173; National Antarctic Exp., Nat.
Tasman sailed from Batavia in 1642, and on the 24th of November sighted high land in 42° 30' S., which was named van Diemen's Land, and after landing there proceeded to the discovery of the western coast of New Zealand; at first called Staten Land, and supposed to be connected with the Antarctic continent from which this voyage proved New Holland to be separated.
(1893); Hedley, " Surviving Refugees in Austral Lands of Ancient Antarctic Life," Royal Society N.
For purposes of measurement the polar boundaries are taken to be the Arctic and Antarctic circles, although in discussing the configuration and circulation it is impossible to adhere strictly to these limits.
The chief element of uncertainty as to the largest features of the relief of the earth's crust is due to the unexplored area in the Arctic region and the larger regions of the Antarctic, of which Crustal we know nothing.
The most important were: the Australian Antarctic expedition of 1911-4 under Sir Douglas Mawson; the Danish Oceanographical expeditions in the Mediterranean and adjacent seas of 1908-10; a short cruise made by Sir John Murray and Dr. Johan Hjort in the Norwegian Fishery exploring vessel " Michael Sars " in 1910, the general results of which were published as The Depths of the Ocean (1912) by the leaders of the expedition; and a short special cruise made by the " Scotia " in 1913 (after the loss of the " Titanic ") under the leadership of Dr. Matthews, which made observations upon the distribution of ice in the North Atlantic.
Leaving Hampton Roads on the 18th of August 1838, it Mopped at Madeira and Rio de Janeiro; visited Tierra del Fuego, Chile, Peru, the Paumotu group of the Low Archipelago, the Samoan islands and New South Wales; from Sydney sailed into the Antarctic Ocean in December 1839 and reported the discovery of an Antarctic continent west of the Balleny islands; visited the Fiji and the Hawaiian islands in 1840, explored the west coast of the United States, including the Columbia river, San Francisco Bay and the Sacramento river, in 1841, and returned by way of the Philippine islands, the Sulu archipelago, Borneo, Singapore, Polynesia and the Cape of Good Hope, reaching New York on the 10th of June 1842.
Modern naturalists consider that many of the problems of Australia's remarkable fauna and flora can be best explained by the following hypothesis: - The region now covered by the antarctic ice-cap was in early Tertiary times favoured by a mild climate; here lay an antarctic continent or archipelago.
As a step towards such hypothesis it has been noted that the Antarctic, the South African, and the Australian floras have many types in common.
Before the Antarctic expeditions of 1903-1904 our knowledge of the form of the sea bottom south of 40° S.
Long., in which he recorded a depth exceeding 4000 fathoms. The Scottish Antarctic expedition has shown this sounding to be erroneous; the " Scotia " obtained samples of bottom, in almost the same spot, from a depth of 2660 fathoms. Combining the results of recent soundings, Dr W.
The prince of Monaco, the German " Valdivia " expedition under Professor Chun (1898), and the combined Antarctic expeditions (1903-1904).
The North Atlantic being altogether cut off from the Arctic regions, and the vertical circulation being active, this movement is here practically non-existent; but in the South Atlantic, where communication with the Southern Ocean is perfectly open, Antarctic water can be traced to the equator and even beyond.
In 1642 the governor and council of Batavia fitted out two ships to prosecute the discovery of the south land, then believed to be part of a vast Antarctic continent, and entrusted the command to Captain Abel Jansen Tasman.
The belief in a vast Antarctic continent stretching far into the temperate zone had never been abandoned, and was vehemently asserted by Charles Dalrymple, a disappointed candidate nominated by the Royal Society for the command of the Transit expedition of 1769.
Cook's second voyage was mainly intended to settle the question of the existence of such a continent once for all, and to define the limits of any land that might exist in navigable seas towards the Antarctic circle.
On a second cruise from the Society Islands, in 1773, he, first of all men, crossed the Antarctic circle, and was stopped by ice in 71° 10' S.
To these might be added the antarctic, which is still very imperfectly known.
In this way, for example, it has been suggested that a land, " Lemuria," once connected Madagascar with the Malay Archipelago, and that a northern extension of the antarctic land once united the three southern continents.
Antarctic and southern temperate coasts.
The distribution is very interesting and it has been shown that the water of the Antarctic Ocean contains about 0 .
This is really the case, for all observations show that the Antarctic and Arctic ice-bound seas are enormously rich in diatom life when compared with temperate and tropical regions: the great Antarctic zone of sea-bottom deposit, in which the skeletons of diatoms predominate, covers some ten millions of square miles.
It must be remembered that the Arabs, who inhabit an extremely hot country, are very fully clothed, while the Fuegians at the extremity, of Cape Horn, exposed to all the rigours of an antarctic climate, have, as sole protection, a skin attached to the body by cords, so that it can be shifted to either side according to the direction of the wind.
That Wilkes discovered an Antarctic continent was long doubted, and one of the charges against him when he was court-martialled was that he had fabricated this discovery, but the expedition of Sir Ernest Shackleton in 1908-1909 corroborated Wilkes.
That part of the Antarctic continent known as Wilkes Land was named in his honour.
A simple, practical boundary between the three oceans can be obtained by prolonging the meridian of the southern extremity of each of the three southern continents to the Antarctic circle.
A committee of the Royal Geographical Society - the deliberations of which were interrupted by the departure on his last voyage of Sir John Franklin, one of the members - suggested these meridians as boundaries; the north and south boundaries of the Atlantic and Pacific Oceans being the polar circles, leaving an Arctic and an Antarctic Ocean to complete the hydrosphere.
We now know, however, that the Antarctic circle runs so close to the coast of Antarctica that the Antarctic Ocean may be left out of account.
