210 STUDIES OF NATURE. 



tion. " The Earth," faid he, " carries along, rn 

 " like manner, the rotation of the two balls, m 

 ^' it's own movement. Were they to be (hot off 

 " in a perpendicular diredion, they would fall 

 ** back precifely on the point from whence they 

 *' were emitted." As axioms are not very expen- 

 live, and ferve to cut fhort all diinculties, he fub- 

 joined this as one : " The motion of a great body 

 abforbs that of a fmall." If this axiom be founded 

 in truth, replied I, the ball dropped from the- 

 top of the maft of a fliip under fail, ought not to 

 fall back clofe to the bottom of the maft; it's 

 motion ought to be abforbed, not by that of the 

 veffel, but by that of the Earth, which is far 

 the greater body. It ought to obey only the di- 

 reftion of gravity ; and, for the fame reafon, the 

 Earth ought to abforb the motion of the bullet 

 which is going along with it toward the Eaft, and 

 force it back into the cannon from which it if- 

 fued. 



1 was unwilling to pu (h this difficulty any far- 

 ther ; but I remained, as has frequently happened 

 to me, after the moft luminous folutions of ouï 

 fchools, ftill more perplexed than I was before. I 

 began to call in queftion the truth of not only a 

 fyftem and of an experiment, but what is worfe» 

 of an axiom. Nvot that 1 rejed; our planetary fyf- 

 tem, fuch as it is given us; but I admit it for the 



fame 



