DEFECTS IN TIMBER AND GENERAL NOTES 295 



it very often is not, its condition may become worse on the 

 voyage, it sweats and " blueing " occurs, and few would take 

 " blue" deals except for the commonest purposes. 



It is not easy to detect sap in certain conditions of SOUK; 

 of the wbitewoods, as the colour of all the timber is much 

 the same, although the sap has generally a dirtier tinge ; 

 looking at a pile of round Swedish or Russian redwood 

 logs we see the ring of lighter coloured sap about an inch 

 thick distinctly marked from the reddish tinged heartwood 

 (Fig. 37) ; but when the timber is squared and a good deal 

 of the sap is cut off in the process the difficulty is increased, 

 particularly so in the case of 

 whitewood, as the sap is then only 

 found at the edges and partly on 

 the sides. Sap is almost invariably 

 found on the edges even if absent 

 from the sides. 



Sapwood is not so objection- 

 able where the timber has to be 

 creosoted, as any one looking at a 

 pile of telegraph poles (Fig. 37) 

 will notice the complete ring of 



sapwood encircling the log, yet the long life of telegraph 

 poles proves this not to be deleterious. 1 



The presence of sap in commercial timber is due to the 

 same cause as wany edges, viz., the desire of the timber con- 

 verter to get as much timber as possible out of the tree. 



" Wany timber " is the expression used for logs the edges 

 of which are not sharp. Some timber is imported " wany," 

 but much of the " square " timber has wanes on some parts 



1 As a mle creosote does not enter much into the heartwood, and 

 the presence of a ring of sapwood in timber to be creosoted ensures its 

 perfect preservation. In the case of street paving, however, it is possible 

 that the snppy portion might not wear so well as the rest. 



FlO. 51. 



