The American Cyclopædia (1879)/Cork (bark)
CORK (Lat. cortex, bark), the soft elastic bark of a species of oak (quercus suber) which grows abundantly in Spain, Portugal, Italy, Algeria, and the south of France. Commerce is indebted to Portugal for its largest supply. When the tree is 15 years old the barking is commenced, and may be repeated every eight or ten years afterward, the cork increasing in quantity though not in quality at each operation. Trees thus barked will, it is said, live 150 years. The cork is removed from the trees in July and August. This is done by making incisions around the tree and longitudinally to the root, when the pieces are easily detached. These are then soaked in water, pressed under heavy weights, dried before a fire, and stacked or packed in bales for exportation. The cork cutters divide the sheets of cork into narrow strips, and, after cutting these of the proper length, round them into a cylindrical form with a very sharp, thin-bladed knife. Of late years, however, corks are made in vast numbers by a machine of American invention, with which a man will make more in a day than he could by hand in 20 days. The hand-made corks, however, are the best. Spanish black is made from the burnt parings of cork. Cork and its uses were known among the ancients, but it does not appear to have been common until the 15th century, when glass bottles first came into general use. Cork is employed in various ways, but especially for stopping vessels containing liquids, and, on account of its buoyancy in water, in the construction of life boats. It is also used in the manufacture of life-preservers and cork jackets. This invention appears to be of very early date, as Plutarch in his life of Camillus refers to it. About 6,000 tons of cork bark are annually shipped from cork-producing countries, and an equal quantity used for home consumption.