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forty or fifty yards in diameter. the middle of fields and Aoes. Now, such a number of these They often attain the height of pieces collected together in close thirty feet or upwards. contact, so that they cannot, from A calf, is a portion of ice which the top of the ship's mast, be seen has been depressed by the same over, are termed a pack.
maans as a hummock is elevated. When the collection of pieces It is kept down by some larger can be seen across, if it assume a mass; from beneath which, it circular or polygonal form, the shews itself on one side. I have name of patch is applied; and it is seen a calf so deep and broad, that called a stream when its shape is the ship sailed over it without more of an oblong, how narrow touching, when it might be obsoever it may be, provided the served on both sides of the vessel continuity of the pieces is pre- at the same time; this, however, served.
is attended with considerable Pieces of very large dimensions, danger, and necessity alone warbut smaller than fields, are called rants the experiment, as calves floes : thus, a field may be com have not unfrequently (by a ship's pared to a pack, and a floe to a touching them, or disturbing the patch, as regards their size and ex sea near them) been called from ternal form.
their sub-marine situation to the Small pieces which break off, surface, and with such an acceleand are separated from the larger rated velocity, as to stave the masses by the effect of attrition, planks and timbers of the ship, are called brasb-ice, and may be and in some instances, to reduce collected into streams or patches. the vessel to a wreck.
Ice is said to be loose or open, Any part of the upper superh. when the pieces are so far sepa- cies of a piece of ice, which comes rated as to allow a ship to sail to be immersed beneath the surfreely amongst them; this has face of the water, obtains the likewise been called drift-ice. name of a tongue.
A hummock is a protuberance A bight signifies a bay or sinu. raised upon any plane of ice above osity, on the border of any large the common level. It is frequent mass or body of ice. ly produced by pressure, where posed to be called bight from the one piece is squeezed upon ano low word bite, to take in, or enther, often set upon its edge, and trap; because, in this situation, in that position cemented by the ships are sometimes so caught by frost. Hummocks are likewise a change of wind, that the ice formed, by pieces of ice mutually cannot be cleared on either tack; crushing each other, the wreck and in some cases, a total loss has being coacervated upon one or been the consequence. both of thein. To hummocks, the ice is indebted for its variety Comparison of Ice frozen from Sea
Water and Rain-Water. of fanciful shapes, and its pictures que appearance. They occur When the sea freezes, the greatin great nunbers in heavy packs, est part of the salt it contains is on the edges and occasionally in deposited, and the frozen spongy
It is sup
mass probably contains no salt, in the progress of the freezing. but what is natural to the sea Thus it is, that in the coldest water filling its pores. Hence, weather, when a ship exposed to a the generality of ice affords fresh- tempestuous sea is washed with water, when dissolved. As, how- repeated sprays, and thereby coever, the ice frozen from sea vered with ice, that in different water does not appear so solid places obstructing the efflux of and transparent as that procured the water overboard, a portion from snow or rain-water, sailors always remains unfrozen, and distinguish it into two kinds, ac- which, on being tasted, is found 'cordingly as it seems to have been to contain salt highly concentratformed from one or the other. ed. This arises from the freezing
point of water falling in a certain Ice frozen from Sea-Water.
