Polar Exploration/Chapter 4

by William Spiers Bruce

 

 

CHAPTER IV

 

SEA ICE AND COLORATION OF ICE AND SNOW

 

At almost any time during even a summer cruise, when there is a perfect calm and when the sun is low during the night, there may be found under the shadow of loose pieces of ice, which gently rest upon a glassy sea, newly-formed fine ice spicules floating on the surface: these ice spicules are dissipated when the rays of the sun play once more on the surface of the water. If the temperature of the water be taken at such a time it will be found to be about 29° F., which is therefore clearly about the temperature at which the polar seas begin to freeze. That is to say, about 3° F., below the freezing-point of fresh water, which, as the reader will know, freezes at 32° F.

Now, if the temperature of the air falls considerably below 28° F., say to 15° F., these ice spicules or crystals increase very rapidly, and the whole surface of the sea becomes covered with a considerable layer of them, which is known by polar seamen as "Bay ice." If there is a snow shower the snow mixes with these crystals and does not melt, but becomes part and parcel of this bay ice and is termed "slush." This may increase in thickness up to, say, 3 or 4 inches. If wind arises and sea is thrown into waves, it is found that the crystals are all separate and that the bay ice or slush is quite mobile, but it is not so mobile as the water without crystals, the shape of the waves being less sharp. In fact, the waves have an oily motion in a slush-covered sea. If one tries to pull in a boat, the pulling is found to be very heavy, and even the way of a large ship with good steam power is seriously impeded. The water is, in fact, "gluey." The "slush" may include in it any small fragments of ice that are floating on the sea at the time. Should there be a sudden lowering of the air-temperature with a heavy fall of snow, then the slush is formed in greater part of snow crystals, but has essentially the same qualities, except that it may be slightly more disintegrated than simple bay ice.

If the weather is stormy and the water is considerably disturbed, though the slush increases considerably the spicules of ice and snow are evidently more or less free, though the water continues to become more and more gluey and waves become less and less pronounced: but, if it is calm weather, the crystals become entangled in somewhat fixed positions, and adhering to each other the slush becomes a plastic crust on the surface, even less than an inch thick. This newly-formed sheet of ice is known as "Bay ice," because naturally it forms more easily in sheltered bays. Any new ice, from the thinnest film to ice of, say, 6 to 8 inches in thickness, is termed "Bay ice." An ordinary wooden ice ship forges its way through it by continuously steaming ahead. Until this bay ice is some 4 or 5 inches thick it has a black appearance, being more or less translucent. But when it becomes thicker and more securely frozen together with some sharp frost it becomes whiter.

A ship steaming through "Black ice" cuts through it as through a sticky scum, leaving a blacker lane of water astern, exactly the width of the ship, which does not close up until frozen over again. But through the thicker and more rigid "White ice" as the ship steams ahead a long split is formed ahead of her, through which she is able to forge her way. This more completely formed white ice is often easier for navigating a ship through, because it is more brittle than the thinner black ice, which is gluey in texture.

Now, if the water remain calm very striking and beautiful developments occur. There is always some horizontal motion in the surface of the sea, even if it is a glassy calm, owing to currents or change of tide or other causes. For one of these reasons, the surface water spreads itself out by flowing away from one position a little more rapidly than the surface water at its rear is making up upon it, possibly on account of the dividing of the tides or a slight air blowing in a contrary direction in one quarter to that in the other; or it may be due to one of those delicate air-currents that one sees looking over a glassy Scottish loch, which by mere chance enables one fairy yacht to move ahead of its becalmed fellows not many hundred yards distant. Then the crust divides into thousands of hexagonal discs from about an inch to several feet in diameter, the diameter increasing with the thickness of the bay ice; in between the discs, the shiny black lines of water broaden into wide lanes, and the surface of the sea is like a patchwork quilt. Now, some slight disturbance occurs, a little wind or tide, which causes the surface waters to come together again, the more or less hexagonal ice discs hustle together, their delicate sides and corners are crushed and broken, and are curled up by the pressure. Thus they become subangular discs, each with a flat interior and a bruised turned-up edge, like a pancake. Again the motion of the surface of the water, due as often as not to tide, separates these discs; again they are hustled together and bruised and get their edges still more turned up. This goes on continually, and meanwhile the discs are thickening and solidifying with the continued low temperature. This ice is known as "Pancake ice."

