370 



FORESTRY INVESTIGATIONS U. S. DEPARTMENT OF AGRICULTURE. 



From these tests the following table of averages is derived, together with tig. 97: 



Artraye uf U'sts for mafimum uniformity. 



It will ho observed that green cypress excelled in its uniformity; that green lolilolly proves not more uniform 

 than dry white and longleaf pine; that wood of the conifers far excel even the tnliptree (poplar) with its uniform 

 grain and texture; and that oak, as might be expected, is the least uniform. It will also be noticed that even in 

 one and the same short scantling ((i to 10 feet) of select quarter-cawed longleaf pine differences of 10 per cent may 

 occur, anil that in all others these differences were even greater. 



Incidentally in this and the following experiment a small number of the blocks were thoroughly oven-dried 

 (to about 2 per rent moisture), and it was found that the strength of both cypress and loblolly was increased by 

 about 150 per cent during drying, so that wood at '2 per cent is about two and one-half times as strong as perfectly 

 green or soaked material; and also that drying from 8 to 10 per cent to the lowest attainable moisture condition 

 ( 1 to 2 per cent) still adds about 25 per cent to the strength of the wood. 



In the following diagram and table a part of the results are presented in detail : 



/O.OOO 

 9.OOO 



8000 



7OOO 

 6.OOO 



4000 



3.000 



Z.OOO 



x 



Or 



3 57 9 // /3 /S /7 /9 ~ 2/ 23 25 



Fio. 97. Strength of contiguous blocks, showing maximum uniformity of select quarter-sawed material in compression endwise. 



