Flake (ice)

“ Every larger flake retains on its surface the impression of the smaller flakes of which it is composed, so that when, by the discontinuance of the swell, the whole is permitted to freeze into an extensive sheet, it sometimes assumes the appearance of a pavement. But when the sea is perfectly smooth, the freezing process goes on more regularly, and probably more rapidly. During twenty-four hours’ keen frost, the ice will become an inch or two in thickness, and in less than forty-eight hours’ time capable of sustaining the weight of a man. ”

“ After a few preliminary efforts, I got down on to a curious flake of ice that had been split from the upper lip of the Schrund, and, carefully held by Collie and Hastings, examined its stability. The great flake appeared perfectly sound and secure, so the others came down on to it, and after careful inspection agreed that if we could reach a small notch in the edge of the ice flake some distance to our right and some twenty feet below our present standing ground, the last man could lower the two others and then jump across the chasm on to some convenient snow. ”

“ The air is made warmer when snow-flakes begin to form, and the temperature is higher than it would otherwise be while snowing continues. In this way the formation of ice and snow modifies and softens the temperature of arctic winters; and the blossoms which open with the spring-time are not more significant of milder airs than are those which are born of frost and vapor, and expand their petals to the winter's tempest. Snowflakes are stellate in form; the molecules of vapor in crystallizing aggregate in six-rayed figures, but in endless diversity of patterns. ”

“ Beginning its descent to the earth in a snowflake, the little mass falls slowly, so that when it comes against the earth the blow which it strikes is so slight that it does no effective work. In the state of snow, even in the separate flakes, the frozen water contains a relatively large amount of air. It is this air indeed, which, by dividing the ice into many flakes that reflect the light, gives it the white colour. This important point can be demonstrated by breaking transparent ice into small bits, when we perceive that it has the hue of snow. ”

“ Where the parts do not fit closely there is, of course, open water, which freezes over, in a few hours after giving off volumes of “frost-smoke.” In obedience to renewed pressure this young ice “rafts,” so forming double thicknesses of a toffee-like consistency. Again the opposing edges of heavy floes rear up in slow and almost silent conflict, till high “hedgerows” are formed round each part of the puzzle. At the junction of several floes chaotic areas of piled-up blocks and masses of ice are formed. ”

“ The grains of gray salt which are formed from sea water affect the figure, or at least the angle, of the cube; and in the congelations of other salts, and in that of sugar, there are found other solid angles with perfectly flat faces. Small snowflakes almost always fall in little stars with 6 points, and sometimes in hexagons with straight sides. And I have often observed, in water which is beginning to freeze, a kind of flat and thin foliage of ice, the middle ray of which throws out branches inclined at an angle of 60 degrees. ”

“ The ice once formed in such cavities, only melts slowly; for one knows that ice in melting, absorbs 60° of heat; and where find this heat in an air always very cold and nearly still? During a great cold, the ice forms with great promptness, while it melts with much slowness, even when the temperature of the air is several degrees above zero; what must then not be this slowness when the temperature of the interior air only rises in summer one degree above freezing point. It would need several summers to melt this ice if it did not reform each winter. ”

“ Standing on our little deck, and looking out on the floe, we had the strange spectacle of an undulating solidity, a propagated wave borne in swell-like ridges, as if our ice was a carpet shaken by Titans. I can not convey the effect of this sublime spectacle. The ice, broken into polyhedric masses, gave at a few hundred yards no indications to the eye of the lines of separation; besides which, the infiltration of salt water had no doubt increased the plasticity of the material. ”

“ Daily the sun got lower; so did the mercury in the thermometer; and often for days there was no sight of the former because of flying snow and the deep haze of frost-fog. The ice set more and more firmly about the Bowhead, and the pack which ground and crushed against the edge of the shore ice outside the headland no longer made any answering movement in the frozen stretch about her. The winter was upon them, and there were times when their ice igloo was put to severe tests as a frost defender. ”

“ We have butted several times against projecting floes, but it is as unmoved as solid rock. Very foggy: Rescue not visible. Thermometer at 29 degrees.
“We recognize, among the floe fragments around us, old play-fellows. Here we played foot-ball; there we skated; by this hummock crag stood my thermometers; and here I shot a bear. We are passing slowly from them, or they from us. Now and then a rubbish pile will show itself, cresting the pure ice. Even an old champagne basket, full of nothing but sadly-pleasant associations, is recognized upon a distant floe. ”

“ This broken-up ice is known as "Pack ice." During the breaking up of the ice, the floes crush together and their edges are broken and curled and piled with the pressure. Farther away from the open sea, well in among the solid floes, this pressure is very heavy and one floe may run over and another under the other. The edges of an extended crack, that has formed in a weak place, curl over and over and a long ridge of broken-up ice is the result. ”

“ The primary material of glacier-ice is the snow which falls in the high regions of the mountain. The yearly addition of snow in the higher cold regions gradually forces the snow down the valley; here, subject to alternate thawing and freezing, it undergoes a second crystallization into what is called névé snow, and still farther down, under increased pressure, comes transformed into a granular, opaque, bulbous ice, called névé ice, which at last changes into the compact blue ice of the glacier proper. ”

“ Air exposed to cold is condensed and made heavier; it will then gravitate to lower levels. The capacity of air for absorbing and retaining moisture varies with its temperature. Warm air will sustain a considerable amount of vapor, which will be condensed and precipitated if the air is cooled. As water is cooled and brought to the freezing point it expels a large part of the heat gathered at a higher temperature. As ice is melted to water this process is reversed, and heat and air are reabsorbed. ”