By continued and increased frost the edges of the pancakes get frozen together and the whole surface of the sea has a continuous sheet of ice, only to be broken up again, however, into fresh though larger hexagons, which in turn are hustled together and form magnified pancakes many feet in diameter. These require greater force, as they increase in thickness and solidity, to break up again, until eventually they remain together in one great solid sheet which nothing but a heavy gale and a tremendous sea will break into pieces. Those great sheets of ice, often many miles—it may be even hundreds of miles—in extent, are known in general terms as "Floes," or "Field ice," "Floe ice" usually being employed when they are less extensive, the term "Field ice" for ice that stretches unbroken beyond the limits of the eye from the crow's-nest.

A "Land floe" is a floe that is formed next the land and that remains fast to the land, if the weather is light, during, it may be, the whole of the following summer. Such a floe continues to increase in thickness during the second winter, but it is unlikely that the weather will be so favourable as to allow this "land floe" to survive a second summer. But, on the other hand, the first year's floe may rot away entirely during the first summer after its formation. I saw this happen in Franz Josef Land during the summer of 1897 to a land floe that I had watched from its birth to its disintegration, from the time the first "bay ice" was forming on the calm surface, through the period when the ice was thick and solid, until it had rotted entirely away.

The surface of such a primitive floe is as level as the surface of the sea, and before the winter snows and the drift from the land or other parts of the same floe cover it, it has the texture of a good Brussels carpet on the surface. It is never smooth or glassy like the ice formed on the surface of fresh water. One cannot curl, slide, or skate upon it. Ski stick on it and sledges will not glide over it. The surface is sticky, and even at low temperatures it wets through the thin soles of fur boots and proves very destructive to them. It has a sort of efflorescent appearance and a saltish taste. It is, in fact, the saltest layer of the floe, which may freeze to a thickness of 5 or 6 feet; sometimes less thick when strong currents flow under its surface, sometimes of greater thickness in sheltered lochs and bays. But while the surface of the floe is very salt, if a piece of ice be taken out of any intermediate part it is found to be relatively fresh, certainly not nearly so salt as the sea itself.

I shall return later on to this interesting question of the saltness of sea ice, at present I wish to deal only with general naked-eye structure. It can be seen that this ice is much more plastic than fresh-water ice. Fresh-water ice is relatively brittle, even in thin layers. Fresh-water ice, of the thickness of about 2½ or 3 inches, will bear the weight of a man, but a child's foot would sink through sea ice of similar thickness, as if going through a layer of tough glue. You can push a stick through it, and a seal can push his nose and head through from below to get a breath.

Now, if there be a slightly undulating swell running under this new ice one sees the ice following the same motion, but to a less marked degree. But the thicker and more solid the ice, the more resistance is offered, until there comes a point where the sea-swell is killed. On the other hand, if the motion of the sea be more violent the more solid fields and floes are strained to breaking-point, and split up, first into small floes of a mile or two or at least several hundreds of feet in diameter, and these in their turn being repeatedly strained, twisted, and hurled in the wild confusion of the storm against each other, against bergs or against a rocky shore, get broken up into thousands of pieces only a few feet in diameter. 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. These ridges are known as "Pressure ridges," and the irregular piles of ice of which they are formed, or similar piles of ice formed along the edges of smaller free-floating floes, or the piles of ice that are formed by the pieces of pack ice that get heaped upon each other are known as "Hummocky ice" or simply "Hummocks."

This irregular conglomeration freezes together again almost immediately if it is winter, and indeed it needs very tempestuous sea and weather conditions to break up the solid continuous floe in winter. The usual time of break-up is in the spring, when with rising temperatures the sea ice is becoming rotten.

"Brash ice" is ice that is usually met with on the outskirts of the pack. It is the remnant of the fray, being composed of a chaotic collection of small subangular pieces from a few feet in diameter to an inch or two, which have been broken off all kinds of larger pieces during their battle with the wind and sea and with one another.

