8 
Indian Forest Records. 
[VOL. IX 
do not penetrate the wood or cause actual decay, they usually accom- 
pany and cover the growth of wood destroying fungi and are of signi- 
ficance in that the conditions favourable to the growth of the one are 
also conducive to the growth of the other. 
Discolouration . — A variation from the normal colour of the wood 
caused by a chemical change due to oxidation, or the growth of fungi 
or bacteria on the surface of the wood or penetrating the interior. 
Insects . — The boring, pitting, or further destruction of the wood 
by the action of insects. 
(iv) Determination of Degree of Seasoning. 
As a further and very important criterion of the seasoning, mois- 
ture tests were taken of representative pieces from each experiment 
and species. The moisture content was taken as the difference be- 
tween the original (current) weight and the oven-dry weight expres- 
sed in per cent, of the oven-dry weight of an especially prepared sec- 
tion of the wood under test. These determinations in most cases 
were made by cutting and weighing sections in the field at the time 
of inspection and then baking them and making the final weight de- 
terminations in the chemical laboratory at Dehra Dun. In some 
cases, where the original weights could not be taken in the field, 
borings from the pieces to be tested were put into a tightly stopper- 
ed glass bottle and sent to Dehra Dun for weighing, baking, and 
reweighing. 
(v) System of Grading Timber at Final Inspection. 
It is by no means a simple problem to devise a satisfactory method 
of grading planks and scanthngs so as to bring out accurately the dif- 
ference in the results of seasoning by vaiious methods. The system 
of grading timber commercially for ordinary defects is entirely inade- 
quate, inasmuch as it does not take into consideration many of the 
defects that are of the greatest importance in comparing methods of 
seasoning. Obviously there are two general methods that may be 
followed; one is to determine the extent of the defects, the other 
is to determine the amount of sound material between the defects. 
At first thought it may appear that either method can be applied 
quite easily and that the results for the other can be quickly deduced. 
However such is not the case. Let us assume the case of a piece of 
timber which is spht, surface cracked, and mouldy on the surface to a 
given extent, i.e., to what we wall call arbitrarily the second degree. 
From the standpoint of a comparison of seasoning methods it makes- 
little difference whether these three defects overlap each other in one 
portion of the piece or whether they are entirely separate from one 
another and spread over the entire surface. From the standpoint 
of grading based on a certain percentage of sound material it makes 
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