MECHANICAL PROPERTIES. TABLE 73. Conifers Grown in U. S. (Metric Units). 



97 



NOTE. The data above are extracted from tests on one hundred and twenty-six species of wood made at the Forest Products 

 Laboratory, Madison, Wisconsin. Bulletin 556 records results of tests on air-dry timber also, bat only data on green timber are shown, 

 as the latter are based on a larger number of tests and on tests which are not influenced by variations in moisture content. The 

 strength of dry material usually exceeds that of green material, but allowable working stresses in design should be bas.d on strengths 

 of green timber, inasmuch as the increase of strength due to drying is a variable, uncertain factor and likely to be offset by defects. 

 All test specimens were two inches square, by lengths as shown. 



COLUMN NOTES. 2, Locality where grown, see Tables 7 4 and 75; 3, Moisture includes all matter volatile at 100 C expressed 

 as per cent of ordinary weight; 6, Weight, air dry is for wood with 12 per cent moisture; for density, see metric unit tables 72 and 

 73; 6-10, 762 mm (30 in.) long specimen on 711.2 mm (28 in.) span, with load at center. 



SMITHSONIAN TABLES. 



