TIMBER AND TIMBER TREES. 



between this volume and that of the hygroscopically 

 absorbed water. Numerous experiments have shown 

 that this imbibed water ranges from 50 to go per cent, 

 of the volume of the solid wood-substance, according to 

 the species and some other circumstances. In the case 

 selected we will take it at 50 per cent. — i.e. half the 

 volunie of the solid wood-substance. 



Returning to our example, then, we find that our 

 piece of fresh wood, the volume of which was 100 

 cubic centimeters, and the weight 85 grams, contained 

 50 grams of water altogether, and 35 grams of solid 

 substance. 



The cubic contents of this solid substance measured 

 22-43 cubic centimeters, and would contain half that 

 volume — i.e. 11-215 cubic centimeters — of imbibed 

 water, making 33-645 cubic centimeters in all. 



The remainder of the cubic contents refers to the 

 cavities : it would be 66-355 cubic centimeters. 



Now there were 50 cubic centimeters of water 

 altogether in our 100 cubic centimeters of fresh wood, 

 and we have accounted for the distribution of 11-215 

 cubic centimeters of its water. Obviously, the diffe- 

 rence, namely 38-785 cubic centimeters of water, was 

 contained in the cavities, and as these measured 66-355 

 cubic centimeters, the remainder — i.e. 27-57 cubic centi- 

 meters—was gaseous matter, and as a matter of fact we 

 know that it was chiefly air-bubbles. 



This will suffice to show you how very complex a 

 structure our piece of wood is, and to convince you that 

 the physicist is in error if he regards it merely as a 

 " porous body," for it is obviously much more than what 

 is implied by that term. 



As we shall see presently, the piece of wood consists 

 essentially of bundles of tubes, and, consequently, it 



