Part V.] Sweet: On Air Seasoning of Indian Timbers. 
49 
the atmospheric conditions have changed and the moisture content 
of the wood begins to go in the opposite direction. 
The rate of change in moisture content varies with the species and 
the dimensions into whicli the wood is cut. 
It may be pointed out here that the effectiveness of an adequate 
covering, such as paint or A^arnish, in preventing the swelling and 
shrinkage of Avooden parts depends only upon the retarding of the 
rate of change, so that the part, under normal circumstances, does not 
come into complete equilibrium with either extreme of humidity. 
From the above explanation it aatII be noted that the moistm’e 
content in any locality even of seasoned Avood is subject to continual 
variation, and that the amount of the variation is dependent upon the 
climatic conditions, the species, and the dimensions into which the 
wood is cut. 
The marked seasonal fluctuations in the atmospheric moisture 
conditions make it impossible with our present data to give an accurate 
figure to represent the moisture content of air-seasoned timber for 
any region of India. EA'^en after further investigation and when the 
data are complete it may be necessary to give figures for different 
species and thicknesses. 
With these factors in mind we may turn to the data available from 
the tests made in the different Divisions as summarised in Appendix I. 
(i) Gonda Division, United Provinces. 
The data available concerning the moisture content of seasoned 
wood in this Division are based upon 63 tests of 16 species, including 
both hard and soft woods. The determinations were made early in 
April, 1921 at which time the moisture content of the thoroughly air- 
seasoned pieces Avas pi'obably, somewhat below the mean of wet season 
and dry season conditions. Basing the calculations on the pieces of 
each species which there is every reason to believe were absolutely 
air-seasoned, i.e., upon 1" boards converted from green logs and kept 
in open stacks for 25 months, the average moisture content Avas 8'3 
per cent. The variation in individual tests Avas from 7 0 per cent. — 
9‘6 per cent. AA’hich is a perfectly normal A'ariation in thoroughly 
seasoned pieces even of the same species. 
Using 8'3 (+ 1‘5) per cent, as the moisture content in April of 
thoroughly air-seasoned boards 1" thick it will be noted in examining 
the figures for this Division in Appendix I, that each of the methods as 
summarized below has produced thoroughly seasoned wood at least 
in 1" boards. 
(1) 16 — 20 months in log after felling followed by conversion 
and stacking for 8 months. 
(2) Conversion immediately after felling, and stacking for 21 — 
27 months. 
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