ANIMAL MECHANICS. 377 



It will be unnecessary to investigate the biquadratic (92), 

 for the constant 20 = 90 0 gives usm = i, and therefore A = o, 

 is a root of the equation, as may be seen on inspection. 



To determine the points / and I' 9 we have 



p 2 = a 2 + a' 2 + 4c 2 , 



pf = ( a + a) 2 + (a' + a') 2 + 4c 2 , 



from which we obtain 



Pi 2 ~ p 2 = 2aa + 2&V + a 2 + a' 2 ; 



or, introducing the numerical values, 



5.22 a + 8.80 a 7 - 44 39 = o» 

 a ; = - 0.6 a + 5.04. 



Introducing this expression into the first equation, we find 

 1.36 a 2 - 6.05 a - 9.12 = o, 



and finally, 



+ 5.64 f _ ( + 1 66 



- r-i5 a ~ (+ 5-73 



An inspection of the bones shows that the last pair of 

 \alues are those to be employed, and thus we find 



a = - 1. 15 in. a' = + 5.73 in. 



ai = + 1.46 „ a x ' = + 10.13 „ 



- =-0.144 — = + 0.716 

 P P 



— = + 0.126 — = + 0.808 

 Pi Pi 



= -0.018 



