The motion picture projectionist (Nov 1931-Jan 1933)

40 Motion Picture Projectionist November, 1931 Known and used the World Around MORE than 15,000 Griswold Film Splicers are in constant daily use throughout the world. For years the perfect splice has been made with a Griswold. Griswold is the standard film splicer for efficiency, durability and economy. GRISWOLD MACHINE WORKS Port Jefferson, L. I. New York Universal Film Splicing Machine A MODEL NO. 3 Pat March 22:22 First-Class Results on New or Old Film Permanent Gauge No Adjusting FOR THEATRES, EXCHANGES LABORATORIES, SCHOOLS Price $6.00 GENERAL MACHINE CO., INC. 816-826 East 140th St., NEW YORK, N. Y. For sale by all Supply Dealers Mellaphone All-Electric Theatre Amplifier Eliminates "A" and "B" batteries, charging and amplifying equipment. Complete control of power supply for exciter lamp and photo electric cells. Complete amplification control. Perfect filter, no hum. Tone improved. A compact unit I5y2" sq. 13" deep. 110 or 220 volt. 50-60 cycle. Write or wire for full information MELLAPHONE CORP. ROCHESTER, N. T. MELLAPHONE All-Electric Theatre Amplifier Two Mellaphone Sound Heads, one Mellaphone All-Electric Theatre Amplifier and Stage Speakers complete Sound Installation. studios and theatres are also coming closer each day to the engineer. Each group can be of greater help to the other. The engineer can explain the reason for the equipment design to the technician, can bring out the fine points of its utilization, and can anticipate and cure the troubles which may arise in its daily use. The technician, on the other hand, can present to the engineer a multitude of practical problems of daily routine which require ingenuity for their engineering solution. He can make most valuable criticisms and suggestions. "These groups should and must come closer together, and it is to be hoped that the Society of Motion Picture Engineers will contact directly with the technicians of the industry with this aim in view. I shall not touch further on the tasks of the Society in the immediate future, particularly since they have been so clearly outlined to you in President Crabtree's opening address. Stress Cooperation "I wish only to emphasize, in more general terms, that we shall all work together in this Society to bring more science into the field of motion pictures and, by this means, greater effectiveness, increased acceptance of the product by the public, and a continually higher status of the motion picture industries. We have this privilege of working for the growth of. that agency, science, which was so well described in the inscription on the dome of the building of the National Academy of Sciences in Washington, where it is stated: 'To science, pilot of industry, conqueror of disease, multiplier of the harvest, explorer of the universe, revealer of Nature's law, eternal guide to truth.' Gentlemen, with this aim in view, your officers will endeavor to carry forward the work of their able predecessors during the coming year." Theory and Fundamentals (Continued from page 29) the secondary impedance (Zs) is only 10 ohms. This change in impedance has occurred as can be seen, only through the use of the 4 to 1 ratio transformer. If, for example, the impedance (Zs) were a loudspeaker and the generator were a vacuum tube, the 4 to 1 ratio transformer would cause the 10 ohm speaker to represent a 160 ohm load, it can be said to be the equivalent impedance of the 10 ohm speaker load expressed in terms of primary of the transformer. Knowing the behavior of the transformer as explained above the equiv