South! The Story of Shackleton's Last Expedition, 1914-1917 Part 24

The work undertaken and accomplished by each member was as wide as possible; but it was only in keeping with the spirit of the times that more attention should be paid to work from which practical and economic results were likely to accrue. The meteorologist had always in view the effect of Antarctic climate on the other southern continents, the geologist looked on ice from a seaman's point of view, and the biologist not unwillingly put whales in the forefront of his programme.

The accounts which follow on these very practical points show how closely scientific work in the Antarctica is in touch with, and helps on the economic development of, the inhabited lands to the north.

SEA-ICE NOMENCLATURE By J. M. WORDIE, M.A. (Cantab.), Lieut. R.F.A.

During the voyage of the 'Endurance' it was soon noticed that the terms being used to describe different forms of ice were not always in agreement with those given in Markham's and Mill's glossary in "The Antarctic Manual," 1901. It was the custom, of course, to follow implicitly the terminology used by those of the party whose experience of ice dated back to Captain Scott's first voyage, so that the terms used may be said to be common to all Antarctic voyages of the present century. The princ.i.p.al changes, therefore, in nomenclature must date from the last quarter of the nineteenth century, when there was no one to pa.s.s on the traditional usage from the last naval Arctic Expedition in 1875 to the Discovery Expedition of 1901. On the latter ship Markham's and Mill's glossary was, of course, used, but apparently not slavishly; founded, as far as sea-ice went, on Scoresby's, made in 1820, it might well have been adopted in its entirety, for no writer could have carried more weight than Scoresby the younger, combining as he did more than ten years' whaling experience with high scientific attainments. Above all others he could be accepted both by practical seamen and also by students of ice forms.

That the old terms of Scoresby did not all survive the period of indifference to Polar work, in spite of Markham and Mill, is an indication either that their usefulness has ceased or that the original usage has changed once and for all. A restatement of terms is therefore now necessary. Where possible the actual phrases of Scoresby and of his successors, Markham and Mill, are still used. The principle adopted, however, is to give preference to the words actually used by the Polar seamen themselves.

The following authorities have been followed as closely as possible:

W. Scoresby, Jun., "An Account of the Arctic Regions," 1820, vol. i, pp. 225-233, 238-241.

C. R. Markham and H. R. Mill in "The Antarctic Manual," 1901, pp. xiv-xvi.

J. Payer, "New Lands within the Arctic Circle," 1876, vol. i, pp. 3-14.

W. S. Bruce, "Polar Exploration" in Home University Library, c. 1911, pp. 54-71.

Reference should also be made to the annual publication of the Danish Meteorological Inst.i.tute showing the Arctic ice conditions of the previous summer. This is published in both Danish and English, so that the terms used there are bound to have a very wide acceptance; it is hoped, therefore, that they may be the means of preventing the Antarctic terminology following a different line of evolution; for but seldom is a seaman found nowadays who knows both Polar regions. On the Danish charts six different kinds of sea-ice are marked--namely, unbroken polar ice; land-floe; great ice-fields; tight pack-ice; open ice; bay-ice and brash. With the exception of bay-ice, which is more generally known as young ice, all these terms pa.s.s current in the Antarctic.

"Slush" or "Sludge". The initial stages in the freezing of sea-water, when its consistency becomes gluey or soupy. The term is also used (but not commonly) for brash-ice still further broken down.

"Pancake-ice". Small circular floes with raised rims; due to the break- up in a gently ruffled sea of the newly formed ice into pieces which strike against each other, and so form turned-up edges.

"Young Ice". Applied to all unhummocked ice up to about a foot in thickness. Owing to the fibrous or platy structure, the floes crack easily, and where the ice is not over thick a ship under steam cuts a pa.s.sage without much difficulty. Young ice may originate from the coalescence of "pancakes," where the water is slightly ruffled or else be a sheet of "black ice," covered maybe with "ice-flowers," formed by the freezing of a smooth sheet of sea-water.

In the Arctic it has been the custom to call this form of ice "bay- ice"; in the Antarctic, however, the latter term is wrongly used for land-floes (fast-ice, etc.), and has been so misapplied consistently for fifteen years. The term bay-ice should possibly, therefore, be dropped altogether, especially since, even in the Arctic, its meaning is not altogether a rigid one, as it may denote firstly the gluey "slush," which forms when sea-water freezes, and secondly the firm level sheet ultimately produced.

"Land floes". Heavy but not necessarily hummocked ice, with generally a deep snow covering, which has remained held up in the position of growth by the enclosing nature of some feature of the coast, or by grounded bergs throughout the summer season when most of the ice breaks out. Its thickness is, therefore, above the average. Has been called at various times "fast-ice," "coast-ice," "land-ice," "bay-ice" by Shackleton and David and the Charcot Expedition; and possibly what Drygalski calls "Schelfeis" is not very different.

