16 



H. T. BOVEY ON THE STEENGTH OF 



at A, under an eftect chiefly due to bending. The ehiniping, again, introduced a com- 

 pression, whicli rendered it impossible to obtain the true shearing-stress. 



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After a number of experiments, more satisfactory and reliable results were obtained 

 by preparing test-pieces similar to those submitted and shown by tigs. 4 and 5. The 

 bending action is by no means eliminated, and, generally speaking, it is practically impos- 

 sible to frame timber joints subjected to a pure shear only. The shearing strengths, which 

 are of importance, are the resistances along planes tangential and radial to the annular 

 rings. An examination of the test-pieces shows that the shears are almost invariably along 

 these planes. The special holders necessarily required tor the experiments, and for the 

 particular specimens in question, were designed in the lalmratory. 



With test-pieces of the form shown by tig. 5, the shearing istrengths along the tan- 

 gential and radial planes are obtained, while the shearing strength, which may be considered 

 as the resultant of the tangential and radial shears, is obtained with the test-pieces of the 

 form shown by fig. 4. 



T.ABLE OF Shearing Strengths. 



