J5 



4. Whoever will be at the pains attentively to read 

 what Aristotle hath written concerning light, without 

 having recourse to the ridiculous interpretations that 

 have been put upon his words, *ill clearly discern^ 

 that he was far from being so unacquainted with the 

 truth in this case, as is generally thought. He defines 

 it to be the action of a subtle, pure, and homogeneous 

 matter ; and Philoponus, explaining the manner in 

 which this action was performed, makes use of the 

 instance of a long string, which being pulled at one 

 end, will instantaneously be moved at the other. In 

 that very place, he resembles the sun to the man who 

 pulls the string: the subtle matter, to the string itself; 

 and the instantaneous action of the one, to the move* 

 ment of the other. Simplicius, in his commentary 

 upon this passage of Aristotle, expressly employs the 

 motion of a stick, to intimate how Iight,acted upon by 

 the sun, may instantaneously impress the organs of 

 sight. The comparison of a stick, to convey an idea 

 of the celerity withwhich light may communicate itself, 

 seems to hare been first of all made use of by Chry- 

 sippus. 



