Lamp

a cup-like receptacle in which oil is fed to a flame by means of a wick. The ancestry of the lamp is shown by the fact that the word lamp is from the Greek lampas, meaning a torch. In Greek mythology, Demeter went forth with a torch seeking her daughter. Psyche lets fall a drop of hot oil on Cupid and wakes him. The relative age of the two myths is easily inferred. The earlier lamps were plain, shallow, earthenware cups with a projection at one side for the wick and another on the opposite side to serve for a handle. The traditional "lamp of learning," figured on diplomas and college coats-of-arms, is of this sort. Similar lamps are still used by the peasantry of the Apennines. The lamp played an important part in the religious festivals of the Greeks and Romans. Bronze lamps came into favor with the Greeks. The Erechtheum on the Acropolis had a gold lamp of exceptional beauty designed by no less an artist than the sculptor, Callimachus. When trimmed and filled it burned for a whole year.

From time immemorial cotton has been used for wicks, although any fibrous wick with capillary action will answer. The English peasant used a rush. Of all forms, the round, solid wick, formed like a cord or rope, is the poorest. Air reaches the outside only. The oil drawn up by the center of the wick has little chance at all and burns with a smoky flame, producing lampblack. A flat wick is better. The entire flame is supplied with air, but the light thrown out is not uniform in all directions. Of the improvements in wick and burners that devised by Argand of Paris about 1780 is the most notable. The Argand burner consists essentially of two hollow brass cylinders or tubes, one within the other. The wick, also in the form of a hollow cylinder, passes up between these two. The wick presents a circular exterior, thus having an advantage over the flat wick in that it throws light in all directions. The inner tube feeds air to the inner surface of the wick; the supply of air to the outer surface is increased by a draft-creating chimney. The next notable improvement in the lamp is the so-called students' lamp. An elevated reservoir causes the supply of oil to flow more freely and uniformly than is the case when the feed depends on capillarity.

The present generation is apt to think of kerosene oil only. People who are still in middle age can remember the introduction of this oil. Prior to the Civil War, whale oil, sperm oil, fish oil, and lard oil were used chiefly for lighting. Vegetable oils serve quite as well. The oil with which the wise virgins of the New Testament filled their lamps was doubtless olive oil. Cocoanut oil is used in tropical countries. Poppy oil, sesamum oil, and ground nut oil are used locally. Without doubt the oil of various North American nuts could be burned in lamps. In populous districts gas and electricity have superseded oil to a large extent, but the lamp is still one of the world's necessities.

See Davy; Electricity; Gas; Spermaceti; Candle; Light