Part V.] Sweet: On Air Seasoning of Indian Timbers. 13 
{ if ) .Water Seasoning. 
The theory underlying the practice of seasoning by immersion in 
water is that, while there can be no drying while the wood is under 
water, the constituents of the sap — the gums, tannins, and albumi- 
nous materials — are either subject to a slow chemical change or 
gradually leached out of the cells and are replaced by fresh water so 
that the subsequent dr\ing may be carried out more quickly and with 
less loss due to cracking, splitting, etc. It is a fact that the origi- 
nal sap of the wood is much more difficult to extract during seasoning 
than ordinary water. For example, a piece of thoroughly seasoned 
wood, if soaked in water until it is entirely saturated, redries much 
more quickly and easily than when ft. was- originally seasoned. But, 
when we consider the structure of wood and the anatomical obstruc- 
tions to the ready flow of moisture through the cells, we come to 
appreciate fully how slowly the leaching process must proceed. 
Moisture in wood can penetrate but very slowly from cell to cell, 
usually by transfusion through membraneous structures, so that any- 
thing like a rapid replacement of sap by fresh water is impossible. 
The beneficial effects of soaking in water so far as cracking and 
splitting are concerned can be noticed, if at all, only after very 
long periods of time — periods, which under normal circumstances 
are entirely impracticable. It is said that Japanese craftsmen 
season some of their cabinet woods by immersing the pieces in freely 
moving water for several years. It is certain that soaking for a few 
months has no advantages, especially in the case of logs or large 
pieces. 
The beneficial effects of the leaching process are more quickly 
realized in the case of converted material, but the increased diffi- 
culty of handling the timber under these circumstances makes the 
practice unfeasible under ordinary conditions. There are indications 
that planks and scantlings of the soft woods, such as Bombax 
malabaricum, which are especially liable to severe staining and dis- 
colouration upon exposure to the air, are benefited by immersion in 
running water. In this case it is not unlikely that the leaching effect 
IS sufficient to cleanse the surface of the pieces and wash out the 
constituents of the sap near the surface so that the fimgus germs do 
not get a firm foothold on the wood before the timber is dry. 
Analysis of the results of these experiments show that, taking the 
average of all species, surface cracking was 31 per cent, greater by 
w'ater seasoning than by green conversion. Splitting was practically 
the same in both cases. It w'as noted further that the surface of 
pieces so immersed took on a dark, weather-stained appearance, and 
the grain was raised appreciably which, while doing no real damage 
to the wood, gave a suspicious appearance which in certain cases 
w'ould affect the sale value. 
Unless the water is clean, dirt and grit are embedded in the sur- 
face fibres so that machine knives and tools are quickly dulled when 
the wood is worked. 
[ 159 0 
