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746 THE PHOTOGRAPHIC NEWS. [November 23, 1883. shutter. The drop portion of the shutter is caused to fall over the aperture by means of an india-rubber band or its equivalent, so that the aperture is closed by such time as the flap has moved through about five-sixths of its distance, thus all shaking of the lens is obviated during the time of exposure of the plate. The flap is retained closed over the aperture by means of a suitable catch ; on this being released, the flap instantaneously rises in the manner hereinbefore described, followed immediately by the falling of the drop. And in order that our invention may be the more completely understood, reference is given to the accompany ing drawings and to the letters and marks thereon. description of drawing.—The figure is a vertical section showing the‘flap’ raised and the ‘drop’ lowered covering the aperture, a is the frame or body of the shutter, b is the drop fitted so as to slide freely in the frame, c is the flap carried on the spindle mounted in bearings attached to the frame. On Claim.—1. The combination of the layers and strips Abeg one end of the spindle is provided an adjustable box containing a coiled spring, such spring having one end attached to the box, and the other to the spindle. The object of this arrangement is for the purpose of raising the flap c when required, and the rapidity of such move ment may be increased or reduced at pleasure by turning the box containing the spring round, and thereby tighten ing or slackening the spring. The spring box is held in any required position by a pin ; the pin, when in this position, projects through the flange of the spring box, and rests against the front part of the flame a. The flap c is retained over the circular aperture I by means of a suitable catch m, or its equivalent; on this being released, the flap instantane ously rises into the position shown in the figure. The drop b is caused to fall over the aperture I by means of the india-rubber band n or its equivalent, such band n being arranged and applied in the manner shown in the drawings, and its strength is varied to suit the rapidity of the motion required. The stop r, which may be covered with an elastic ring, serves to arrest and cushion the fall of the drop b against the boss of the flap c. We find in practice that the aperture I should be covered by the drop b, by such time as the flap e has moved through five-sixths of its distance, all shaking of the lens being thereby obviated during the time of exposure of .the plate. In order to prevent the drop rebounding after it has descended into the position shown in the figure, we secure a light spring to the side of the frame, and to the lower end of which is attached a pin, which passes through the side of the frame, and pro jects slightly as shown beyond the slide. After the drop has closed over the aperture I, the pin passes into a recess provided for it in the drop b, and retains the latter in position. Having now described the nature of our said invention, what we claim is—The general arrangement and combination of the various parts forming the shutter for instantaneous photography, and mere modifications of the same, substantially as and for pur poses herein set forth. Patents Granted in America. 287,857. G. FRANK E. PEARSALL, Brooklyn, N. Y., “ Photo graphic dry-plate holder.”—Filed May 24th, 1883. No model. with a slide, G, and a cover, h, so that the sensitive plate can be introduced and secured at one end and the slide G at the other end, substantially as and for the purposes described. 2. In combina tion with an envelope for a sensitive plate provided with a slide G, substantially as described, the combination of a rubber strip, d, arranged, substantially as described, to form a close contact with the slide G while being inserted or removed, and with the inside of cover h when the slide is out. 3. In an envelope or holder for sensitive dry plates, the construction and combination of the side strips, ec, provided with the recessess or notches f f, acting in conj unction with the elastic rubber strip d and slide G, substanti ally as and for the purposes described. 287,858. Henry B. PEunY, Chicago, Ill. “Pneumatic shutter for photographic cameras.” Filed Feb. 17, 1883. No model. Claim.—The combination of the frame A, slides B B, having stud b', links B', and lever C, with the cylinder D, having piston d connected to the lever, and the air-bulb E and its tube e, all constructed and arranged to operate substantially as and for the purpose set forth. 288,025. James B. Colt, New York, N.Y., assignor of one-half to Sidney C. Thompson, same place. “Device for focussing lenses.” Filed September 17, 1883. No model. Claim.—1. Lens-tubes A and A', corrugated with screw-thread a spun thereon, in combination with lenses fixed into said tubes, as and for the purpose described. 2. Lens-tubes with spun cor rugated screw-threads, a, and recesses, d, in combination wi lenses fitted in said recesses, as and for the purpose described:ria 287,938. FRIEDRIOH CARL Hosch, Nuremberg, bavars Germany. “ Process of photo-mechanical printing in co