In the autumn, especially with the increasingly stormy weather, the pack ice is jammed up together. Irregular pieces of all sizes and shapes are huddled together: fragments of the new floe of the previous year, fragments of hummocky ice, fragments of ice that have been thickened by the frosts of two or three winters, fragments of over-ridden floes, bergy bits broken off icebergs, and brash ice. All this ice, each piece different from its neighbour, is driven together by the wind and sea, and is formed into "streams" of ice, which always lie at right angles to the wind and which may be many miles in length. Loose pieces of ice in the open sea, on the weather side of these "streams," are driven before the wind more quickly than the stream itself, and are ultimately driven into the stream and form part of it. Pieces on the lee side, however, do not readily get driven off, as they are protected from wind and sea by the whole breadth of the stream, thus the stream increases in size. The stream which lies farthest to windward drives faster and is driven on to the stream under its lee. Stream joins stream, and as the storm increases we have a formidable "body of ice" many miles in width as well as breadth. This pack drives on and on, resistless and all-conquering, until it is checked in its steady career by meeting another solid pack, or by the land, or, in the Antarctic, by one of those giant bergs. Confusion arises; the ice piles itself high up on the land—great heaps of even 20 or 30 feet high being formed. Here it may remain for many a year before it is finally dissipated. I have seen this occur more than once. If it is driven against the vertical cliff of an Antarctic berg or against the face of a barrier like the Ross Barrier, it will curl up the face of the cliff and fall back again upon itself in a confused heap. If a ship is between it and the land, the ship will be hurled ashore and no human effort can do anything to avert such a disaster. This has frequently happened. In recent times, the Alert was driven ashore with the pack at Rawlings Bay in Kennedy Channel, in 1876, and the Stella Polaris at Teplitz Bay, in Franz Josef Land, in 1899.

A ship may be lying against a floe, perhaps fastened to a land floe, when the pack drives down upon it and it is caught; or, more deadly still, between two floes, when the pack drives down upon the outer one, drives it on, and the ship is crushed to matchwood between the two, unless—as happened with the Scotia off Coats Land—she is so constructed that when the "nip" comes she rises to it, and is heaved out on the top of the ice, the floe and pack driving under her, leaving her high and dry, but safe and sound. Nothing can stop the oncoming pack except the land itself or a change of wind or tide. Sometimes the pack moves onwards even in fine weather; this means that there has been wind not very far off which has set the distant pack moving, its motion being transmitted to the entire body of ice.

With the lulling of wind comes a change. The ice which has been forced together opens up, lanes of calm water appear and smaller channels, till every piece of ice is more or less separated from its neighbour. The scene is altogether changed. As the white ice floats in the clear blue waters, one can scarcely realise that these same elements were not long since playing such a very different rôle. Now all this loose pack will with the advent of cold wintry weather be frozen together, the lanes of water will be covered once more with young or bay ice. Wind and weather may pack it closer together, the plastic new ice giving way with the old ice embedded in its matrix. The whole becomes a solid floe, and many floes unite and form great "fields" of ice. This field ice is more formidable than the fields and floes of new ice that are formed during a single winter, and which during the following summer are known by polar voyagers as "one-year ice." At the beginning of winter they may show a thickness of possibly five or perhaps ten feet, and in places there will be even thicker pieces. Then comes a whole winter's intense frost, snow falls and adds to the weight and thickness, and when this ice breaks up the following spring we have a really formidable pack to encounter. When such pack ice is not very open, but still open enough for a protected ship to work its way through, the ship has to be handled with the greatest care even when navigating through it in fine weather. This ice cannot be charged indiscriminately like one-year ice, and one must be able to distinguish between one piece of ice and another. This can only be done by one who has had many years of experience of polar ice-navigation.

One piece, a heavy-looking mass, may be charged and will be shattered; another, a wise ice-master will avoid charging because he knows it is of steely hardness and that his ship will make no impression upon it. A careful ice-master never touches a piece of ice if he can avoid doing so at any time, in spite of his stout ship, the full strength and power of which is needed when he is forced to work his way through tight ice and heavy ice, through which a novice would never dream a ship could pass. A good ice-master will nose his ship through ice that would seem to one without experience navigating amongst it absolutely impenetrable, and he will go through narrow lanes that are not as broad as the beam of his ship, first getting the starboard bow of the ship against an obstinate heavy piece and working it away in among its fellows and then pushing another piece similarly aside with the port bow. Then the ship is brought to a standstill with the engines going full speed, till bit by bit one sees a heavy floe beginning to rotate, and finally, by its motion and momentum, clearing a way, through which the good ship steams ahead. Now possibly comes a difficult place: two heavy floes have met at two points and there is open water beyond; screwing the ship is of no avail, the engines are stopped and reversed when the order of "go astern" is given. Then she charges full speed at the "neck of ice," and when the shock comes trembles from stem to stern, the mast and yards shake violently and the crew are almost thrown off their feet, but there is no visible effect on the ice. This operation is repeated a second and a third time, and the narrow neck of ice between the two floes shows signs of cracking. Once more astern! Once more full speed ahead! The ice shivers, the neck breaks, and the gallant ship is in the open water that she has fought so hard to reach.

