ANIMAL MECHANICS. 



of their intrinsic value, and partly for the purpose of compa- 

 rison with my own. 



It will be observed that their measurements of the cross 

 sections of these muscles are smaller than those given by me, 

 and would give, therefore, a larger value for the coefficient K. 



Measurements of Donders and Mansfelt. 

 Cross Sections of Biceps humeri and Brachiasus. 



Millims. Sq. in. 



i. Biceps humeri (long head), . . . 530 0.821 



,, (short head), . . . 452 0.701 



2 Brachiceus, 614 °-952 



1596 2.474 



Example, No. 2. — Flexors of the Leg. In order to measure 

 the force of the muscles flexing the leg, I placed the observer 

 lying upon his face upon a table, with the legs extended over 

 its edge, and having fastened down the thighs, I observed the 

 maximum weights suspended from the heel that could be 

 conveniently lifted, and found that 34 lbs. was the limit ; to 

 this must be added 3 lbs. for the weight of the leg, supposed 

 suspended at the heel, which was measured as 16 J inches 

 from the axis of rotation of the knee-joint. The perpendicu- 

 lars let fall upon the directions of the several muscles flexing 



the leg were then measured : — 



9. Distance from origin of brachiaeus to axis of elbow, . (183-31) (190-37) 



10. Length of radius, 235 238 



11. Length of humerus, 342 • 336 



12. Section of long head (b iceps), . . . 530sq.rn.rn. 



13. Section of short head, . „ 452 ,, 



14. Section of brachiceus, 614 ,, 



Cross section of an elementary bundle 



= -— sq. m. m. 

 500 



Total number of elementary bundles in the cross section of the flexors of forearm 

 = 798,000. 

 F 



