6 INTRODUCTION. 



chanics were studied for their own sakes ; but they 

 also supplied ideas, language, and reasoning to 

 other sciences. If the Greeks had not cultivated 

 Conic Sections, Kepler could not have superseded 

 Ptolemy; if the Greeks had cultivated Dynamics 1 , 

 Kepler might have anticipated Newton. 



1 Dynamics is the science which treats of the Motions of 

 Bodies, Statics is the science which treats of the Pressure of Bodies 

 which are in equilibrium and therefore at rest. 



