226 TIMBER AND TIMBER TREES. [ CHAP. 
even in plank, if exposed to a dry current of air, as under 
such circumstances it is very liable to split with fine deep 
shakes from the surface. 
Having this serious liability to rend in seasoning, 
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 time 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 ina 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; 
FIG. 27. there is also another, and rather 
peculiar defect, consisting of seve- 
ral complete consecutive circles of the annual layers being 
softer and more spongy than the natural or healthy wood 
(Fig. 27). They are darker in colour, and contain much 
moisture, and are, as pointed out in Chapter VI., p. 34, 
considered detrimental to the quality, strength, and 
durability, and consequently, to the value of the tree. 
The surveyor should, therefore, 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 