ratio according to the degree of
saltness; thus, though pure water, What is considered as salt- of specific gravity 1.0000, freeze water ice, is porous, white, and with a temperature of 329, water in a great measure opaque, (ex- of specific gravity 1.0263, concept when in very thin pieces), taining about 54 02. (avoird.) of yet transmits the rays of light salt in every gallon of 231 cuwith a greenish shade. It is bic inches, that is, with the desofter, and swims, lighter than gree of saltness common to the fresh-water ice, and when dissolve Greenland seas, freezes at 284. ed, produces water sometimes per- Sea-water concentrated by freezfectly fresh, and sometimes salt- ing, until it obtains the specific ish; this depends in a great mea- gravity of 1.1045, requires a temsure on the situation from whence perature of 13%, for its congelait is taken: such parts as are tion, having its freezing point reraised above the surface of the sea duced 1810 below that of pure in the form of hummocks, appear water ; and water saturated with to gain solidity by exposure to the sea-salt remains liquid, at a temsun and air, and are commonly perature of —40. fresh, whilst those pieces taken Thus, we are presented with a out of the sea are somewhat salt. natural process for extracting salt Although it is very probable, that from the sea, at least for greatly this retention of salt may arise facilitating that process in a confrom the sea-water contained in centration of the saline particles, its pores, yet I have never been by the agency of frost. able to obtain, from the water of When salt-water ice floats in the ocean, by experiment, an ice the sea at a freezing temperature, either compact, transparent, or the proportion above, to that befresh. That the sea-water has a low the surface, is as 1 to 4 neartendency to produce fresh ice, ly; and in fresh water, at the however, is proved from the con- freezing point, as 10 to 69, or 1 centration observed in a quantity to nearly. Hence, its specific exposed in an open vessel to a low gravity appears to be about 0.873. temperature, by the separation of Of this description is all young the salt from the crystals of ice, ice as it called, which forms a
considerable proportion of packed therefrom were so hot, that the and drift ice in general ; where it hand could not be kept longer in occurs in flat pieces commonly the focus, than for the space of covered with snow, of various di a few seconds. In the formation mensions, but seldom exceeding of these lenses, I roughed them fifty yards in diameter.
with a small axe, which cut the
ice tolerably smooth; I then scrapFresh-Water Ice.
ed them with a knife, and polished
them merely by the warmth of the Fresh-water ice, is distinguish- hand, supporting them during the ed by its black appearance when operation in a woollen glove. I floating in the sea, and its beau once procured a piece of the purest tiful green hue and transparency ice, so large, that a lens of sixwhen removed into the air. Large teen inches diameter was obtained pieces may occasionally be obtain- out of it ; unfortunately, however, ed, possessing a degree of purity the sun became obscured before it and transparency, equal to that of was completed, and never made the finest glass, or most beautiful its appearance again for a foricrystal; but generally, its trans- night, during which time, the air parency is interrupted by nume- being mild, the lens was spoiled. rous small globular or pear-shaped The most dense kind of ice, air-bubbles: these frequently forin which is perfectly transparent, is continuous lines intersecting the about one-tenth specifically lighter ice in a direction apparently per- than sea-water at a freezing tempendicular to its plane of forma- perature. Plunged into pure water, tion.
of temperature 32°, the proportion Fresh-water ice is fragile, but floating above to that below the hard ; the edges of a fractured surface, is as 1 to 15, and placed part are frequently so keen, as in boiling fresh water, it barely to inflict a wound like glass. The floats. Its specific gravity is about homogeneous and most transpa- 0.937. rent pieces, are capable of concen Fields, bergs, and other large trating the rays of the sun, so as masses, chiefly consist of this kind to produce a considerable intensity of ice. Brash-ice likewise affords of heat. With a lump of ice, of pieces of it, the surfaces of which by no means regular convexity, I are always found crowded with have frequently burnt wood, fired conchoidal excavations when taken gunpowder, melted lead, and lit out of the sea. the sailors' pipės, to their great astonishment; all of whom, who
On the Formation of Ice on the Sea. could procure the needful articles, eagerly flocked around me, for Some naturalists have been at the satisfaction of smoking a considerable pains to endeavour to pipe ignited by such extraordinary explain the phenomena of the promeans. Their astonishment was gressive formation of the ice in increased, on observing, that the high latitudes, and the derivation ice remained firm and pellucid, of the supply, which is annually whilst the solar rays emerging furnished, for replacing the great
quantities that are dissolved and sludge, and resembles snow when dissipated by the power of the cast into water that is too cold to waves, and the warmth of the dissolve it. This smootbs the climate into which it drifts. It ruffled sea, and produces an effect has frequently been urged, that like oil in stilling the breaking the vicinity of land is indispensable surface. These crystals soon unite, for its formation. Whether this and would form a continuous may be the case or not, the fol sheet, but, by the motion of the lowing facts may possibly deter- waves, they are broken into very mine.
