The Optical Magic Lantern Journal (June 1897)

96 The Optical Magic Lantern Journal and Photographic Enlarger. negative film. The film from the negative supply reel is carried along over the sensitive film reel and both pass in contact, in continuous motion, under an exposing chamber illuminated by white light, either incandescent, electric light, or a Welsbach gas light, thence over the toothed sprocket driving wheel to the winding reels, the exposed film being wound first. It will be noticed that the reels are interchangeable, hence to make duplicate copies it is only necessary to remove the negative spool from the winding up end to the supply spool standard of the apparatus and begin over again. The perforations in the edges of the film are of specially square shape and give the squitre sprocket teeth of the propelling pulley a better pull on the film. The teeth pass through the perforations of both films, causing both to move exactly the same, and at all times to keep in perfect register. The speed of the film passing under the exposing chamber must be uniform, and this is obtained by propelling the sprocket wheel by an electric motor or by a spring motor. The electric motor is geen behind the light chamber in the larger of the two engravings. The axle of the motor has worm gear operating a cog wheel on the main shaft. The V shaped elastic band holds the frame (in which is a ground glass) in contact with the films, producing a sort of tension on the film. To the left of the light chamber is a supplementary tension, adjusted by screw nuts, as shown. Referring to the diagram illustration will be seen two slotted diaphragm cards. These are placed over the ground glass just mentioned, at the bottom of the light chamber, and are for the purpose of regulating the amount of light that acts on the negative. If the negative film, as a whole, should be thin, then the card with the narrow slot is used, which allows a shorter exposure to be made, as the negative and film are passed under it. If the negative is full of density, then the narrow card is removed and the wider slotted card substituted, which allows a larger volume of light to act upon the negative film. The exposed film is wound around large open reels from its spool, and developed by passing through troughs of developer solutions. The necessity of providing apparatus to quickly reproduce positive impressions from the negative ribbon films is one of the reasons why this simple device was invented, and its novelty consists in the fact that the film moves continuously under a uniform source of light without any intermittent motion or the use of shutters. The operation of exposing the film ig carried on in a room illuminated by the usual ruby red light.— Sci, Amer, Prominent Men in the Lantern World. No. VIII.—Mr. A. R. SCHUTZ. Ca eee subject of our sketch is one of the active members of the British Astronomical Association, who, in the course of his teachings and lectures, employs the lantern to a great extent. His name, doubtless, oR” suggests a foreign origin, so we may as well state that he was ‘made in Germany,” on a small scale, fifty-two years ago, he having been born on a farm on the Photo by W.C. Bristow] i Worthing. Westerwald, in the Province of Nassau—then a dukedom. His forefathers being well-to-do agriculturists on the one hand, and a long line of clergy on the other, young Mr. Schutz got a good national education as well as a good drilling in ploughing, sowing, and reaping. Small holdings in Germany are somewhat uncertain, and after a few bad crops and the cattle plague, they often get split up, and eventually pass into other hands. The farm in