NUTRIA. The commercial name for the skins of gyopotamua Bonariensis, the Coypou of Molina, and the Quoiya of D'Azara. In France the skins were, and perhaps still are, sold under the name of racoonda ; but in England they are imported as nutria skins—deriving their appellation, most probably, from some supposed similarity of the animal which produces them, in appearance and habits, to the otter, the Spanish name for which is nutria. Indeed, Molina speaks of the coypou as a species of water rat of the size and color of the otter. In England, nutria fur is largely used in the hat manufacture, and has become, within the last 15 or 20 years, an article of very considerable commercial importance. The imports fluctuate considerably. In 1823, they amounted to 1,570,103 skins ; but they have not, in any other year, been much more than half that number. In 1826, they were only 60,871. In 1837 and 1838, the imports were, at an average, 358,280 skins a year. Those entered for home consumption pay a duty of lid. a skin. They are principally brought from the Rio de Is Plata. Nutria skins are very extensively used on the continent. Geoffrey mentions that, in certain years, a single French furrier (M. Beehem) has received from 15,000 to 20,000 skins.
Like the beaver, the coypou is fur nished with two kinds of fur—viz., the long ruddy hair, which gives the tone of color, and the brownish ash-colored fur at its base, which, like the down of the beaver, is of much importance in hat making, and the cause of the animal's commercial value.
The habits of the coypon are much like those of most of the other aquatic Rodent animals. Its principal food, in a state of nature, is vegetable. It affects the neigh borhood of water, swims perfectly well, and burrows in the ground. The female brings forth from five to seven at a time, and the young always accompany her.
The coypou is easily domesticated, and its manners in captivity are very mild.
OAK. The general Ilallg of a well known hard-wooded forest t.me, much cultivated for the purposes of timber, par ticulary in ship-building, and in other cases where much exposure to the weath er is required. There are several varie ties of this valuable tree ; but the com mon English oak (Quercus robur) claims precedence of every other of European growth. The knotty oak of England, the "unwedgeable and gnarled oak," as Shak speare called it, when cut down at a pro per age (from 50 to 70 years), is the best timber known. Some timber is harder,
some more difficult to rend, and some less capable of being broken across ; but none contains all the three qualities in so great and equal proportions ; and thus, for at once supporting a weight, resisting a strain, and not splintering by a cannon shot, the timber of the oak is superior to every other.
A fine oak is one of the most pictur esque of trees : it conveys to the mind associations of strength and duration which are very impressive. The oak stands up against the blast, and does not take, like other trees, a twisted form from the action of the winds. Except the ce dar of Lebanon, no tree is so remarkable for the stoutness of its limbs ; they do not exactly spring from the trunk, but divide from it; and thus it is sometimes difficult to know which is stem and which is branch. The twisted branches of the oak, too, add greatly to its beauty ; and the horizontal direction of its boughs, spreading over a large surface, completes the idea of its sovereignty over all the trees of the forest.
The oak is raised from acorns, sown either where the oak is to stand, or in a nursery whence the young trees are transplanted.
The color of oak wood is a fine brown, and is familiar to every one : it is of dif ferent shades • that inclined to red is the most inferior kind of wood. The larger transverse septa are in general very dis tinct, producing beautiful flowers when cut obliquely. Where the septa are small and not very distinct, the wood is much the strongest. The texture is alternate ly compact and porous ; the compact part of the annual ring being of the darkest colors, and in irregular dots, surrounded by open pores, producing beautiful dark veins in some kinds, particularly pollard oaks. Oak timber has a particular smell, and the taste is slightly astringent. It contains gallie acid, and is blackened by contact with iron when it is damp. The young wood of English oak is very tough, often cross-grained, and difficult to work. Foreign wood, and that of old trees, is more brittle and workable. Oak warps and twists much in drying ; and, in sea soning, shrinks about 1-32d of its width.