44 THE REALITIES OF MODERN SCIENCE 



developed a water screw for pumping, which was used 

 in Egypt for irrigation ; how he invented machines, 

 like catapults, for hurling huge stones, which were 

 used in the defense of Syracuse against the Romans in 

 212 B.C. ; and how, when the Romans finally captured 

 the city, he was killed by a Roman soldier whom he 

 urged not to spoil the circles of the geometrical problem 

 which he was diagraming on the sand, are interest- 

 ing stories which the reader may find recorded in his- 

 tories of science. 



How Euclid, Archimedes, and other of these Greek 

 philosophers developed geometry; how, for example, 

 Archimedes arrived at the value of pi, TT, the ratio of 

 the circumference of a circle to its diameter, as being 

 something between 3y and Sfr, and of their astro- 

 nomical theories, the student will also find interesting 

 reading. 1 



Despite, however, the many contributions of the 

 Greeks to science, they frequently relied too much on 

 their mental processes and not enough on experiment. 

 The phenomena of nature had not at that time been 

 sufficiently 2 observed for correlation. They usually 

 had too meager data on which to base conclusions. 

 Of similar errors the popular science of to-day is oc- 

 casionally guilty. The Greeks also made a distinc- 

 tion between theory and practice which had some re- 



1 Cf . Tyler and Sedgwick, "A Short History of Science." The 

 Macmillan Company, 1917. 



2 But some Greeks recognized this, as is seen in a statement of 

 Aristotle that ' ' the phenomena are not yet sufficiently investigated ; 

 when they are, then one must trust more to observation than to 

 speculation, and to the latter no further than it agrees with the 

 phenomena." 



