An Introduction to a Biology 



" Wlieelbearers," or Rotifera ; for it shows that 

 they thought of the essence of a wheel, not analytic- 

 ally, in terms of matter, as a thing made of hub, 

 spokes and rim ; but intuitively, in terms of per- 

 formance, simply as " that which revolves." 



The wheel put power into man's hands in a variety 

 of w^ays. It cannot be said that the pulley enabled 

 him to lift weights heavier than he had lifted before, 

 for the horizontal monoliths of Stonehenge were 

 probably lifted without its aid. But the pulley cer- 

 tainly facilitated and expedited to a very great 

 extent the labour of lifting. The windmill and the 

 water-wheel are results of the utilisation of tre- 

 mendous natural forces which could not have been 

 impressed into the service of man (on land) but 

 for the previous invention of the wheel. But the 

 stream and the wind cannot be said to have been 

 subjugated by man to the extent that steam, elec- 

 tricity, petrol and gas have. The stream and the 

 wind serve man at their pleasure and not at his ; 

 it is natural, therefore, that it is in association with 

 the more completely domesticated and controllable 

 forces like steam, electricity and the rest that wheels 

 should have attained to the highest stage of their 

 differentiation. How essential a part in those extra- 

 corporeal organs of man which we call machinery 

 the wheel plays is illustrated by the fact that in 

 the picture called up in the mind by the word 

 " machinery " wheels are the dominant feature. How 

 essential a part the wheel played in the origin of 

 machinery may be gathered from the fact, which is, 

 I think, obvious, that without it it is difficult to see 

 how steam, electricity and gas could have been har- 



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