Page:The Oak.djvu/159

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141
OAK TIMBER.

elasticity = 129·8 kgr., and the breaking limit 0·406 kgr.

The absolute tenacity in the transverse direction is given as 0·44 to 0·61 kgr.

In the case where pressures are applied in the direction of the length of the fibers the limit of elasticity = 2·09 to 2·22 kgr.; the modulus of elasticity, 933 to 1,250 kgr.; and the absolute resistance, 2·58 to 3·64 kgr.

Flexibility.—The limit of elasticity = 1·77 to 2·71 kgr.; modulus of elasticity, 620 to 735 kgr.; resistance to bending, 4·53 to 6·18 kgr.

Torsion.—Oak warps considerably unless carefully seasoned. Limit of elasticity = 0·4 to 0·54 kgr.; modulus of elasticity, 612·5 to 785 kgr.; resistance to torsion, 0·75 to 0·97 kgr.

Resistance to shearing-stress, in the direction of the fibers = 0·61 to 0·97 kgr.; perpendicular to them, 1·9 to 3·49 kgr.

(7) Resistance to Splitting.—Oak is easily split into tolerably smooth and even staves, and is much employed for this purpose.

(8) Hardness.—Oak is neither the hardest and heaviest nor the most supple and toughest of woods, but it combines in a useful manner the average of these qualities. Good oak is hard, firm, and compact, and with a glossy surface, and varies much; young oak is often tougher, more cross-grained, and harder to work than older wood. According to Gayer, if we call the resistance which the beech offers to the saw, applied trans-