OAK TIMBER 141 
elasticity = 129°8 kgr., and the breaking limit 0-406 
ker. 
The absolute tenacity in the transverse direction is 
given as 0:44 to 0°61 ker. 
In the case where pressures are applied in the direc- 
tion of the length of the fibres the limit of elasticity = 
2:09 to 2:22 ker. ; the modulus of elasticity, 933 to 1,250 
ker.; and the absolute resistance, 2°58 to 3°64 ker, 
Flewibility.— The limit of elasticity = 1:77 to 2°71 
ker. ; modulus of elasticity, 620 to 735 kgr.; resistance 
to bending, 4°53 to 6:18 ker. 
Torsion.—Oak warps considerably unless carefully 
seasoned. Limit of elasticity = 0-4 to 0°54 ker.; 
modulus of elasticity, 612°5 to 785 ker.; resistance to 
torsion, 0°75 to 0:97 ker. 
Resistance to shearing-stress, in the direction of the 
fibres = 0°61 to 0:97 kgr.; perpendicular to them, 1:9 
to 3°49 ker. 
(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 
