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 vemed 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-wood 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 employed 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 



