226 EVOLUTION OF THE SCIENTIFIC INVESTIGATOR. 



sonic, was a powerful factor in the same (lii'cctioii. The result was 

 that, in keeping geometrv pure from ideas which did not belong to 

 it. it failed to form what might otherwise have been the basis of 

 physical science. Its founders missed the discovery that methods 

 similar to those of geometric demonstration could be extended into 

 other and Avider fields than that of sjoace. Thus, not only the devel- 

 opment of applied geometry, but the reduction of oth(>r conceptions 

 to a rigorous mathematical form was indefinitely postponed. 



Astronomy is necessarily a science of observation pure and simi)le, 

 in which experiment can have no place except as an auxiliary. The 

 vague accounts of striking celestial phenomena handed down by the 

 priests and astrologers of antiquity Avere followed in the time of the 

 Greeks by observations having, in form at least, a rude approach to 

 precision, though nothing like the degree of precision that the as- 

 tronomer of to-day would reach wath the naked eye, aided by such 

 instruments as he could fashion from the tools at the command of the 

 ancients. 



The rude observations connnenced by the Babylonians were con- 

 tinued with gradnall}^ improving instruments — first by the Greeks 

 and afterwards by the Arabs — but the results failed to afford any 

 insight into the true relation of the earth to the heavens. AMiat 

 Avas most remarkable in this failure is that, to take a first step for- 

 Avard AA'hich would have led on to success, no more Avas necessary 

 than a course of abstract thinking A^astly easier than that required 

 for Avorking out the problems of geometry. That space is infinite is 

 an unexpressed axiom, tacitly assumed by Euclid and his successors. 

 Combining this Avith the most elementary consideration of the prop- 

 erties of the triangle, it Avould be seen that a body of any giA^en size 

 could be placed at such a distance in space as to appear to us like a 

 point. Hence, a l)ody as large as our earth, AAhich Avas knoAvn to be 

 a globe from the time that the ancient Phamicians navigated the 

 ^lediterranean, if placed in the heaAcns at a sufficient distance, 

 Avould look like a star. The obvious conclusion that the stars might 

 be bodies like our globe, shining either by their own light or l)y that 

 of the sun. would haA^e been a first step to the understanding of the 

 true system of the Avorld. 



'J'hei-e is liistoric evidence that (his de(hiclion did not wholly es- 

 cap(> the (jireek thinkers. - It is true that the critical student Avill 

 assign little weight to the curnMit belief that the A^ague theory of 

 Pj'thagoras — that fire AA-as at the center of all things — imi)lies a con- 

 ce])ti()n of the heliocentric theoi-y of the solar system. But the testi- 

 mony of Archimedes, confused though it is in form, leaves no serious 

 doubt that Aristarchus of Samos not only propounded the A'ieAV that 

 the earth rcA'olA^es both on its own axis and around the sun, but that 

 he correctly removed the great stumbling-block in the AAay of this 



