168 BOOK OP NATURE LAID OPEN. 



fact, as Mr. Derham observes, it is a subtile and pe- 

 netrating matter, " fit to pervade other bodies, to 

 penetrate into the inmost recesses of nature; to ex- 

 cite, animate, and spiritualize ; and, in short, to be 

 the very soul of this lower world " 



But what is very remarkable, this wonderful fluid, 

 so necessary for the existence of bodies, is also made 

 use of as a most powerful agent in the hand of Pro- 

 vidence for their destruction. It is a chaos contain- 

 ing all kinds of menstrua, and consequently possess- 

 ing powers for dissolving all bodies, by which means 

 many things, which would prove nuisances to the 

 world, are put out of the way, and reduced to their 

 first principles 



The air, as well as being the medium of light and 

 vision, is also the great vehicle of sound, serving to 

 convey to the ear, by its undulating motion, all that 

 diversity of noise and modulation of tone, necessary 

 to warn us of impending danger, or attract our at- 

 tention and regard. " As I walk across the streets 

 of London," observes Mr. Hervey, "with my eye en- 

 gaged on other objects, a dray, perhaps, with all its 

 load, is driving down directly upon me; or, as I 

 ride along the road, musing and unapprehensive, a 

 chariot and six is whirling on with a rapid career, 

 at the heels of my horse. The air, like a vigilant 

 friend In pain for my welfare, immediately takes the 

 alarm ; and while the danger is at a considerable dis- 

 tance, despatches a courier to advertise me of the 

 approaching mischief. The air wafts to our senses 

 all the modulations of music, and the more agreeable 



