CORK

( Liége , Fr.; Kork , Germ.) is the bark of the quercus liber , Linn., a species of oak-tree, which grows abundantly in the southern provinces of France, Italy, and Spain. The bark is taken off by making coronal incisions above and below the portions to be removed; vertical incisions are then made from one of these circles to another, whereby the bark may be easily detached. It is steeped in water to soften it, in order to be flattened by pre ure under heavy stones, and next dried at a fire which blackens its surface. The cakes are bound up in bales and sent into the market. There are two sorts of cork, the white and the black; the former grows in France and the latter in Spain. The cakes of the white are usually more beautiful, more smooth, lighter, freer from knots and cracks, of a finer grain, of a yellowish gray colour on both sides, and cut more smoothly than the black. When this cork is burned in close ve els it forms the pigment called Spanish black . This substance is employed to fabricate not only bottle corks, but small architectural and geognostic models, which are very convenient from their lightne and solidity. The cork-cutters divide the boards of cork first into narrow fillets, which they afterwards subdivide into short parallelopipeds, and then round these into the proper conical or cylindrical shape. The bench before which they work is a square table, where 4 workmen are seated, one at every side, the table being furnished with a ledge to prevent the corks from falling over. The cork-cutter’s knife is a broad blade, very thin, and fine edged. It is whetted from time to time upon a fine-grained dry whetstone. The workman ought not to draw his knife edge over the cork, for he would thus make mi es, and might cut himself, but rather the cork over the knife edge. He should seize the knife with his left hand, rest the back of it upon the edge of the table; into one of the notches made to prevent it from slipping, and merely turns its edge sometimes upright and sometimes to one side. Then holding the squared piece of cork by its two ends, between his finger and his thumb, he presents it in the direction of its length to the edge; the cork is now smoothly cut into a rounded form by being dexterously turned in the hand. He next cuts off the two ends, when the cork is finished and thrown into the proper basket alongside, to be afterwards sorted by women or boys. Of late years a much thicker kind of cork boards have been imported from Catalonia, from which longer and better corks may be made. In the art of cork-cutting the French surpa the English, as any one may convince himself by comparing the corks of their champagne bottles with those made in this country. Cork, on account of its buoyancy in water, is extensively employed for making floats to fishermen’s nets, and in the construction of life-boats. Its impermeability to water has led to its employment for inner soles to shoes. When cork is rasped into powder, and subjected to chemical solvents, such as alcohol, ., it leaves 70 per cent. of an insoluble substance, called suberine . When it is treated with nitric acid, it yields the following remarkable products:—White fibrous matter 0·18, resin 14·72, oxalic acid 16·00, suberic acid (peculiar acid of cork) 14·4 in 100 parts.