HOW NEW TELEVISION PROCESS WORKSDescribed as one of the greatest triumphs in the history of communication methods, the television process of the American Telephone and Telegraph Company is the product of many minds working together in the Bell Laboratories in New York under the direction of Dr. Herbert E. Ives. |
THE TELEVISION TRANSMITTER. R.C. Mathes of the Bell Laboratories technical staff is seated in front of the box containing three photoelectric cells. The moving spot of light shines through a hole in the box. The motor which runs the revolving disk and part of the disk itself can be seen in the opened cabinet.. |
Despite the elaborateness of the apparatus, television depends essentially upon the fact that a film of potassium metal in a vacuum tube can be made to give a small electric current when light shines on it. This is the photoelectric cell. The method of its use in the new process is quite different from previous attempts to attain the same result.
In other methods, the subject, whose visage is to be transmitted, is flooded with brilliant light and a lens picks up the illumination and focuses it on a small photoelectric cell. In the new method, by the idea of Dr. Frank Gray, the subject is illuminated with a tiny moving spot of light, which is picked up by a battery of large photoelectric cells -- the largest yet made. The result is the must successful transmission of the actual view of the human face that has yet been achieved.
As seen on the small receiving screen, the scene looks like a halftone two inches high, printed in the pink sheet edition of a daily paper, except it has come to life.
Cathode rays, which aroused great expectations a few months ago when Dr. W.D. Coolidge of the General Electric Company exhibited a more powerful machine for producing them, are already fulfilling their hopes. At a meeting of the American Chemical Society, their effect in speeding up the drying of paint was discussed by Prof. J.S. Long of the chemistry department of Lehigh University.
In collaboration with a group of his associates, Professor Long exposed a number of glass plates coated with linseed oil, perilla oil, and China wood oil, all standard paint materials, to the action of rays from the Coolidge tube, and also exposed similar samples to blasts of warm air and to beams of ultraviolet rays to obtain comparisons of the speed of drying and hardening produced by these methods.
"The time required for the oil without dryers to become dry to the touch or to dry hard was found to decrease in a regular manner as the time of exposure to cathode rays increased up to 10 minutes," Prof. Long stated.
For more information, see Crystals Glow with "Cold Light" Under Cathode Rays
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