Part V.] Sweet; On Air Seasoning of Indian Timbers. 7 
(Hi) Definition of Seasonfjg Defects as Used at Pinal Inspection. 
For the purpose of the inspection the defects attending the sea- 
soning as they appeared in the converted timber were taken as 
follows : — 
Surface Crack (sometimes called sun cracking ”) — A rupture 
in and through the surface usually across the annual growth rings ; 
caused by more rapid drying from the surface than from the inside 
of the piece. 
Split. — Complete separation of the fibres with the grain starting 
from the end of the piece and extending toward the centre ; caused 
by more rapid drying from the end sections than from the other 
surfaces. 
Shake. — Complete separation of the fibres either with or across 
the growth rings resembling cracks and splits except that the cause 
as it appears in the converted timber is plainly attributable to an 
inherent weakness or an original defect in the wood rather than the 
result of unequal drying. Shake is aggravated by the seasoning, but 
it is present in the wood before seasoning begins. 
Warp. — Curvature across the width of a piece of timber as detect- 
ed by laying a straight edge across the broad surface from edge to 
edge. Warp is caused by unequal shrinkage or expansion across the 
grain, due either to the structure of the wood, method of sawing, or 
to uneven drying, or a combination of the three. 
The term is commonly used in this connection to indicate cur- 
vature in any direction or plane, but for the purposes of this study 
its application has been limited as described above. 
Cup. — Curvature along the length of a piece as detected by lay- 
ing- a straight edge along the broad surface from end to end. Cup is 
caused by unequal longitudinal shrinkage or expansion due to the 
structure of the wood, or uneven drying, but more often to some 
mechanical effect such as improper support in piling. 
Twist. — Curvature both across the width and along the length of 
a piece combining the effects of warp and cup, usually resulting from 
the seasoning of wood with interlocked grain or from uneven piling. 
Both the terms twist and cup denote conditions which are usually 
included under the general term ivarp. 
Spring. — Curvature along the length of a piece as detected by 
laying a straight edge along one edge from end to end. Spring is 
caused by unequal longitudinal shrinkage, particularly as between 
the 'heartwood and sapwood in quarter sawn boards. 
Decay. — Breaking down of the wood fibres under the action of 
fungi as shown by actual disintegration or the characteristic lifeless 
or punky appearance, or the presence of dark or black lines. 
Mould. — Superficial growth of the mycelium of certain groups of 
fungi upon the surface of the wood. Although these moulds as a rule 
[ 153 ] 
