ANIMAL MECHANICS, 



479 



back to the heart by the arterial blood, because the heart 

 never tires ; hence 



Coefficient of Refreshment of human heart 0.2377 ft- lb, 



Next to the action of the heart, the best example we have 

 of muscles continuing to act for a long time without fatigue, 

 is the case of the muscles used in the act of walking. Let us 

 examine the Coefficient of Refreshment for these muscles. A 

 man walking at the most convenient pace for a long day's 

 work walks at the rate of one mile per 17 \ minutes. Hence 

 the distance travelled in one second will be 



j 5280 



17.5 x ; 6q* 



The work done (p. 54) will be, at this pace, part 

 of the weight, which maybe taken at 150 lbs., lifted through 

 the above space. Hence, the work done in one second by 

 the walking muscles, is 



5280 x ico c u 



— ■ ~z ' — - 32.752 ft. lbs, 



17.5 x 00 x 23.03 ^ 



The muscles more or less employed in the act of walking 

 are those of the hip, knee, and ankle-joints. Taking the 

 weights of these muscles from the tables (pp. 401, 404), wo 

 obtain for each side 124.27 oz. This weight doubled, or 

 248.54 oz., is the total weight of muscles employed in doing 

 the work just calculated. Hence we obtain 



Coefficient of Refreshment 32.752 f „ 



of walking muscles s -0,1318 tt, lb, 



The following experiments were undertaken in order to 

 obtain additional data to determine the Coefficient of Refresh- 

 ment. Dr. Macalister, holding 10 lbs. in each hand, at a 



