36 
Indian Forest Records. 
[VOL. II. 
tangential splitting, and it is this fact which is generally responsible for 
any great excess of force required for splitting in a radial, as compared 
with a tangential direction. 
According to Gayer, European hard woods are more fissile when wet 
and soft woods are more fissile when di’v^, 
(d) Moisture. mi • • i • <> t t ' 
1 his IS not borne out in the case or Indian 
woods by the present tests, for of the 16 woods tested in this respect 
all split more easily when dry than when wet except one, Sterculia villosa, 
which required the same splitting force for green and dry wood. The 
green and dry specimens of each species were cut from the same log 
from a freshly-felled tree, some being tested while quite green and the 
remainder being kept till thoroughly seasoned. The explanation why 
green wood splits with more difficulty than dry wood no doubt is that the 
moisture toughens the fibres : hence, as we might expect, the greatest 
disparity in the relative forces required for splitting green and dry wood 
exists in cross-fibred woods, such as Cedrela Toona, Shorea rohusta, 
Bombax vialaharicun , Anogeissns latifolia, and Dalbergia Sissoo, where 
the cross-fibres have to be cut across or torn apart with difficulty, whereas 
in straight-grained woods such as Kydia caJyeina, Cassia FtstiUa, Acacia 
Catechu, Sterculia villosa 2Mdi others the disparity is small or non-existent. 
(3) Surfaces produced by Splitting. As a general rule the tangen- 
tial surface of fission is smoother and straighter than the radial surface, 
this being particularly marked in the case of cross-grained woods. In the 
remarks column of the Appendix will be found notes regarding’ the surfaces 
produced on the various specimens tested, these being also illustrated in 
Plates I and II. 
There are some characteristic types of surface produced by the splitting 
of certain classes of wood, the following being worthy of special remark : — 
{a) Conifers. As a general rule the radial surface consists of 
parallel ridges and furrows corresponding to the annual rings, 
while the tangential surface is apt to curve in the direction of 
the annual rings, being smooth until it intersects an annual 
ring, when it becomes broken. 
{h) Gardenias have a characteristic flaky or almost conchoidal frac- 
ture, the surface being covered with iiTegular hollows and 
undulations ; this is usually more marked on the radial than on 
the tangential surface. This structure is noticeable also in 
Schrebera swietenioides. 
