A HISTORY OF SCIENCE 



mind of Anaxagoras between the friction of the clouds 

 and the observed electrical effects generated by the 

 friction of such a substance as amber. To make such 

 a suggestion doubtless would be to fall victim to the 

 old familiar propensity to read into Homer things that 

 Homer never knew. Yet the significant fact remains 

 that Anaxagoras ascribed to thunder and to lightning 

 their true position as strictly natural phenomena. 

 For him it was no god that menaced humanity with 

 thundering voice and the flash of his divine fires from 

 the clouds. Little wonder that the thinker whose 

 science carried him to such scepticism as this should 

 have felt the wrath of the superstitious Athenians. 



Biological Speculations 



Passing from the phenomena of the air to those of 

 the earth itself, we learn that Anaxagoras explained an 

 earthquake as being produced by the returning of air 

 into the earth. We cannot be sure as to the exact 

 meaning here, though the idea that gases are im- 

 prisoned in the substance of the earth seems not far 

 afield. But a far more remarkable insight than this 

 would imply was shown by Anaxagoras when he as- 

 serted that a certain amount of air is contained in 

 water, and that fishes breathe this air. The pas- 

 sage of Aristotle in which this opinion is ascribed to 

 Anaxagoras is of sufficient interest to be quoted at 

 length : 



" Democritus, of Abdera," says Aristotle, " and some 

 others, that have spoken concerning respiration, have 

 determined nothing concerning other animals, but 

 seem to have supposed that all animals respire. But 



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