NATURE FOR ITS OWN SAKE 



tffsts and 

 fogs. 



tary flash upon the scene. The swirl and the 

 swish of the elements, especially on the sea or 

 on the plains, the sublimity of the tempest, ap- 

 peal to us perhaps ; but onr eyes are almost 

 useless. Nothing so darkens the earth as night 

 and rain clouds under a moonless sky. 



It is, apparently, a very different light that 

 we see when the clouds are not above us, but 

 around us. A mist or fog is merely a cloud 

 formed close to the ground, and is not different 

 from the cloud that is about one at times on a 

 mountain-top, except that the fog appears to 

 be more luminous and to have more color. 

 Doubtless something of this appearance is due 

 to the thinness of the bank. It generally forms 

 with a clear sky overhead, and is sometimes not 

 higher above the earth than a house-top, though 

 it is often a hundred or more feet in thickness. 

 When the bank is shallow we are surrounded by 

 diffused and refracted light, and an upward 

 glance in the direction of the sun shows us a 

 white light seen as through alabaster. This 

 same light is sometimes seen in the early morn- 

 ing illuminating the whole landscape when the 

 fog has lifted a thousand or more feet above the 

 earth and is spread out into a thin, gauze-like 

 sheet. The thinness of the sheet prevents ob- 



