140 THE OAK 
the difference would hold if sufficiently numerous com- 
parisons were made. 
(5) Swelling may be regarded as complementary to 
shrinkage. It has been found that it oak wood is 
allowed to absorb water until thoroughly saturated it 
will increase from 0°13 to 0-4 per cent. in length, and 
be distended radially from 2°66 to 3-9 per cent., or tan- 
gentially 5°59 to 7°55 per cent., according to age and 
condition, young wood swelling more than old. It has 
also been found that the total volume increased from 5:5 
to 7°9 per cent., and the weight from 60 to 91 per cent., 
on complete saturation. 
(6) Hlasticity and Tenacitynx—Oak is very elastic, 
and easily bent if steamed, and it does not readily 
splinter. When pulled in a direction parallel to the 
length of the structure the absolute tenacity= 2°23 to 
14°51 kor.—.e. it took a pull equal to this weight per 
1 sq. mm. of section to pull the wood asunder. 
The limit of elasticity corresponds to a load of 2°72 
to 3°5 kgr., according to various authorities, the speci- 
men lengthening ;4,th in the former case. 
The modulus of elasticity is given as 826 to 1,030 
ker., and the breaking limit as 4°66 to 6°85. 
When the pull is in a direction across the length of 
the fibres, the results differ according as the load is 
applied so as to act radially or tangentially. 
When acting radially the modulus of elasticity is 
given as 188-7 kgr., and the breaking limit as 0°582 ker. 
When acting parallel to a tangent the modulus of 
