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Monday , 4 th February 1861. 
Principal FORBES, V.P., in the Chair. 
The following communications were read : — • 
1. Notes on the Snow Crystals observed during the late Frost. 
By Professor Allman. 
On the 26th of December last, about half-past 11 a.m., a light 
snow shower fell in Edinburgh, and lasted about half an hour. The 
air was at the time still, and the sky overcast with a thin haze, 
while the thermometer stood at many degrees below the freezing 
point. The appearance of the snow was very remarkable. It fell 
in loose open flakes, and lay upon the surrounding objects in little 
masses like tufts of exquisitely white, soft and light down. 
Remembering the descriptions of the crystals of snow in high 
arctic regions, and during intense frost even in our own latitudes, 
as given by Scoresby, Glaisher and others, I was desirous of deter- 
mining how far the structure of the snow now falling corresponded 
with the accounts of these observers. I accordingly, with the view 
of rendering their composition more apparent ly contrast with a dark 
surface, collected a few of the falling flakes upon a sheet of blackened 
pasteboard, when, even to the unassisted eye, a structure of marvel- 
lous beauty was at once revealed. The white down-like snow-flake 
was now seen to be an aggregate of symmetrical and transparent ice 
stars, many of them more than a quarter of an inch in diameter. 
When examined under the compound microscope with the aid of a 
two-inch object-glass, their beauty became still further enhanced, 
and it was then seen that every star was itself composed of a multi- 
tude of transparent crystals, in some cases tabular, in some acicular, 
and all grouped in obedience to a definite law, so as in their wonder- 
ful assemblages to give rise to shapes of exquisite symmetry, — shapes, 
too, of almost infinite variety ; the kaleidoscope, in its magical trans- 
formations, is not more rich in forms, — yet all pervaded by an un- 
broken unity, for their type had been already fixed ; and even in 
their most sportive mood, they could be seen to be under the con- 
