— 
wet or green wood because the intermicellar layers of water a 
very thick a 
of the thickness of the layer, however, the thinner stratum of the 
liqui 
< 
nd the surface tension is we 
aker; with the fe 
dis held most tenaciously, and continued 
exposure to high temperature is necessary to 
expell all the water, if indeed this is at all 
possi 
When a body from which much of the in- 
body wh: make up. practical 
equen is action are matters 
daily illustration in woode: rniture, and 
ho s. other instance is afforded 
b well-known practice quarrymen of 
driving wooden wedges into holes drilled in 
the rock, then wetting the s which swell 
with such force as 10 Spit oe masses of rock. 
Another d by the welling 
of wetted acca: These bodies are analy 
very dry, and must absorb much water before 
traction of ee acids, ie other substances 
inside of the cells, and as might be expected 
Fig. 2. Apparatus for measuring expansive force of 
swelling seeds. B, bulb filled with water and connected 
and mer 
is imbedded i dis in» jar: ipp 
the free arm of tk has | d it 
a pressure of about 1.5 atmospheres. (F rom MacDou- 
are Practical Plant Physiology, by permission of Long- 
mans, Green & Co.) 
