IS BULLETIN 67, U. S. DEPAETMENT OF AGEICULTURE. 



per cent greater and a crushing strength 18 per cent greater than the 

 fire-killed lodgepole pine. It might seem at first sight that these 

 dififerences were due to deterioration on the part of the fire-killed 

 material, but an analysis of the values in regard to weight and a 

 comparison with values obtained from other tests on lodgepole pine 

 indicate that deterioration is not the probable cause of the difference. 

 It has been proved conclusively that in any species the strength of the 

 clear wood varies directly .with its dry weight. 



