284 



STRENGTH OF MATERIALS 



might be expected, since the larger commercial pieces contain knots 

 and other defects not found in the selected test pieces. It has been 

 found also that the place and conditions of growth, tune of felling, 

 method and time of seasoning, and many other factors have each 

 some effect upon the strength of timber. Since the weight of timber 

 is an indication of its strength, some idea of the relative strength 

 of the more common species may be obtained by referring to the 

 table given below.* 



WEKiHT OF KILN-DRIKD WOOD < >F DIFFERENT 8PB< 11^ 



238. Compression tests. Compression tests are made on short blocks 

 and long columns. Km the short-block test the piece is placed in an 

 ordinary testing nmrhinc l..-tur,-n tli. nmviim IUM! and the plat: 



Bureau of Forestry. Itnllffin A r ". 7 />. "Timber." 



