John Platts

CURIOSITIES RESPECTING ICE.

On the Greenland, or Polar Ice—On the Tremendous Concussion of Fields of Ice—Icebergs—Magnitude of Icebergs—The Glaciers—Shower of Ice—Remarkable Frosts.

Another poet thus describes the polar regions:—

The Greenland, or Polar Ice.

The following account of the Greenland, or Polar Ice, is abridged by the Editor of this work from a paper, by W. Scoresby, jun. M. W. S. published in The Memoirs of the Wernerian Natural-History Society:—“Greenland is a country where every object is strikingly singular, or highly magnificent. The atmosphere, the land, and the ocean, each exhibit remarkable or sublime appearances.

“With regard to the atmosphere, several peculiarities may be noticed, viz. its darkness of colour, and density; its frequent production of crystallized snow in a wonderful perfection and variety of form and texture; and its astonishingly sudden changes from calm to storm, from fair weather to foul, and vice versÂ.

“The land is of itself a sublime object; its stupendous mountains rising by steep acclivities from the very margin of the ocean to an immense height, terminating in rigid, conical, or pyramidical summits; its surface, contrasting its native protruding dark-coloured rocks, with its burden of purest snow;—the whole viewed, under the density of a gloomy sky, forms a picture impressive and grand.

“Of the inanimate productions of Greenland, none perhaps excites so much interest and astonishment in a stranger, as the ice, in its great abundance and variety. The stupendous masses known by the name of Ice Islands, Floating Mountains, or Icebergs, common to Davis’ Straits, and sometimes met with here, from their height, various forms, and the depth of water in which they ground, are calculated to strike the beholder with wonder: yet the fields of ice, more peculiar to Greenland, are not less astonishing. Their deficiency in elevation is sufficiently compensated by their amazing extent of surface. Some of them have been observed near 100 miles in length, and more than half that breadth; each consisting of a single sheet of ice, having its surface raised in general four or six feet above the level of the water, and its base depressed to the depth of nearly twenty feet beneath.”

The various kinds of Ice described.—“The ice in general is designated by a variety of appellations, distinguishing it according to the size or number of pieces, their form of aggregation, thickness, transparency, &c. I perhaps cannot better explain the terms in common acceptation amongst the whale-fishers, than by marking the disruption of a field. The thickest and strongest field cannot resist the power of a heavy swell; indeed, such are much less capable of bending without being dissevered, than the thinner ice, which is more pliable. When a field, by the set of the current, drives to the southward, and, being deserted by the loose ice, becomes exposed to the effects of a ground swell, it presently breaks into a great many pieces, few of which will exceed forty or fifty yards in diameter. Now, such a number of these pieces collected together in close contact, so that they cannot, from the top of the ship’s mast, be seen over, are termed a pack.“When the collection of pieces can be seen across, if it assume a circular or polygonal form, the name of patch is applied, and it is called a stream when its shape is more of an oblong, how narrow soever it may be, provided the continuity of the pieces is preserved.

“Pieces of very large dimensions, but smaller than fields, are denominated floes: thus, a field may be compared to a pack, and a floe to a patch, as far as regards their size and external form.

“Small pieces which break off, and are separated from the larger masses by the effect of attrition are called brash-ice, and may be collected into streams or patches.

“Ice is said to be loose or open, when the pieces are so far separated as to allow a ship to sail freely amongst them: this has likewise been called drift-ice.

“A hummock is a protuberance raised upon any plane of ice above the common level. It is frequently produced by pressure, where one piece is squeezed upon another, often set upon its edge, and in that position cemented by the frost. Hummocks are likewise formed by pieces of ice mutually crushing each other, the wreck being heaped upon one or both of them. To hummocks, the ice is indebted for its variety of fanciful shapes, and its picturesque appearance. They occur in great numbers in heavy packs, on the edges, and occasionally in the middle of, fields and floes. They often attain the height of thirty feet or upwards.

