ANIMAL MECHANICS. 



49 



minutes, or — knots per hour ; hence, by the rule already laid 

 7 



down, the resistance per square foot of augmented surface is 



/6o> i 625 36 625,, 



— x x — = — x -~ lb. av. 



\7/ 100 644 49 644 



and finally, the total resistance is 



1 1 4. 1 1 x — x ^5 = 8i.q6 lbs. 

 49 ^44 



This resistance is overcome through the space of one knot 

 (1000 fathoms) in seven minutes ; and therefore 



The Total Work done = 81,36 X 6 ° 0Q = 218 ft. tons. 



2240 



The work done per man is 27.25 ft. tons in seven minutes, 

 or nearly 4 ft. tons each minute. 



A good idea may be formed of the rate in which the mus- 

 cles give out work in a boat-race, from comparing this work 

 with the average daily work of a labourer. At many kinds 

 of labour there are 400 ft. tons of work accomplished in ten 

 hours. The oarsman therefore performs, in one minute, the 

 hundredth part of his day's labour ; and, if he could continue to 

 work at the same rate, he would finish his day's task in l h . 40 m ., 

 instead of the customary 10 hours. 



The work done, therefore, in rowing one knot in seven 

 minutes, is, while it lasts, performed at a rate equal to six 

 limes that of a hard-worked labourer. 



The rate of work in this case is four tons per minute ; and 

 if we assume (p. 45) 575 oz. av. as the weight ofmuscles em- 

 ployed, we find the rate per ounce per minute to be 



81. 1.6 x 6000 „ 



= 15.169 it. lbs. per oz. per minute. 



8x7x575 



