Forest Mensuration 67 



The point at which a defect is located greatly influences its effect on 

 the grade of the lumber. 



The two faces, the two edges and the two ends of a board must be 

 parallel. In case of unevenness, the thinnest thickness, the narrowest 

 width and the shortest length are measured. 



Lumber is measured with the help of a lumber rule (Lufkin rule) which 

 yields for inch boards of given lengths and given width the correspond- 

 ing contents in feet b. m. 



In measuring the widths, fractions of an inch are neglected in rough 

 lumber. 



PARAGRAPH CI. 



INSPECTION RULES AND NOMENCLATURE. 



The lumber inspection prevailing in a given market is governed by 

 local custom or by agreement within the body of local associations of 

 lumbermen. 



The tendency of all inspection rules is directed toward a gradual lower- 

 ing of rigidity. 



The wholesaler's inspection is generally stiffer than that of the manu- 

 facturer. Diversity of rules is a sadly demoralizing element in lumber 

 circles. 



Lumber sawn for special purposes (e. g., wagon bolsters) must be in- 

 spected with a view to its adaptability for such special purpose. 



A. Hardwood. The grade of a board depends on 



1. Its width and length ; 



2. Its standard defects ; 



3. The percentage of clear stock contained therein ; 



4. The number of cuttings yielding such clear stock. 



The following table shows average specifications prevailing for the 

 various grades of hardwood lumber in the U. S. markets. 



The defects specified invariably indicate the coarsest stock admissible 

 in a given grade. 