"Floe". An area of ice, level or hummocked, whose limits are within sight. Includes all sizes between brash on the one hand and fields on the other. "Light-floes" are between one and two feet in thickness (anything thinner being "young-ice"). Those exceeding two feet in thickness are termed "heavy floes," being generally hummocked, and in the Antarctic, at any rate, covered by fairly deep snow.

"Field". A sheet of ice of such extent that its limits cannot be seen from the masthead.

"Hummocking". Includes all the processes of pressure formation whereby level young ice becomes broken up and built up into

"Hummocky Floes". The most suitable term for what has also been called "old pack" and "screwed pack" by David and "Scholleneis" by German writers. In contrast to young ice, the structure is no longer fibrous, but becomes spotted or bubbly, a certain percentage of salt drains away, and the ice becomes almost translucent.

The Pack is a term very often used in a wide sense to include any area of sea-ice, no matter what form it takes or how disposed. The French term is "banquise de derive".

"Pack-ice". A more restricted use than the above, to include hummocky floes or close areas of young ice and light floes. Pack-ice is "close"

or "tight" if the floes const.i.tuting it are in contact; "open" if, for the most part, they do not touch. In both cases it hinders, but does not necessarily check, navigation; the contrary holds for

"Drift-ice". Loose open ice, where the area of water exceeds that of ice. Generally drift-ice is within reach of the swell, and is a stage in the breaking down of pack-ice, the size of the floes being much smaller than in the latter. (Scoresby's use of the term drift-ice for pieces of ice intermediate in size between floes and brash has, however, quite died out). The Antarctic or Arctic pack usually has a girdle or fringe of drift-ice.

"Brash". Small fragments and roundish nodules; the wreck of other kinds of ice.

"Bergy Bits". Pieces, about the size of a cottage, of glacier-ice or of hummocky pack washed clear of snow.

"Growlers". Still smaller pieces of sea-ice than the above, greenish in colour, and barely showing above water-level.

"Crack". Any sort of fracture or rift in the sea-ice covering.

"Lead" or "Lane". Where a crack opens out to such a width as to be navigable. In the Antarctic it is customary to speak of these as leads, even when frozen over to const.i.tute areas of young ice.

"Pools". Any enclosed water areas in the pack, where length and breadth are about equal.

METEOROLOGY By L. D. A. HUSSEY, B.Sc., (Lond.), Capt. R.G.A.

The meteorological results of the Expedition, when properly worked out and correlated with those from other stations in the southern hemisphere, will be extremely valuable, both for their bearing on the science of meteorology in general, and for their practical and economic applications.

South America is, perhaps, more intimately concerned than any other country, but Australia, New Zealand, and South Africa are all affected by the weather conditions of the Antarctic. Researches are now being carried on which tend to show that the meteorology of the two hemispheres is more interdependent than was. .h.i.therto believed, so that a meteorological disturbance in one part of the world makes its presence felt, more or less remotely perhaps, all over the world.

It is evident, therefore, that a complete knowledge of the weather conditions in any part of the world, which it is understood carries with it the ability to make correct forecasts, can never be obtained unless the weather conditions in every other part are known. This makes the need for purely scientific Polar Expeditions so imperative, since our present knowledge of Arctic and Antarctic meteorology is very meagre, and to a certain extent unsystematic. What is wanted is a chain of observing stations well equipped with instruments and trained observers stretching across the Antarctic Continent. A series of exploring ships could supplement these observations with others made by them while cruising in the Antarctic Seas. It would pay to do this, even for the benefit accruing to farmers, sailors, and others who are so dependent on the weather.

As an instance of the value of a knowledge of Antarctic weather conditions, it may be mentioned that, as the result of observations and researches carried out at the South Orkneys--a group of sub-Antarctic islands at the entrance to the Weddell Sea--it has been found that a cold winter in that sea is a sure precursor of a drought over the maize and cereal bearing area of Argentina three and a half years later. To the farmers, the value of this knowledge so far in advance is enormous, and since England has some three hundred million pounds sterling invested in Argentine interests, Antarctic Expeditions have proved, and will prove, their worth even from a purely commercial point of view.

I have given just this one instance to satisfy those who question the utility of Polar Expeditions, but many more could be cited.

As soon as it was apparent that no landing could be made, and that we should have to spend a winter in the ship drifting round with the pack, instruments were set up and observations taken just as if we had been ash.o.r.e.

