were somewhat uniform in structure, yet suggested a variety of natural objects, as feather-mosses, birds' feathers, and the most delicate lace-corals, but the predominant analogy was with ferns.
Yet they seemed to assume a sort of fantastic kindred with the objects to which they adhered: thus, on the leaves of spruce-trees and on delicate lichens they seemed like reduplications of the original growth, and they made the broad, flat leaves of the arbor-vitae fully twice as wide as before.
But this fringe was always on one side only, except when gathered upon dangling fragments of spider's web, or bits of stray thread: these they entirely encircled, probably because these objects had twirled in the light wind while the crystals were forming.
Singular disguises were produced: a bit of ragged rope appeared a piece of twisted lace-work; a knot-hole in a board was adorned with a deep antechamber of snowy wreaths; and the frozen body of a hairy caterpillar became its own well-plumed hearse.
The most peculiar circumstance was the fact that single flakes never showed any regular crystallization: the magic was in the combination; the under sides of rails and boards exhibited it as unequivocally as the upper sides, indicating that the phenomenon was created in the lower atmosphere, and was more akin to frost than snow; and yet the largest snow-banks were composed of nothing else, and seemed like heaps of blanched iron-filings.
Interesting observations have been made on the relations between ice and snow.
The difference seems to lie only in the more or less compacted arrangement of the frozen particles.
Water and air, each being transparent when separate, become opaque when intimately mingled, the reason being that the inequalities of refraction break up and scatter every ray of light.
Thus, clouds cast a shadow; so does steam; so does foam: and the same elements take a still denser texture when combined as snow.
Every snow-flake is permeated with minute airy chambers, among which the light is bewildered and lost; while from perfectly hard and transparent ice every trace of air disappears, and the transmission of light is unbroken.
Yet that same ice becomes white and opaque when pulverized, its fragments being then intermingled with air again.—just as colorless glass may be crushed into white powder.
On the other hand, Professor Tyndall
has converted slabs of snow to ice by regular pressure, and has shown that every Alpine
glacier begins as a snow-drift at its summit, and ends in a transparent ice-cavern below.
‘The blue blocks which span the sources of the Arveiron were once powdery snow upon the slopes of the Col du Geant
The varied and wonderful shapes assumed by snow and ice have been best portrayed, perhaps, by Dr. Kane
in his two works; but their resources of color have been so explored by no one as by this same favored Professor Tyndall
, among his Alps
It appears that the tints which in temperate regions are seen feebly and occasionally, in hollows or