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Forestry Clubs for Young People

B. Frank HeintzlemanHarold Scofield BettsHarry Bruce WalkerHarry Lawrence WilsonMarie Foote HeisleyMary Aloysius AgnewUnited States. Bureau of Biological SurveyUnited States. Food and Drug AdministrationWilliam White

其他書名	Suggestions for Leaders of Forestry Clubs Formed in Connection with the Work of 4-H Clubs, Boy Scouts, Schools and Other Organizations
出版	U.S. Department of Agriculture, 1928
URL	http://books.google.com.hk/books?id=b3c9O9OxIn8C&hl=&source=gbs_api
EBook	FULL_PUBLIC_DOMAIN

註釋Tests to determine the mechanical properties of wood, such as bending tests, compression tests, shearing tests, etc., to be strictly comparable must be made on straight-grained pieces free from defects, such as knots, shakes, etc., and in the same condition of seasoning. It would manifestly be misleading to compare the strength of oak containing defects with clear hemlock or the strength of green ash with dry birch.