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682 THE PHOTOGRAPHIC NEWS. [OcTOBER 23, 1885. motionless in the air—an enormous liquid iceberg of crystal clearness and dazzling white surmounted by pinnacles of foam ; and at this moment, it is reported that the click caused by the discharge of the drop-shutters belonging to the army of photographers present was dis tinctly heard at a distance of five miles I Down came the torrent, collapsing into mountainous waves, and in a moment it was seen that the success of the operation was complete (and off ran all the photographers to develop their plates, and very pleased we shall be to see some of their results). How to restore plates to usefulness after they have once been exposed—or, in other words, how to obliterate the latent image—is a problem which we thought had been solved by the use of a bath of potassium bichromate, followed by a copious washing. C. Glissenti has, however, tried numerous other chemicals—apparently selected at random—and among those which he finds to answer well are five per cent, solutions of formic acid, jyrophosphate of soda, sulphate of ammonia, sulphate of soda, nitrate of ammonia, and chloride of ammonium. It is difficult to understand why some of these should obliterate the latent image. 20 atent ntelligence. Applications for Letters Patent. 12,227. Walter Griffiths, 139, Belgrave Street, Highgate, Birmingham, for “ Improvements in photographic plate boxes.”—14th October, 1885. 10,533. Arnold ROcHOLI, 8, Quality Court, London, for “Improvements in photograph stands.”—5th September, 1885. 10,594. John Rudolph Gotz, 19, Buckingham Street, Adelphi, W.C., for “Improvements in or connected with photographic cameras.”—8th September, 1885. 12,374. Thomas Samuels, 53, Chancery Lane, London, for “ Improvements in apparatus for holding dry plates or films, and for changing them in the photographic camera.”.—16th October, 1885. 12,474. Edward Slater, 6, Lord Street, Liverpool, for “ Im provements in and relating to photographs.”—18th October, 1885. Patent Sealed. 13,103. Ludwig Hermann Phillippi, 55, Chancery • Lane, London, for “ Improvements in reproducing photographs by printing, and in producing printing blocks or rollers therefor.” —Dated 2nd October, 1884. Patent which has become Void through Non payment of the Fourth Year’s Renewal Fee. 3014. G. Smith.—“ Photographic cameras, &c.” Patent Granted in America. 327,778. William G. ENTREKIN, Philadelphia, Pa. “ Photo graph burnishing machine.”—Filed April 10th, 1885. (No model.) Claim.—I. The combination of the burnishing-roll and its bearings, with a petticoat enveloping the lower portion of the said roll, and hung to the shaft of the same, so as to be thrown to one side or the other to expose the roll, as set forth. 2. The combination of the frame, the upper and lower rolls, the pins, the spur-wheel on the lower roll, and the locking segment, as set forth. 3. The combination of the frame, the upper and lower rolls, a spur-wheel hung to the frame, a spur-wheel secured to the spindle of one of the rolls, and a spr-wheel held in place on the spindle of the other roll by means of a thumb-nut in the end of the spindle, as set forth. PHOTOGRAPHIC APPARATUS AT THE ENGLISH PATENT OFFICE. BY CHAPMAN JONES.* Camera Backs. Changing boxes, roller slides, and matters connected especially with focussing screens and cloths, besides methods of screening a part of the sensitive surface, and plate-holders which are also baths, or allow of immersing the plate in a bith connected with the camera, will be separately dealt with. The simplest method of focussing is by moving the focussing screen, tor a movement of the lens changes its distance from the object,as well as the distance betweenit and the plate-holder. The camera described by M. Berry (August 14, 1839), as used by-Daguerre and Niepce, had a back that moved along the baseboard, and could be secured where desired by a thumb-screw and nut; and A. J. F. Claudet (December 18, 1841) applies a rack-and-pinion for moving the back. W. Lawley and H. S. Starnes (December 21, 1881) have a back that slides to and fro within .the camera, so that the camera body extends behind the back, an arrangement that exists in many of the old forms of cameras. A. J. F. Claudet (December 18, 1841) makes the Daguerreotype plate-holder to slide vertically on a rod with a screw to fix it in the suitable position. He does not state what advantage is gained by having this adjustment, but doubtless it was simply to get the picture well on the plate, the movement being an exact equivalent for a vertically sliding front. A. Ceileur (February 21, 1863) describes a plate-holder that slides vertically and horizon tally, and is provided with the necessary stops, so that different parts of the plate may in turn be brought behind the opening of a screen that determines the size of the picture. He mentions one hundred small, or two dozen large pictures on the same plate. (Note.—25 pictures, each 6} by 43, would require a plate 32} inches by 232 inches.) H. du Moot (June 8, 1861) and T. A. Dillon (March 18, 1879) both have a long frame that holds a number of dry plates; Dillon’s is moved by clockworkfor automatically copying a series of documents, &c. The effects of a swing-back seem to have been first pro vided for by J. C. Bourne (March 27, 1855) by a compli cated and uncertain movement of the front, which has already been described. H. E. Palmer (November 26, 1856) has a back that slides for focussing inside the camera body, and the plate-holder is supported on two horizontal pins, like a swing looking-glass, and has curved guide pieces at the top and bottom. H. Macfrlane (November 17, 1860) says that the benefit of a slight inclination of the picture plate is “ well understood by photographers.” He makes the back part of a sliding body camera to enter the front part only a little way, and attaches it thereto by a pin at the top, and another at the bottom, so obtaininga slight movement about the vertical axis. A vertical swing is got by having a pair of movable rests, against which the plate frame bears. W. J. Stillman (November 14, 1871) rounds the bottom edge of the back, and supports it in a hollowed shoe, in which it can be fixed by a screw at any inclination. Vertical swings are also provided for by W. B. Woodbury (April 27, 1877, and S. W. Rouch, April 11, 1878). G. Smith (July 8, 1881) secures the back to the base-board by a single screw, which allows of both a vertical and horizontal swing simultaneously, and re quires only the one screw tightening to fix the back in any position. The back turns, hinge fashion, on a horizontal pin in the top of the screw, and the screw itself, passing through the base-board, is the vertical pivot. He also describes variations of a ball-and-socket joint for giving the universal motion to the back, and fixing it by one screw only. G. Hare (June 27, 1882) hinges the back frame on the base-board, and fixes it at the required inclination by * Continued from p. 619.