Page:Cassells' Carpentry and Joinery.djvu/69

Rh merchant may fairly claim that he acts justly by his customer if he supplies him with a moderately dense, sound quantity of Cuban or St. Domingo mahogany, and has not supplied him with baywood (Honduras mahogany) nor any of the many other so-called mahoganies, the marked characteristics of which differ widely from Cuban mahogany. Such spurious mahoganies are, for example, the so-called African mahogany (Khaya Senegalensis) or the wood that is known as Australian mahogany (Dysoxylum Fraserianum).

In the following list the timbers are stated in order of superiority for the purposes named. All the timber should be specified according to the precise quality required, and not merely as "the best."

Dock Gates.—Greenheart, oak, creosoted Memel. The specification of the 60-ft. entrance lock gates at the Victoria Dock, Hull, provided for ribs, heads, and heels of single squared timbers, either of English oak of the very best and quickest grown timber, or of African oak, but no mixture of the two. The planking was specified to be of greenheart.

Doors External for Public Buildings.—Oak used most frequently, next in order mahogany, teak, and pitchpine.

Doors Internal for more Important Buildings.—Oak, mahogany, teak, walnut, pitchpine. Other hardwoods are also used, according to, or in keeping with, other internal fittings. For ordinary buildings, yellow deal for framing and yellow pine for panels.

Floor Boards.—Oak, pitchpine, Stockholm or Gefle yellow deal; and for upper floors, Dram or Christiania white deal. For common floor-boarding, Swedish or Norwegian yellow or white deal.

Floor Joists.—Russian deals make the best joists, as they are straight-grained and free from knots, sound and tough. Baltic fir is cheaper and next best. Swedish and Norwegian not reliable.

Half-timber Framing.—Oak is best, as it resists decay the longest, and can be obtained naturally shaped in curves or straight, as may be required. The colour and texture are also suitable for architectural effect. Teak is good, but does not weather quite so good a colour; it is apt to split with nailing. Larch is next best.

Pile Foundations.—Greenheart, oak, elm, creosoted Memel, alder. Greenheart is undoubtedly best, but the cost is prohibitive except for marine work, where it is sometimes essential, as sea-worms will not attack it. Oak is next best when it can be afforded. Memel fir (Pinus sylvestris) in 13 in. to 14 in. whole timbers, creosoted or in its natural state, is the most suitable under ordinary circumstances, owing to its convenient size, length, and general character. Riga fir is generally too small, and Dantzic fir too large and coarse. Pitchpine is considered suitable by some; its chief advantage is the large size and great length in which it may be obtained. American elm and English elm, beech, and alder are suitable if wholly immersed, but not otherwise.

Planking to Earth Waggons.—Elm, with ash for shafts, if any.

Roof Trusses.—Oak, chestnut, pitchpine, Baltic fir (Dantzic, Memel, or Riga). For tie-beams to open timber roof 40-ft. span pitchpine is best, as it can be obtained free from knots, in long straight lengths, and the grain is suitable for exposure either plain or varnished. Oregon pine is suitable for similar reasons, but not so well marked in the grain. Riga fir is good material for roof timbers, but difficult to obtain in long lengths. For tie-beam of king-post roof truss, the same as above, or pitchpine, if it is to be wrought and varnished.

Shop Fronts.—Mahogany is the favourite material, and weathers well if kept French polished; black-walnut and teak are perhaps next in order.

Treads of Stairs.—Oak, pitchpine, Memel fir, ordinary yellow deal.

Weather-boarding.—Oak is best under all circumstances, but is expensive. Larch (Larix Europoea) perhaps stands next, as it resists the weather well and bears nails without splitting. Ordinary weather-boarding consists of yellow deal from various ports—say, four out of a 2½-in. by 7-in. batten or 3-in. by 9-in. deal cut feather-edged. For work to be wrought and painted, American red fir is clean-grained and cheap. For very common rough work