But it may happen that the task is hopeless, that too much valuable coal would be spent to accomplish the breaking of such a neck between two floes, and in that case the ship retreats and goes round the end of the floe instead. Or, if that seems of no avail, the ice-anchor is dropped over the ship's bows and she is made fast to the floe. There she waits, the skipper takes a meal and perhaps a sleep while his trusted mates watch developments. A change of tide or wind, perhaps three or four hours later or perhaps twenty-four hours later, causes the ice to slacken, and, without any effort, the ship steams through what was only a short time before an impenetrable part of the pack. Long experience of ice, good judgment, cool-headedness, and indomitable patience are the leading qualities of a good ice-navigator.

In the Arctic Regions the floes and pack ice are essentially the same as in the Antarctic Regions, except that there is more snow on the floes, and consequently also on the pack, in the Antarctic Regions. In the Arctic Regions the snow on the floes is not only less, but is more consolidated and firm enough to walk upon; the snow is often very soft on the Antarctic floes. In the summer of 1892 and 1893, when cruising in Erebus and Terror Gulf, I sank to my knees when walking on the floes or pack, and the sealers often had hard work in dragging the skins of the slaughtered seals to the water's edge. The amount and softness of the snow doubtlessly vary in different years and different places, but there is, as a rule, more and softer snow on the floes in the south than in the north.

In summer it is warmer in the Arctic than the Antarctic, and the sun melts pools on the surface of the floes and pack. In this greater surface-melting the snow layer is diminished greatly during the summer months in the Arctic. I never met with pools of water on Antarctic pack ice, though such may occur. These pools of water on the ice in the Arctic Regions are in most cases composed of fresh water, so much so that when there is a considerable pool conveniently situated a whaler or exploring ship will fasten the ship on to the piece of pack or floe with her ice-anchors, and will, by means of the hose and pump, or by buckets, fill up the fresh-water tanks. This water makes perfect drinking water, far finer than can be got in any seaport. To know that there is always in readiness a perfect supply of the most excellent fresh water is one of the greatest boons to ships navigating in the Arctic Regions, and a luxury which is forbidden to ships navigating in other seas. In the Antarctic, since one seldom or never meets with such pools, one has to pick out a nice old hummocky piece of sea ice or a bergy bit that has been chipped off one of the great bergs, and take some boat-loads of this ice on board. The ice is put into large tubs or barrels, and steam is blown through. It rapidly melts, and is led away into the ship's tanks and makes most excellent water. There is no excuse for a ship having bad drinking water on board in the Polar Regions. Through the entire winter in Franz Josef Land in 1896 and 1897, at our encampment at Cape Flora, we had a huge barrel inside the house not far off from the stove. Every morning after breakfast, it was regularly filled with compact blocks of consolidated snow that were quarried out of neighbouring gullies. This snow kept melting all day and night, and there was thus a constant supply of good water available. But during the wintering of the Scottish National Antarctic Expedition, when the Scotia was frozen in Scotia Bay for eight months, sea ice was used for this purpose. A good old hummocky piece of ice would be selected by an officer, and then at seven o'clock every morning all hands would man two or three sledges, taking with them picks and ice-drills, and would bring several loads of beautifully clear blocks of ice back to the Scotia. A pile of this was made in a secure place on deck, and a large copper cauldron in the galley was continuously kept full of beautifully pure fresh water from the melting of this ice.

Be it specially noted that during the whole of this time we used sea ice for drinking, cooking and washing, and that fresh water was obtained from it with not the slightest taste of salt. The water was like "soft water"; when mixed with soap it made a good lather. Though it is interesting to note that when a delicate chemical test was performed with nitrate of silver, a slightly milky appearance showed itself in the water, demonstrating that there was actually an infinitely small amount of salt present, this was quite insufficient to be detected by taste. One very good criterion of the purity of this water was that it made excellent tea, and if anything is absolutely spoilt by the presence of salt, the subtle flavour of good tea suffers first. The absence of salt in ice that is formed from the freezing of salt water has been the subject of long and most important investigations by Mr. J. Y. Buchanan (Ice and its Natural History, Royal Institution, May 8, 1908), who has established that the crystals formed in freezing a non-saturated saline solution are pure ice, the salt from which they cannot be freed belonging to the adhering brine, and that the freezing-point of water is lowered by the presence of salt or other foreign matter dissolved in it. Thus it may be said that, in nature, ice never melts and water never freezes at exactly 32° F. The melting-point depends on the medium and on the pressure to which the ice is subjected. If the pressure is constant it varies with the nature of the medium; if the nature of the medium is constant it varies with the pressure.

