The difference of temperature between the north-western shores of Europe and the north-eastern shores of America seems to be owing to two main causes—the GulfStreaso, and the drifting of the ice-maases from the chores of Siberia. The Unit-Stream Is a great warm current many miles in width, which flows in a north-eastern direction from the Out( of Mexico across the Atlantic, and passing by the British Islands and along the coast of Norway, penetrates the Polar Sea as far as the northern shores of Spitsbergen and Nova Zembla. Hero in the spring it meets the powerful current caused by the breaking-up of the ice in the gnat rivers of Siberia. As this vast body of water and broken is advances towards the shores of Nova Zembla and Spitzbergen the Gulf-Stream opposes its farther progress south and gives it a direction westward, so that it pease. by East Greenland and Iceland, and reaches the shores of America and Newfoundland, where the masses of floating ice (sometimes miles in length and of great thickness) descend in the spring as low as 40' N. lat. On the coast of Norway, on the contrary, as far as 71' N. lat., not a piece of drift-ice is aver seen.
The countries which surround the north pole generally afford an abundant supply of animal food, consisting of the walrus, the polar bear, the moose-deer, the reindeer, the wolf, the polar hare, and the seal. The number of aquatic' birds is very large, and various kinds of Bah ire in great abundance.
We now proceed to give a sketch of the discoveries which have been made in the Antarctic Seas.
The southern hemisphere, as is now well known, contains a much less proportion of land to sea than the northern hemisphere. But it was formerly supposed that the remote and then unknown parts of the southern hemisphere were occupied by an extensive continent, which surrounded the Antarctio Pole, and extended to a great distance from it. This imaginary continent, called Terra Australis Incognita, makes a conspicuous figure on all maps which are more than a century old. Little could be adduced in support of the supposed existence of this continent except some imaginary law of equipoise. In the middle of the last century however it was determined to solve the problem of the existence of this Terra Australia, and Cook undertook his second voyage (1772-1775) for the purpose. He found large masses of floating ice, and only in three places succeeded in penetrating beyond the Antarctic Polar Circle. In one place he attained 71° 10' S. lat., but he was generally unable to go much farther south than 60° S. lat. This was the case between 90° and 150° E. long., within which limits the most extensive and continuous line of coast has been since discovered. This line of coast however lies between 4° and 5° south of Cook's track. As Cook had found no laud south of 60°, the Terra Australis disappeared from our maps, though he him self thought that there must be land in the vicinity of the pole, being convinced that ice can only be formed in the neighbourhood of land.
Thus the matter rested up to 1819, when the South Shetland Islands were seen by William Smith, on a voyage from Monte Video to Valparaiso. In 1821 Powell discovered Trinity Land south of the
South Shetlands; and the South Orkneys, between 60° 30' and 61° S. lat., 44° 30' and 46° 30' W. long. Palmer, an American, discovered coast-line west of Trinity Land, which is called Palmer's Land ; and the Russian navigator, Bellingshausen, discovered Alexander's Land, south-west of Palmer's Land. In 1823 Weddell tried to find land east of the meridian of the South Shetland Islands. He did not find land, but he succeeded in advancing as far as 74' 15' S. lat., where he found a sea clear of ice. In 1831 and 1832 Biseoe sailed round the icy masses which inclose the south pole, and added to former dia. coveries Enderby's Land and Graham's Land. The first lies at a great distance from the countries south of the Shetland Islands, between 49° and 51° E long. ; but Graham's Land is between Alex ander's Land and Palmer's Land. Thus a nearly continuous coast line has been discovered south and west of the South Shetland Islands, extending from 36' to 70° W. long., and comprehending from east to west Trinity Land, Palmer's Land, Graham's Land, and Alexander's Land. In 1337 the French government sent some vessels to these parts, under the command of Dumont D'Urville, who explored the coast which Powell named Trinity Land, and changed its name to that of Louis Philippe's Land. In the following year Balleny directed his course to those parts of the ocean which are south of New Zealand and Australia, and discovered some islands in 66° 44' S. lat., 163° 11' E. long., which he called Balleny Islands. He also discovered a projecting coast-line near 116° E. long., which was called Sabrina Land. But the largest tract of sea-coast was discovered in 1840. In 1839 the Frenoh government and that of the United States of North America sent out expeditions for the purpose of making discoveries in the Antarctic) Seaa. The French expedition consisted of two vessels, under the command of Dnmont D'Urville, and the American of four vessels, commanded by Charles Wilkes. Both directed their course to the seas which the year before had been visited by Balleny. Wilkes found a coast-line in 154' 27' E. long., and in continuing his course westward for four weeks, he had either always a coast in sight, or unequivocal indications of land being at no great distance. He advanced as far 11.1 97' 30' R long., so that, including Sabrina Land, he discovered a coast-line extending over near 50 degrees of longitude. Dumont D'Urville reached the same coast in 140° 41' E. long., and pursued his course westward to 130° E. long. He called it Ad4lie Land. It is remarkable that the coast of this Antarctic Continent, if the appellation may be adopted, lies near the Antarctic) Circle, either to the south or to the north of it, and this is also the case with Enderby's Land and Graham's Land, both of which are traversed by that line. Only the tract of coast south of the South Shetland Islands extends farther north, and approaches to 63° S. lat.