International projectionist (Nov-Dec 1933)

32 INTERNATIONAL PROJECTIONIST November 1933 UTILIZING THE RADIO MAN IN EMERGENCIES (Continued from page 27) radio man in the matter of spare parts he can furnish if needed, there is every reason why he should be invited to look at the theatre's sound equipment. If he has any reasonable hesitation about lending his valuable test meters for work on that equipment — and no doubt he will — there is no reason why he should not be invited to assist in the work of inspection and emergency repair, and use his precious meters himself. In some cases a small weekly or monthly payment to the radio man may be necessary, but in most instances, perhaps, the opportunity to do "extra" work for the theatre with his loud speakers and amplifiers (at the usual charge ), coupled with the inside opportunity to sell the theatre such parts as it has not definitely arranged to buy elsewhere, will find the radio man more than pleased to donate his personal services. But however the details may vary, in general it should be possible to obtain the necessary spare parts of the radio man, his valuable meters, and his personal services in assistance to the projectionist, for no other return than preference in business the theatre has to give to someone in any case. There is still another way in which the theatre can pay the radio man without any cost to itself, and that is by offering him its lobby for the display of his radio sets and other products. Most of these methods of inexpensive compensation do, however, from the point of view of the projectionist, possess the disadvantage of injecting the radio man into the picture as the direct auxiliary of the manager, rather than, as should be the case, as an assistant to the projectionist, under and within the limits of his responsibility. Therefore, if any such arrangements are to be made the projectionist must take the initiative in making them, and not wait until the radio man or the manager do it for him. GREATER EFFICIENCY WITH PRESENT D. C. ARCS (Continued from page 23) the angle of deflection will be the angle of the equivalent voltage and therefore the force of the electronic bombardment will depend upon: permeability X intensity X current The outer shell of a carbon is more or less of a support, and while it does volatilize as a result of the stray electronic impacts and surface radiation, it is practically the conducting path for the lines of force, with the surface area being in proportion to the number of lines of force necessary to carry the current and voltage. Distributing the Burden As the carbon shells are the conductors, and the electronic emission is the bombarding element that drives the chemicalized core to a white incandescence, the heat radiating and volatilization factors of the carbon shell also bear a certain portion of the burden. In Important New Books In The Field THEORY OF THERMIONIC VACUUM TUBES FUNDAMENTALS— AMPLIFIERSDETECTORS BY E. LEON CHAFFEE Professor of Physics, Harvard University A thorough and authoritative treatment of vacuum tube fundamentals containing much new and hitherto unpublished material. 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