The reader is now able to distinguish the different species of ice met with in polar seas. The chief fact to be noted is that, in these seas, we meet with two kinds of ice, the one having its origin in the sea and the other on the land or in the air. The former has the lower melting-point of the two and melts first. While it is melting it takes all the heat available and so preserves the fresh-water ice, which melts after all the salt-water ice is gone. In old hummocky ice this process of purification has been going on intermittently whenever the weather was warm enough. I trust I have made these matters plain, but it is impossible by words to give a true idea of the marvellous colour and beauty of the ice in polar seas, or of its irresistible power when driven hither and thither by sea and wind. There can be no more terrific experience than a storm in a living polar pack. No human power is of any avail in resisting the combined onslaught of wind, sea, and heavy ice.

Yet I know no scene more wonderful and more stimulating than one of those brilliant sunny days in fine weather in the pack either in the north or the south. The dazzling ice shines like brilliants in the sun. Seals and penguins on the ice bask in the sun or play around pieces of pack ice, in and out, and over and under "tongues," in the intensely clear and often intensely bright blue water. In the south small shrimplike creatures (Euphausia), and in the north the midget polar cod, can be seen darting about in and out of the honeycombed ice tongues projecting under water from almost every piece of pack ice, probably sustaining themselves on diatoms and other algæ that are there too, and which stain the pure ice with a rusty brown colour near the surface of the sea. Snowy petrels, cape pigeons, and Wilson's stormy petrel in the south, and ivory gulls, kittiwakes and burgomaster gulls in the north fly gaily in the blue sunlit sky, speckled with thin wisps and flakes of cirrus clouds. Penguins in the south and guillemots and puffins in the north dart like torpedoes in the narrow lanes of water, only coming to the surface for a breath. Every living thing seems bright and gay, stimulated by the brilliant conditions of the weather, which seems to throw crispness and life into the very ice itself, and makes the saddest think that there is joy in living.

Then the scene changes, as the sun, skirting the horizon, paints the white ice world with colour, with tints that are absolutely beyond conception if you have not seen them, and that no Ruskin can describe. These beautiful scenes so—soft and so delicate—produce impressions that can never be obliterated; different altogether from the effect produced by the brilliant scene described above. Soothing—not stimulating! Making one think of the world as kind and gentle, recalling the past, picturing the future. Making one think what a lonely unit one is in this world; making one compassionate and sympathetic to one's fellow men.

The cold grey scene depresses the spirit. The air is motionless, the sea of oily glassiness, and a dull whitish grey mantle of fog or mist hides everything from view, except the ship's deck and a few pieces of white ice near by, resting in dull grey water, fading away indefinitely in the mist. It is a time of inaction: there is no object to go in one direction or another: nothing can be seen ahead. Sometimes several days of this weather continue, causing forced inaction, and one feels as if the rest of one's life was to be spent in this cold grey mantle. But there is a thinning of the mist; a gleam of the hidden sun; and a fog-bow subtly spreads its fairy ring upon the evanescent mist, which folds itself up in rolls and vanishes, and once more there is a brilliant world of sparkling sunshine.

In the Antarctic Regions almost all the ice floating in the sea, whether land or sea ice, is covered at sea-level with a light wash of yellowish brown or yellow ochre. The bergs are coloured by it as well as the pack ice, where the ice is lapped by the sea. When a ship charges against a piece of one-year pack ice, the ice is easily broken and often breaks not only vertically, but horizontally. The horizontal fracture occurs at about sea-level, and there is revealed a continuous layer of this ochreous ice. On examination it is found that the coloration is due to the presence of several species of diatoms, all actively living.

If the reader recalls the colour of a polar bear, he will know that the colour of its coat is yellow and not white. The coat varies, in fact, from being very nearly white at the end of winter and early spring when it is in its finest condition. The bear-hunters well know this, several times the price being obtained for a winter skin than for one at the end of summer, when it is actually brownish yellow. This yellowness is more marked when the bear is in his natural surroundings of white ice, and at first sight seems anything but a protective coloration. Yet when an old Arctic voyager shouts "A bear!" younger hands will look a while before they see the heavy monster a couple of hundred yards off on a floe, and it is not easy, at first, to account for this, until looking across the great expanse of white one sights another bear, and keeps on seeing imaginary bears for a long time. The old veteran smiles and simply says, "Yellow ice." Then the novice easily accounts for his wrong conclusion, and finds that there are patches of yellow ice all over the floe just the colour of a polar bear's coat, lighter in spring when daylight has just returned and when winter snows and frosts still hold, darker in summer like the bear's dirty summer coat. I remember an incident on board the Windward in 1896, in the Barents Sea. All hands were on the poop deck on a Sunday afternoon while the veteran mate was conducting a short service. Short as the service was, our mate appeared unduly anxious to get it over, until, with a final effort, he finished—for-ever-and-ever-Amen-there's-a-bear! The old boy had seen the bear shortly after the beginning of the reading till the animal was within a hundred yards of a congregation of twenty-five men, whose eyes, it must be confessed, wandered from the reader more than once, but not one of whom had seen the bear though he was in full view. The change of scene need not be described in this place, but before the bear was within thirty yards of the ship, he lay a victim to the devout mate and his congregation. Yellow ice was the explanation!

