PHYSICAL AND LITERARY, r^ 



fight can move thro' light in all imaginable 

 diredtions, without occafioning the leaft 

 perceivable confufion or deviation from its 

 redilinear courfe. Many have been induced, 

 from this confideration, to believe it incor- 

 poreal ; and all who have thoroughly weigh-. 

 cd the difficulty, have feert the neceffity of 

 afcribing a fubtility to it incomparably greater 

 than we ^re led, by -asiy phanomenay to afcribe 

 to any other fpecies of bodies in Nature. 

 There is no phyfical point in the vifible ho- 

 rizon which does not fend rays to every other 

 point J no ftar in the heaven which does 

 noC fend rays to every other ftar : the whole 

 horizon is filled with a fphere of rays from 

 every point in it j and the whole vifibfe uni- 

 verfe, with a fphere of rays from every ftar. 

 In fhort, for any thing we know, there are 

 rays of light joining every two phyfical points 

 in the univerfe, and that iaa- contrary diFe<5^i- 

 pns J except where opaque bodies iriter- 

 veen. 



.2. Those who fuppofe that light is nothing 

 clfe than vibrations or pulfes propgated 

 thro' a fubtile elaftic medium from the vifible 

 objeft to the eye, may perhaps remove the 

 dfificulty by afcribing a fafficient minute- 



nefs 



