Chap. XXII.

TIMBER AND ITS PROPERTIES.

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less liable to shrink than the other kinds of deal, nor will it split with the grain to anyconsiderable length, from the crossing of its fibres.

Lignum l~itce, is a hard wood much used by millwrights; its specific gravity is 1*333,andthe weight of a cubic foot is 83*31 pounds avoirdupois.

Lime is a beautiful ornamental tree, and grows to a prodigious size, acquiring adiameter of 15 or 16 feet: the wood is of a pale yellow colour, close-grained, soft, light,and smooth in its texture, admirably adapted for the purposes of fine carving and cabinet-work.

Maple ( Acer Pscudo-platanus ) is found growing in mountain districts, and valuable forits lightness, and not being subject to warp or split it will take any colour and a finepolish.

tbs. oz.

When green, it weighs - - - - 61 9 per cubic foot,

dry, - - - - - -51 15 —

Sugar Maple, ( Acer saccharinum). The bird’s-eye maple, from the beauty of its grainand the shades of its spots is much employed for veneering ; by sawing the timber nearlyparallel with the concentric rings, the effect of its marking or pencilling is much improved :in America wheelwrights employ it, after giving it a seasoning for three years, and whenconstantly under water it will not readily perish.

Mahogany (Swietenia Mahogani ) is the produce of America and the West Indies , and itis principally imported from Honduras and Campeachy : that imported from the islandsis called Spanish mahogany ; the annular rings are not very distinct, it has no large septa,and warps less than most other woods : that brought from Honduras is the production oflow marshy ground, and is coarse, soft, and spongy, whilst the most beautiful mottled andveined is grown upon high ground, and is often very valuable, being cut into veneerseight or ten to an inch : worms will not attack it when properly seasoned, but exposure toour climate soon destroys it; it is much used in parts of machinery, furniture, and por-tions of joiners’ work, where ornament is studied. The weight of a cube foot is from 35 to53 lbs.

Oak , (liohur Quercus, or peiuliculata )_The common English Oak acquires considerable

size, but does not grow so tall as some of the other species ; its wood from its hardness isdifficult to work, though preferred, where solidity is required: the Greeks call thisspecies drys ; the leaves have short footstalks, and the acorns long ones; the grain of thewood is fine, of a reddish tinge, free from knots, and will cleave easily into pales or lathes ;where stiffness is an object, as in guiders or joists, it is very useful, as it will not bendreadily.

Ibs. cz.

When green it weighs * - - - 76 13 per cube foot,

half dry - - - - - 65 9 —

perfectly dry - - - - - 52 13 —

Oak — ( Quercus sessilijlora ). — In this variety of oak, the wood is of a softer quality,and consequently yields more readily to the tools of the workman; the leaves areattached by long footstalks, and the acorns set close to the branches, differing in thisparticular from the specimen above described: the timber is subject to warp and split, butin consequence of its elastic qualities, it is highly prized for ship-building, its toughnessand strength recommending it for that purpose; its hardness is sufficient for all ordinarypurposes where oak is required. The grain of this variety bearing a strong resemblanceto that of the chestnut, it is often mistaken for it, and it will last a long time, whenpreserved either entirely dry or under water.

lbs. oz.

When green it weighs - - - - 80 5 per cube foot,

half dry - - - - -67 12 —

perfectly dry - - - - -51 10 —

Among the other varieties of the oak is the Etumodrys, which grows more lofty thanthe robur ; the Esculus, or holm oak, mentioned by Vitruvius as having “its elementscomposed of earth, air, fire and water, in more equal proportions than others, is of great usein building, but damp soon destroys it; and its air and fire being driven oft’, it soon rots.”The Quercus Ilex, or holm oak, is probably the Cerrus of Vitruvius ; it produces acornssimilar to that of the Esculus, which are also edible ; the leaves continue during the winter,and the tree lives to a great age; its bark is very thick ; the wood takes a fine polish;like other hard specimens it splits and warps in drying, though it possesses considerableflexibility ; it weighs 70 lbs. the cube foot.

Oak ( Quercus alba), or American oak, and the Quercus rubra of Canada , are of quickgrowth, but not so durable as the British oak : wainscot is obtained from the Riga oak,which is very clean and free from knots, and much in request by the joiner, forming goodfloors and wainscoting.

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