PLAYING PING PONG TO TEST NEW LIGHTING
CD 1964099 E&MP27.080
MAR 22 1934
From a delightful indoor sport, ping pong one evening was elevated or degraded -- purely a matter of viewpoint, of course -- to a practical engineering demonstration of the latest kind of electrical illumination. Before a recent large gathering of members of the New England Section of the Illuminating Engineering Society, O.H. Biggs and W.P. Lowell, Jr., both of the lamp engineering department of the Hygrade Sylvania Corporation, arranged for several ping pong matches under a huge canopy containing the usual tungsten filament lamps and the latest sodium vapor lamps, either set being switched on at will, so that the characteristics of both kinds of illumination might be studied with regard to fast-motion vision.
These enterprising engineers set out to find, by practical demonstration, whether the new sodium vapor lamp, which so far has been tried out only for highway lighting, would help or hinder sight in the fast action called for by a game like ping pong.
They wanted to determine whether the flicker of sodium vapor lamps - and there are 120 flickers per second with the ordinary alternating current circuit - would have an appreciable effect on the action. And they further tried to determine whether the absence of all colors, except yellow, would make any difference to the players, for under these lamps everything appears yellow, gray or black.
Now, while a single experiment like this does not furnish sufficient evidence for engineers to formulate any opinion, it did add something to their knowledge of how human beings react to two different kinds of light.
The ping pong games did indicate some stroboscopic effect; that is, the ball and paddles did intermittently flash before the eyes. To. some it seemed more noticeable than to others, and opinion was very much divided as to whether it is an asset, drawback, or immaterial. Two sets of sodium lamps operating on different phases served to reduce materially the stroboscopic effect.
But the color of the light, at least to those who tried playing the game, made no apparent difference. For while, as one expressed it, you see better but not so much under the deep yellow, almost amber light of sodium vapor, the contrast was not marked enough to reveal any departure from normal in the eye activity or see-ability of the players. Much more experimenting will have to be done before these Hygrade Sylvania engineers will be able to give any positive fact about the two kinds of lighting.
The present interest in the sodium vapor lamp is due to the enormous gain in luminosity with a given current consumption or wattage rating. The new lamp produces two and half times as much light as the usual tungsten filament lamp of corresponding wattage. This enormous saving in current consumption is attracting the attention of illuminating engineers particularly with highway lighting in mind.
,br>For the illumination of the ping pong table installed in the Hygrade lamp plant recreation hall, a huge canopy containing both Sodium vapor and tungsten filament lamps, was suspended from the ceiling. To avoid glare and secure ideal light diffusion, a totally indirect lighting system was employed, the lamps being concealed in a recess around the inside rim of the canopy so that their light could reach the table below only by being reflected by the inside white surface of the canopy. Twelve sodium vapor lamps of special design, and twelve tungsten filament lamps of approximately double wattage to give equal lumen output, were mounted in the canopy. These lamps were provided with switches and light shields, so that either incandescent filament lighting or sodium vapor lighting from hot lamps could be obtained.
Original Caption by Science Service
©Hygrade Sylvania Corporation