582. This timber, which has been imported in considerable quantities from Sierra Leone, is used for the same purposes as oak, but chiefly for ship-building. The colour of the wood is a moderately deep yellow or greyish brown. The texture is uniform; the annual rings are not very distinct, but the smaller medullary rays are strong and numerous. The wood is dense, hard, and brittle; the taste bitter; but the seasoned wood has no sensible smell. It appears to split much internally while seasoning, and is liable to the attacks of worms and insects. In the form of plank it is apt to warp, and it swells with moisture, which in drying out again causes the timber to split.

The Turtosa can be obtained in balks of considerable length free from knots.

According to the author's experiments made in 1821 the cohesive force of a square inch of Turtosa is 17,200 lbs, and the weight of a cubic foot dry is from 58 to 61 lbs.

The weight of the modulus of elasticity for a square inch is 1,728,000 lbs.

A bar 1 foot long between the supports and 1 inch square, broke with 954 lbs. applied in the middle, and bent 1/480 of its length, or one-fortieth of an inch by a weight of 100 lbs.

According to experiments made by Sir F. Smith, the cohesive force of a square inch of Turtosa is 21,000 lbs., that of oak being 19,900 lbs., and fir 12,000 lbs.

The resistance to compression of specimens 4 feet long and 1 1/2 inch square, was for Turtosa and English oak as follows: -

Resistance to crushing of short specimens of Turtosa made by Mr. Renton: -