52 



ANIMAL MECHANICS. 



into the upper cage, and descending by his weight, lifts the 

 full barrow through forty feet, to the higher stage, where it is 

 at once removed by a second assistant. The labourer then 

 leaves the cage in which he has descended, and returns to the 

 higher stage, by mounting a ladder ; and again steps into the 

 upper cage, which is now ready to commence the descent 

 afresh. It has been found, by repeated trials, that a labourer, 

 aided by two assistants, to bring and remove the loaded and 

 empty barrows, is able to work for eight hours a day, during 

 which he lifts his own weight (70 kilos.) through a height of 

 13 metres, 310 times. 



From these data we find 



Work done in one day = ^° X ~ T ° = 910 ft. tons. 



Converting this result, as before, into work done, expressed 

 in ft. lbs. per ounce of muscle, per minute, we obtain 



Rate of work, per ounce, per \ 



„ I 9 IQ x 22 4° c iv 



minute, of muscles em- > = x 8 x .^j~t ~ 7*3^9 



ployed in climbing, . . . ' 



The example just given may be confirmed by the follow- 

 ing : — A friend has informed me that he performed the ascent 

 of Monte Rosa, from Zermatt, 9000ft., in nine hours, his weight 

 being 14 stone. Here we have 



Rate of work, per ounce, per \ 



p i I 14 x 14 x 0000 n „ 



minute, 01 muscles era- = 7 = c.ooQit.lbs. 



. . ) 9 x 60 x 575 D 3 



ployed in climbing, . . . ' 



Example, No. 3. — It is recorded in the Memoirs of the in- 

 comparable Martinus Scriblerus, how, in his eager pursuit 

 of knowledge, he met with an extraordinary misadventure, 

 through the ignorance of his assistant, Crambe. Having se- 

 cured the body of a malefactor, he hired a room for its dissec- 



