COHERENCE. 



65 



TABLE OF SPECIFIC WEIGHTS OF 



78 



ss 



83 



75 



According to Mayr's observations, Weyinouth pinewood 

 wci^lis the same in Europe as in America, and P. lloth's 

 figures quoted in "The; \Yliitc 1'iiu'." ly \'. ^f 

 1S!)1I, concur. 



6. 



Coherence is the force thai keeps the constituents of wood 

 united ; it is measured by the resistance offered by wood to 

 shearing strains and to a separation of the cells, tissues, 

 or annual zones. Tetmajer states that the coherence of 

 wood may be measured by the amount of deformation 

 exhibited in testing its strength and by the force applied. 

 Its influence is here apparently greater than that of specific 

 weight, to which coherence is not proportional. Whenever 

 wood is utilized its coherence comes into play, but there are 

 no exact observations of this quality in woods of different 

 species. 



r.r. F 