Now if some of this ice be collected and melted, a yellowish deposit is left, which on microscopic examination is found to be composed mainly of diatoms. These diatoms and other algæ spread themselves over the entire surface of Arctic sea ice, and the yellow patches indicate specially favourable growing-places for them. The distribution of these Arctic diatoms is somewhat different from that of those on the Antarctic ice. In the Arctic they are more on the surface, while in the Antarctic they are confined more or less to a thin lamina at sea-level, above which lies the remnant of the winter snow. In fact, the diatoms of Arctic ice are altogether different species from those of Antarctic ice. And while diatoms have nothing to do with bears, it is quaint to notice that in the Arctic Regions the yellow ice patches hide the polar bear from vision; in the Antarctic regions, where the yellow diatom material is, as a rule, covered with white snow, there are no bears to benefit by being lost among yellowish patches of their own colour. Later on I will say more about bears: just now let us remember their wonderful resemblance to the yellow diatom patches on the Arctic floes.

The diatoms of the Arctic floes and pack ice are also otherwise interesting. Certain species and varieties of diatoms found on the Greenland pack, which drives southward down the east coast of Greenland, are identical to those found near Behring Strait, and this was one of the reasons that made Nansen confident that the Fram would drift across the polar basin from the Siberian Islands to the Greenland Sea.

Now all these diatoms that have been referred to are distinctly associated with sea-water ice, and according to Cleve the Arctic ones "take their origin from salt water," and not from the land. In Antarctic ice the diatoms are all marine forms: but they probably live in the sea water permeating the ice in the lamina, which occurs in the pieces of pack ice at sea-level, below the surface snow, since those floating freely in the Antarctic seas appear to be different species from those found in this lamina.

On the surface of the sea, in all parts of the world, diatoms and other algæ occur, and sometimes in such dense masses as to colour the sea. Scoresby (Arctic Regions, i, p. 176) noted that in the Greenland Sea the colour of the water was in places nearly grass-green. In the North Atlantic Ocean, in the spring of 1893, I saw bands of brilliant emerald green, like green meadows stretching for miles over the otherwise bright blue sea. And in the South Atlantic the Scotia passed through similar bands of a bright orange colour. These orange bands were fully thirty feet wide, and stretched several miles in length, and Dr. Rudmose Brown found they were composed of a gelatinous scum consisting chiefly of microscopic algæ (Trichodesmium) closely allied to diatoms. It is interesting to note that in this scum were numbers of Portuguese men-of-war, jelly-fish, swimming-bells, and crustaceans, and many other forms of animal life.

I make special mention of these remarkable occurrences because it is quite plain that all these animals were there dependent directly or indirectly on these unicellular algæ; some of the animals were feeding on the algæ themselves, others were preying on those very animals which had become luscious with the good pasture they had fed upon, and these in their turn were devoured by their larger and more rapacious brethren. Why the diatoms were there is a more puzzling question, but there must have been sufficient nitrogenous and other food material to make them thrive so well—possibly the excreta or rotting carcase of a whale!

Now in the Antarctic seas, especially during my cruise in 1892 and 1893, I have recorded in my diary day after day such entries as these: "sea dirty green"; "sea dirty brown"; "sea dirty olive-brown"; "brownish green sea"; "olive-brown sea"; "sea green"; "water olive-green colour," and so on. When the silk tow-net was put over, it was quickly filled with a gelatinous mass, which adhered persistently to the silk, and which, even after thorough washing, blocked up the fine meshes, which could not be washed clear of it. On examination I found this slimy mass to be composed of Corethron cryophyllum and other diatoms.

