抄録
A study is made whether the moisture content and height in fibre direction of a wood specimen (cryptomeria) have effects on the velocity of suction during a short time after soaking by paying attention to the head loss of gas flow through the specimen.
As regards the moisture content, water is sucked faster in dry specimen than in normally moist one owing to rapid vapour-sorption of the former. But if the water content of a comparatively hydrophobic specimen amounts to about 24% in the atmosphere of about 960 relative humidity, it is shown that the suction velocity becomes greater than that of normally moist one on account of remarkable decrease in advancing contact angle between water and capillary wall. But, as to a specimen kept in saturated water vapour, the head loss of gas flow in its capillaries may be much greater than that in a normal specimen and the gas in some of the capillaries of the former is more or less trapped there by wet capillary walls, and therefore, the flow of gas which is in contact with rising water meniscus in the capillary is easily obstructed as the capillary walls become wet by water already risen freely in neighbouring capillaries.
Change in height of specimen, if the height is less than 10 cm, seems to have no effect on the suction velocity.
