The idea of burning oil to produce artificial light probably dates backs hundreds of thousands of years, to when primitive peoples cooked meat by open fire and must have noticed the light given off by fat dripping onto flames. By 70,000 B.C., the Stone Age cave-dwellers of western Europe had invented the first oil lamps, which were made from hollowed-out stones that held a piece of moss or other spongy plant soaked with oil or grease. These lamps were likely used to illuminate caves and allow primitive artists to decorate the walls with paintings. Around 2000 B.C., Iberian (Stone Age English) flint miners used similar lamps made from lumps of chalk to illuminate underground mines. Today, Eskimos still burn walrus and seal oil in lamps comparable to those of the Stone Age. Some time before 1000 B.C., people learned to make wicks from dried rushes or...