“A calf, is a portion of ice which has been depressed by the same means as a hummock is elevated. It is kept down by some larger mass, from beneath which it shews itself on one side. I have seen a calf so deep and broad, that the ship sailed over it without touching, when it might be observed on both sides of the vessel at the same time: this, however, is attended with considerable danger, and necessity alone warrants the experiment, as calves have not unfrequently (by a ship’s touching them, or disturbing the sea near them) been called from their submarine situation to the surface, and with such an accelerated velocity, as to stave the planks and timbers of the ship, and in some instances to reduce the vessel to a wreck.

“Any part of the upper superficies of a piece of ice, which comes to be immersed beneath the surface of the water, obtains the name of a tongue.

“A bight signifies a bay or sinuosity, on the border of any large mass or body of ice. It is supposed to be called bight, from the low word bite, to take in, or entrap; because, in this situation, ships are sometimes so caught by a change of wind, that the ice cannot be cleared on either tack; and in some cases, a total loss has been the consequence.”

On the Tremendous Concussions of Fields of Ice.—The occasional rapid motion of fields, with the strange effects produced on any opposing substance, exhibited by such immense bodies, is one of the most striking objects this country presents, and is certainly the most terrific. They not unfrequently acquire a rotary movement, whereby the circumference attains a velocity of several miles per hour. A field, thus in motion, coming in contact with another at rest, or, more especially, with a contrary direction of movement, produces a dreadful shock. The consequences of a body of more than ten thousand millions of tons in weight, meeting with resistance when in motion, may be better conceived than expressed! The weaker field is crushed with an awful noise; sometimes the destruction is mutual: pieces of huge dimensions and weight are not unfrequently piled upon the top, to the height of twenty or thirty feet, whilst doubtless a proportionate quantity is depressed beneath. The view of these stupendous effects, in safety, exhibits a picture sublimely grand; but where there is danger of being overwhelmed, terror and dismay must be the predominant feelings. The whale-fishers at all times require unremitting vigilance to secure their safety, but scarcely in any situation so much, as when navigating amidst those fields: in foggy weather, they are particularly dangerous, as their motions cannot then be distinctly observed. It may easily be imagined, that the strongest ship can no more withstand the shock of two fields, than a sheet of paper can stop a musket-ball. Numbers of vessels, since the establishment of the fishery, have been thus destroyed; some have been thrown upon the ice, some have had their hulls completely torn open, and others have been buried beneath the heaped fragments of the ice.

Icebergs.—“The term icebergs has commonly been applied to those immense bodies of ice situated on the land, ‘filling the valleys between the high mountains,’ and generally exhibiting a square perpendicular towards the sea. They recede backward inland to an extent never explored. Martin, Crantz, Phipps, and others, have described those wonders of nature, and all agree as to their manner of formation, in the congelation of the sleet and rains of summer, and of the accumulated snow, partly dissolved by the summer sun, which, on its decline, freezes to a transparent ice. They are as permanent as the rocks on which they rest: for although large portions may be frequently separated, yet the annual growth replaces the loss, and probably on the whole, produces a perpetual increase. I have seen those styled the Seven Icebergs, situated in the valleys of the north-west coast of Spitzbergen; their perpendicular front maybe about 300 feet in height, the green colour, and glistening surface of which, form a pleasing variety in prospect, with the magnificence of the encompassing snow-clad mountains, which, as they recede from the eye, seem to rise ‘crag above crag,’ in endless perspective.

ICEBERGS OF GREENLAND.—Page 526.

ICEBERGS OF SPITZBERGEN.—Page 528.

“Large pieces may be separated from those icebergs in the summer season, when they are particularly fragile, by their ponderous overhanging masses overcoming the force of cohesion; or otherwise, by the powerful expansion of the water, filling any excavation or deep-seated cavity, when its dimensions are enlarged by freezing, thereby exerting a tremendous force, and bursting the whole asunder.

