pass the meridian, and set. It will also indicate the phases of the moon, and when lunar eclipses will take place. It consists of a disc on which are drawn a series of concentric circles divided and inscribed appropriately. Upon the said disc, and attached thereto by guides working on its edge, or otherwise attached so that it may be made to revolve concentrically with the first disc, is a second and smaller disc, on the outer edge of which is a circle divided into twenty-four hours and subdivisions, and in the central part of which, within the said circle, but not concentric therewith, is an opening of such size and shape as to represent the horizon of the place in which the apparatus is intended to be used, say, for instance, London. This disc is capable of being rotated on the first or larger disc, so that the two may be made to assume or pass through any desired relative radial positions, so as to show through the said opening the fixed stars drawn on the first disc visible at any given time. At the centre of the first disc is attached one, two, or more indexes or pointers so arranged that it, or they, or either of them may be set to any required point or points, and preferably so arranged at the centre that they may be moved a limited dis tance in the direction of their length and on the said pointer or pointers. Attached to each is a small knob or indicator that may be moved either with, or independently of, the pointer towards or from the centre, and set at any required distance ; it is better to use two pointers, and make one of them “earth ” and the other one “ planet.” On the first-named—that is to say, the larger disc—is inscribed a series of circles divided and marked as follows, but the order of the circles need not be that stated below, as it may be varied considerably without departing from the invention. The outer circle of the said disc is divided and numbered to represent right ascension ; the next inwards may be marked with the corresponding signs of the zodiac ; then may come an annular space over which the hour circle, forming part of the second disc, lies ; further inwards may be a circle, or circles, re presenting the division of the year into months and their sub divisions into days. On the space within these circles are represented some of the principal fixed stars, or so many of them as are within the zodiac. If preferred, the right ascension circle may be placed nearer the centre and within the lines representing the zodiac among the fixed stars. By setting the pointer marked ‘ 1 earth ” to the day of the month, and the pointer marked “ planet” to the right ascen sion of any planet, and setting the indicator on the planet pointer to the planet’s declination, and then moving the apparatus so that the indicator on the planet hand is brought over the eastern portion of the horizon, the time of the rising of the planet is indicated by the pointer on the hour circle, and in the same way the time of its meridian passage and its setting may be obtained, and its position among the fixed stars. At a meeting of the Deutsche Oesellschaft on Fre-unden der Photographie, Prof. Rietschel sent a ground-glass plate which, it is stated, was made by flowing the glass with a milk emulsion (a mixture of gelatine and milk). West London Photographic Society.—At the meeting held at Broadway Lecture Hall, Hammersmith, on April 10th, Mr. W. A. Brown in the chair, slides by the following members were shown :—Messrs. Bennett, Chang, Dixon, Hodges, Kellow, Lamley, H. Selby, L. Selby, Varden, Whitear, C. Whiting, and H. F. Wilson. Correspondence. LONDON AND PROVINCIAL PHOTOGRAPHIC ASSOCIATION. Sir,—Will you allow me again to call the attention of those of your readers interested, to the fact that this Association is still taking steps to enlarge its library. So far the Society has been helped in this endeavour by the presentation of works bearing on photography from many friends, as well as a considerable number of volumes from members. While feeling greatly indebted to those who have already been so generous, the members still think that there are numerous well-wishers who, when once they know of the existence of the wants of the library, would hasten to forward gifts of photo graphic literature for that purpose. Parcels of such, or single volumes, will be gladly received and acknowledged if forwarded to the Hon. Secretary, Champion Hotel, Aldersgate Street; or to Mr. F. W. Pask, Hon. Librarian, Leyton House, High Street, Leyton. THE QUAGGA. Sir,—Some time ago I advertised in different newspapers in districts of this colony and Bechuanaland re the quagga. I mean the districts where he was likely to be found. I have also sent photos of the quagga wherever I thought I could get information. This brought me a host of correspondence from Mashonaland, Bechuanaland, Namaqualand, and the colony. One of the most important letters I have forwarded to Mr. Bartlett. I learn with disappointment that the quagga is extinct in the lower parts of the colony, but my correspondent, who evidently has studied colonial natural history, and knows what he is writing about, has advised me to write to Namaqualand, where they are said to run over the immense sandy flats of that country. I wrote to two parties, one of which thought there would be no difficulty in getting one or two young ones. I have been careful to point out to them the difference between the quagga and the zebra. The quagga is undoubtedly, from what I learn, a distinct species, and very vicious. When wounded they will turn on anything, and tear limb from limb. The letter sent to Mr. Bartlett gives a detailed account of the life and manners of the quagga, which would be too long to insert here. Namaqualand is a long way from here. I expect to have another letter in, say, three weeks from now. Should I suc ceed in procuring one, it is my intention to have him brought down to Prieska. I could then go there myself and arrange to bring him on here. We frequently have waggons here from Prieska. It is about a fortnight’s ride from Kimberley. I am very hopeful of success. B. Harvey. Kimberley, March ‘iind. P.S.—I omitted to state in my letter, giving a description of the modus operandi in photographing by the wet process at the Zoo, that the bath had a slight addition of potass, nitras. Old workers on interiors will know the why and wherefore. The plate was also backed with a thick pad of wet blotting- paper. M. LIPPMANN’S DISCOVERY. Sir,—As I was the first to raise, in your paper, a doubt— since fully justified by the presidential address delivered at the Camera Club Conference—allow me now a small space in it to close the subject of the so-called discovery of photography in natural colours by a few practical conclusions. I have strong reasons to believe that: (1) two plates sensi tised by Prof. Lippmann’s process, and exposed, one to the spectrum and another to an orange transparent glass, will give the same result of rainbow hues under identical treatment as to development and time of exposure ; (2) that a blue or yellow glass screen will not produce a blue or yellow negative by re flection ; (3) that the effect is most likely due to the extreme delicacy and transparency of support, as collodion or albumen, and not to the sensitiveness of the film.