Additional Notes, 407 



ing the idea from him, suggests it, not as a fixed oj-lnion, but 

 as a modest query, (see 23d query, subjoined to his Optics), 

 whether " vision is effected chiefly by the vibrations of an elaa- 

 tic medium, excited in the bottom of the eye by the rays of 

 light, and propagated along the solid, pellucid, and uniform, 

 capillaments of the optic nerve? And whether hearing is 

 effected by the vibrations of the same or of some other me- 

 dium, excited by the tremor of the air in the auditory nerves, 

 and propagated along the solid, pellucid, and uniform capilla- 

 ments of those nerves?" And so with regard to the other 

 $enses. What was thus suggested by Newton became a fun- 

 <3amental principle in Hartley's system, and has been consi- 

 dered by him and his followers as placed on the high ground 9f 

 ^emonsfration. 



Note CLLjj page 206. — An ingenious and learned friend, on 

 reading the assertion, in the abovementioned page, that " Presi- 

 dent Edwards appears to have been the first Cahinist who 

 avowed his belief so fully and thoroughly in the doctrine of 

 moral necessity as his boolj: indicates," made the following re- 

 marks : 



*' You have mistaken the fact with reference to president 

 Edwards. His great mind was, indeed, nobly exercised in the 

 defence of truth. He appears an original in the invention of 

 arguments against his adversaries, but not in discovering the 

 truths which he states respecting the liberty of the will. The 

 connection between motives and volitions, the liberty of choice 

 in man, and the necessity of the futurition of human volun- 

 tary actions; in short, every part of moral necessity consistent 

 with free agency, was embraced and understood before his day, 

 although not so successfully demonstrated as by him. You 

 should have taken notice of his son, Jonathan Edwards, D.D. 

 late president of Union college, in Schenectady. He was an 

 able metaphysician. Few works in the English language dis- 

 cover more penetration than his book on the LiUrtij of the 



wmr 