small pieces, scarcely three inches I have noticed the process of in diameter. As they strengthen, freezing from the first appearance many of them coalesce, and form of crystals, until the ice had ub- a larger mass. The undulations tained a thickness of more than a of the sea still continuing, these foot, and did not find that the enlarged pieces strike each other land afforded any assistance or on every side, whereby they beeven shelter, which could not have come rounded, and their edges been dispensed with during the turned up, whence they obtain operation. It is true, that the the name of pancakes : several of land was the cause of the vacancy these again unite, and thereby or space free from ice, where this continue to increase, forming new ice was generated; the ice of larger pancakes, until they beolder formation had been driven come perhaps a foot in thickness, off by easterly winds, assisted per- and many yards in circumference. haps by a current; yet this new ice lay at the distance of twenty Freezing of the Sea in sheltered leagues from Spitzbergen. But I
Situations. have also seen ice grow to a consistence capable of stopping the When the sea is perfectly smooth, progress of a ship with a brisk the freezing process goes on more wind, even when exposed to the regularly, and perhaps more rawaves of the North Sea and West- pidly. The commencement is siern Ocean, on the south aspect of milar to that just described; it is the main body of the Greenland afterwards. continued by constant ice, in about the seventy-second additions to its under surface. degree of north latitude. In this During twenty-four hours keen situation, the process of freezing frost, it will have becoine two or is accomplished under peculiar three inches thick, and in less disadvantages. I shall attempt to than forty-eight hours time, capadescribe its progress from the ble of sustaining the weight of a commencement.
This is termed bay.ice,
whilst that of older formation is Freezing of the Ocean in a rough distinguished into light and heavy Sea.
ice; the former being from a foot
to about a yard in thickness, and The first appearance of ice the latter from about a yard upwhilst in the state of detached wards. crystals, is called by the sailors It is generally allowed, that all
that is necessary in low tempera These openings, therefore, may tures for the formation of ice, is be readily frozen over, whatever still water : here then, it is ob- be their extent, and the ice may tained. In every opening of the in time acquire all the characters ice at a distance from the sea, the of a massy field. water is always as smooth as that It must, however, be confessed, of a harbour; and as I have ob that from the density and transpaserved the growth of ice up to a rency of the ice of fields, and the foot in thickness in such a situ- purity of the water obtained thereation, during one month's frost, from, it is difficult to conceive the effect of many years we might that it could possess such characdeem to be sufficient for the for ters if frozen entirely from the mation of the most ponderous water of the ocean ;---particularly fields.
as young ice is generally found to There is no doubt, but a large be porous and opaque, and does quantity of ice is anrually gene- not afford a pure solution. The rated in the bays, and amidst the succeeding theory, therefore, is islands of Spitzbergen: which perhaps inore consonant to apbays, towards the end of summer, pearances; and although it may are commonly emptied of their not be established, has at least contents, from the thawing of the probability to recommend it. snow on the mountains causing a It appears from what has been current outwards. But this will advanced, that openings inust ocnot account for the immense fields casionally occur in the ice between which are so abundant in Green Spitzbergen and the Pole, ani land. These evidently come from that these openings will in all prothe northward, and have their bability, be again frozen over. origin between Spitzbergen and Allowing, therefore, a thin field the Pole.
or a field of bay-ice to be therein
formed, a superstructure may On the Generation of Fields.
probably be added by the followAs strong winds are known to ing process. The frost, which possess great influence in drifting constantly prevails during nine off the ice, where it meets with months of the year, relaxes tothe least resistance, may they not wards the end of June or the beform openings in the ice far to the ginning of July, whereby the conorth, as well as in latitudes within vering of snow, annually deposited our observation ? Notwithstand- to the depth of two or three feet ing the degree in which this cause on the ice, dissolves. Now, as may prevail is uncertain, yet of this field is supposed to arise this we are assured, that the ice on amidst the older and heavier ice, the west coast of Spitzbergen, has it may readily occupy the whole always a tendency to drift, and interval, and be cemented to the actually does advance in a surpris- old ice on every side ; whence the ing manner to the south or south- melted snow has no means of west; whence some vacancy must escape. Or, whatever be the assuredly be left in the place which means of its retention on the suis it formerly occupied.
face of the young field, whether