Teak
Tectona grandis, one of the most valuable timbers known; the wood of a large deciduous tree (natural order Verbenacea) with leaves from 10 to 20 inches in length, and from 8 to 15 inches in breadth. The tree, which has small white flowers in panicles, is found in central and southern India, where however, it is now scarce in some localities in which it was formerly plentiful. There are extensive forests of it in Burma and Siam, and it extends into Java and some neighboring islands. In India growing teak is placed under the management of a conservator of forests, and very little is now exported from that country. The wood is of a quiet yellow color, tending to brown, and like many other kinds of timber has a characteristic odor. It is classed as a hardwood, though it is only of medium hardness, taking, however, a good polish; and it is straight grained and strong.
Teak does not shrink much in seasoning, and it is believed to expand and contract less by differences of temperature than most woods.
A sticky elastic extract, to some extent resembling india-rubber, is obtained from teak by treating the wood with naphtha or ether. It is probably this which prevents iron in contact with it from rusting; hence its use for backing the armor plates of warships.
The pores of the wood are sometimes filled with a white substance, which has been ascertained to be phosphate of lime (calcium phosphate). There is a high percentage both of this substance and of silica in the ash of teak, and this no doubt explains why carpenters and other White tradesmen consider it gritty. White ants rarely attack the wood if it is sound, but nevertheless logs of it are often badly worm-eaten.
In India teak is used for all kinds of work where strength and durability are required, such as for building ships, houses and bridges, also for the construction of railway carriages and furniture. In England it is largely employed in The leaves of the tree ship-building. yield yield a a red dye. Being of large size they are used in India for plates and for thatching.
African teak (Oldfieldia Africana) is imported from the W. coast of Africa; it is also a valuable timber, but less so than true teak.