“ The rate at which ice is formed decreases as the thickness of the floe increases, and it ceases to be formed as soon as the floe becomes a non-conductor of the temperature of [4] the air by the increase of its mass, or when the driving of the ice-tables one over the other, or the enormous and constantly accumulating covering of snow, places limits to the penetration of the cold. ”

“ The leakage takes place, if not along cracks, through capillary channels, which are everywhere present in sea-ice.
It is interesting to note the temperature gradually rise during the descent. At the surface the ice is chilled to the air-temperature, say -10 degrees F., and it rises in a steep gradient to approximately 28 degrees F.; close to the freezing-point of sea water. The sea-ice in the boat-harbour varied in thickness during the winter between five and seven feet.
In contrast with sea-ice, the ice of a glacier is a marvel of prismatic colour and glassy brilliance. ”

“ In the deeps of rivers the same cooling below the freezing-point takes place without congelation, but as soon as this water reaches the stream below, the agitation immediately converts a portion of it into ice, which collects round the large stones at the bottom in the same way that crystallization commences in a solution of salt or sugar around a piece of thread or other substance which may be suspended in it. If a severe frost is followed by a bright day, thousands of these detached pieces of spongy ice may be seen rising from the stones which have served as nuclei for them ”

“ That evaporation which is steadily going on from the surface of ice even in the coldest weather, the crystals passing to vapor without the intervening stage of water, had worn off the embossing. The ice instead of being black was gray with countless air bubbles all through its texture. You will always find these after a day’s clear sun on a first freezing. I fancy the ice crystals make minute burning glasses under the sun’s rays and thus cause tiny meltings within its own bulk, the steam of the fusing making the bubbles ”

“ In order to melt one cubic foot of ice, as much heat is required as would heat a cubic foot of water from the freezing point to 176° F., or two cubic feet to 88° F. To melt a layer of ice a foot thick will therefore use up as much heat as would raise a layer of ice-cold water two feet thick to the temperature of 88° F.; and the effect becomes still more easily understood if we estimate it as applied to air, for to melt a layer of ice only 11⁄2 inches thick would require as much heat as would raise a stratum of air 800 feet thick from the freezing point to the tropical heat of 88° F.! ”

“ Sometimes when those floating pieces or plates meet with any obstruction in the channel of the river, they accumulate in such quantities as to cover the surface of the water, and become frozen together in one large sheet, but this kind of ice may be always readily distinguished from that produced in the usual way by the action of the cold air on the surface, which is smooth, transparent, and of an uniform texture ”

“ The strong floe of ice-table under ice-table, and hummock upon hummock, makes our position one of nearly complete solidity. We are glued up in ice; and to liberate us, some fearful disruption must take place. Twenty-five feet of solid ice is no feeble matrix, for a brig drawing but ten. Yet the water is wider, and still widening around us; so that now we hold on—that is, our floe holds on, to the great mass to the north of us, like a little peninsular cape.
“To the south every thing is in drifting motion—water, sludge, frost-smoke—but no seals. ”

“ The origin of the shelf ice is believed to be a sea-ice which because not easily detached at the time of the spring “break-up” is thickened in succeeding seasons chiefly by the deposition of precipitated and drifted snow upon its surface, so that it is bowed down under the weight and sunk to greater and greater depths in the water. To some extent, also, it is fed upon its inner margin by overflow of glacier ice from the inland ice masses. ”

“ No bird with a well-regulated mind would possibly trust himself out in this temperature.”
On the debit side, the temperatures reached unbelievable depths. 57° below zero was recorded by our thermometers (the spirit ones, for the mercurial bulbs froze solidly at around -40°) . The pack ice reached thicknesses of thirty-five and forty feet below the water where underrunning floes, freezing together, consolidated into a kind of glacial layer cake. ”

“ In the course of a tramp to-day about noon, the thermometer standing at -18°, I came across a wonderful instance of the yielding elasticity of ice under intense pressure. About two hundred yards from the brig, on her starboard quarter, was an unbroken plain of level ice, which before our recent break-up used to form one of my daily walks. It measured one hundred and thirty paces in its longer diameter and eighty-five in its shorter, and its thickness I ascertained this morning was over five feet. ”

“ During the summer the floe-ice decreases again by melting partly on the surface owing to the direct radiation of heat from the sun, partly on the under side owing to the higher temperature of the water in which it floats. The first kind of melting is that which prevails in the North Polar Basin, which the second occurs in more southern latitudes. The floe-ice is constantly more or less in movement, carried by winds and currents. The changing wind, and also to a great extent the changing tidal current, causes diverging movements in the ice by breaking it into larger or smaller floes. ”

“ Blizzard. A high wind at a low temperature, accompanied by drifting, not necessarily falling snow. Floe or Floe-ice. The comparatively flat, frozen surface of the sea intersected by cracks and leads (channels of open water) . Pack or Pack-ice is a field of loose ice originating in the main from broken floe, to which may be added material from the disintegration of bergs, and bergs themselves. Brash or Brash-ice. Small, floating fragments of ice—the debris of larger pieces—usually observed bordering a tract of pack-ice. ”

“ As long as the transformation of snow into ice is not complete, a rise of its temperature to 32° Fahrenheit, accompanied with thawing, reduces it at once again to the condition of loose grains of névé; but when more compact, it always presents the aspect of a mass composed of angular fragments, wedged and dove-tailed together, and separated by capillary fissures, the flattened air-bubbles trending in the same direction in each fragment, but varying in their trend from one fragment to another. ”

“ The crackling sound so commonly heard along the outer edge of the ice exposed to the action of the waves, is a consequence of the penetration of its pores by the sea-water, which is then immediately frozen, and disruption follows at once. But disruption on a far grander scale is due to a cause the very opposite of this, the sudden contraction and splitting of the ice, even in the great ice-fields, which is produced usually in winter by the sudden fall of the temperature. ”