182 FORMATION OF COMPOUND BODIES. 



SIR ISAAC NEWTON, in particular, employs the 

 term, attraction, in a manner the most inde- 

 finite that can possibly be conceived ; it neither 

 denotes aiiy particular kind, or manner, of 

 action^ nor the principal cause of such action ; 

 but the tendency only in general, a conatus 

 accidendi, to whatever cause such effect may be 

 owing ; whether to a power inherent in the bo- 

 dies themselves ; or to the impulse of an external 

 agent. In his optics, he says, Attraction may 

 be performed by impulse, or some other means ; 

 and he uses the word to signify any force, by 

 which bodies tend towards one another; and 

 again, in his first Principles, he notes, " that 

 he uses the words, Attraction, Impulsion, and 

 Propension, to the centre, indefinitely ; and 

 cautions the reader not to imagine, that by 

 attraction, he expresses the modes of the action 

 in the different cases thereof, as if there were 

 any proper powers in the centres, which, in 

 reality, are only mathematical points, or as if 

 the centres, could attract : he considers centri- 

 petal powers as attractions ; though, physically 

 speaking, it were more just to call them Im- 

 pulses ; and adds, that what he calls attraction, 

 may possibly be effected by impulse, though 

 not a common, or corporeal, impulse ; or after 

 some manner unknown to us." 



Vague and indefinite, in its application, as 

 the term attraction actually is, when thus em- 



