18 



the same instant, by rays which cross each other with- 

 out any interruption, in all possible angles. But in 

 sounds which move through a gravitating resisting me- 

 dium, the case is quite different. For a multitude of 

 sounds, from different sonorous bodies, cannot be dis- 

 tinctly heard : particularly, when they come to the ear, 

 in many different directions. For the undulations of the 

 resitting medium, mixing with, and disturbing each 

 other, confuse the sensation, throwing ail together, in- 

 discriminately to the ear. Thus when a multitude of 

 people are all talking together, the ear receives only a 

 confused hum or murmur; whereas the eye can perceive 

 all or any one cf them distinctly and without confu- 

 sion. 



Indeed nothing is more sure, than that gravity, pres- 

 sure, resistance, and all those affections of bodies which 

 are termed their mechanical powers, are not intrinsic or 

 essential to them. For since matter is purely passive, 

 and can only act as it is acted upon, it follows, that the 

 active force or energy, which \ve observe through the 

 whole material system, must be the effect of some in- 

 trinsic, non-essential cause. And such a cause is light. 

 But then the actions of this can never be mechanically 

 accounted for. How this immechauical fluid acts upon* 

 other bodies, and determines their mechanical powers, 

 we can no more explain than how the soul acts upon the 

 .body, or the mind upon matter. But we are sure this is 

 not done by weight, pressure, resistance, or any me- 

 chanical property whatever. 



" But what are the general latvs of nature ?' They 

 are plainly th rules or principles, by which the Go- 

 vernor and Director of all things, lias determined to act. 

 Accordingly what we call mechanism, is indeed the free 

 agency and continued energy of the author and director 

 of nature. All the necessary motion of bodies there- 

 fore, and all the laws and forces whereby it is commu- 

 nicated and preserved, are the continued, regular will* 

 choice and agency of the first cause, and incessant mover 

 and preserver of the universe. 