“Pieces thus or otherwise detached, are hurled into the sea with a dreadful crash: if they are received into deep water, they are liable to be drifted off the land, and, under the form of ice-islands, or ice-mountains, they likewise still retain their parent name of icebergs. I much question, however, if all the floating bergs seen in the seas west of Old Greenland, thus derive their origin, their number being so great, and their dimensions so vast.”

Magnitude of Icebergs.—“If all the floating islands of ice thus proceed from disruptions of the icebergs generated on the land, how is it that so few are met with in Greenland, and those comparatively so diminutive, whilst Baffin’s Bay affords them so plentifully, and of such amazing size? The largest I ever saw in Greenland, was about 1000 yards in circumference, nearly square, of a regular flat surface, twenty feet above the level of the sea; and as it was composed of the most dense kind of ice, it must have been 150 or 160 feet in thickness, and in weight about 2,000,000 of tons. But masses have been repeatedly seen in Davis’ Straits, nearly two miles in length, and one-third as broad, whose rugged mountain summits were reared with various spires to the height of more than 100 feet, whilst their base must have reached to the depth of 150 yards beneath the surface of the sea. Others, again, have been observed, possessing an even surface of five or six square miles in area, elevated thirty yards above the sea, and fairly run aground in water of 90 or 100 fathoms in depth; the weight of which must have been upwards of two thousand millions of tons.”

The Glaciers.—Those vast piles of eternal ice with which it has pleased the Author of nature to crown the immense chasms between the summits of the Alps, are objects more grand, sublime, and terrific, than any others of the phenomena of nature which remain stationary. These tremendous spires and towers, of uncertain and brittle fabric, seem to forbid the attempts of travellers to explore the depth between them, or even the rocks and rich valleys around them; but courage and perseverance have been attended with commensurate success, and we are enabled by their labours to learn previously concealed wonders, and to reason upon the causes which produced them.

Mr. Bourrit, precentor of the cathedral church at Geneva, mentions, in the relation of his journey to the glaciers of Savoy, the enterprise of Messrs. Windham and Pocock, in 1741, who, inspired by the artless relations of the peasants, descriptive of the sublimity of their country, when they descended with honey and crystals for sale, determined to visit those frightful regions of ice which had received the appellation of Les Montagnes Maudites; or the Accursed Mountains. The gentlemen alluded to took every precaution for securing their safety; but entertaining many well-grounded fears, naturally arising from a first attempt, they did not reach any considerable distance beyond the edge of the ice in the valley of Montanvert, yet their example operated so powerfully as to induce several others to imitate them, and proceed to the boundary whence they returned: at length M. de Saussure had the resolution and courage to penetrate across the ice to the very extremities of the valleys; Mr. Coxe followed soon after: and from their publications every possible information may be obtained, of which the nature of the subject will admit.

The most astonishing phenomenon attending the glaciers, is their near approach to the usual vegetation of summer; for what can be more wonderful than to view wheat ready for the sickle, parched brown by the rays of the sun, and separated only by the intervention of a few feet, from the chilling influence of an endless bed of ice, which seems impenetrable to its rays.

Many systems and theories have been ingeniously suggested, to ascertain the first cause of the glaciers, their maintenance, and whether they increase or diminish in extent; of which, Gruner’s, improved and illustrated with actual observations by M. de Saussure, is the most rational and probable, and Mr. Coxe implicitly adopts it. Admitting that a person could be raised sufficiently above the summits of the Alps of Switzerland, Savoy, and Dauphiny, to comprehend the whole at one view, he would observe a vast chaos of mountains and valleys, with several parallel chains, the highest of which are situated in the centre, and the remainder gradually lessening as they retire from it. The central chain he would find to be surmounted by stupendous fragments of rock, towering in rude masses, which bear vast accumulations of snow and ice, where they are not decidedly perpendicular, or do not overhang their bases: on each side he would see the intervening chasms and gulfs, filled with ice, descending thence even into the verdant valleys, rich with foliage and cultivation. The inferior ranges of mountains, next the central, present the same appearance in a less degree; but in those more remote, the snow and ice are confined to the most elevated points; and others, still farther removed, are covered with grass and plants, which, in their turn, give place to such hills and valleys as are common in any part of the world.

