36 SCIENCE OF THE GREEKS. PT. I. 



days were held, even by such men as Pythagoras or Galen ; 

 but in this book we have only to try to understand the real 

 facts which have been discovered ; and there is no doubt 

 that the Greeks, by a patient study of nature, and by making 

 real and careful observations and experiments, laid the found- 

 ations of much of the knowledge which we have carried 

 so much farther in modern times. The moment they began 

 merely to repeat the teachings of others, instead of trying 

 and proving the truth of them, they made no more discov- 

 veries, but lost a great deal they had gained. For a mere 

 reading of books will not teach science ; and if you admire 

 these men for making great discoveries, and would like to 

 be a discoverer yourself, you must not be content with 

 knowing what has been done, but must set to work as they 

 did, and observe and make experiments for yourself. 



Chief Works consulted. Draper's 'Intellectual Development in 

 Europe ;' Lewis's ' Astronomy of the Ancients ;' ' Encyclopaedia Bri- 

 tannica,' art. 'Astronomy;' Herschel's 'Astronomy;' Baden Powell's 

 'History of Natural Philosophy;' Lardner's 'Cyclopaedia,' 1834; 

 Sprengel's ' Histoire de la Medecine,' 1815 ; Grant's 'History of 

 Physical Astronomy;' Lange's ' Geschichte des Material ismus ;' Rees' 

 ' Encyclopaedia ;' Whewell's ' History of Inductive Sciences.' 



