Ice And Its Formation
( Originally Published 1907 )
"Down swept the chill wind from the mountain peak
WHEN in mid-winter, pond, lake, and river are covered with a glittering icy coat of mail, when the rushing babble of the little brook sounds strangely muffled and restrained because of its icy fetters, then we know that all nature is once more in the stern, iron grasp of winter, which brings with its piercing icy breath, great discomfort, as well as charm and exhilaration to all.
For who has not at some time in their lives revelled in the wonderful, joyous pleasures of skating? The ice crystal-clear beneath our polished steel, as we glided bird-like, swiftly over the polished, mirror-like pond beneath us. What exhilaration and glow we found in the fascinating sport. But how seldom, if ever, did we give a thought to the wonderful formation, and the beauties of that crystal surface beneath our flying feet, or did we dream that every bit of that ice was cemented and joined together in exquisite mosaic-like patterns, formed by countless millions of tiny ice flowers, far too delicate and small to be seen by the naked eye. This wonderful process of ice formation goes on, as Lowell so charmingly writes:
"All night by the white stars' frosty gleams
The conversion of liquid water through freezing into a solid crystalline state is certainly a most interesting process, as well as a mysterious one. There are many more difficulties to be encountered by crystal photographers in the study of ice formation, and its minute detail, than in that of either the snow or frost. Still many instructive and very interesting experiments have been made and facts obtained relating to the formation of the ice, and it has recently been possible to secure a valuable set of photographs which are wonderfully interesting, inasmuch as they serve to show the singular formation and development of ice crystal structure from start to finish.
Ice and water are so optically alike, that the formation of these ice crystals cannot be clearly detected without the aid of a microscope. These ethereal ice flowers are extremely frail and thin, less than one one-hundredth of an inch in thickness; and they vary from just a mere microscopic speck, to one-third of an inch or so in tabular diameter.
Generally every freezing body of water contains these beautiful ice crystals; myriads of tiny transparent ice flowers which assume distinct types and groups, more or less symmetrical. In order to watch the growth and development of these ice crystals which build up in such quantities on the surface of pond, river and brook, and which go, as a whole, to form solid ice, certain artificial conditions of light are necessary. These may be simply furnished by using a small mirror placed in a horizontal position beneath the surface of the water which is in process of freezing. Or, if one wishes to make an interesting study of the strange phenomena within doors, it may be quite possible to do so by simply placing water in a pail, and in the bottom of the pail, beneath the water, a mirror in a horizontal position. Of course the water should be kept in a cold room where it will freeze, or beneath an open window. The mirror affords the necessary white back-ground, and in this manner ice in process of freezing may be plainly viewed from its first germ growth to the finished ice crystal.
The process by which each water molecule, obedient to the great laws which govern nature, draws together in count-less numbers to form and build themselves into countless flower-like ice crystals, which go to form solid ice is a magical, fascinating process, well worth watching.
The types of ice crystals differ, however, upon still surfaces, to those which form upon running or disturbed water. Still, such a similarity exists in all ice crystal formation, and their habits of growth, that one may get a very clear idea of the process of their development by observing it in the simple manner above described.
Their different stages of growth is very clearly divided into five or six types of crystalline formation, and they pass from beginning to end, through the various stages of development as the nuclear, or smooth-edged crystal, the scalloped, the ray-like and the branching stages of growth; after which they loose their individuality by becoming solidified and merged into the solid ice form.
When the ice flowers or crystals first begin to appear, it is usually upon the surface of the water, and close to the sides of the pail. Frequently they push out in long, delicate,' needle- or lance-like forms while upon the plain edges of these sharp lances, scallops and delicate serrations quickly follow. But the individual or flower type of crystals which grow and scatter themselves over the surface of the water, do not attach themselves to any object, but grow in a detached fashion, and are really the most interesting crystal for observation and study. These detached crystals following out the laws which govern also the frost and snow crystals from their first stage of development, form a simple, smooth-edged disc of very thin transparent ice, gradually merging into the same, hexagonal, flower-like pat-tern, which governs the frost and snow crystals, although during the first stages of their development they show no tendency to follow hexagonal outlines. The photo-graphed illustrations showing this type of ice crystal, from its start to finish were most of them taken from indoor observation.
Beginning with photograph No. 128, we have the germ or birth, showing the first stage which the ice crystal assumes in its formation. It is always seen as a round disc of very clear, thin ice.
No. 129 illustrates the second stage of growth in which the tiny serrations or scallops are just beginning to shoot out and form about the germ or disc. Frequently they remain in this stage of development for some time without further change, but when it is zero weather they quickly increase in growth, and soon begin to show clearly defined scallops as shown in photograph No. 130.
In Fig. 131, the ice crystal has at last be-un to assume definite form, and its hexagonal shape is more clearly defined; while in No. 132, we have the completed flower-like outline, and in Nos. 133 and 134. the finished ice flower with its air inclusions of light and shade perfected. This shows the entire process of growth of the commonest type of these ice crystals, after which process they lose their identity and merge into the solid ice film.
