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THE PHOTOGRAPHIC NEWS. Vol. XXIX. No. 1399.—June 26, 1885. CONTENTS. Variation in the Price of Metals during the Past Ten Years ... 401 vamavon 111 LUU Inee • — O 20: Rapidly Printing Stippled Tracings from Photographs 401 The Antwerp International Exhibition 402 Another Block Process. By George Sutherland, M.A 403 How to Succeed in Taking Good Pictures on Gelatine Plates. By S. R. Bottone 404 “Poor Pussy.” By Percy De Vere 405 Photographic Reminiscences of a Journey from London to Rome. By George E. Thompson 406 Royal Cornwall Polytechnic Society, Falmouth 407 PAGE I Notes 40S । Patent Intelligence 409 A Scamper Across a Continent with a Camera. By R. G. Brook 410 . Photo-Lithography and Photo-Zincography. By Major J. Waterhouse, S.C 411 i Correspondence 413 Proceedings of Societies 413 Talk in the Studio 416 Answers to Correspondents—Photographs Registered 41G ranks Osmium Iridium Gold ... Platinum Thallium Magnesium Potassium Silver ... Aluminium Cobalt ... Sodium Nickel ... Bismuth Cadmium Quicksilver Tin Copper ... Arsenic Antimony Lead ... Zinc Steel ... Bar iron Pig iron RAPIDLY PRINTING STIPPLED TRACINGS FROM PHOTOGRAPHS. Stencil printing for writings or fine work is a thing which has only come into use during the past few years, and it was first introduced by Edison in connection with his electric pen. In the pen of Edison a fine needle point is made to move very rapidly up and down by means of a minute electric motor attached to the instrument; and if one writes with this pen on a sheet of paper the lines will be made up of numerous clear perforations packed quite closely together, and the perforated sheet of paper thus obtained may be used as a stencil for printing a very large number of copies. For this purpose the stencil is laid on a sheet of paper, and either a roller or squeezes charged with printing ink is passed over it. If now an ordinary print upon albumenized paper is used as the basis of the stencil, the person working with the perforating pen can very readily follow the outlines of the subject, and also work in a great deal of the light and shade, in this way obtaining a stencil from which numerous copies can be rapidly printed. Since the introduction of the electric pen various per forating methods have been devised, some of which in volve the use of far less complex and delicate appliances than the electric motor pen of Edison, and among these may be mentioned the trypograph of Zuccato, in which the paper to be perforated is laid on a fine file, and the tracing is perforated with a blunt steel point or stylus, the teeth of the file cutting their way through the paper. As, however, it is difficult to ensure that the file shall always be exactly underneath the part of the photograph which is being traced, there is some advantage in using a perforating pen rather than the file underneath ; and a recent invention of Mr. G. Gestetner seems likely to prove of considerable value as a simple and economical substi tute fo rthe electric pen. It consists of a minute spur wheel, mounted at the end of a pencil shank; and to make the printing stencil, this is rolled with some pressure on the outlines and shaded portions of the photograph, this > print being by preference laid on a sheet of zinc or other VARIATION IN THE PRICE OF METALS DURING THE PAST TEN YEARS. In the current number of the Journal of the Society of Arts there is an interesting table showing the market cost of some twenty metals in 1874, and again in 1884. Owing to the progress made in the technical details of extraction and reduction, the general tendency has been towards a lowering of the value of metals ; but in some cases the cheapening is due to increased supply, as in the case of silver. Silver, according to the table, has fallen in value no less than ten shillings per pound during the past decade; but it is certain that photographers do not enjoy a proportionate reduction in the price of the nitrate. increase its strength and durability. The normal standards of the metrical system are made of platinum-iridium on account of its known immutability. In 1882, platinum stood 15 per cent, below its present value ; but its increased employment for industrial purposes led to the subsequent improvement in price. Thallium has experienced a severe depreciation, on account of the economical process by which it is extracted from the residue of the lead chambers used in the manufacture of sulphuric acid. The use of this Gold, according to the authority quoted, now highest in value of all metals, the competition of osmium and iridium having been overcome. It is only by reason of improved methods of preparation that the latter have become cheaper, while their use has at the same time in creased. Iridium is mixed with platinum in order to metal is mainly confined to experimental purposes. The fall in silver has arisen from increased production anti diminished use for coinage. The price of magnesium is, as will be noticed, given as being now 35s. a pound, or (say) 2s. 3d. per ounce ; and mention is made of it being turned out at this low figure from a factory at Salindres, but we have not yet heard that it can be bought in London at a rate much less than that charged ten yearsago. The value of cheap magne sium to the photographer, especially in the winter months, need not be enlarged upon. Boo. 1874. perlb. Dac. 1884. per lb. E s. d. £ s. d. 71 10 o .. 62 0 0 70 0 0 45 0 0 62 15 o .. 63 0 0 25 7 6 .. 21 7 6 23 17 6 .. 4 15 0 10 5 0 .. 1 15 0 5 0 0 .. 4 0 0 3 17 6 .. .(In Hamburg) 3 7 6 1 16 0 . 1 16 0 1 1L 0 . ... 1 2 0 0 14 2 . 0 8 8 0 11 0 . 0 8 1 0 8 1 . •• . 0 8 1 0 7 1 . . 0 4 0 0 2 0 . . (in London) 0 1 9 0 0 1 0 10} (in Berlin) { 0 0 0 0 9 7 0 0 8 . .. ••• •• . 0 0 44 0 0 6} " 0 0 5 0 0 2 - (in Berlin) • 0 0 K 0 0 24 o 0 14 0 0 0 0 0 0 1, It 0. 1 (in Upper , Silesia 0 0 0 0 0 0 0, 0 0i