and the Crystallization of Ice. 



411 



night to — 5° R, I have never seen snow in more pei-fect and 

 more variously-formed crystals than during this short and sudden 

 shower. Each grain fell single, and among the few which set- 

 tled on the glass or on the metal of my instruments, I could 

 distinguish six different forms. Doubtless many more I'emaincd 

 unobserved, for my attention was drawn in the mean time to a 

 more wonderful and quite novel phenomenon. Many of the 

 crystals began to melt the instant they touched a solid body, 

 and some, as it seemed to me, melted while still falling through 

 the air ; but in the next moment this was followed always by a 

 new congelation, the grain of snow assuming, not its previous 

 form, but another more complex. Thus, for instance, the most 

 simple crystals which I observed today, consisted of six thin 

 Fi?. 2 a. 



needles of ice, which adhered to each other like the diagonals of 

 a regular hexagon (fig. 2 a). When melting, each single ray of 

 this star contracted into a thicker cylinder of water, having about 

 half of its former length (fig. 2 b) ; but after a few moments 

 these cylinders were seen to congeal again, and changed thereby 

 into broader plates, sharpened at their outer edges by two planes 

 of a regular hexagonal prism. The whole crystal became thus 

 again an hexagonal star, but with broader and shorter rays than 

 it had before. 



Fig. 3i. 



Fig. .'^ c 



Other crystals, which had in the beginning siicli flat and Ijroad 

 rays (fig. 2 c), changed these by melting into feathered ones 



