An Introduction to a Biology 



of a device, the axle, whereby the wheel went along 

 with the cart ; in the activities of peace this in- 

 vention greatly facilitated the work of transporta- 

 tion ; and in warfare it put great power into the 

 hands of the men who used it, by enabling them 

 to do the next best thing to being in more than one 

 place at the same time namely, to get from one 

 place to another in a very much less time than 

 their adversary. " And the Lord was with Judah ; 

 and he drave out the inhabitants of the mountain ; 

 but could not drive out the inhabitants of the 

 valley, because they had chariots of iron " (Judges 

 i. 19). 



It was not, however, only by taking ofi the brake 

 imposed by gravity and friction that the wheel let 

 loose the avalanche of man's material prosperity. 

 The potter's wheel gave him utensils which, amongst 

 other things, enabled him to carry and store water, 

 and thus lengthened the apron-strings which bound 

 him to springs and rivers. The spinning-wheel 

 contributed to warmth and comfort. 



The wheel could not have been invented before 

 evolution had got on to the extra-corporeal stage 

 in man, because the wheel must, whilst fitting closely 

 round its axle, be absolutely separate from it. Such 

 an organ in a vertebrate would have to consist of 

 a bony disc, with either a hole through its centre, 

 or with an axle which was part of it and which fitted 

 into a horizontal hole in the skeleton, such as the 

 acetabulum. Such an organ could not be used until 

 it was fully grown and had come to consist only of 

 dead bone, because it could not be used until it had 

 become a separate piece from the axle, after which 



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