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410 The PHOTOGRAPHIC news. [June 29, 1883. It may be of interest, in view of Mr. Jabez Hughes’ reference to ‘‘Moser’s images” as a possible explanation of the phenomena detailed by Captain Abney in his paper on “ The Effect of Pressure on Sensitive Salts of Silver,” to recall some of the experiments of Moser in support of his theory. In one, a silver plate, having been iodised during the night and in complete darkness, an engraved agate medal and a horn ring were placed upon the plate, which was afterwards subjected to the mercurial vapour, when perfectly distinct images of the figures engraved on the agate and ring were developed. This experiment was repeated by Encke, the astronomer, in the presence of Humboldt, when an ornamental engraved plate was placed upon a highly-polished silver plate, which had not been iodized, and left during the space of twenty minutes ; the image was but indistinctly represented on the plate, but became more perfect by iodising the plate, and subjecting it to mercury. The “ discovery,” however, which caused the most sensation, was the statement by Moser that the same effect was produced in complete darkness when the objects were not in contact; or, to use Moser’s own words, “ When two bodies are sufficiently near each other, they imprint their images respectively one on the other.” It is rather singular that the phenomena which Moser announced in 1842 as a new and original discovery, and afterwards brought before the British Association in 1843 by Pro fessor Benil, Dr. J. W. Draper made public in 1840, a fact which the American scientist did not fail to point out to the British Association. Moser appears to have been something of a fanciful philosopher. He had, for instance, an ingenious theory of the action of mercury; knowing that the yellow ray had the property of continuing the effect commenced by light on iodide of silver, he supposed that a yellow latent light was given out by mercury when in vapour. It slightly upset the theory, however, when Claudet showed that the surface of the silver plate, when analysed, disclosed the presence of mercury. On this theory Mr. Robert Hunt wrote: “ The speculations of M. Moser are too purely hypothetical to be admitted in explanation ofthe phenomena observed. Indeed, his doctrine of latent, or, as he calls it, ‘ invisible light,’ involves some absurdities.” How long are photographers usually in sending out proofs? Of the six studios we have recently visited, one sent no proof at all, but executed half the order in a week; a second studio sent us a proof in four days, a third (untoned) in five days, a fourth in six days, a fifth in eight days, and the sixth studio kept us eleven days waiting. Another point in statistics may be noted as the result of our visits. In all six cases was payment demanded and obtained at the time of sitting. In three instances the money was paid after posing, and in the other three, before hand. Chloride of calcium as a means of drying and absorbing moisture has been used from the earliest days by photo graphers. But it is only comparatively recently that the price of this compound has become so low that its em ployment in large quantities for common purposes has been within the reach of all classes. At present this useful desiccating medium is obtainable wholesale at from £4 to £5 a ton, and for this reason we cannot help think ing photographers may find a still wider application for it. Calcium chloride has found a limited application in the drying of gelatine plates, for one thing, and is likely to be more extensively used for that purpose in future. Patent Entelligence. Application for Letters Patent. 3062. Charles Denton Abel, of 28, Southampton Buildings, Chancery Lane, in the county of Middlesex, for an invention of “Improvements in apparatus for producing intense white light.”—A communication to him from abroad by Charles Clamond, of Paris, France.--Dated 20th June, 1883. 2G77. Alexander Melville Clark, of the firm of A. M. and W. Cl irk, of 53, Chancery Lane, in the county of Middlesex, Fellow of the Institute of Patent Agents, for an invention of “ Improvements in and in apparatus for changing and storing photographers’ backgrounds and other movable scenery.”— A communication to him from abroad by William Evans Lindop, of St. Thomas, in the province of Ontario and dominion of Canada.—Dated 30th May, 1883. 2680. Carl Daniel Ekman, of Sweden, but now of 57}, Old Broad Street, in the City of London, Chemist, for an invention of “ Improvements in the extraction of gelatine, fat, and similar substances from bones, hides, fish, and other animal matter.” Dated 30th May, 1883. Grant of Provisional Protection. ’ 2799. Joseph Julius Sachs, of Gray’s Inn Road, in the coanty of Middlesex, for an invention of “ Improvements in appa ratus to be used in the preparation of metal surfaces for etch ing, engraving, and similar purposes.”—Dated Sth June, 1883. Notices to Proceed. 896. John Rudolph Meihe, of 2, Laurence Pountney Hill, in the city of London, for an invention of “ Improvements in the production of printing plates or blocks by photographip means.”—A communication to him from abroad by Julius Allgeyer and Carl Bolhoevener, persons resident at Munich, in the kingdom of Bavaria.—Dated 19th February, 1883. Patents Granted in Belgium. 61,421. C. Cros and A. Vergeraud, of Paris, for “Positive Paper for Photography.”—Dated 19th May, 1883.—French Patent, 14th November, 1882. Patent Granted in Sweden. 165. O. W. Wicklund, for “ An instantaneous emulsion for photography.”—Dated 31st May, 1882. Patents Granted in Prance. Certificate of Addition. 146,702. Olive, for “Funeral mounts for photographs.”—Dated 18th December, 1882. Class 20. Specifications Published during the Week. 5283. W. Kennedy, “ Translucent plates or sheets for use as substitutes for glass in roof lights, &c.” My said invention has for its object the production of im proved translucent plates, or sheets, to be used as substitutes for glass in roof-lights and otherwise. My improved plates or sheets will not transmit so much light as clear glass, but will allow as much to pass as will be sufficient for many purposes and for various situations ; whilst they will not be so easily broken as glass, and will be of less weight than glass of the thickness con sidered necessary for roof lights. My improved translucent plates or sheets consist of perforated sheet zinc, or of any suit able perforated sheet metal, or of wire gauze, the openings through which are closed with gelatine, varnish, or other suitable translucent substance or composition. Or sheets of paper or of woven fabric may be cemented or otherwise attached to the per-