A HISTORY OF SCIENCE 



achievement of the Greek astronomers is stupendous. 

 To have clearly grasped the idea that the earth is 

 round is in itself an achievement that marks off the 

 classical from the Oriental period as by a great gulf. 



In the physical sciences we have seen at least the 

 beginnings of great things. Dynamics and hydro- 

 statics may now, for the first time, claim a place 

 among the sciences. Geometry has been perfected and 

 trigonometry has made a sure beginning. The con- 

 ception that there are four elementary substances, 

 earth, water, air, and fire, may not appear a secure 

 foundation for chemistry, yet it marks at least an 

 attempt in the right direction. Similarly, the concep- 

 tion that all matter is made up of indivisible particles 

 and that these have adjusted themselves and are 

 perhaps held in place by a whirling motion, while it is 

 scarcely more than a scientific dream, is, after all, a 

 dream of marvellous insight. 



In the field of biological science progress has not 

 been so marked, yet the elaborate garnering of facts 

 regarding anatomy, physiology, and the zoological 

 sciences is at least a valuable preparation for the 

 generalizations of a later time. 



If with a map before us we glance at the portion of 

 the globe which was known to the workers of the 

 period now in question, bearing in mind at the same 

 time what we have learned as to the seat of labors of 

 the various great scientific thinkers from Thales to 

 Galen, we cannot fail to be struck with a rather star- 

 tling fact, intimations of which have been given from 

 time to time the fact, namely, that most of the 

 great Greek thinkers did not live in Greece itself. As 



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