LAMPS are contrivances in which to burn any light-giving material, and so make use of its illuminating power. The most primitive lamps were probably the skulls of ani mals, in which fat was burned; and certain sea-shells formed admirable lamps for those to whom they were attainable. To this day, there may occasionally be seen suspended in the cottages of Zetland, shells of the "roaring buckle" (fusus antiquus: see Fusus), which form, perhaps, the most ancient kind of lamp in existence.
When pottery and metal began to be used, the principle of these natural lamps was for a long time retained, as seen in ancient Egyptian, Greek, and Roman lamps, and in the stone cups and boxes of northern nations. The invention of lamps has been attri buted to the Egyptians, but it is far more probable they received it from the older civili zation of India. Herodotus (ii. c. 62) reminds us of the Chinese feast • of lanterns, by speaking of the feast of lamps at Sets, in Egypt. Such lamps were called lychna by the Greeks, and lucernce'by the Romans, and various modifications of the form are frequently found in the ruins of Greek and Roman cities; very considerable numbers have been obtained from the excavations of Tarsus and of Pompeii and Herculaneum. The prin ciple in all is the same. At first, these lucerne were made of unglazed pottery, and only with one wick-hole; but better material and more elaborate forms were introduced. and their light-giving power was increased by their being made to hold several wicks, front two to twelve. The wick used in this lamp was generally mode of flax-tow, sometimes, however, of rashes and other vegetable fibers.
Amongst the northern nations of antiquity, lamps were in use, but the difference of climate necessitated a different kind of lamp. The limpid oils of the present day were unknown to our Celtic and Saxon forefathers; besides, the cold winters would have solidified them, and they would not have been drawn up by the wick, if arranged as in the old Roman and Greek lacermt. The solid fat of various animals was their chief illu minating material, except on the sea-coast, where seal and whale oil occasionally helped them. Small open stone pots, afterwards exchanged for metal, were used, and being partly filled with grease, a wick was thrust down through the middle, and being lighted, consumed the fat as it melted. Stone cups of this kind arc occasionally dug up in Scot
land and elsewhere: in principle, they are the same as the padelle, used in Italian illu minations, and the old grease-pots, which formed the foot-lights of our theaters not many years since, and which may still occasionally be seen in the traveling-shows at country fairs. The Esquimaux form square boxes of soap-stone, and use them in the same way.
No great improvement took place in the construction of lamps until the beginning of the present century. Taste had been shown in the designs, but the principle remained the same: a wick sucking up oil from the reservoir of the lamp to supply itself during combustion,.and nothing more, if we except the improvement effected by the invention of M. Argand in 1784. See ARGAND. In 180331. Cared, another Frenchman, made an excellent improvement on the lamp by applying clock-work, which acts by raising the oil up tubes in connection with the wick, so that the latter is kept continually soaked. If properly managed, this is perhaps the best of all oil-lamps, as it will keep up a well sustained and brilliant light for seven or eight hours, and the light rather increases•than otherwise as the lamp burns and becomes warmer, thereby rendering the oil more limpid. But the Cared lamp has two disadvantages: it is expensive, and is easily disarranged, therefore it has never become common.
The French moderator lamp is much simpler, and appears to overcome the difficul ties of the case. The body of this lamp consists of a cylinder or barrel, the lower part of which contains the store of oil. On the top of the oil rests a piston, is con stantly pressed down by a tpiral spring, situated between it and the top of the barrel. Through the piston is inserted a small tube, which passes up to the burner at the top; and the pressure of the spring on the piston causes a constiint stream of oil to rise up through this tube and feed the wick. What is not consumed flows over the burner, and back into the barrel above the piston. It is above the piston also that fresh oil is intro duced. When the piston has reached bottom, it is wound up again by a rack and pinion, and a vacuum being thus formed, the oil above iv is forced to the under side through a valve kind of contrivance round its edge.