22 HISTORY OF MECHANICS. 



statement shows a clearness of conception with 

 regard to the cause of accelerated motion, which 

 Galileo himself was long in acquiring. 



Though Benedetti was thus on the way to the 

 First Law of Motion, that all motion is uniform and 

 rectilinear, except so far as it is affected by extrane- 

 ous forces; this Law was not likely to be either 

 generally conceived, or satisfactorily proved, till the 

 other Laws of Motion, by which the action of Forces 

 is regulated, had come into view. Hence, though a 

 partial apprehension of this principle had preceded 

 the discovery of the Laws of Motion, we must place 

 the establishment of it in the period when those 

 Laws were detected and established, the period of 

 Galileo and his followers. 



