THE WOODS OF THE UNITED STATES. 



259 



TABLE OF AVERAGES Continued. 



The following table illustrates the relation between the specific gravity and the transverse strength of the 

 wood of species upon which a sufficient number of tests has been made to render such a comparison valuable. The 

 determinations of the specific gravity and transverse strength were, in every case, made upon the same specimen, 

 at the same time. The table is arranged according to the specific gravity of the specimens. 



It will be noticed that the strength of the different specimens closely but not invariably follows their specific 

 gravity. An examination of Table III will show, however, that in nearly every case where any wide difference 

 occurs it is due to imperfections in the stick disproportionately affecting its strength. Moreover, in the case of 

 species where the specific gravity and strength of different specimens are nearly identical, their order of arrangement 

 becomes largely accidental. A slight difference in the time occupied in the strength tests, or slight variations in 

 the direction of the grain of the wood, may considerably affect the sequence in such a table : 



TABLE ILLUSTRATING THE RELATION BETWEEN TRANSVERSE STRENGTH AND SPECIFIC GRAVITY IN THE WOOD 



OF CERTAIN SPECIES. 