A meteorological screen or box was erected on a platform over the stern, right away from the living quarters, and in it were placed the maximum and minimum thermometers, the recording barograph, and thermograph--an instrument which writes every variation of the temperature and pressure on a sheet of paper on a revolving drum--and the standard thermometer, a very carefully manufactured thermometer, with all its errors determined and tabulated. The other thermometers were all checked from this one. On top of the screen a Robinson's anemometer was screwed. This consisted of an upright rod, to the top of which were pivoted four arms free to revolve in a plane at right angles to it. At the end of these arms hemispherical cups were screwed. These were caught by the wind and the arms revolved at a speed varying with the force of the wind. The speed of the wind could be read off on a dial below the arms.

In addition there was an instrument called a Dines anemometer which supplied interesting tracings of the force, duration, and direction of the wind. There was an added advantage in the fact that the drum on which these results were recorded was comfortably housed down below, so that one could sit in a comparatively warm room and follow all the varying phases of the blizzard which was raging without. The barometer used was of the Kew Standard pattern. When the ship was crushed, all the monthly records were saved, but the detailed tracings, which had been packed up in the hold, were lost. Though interesting they were not really essential. Continuous observations were made during the long drift on the floe and while on Elephant Island the temperature was taken at midday each day as long as the thermometers lasted. The mortality amongst these instruments, especially those which were tied to string and swung round, was very high.

A few extracts from the observations taken during 1915--the series for that year being practically complete--may be of interest. January was dull and overcast, only 7 per cent. of the observations recording a clear blue sky, 71 per cent. being completely overcast.

The percentage of clear sky increased steadily up till June and July, these months showing respectively 42 per cent. and 45.7 per cent. In August 40 per cent. of the observations were clear sky, while September showed a sudden drop to 27 per cent. October weather was much the same, and November was practically overcast the whole time, clear sky showing at only 8 per cent. of the observations. In December the sky was completely overcast for nearly 90 per cent. of the time.

Temperatures on the whole were fairly high, though a sudden unexpected drop in February, after a series of heavy north-easterly gales, caused the ship to be frozen in, and effectually put an end to any hopes of landing that year. The lowest temperature experienced was in July, when -35 Fahr., i.e. 67 below freezing, was reached. Fortunately, as the sea was one ma.s.s of consolidated pack, the air was dry, and many days of fine bright sunshine occurred. Later on, as the pack drifted northwards and broke up, wide lanes of water were formed, causing fogs and mist and dull overcast weather generally. In short, it may be said that in the Weddell Sea the best weather comes in winter. Unfortunately during that season the sun also disappears, so that one cannot enjoy it as much as one would like.

As a rule, too, southerly winds brought fine clear weather, with marked fall in the temperature, and those from the north were accompanied by mist, fog, and overcast skies, with comparatively high temperatures. In the Antarctic a temperature of 30, i.e. 2 below freezing, is considered unbearably hot.

The greatest difficulty that was experienced was due to the acc.u.mulation of rime on the instruments. In low temperatures everything became covered with ice-crystals, deposited from the air, which eventually grew into huge blocks. Sometimes these blocks became dislodged and fell, making it dangerous to walk along the decks. The rime collected on the thermometers, the gla.s.s bowl of the sunshine recorder, and the bearings of the anemometer, necessitating the frequent use of a brush to remove it, and sometimes effectively preventing the instruments from recording at all.

One of our worst blizzards occurred on August 1, 1915, which was, for the ship, the beginning of the end. It lasted for four days, with cloudy and overcast weather for the three following days, and from that time onwards we enjoyed very little sun.

The weather that we experienced on Elephant Island can only be described as appalling. Situated as we were at the mouth of a gully, down which a huge glacier was slowly moving, with the open sea in front and to the left, and towering, snow-covered mountains on our right, the air was hardly ever free from snowdrift, and the winds increased to terrific violence through being forced over the glacier and through the narrow gully. Huge blocks of ice were hurled about like pebbles, and cases of clothing and cooking utensils were whisked out of our hands and carried away to sea. For the first fortnight after our landing there, the gale blew, at times, at over one hundred miles an hour.

Fortunately it never again quite reached that intensity, but on several occasions violent squalls made us very fearful for the safety of our hut. The island was almost continuously covered with a pall of fog and snow, clear weather obtaining occasionally when pack-ice surrounded us.

Fortunately a series of south-westerly gales had blown all the ice away to the north-east two days before the rescue ship arrived, leaving a comparatively clear sea for her to approach the island.

Being one solitary moving station in the vast expanse of the Weddell Sea, with no knowledge of what was happening anywhere around us, forecasting was very difficult and at times impossible.