172 



ANIMAL MECHANICS. 



the Ass are equivalent, are totally different from the long thin 

 brachiceus muscles, associated with them in the flexion of the 

 forearm. 



If we assume the specific gravity of muscle to be 1.050, 

 the weight of a cubic inch of muscle, expressed in avoirdu- 

 pois ounces, will be — 



Cubic inch of muscle = T -°5 Q x 2 5 2 5 x *6 _ Q Qz< 



7000 



In the Nylghau, the weight of the biceps muscle is 3.44 oz., 

 and its length 6 inches ; hence, its cross section, w, is 

 3.44 



w = — — = 0.046 sq. in. 



6 x 0.606 ^ 



but 



W = 2.O9 W = I.977 sq. in. 1 Equivalent Prismatic biceps of 

 L = 2.85 in. J Nylghau. 



The weight of the brachiceus is 3.43 oz., and its length is 8 

 inches ; hence its cross section is — 



w - ■ — - — ^—7 = 0.707 sq. m. f 



8 x 0.606 V Brachiceus of Nj T l^hau. 



/= 8 in. ) 



These two muscles are of nearly equal weight, and therefore 

 contain nearly equal amounts of inherent work, and we can 

 easily verify the statement already made (26), that they give 

 out equal quantities of work, although one has its fibres pris- 

 matic and the other penniform. 



"Work done by biceps (penniform) 



= 1.977 x 2.85 = 5.63. 

 Work done by brachiceus (prismatic) 



= 0.707 x 8 = 5.65. 



In the Ass, the weight of the Biceps is 6.83 oz., and its 

 length is 6.6 inches ; hence its cross section, w, is 



6 - 8 3 



6.6 x 0.606 



1. 71 sq. in. 