Mr. Coxe divides the glaciers, in the above general survey, into two classes: the first occupy the deep valleys situated in the bosom of the Alps, and the second adhere to the sides and summits of the mountains. Those in the valleys are far more extensive than the upper glaciers; some are several leagues in length; and that of Des Bois is three miles broad and fifteen long: but they do not communicate with each other, and there are few parallel to the central chain; their upper extremities are connected with inaccessible precipices, and the lower proceed, as already mentioned, quite into the vales. The depth of these astonishing accumulations of frozen fluid vary from eighty to six hundred feet, and they generally rest on an inclined plane, where, urged forward by their own enormous weight, and but weakly supported by the pointed rocks inserted in their bases, they are universally intersected by yawning chasms, of dreadful aspect to the curious investigator, who beholds fanciful representations of walls, towers, and pyramids, on every side of him; but upon reaching those parts where the glacier rests upon an horizontal plane, his progress is seldom impeded by considerable fissures, and he walks in safety over a surface nearly uniform, and not so perfectly polished as that of ponds and rivers suddenly and violently frozen.

The absence of transparency, the various marks of air-bubbles, and the general roughness, so perfectly resemble the congelation of snow when half restored to fluidity, that M. de Saussure was immediately led to form the following probable theory of the formation of the glaciers. Snow is constantly accumulating in the recesses or depths of the mountains, during nine months of the year, by the usual fall of moisture, and the descent of vast masses, borne down by their weight, from the precipices and crags above. Part of this is necessarily reduced to water by slight thaws and casual rains, and, being frozen in this state, the glacier is composed of a porous opaque ice.

The upper glaciers Mr. Coxe subdivides into those which cover the summits, and those which extend along the sides of the Alps; the former originate from the snow frequently falling and congealing into a firm body, though not becoming actual ice, which the brilliancy of the projections has induced some philosophers to suppose it to be. M. de Saussure, having explored Mont Blanc, ascertained that the top was encrusted with ice, (which might be penetrated by a stick,) covering a mass of snow on the declivities, so chilled and dry as to be incapable of coherence.

The sides of the Alps support a congelation of half-dissolved snow, which is different from the pure snow of the summits, and the ice of the lower glaciers. Two causes operate to produce this effect; the first is the descent of water from the higher regions, where a dissolution of snow sometimes occurs; and the second arises from the more favourable situation of these parts for reflecting the rays of the sun, and the consequent melting of the snow. From hence downwards, the ice adhering to the cavities becomes gradually more solid by the freezing of the snow-water, then nearly divested of that air which in the less dissolved portions renders the ice, formed from it, porous, opaque, and full of bubbles.

An idea of the sublimity of the glaciers may be formed by reading the account of M. Bourrit, who appears to have viewed and described them with all that enthusiasm which such splendid objects must have inspired.—“To come at this collected mass of ice, (Des Bois,) we crossed the Arve, and travelling in a tolerable road, passed some villages or hamlets, whose inhabitants behaved with much politeness; they invited us to go in and rest ourselves, apologized for our reception, and offered us a taste of their honey. After amusing ourselves some time amongst them, we resumed our road, and entered a beautiful wood of lofty firs, inhabited by squirrels. The bottom is a fine sand, left there by the inundations of the Arveron; it is a very agreeable walk, and exhibits some extraordinary appearances. In proportion as we advanced into this wood, we observed the objects gradually to vanish from our sight; surprised at this circumstance, we were earnest to discover the cause, and our eyes sought in vain for satisfaction, till, having passed through it, the charm ceased. Judge of our astonishment, when we saw before us an enormous mass of ice, twenty times as large as the front of our cathedral of St. Peter, and so constructed, that we have only to change our situation to make it resemble whatever we please. It is a magnificent palace, cased over with the purest crystal; a majestic temple, ornamented with a portico; and columns of several shapes and colours; it has the appearance of a fortress, flanked with towers and bastions to the right and left; and at the bottom is a grotto, terminating in a dome of bold construction. This fairy dwelling, this enchanted residence, or cave of fancy, is the source of the Arveron, and of the gold which is found in the Arve. And if we add to all this rich variety, the ringing tinkling sound of water dropping from its sides, with the glittering refraction of the solar rays, whilst tints of the most lively green, blue, yellow, or violet, have the effect of different compartments in the several divisions of the grotto, the whole is so theatrically splendid, so completely picturesque, so great and beautiful beyond imagination, that I can hardly believe the art of man has ever yet produced, or ever will produce, a building so grand in its construction, or so varied in its ornaments. Desirous of surveying every side of this mass, we crossed the river about four hundred yards from its source, and, mounting upon the rocks and ice, approached the vault; but while we were attentively employed in viewing all its parts, astonished at the sportiveness of nature, we cast our eyes at one considerable member of the pile above us, which was most unaccountably supported, for it seemed to be held by almost nothing: our imprudence was too evident, and we hastened to retreat; yet scarcely had we stepped back thirty paces, before it broke off all at once with a prodigious noise, and tumbled, rolling to the very spot where we were standing just before.”

