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...