[This is the third of the re-posted articles, from 2008.]

For most of his life, and while not attending to farm duties, Wilson A. Bentley was captivated by the beauty of snow crystals. Perhaps then it should not be too surprising that he pondered the physical cause of their symmetry and intricacy. His thoughts turned to electricity as an explanation, perhaps influenced by his era's popular-culture infatuation with the new-fangled electrical devices. Though erring in the details, he was clearly onto something as I will show.

He considered that the crystalline surfaces had electric charges, with more charges concentrated at branch tips (1). When the tips of the branches overflowed with charge, the charges dribbled down the sides to produce ‘growth nuclei’ for the sidebranches. This process, he argued, could explain the symmetry of snow crystals:

"That the crystals, when permitted, attain to such a marvelous degree of symmetry and complicity, shows that the alignment of the growth nuclei, presumably tiny electric charges, is symmetrically regular to an almost unbelievable degree."

Here he connects electricity to the formation of sidebranches and the branch symmetry. In other writings, he connects snow electricity to growth rate, and snow electricity to lightning. In the specific details he was wrong, but in general he was surprisingly prescient. Snow crystals are indeed electric crystals, and the electricity itself is captivating. To see why, consider some of the amazing things that Mr Bentley’s electric crystals can do.

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