New Light

In Western Union's Long Island laboratory, a new kind of lamp was shining last week. It might not be the biggest, the brightest or the most economical, but designers and users of optical instruments were excited about it. Reason: its light came from a speck of molten metal only three one-thousandths of an inch in diameter.

Ordinary lamps emit light from a considerable area, usually a glowing coil of tungsten wire. This makes shadows fuzzy, causes all sorts of trouble in optical instruments. Scientists have long yearned for a convenient, cool "point source" of light. Now, according to Western Union, they had it.

Western Union calls its lamp a "concentrated arc." Inside a small glass bulb filled with argon gas are two electrodes. On one is a tiny speck of zirconium oxide. When the current flows, this turns to molten zirconium metal, glows ten times as brightly for its area as the brightest tungsten filament.

The new lamp did some startling tricks. The shadows it cast across a 40-ft. room had sharp, un-fuzzed edges. When the smallest model using only two watts of current was held behind a color film the size of a postage stamp, it projected a clear, sharp "shadow picture" as big as a telephone book. When used in an ordinary photographic enlarger, it made monstrous enlargements of startling clarity.

No one claimed that the "point source" light would soon replace the present bulbs and fluorescent tubes (it cannot be used on ordinary house current). But its inventors believe that it will improve all sorts of optical instruments, from high-powered microscopes to motion-picture projectors.

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