ing and
snow was on the ground, the expanding bud, in close proximity to the
surface, gave out sufficient caloric or warmth to generate vapor from
the moist soil. This vapor rising around the stem of the plant, and
attracted by it, becomes congealed into what we term hoar-frost, in
numerous forms; some like shellwork, others like tulips, with radiated
petals, variously contorted, and often as symmetrical as snowflake
crystals.

[Illustration: Root-bud and frost-flower of the Cunila Mariana
(Maryland Dittany). A, the developing or budding root. B, the old stem
of the previous year. C, the congealed vapor or hoarfrost, forming the
first flower of various shapes.]

That plants in germinating have the power of generating heat was
proved by Mr. Hunter and by Lamarck. Experiments of Hales and Du Hamel
show that vegetation is not wholly suspended, however cold it may be;
and that there is a regular and gradual progress till the returning
warmth of spring gives a greater degree of velocity to the juices,
rendering their development more vigorous and apparent. If the
crystallization takes place when the air is calm, the crystals will be
regularly formed; otherwise, when windy, I have seen them like a shell
within a shell, very thin, of a pearly whiteness. Professor Tyndall
has shown in a very beautiful manner that ice is but an agglomeration
of snow crystals: the transparency of the former being due to the
expulsion of the air, entrapped in and causing the whiteness and
opacity of the latter. There is a formation called the snow plant of
California, which arises to some height, and has been compared to
various things, a fountain convoluted and enlarged above, a
crystallized small bushy shrub, etc.; but on closer inquiry, I have
failed as yet to get any definite ideas to its true character. Some
bulbs in the soil might cause such formations by the congelation of
vapor deposited successively upon itself, or the stems of the previous
year's growth yet remaining, and thus give them a sheathing of
frosting.

The shape of a star is common in snow crystals, which we all know
assume the most beautiful forms, and which are illustrated in various
publications. The eminent botanist Count Swinoskoff should give us
some clue as to the genus or character of the plant, the flower of
which, we are told, melted away on being touched, and as to the
stamens, the diamond seeds like a pin's head, etc. The whole needs
further explanation.

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