16 



and down incessantly till the music ceased. So it 

 may be literally true, 



Sueius Amphion lenire tigres. 



Light is propagated about two hundred thousand 

 miles in a second, after the very same munner as sound. 

 The sun impresses the contigious part of its visive at- 

 mosphere : (light seems to be the atmosphere of the sun, 

 as air is of all opake bodies). That part impress ebthe 

 next, and so on, till it reaches the eye. 



All sensation is from contact of feeling ; and when 

 the object is not in immediate contact with the organ it 

 affects, touches, or impresses, by an interposed medium. 

 By this means the soul perceives or feels the object by 

 the proper organ : and thus, seeing is in effect, the feel- 

 ing of the eye -, hearing, the feeling of the ear. 



From all our experiments it appears, that the particles 

 of light are extremely minute. Probably they are the 

 very smallest and last divisions of matter which, being 

 perfectly solid, cannot receive any other form : sa 

 minute are they as to pass freely even through the 

 pores of glass, which no other fluid can penetrate. 



All other bodies are immersed in this universal fluid, 

 the conation medium of all their actions on each other. 

 But amidst all the changes of compound bodies, all the 

 forms they successively put on, this simple element re- 

 mains for ever fixed and immutable. 



As to fire, or condensed light, all bodies whatever fly 

 or recede from it, in proportion to its den-ity: and this 

 seems to be its fir^t and most essential property, that no 

 other body can exist with it, or bear its immediate 

 action. So far as it prevails, it dissolves the closest and 

 strongest cohesion of parts in all other bodies, and re- 

 duces them into so extremely minute particles, that they 

 evaporate in air. And herein is an essential difference . 

 2 



