STRENGTH TESTS OP STRUCTURAL TIMBEES. 



£ZASricl/Mir 



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 3em M//vs£/f 

 rtsfi/ii. o— O r/f^AT^D (bo/l/mg process} 



g = Butts T ' Top* 



Fig. 6. — Effect of "boiling process" of preservative treatment on the strength and stiffness of Douglas-fir 

 stringers treated green, air seasoned and tested. 



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Fig. 7.— Effect of "steaming process" of preservative treatment on the strength and stiffness of Douglas-fir 

 stringers treated green and tested without seasoning. 



