12 ROUND THE YEAR 



In the northern countries of Europe at least the 

 crystalline form of snow must have been observed 

 very long ago, but nothing was said about it in books 

 till the 1 2th century, when Albertus Magnus remarked 

 that snow-flakes had the form of a star. Olaus 



FIG. 3. Snow-crystals, photographed by Dr. R. Neuhauss. From Prof. G. 

 Hellmann's Schneekrystalle. 



Magnus, in his History of the Northern Nations 

 ( T 555) figures snow-flakes, but so wretchedly that he 

 (or his engraver) had hardly recognised that they are 

 always angular, much less that the angles are constant. 

 Kepler in 1611 noted that snow-flakes are six-rayed, 