As limits; but in none of these schemes has the coast of Antarctica been adequately considered, and they have all been too much influenced by the Mercator map. Each of the three oceans, Atlantic, Indian and Pacific, possesses an Antarctic facies in the southern part and a tropical facies between the tropics, and the Atlantic and Pacific an Arctic facies in their northern parts.
The North African Basin has several deeps with more than 3300 fathoms to the northwest and the south-west of the Cape Verde Islands, but the South African Basin is less deep. In the South Atlantic there is no connexion between the Central Rise and the Antarctic Shelf, for the Indo-Atlantic Antarctic Basin stretches from near the South Sandwich Islands towards Kerguelen with depths exceeding 2500 fathoms and reaching in places 3100.
In the Indian Ocean the Kerguelen Rise stretches broadly southward, east of the island which gives it a name, to the Antarctic Shelf with the greatest depths upon it usually less than 2000 fathoms, and it stretches northward beyond New Amsterdam to 30° S.
This rise is separated from the Crozet Rise by a depression extending to 2675 fathoms, through which the Kerguelen Trough (which lies north of Kerguelen) is brought into free communication with the Indo-Atlantic Antarctic Basin.
The Pacific Ocean consists mainly of one enormous basin bounded on the west by New Zealand and the Tonga, Marshall aid Marianne ridges, on the north by the festoons of islands marking off the North Pacific fringing seas, on the east by the coast of North America and the great Easter Island Rise and on the south by the Antarctic Shelf.
The Pacific Antarctic Basin occupies the vast region south of 50° S.
It is particularly in evidence round the whole of the Antarctic Shelf, where it occurs down to depths of 2500 fathoms. It is the chief deposit, according to Nansen, of the North Polar Basin and, according to Schmelck and Bdggild, of the Norwegian Sea also, where it is largely mixed with the shells of the bottom-living foraminifer Biloculina.
For the open ocean the only quite trustworthy results are those obtained by the prince of Monaco in the North Atlantic, and by the recent Antarctic expeditions in the South Atlantic and South Indian Oceans.
As the Arctic Basin is shut off from the North Atlantic by ridges rising to within 300 fathoms of the surface and from the Pacific by the shallow shelf of the Bering Sea, and as the ice-laden East Greenland and Labrador currents consist of fresh surface water which cannot appreciably influence the underlying mass, the Arctic region has no practical effect upon the bottom temperature of the three great oceans, which is entirely dominated by the influence of the Antarctic. The existence of deep-lying and extensive rises or ridges in high southern latitudes has been indicated by the deep-sea temperature observations of Antarctic expeditions.
Prevail right northwards across the equator into the Bay of Biscay, showing a steady rise of bottom temperature as successive submarine elevations restrict communication with 'the Antarctic. On the other hand, in the more open Argentine Basin, which carries deep water far to the south, the bottom temperature in 40° S.
In similar depths in the Pacific south of the equator temperatures of 33.8° to 34.5° are found, and north of the equator bottom temperatures at the same depth increase to 35.1° in the neighbourhood of the Aleutian Islands, again completely justifying the conclusion as to the Antarctic control of deep water temperature throughout the ocean.
In the course of a year, while in the Antarctic regions the season's growth is only half as great; in the latter also the accumulated snow is an important factor in the thickness of the ice, and snow is an even worse conductor of heat.
In the southernhemisphere the icepack forms a nearly continuous fence around the Antarctic continent.
In the north, icebergs break off, as a rule, from the ends of the great glaciers of Greenland, and in the far south from the edge of the great Antarctic ice-barrier.
Strongly marked differences in density are produced by the melting of sea-ice, and this is of particular importance in the case of the great ice barrier round the Antarctic continent.
The existence of a layer of water of low salinity at a depth of 500 fathoms in the tropical oceans of the southern hemisphere is to be referred to this action of the melting ice of the Antarctic regions.
It appears to be common in the neighbourhood of Cape Town, while the recent Antarctic expeditions have shown that it occurs in various localities from the Falkland Islands to the Antarctic circle.
In the extreme south, where an Arctic vegetation is found, the pastures are rich, and the forests, largely of the Antarctic beech (Fagus antarctica), are vigorous wherever the rainfall is heavy.
The Antarctic beech and Winter's bark (Drimys Winteri) are found at intervals along the Andes to the northern limits of this zone.
In reality, however, it experiences fewer climatic variations than the other great continents, owing to its distance (28°) from the Antarctic circle and (11°) from the equator.
It is not to be supposed that this antarctic element, to which Professor Tate has applied the name Euronotian, entered a desert barren of all life.
The voyage of Drake across the Pacific was preceded by that of Alvaro de Mendana, who was despatched from Peru in 1567 to discover the great Antarctic continent which was believed to extend far northward into the South sea, the search In Pacific. for which now became one of the leading motives of Pacific. exploration.
And their flora is much the same as that of Antarctic South America.
They are essentially coast-fishes, inhabiting nearly all seas, but disappearing towards the Arctic and Antarctic Oceans.
South of the magnetic equator the south end of the needle is always inclined downwards, and there is a spot within the Antarctic Circle (148° E.
Others, like Malte Brun (1803) and Supan (1903), take the loxodromes between the three capes and call the ocean to the south the Antarctic Ocean.
The rise resumes a southerly direction and from Ascension to Tristan d'Acunha, the depth is in many places less than r50o fathoms. The soundings of Bruce's Antarctic expedition in the " Scotia " showed that the rise cannot be traced beyond 55° S.
Right up to the Antarctic Shelf, with depths ranging down to 2500-3000 fathoms, and communicating with the main Pacific Basin to the east of New Zealand.
The Antarctic icebergs are of tabular form and much larger than those of Greenland, but in either case an iceberg rising to 200 ft.
Though the islands are under the equator, the climate is not intensely hot...