294 NATURAL THEOLOGY. 



XVI. 



ON THE RAYS OF LIGHT, THEIR REFRACTION AND 

 REFLECTION. 



The nature of light has ever been a subject of 

 controversy. It was Newton's explanation that 

 luminous objects give out particles of inconceiva- 

 ble minuteness, and moving with extreme velocity. 

 " "V^Hiat mere assertion," says Sir John Herschel, 

 " will make any man believe that, in one second 

 of time, in one beat of the pendulum of the clock, 

 a ray of light travels over 192,00 miles; and 

 would therefore perform the tour of the world in 

 less time than a swift runner would make one 

 stride V In short, there is nothing like it but the 

 influence of attraction ; which is so instantaneous 

 as to admit of no calculation of time at all. 



A different theory from that of Newton was 

 suggested by Huyghens, who supposed a highly 

 elastic fluid to fill all space, and which, when mo- 

 ved, produced the eftects ascribed to light. In- 

 stead of minute particles diverging from the lumi- 

 nous body, he substituted waves or vibrations, 

 propagated through this elastic ether. The late 

 Dr. Young, and some continental philosophers 

 more recently, took up this hypothesis, and sup- 

 ported it by ingenious experiments. But notwith- 



