THE ACACIA 133 



plant ; but the quality of its timber undoubtedly 

 varies according to the character of the soil in which 

 it is grown. It may reach a height of seventy or 

 eighty feet, with a diameter of two, three, or, in 

 Kentucky, as much as four feet ; and even in the 

 neighbourhood of London it has been known to 

 forty feet within ten years, sometimes making shoots 

 reach eight or ten feet long in a single season. 



The wood of the best varieties, when well grown, 

 is hard, strong, and durable, takes a good polish, and 

 is prettily veined with brown. The sapwood is very 

 narrow, comprising generally only five annual rings, 

 and of a yellowish white colour. The pith-rays are 

 very fine and far less distinct to the naked eye or. 

 under a low-power lens than they appear in the 

 photomicrograph. The vessels in the spring-wood 

 are very large and form a broad pore-circle, but, as 

 all of them are filled up with ingrowths, or " tyloses," 

 as they are called, of thin-walled cells, they appear 

 as clear yellow spots on the dark wood. The small 

 vessels in the autumn-w T ood are crowded together in 

 groups of as many as ten between two pith-rays, and 

 these groups being side by side produce " peripheral 

 lines," or pore-zones, parallel to the margins of the 

 rings. 



Besides its use in shipbuilding and for agricultural 

 purposes, the wood is emplo} 7 ed in America for the sills 

 of doors and windows, for cabinet-work, and in the 

 making of toys. When quite dry it weighs forty- 

 eight pounds per cubic foot, being, in fact, heavier, 

 harder, stronger, tougher, more rigid, and more elastic 

 than English Oak. Speaking absolutely, however, it 



