660 UTILIZATION OF BARK AND ITS CONSTITUENTS. 



cut into saw-mill butts, are peeled with the harking-iron or the 

 axe, so as, if possible, whenever the log is not too thick, to 

 remove the bark in one piece. The men, however, prefer 

 peeling firewood blocks a meter long, to peeling heavy logs 

 and butts. The bark is spread out on poles or placed on an 

 incline to dry, or arranged as in Fig. 358, the roof-like 

 structure thus formed being covered with numerous other 

 pieces of bark, and thus secured against the rain. In setting- 

 out the pieces of bark to dry, they are bent outwards so as 

 almost to break along their middle line, in order to prevent 

 them from rolling up, otherwise they would not dry thoroughly. 

 As in all trees, the bark of young spruce contains more 



Fig. 358. Drying spruce-bark. 



tannic acid tl:an that from old trees; and the bark of trees 

 grown wide apart, or in the open, and of trees exposed to the 

 south or along the borders of a forest, is richer in tannic acid 

 than those under opposite conditions. 



In most countries dried spruce-bark is stacked like ordinary 

 firewood and sold by the stack ; a stacked cubic meter (35 cubic 

 feet) contains 0'3 cubic meters (10 cubic feet) of solid bark. 

 Well-stacked, smooth, middle-aged spruce-bark, when air- 

 dried, weighs from 150 to 175 kilos per stacked cubic meter 

 (4J to 5 cwt. per load of 50 cubic feet). It is sold also by the 

 tree, by the hundred rolls, by the volume of the barked wood, 

 or by the drying stack (Fig. 358) containing 12 to 15 pieces 

 of bark. Selling by the amount of peeled wood is the simplest 

 method, provided sufficiently accurate ratios between the wood 

 and bark have been ascertained ; for wood 80 to 100 years old, 



