International projectionist (Jan-Dec 1935)

April 1935 INTERNATIONAL PROJECTIONIST 25 buy new equipment. Subscribing to Mr. Hoffman's views anent the A. C. arc and, secondly, on conversion jobs, it is apparent that this point of view carried to its logical conclusion would ultimately mean the vanishing of any semblance of projection standards — whether the consideration be lamps, lenses, screens, or any other unit of equipment. Thus the cost picture. Considering the technical side of the question, it is apparent that this discussion is utterly ridiculous. Mr. Hoffman makes no attempt to contest the evident superiority of the D. C. Suprex arc as a light source; in fact, freely admits it. The A. C. arc will always appear to this writer to be a technical bum, a projection outcast, and this sentiment applies also to conversion jobs. ELECTRIC SHOCK C. J. McGlogan Reprinted by permission of ELECTRICAL WORKERS' JOURNAL Effects of electric shock on human beings and animals have been studied exhaustively during recent years by Dr. W. B. Kouwenhoven, assistant dean, School of Engineering, Johns Hopkins University. Some of his findings constitute information which should be possessed by all who work with electrical circuits. For example, he has found that low-voltage alternating current is more dangerous than low-voltage direct current; that high-voltage direct current is more dangerous than high-voltage alternating current; that high-frequency circuits are relatively harmless, and that with sufficiently good contact 60 volts can kill. With a given condition of contact resistance, he has found that 10 volts caused a flow through several persons of one niilliampere of current, 20 volts produced 2.5 milliamperes ; with 30 volts it was 12, and with 40 it was 20 milliamperes, under which condition only one of the recipients could release the electrodes. The path of the current he has found to be important, being most dangerous if it includes the heart. It has been found that 110 milliamperes, flowing from the hands to the feet, can kill. The time factor is important, however, one case being on record in which the victim carried 28 amperes for a brief period without fatality. The several effects of electric shock can be divided into four classifications as follows: 1, the victim is burned or cooked; 2, brain cells are destroyed; 3, heart action is stopped; 4, breathing is stopped. The first two conditions may not be corrected by emergency treatment, but the pain of an electric burn can be relieved as that of any other burn. A heart that is stopped will often start again if artificial respiration is resorted to. Sometimes electric shock will cause fib RIDE THE CREST OF POPULARITY WITH RC0 VICTOR PHOTOPHONE THAT GIVES GREATEST SOUND SATISFACTION and OFFERS YOU: • A Sound Box-Office Attraction • Complete Ownership • A Self-Liquidating Investment • RCA Super-Service PHOTOPHONE DIVISION RCA Manufacturing Co., Inc. Camden, N. J. A Radio Corporation of America Subsidiary rilation or fluttering of the heart, under which condition insufficient blood is pumped and the heart continues to flutter until the patient dies. This can be corrected by a saline treatment or by the administration of a stronger shock which stops the heart, after which it will start again. These treatments can only be given by a specially trained person, but fortunately, the conditions which require them are not the usual results of electric shock. Most Common Effect Probably the most common effect of electric shock is a blocking of the nervous system which causes the lungs to cease functioning because they receive no message from the brain. It is for this reason that artificial respiration is so effective in reviving victims of electric shock. The Schafer prone pressure method of resuscitation is offered by Dr. Kouwenhoven as the most effective. It may be supplemented by an inhalator which adds oxygen to the air as the patient is caused to inhale; he does not look upon the pulmotor with favor, since it may cause bleeding. The vital requirement is to start artificial respiration immediately and continue it without cessation. A trained emergency squad will change or relieve operators or wrap the victim in a blanket without depriving him of a single breath. They do not stop be