ANIMAL MECHANICS. 



53 



tion near the Pest Fields of St. Giles, at a little distance from 

 Tyburn Road. The body was carried by night, without much 

 difficulty, on Crambe's back, who found it easy (being both 

 young and lusty) to travel along the level road, carrying on 

 his legs the double weight, of the malefactor, and of his proper 

 self. As soon, however, as he commenced to ascend the 

 staircase, the wonderfully increased exertion (20 to 25 times 

 as great as before) began to tell upon Crambe, and, as the 

 accurate narrator records, upon the corpse also ; in conse- 

 quence of which Crambe dropped his burden in disgust and 

 fright, and allowed it to roll down the staircase, while he him- 

 self ascended breathless into the upper room, where Martin, 

 scalpel in hand, eagerly awaited the arrival of his expected 

 subject.* 



Next to the exertion of lifting his own weight, the sim- 

 plest mode in which the force of man can be employed is in 

 transporting the weight of his body, loaded or unloaded, along 

 a horizontal road ; and the work done in horizontal transport 

 of loads may be readily shown to be about ^V tn P art °f tne 

 work done in lifting the same loads vertically through heights 

 equal to the horizontal distances. 



In order to obtain the proportion between the work done 

 in the horizontal and in the vertical transport of weights, we 

 must examine the mechanism of simple walking. 



In the act of walking, it is found that the leg which rests 

 upon the ground supports the centre of gravity, which is first 

 lifted by the thrust of the other leg against the ground, and 

 afterwards falls forward, while the suspended leg swings as a 

 pendulum, and becomes in its turn the support of the centre 



* It is true that Mr. Pope gives a different account of the cause of this cele- 

 brated disaster, and one which acquits Crambe of the charge of having proved 

 unable to carry the malefactor up a flight of stairs ; but I feel no hesitation in 

 asserting that my own explanation of the misadventure is preferable. 



