The motion picture projectionist (Nov 1929-Oct 1930)

28 The Motion Picture Projectionist January, 1 930 Method of recording with the four-element mercury arc the mercury arc shows in his U. S. Patent No. 1,654,951 of January 3, 1928, a method in which a fourelement mercury arc may be used us a recording tube. From a careful examination of the circuit described in this patent, one can readily see that it ought to give ideal results. In this circuit we see the A. C. source at 8 fed into the primary, 9, of a transformer; one of the secondary windings, 9', feeds the anode, 10, of the mercury vapor tube, 11, through the resistance, 12. A second secondary winding, 9' ', supplies the potential for the plate of the electron tube, through the resistance, 13, and induction coil, 13'. The A.C. potential at 8 is rectified at the same time that it functions as a "plate potenial." A third secondary, 9' ' ', feeds a resistance, 14, and affords a current the potential of which is opposed to that of the anode. The resistances 7 and 14 are connected in series and to the metal plate on the outside of the mercury vapor tube, 11, as well as to the plate of the amplifying tube. The sound is picked up by the microphone, 1, and these are amplified by the radio tube, and these amplifiea potentials are impressed on the cathode of the mercury vapor tube. Book Review SPEECH and HEARING — By Harvey Fletcher, Ph.D. 331 pages, fully illustrated. 6x9 inches. Cloth binding. Published by D. Van Nostrand & Co., New York City. Price $3.50. ALTHOUGH this book was originally intended for the welltrained engineer in the highly techni ■ cal realm of sound, its phases are so many and its substance so widely comprehensive, that it cannot fail but be of interest to everyone who has anything to do with speech and hearing. Then, too, the very interesting style of the author makes the work more than a mere reference, more than a textbook. While sound is one of the most common of all our faculties it surely is the least understood. It was only some fifteen years ago that Bell Telephone Laboratories undertook a comprehensive study of speeeh and hearing in order to get the fundamental facts on which to base the design of all their telephone instruments. They found the field almost void of any previous investigation; in fact, they had to Jevise their own measuring instruments. Bell Telephone Laboratories is the outstanding technical research organization in the world, thus they were able to proceed with an investigation which practically made a complete science out of an almost unknown natural phenomenon. The results of these extensive researches a-e ably recorded in Speech and Hearing by the man who directed them, Dr. Harvey Fletcher. The book is divided into four sections. The first part deals with speech and, among other things, shows the complete mechanism of speaking and concisely analyzes the different speech sounds, tells how they are produced, and explains what makes them understandable. The second section deals in similar fashion with music, telling us exactly what enables us to distinguish one musical instrument from another, and one musical sound from another, together with an explanation of pitch. The third part is concerned with the mechanism of hearing and explains just how different sounds affect the ear and just how the message of a sound is transmitted to the brain. In the fourth section there is set forth at length the effects of various other sounds on the brain of the hearer. Various types of deafness are classified, and the different tests for each type are stated. It is interesting to note that a person may have normal hearing for speech and yet, for all practical purposes, may be deaf to music. Speech and Hearing is an absolute essential for the serious worker in the field of sound; but it is doubtful if, because of its highly technical style, it will have more than a limited appeal to others. — S. Wein. Local Union 306 and RCA Organize School FOLLOWING negotiations with Sam Kaplan, President of Projectionists' Local No. 306 of New York City, arrangements have been made for a special course of instruction for projectionists of the New York district to be held at the Service and Installation Department of RCA Photophone, Inc., No. 438 West 37th Street, New York City. A meeting held at the same place was attended by Vice-President C. F. Eichhorn, Secretary Frank Day and Business Agent Simon Terr of Local 306; LeRoy Cox, chief projectionist of RKO; Harry Rubin, chief projectionist of Publix Theatres, and about 150 projectionists from various New York theatres. Plan of Instruction During the meeting definite plans were made for classes, assignments, lectures and demonstrations. The first of these lectures and demonstrations was presented at that time by H. B. Braun and A. R. Schulze and was very favorably received by all present. The regular school course got under way Thursday, December 12, on which date two groups of twelve men each received personal instruction on the subject of the RCA Photophone Soundhead and were given reading matter, containing illustrations, for study in the week intervening between the first and second instruction periods. It is planned to continue these lectures and instruction periods until every projectionist in the territory covered by Local No. 306 has acquired a thorough working knowledge of Photophone equipment. RCA Photophone, Inc., feels that arrangements made will be beneficial to all persons connected with sound projection and is planning the establishment of similar schools in other cities. Scranton L. U. Elects Officers The following have been elect d officers of Local Uni.n 329, Scranton, Penn., for the year 1930 : — John Peep, President; Fred Hopf, Vice-President; Glen Ornstein, Fin. Secretary; Joseph Namitka, Rec. and Corr. Secretary; George Miles, Treasure..; S-.muel Kessler, Business Agent. Trustees for the coming year are Harry Granville, Joseph Smith, and Harry Litts.