The Bioscope (Jul-Sep 1931)

September 9, 1931 THE BIOSCOPE Technical News and Notes New Way of Sealing Contracts An alert reader draws my attention to an amusing misprint which occurred in last week’s issue. In describing the new ingenious vacuum switch, the writer of the article was apparently guilty of saying that this switch “ caused the mechanical actuation of contracts sealed in vacuum.” Needless to say, the actuation of “ contacts ” was intended. The " mechanical actuation of contracts sealed in vacuum” reads as though one of the functions of the corner publichouse had been unexpectedly superseded. Metal-clad Film There have been various methods proposed in recent years for increasing the life of cinematograph films by reinforcing their resistance to wear and tear. This has usually taken the form of solutions or waxy dressings. The latest consists of an armour-plating. A thin copper band is so attached to the film that it cannot loosen, and this copper band protects the perforations, although it does not enter the field of photography. The whole arrangement is guaranteed to prevent tearing or breaks due to worn perforations, and it is said that the British rights have already been sold for a large sum of money. Clever One-lamp Sign The other day when I was at the Holophane Works, Mr. Thompson, the managing director, showed me a new form of a frontof-the-house sign the company is about to introduce, which ought to have a tremendous success. By an ingenious system of cleverly calculated reflection angles a single 60-watt lamp is made to give a brilliant and even illumination to a 12-inch letter. The letters themselves are made in a novel way in raised ribbed glass so that the effect is almost that of a Neon lamp. In another type the letter is masked on its front face by an opaque substance so that only the edge of the raised letter, in this instance of green glass, was visible. It was difficult to believe that one small lamp should achieve so startling and pleasing an effect. There is no doubt whatever that a great deal of light at present used on the exterior illumination of cinemas is unnecessary and the tendency from now on will be to secure the equivalent illuminating effect with a reduction in the number of lamps employed. To be able to illuminate the whole of one’s house sign by a dozen 60-watt lamps is something of an achievement. I do not know whether I am a little premature in suggesting that readers apply to the Holophane Company for particulars of these new lamps, but those who are contemplating the erection of a new indoor or outdoor sign should certainly make a note of this new Holophane line which has not so far, I believe, been given a trade name. If for no other reason than this, the new demonstration room of the Holophane Company at Victoria is well worth a visit. Incidentally, Mr. Thompson informed me that, partly due to the Illuminating Congress, the company have been inundated with orders in some departments far beyond their capacity — an unusual and welcome thing to hear in any branch of trade nowadays. Testing Sound in Desert A party of Western Electric recording experts recently donned desert explorers’ garb, and set out from Los Angeles for the Mojave. Their quest did not concern gold, but the testing of a portable recording channel and directional microphone under actual production conditions. The apparatus, including the directional baffle, was transported in a Western Electric newsreel truck and a Ford truck. The portable channel was that which had been designed for the Caddo Company. This was mounted on the newsreel truck. Although at times high winds are experienced in this area, the morning the tests were made was so quiet that footsteps 100 ft. from the microphone were clearly recorded ! The tests consisted of making recordings of speech with the ordinary condenser type microphone, and a similar microphone in the directional baffle. A Room with a Warm Skin It is well-known that in winter the cold walls of a room absorb the heat radiated from the human body. If the walls are, themselves, at a temperature approximating to that of the human body this loss is reduced. The Westinghouse Research Laboratories are, at the present moment, experimenting with a small room that has what may be called a warm skin. The walls and ceiling of this room — -like the skin of the human body — radiate a mild temperature that is barely warm to the touch. This heat is produced by electric heating elements which are contained in the panels or sections which make up the walls and ceiling. The entire surface may be heated at once or the heat may be switched on in one or more sections where it will do most good The engineers are using this room to determine the exact combination of wall temperature, air temperature, air movement and humidity that will produce the most comfortable living conditions. These experiments may well mark the beginning of an era in which the walls of our private and public buildings are, themselves, mildly heated without any other external heating devices. Wonderful Time Switch The General Electric Company has just devised a new Time Switch which will find plenty of users in the cinema world and which seems to have almost human powers of observation and control. This switch will turn lights on and off at dusk and at dawn, or at any predetermined time before or after sunrise and sunset. It will make due allowances for geographical latitude and longitude and for the season of the year. It can be made to take holidays, omitting its operations on any desired days of the week. It performs such operations as starting motors in the morning, starting and stopping them throughout the day, according to workers’ schedules, and turning them off at the end end of the day. It will turn on heating plants so that buildings, theatres, etc., will be adequately heated and ventilated by any predetermined time. To duplicate the possibilities of this new time switch a man would need an almanac, a knowledge of latitude and longitude, a precise watch, a degreeTof punctuality far above the average and the ability to be awake and alert at all hours of the day and night. The switch can do two or more things at once. It can turn off£one set of lights and turn on another at the same