ANIMAL MECHANICS. 337 

 Introducing this value into the equation, 



p 2 = a B + a' 2 - 2aa' cos 2(p + 4c 2 , 



we obtain 



0.602 a 2 + 0.888 a 2 - 4.356 = o ; (95) 



and, finally, remembering (94), we reach the following pairs 

 of real values for a and a : — 



|+ 2 05 in. (observed = 1.96 in.) 

 a ~ 3-53 » 



, ( + 4.51 in. (observed = 4.40 in.) 

 a = j 



(-0.025 »> 



From the preceding agreement of calculation and observation, 

 we may regard the true positions* of / and T as having been 

 accurately ascertained. 



We are now in a condition to determine the quantities, 

 X, X\ K, which occur in the coefficients of the equation of 

 condition (92) ; for 



K = sin 2 <p * 2 (™ 2 - 0 2 Q j ^ 



Using the measurements made in the freshly-dead muscle, 

 we obtain the following: — 



Llama — Adductor secundus (|3). 



a = + 2.05 in. a = + 4.51 in. 



a 3 = + 1.40 a \ = + 6.51 „ 



o 2 = + 0.75 a 2 = + 8.5 1 



a 3 = + 0.09 „ a' 3 = + 10.51 ,, 



* The second values of a and a', refer to the position of the bones, in which 

 they make together an angle of 20 reversed ; and they have no relation to the 

 present problem. 



Z 



mX = sin 6 S [ - ] ml' = sin <h 2 



