Firefly
a light-giving, usually nocturnal beetle, sometimes, but not happily, called a lightning bug. The glowworm of Europe is also a beetle, closely related to the firefly, but it is wingless and crawls like a worm. The firefly family is a large one including many species. Those of the West Indies are an inch in length and give out a light by which small print may be read. A few put under a tumbler are sufficient, it is said, to light a room. Our common firefly is a familiar torch bearer. Its fitful gleams show that summer is at hand. As the warm, dewy evenings come on, there are few scenes more to be admired than a meadow with thousands of these little meteors in full play. On catching one of them-not the easiest thing to do-it appears to be a slender, soft beetle with flat wing covers which it raises fitfully, emitting a beautiful glow of light from the under side of its abdomen. Scientists have wondered not a little how so small an animal can emit so much light. A bit of burning tallow or a drop of oil, even with the utmost economy, is soon consumed.
No way of converting fuel, heat, chemical action, or electricity into light has been devised or is conceivable without consumption of the light-producing material. Yet nature produces a myriad of soft, delightful evening lamps that glow and shine for hours without apparent loss of weight. Without doubt, however, the firefly derives its light from the food it eats. Beyond the fact that the light or phosphorescence is due to action, it is little understood. See Phosphorus
"We have made a new profession, that of illuminating engineering, but we are still very far from the perfect artificial light," remarked a well-known inventor.
"Is there such a thing as a perfect source of artificial light?" asked one of his auditors.
"Oh, yes, we already know of such a light. Almost everybody has seen this light, but all the wise heads in the world cannot read this simple secret which Nature has seen fit to bestow upon her most lowly forms of animal life. Behind you sits a darkened cabinet; inside of it is a little box. Shake that box a bit and you will see the only perfect source of light known to man."
With eager faces the visitors crowded about the cabinet. Then with the look of disappointment one turned towards the inventor with the remark: "Why, there's nothing but glow-worms and fire-flies in that box!"
"Nothing but glow-worms and fire-flies," remarked the scientist, "and yet each one of those little creatures carries around a secret worth millions and millions of dollars. If I could discover that secret to-day, inside of a year I could make the fortunes made out of oil look like the widow's mite. For, do you know, each one of those fire-flies and glow-worms carries a tiny light which they turn on and off at will? This little light gives very little or no heat, whereas the best incandescent electric lamps we can make waste more than 90 per cent of the electrical energy in useless heat for what little light they give. Take that sixteen-candlepower lamp above you, for instance; it consumes fifty watts of electricity to produce sixteen candlepower of light. Only two watts of this go to make the light and forty-eight watts are wasted in heat. If I could reverse those conditions I could get twenty-four times as much light, or 384 candlepower, from the same amount of current. Fire-flies and glowworms know the secret of light without heat,-man does not. But some day we will read this puzzle, as we have read so many before, and the nights will be as day. In the depths of the ocean even the penetrating light from the sun is barred, yet there is light, and electric light, too. Almost every one of those deep-sea creatures carries a tiny light similar to that of the fire-fly,--a light that can be turned on or off at will. We assume that the 'electricity' for this light is produced by nervous energy; beyond this we really know nothing."-Donald Cameron Shafer, in The Technical World.