8 PROGRESS OF SCIENCE. 



several of the geometrical propositions we have in Euclid ; 

 he also taught that WATER is the origin of everything that 

 exists a wrong doctrine, but one, nevertheless, which proves 

 him to have been an OBSERVER of nature. 



It is probable that much of all this was Egyptian know- 

 ledge, for he is known to have visited the valley of the Nile. 



610 547. Anaximander introduced the use of the 

 GNOMON into Greece (from Egypt possibly) which shows 

 that he was a practical observer; invented the SUN DIAL 

 teaching the Greeks how to measure the time of day by 

 the shadow of a rod cast by the sun ; he understood the 

 phases of the moon ; made a MAP of the known world, 

 being thereby the earliest practical geographer known to us. 



566 470. Pythagoras, the famous philosopher, ex- 

 hibited the spherical shape of the earth, made the assertion 

 that the EARTH MOVES in the heavens, although he failed 

 to see that it moves round the sun ; he detected the evening 

 star and the morning star, to be one and the same planet. 

 He does not appear, as it is often asserted, to have enter- 

 tained the right theory regarding our solar system, although 

 some of his disciples (Philolaus amongst others) seem to 

 have suspected it.* He devised the square multiplication 

 table which bears his name ; he formulated and demonstrated 

 the famous XLVIIth proposition in Euclid, which proves 

 him to have been a good mathematician. He might be 

 called the FOUNDER OF GEOLOGY, for he stated that the 

 sea-shells we find on land and in rocks were deposited by 

 the sea, and he understood from what he had observed in 

 Egypt the process of formation of new lands by rivers 

 depositing mud at their mouths. As a physicist, he is said 

 to have made a MONOCHORD, and shown how musical sounds 

 are produced on a stretched string, in accordance with a 

 mathematical scale. 



540 500. Xenophanes asserted that the fossil impres- 

 sions of animals and plants "were real remains of living 

 creatures, and that the mountains in whose rocks they were 

 found must at an earlier period have stood under water." 



* Philolaus said : "The earth and planets move in oblique circles (or 

 ellipses) about fire, as the sun and moon do." 



