Science: Lamp Trick

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The bland orange-yellow of sodium-vapor lamps now lights hundreds of miles of U. S. highway. Until recently it has been a ticklish and costly job to get the sodium into the highly evacuated lamps without contamination. Last week General Electric Co.'s laboratories at Schenectady announced a clever new way of filling the bulbs. The sodium is packaged in tiny, frail glass capsules, a capsule placed inside each lamp, the lamp pumped out and sealed. Then short radio waves are turned on the capsule. It heats up, explodes. The sodium is thus freed inside the lamp and the broken capsule is reduced to a harmless pinch of powder.