Distilling

separating one substance from another by evaporation. Nature carries on distillation on a grand scale. The heat of the sun causes the water of the ocean to rise or evaporate, leaving the salt, the iodine, and other substances behind. The vapor is cooled in the upper regions, and clouds of distilled water are formed. If brine be heated in a kettle the vapor may be caught in a handful of wool, supported by a few sticks laid across the top, and water thus separated from the salt--distilled water--may be squeezed from the wool. If we fit a tea kettle with an airtight cover, and convey the vapor from the spout through a coil of tubing so that the steam may cool and trickle drop by drop into a cup set to catch it, we have a still. If the conducting coil of tubing pass through running water to keep it cool the three essential features--the retort, the condenser, and the receiver--of a modern still are present. If the liquid obtained be not pure it may be redistilled. Distilling proceeds on the principle that of substances in solution, that is to say, in a liquid form, some vaporize or evaporate more readily than others. Alcohol vaporizes more readily than water, and will rise from a mixture, leaving the water behind. If water, salt, and alcohol be mixed, water and alcohol together may be secured by vigorous heating. A second distillation with gentle heat will drive the alcohol over the divide, and leave the water undisturbed. Sometimes the substance left behind is quite as desirable as the substance that is distilled. When the flow of the Georgia pine is placed in a still both products of distillation are desired. The oil of the pine, or turpentine, which is distilled, and the gum or resin, which is left behind, are valuable.

Distillation was employed by the ancients in the preparation of oil from the wood of cedar. Whether the alchemists of the Middle Ages thought that some occult power might lie in animal shapes, or whether the animals suggested shapes for their retorts, their stills are pictured as having the odd forms of a clay ostrich, a pelican, a goose, a standing bear, etc.

Distillation has a wide application in modern industry. Many devices are employed, but they all contribute to the three simple essentials,--heating, cooling, and catching.

See Perfumes; Oils; Brewing; Turpentine; Peppermint; Whiskey; Alcohol