Shower of Ice.—A very uncommon kind of shower fell in the west of England, in December 1672, whereof we have various accounts in the Philos. Trans.—“This rain, as soon as it touched any thing above ground, as a bough or the like, immediately settled into ice; and, by multiplying and enlarging the icicles, broke every thing down by its weight. The rain that fell on the ground immediately became frozen, without sinking into the snow at all. It made an incredible destruction of trees, beyond any thing mentioned in history. Had it concluded with a gust of wind, (says a gentleman who was on the spot,) it might have been of terrible consequence. I weighed the sprig of an ash tree, of just three-quarters of a pound, the ice on which weighed sixteen pounds. Some were frightened with the noise in the air, till they discerned that it was the clatter of icy boughs, dashed against each other.”

Dr. Beale remarks, that there was no considerable frost observed on the ground during the above: whence he concludes, that a frost may be very intense and dangerous on the tops of some hills and plains; while at other places it keeps at two, three, or four feet distance above the ground, rivers, lakes, &c. and may wander about very furiously in some places, and be mild in others not far off. The frost was followed by glowing heats, and a wonderful forwardness of flowers and fruits.

We close this division with an account of Remarkable Frosts.—In the year 220, a frost in Britain lasted five months.—In 250, The Thames was frozen nine weeks.—291, Most rivers in Britain frozen six weeks.—359. Severe frost in Scotland for fourteen weeks.—508, The rivers in Britain frozen for two months.—558, Danube quite frozen over.—695, Thames frozen six weeks, and booths built on it.—759, Frost from Oct. 1 till Feb. 26 following.—827, Frost in England for nine weeks.—859, Carriages used on the Adriatic.—908, Most rivers in England frozen two months.—923, The Thames frozen thirteen weeks.—987, Frost lasted 130 days; begun Dec. 22.—998, Thames frozen five weeks.—1035, Severe frost on June 24: the corn and fruits destroyed.—1063, The Thames frozen fourteen weeks.—1076, Frost in England from Nov. till April.—1114, Several wooden bridges carried away by ice.—1205, Frost from Jan. 15 till March 22.—1407, Frost that lasted fifteen weeks.—1434, From Nov. 24 till Feb. 10, Thames frozen down to Gravesend.—1683, Frost for thirteen weeks.—1708-9, An extraordinary frost throughout the most parts of Europe, though scarcely felt in Scotland or Ireland.—1715, Severe frost for many weeks.—1739, One for nine weeks; begun Dec. 14.—1742, Severe frost for many weeks.—1747, Severe frost in Russia.—1754, Severe one in England.—1760, The same in Germany.—1776, The same in England.—1788, The Thames frozen below London bridge; and booths erected on it.—1795, The Zuyder Zee frozen over, and the rivers of Holland passed by the French.