Page:Cassells' Carpentry and Joinery.djvu/57

Rh Doatiness.—This is a speckled stain found in beech, American oak, and other timber, due to incipient decay. It is produced by imperfect seasoning or by exposure for a long period to a stagnant atmosphere.

Fig. 167—Sapwood in Balk.

Fig. 168.—Star-shake in Log.

Dry Rot.—If the balks have been stacked on land with insufficient ventilation, the growth of a fungus over them, like white or brown roots, may indicate that dry rot has already begun, although it is chiefly found under kitchen floors.

Foxiness.—A reddish or yellowish brown tint in the grain, caused by incipient decay.

Fig. 169.—Star-shake in Balk.

Heart-shakes.—These are splits or clefts occurring in the centre of the tree, as in Figs. 165 and 166. They are common in nearly every variety of timber, and are very serious when they twist in the length, as they interfere with the conversion of the tree into boards or scantlings. They sometimes

Fig. 170.—Twisted Fibres.

divide the log in two for a few feet from the end.

Knots.—Large, or dead and loose knots are objectionable, as they weaken the timber, and are unsightly. A timber pile, in which knots occur diagonally, is liable to be sheared through the knots or severely damaged by the blows of the ram. Dantzic timber has the largest knots, spruce the hardest.

Rind-galls.—These are curved swellings caused by the growth of new layers over a part damaged by insects, or by tearing

Fig. 171.—Upset or Crushed Fibres.

off or imperfect lopping of a branch. These are shown by the grain being irregular and vacuous.

Sapwood.—This occurs more in some trees than in others—say, Dantzic much, pitch-pine little. It may be known by its greenish tinge, and holding the water longer than the sound parts after having been wet. If creosoted, the sapwood is as lasting, but not so strong as the heartwood. It generally occurs at the corners only of the balks, which arises from the desire to save as much timber as possible. (See Fig. 167.)

Fig. 172.—Waney Edge in Balk.

Star-shakes.—When several heart-shakes occur in one tree (see Figs. 168 and 169) they are called star-shakes from the appearance produced by their radiation from the centre.

Thunder-shakes.—These are irregular fractures across the grain, occurring chiefly in Honduras mahogany.

Twisted Fibres.—These are caused by the tree being twisted in its growth, from the action of the wind upon the head. Timber so affected is not suitable for cutting up into joists or planks, owing to the fibres running