256 



FOREST TREES OF NORTH AMERICA. 



The following table gives the figures from which the table of relative values was computed, and includes all 

 species upon which complete tests have been made. 



The coefficient of elasticity is derived from the second deflection, the measurements being taken in millimeters 

 and the weight in kilograms. 



The ultimate transverse strength is the force, applied at the middle of the stick, required to break a stick 4 

 centimeters square and 1 meter between the supports. 



lu the compression tests the surface exposed to pressure was 4 centimeters square. To give the pressure 

 on a square centimeter these results must be divided by 16. 



The indentation to 1.27 millimeters, or the fifth in the series, is the one selected for comparison. 



TABLE OF AVERAGES. 



