14 
TIMBEK 
the harder wood than in that of a softer nature, in thin boards 
than in thick boards, in wide boards than in narrow boards 
or logs, but occurs in all timber, although no outward 
manifestation may exist. Pine, spruce, and coniferous 
timber, owing to its very regular structure, suffers less in 
seasoning than oak and other hard woods, because, although 
the same laws take effect, the softness of the material pro- 
bably allows the cell walls to be crushed by the contracting 
forces, and so the primary law is modified. Timber loses 
water more rapidly at the ends than on the longitudinal 
faces, and shrinks more quickly there and tends to split ; 
a wet board having one side exposed to the sun, the water 
is extracted from that side, and the board buckles. 
the joints were perfectly flush (Fig. 6), and were it not 
for the tongues and grooves the planks would often lift 
up ; the timber has " pined " or shrunk on drying, 
for however well seasoned timber may be when placed 
in the dry atmosphere of a dwelling-house — and much 
of it is not well seasoned — it will probably in time lose 
some more of its moisture and tend to shrink. Owing 
to its structure, as has been said, timber is not appreciably 
affected in length, that is, along the grain, by seasoning. 
Eondelet found many years ago that fir might shrink 
from to of its length, and oak from -^^ to 5^2- 
Mr. Hurst makes an allowance of ^ inch for northern 
pine and J inch for white deals nine inches in width, being 
■^jr and respectively, and recent American experience 
has shown that whilst the longitudinal shrinkage is usually 
Fig. 6. 
On examining floor- 
ing or panelling one 
often notices that there 
is an opening at the 
joints, although when 
originally laid or fixed 
