Page:Popular Science Monthly Volume 27.djvu/590

572 part of the paint which it does not decompose. All of the best anti-fouling paints depend for their efficacy on some compound of mercury or copper, while the action of iron is very strong in contact with both these metals; hence perfect isolation of the paint from the iron is necessary to make them of any value. Besides paints of magnesia and alumina, spirit and benzoline varnishes, powdered coke, anthracite or coal, lime, cement, and various kinds of silicates, mixed or suspended in oils, have been found good in greater or less degrees for these purposes. Zinc oxide also has some slight merits, while red lead paint, which has been used, is "out of the question. It is bound to give out after a certain time; and, besides, the metal beneath is corroded."

The Teak-Tree and its Timber.—The teak-tree is found growing in various places in the East Indies, through a region reaching from the eighth degree of south latitude in Java to about the Tropic of Cancer, and of undefined extent in longitude, but not farther west than 72° east. Its vertical habitat is about 3,000 feet above the level of the sea, but seldom below 2,000 feet. Its northern limit is in Bundelcund, where it is found in specimens not tall, at elevations rising as high as 4,000 feet. It grows in groups, a circumstance which is very convenient in trade. The wood is held in the highest esteem by ship-builders, and is preferred to any other for the backing of ironclad vessels. It shrinks hardly any, is considered the strongest and most durable timber of India, or perhaps of the world, and resists the attacks of white ants. The qualities of the timber vary greatly according to the character of the soil on which it grows, sometimes so much as to induce the belief in different species; but close examination has shown that, though varieties may exist, there is but one species. In Java, the Government have control of 1,650,000 acres of teak, besides new plantations. The planting and raising the trees, and mode of felling, classing, and measuring the timber are carefully regulated. Forest reserves of considerable extent exist in various parts of India, from some of which specimens have been shown more than 100 feet lorn', and 93 and 100 inches in circumference at the base. One of the chief sources of supply is British Burmah, where the total area of the reserve forests is 3,274 square miles, and 836 square miles were added during 1881-82. Nineteen thousand teak-trees were girdled, and 130,000 tons or 6,500,000 cubic feet of the timber were exported during this year from Rangoon and Maulmain. The principal forests are near the Irrawaddy River, where water conveyance is easy and ship-building is prosperous. A very fine plantation has been established at Nilambur, on the river Beypore, in Malabar, where 100 acres are planted each year, and there are now about 1,800,000 trees. An increasing source of supply is also being developed in Siam. According to Colonel Beddome, the growth of teak is very rapid, compared to that of the oak. The growth in the sapling state may be calculated at about one or two cubic feet a year; but after thirty years it is immensely accelerated, and an increase of five cubic feet has sometimes been remarked in a year. Several other trees, but little known as yet, are mentioned as nearly equal in value to the teak. The takieng, besides being a rival to it in size and quality, possesses the advantage of being easily bent by artificial means. Sir Robert Schomburgk saw a log of it measuring 135 feet, perfectly sound, in the building-sheds of the King of Siam. The red peema of Burmah and Tenasserim is considered equally useful with teak, as is also the touk-kyan, with its dark-brown wood. Angely is well suited for the floors and bottom-planking of ships, but has to be used with copper, as it corrodes iron. Jackwood, a tree of the same family (Artocarpus), furnishes an excellent fancy and furniture wood, and is admirably adapted for boat-building. An Australian timber called tuart is believed by Mr. Simpson to be superior to all others for the backing of armor-plated vessels, as it can not be split by any possible means.—From a paper read by Mr. P. L. Simmons before the Society of Arts.

The Duk-duk.—According to Mr. Wilfred Powell's "Among the Cannibals of New Britain," affairs in the Duke of York Islands are regulated by an officer called the duk-duk, who appears to combine in