Like the yellow bands of algæ in the South Atlantic Ocean, the immense quantity of diatoms and other algæ floating in the polar seas doubtlessly forms the basis of the enormous abundance of animal life there, from the small copepods and euphausia to the innumerable birds, seals, and giant whales. The nature of this discoloration of Arctic waters was shown by the late Dr. Robert Brown (Transactions, Botanical Society, Edinburgh, vol. ix, 1867) to be due to the presence of enormous numbers of diatoms, among which lives a wealth of animal life, including medusoids, small crustaceans, and especially "winged" gastropods (Clio). There are such quantities of these diatoms that their siliceous skeletons, which are of a most indestructible character, form a great ring of deposit known as diatom ooze at the bottom of the deep southern ocean, all round the South Polar Regions. Deep-sea deposits will be considered in due course, but at present I wish to call attention to a remarkable fact, namely, that the distribution of the diatoms on the surface is different from their distribution on the bottom. The maximum occurrence of diatoms in the surface waters is south of 60° S., whereas the maximum occurrence of diatoms at the bottom is in about 51° and 52° S. This is doubtless due to strong undercurrents running in a northerly direction, which carry the delicate skeletons northwards as they sink downwards towards the depths. This rain of diatom ooze must form food for minute forms of animal life, which in their turn fall a prey to larger animals living in intermediate and great depths.

The diatoms of the Polar Regions, however, are not all marine forms. I have examined hundreds of land forms in the Arctic Regions, especially during my wintering in 1896 and 1897 in Franz Josef Land. Doubtless, also, there are species of diatoms that belong to Antarctic lands. "On several occasions, notably on December 18th and 20th, 1892, I saw bergs which were fringed with pale brown streaks, like a vein apparently sandwiched in their main mass," and I believe that this coloration was due to diatoms or some other forms of algæ. This observation refers to tops of bergs that were possibly 150 feet above sea-level, and which had not been overturned. The tops being inaccessible, it was impossible to get a specimen. But I have seen similar coloration on land ice in the north.

One of the most remarkable instances of coloration of ice and snow on the land is what is known as "red snow," which is due to a blood-red microscopic alga known as Sphærella nivalis. I have seen acres of ice and snow red with this alga in Prince Charles Foreland, and other parts of Spitsbergen, as well as in Novaya Zemlya and Franz Josef Land, and on one occasion we found small patches at Scotia Bay in the South Orkneys. I have not seen it on other Antarctic lands I have visited, and am not aware that other explorers, except Dr. Charcot, who saw it in Western Graham Land, and Mr. Priestly, have recorded its presence. Mr. James Murray, who accompanied Sir Ernest Shackleton, writes to me saying: "I never saw red snow, but our geologist, Priestly, saw the snow smeared with red (some 30 or 40 miles from our camp). He collected some, but abandoned his specimens while saving his life after being carried away on a floe. In a lake close by was our now familiar red rotifer, and he suspected it caused the red snow. Certainly it could do so, if the water swarming with rotifers were blown out over the snow during a gale; they would not be killed by the cold. I find that Agassiz's red snow from the Alps contained red rotifers, probably the same kind." Lagerheim also reported finding rotifers in red snow in Nicaragua. It is quite clear, however, that it does not occur so frequently in the south as it does in the north, probably mainly owing to the higher summer temperatures that occur in the north. The red snow alga is not confined to ice and snow, and I do not consider that ice and snow is its chief habitat. Mr. George Murray, late of the British Museum, told me that he had known of this alga in the cistern of a London house. If one examines the dried-up shallow ponds and pools scattered all over Arctic lands in the late summer, when their water supply fails owing to lack of melting snow, one often finds the whole bottom of such ponds covered with a dark reddish-brown scum, which dries up into a sort of skin, covering all the ground and wrapping itself round every stone. On examination this is found to be composed mainly of Sphærella nivalis. This red scum appears to thrive especially where such pools have been enriched in nitrogenous matter by water which has run down the rocks and taluses where great numbers of birds resort for nesting. It is often found that a glacier or snow-patch is coloured red when water flows over it from rocks where birds are nesting, and the well-known Scottish Arctic explorer Lamont, who has so ably depicted many an Arctic scene and incident, has ascribed the colour as being due to the droppings of the rotge, or little auk, which are, as he points out, of blood-red colour. But I have examined such patches of red snow and ice microscopically, and have found the redness due to the presence of the red snow alga. It is certain, however, that the droppings of the rotge will so enrich the water with nitrates that the red alga, which is growing plentifully, though invisibly, on the black rocks and ground, thrives exceedingly and is carried, and lives and grows on the melting surface of the snow or glacier ice. I have seen glaciers coloured green and black as well as red. The green colour is certainly due to green algæ, and the black, in certain cases, I have found to be due to fragments of desiccated lichen, fragments which do not appear to be growing on the ice but are there just as any other dust might be.

