36 WONDERS ON A PANE OF GLASS. 



has remained for any length of time upon the ground. The 

 great flakes which fall in relatively mild weather, when the 

 temperature borders upon freezing-point, are often nothing 

 better than masses of small amorphous atoms of ice ; to get 

 at the crystals, you must remove the kind of icy varnish which 

 encases them. 



For the accurate observation of the crystallisation of water 

 which precipitates itself in the air, we have at our disposal a 

 means as simple as convenient a pane of glass. All we have 

 to do is to arrange everything in such a manner that the con- 

 gelation shall be both slow and certain; on this condition 

 alone can we obtain well-defined crystals. A cold room is 

 best adapted for this kind of experimentation ; and thus you 

 will frequently see deposited upon the window-glass, in an 

 uninhabited chamber, some exceedingly graceful designs, as 

 follow. 



These are as- 

 teriae, arbor- 

 escent, and leaf- 

 like crystals, 

 imitating the 

 beautiful foli- 

 age of ferns and 

 Fig 7 mosses. The 



severer the cold, the more regular, be it understood, is the 

 formation of these crystals. 



Owing to its dazzling whiteness, snow is a great reflector of 



