Motion Picture Herald (Jul-Aug 1936)

of the company, has been at all times glad to co-operate. (It was "Mac" who evolved, invented or what-have-you, the slogan, "Better Projection Pays," which was very effective in the cause of improved projection. ) I have had invaluable aid from many companies. John Hertner, president of the Hertner Electric Company, is another who has given unstintingly of his time to help. Larry Porter and others of General Electric, the Westinghouse engineers, Erpi, RCA and Bell Laboratory engineers have responded whenever called upon, which has been many times. The National Carbon Company engineering department has also been most helpful and kindly. And when I come to projectionists, I hardly knoAv where to begin or where to stop. John Griffiths of Ansonia, Conn., surely did yeoman service in aiding in the field of projection optics. Chauncey Greene of Minneapolis is another who has been of great help, and that young-old war horse, George Edwards, whom you all know, did likewise. Lester Isaacs, director of projection for Loew's, and M. D. O'Brien, his very able assistant, must not be overlooked, while Harry Rubin and Jessie Hopkins, who hold corresponding positions with Paramount, are likewise to be gratefully remembered. Then there are Harry T. Dobson and Charles Dentlebeck of Toronto; G. W. Bennewitz of Sioux Falls, S. Dak. ; the late Arthur Gray of Boston, and many others. They were not merely of help to me, but they contributed generously to the cause of better projection that I was working in. Oh yes, I almost failed to mention my old friend, W. G. Woods, of San Francisco, who years ago, when help was needed badly) gave of his time and energy liberally. "Pop" Woods was one of the very real pioneer projectionists. And many others — too many to be read here. Don't want any of 'em to think I'm one of those take-and-forget guys. Hence this little reminder of my gratitude. REMARKABLE SOUND QUALITY the other day Lester Isaac, Director of Projection for Loew Theatres, invited friend daughter and her dad to visit the Capitol theatre in New York and witness Metro-Goldwyn-Mayer's "San Francisco." It was one of those parboiling days we "enjoyed" a short while back, and we were not keen, but Mr. Isaac assured us we would see and listen to some remarkable effects. So, knowing the thing must indeed be quite out of the ordinary to cause Mr. Isaac thus to enthuse, we went — and take it from us, we are glad we did, for while it is not the province of my department to describe shows, I can and should compliment Mr. Isaac and his able assistants, as well as the projectionists of the Capitol theatre. The visual effect was such that we offer no criticism thereupon; the sound, particularly in earthquake scenes, was unusually realistic and effective. The sound we heard at the Capitol cannot as yet be duplicated in all theatres since in the Capitol there has just been installed new, highly improved sound equipment. NEW SUPREX ARC PROJECTION LAMP A new model projection lamp designed for use of suprex carbons, has been developed by the Morelite Company, Inc., of New York. It has been given the trade-name of Morelite MonArc. The lamphouse is of sheet steel and aluminum. On either side is a large door (both are open in the illustration to show the interior mechanism) held normally in closed position by spring action. When raised to open position a lamp inside is automatically lighted and the door is held in open position until pulled shut, which action automatically extinguishes the lamp. The carbon jaws are of heat-resisting composition metal ; the means for clamping the carbon in place are very simple and effective. The front or tip end of each carbon is supported by a V-shape guider of heat-resisting metal, the one supporting positive adjustable vertically; the other both vertically and horizontally. The 14-inch elliptical reflecting mirror may be moved backward or forward horizontally, or tilted as may be required. Its backing is of imitation stone. Immediately in front of the reflector is a metal dowser designed to protect the mirror surface from pitting by incandescent carbon or copper particles when the arc is struck. This dowser is so connected with the regular lamphouse-cone dowser that one handle operates both simultaneously. A movement of this handle opens the cone dowser and raises the one in front of the mirror up out of the way. An opposite movement of the handle closes both. Directly beneath the arc, on the lamphouse floor, is a metal tray. The arc control is ingeniously planned. Near the lamphouse floor, immediately under the positive carbon, are two coarsethread rods about 0.75 of an inch in diameter, called twin feed screws. They are separated from each other a short distance and are approximately 10 inches long. The twin feed screw furthest from the projectionist carries a spur gear with worm connected, through a ratchet device, to the motor. It therefore rotates whenever the motor is in operation. The second of the twin feed screws is connected, through proper gearing, with a hand-wheel outside the lamphouse, which latter may be turned fast or slowly without interference with operation of the first feed-screw. Each movement of either twin feed screw moves a freely revolving small gear that is in mesh with both feed screws, in such manner that any movement of either feed screw carries this small gear forward or back, whether the movement be caused by the motor or by the before described hand-wheel. The small gear is attached to the carbon arm base, hence as it is moved backward or forward it carries the carbon arm and carbon along with it. At the rear of the lamphouse is a space enclosed by an aluminum metal door which, when open, gives access to all parts. There are, of course, all necessary control knobs, handles, etc., conveniently located. Speed of both carbons may be mechanically adjusted by so-called speed regulators, in such manner that either may be made to feed forward faster or more slowly while the arc is in operation, without in any way affecting the speed of the arc control motor. As extra equipment, a "Mir-O-Guard" is supplied, consisting of a sheet of glass about 3^ -inch thick and bent to fit the face of the mirror, shielding it from pitting or other damage. There is a double screen, visible from either side of the projector, upon which an image of the arc is focused. An automatic cut-off is supplied to prevent the burning of carbons too short THE WHY OF LIGHT REFRACTION our old friend, John Griffiths, projectionist and author of "Dynamic Ether," writes, "Dear Frank: May I offer comments upon the simplified explanation of light refraction contained in June 27th issue of Better Theatres, in which John Randall writes, 'My puzzle now is that I cannot quite understand why the direction of light is altered when it enters glass or passes out of same. Have read many explanations, but none seem to make the matter clear.' May I suggest that the matter still remains unanswered, despite the simple explanation offered. "A column of soldiers on march could cross a strip of deep sand, placed diagonal to the line of march, without in any degree altering the direction of the line of march, provided it be not required that their front line be at right angles to the line of march. The actual cause of the change of direction is due to the fact that light can only travel in a direction normal to the wave front represented by the front row of the column of soldiers. Were the soldiers in single file, there would be no alteration in their direction. There would be no influence to change direction, hence we cannot assume the change in velocity and incident angle to .be wholly responsible for the alteration in direction. "The only reasonable conclusion that 36 Better Theatres