THE ANIMAL MACHINE 



ingenious feat of all which our primitive ancestor accom- 

 plished was in learning to utilize the muscular energy 

 of other animals. Of course the example was always 

 before him in the observed activity of the animals on 

 every side. Nevertheless, it was doubtless long before 

 the idea suggested itself, and probably longer still before 

 it was put into practise, of utilizing this almost inex- 

 haustible natural supply of working energy. 



DOMESTICATED ANIMALS 



The first animal domesticated is believed to have 

 been the dog, and this animal is still used, as everyone 

 knows, as a beast of burden in the far North, and in 

 some European cities, particularly in those of Germany. 

 Subsequently the ox was domesticated, but it is probable 

 that for a vast period of time it was used for food pur- 

 poses, rather than as a beast of burden. And lastly 

 the horse, the worker par excellence, was made captive 

 by some Asiatic tribes having the genius of invention, 

 and in due course this fleetest of carriers and most 

 efficient of draught animals was introduced into all 

 civilized nations. 



Doubtless for a long time the energy of the horse 

 was utilized in an uneconomical way, through binding 

 the burden on its back, or causing it to drag the burden 

 along the ground. But this is inferential, since, as 

 we have seen, the wheel was invented in pre-historic 

 times, and at the dawn of history we find the Babylon- 

 ians driving harnessed horses attached to wheeled vehi- 

 cles. From that day to this the method of using 



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