A HISTORY OF SCIENCE 



the first person who discovered or asserted the identity 

 of Hesperus and Lucifer that is to say, of the morning 

 and the evening star. This was really a remarkable 

 discovery, and one that was no doubt instrumental 

 later on in determining that theory of the mechanics 

 of the heavens which we shall see elaborated presently. 

 To have made such a discovery argues again for the 

 practicality of the mind of Pythagoras. His, indeed, 

 would seem to have been a mind in which practical 

 common-sense was strangely blended with the capacity 

 for wide and imaginative generalization. As further 

 evidence of his practicality, it is asserted that he was 

 the first person who introduced measures and weights 

 among the Greeks, this assertion being made on the 

 authority of Aristoxenus. It will be observed that he 

 is said to have introduced, not to have invented, 

 weights and measures, a statement which suggests a 

 knowledge on the part of the Greeks that weights and 

 measures were previously employed in Egypt and 

 Babylonia. 



The mind that could conceive the world as a sphere 

 and that interested itself in weights and measures 

 was, obviously, a mind of the visualizing type. It is 

 characteristic of this type of mind to be interested in 

 the tangibilities of geometry, hence it is not surprising 

 to be told that Pythagoras "carried that science to 

 perfection." The most famous discovery of Pythag- 

 oras in this field was that the square of the hypotenuse 

 of a right-angled triangle is equal to the squares of the 

 other sides of the triangle. We have already noted 

 the fable that his enthusiasm over this discovery led 

 him to sacrifice a hecatomb. Doubtless the story is 



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