178 



TIMBER AND TIMBER TREES. 



[chap. 



the logs should never be left a week exposed to the 

 influence of drying winds without some kind of protection, 

 for even less than that tinae is often sufficient to bring 

 about an amount of deterioration which will greatly 

 affect their value. Therefore, to preserve this timber 

 for future use, it should be treated in the same manner 

 as the English common Elm, namely, by immersing 

 it in water ; or, if this cannot be done, conveniently, 

 it should be cut into planks of thicknesses which would 

 be available for further conversion if required, taking 

 care to store it in a dry, cool 

 place, under cover, but quite free 

 from draught. 



The star-shake, in a mild 

 form, is rather common to this 

 description of timber, but does 

 not usually extend to more than 

 2 or 3 inches from the pith ; 

 there is also another, and rather 

 peculiar defect, consisting of 

 several complete consecutive 

 circles of the annual layers being softer and more spongy 

 than the natural or healthy wood (Fig. 24). They are 

 darker in colour, and contain much moisture, and are, as 

 pointed out in Chapter V., p. 63, considered detrimental 

 to the quality, strength, and durability, and consequently, 

 to the value of the tree. The surveyor should, there- 

 fore, in selecting this wood take only the logs with a 

 uniform whitish colour for his best work, and leave those 

 which are marked with the dark annular layers upon 

 the ends for inferior purposes. 



In all other respects the Canada Rock Elm is a safe 

 wood for the converter to deal with, the instances of 

 defects being found in opening it, arising either from 



FIG. 24. 