From this it will be seen that sea ice especially, and even the surface of glacier ice is swarming with life, and is by no means so sterile as it is usually thought to be. Bacteriological examination has demonstrated that the air of the Polar Regions is sterile, but under natural conditions in the Polar Regions, as in other regions, we may lay down a general law, and say—Where there is water there is life! It matters not whether this water be frozen with all the rigour of a polar winter, subjected even to over one hundred degrees of frost (F.). Melt this ice, whether fresh or salt, and life will be found. In Franz Josef Land I melted out solidly-frozen pieces of wet moss and soil, that had been subjected to a temperature of -45° F. or 77 degrees of frost, and as soon as they were melted myriads of animals and plants began "to live, and move, and have their being," after a death-like winter sleep. Many algæ and even the mosses themselves continued life where they had suddenly stopped active living with the onrush of the winter frost. They had remained dormant during several winter months, and now active life suddenly began again. Innumerable wheel animalcules (Rotifera) and water-bears (Tardigrada) once more began to move and live, and in one case a small nematode worm that had evidently been on the point of laying its eggs when overtaken by the frost months previously, began to lay them as soon as it had melted out, and continued its life as if nothing had happened during this long period of sleep. The researches of Mr. James Murray in the Antarctic Regions have since demonstrated the same phenomena, and he has further demonstrated that the Antarctic rotifers, after being frozen and melted, and then dried, can be subjected to the temperature of boiling water for a short time and yet continue to live.

The preservation of wooden crosses on old graves in Spitsbergen and other parts of the Arctic Regions as well as the remnants of wooden houses three centuries old, to say nothing of much of the driftwood which must have been left high and dry many centuries ago, is a striking piece of evidence of the sterility of the Arctic Regions from bacteria. The time will certainly come when a country like Spitsbergen and other parts of Polar Regions will be utilized as sanatoria, at least for the summer months. Concerning the bacterial sterility of the atmosphere, we have the striking facts that, under ordinary conditions, it is not possible to "catch cold" in Polar Regions, and that every germ disease is checked. A person who has a tendency to rheumatism in Britain or any similar country will not be attacked by rheumatism (unless possibly he is a very chronic rheumatic subject) in the Polar Regions, though he may be night and day in a wet camp, continually soaked. It is possible to take a pleasant short sleep, if one is sufficiently tired, on soft slushy snow on a glacier in an exposed position and to be refreshed and to suffer no ill effects whatever despite a thorough soaking; you may get chilly, but you will not "catch cold," or get pneumonia and the like. Infectious fevers are practically unknown well within the Polar Regions, unless possibly contracted in a dirty shop or a filthily-kept house, and even then it is more than likely that no fever would be contracted during the winter months. Generally speaking we may say germ diseases are unknown well within the Polar Regions. People die of old age, organic troubles, such as various forms of heart disease, and by accident; not from germ diseases. Convalescents from serious illnesses rapidly recover, and get renewed health, such as they have never enjoyed before, and wounds heal effectively and with rapidity. Payer, speaking of Dr. Börgen's terrible wounds, says: "The first operation was upon the cabin table. And here we may briefly notice the singular fact that, although he had been carried more than 100 paces with his skull almost laid bare, at a temperature of -13° F., his scalp healed so perfectly that not a single portion was missing;" and Dr. Börgen himself says, "Nor during the process of healing, which progressed favourably, did I experience the smallest pain" (The German Arctic Expedition of 1869–70, by Captain Koldeway, vol. ii, pp. 408 and 410). The darkness of winter is the chief enemy of man, as well as man himself. Provided a man lives a decently disciplined life there is no more healthy place in the world than the Polar Regions. It is the invariable experience of every well-organised polar expedition that the individuals increase in bodily health. Outside accidents, certain forms of heart disease have been about the only cause of death, and in these cases the trouble was probably present in its initial stages before the person joined the expedition, when it was difficult to detect, even by highly-skilled physicians; in such cases the patients probably could not have been saved from death even though they had never gone to the Polar Regions. It was stated, some years ago, that the death-rate of polar expeditions was less than that of the healthiest town in Britain, even including such disasters as the Franklin and Greely expeditions. Now, with better scientific organisation, the average death-rate has in all probability fallen much lower than this estimate.