SPECIES OF WOODS. 



131 



Physical Qualities: Heavy (6th in 

 this list); 47 Ibs. per cu. ft.; sp. gr., 

 0.7617; very strong (4th in this list); 

 very elastic (6th in this list) ; hard 

 (llth in this list) ; shrinkage, 6 per cent, 

 warps, little; not durable if exposed; 

 rather hard to work; splits hard, tough. 



Common Uses: Dowel pins, wooden 

 ware, boats and ships. 



Remarks: The birches are not usu- 

 ally distinguished from one another in 

 the market. 



Radial Section, 

 life size. 



Cross-section, 

 magnified 37^2 diameters. 



Tangential Section, 

 life size. 