However, ice film growth is not wholly supported in this manner, for branches often form upon the under side of the ice film, and grow downward into the water, as shown in photograph No. 135, which is a section of ice with fern-like crystal-growth growing down into the water, thus aiding in growth and solidification. Each type of crystal, and there are five, represents some different characteristic growth—the long, narrow, needle type, the simple stars of six points, and the spherical or discoidal forms; also those resembling coral-like formations.
Photograph No. 136 shows how individual ice flowers hamper each other in growth; that the points reaching out into clear water grow and draw to themselves with greater freedom the water molecules, while the points intruded upon or crowded out by other crystals or flowers, cease to grow, and do not interfere with the growth of others.
Nos. 137 and 138 are still other forms of ice-growth, the needle-like, lance-like form which we may frequently observe pushing out from the banks of a small pond or brook. These needle-like forms of ice eventually acquire branches about their entire radius, which grow and merge, with other ice flowers of different types, into solid ice upon the surface of the water.
No. 139 shows this type of ice-crystal completed. These ice-crystals form and rise like magic in early winter, especially upon and around the new ice upon the edges of small brooks, and streams.
"Sometimes the roof no fretwork knew But silvery mosses that downward grew; Sometimes it was carved in sharp relief With quaint arabesques Of ice-fern leaf."
Another very interesting example of ice-growth and formation which we occasionally discover upon the window-panes, and which should not be confounded with the frost work etchings, as it is in reality a thin transparent ice film, which frequently assumes exquisite formations and patterns. In No. 141 a the coral-like branch is a beautiful example of this window-pane ice, while upon the same pane of glass in precisely the same temperature we find another type,, as 141b resembling somewhat the transparent wing of an insect. There are but two distinct types of the ice film etchings, and they are classified as the feather form and the arborescent types. It is presumed that the forming of types is largely governed by the varying thickness of the glass upon which the ice film is deposited, and to the presence or absence of minute frozen particles of ice beneath the film. The feather form seems to develop upon cooler positions of the glass, and where the water film is thinnest.
Nos. 142, 143, and 144 are all rare examples of window ice. No. 16 shows to perfection a greatly magnified section of the coral-like tracings in detail. This window-pane ice, unlike the frost etchings, is ;always transparent or opaque water ice.
The ice pictures form in rather an exclusive fashion, and two types never intrude upon each other's territory, although we often find both types upon one pane of glass, as shown in the photographed illustration Nos. 140 a and 140 b.
The ice films always begin to develop upon the colder portions of the glass first. Feathery plume-like designs form first upon shaded portions, and slowly follow the fading sunlight as it passes from one pane to another, until the entire window is often covered with these transparent ice pictures. During zero weather the feathery types thicken to an astonishing degree, more so than the opposite type, or borescent ice film.
Another type of ice formation, and an interesting one, which in the photograph resembles somewhat a vegetable root or growth, is a form of ice which develops and grows upon and under peaty soil. These singular little ice columns rise as by magic, and form a miniature forest of tiny ice columns; frequently raising upon their tops the soil, stones, etc., to a height of many inches.
Nos. 145, 146 and 147, show photo-graphed examples of this type of columnar ice, No. 147 being a largely magnified section of one of these tiny columns in detail. Icicles are another interesting phenomenon belonging to ice study. They are evidently produced by the thawing of snow, and we frequently discover "freak" icicles hanging pendent from the house eaves during a thaw. They are, in a way, one of the many mysteries pertaining, and to be classed as ice crystallisations, and are closely related to the wonderful stalactite formations found in deep caves.
Beautiful beyond powers of description are the magical, fairy-like scenes which follow the passing of a great ice-storm. If you are out of doors just after such a storm, when the first rays of the sun begin to shine forth, lighting and touching every ice-sheathed twig with gold, and before the ice has begun to melt and fall from the trees, you can well imagine that you are catching a fleeting glimpse of fairyland! Trees that before the storm waved their leaf-stripped branches, bare and unlovely, in wailing symphony, tuned by the bleak wintry blast, have suddenly been clothed anew and made beautiful for a brief time, by their silvery coating of ice. Each tiny twig glitters and scintillates and crackles beneath the pale wintry sunshine; beautiful beyond words to picture.
These ice-storms occur more frequently in January, and are usually followed by a warm wave. They are seen in all their beauty in the New England States. Frequently after such an ice-storm there is a noticeable swelling and expansion of twigs and buds; the first suggestion of verdure and an early spring.
It is intended in this article but to touch upon the simple structural formation of the ice. There are still many important facts to discover, many interesting problems to solve. It would be interesting to know why the ice crystals which originate and have their being in the same body of water, and under precisely the same conditions of temperature vary so greatly in their structural formation.
Ice crystallisation in all its branches is a fascinating and wonderfully instructive study. It is still in its infancy, there is much as yet undiscovered material for experiment awaiting both the student and the camera specialist.
"Sometimes it was simply smooth and clear