xii CONTENTS 



CHAPTER XV 



KEPLER : PIONEER OF THE MODERN IDEAS OF 

 NATURAL LAW 



PAGE 



He was the first to undertake to reduce natural phenomena to 

 mathematical formulae He was the forerunner of Newton in 

 the ideas of gravitation . . . . . .183 



CHAPTER XVI 



GALILEO AND THE OPTIC TUBE 



He was the true inventor of the telescope His discoveries as con- 

 trasted with the meagreness of his resources His greatest work 

 was his investigation of the laws of motion and his foundation 

 of dynamics . . . . . , . 195 



CHAPTER XVII 



THE ADVANCE TOWARD A RATIONAL WORLD CONCEPTION 



Ideas and contributions of Bacon, Descartes, Gassendi, and Hobbes 

 Descartes was the first distinctly to picture the world as a 

 mechanism 211 



CHAPTER XVIII 



THE TRUE GRANDEUR OF THE SUN 



The first accurate measures of the sun's distance and size by 

 Domenico Cassini The amazing change which had already 

 come over European thought .... : * 225 



CHAPTER XIX 



THE DEVELOPMENT OF MECHANICS : THE 

 FORERUNNERS OF NEWTON 



Rise of the great mathematical school of the seventeenth century 

 Doctrine of inertia The discoveries of Torricelli Many 

 minds on the edge of the law of gravitation . . .237 



