464 SELLING LUMBER 



ally, some are much stronger than others. 



Owing to the confusion which frequently results in the 

 proper classifying of timbers into long leaf, short leaf, lobolly, 

 etc., a new rule has been devised and recently adopted by the 

 American Society for Testing Materials and known among the 

 trade as the "Density Rule" which classifies all Southern Pine 

 timbers, irrespective of botanical species, into two classes ; 

 namely "Dense Southern Yellow Pine" and "Sound Southern 

 Yellow Pine." 



Details and description of these designations will be found 

 in these pages. 



The Southern Pine Association recommends that all timbers 

 be branded. All manufacturers and dealers are urged to brand 

 their timbers in accordance with the grades and classifications 

 contained in this book. 



Southern Pine Association. 

 New Orleans, La., March 15, 1916. 



GENERAL TIMBER SPECIFICATIONS 



All timber except No. 1 Common must be free from defects 

 such as injurious ring or round shakes, and through shakes that 

 extend to the surface ; unsound and loose knots, and knots in 

 groups that will materially 'impair the strength. Seasoning 

 checks and discolored sap shall not be considered defects in 

 any grade. 



KNOTS 



(Adopted by the American Society for Testing Materials, 

 August 21, 1915.") 



Knots shall be classified as round and spike in form and for 

 quality as sound, encased, loose and unsound. 



A round knot is one which is oval or circular in form. 



A spike knot is one sawn in a lengthwise direction ; the mean 

 or average width shall be considered in measuring these knots. 



A sound knot is one which is solid across its face and which 

 is as hard as the wood surrounding it ; it may be either red or 

 black, and is so fixed by growth or position that it will retain its 

 place in the piece. 



An encased knot is one whose growth rings are not inter- 

 grown and homogeneous with the growth rings of the piece it 



