Every-day Science: Volume 6. The Conquest of Nature

by Henry Smith Williams; Edward Huntington Williams

It was this form of lamp, practically unaltered except occasionally in design, that remained in common use during the Middle Ages; and when, at the close of the twelfth century, the "tallow candle" was invented, that now despised device must have been almost as revolutionary in its effect as the incandescent burner and the electric bulb were destined to be in a more recent generation. It burned with dazzling brilliancy in comparison with the oil lamp; it gave off no smoke and little smell; it needed no care, and it occupied little space. Then for the first time in the history of the world reasonably good house illumination became possible. Several additional centuries elapsed, however, before the idea was developed of placing a candle in a covered glass-sided receptacle, to form a lantern or a street lamp.

For generations the candle held supreme place, though its cost made it something of a luxury; doubly so if wax was substituted for tallow in its composition. But toward the close of the eighteenth century, when the action of combustion had begun to be better understood, attempts were made to improve the wicks and burners of oil lamps. In 1783, an inventor named Leger, of Paris, produced a burner using a broad, flat, ribbonlike wick in which practically every part of the oil supply was brought into contact with the air, producing, therefore, a steady flame relatively free from smoke. The flame, while broad, was extremely thin, and its light was consequently radiated very unevenly. Portions of a room lying in the direction of the long axis of the flame were but poorly lighted. To overcome this difficulty, a curved form of burner was adopted; and this led eventually to the invention of the circular Argand burner, the prototype of the best modern lamp-burners.

TALLOW CANDLE AND PERFECTED OIL LAMP

Stated in scientific terms, the problem of the ideal lamp-wick resolves itself into a question of how to supply oxygen to every portion of the flame in sufficient quantities to bring all the carbon particles to a temperature at which they are luminous. It occurred to Argand that this could be done by giving the wick a circular form like a cylindrical tube, giving the air free access to the centre of the tube as well as to its outer surface. In his lamp the reservoir of oil was placed at a little distance from, and slightly above, the tube holding the burner, connected with it by a small tube much as the tank of the modern "student lamp" connects with the burner. In this manner a fairly good lamp was produced,—a decided improvement over any made heretofore,—and when, in 1765, Quinquet added a glass chimney to this lamp a new epoch of artificial lighting was inaugurated. "This date is of as much importance in artificial lighting as is 1789 in politics," says one writer. "Between the ancient lamps and the lamps of Quinquet there is as much difference as between the chimney-place of our parlors and the fireplaces of our original Aryan ancestors, formed by a hole dug in the ground in the centre of their cabins."

A little later Carcel still further improved the Quinquet lamp by adapting a clock movement that forced the oil to rise to the wick, so that it was no longer necessary to have the burner and the reservoir separated by a tube. This was still further improved upon by substituting a spring for the clockwork, the result being a lamp of great simplicity, yet one which gave such results that it replaced the candle as a unit for measuring the illuminating power of different sources of light.

These various burners should not be confused with the modern burners of the ordinary kerosene lamps. Mineral oils had not as yet come into use for illuminating purposes, except as torches or in simple lamps like those of the Romans, as refining processes had not been perfected, and the smoke and odors from crude petroleum were absolutely intolerable in closed rooms.

Many other substances were tried in place of the heavy oils, such as the volatile hydrocarbons and alcohols, but with no great success. Early in the nineteenth century a lamp burning turpentine, under the name of "camphine," was invented that gave a good light and was smokeless; but like most others of its type, it was dangerous owing to its liability to explode. And it was not until methods of refining petroleum had been improved that "mineral-oil lamps"—the predecessors of the modern type of lamps—came into use.

The invention of this type of lamp was a relatively easy task—a simple transition and adaptation as processes of refining the oil were perfected. The principle of combustion was, of course, the same as in the Argand type of lamps burning animal and vegetable oils; but mineral oils are of such consistency that capillarity causes an abundant supply of oil to rise in the wick, so that clockwork and spring devices, such as were used in the Carcel lamps, could be dispensed with.