46 
THE SCIENCE OF A SNOW-FLAKE. 
By EGBERT HUNT, E.E.S. 
Thick clouds ascend ; in whose capacious womb 
A .vapoury deluge lies, to snow congealed. 
Heavy they roll their fleecy woi'ld along, 
And the sky saddens with the gather’d storm. 
T he poet of ^^ The Seasons^’ was a close observer of natural phe- 
nomena, and' no .one described more lucidly than Thomson 
did, the varying aspects of the year. But whenever the poet 
attempted the part of a natural philosopher he invariably failed. 
The lines quoted above are a fair example of that imperfect 
knowledge of science which Thomson possessed ; indeed they 
may be said to exemplify the kind, of information which was 
common amongst the educated classes at the commencement of 
the eighteenth century. . 
In the capacious womb of the clouds the vapoury deluge c?oes 
not lie to snow congealed, even in the utmost severity of a win- 
ter snow-storm. The retention of water-vapour in the air, and 
the condensation of it into clouds, or fog, or its precipitation as 
dew, rain, hail, snow, or hoar-frost, are processes very different 
from 'that which — -even with the .utmost practical license — can 
be understood by a vapoury deluge to snow congealed. The lines 
which follow are however so true to nature that they must be 
quoted as an example of beautiful descriptive poetry, well 
adapted to be the motto to the present essay : — 
. Through the hush’d air the whitening shower descends, 
At first thin wavering.; till at last the flakes 
Fall broad and white and fast, dimming the day 
With a continual flow. The cherish’d fields 
Put on their winter robe of purest white. 
It appears necessary, especially for the benefit of the younger 
class .of our readers, who may be induced to give a little 
.attention to the wonders of a snow-flake this - winter, that the 
conditions, as far as they are known, under which water is 
disseminated through, and held suspended in the air, should 
be examined. 
Around the Earth, like a great green serpent twining,” we 
