LAWS OF BONE ARCHITECTURE 



207 



The successive sections of bone which will be studied- are of 

 such irregular shapes that the formulas of calculus can not be 

 employed directly for the computation of the horizontal shears. 

 For this reason graphical methods will be used which will give 

 an accuracy within 1 per cent of the absolute values. 



51. Computation of horizontal shearing stresses. To illustrate 

 the methods that have been employed for the determination of 

 the horizontal shearing forces, the computations in tabular form 



Fig. 11 Circle two inches in diameter, subdivided into strips ^o inch wide 

 for the purpose of computing the shear factors by which tlie average vertical 

 shear is multiplied, to give the value of the horizontal shearing stress at any 

 given point in a beam of circular cross section. See paragraph 51. 



are presented for a circular cross section 2 inches in diameter 

 (fig. 11, and table 2). Two axes at right angles are drawn 

 through the center of the circle in figure 11. Then a series of 

 lines is drawn parallel to axis A-A at intervals of ^ inch, and 

 a second series is drawn at right angles to A-A, thus dividing 

 the area above A-A into squares whose sides are ^ inch long. 

 The strips are numbered in order from the axis A-A, the first 

 being 1, and so on, as shown in column 1, table 2. In column 

 2 are given the areas of the successive strips. Column 3 gives 



