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and Tromsö was reached on October 4. In September, 1871, Captain Carlsen revisited Barent's House in Ice Haven, followed the east coast of Nova Zembla, and by passing through the Vaigatz Strait he circumnavigated that island. In 1871 Captain Mack sailed from Tromsö as far as 82° 30' E. Captain Johannesen sailed about the Sea of Kara as late as October without seeing ice. Several other captains made voyages in the seas near Spitzbergen and Nova Zembla, during which they met with little or no ice from early in June to late in October. In 1872 another Swedish expedition was sent to Spitzbergen. According to the programme, it is proposed to explore the eastern Spitzbergen Sea, and to map the whole of the eastern lands; to make a continuous series of meteorological and magnetical observations; and to carry out researches on the pendulum, as also in botany, geology, zoology, and other natural sciences. It is also intended to make another attempt to reach the Pole by means of reindeer and sledges. In the summer of 1872 Captain Altmann found the sea east of Spitzbergen free from ice, and saw eight islands occupying the position assigned by Petermann to King Charles's Land. The south end of the westernmost island is in 78° 43' N. and 28° 5' E., and the most easterly is in 79° 3' N. and 32° 17' E. He sailed between the

INTRODUCTORY CHAPTER.

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islands until he reached the ice-fields to the east of the easternmost island; and, although the weather was clear, he could see no land to the north. This is not the Gillis Land of old geographers, which is probably identical with another group of islands about sixty miles farther north. In the summer of 1872, Captain Johnsen also cruised in this region. He sighted land in 78° 18' 46" N. and 30° E., which he reports as belonging to a large island forty-four miles long, the shore of which is covered with drift-wood. He sailed along the east and south shores of this land, which were free from ice; there was ice at the north end. In this year also the second cruise of the Sampson schooner yacht took place to the Spitzbergen Seas, of which an account is given in the present volume. Although it was an unusually close season, she reached 80° 30' N., 12° E.; her further. advance being checked by a leak caused by ice nips. She sailed from the Shetlands, May 29 ; left Widde Bay on her return, August 17, and reached Hull, September 26. In 1871 she reached 81° 15' N.

The above sketch shows that except at a few points we know very little respecting the seas and lands situated to the north of about 75°. The degree of flattening in the polar region, and hence the true form of the earth can only be ascertained by the measurement of arcs in all latitudes, or by numerous pendulum observations. This is a point, the settlement of which is of considerable importance in physical science. Very little is known respecting the meteorology of the polar region. This science is in its infancy, and yet it is abundantly manifest that the various phenomena of climate are regulated by definite laws, of which only glimpses are as yet perceptible, and that a knowledge of the circumpolar climate would be an essential aid to the meteorologists of more temperate climates towards ascertaining what those laws are. The peculiar condition of these regions with respect to solar heat and light opens up a field of investigation which has as yet scarcely been touched. Within the Arctic Circle, the longest day or period of constant light and heat varies from twenty-four hours at 66° 30' N. to six months at the Pole. At the Pole the sun would be first seen above the horizon at the spring equinox, and would not again sink below it till the autumnal equinox. Early in the season its altitude would be very low, but as time went on its height would steadily increase until June 21, when the sun's declination would be 23° 28'. After this it would gradually sink. At a certain distance south of the North Pole the period of constant daylight would be five months, but the sun would attain a greater

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maximum height in the sky. During the midsummer months the sun would acquire considerable heating power, and this power would be so constant, and free from diminution by nocturnal cooling, that the land and waters would become warmed, and would absorb heat. This heat would be gradually liberated later in the year. The local distribution of heat would be modified by the nature of the ground, the height of land, and the distribution of sea and land ; but it is theoretically probable that at the Pole the mean temperature of the air in July and August is much higher than it is generally thought to be. During the winter the continuousness of the night would equally favour a very low temperature, so that probably the range of temperature in the circumpolar area is greater than in any other part of the globe. Evidences of high summer temperature are not entirely wanting. Many of the most northern coasts reached are strewed with drift-wood, and even trunks of trees, which in many cases appear to have come from the north. A list of the species thus occurring would throw light upon the probable localities where they grew. Again, streams or outflows of warm water from the Pole have been observed in many localities. · These, wherever met with, are commonly assigned to the Gulf Stream ; but as will be noted in a subsc

quent chapter, the warm water originates at the Pole. This is a question which requires investigation. There are many other questions connected withi Polar temperature of a very complicated and involved character, which cannot be fully entered into here. One or two may be alluded to. It is known that the mean temperature of the Southern hemisphere is lower than that of the North ; and it is a matter of observation that the Antarctic Pole is more extensively ice-clad than the Arctic. This may be in part conjecturally explained by the greater extent of land at the South than at the North Pole. It is also known that the earth revolves round the sun in an elliptic orbit, so that it is at one time nearer the sun than at another. At the present time the Poles are farther from the sun in summer and winter than in spring and autumn. It has already been indicated that the North Pole is warmed up during the summer; and as the warming of the South Pole occurs under similar conditions as regards heat, &c., the South Pole should have a similar temperature whereas it is the coldest. This is probably indicative of the North Pole being for the most part surrounded by water. During the spring the heat is being gradually increased by the gradually increasing height of the sun, which increase is in part counterbalanced by the

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