414 



that the water gradually dried out from within the cells, but, 

 so long as there was any free water at all within the cells, the 

 walls remained saturated and no change consequently took 

 place in the dimensions of the block. The stage shown by the 

 curves of fig. 3 where the insignis blocks show no contraction 

 at all as they dry out from about 140 to about 50 per cent, 

 of moisture represents the phase therefore when the free water 

 is drying out from within the cells, but the cell walls are still 



O 



20 



PERCENTAGE OF. MOISTURE ON DRV WOOD. 



180 



40 



6C 



80 100 120 140 



160 



Fig. 4. 



Showing expansion with moisture of Pinvs maritima. 



A, sapwood parallel to rings. B, sapwood perpendicular to 

 rings. C, heartwood. 



saturated. Beyond that, when the cells have lost all their 

 free water, moisture is then given out by the cell walls and 

 contraction begins to take place, this contraction being much 

 more marked in the direction parallel to the rings than in the 

 radial direction. 



The blocks from which tlie curves of fig. 3 were drawn 

 were cut from near the centre of the tree and contained a 



