Mineral Evolution. 109 



able. Ten thousand forms of crystals are now known, 

 new ones are constantly being discovered, and new 

 ones are probably as constantly being evolved. 



Section 2. Snow Flakes : 



In these beautiful geometrical designs there is no 

 mere aggregation of molecules and crystals into huge 

 enlargements of their own semblance, but a cohesion 

 of perfectly formed molecular crystals into an artistic 

 device. The law of mere aggregation thus yields to 

 a higher force — a force, moreover, not unacquainted 

 with art, for it produces illimitable designs. The 

 artist in nature, in effect, here steps upon the scene. 

 Who the artist is, and what the artistic laws are, we 

 have already stated, and the following facts reveal. 



A snow-flake is composed of oxygen and hydrogen, 

 hence is a dual or sexual elementary compound. It 

 is, however, not globular — like a drop of rain — but a 

 fleecy mass of minute ice crystals. These crystals 

 assume all shapes, from a confused pattern to a 

 definite geometrical model. The perfect form is 

 invariably hexagonal ; but its design, barring this re- 

 striction, is illimitable. As snow-flakes generate in 

 the upper atmosphere, they necessarily originate from 

 floating particles of vapour. Each of these particles 

 or snow-molecules is in all probability a star or sphere 

 of six radiating points ; hence, in the cohesion of those 

 stars or spheres, the final form of snow-flakes inevit- 

 ably depends upon the chance environing conditions 

 attending their growth. A snow-molecule may thus 



