92 TIMBER AND SOME OF ITS DISEASES. [CHAP. 



the amount of water they displaced. A discussion as 

 to the sources of error leads to the conclusion that they 

 do not amount to more than about 0*5 per cent, on the 

 average. The pieces of wood were then dried for 

 some weeks. Some interesting observations were 

 made, confirming the conclusion that so-called air- 

 dry wood gives various weights according to the 

 condition of the atmosphere, and therefore of little or 

 no scientific value. 



The drying was then completed in a hot-chamber 

 at 105 iioC, and the dry weight registered: the 

 loss in weight of course registered the amount of water 

 contained in the wood. 



The next thing was to obtain the volume in the 

 dry state, in order to estimate the shrinkage ; this was 

 done, as before, by displacement, several careful 

 precautions having to be taken. 



So far, the following data were to hand : 



1. The specific weight (fresh) 



Absolute weight (fresh) 

 Volume (fresh) 



2. The specific weight (dry) 



Absolute weight (dry) 

 Volume (dry) 



3. The shrinkage 



Volume (fresh) - volume (dry) 

 Volume (fresh) 



