GENERALIZATION OF PRINCIPLES. 79 



tronomy. As a work on Dynamics, its merit is, 

 that it exhibits a wonderful store of refined and 

 beautiful mathematical artifices, applied to solve all 

 the most general problems which the subject offered. 

 The Principia can hardly be said to contain any 

 new inductive discovery respecting the principles of 

 mechanics; for though Newton's Axioms or Laws 

 of Motion, which stand at the beginning of the 

 book, are a much clearer and more general state- 

 ment of the grounds of Mechanics than had yet 

 appeared, they do not involve any doctrines which 

 had not been previously stated or taken for granted 

 by other mathematicians. 



The work, however, besides its unrivalled mathe- 

 matical skill, employed in tracing out, deductively, 

 the consequences of the laws of motion, and its 

 great cosmical discoveries, which we shall hereafter 

 treat of, had great philosophical value in the history 

 of Dynamics, as exhibiting a clear conception of the 

 new character and functions of that science. In his 

 Preface, Newton says, " Rational mechanics must be 

 the science of the motions which result from any 

 forces, and of the forces which are required for any 

 motions, accurately propounded and demonstrated. 

 For many things induce me to suspect, that all 

 natural phenomena may depend upon some forces 

 by which the particles of bodies are either drawn 

 towards each other, and cohere, or repel and recede 

 from each other: and these forces being hitherto 

 unknown, philosophers have pursued their re- 



