A brief article on Snow-flakes, in one of the periodicals published
by the American Tract Society in the winter of 1862-3, accompanied by
a cut exhibiting some of their forms, elicited from its readers many
expressions of interest, and suggested the preparation of a book on
this curious but generally little-known subject.
The beautiful forms of many of the snow-crystals were observed and
sketched more than a century ago. The _Transactions of the Royal
Society of London_, for 1755, contain representations of ninety-one
varieties, with descriptions by Dr. Nettis. Captain William Scoresby,
the eminent English navigator, has given, in his _Arctic Regions_,
drawings of ninety-six varieties. More recently, numerous specimens,
with accompanying descriptions, have been given to the public by
James Glaisher, Esq., of Lewisham, England. It is from these sources,
chiefly, that the figures here exhibited have been derived.
It has been no part of our design, in this work, to enter into any
scientific statements concerning the snow-flakes, or the laws of their
formation. A brief general description of them is all that has been
attempted. Yet the reader should not, from this, infer that there is
any question respecting the truthfulness of the sketches. The drawings
were originally made with scientific precision, and have been carefully
copied. A few simple figures at the top of page 11 are designed to
show the primary geometrical _forms_ under which the snow-vapor
crystallizes. With that exception, they are all representations of
individual crystals, actually observed and sketched with the aid of the
microscope.
It is proper to add, however, that these representations are highly
magnified, especially those on the last two or three plates. The real
size of the crystals observed by Scoresby varied from one thirty-fifth
to one-third of an inch in diameter. Dr. Nettis remarks: “The natural
size of most of the shining, quadrangular particles, and of the little
stars of snow, as well the simple as the more compound ones, does
not exceed the twentieth part of an inch.” The dimensions as well
as form of the crystals seem to depend upon the amount of vapor in
the atmosphere, the temperature, and other circumstances not easy to
specify.
We may be permitted to express the hope that many of our readers will
examine for themselves these beautiful productions of nature. In our
own climate, the “treasures of the snow” are open to all who choose to
explore them; and there can scarcely be an amusement more entertaining,
and at the same time instructive, than that of observing and sketching
these delicate crystals. No expensive or complicated apparatus is
needed for this purpose. A good microscope is the chief requisite;
besides which, a pair of dividers and a rule will be sufficient. We
subjoin a statement from Mr. Glaisher of his own mode of making his
examinations.
“For the information of those who would carefully observe
snow-crystals, I may remark that my own plan of procedure is to expose
a thick surface of plate-glass on the outer side of the window, resting
on the ledge. Seated within the room, I am enabled, with comparative
comfort, and at my leisure, to make my drawings and record my
observations, the accuracy of which I am able to verify to my
satisfaction, as the crystal received upon the cold surface of the
glass, itself several degrees below freezing, remains a sufficient
length of time for the requirements of the observer. In many cases, it
becomes frozen to the glass, and is thus secured from the influence of
the wind, which not unfrequently snatches away some most intricate form
from the desiring eye of the observer.”
If this work shall be the means of introducing any of our readers to
the knowledge of this interesting department of the Creator’s works,
and eliciting those sentiments of admiration and reverence which his
wonder-working power should inspire in every beholder, it will not have
been issued in vain.