4 Experimental Philosophy. [Lecture 1 . 



men or cattle ; it sometimes levels to the ground 

 the proudest edifices, and sets on fire the loftiest 

 trees or buildings. You have probably never 

 once thought what can be the cause of this 

 thunder and lightning. But will you not be 

 astonished to see it imitated on a smaller scale, 

 the same noise excited, a rapid fire sent forth 

 like that, and producing similar effects ? 



You see every day the clouds collected over 

 your heads, and passing hither and thither, as 

 directed by the wind. You see them assume 

 different shapes and forms ; sometimes gathering 

 into a large thick mass, at others breaking into 

 small divisions. What are the clouds made of, 

 think ye? Whence do they come? Why do 

 they appear and disappear ? Why do not they 

 fall down immediately upon the ground, as you 

 see other bodies ? 



The clouds, you will probably guess, are water, 

 because you see rain occasionally fall from them, 

 and sometimes hail and snow. But how is water 

 supported in the air? Why do the clouds at 

 some times drop only rain, and at others hail or 

 snow ? You will say hail and snow fall only in 

 cold weather. But why is snow of that fine 

 flaky consistence like feathers? And why is 

 hail in little round balls ? All this may be ex- 

 plained. 



You have doubtless observed that beautiful 

 coloured arch in the heavens, which, from its 

 appearance during rain, has been called the rain" 



