PHYSICAL AND HTfiRARY. 113 



nfeceflary to eXpla'm thefe phaenomena from 

 their true principles. In particular, ic 

 might be thought, cdriiillently with the 

 falfe notions advanced concerning the re- 

 fiftance of matter, that the reafon why a 

 body did not move forwards when a part 

 of it was broke off by a great force, was 

 this, that the inertia or refiftance to mo- 

 tion in that cafe became ftronger than 

 the power of cohefion. 

 Philosophers have fondly perplexed 

 themfelves with many fubtile queftions 

 Concerning the communication of motion j 

 and have perfifted, with the utmofl anxi- 

 ety, in a very fruitlefs inquiry, ho'w mo- 

 tion can pafs out of one body into ano- 

 ther ; as if motion was fomething that 

 could be fepa;rated from the moving bo- 

 dy, and infufed from one ifito the otherj 

 like water poured into a phial. But, not- 

 wichftanding all the intricacy of this af- 

 fair, it would appear to be ftill a greater 

 myftery, if one body in motioifi \^efe not 

 to move another lying freely at reft. It 

 is indeed only by experience that we learn 

 the laws of the communication of motion. 

 Vol. I. P For 



