Candle

a cylindrical piece of wax, paraffin, or tallow, with a wick running lengthwise through its center. It is designed to give light in burning. In burning the flame melts the fat; the wick absorbs the melted fat and feeds it into the flame. The wick and the fat require to be well proportioned to give the best results. If the wick be too small the light will be dim and the flame too small to melt the fat fast enough. If the wick be too large for the candle the supply of fat will be insufficient to maintain a bright flame. The wick is usually of soft, twisted cotton string. In early England rushes were used for the wicks of rush lights. Scientists have tried, without marked commercial success, to invent a wick that would not need snuffing.

Tallow makes excellent candles. The wax known as spermaceti is from the sperm whale, and is the best material. Excellent wax for candles is made from palm oil. Paraffin is used most commonly in England. Dip candles are made by lowering the wicks into melted tallow or wax repeatedly, allowing each coating to cool and harden before dipping again. Molded candles are made by pouring melted tallow into cylindrical molds of pewter or tin through the center of which wicks have been drawn. The lower end of the mold is closed by a conical cap, in the center of which a hole is left for the wick. The wick is passed through this hole and knotted. The other end is held in place by fastening it to a cross stick. The heated tallow is poured into the mold surrounding the wick and is allowed to harden. The knot is cut at the lower end of the mold, the mold is warmed slightly, and the candle withdrawn. The candle is made up end down, with the top or conical end in the lower end of the mold. Usually a number of candles are molded at the same time. Wax is too sticky and contracts too much in cooling to be run in molds. The wax candles are made by dipping and then rolling to and fro on a flat table to give a smooth, even surface. Large wax candles, such as are burned on altars, are made usually by wrapping a sheet of wax around a wick and then rolling.

In burning, the melted fat is converted first into a gas, which forms a dark, cool spot around the wick. The light produced by a sperm candle seven-eighths of an inch in diameter, and burning 120 grains an hour, is taken as a measure of light giving. It is called a standard candle. A ten-candle electric lamp is one that gives as much light as ten of these candles.

The Chemistry of a Candle by Tyndall is an interesting book.

See Light; Electricity; Arcturus