io HISTORY OF SCIENCE. 



may have acquired such geological truths as are here implied; but we 

 are inclined to think that his maxim did not embody them, nor did it 

 merely reflect the superstitious veneration of the Egyptians for the Nile. 

 We regard the maxim as really a generalization of facts observed by 

 the philosopher, but too hasty and too wide a generalization. We may 

 take for granted that Thales could not have overlooked the fertilizing 

 effects produced by the annual overflow of the Nile, and that in his 

 native city of Miletus the sea would furnish the people with an unfailing 

 supply of food. Thales, however, probably remarked that no seeds 

 germinate in the absence of moisture, while on the other hand, plants 

 grow without requiring any other visible material than water.* Again, 

 Thales may have noticed that the bodies of animals are built up as it 

 were in water, and are saturated with it. He recognized, it is said, 

 the importance of water as an element of the human organization.^ 

 Thales went beyond such facts as these, and concluded that even heat 

 was a product of humidity, for seeing that the sun and stars daily rose 

 from the ocean, and with equal regularity sank into it again, he sup- 

 posed that their fires were in some way nourished by the sea. The 

 selection by Thales of water as the primordial element harmonizes 

 curiously with the love of the old Greeks for the sea that sentiment 

 which prompted Xenophon's soldiers to raise a great shout when, after 

 their long journey, they at last beheld the sea from the Thechian moun- 

 tain, and embracing each other with tears in their eyes, they cried aloud, 

 " 6a\a<r(ra I 6a\a<T<ra I " (" the sea ! the sea ! ") 



The disciples and successors of Thales sought, like him, the single 

 or fundamental principle out of which, as they conceived, everything 

 had been produced. This notion of a primordial principle distinguishes 

 indeed the Ionian school of philosophers. Thus, while ANAXI>IANDER 

 (B.C. 611 545), the friend and pupil of Thales, continued to teach 

 many of his master's doctrines, he regarded the fundamental principle 

 out of which he supposed everything had been made, as something 

 more subtile than water, though not so thin as air. To this philosopher 

 the invention of the sundial has been attributed, but more probably 

 he derived the knowledge of it from the Babylonians. It is impossible, 

 amid the conflicting statements made by ancient writers, to determine 

 always the original authors of scientific doctrines and inventions. In 

 many cases, perhaps, the pupil was only promulgating the doctrines or 

 making known the inventions of his master. Anaximander gave a very 

 judicious answer to a question which seems to have occupied the 

 thinkers of his time, who asked him how it happened that the earth 

 was sustained in its position. He said that the earth being in the 

 centre of the universe, there could be no cause to solicit its movement 



* To make this view clear to the young reader we need only remind him of the familiar 

 expedient of growing hyacinths in glasses filled with water. 



t Modern physiologists tell us that water constitutes six-sevenths of the weight of the 

 human body. 



