In the pursuit of this effort only, the crystal becomes at once both a beautiful, interesting and harmless channel of pleasure and instruction, shorn of dangers, and rendered conducive to mental development.

They are composed of the phosphate and oxalate of lime; but there is great difference of opinion as to their use in the economy of the plant, and one of the French philosophers endeavoured to prove that crystals are the possible transition of the inorganic to organic matter.

But crystals are hard bodies; they resist all injuries, they can bear a beating without breaking; for they are regularly formed, and complete in all their parts.

Snow-crystals, the flowers of the mountain clouds, are frail, beautiful things, but terrible when flying on storm-winds in darkening, benumbing swarms or when welded together into glaciers full of deadly crevasses.