The chief varieties of this wood are English, Stettin, Wainscot, and American. It is very hard, tough, close, and durable, and is used by both carpenter and joiner. It is of a light brown colour, has medullary rays in it to a conspicuous degree, in addition to the annual rings, which should be close and regular to denote the best quality.
The English variety is obtained from either the "stalk" or "cluster fruited" trees, the latter being the darker in colour, heavier, tougher, and more durable quality of the two. Both kinds are much used in this country, where strength and durability are the chief requirements, especially for window and door sills, wall-plates, roofs, steps, posts, fencing, etc. It is hard to work, especially when young and wet, being more of a carpenter's than of a joiner's wood, is very elastic, and can be easily bent when steamed.
Its weight is about 40 cubic feet per ton, and its compressive strength may be taken at 13 cwt. per square inch; bearing strength at 25 cwt., and tensile strength at 16 cwt. These results are based on the same standard, or working stress, as other safe quotients given in these notes.
The gallic acid which oak contains corrodes all iron with which it comes in contact; wherefore, screws, bolts, etc., to be used with it, should always be galvanised.
Stettin oak, so called after the port whence it is shipped, is at first sight similar to the English species, and is very often substituted for it, but it is not nearly so strong or durable. It is softer and easier to work, though inclined to be woolly. Loose dead knots and decayed pores are very often met with in it, and when it is wet and unseasoned it gives off a sour odour. It is imported in logs, and is employed for the same uses as the English.
American oak has a pink tinge in it, and is similar in texture to the last named, though sound, hard, tough, and elastic. It is used as a substitute for English oak.
Wainscot oak is chiefly shipped from the Baltic ports, Riga and Dantzic. It is imported into this country in logs cut "on the quarter." This kind of oak is grown chiefly in Poland and Austria, and is essentially a joiner's wood, being more expensive than the other kinds, and used only for best internal finishings. It is hard, of a light brown colour, with a close, compact, and even grain, though it is kinder in nature and less durable; knots are seldom met with in it, and it is the absence of knots that leads some people to note the difference between it and the best Stettin, which is, in fact, very much like it in most other respects. Wainscot is full of little pores, and sometimes white specks; the medullary rays are very conspicuous, if it is properly converted "on the quarter," and give it a beautifully figured appearance. The "Crown Riga" is often specified as the best quality. It is used for all kinds of joinery and cabinetwork, as well as for flooring, and will take polish well.
Teak is both a carpenter's and joiner's wood, found in Southern India and Burmah, where it is sometimes called the Indian oak. It is very straight in the grain, has no medullary rays, and is of a warm brown colour, tinged with yellow, in contrast to the purple tinge of elm. Teak is very brittle, whereas oak is tough. It has a peculiar smell, but does not corrode iron; it never swells, and is as strong as oak, free from knots, but subject occasionally to shakes at the heart. It is used for window-sills, treads to steps, bumping-blocks, and the best kinds of joinery. Railway companies use a great deal of it for carriage doors, on account of its non-liability to swell, and it is much used in shipbuilding. It will polish well.
Greenheart, found in the North of Southern America, is very often used as a substitute for teak, being much cheaper, and at the same time possessing the qualities of teak - viz., a fine, hard, and close grain, and great strength and resistance to crushing.
Mahogany is imported in very large square but short logs from Honduras and Cuba, the former being very much softer than the latter, and easier to work; in fact, some of it, called "Bay wood," is very little more costly to work than deal. In colour it is a light mixture of red, brown, and yellow; shiny, close, hard, and yet kind in grain, free from the general defects, but it will not weather, and is only used for joinery, table-tops, handrails, and internal best finishings. It will take a nice polish.
Cuba, or Spanish mahogany, is considerably harder than the last-named variety, darker and richer in colour, full of little pores and silvery specks - due to the presence of lime - which dull the joiner's planes. It is far superior to the other kinds, more expensive, harder to work, and is only used for the best polished work.
Walnut is of two kinds, Italian and American, very different from each other in quality and nature. The Italian is really a cabinet-maker's wood, though occasionally used in the best of joiner's work. It is much harder, closer, and of a brighter colour than the American. It is principally used for piano cases and best cabinetwork; while the American is made up into doors, windows, dadoes, and other best joinery finishings - the colour being a dull light mauve, though it is often called "American brown walnut," being imported from New York, while the "American black walnut" is imported from Quebec in Canada.
Beech, the only other wood which is really of any great use to the building trades, is a hard, close, light-coloured, and speckly wood, obtained from the English tree of the same name. It is chiefly used for sinks, drainers, etc., where its hard, non-absorbent properties are of advantage; and the handles of carpenters' and joiners' tools are made of this kind of wood.
Aah, an English-grown wood, is remarkable because it has apparently no sapwood. It is tough, though easily worked, and very durable in a continually dry atmosphere. It is of a brownish-white colour, and used chiefly by cabinetmakers, on account of its elasticity and flexibility, which render it unsuitable for building purposes.
Sycamore is a white or yellow-coloured wood, from the plane tree, found in the North of England. It is of a very compact, firm, and durable quality, and will not warp. Builders scarcely ever use it, except for patterns.
Birch is another hard, English-grown wood, being more of a builder's wood than either of the two preceding kinds, as it is often used for handrails, stair-treads, etc. It is of a light yellow, speckly colour, very close and even in the grain, and sound. It is much used in the manufacture: of furniture.