ANIMAL MECHANICS. 



175 



8. 1 5 inches in length. These measurements correspond with 

 the following mean cross sections : — 



Biceps, 1.067 sq. in. 



Brachials, . . . . 0.539 ,, 



The angular velocity with which the forearm turns on the 

 elbow joint is not proportional merely to the force of the 

 muscle, but to the product of that force into the distance from 

 the point of insertion to the axis of the elbow joint. I mea- 

 sured these distances carefully, for the purpose of obtaining 

 a comparison between the angular velocities produced by the 

 biceps and brachiceus muscles respectively. The following 

 Table contains the measurements and results ; and 1 have 

 added corresponding measurements taken from the arm of a 

 very fine Lioness. 



In the Lioness the biceps muscle weighed 6.70 oz., and had 

 a length of 8 inches ; and the brachiceus muscle weighed 

 2.60 oz., and had a length of 8.75 inches. 



Table XXVIII. — Angular Velocity of Forearm produced by 

 Biceps and Brachiceus Muscles. 





Biceps. 



Brachiceus. 



Ratio of An- 























gular Veloci- 













ties producet 







Distance of 





Distance of 



by Biceps and 





Cross Section. 



Insertion from 



Cross Section. Insertion from 



Brachiceus. 







Axis of Joint. 





Axis of Joint. 





Nylghau, . 



Sq. In. 



In. 



Sq. In. 



In. 





1.98 



1.02 



0.7 1 



2.26 



I.26 



Ass, . . . 



9.72 



I.24 



059 



2.00 



IO-2I 



Sambur, 



3.16 



1.72 



0.S6 



2.44 



2-59 



Lioness, 



1.38 



2.29 



0.49 



2.16 



3.00 



The total angular movement of the forearm produced by 

 each muscle will be proportional to the length of the muscle 



