ANCIENT SCIENCE. 



It is stated also that Thales was acquainted with the rotundity of 

 the earth, and the true cause of lunar and solar eclipses. Nay, more, 

 it appears that he actually predicted the occurrence of an eclipse, 

 and that the prediction was fulfilled. The ancient historians assert that 

 this eclipse interrupted a great battle which was commencing between 

 the Medes and Persians, and from this circumstance it has been in- 

 ferred that the eclipse in question must have taken place in the year 

 B.C. 585. The truth of this ancient statement having been doubted, 

 our present Astronomer-Royal, Sir George Airey, not long ago calcu- 

 lated back the dates of the solar eclipses which have occurred about the 

 period in question, and he found that on the 28th of May, B.C. 585, 

 there was a solar eclipse which was total for the region of Asia Minor. 

 The calculation of the exact period of a solar eclipse requires the 

 knowledge of a great number of facts which could not have been 

 known to the Egyptians or to Thales. It is therefore surmised that 

 Thales had in the East acquired a knowledge of a certain cycle, or long 

 period, in which eclipses occur with a certain regularity ; such a period 

 was, it is said, known to the Chaldeans, among whom also Thales 

 spent some time. By his knowledge of the cycle he may have been 

 able to predict an eclipse, and he would no doubt have allowed some 

 considerable limits between the dates within which the prediction 

 might be fulfilled. 



There is a fact which it is expressly stated Thales was acquainted 

 with, and which for centuries remained an isolated fact, although it 

 attracted some notice from the curious. It is the remarkable property 

 of amber to attract little bodies after it has been rubbed with a cloth. 

 This circumstance is one of the fundamental facts of that extensive 

 branch of science we now call electricity, from the Greek name for 

 amber (cAcKi-poi/). 



But perhaps the most remarkable doctrine of Thales was one which 

 displays in an extraordinary degree that seeking after generalization 

 which has been already referred to as the great aim in science. Thales 

 was the first on record who referred all things to a common origin, or 

 supposed them to be produced from one material. He said, "all things 

 are produced from water" This appears to us at the present day a 

 strange conclusion, for we are unacquainted with the facts upon which 

 the philosopher based his opinion ; and the sense intended to be 

 attached to the words is by no means certain. Some moderns think 

 that Thales is entitled to very little credit for this famous maxim, and 

 they suggest that he acquired the notion in Egypt, from the common 

 people, who, seeing that the water of the Nile made their soil fertile, 

 and, in fact, furnished them with their means of subsistence, would 

 attach the greatest importance to water. On the other hand, it has 

 been supposed that Thales had observed, that the earth itself showed 

 signs of having been deposited from water, as we now know by the 

 teachings of geology. It is of course quite possible that the philosopher 



