DWARFS AND GIANTS. 769 



the same absolute height, each one performs a work precisely propor- 

 tional to its mass ; and, when a man leaps over an obstacle sixty centi- 

 metres from the ground, he accomplishes, other conditions being the 

 same, a task as considerable again as that of the flea or the grasshop- 

 per, which can not spring much above thirty centimetres. 



A few figures will make the matter plain. Take a grasshopper 

 weighing six decigrammes (nine grains), and a man weighing sixty kilo- 

 grammes (one hundred and fifty pounds). The man is equivalent in 

 weight to a hundred thousand grasshoppers. But a hundred thousand 

 grasshoppers grouped into a single mass could only raise that mass 

 thirty centimetres, while the man can lift his own mass sixty centi- 

 metres. All the advantage, then, is on the side of the man. Here is 

 a wide variance from the strength which has been exacted of the horse 

 to make him a rival of the flea. 



The basis of the comparison was vicious. The height or volume 

 of the agent who handles a weight has nothing to do with the estima- 

 tion of the labor. A sack of meal is no heavier on the shoulders of a 

 man than on the loins of a horse. The labor and the effort have been 

 confounded. The labor is a defined and absolute quantity ; the effort 

 a vague and variable sensation. 



The deductions respecting speed have no better foundation. The 

 ant, as a moving body, is a little mass of matter on which a determined 

 force impresses a speed of two and a half metres a minute. To impress 

 the same speed on a mass of fifteen millions of ants which I take to 

 represent the volume of a man would require a force fifteen millions 

 greater. This force is developed by a man going two and a half metres 

 a minute, while in the same space of time he can easily accomplish 

 a hundred metres and more. In this case, then, if we take notice of 

 any one of the data, the man manifests a strength forty times greater 

 in proportion than that of the ant. This is a very different result from 

 the one arrived at by the other method. Other data, however, com 

 in to complicate the comparison and considerably modify the result. 



A little closer study of the phenomena of walking will show us that 

 it absorbs a considerable quantity of force that does not appear in 

 speed. It is not simply a uniform transportation of the body along 

 an horizontal line ; but at each step the body is raised, and falls again. 

 The incessant repetition of the lifting is a great cause of fatigue. 

 Hence, walking on an uneven road tires us greatly. In the best paths, 

 the differences of level which have to be overcome correspond with a 

 notable quantity of force lost from speed. The ant, however, being a 

 creeping thing, and supported on six feet, has to raise only a very 

 small part of its weight at each step, and is therefore more advanta- 

 geously formed than the man, who, having only two feet, gives to his 

 whole body a double oscillation sidewise, and up and down. On the 

 other hand, the ant feels even the slightest inequalities of the ground. 

 When it goes over the space that represents a man's step, and requires 

 vol. xxii. 49 



