By The Light Of The Firefly

Not so long ago a lamp that could hear was demonstrated at the Newark, N. J., airport. This lamp's ear was attuned to pick up or catch the note of a certain siren. That particular siren was a part of the equipment of an airplane that came soaring over the airport. The aviator sounded the note, the ear heard, and hearing it operated a switch that caused the landing field to be flooded with light, enabling the airman to land safely. It is a valuable contribution to aviation.

This "lamp" was really a vacuum tube, a close relative of the radio tube, equipped, through the wizardry of science, with a sensitive ear. There are today many other marvelous lamps with which we are far better acquainted. They range from the tiny "grain of wheat lamp" that dentists and surgeons delight in using when making their explorations in the internal regions of the human body, to the brilliant radio beams whose rays are visible for miles from the point of emanation. When we think of these lights, compared with which even Aladdin's wonderful lamp must fade into insignificance, it is almost impossible to realize what crude methods of lighting have been, and even now are, in use.

Nearly every one knows what an important role the stormy petrel, the now extinct auk and the candlefish have played in furnishing man with light. The methods by which they were converted into torches, and lamps are familiar to all. But there is one natural source of illumination that has been used in effective and ingenious ways, about which comparatively little has been written. That is the firefly. In an early account of tropical America an historian speaks of a great beetle "somewhat smaller than a sparrow, having two stars close by its eyes and two more under its wings." This large beetle's lighting plant furnished such good light that the natives were able to spin, weave, write and paint by it. The Spaniards, when they wished to hunt at night, fastened beetles to their thumbs and big toes. Used in this way the insects served the double purpose of making light and luring little rabbits that were attracted by die light.

Fireflies that were not large enough to be tied to thumbs or great toes have been used extensively in a great many countries. Naturally enough, because they were used in such numbers, it was necessary to provide means to confine them. Novel methods for accomplishing this were devised. In the West Indies they use a lantern, a sort of three-story tenement, made with gratings of small rods. A somewhat simpler house of detention, prison, or lantern, as the case may be, is a common gourd with a number of perforations and a crude door.