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SOUTHERLY DRIFT OF ICE.
these agencies, and it is quite reasonable to suppose any other feasible cause. Passing over the discovery of 64° F. at this depth, we still have to account for the water of 42° F. flowing southwards, as evidenced by the increase of its temperature as we proceeded northwards.
It is clear that this question of temperature requires further investigation ; and it is also clear that whatever the result may be, it will materially affect all the prevailing theories respecting oceanic currents. It is not improbable that this warm water flows from the circumpolar region; and if so it would indicate a circumpolar sea.
Many facts are known which are consistent with this view. Every year the edge of the pack-ice, and the ice-fields themselves, break up and drift south, at a rate sometimes equal to thirteen miles a day, as found by Captain Parry. This does not occur when the northern ocean is wholly covered with ice, in the winter season. The drifting of the ice (as also currents) implies a sea free of ice somewhere in the north, occupying an area at least as extensive as the drift-ice. As has been seen, some of the ice is the result of more than one year's growth ; and as the ice travels southerly, say, from four to thirteen miles or more per diem, a similar area of open sea must be simultaneously forming round the pole, the ice-holes
and clear spaces in the drift-ice being quite insufficient to make up for the space left by the ice during the summer. The great abundance of animal life in the waters of the highest latitudes reached indicates that the water is not ice-cold ; and the migration of numerous species to the north of 80° shows that the means of subsistence can be obtained. There is reason to believe that whales occur far to the north of 80°; and if so, there must necessarily be sufficient open water to allow of their finding ready access to air.
In the Spitzbergen seas a blue, cloud-like appearance is well known as a sign of open water; and this has been seen on the distant north horizon even by ships which have been beset by ice in the highest latitudes. Icebergs, it is well known, waste more rapidly below the surface than in the air, causing them to topple over frequently, obviously the effect of the warm current.
The question, then, is, from whence do the warm waters come ? and how do they acquire their heat ? And this is one of the questions which a polar voyage by way of Spitzbergen would almost certainly elucidate. Another important subject of investigation would be the conditions under which the prevalent north winds of high latitudes originate. There is one argument bearing upon the temperature of the circumpolar
seas which should not be overlooked. During six months of the year the sun is above the horizon ; and although the rays may be oblique, still the waters may acquire a higher temperature than under similar conditions farther south, owing to there being little or no cooling from nocturnal radiation, and probably to the constant dryness of the air allowing the sun to strike with full power. During the winter these causes would intensify the cold.
The occurrence of warm water is by no means confined to the sea around Spitzbergen ; but, before referring to other regions, we may mention that a set of instruments for taking soundings and deep-sea temperatures was supplied this year by Mr. Smith to Captain David Grey, of the whaler Eclipse, whose father, in the year 1855, supplied the valuable information and survey of the extension of Pond's Bay, now called Eclipse Sound. His observations were made in the middle of the sea, between Greenland and Norway, and along a line running north-easterly from Iceland. They coincide with Dr. Carpenter's observations, proving the termination of the Gulf Stream. In June, 1854, Morton advanced beyond Kennedy Channel, and saw open water as far as the horizon, visible from a hill 500 feet high. The wind was from the north-west, and a rain cloud was seen in the distance above the open sea. The water was setting in a strong current south, and the ice along the shores was in a rapid state of dissolution. The water was found in the several places tried to be well-above the freezing-point; and in one place, some distance from the ice-foot, and at a depth of 5 feet, the temperature was 40° F. There was a strong tide from the north. Kane's vessel wintered in Renselaer Harbour ; the strait was bridged across by ice, with a current running south flowing beneath it. Although the open waters above alluded to may not be direct evidence of a comparatively mild circumpolar region, yet the stream of warm water coming from the north seems to indicate it.
Where can this water acquire its warmth ? Sir John Richardson suggests that it is derived from the warm area near Spitzbergen ; but this is not supported by evidence, which indicates that in both areas the water comes from the north. It has been suggested that it is a continuation of the Gulf Stream, apparently because it is supposed to supply all the warm water in the Arctic seas; but if there is no reason for believing that the warm sea around Spitzbergen derives its heat from this source, it is still less credible in the case of the KennedyStrait water. It has been suggested that the source of warmth is the northward flow of the general mass of the North Atlantic. If this did account for the warmth of the Spitzbergen area, although this view would be with difficulty reconciled with a southward