;o 



PLANT BIOLOGY 



(incorrectly called poplar) is employed for wagon bodies 

 and often for house finishing. It often resembles curly 

 maple. 



Beauty of grain and polish gives wood value for furni- 

 ture, pianos, and the like. Mahogany and white oak are 

 most beautiful, although red oak is also used. Oak logs 

 which are first quartered and then sawn radially expose the 

 beautiful silver grain (medullary rays). Fig. 86 shows one 



mode of quartering. 

 The log is quartered 

 on the lines a, a, b,b ; 

 then succeeding 

 boards are cut from 

 each quarter at i, 

 2, 3, etc. The nearer 

 the heart the better 

 the "grain " : why ? 

 Ordinary boards are 

 sawn tangentially, 

 as c, c. Curly pine, 

 curly walnut, and 

 bird's-eye maple are 

 woods that owe their 

 beauty of grain to wavy lines or buried knots. Merely a 

 stump of curly walnut is worth several hundred dollars. 

 Such wood is sliced very thin for veneering and glued 

 over other woods in making pianos and other pieces. If 

 the cause of wavy grain could be found out and such wood 

 grown at will, the discovery would be very useful. Maple is 

 much used for furniture. BircJi may be colored so as very 

 closely to represent mahogany, and it is useful for desks. 



Special Products of Trees. — Cork from the bark of the 

 cork oak in Spain, latex from the rubber and sap from the 



Fk;. 86. — The Making of Ordinary Boards, 

 and One Way of Making "Quartered" 

 Boards. 



