صور الصفحة
PDF
النشر الإلكتروني
[ocr errors][ocr errors][ocr errors][graphic]
[merged small][ocr errors][merged small]

Land, embarking a party, but made no discoveries of importance beyond more detailed studies of ice formation and shore lines. The equipment of the expedition was meagre, and its resources inadequate for work of the first importance.

The attainment of the South Pole by Amundsen and Scott within thirty days of each other, and within three years of the discover}' of the North Pole by Admiral Peary, marks the first q uarter of the twentieth century as the most memorable in Polar exploration. See Antarctic Ocean.

Consult Antarctic Manual, with Bibliography (ed. by Murray, 1901); Borchgrevink's First on the Antarctic Continent (1901); Bernacchi's To the South Polar Regions (1901); Lecointe's Au Pays des Afanchots (Belgica Expedition, 1904); Resullats duVoyage de la S. ¥. Belgica (30 vols., in course of publication); Die Deutsche SiidpolarExpedition (1903); Nordenskjold and Anderson's Antarctica (1905); Mill's Siege of the South Pole (1905); Armitage's Two Years in the Antarctic (19O5); Scott's Voyage of the Discovery (1906); Official Reports by the French Ministry of Public Instruction of Charcot's Francois (1904-5) and Pourquois Pas (1908-10) Expeditions; The Heart of the Antarctic, by Sir E. H. Shackleton and others (1909); 'Captain Scott's Story' (London Weekly Times. April 5 and 12, 1912).

Antarctic Ocean. This great water division of the globe is in many respects the antithesis of the Arctic Ocean. The Antarctic consists of a central mass of land, covered with a thick and presumably unbroken ice cap. To this vast accumulation of ice are due the huge table-topped icebergs projecting 150 to 200 feet above the surface of the sea, and descending 1,200 to 1,500 feet below it. As the edge of the great ice barrier is approached, the ocean in many parts very perceptibly decreases in depth. For instance, east of Victoria Land, and off the adjacent Adelie Land, the depth ranges from 100 to 80O fathoms; east of the South Shetland Island, it is 100 to 500 fathoms deep; and west of Graham Land there is a 'continental' shelf of 200 to 300 fathoms depth. But in the higher latitudes, or between 60° and 40° s. lat., the depth is greatly increased. From Patagonia east to Kerguelen Island the depth generally exceeds 2,000 fathoms —in some places even 3.00O fathoms. Indeed, the depth on the GOth parallel nearly all round the

Vol. I.—Mar. '12

Pole exceeds 2,000 fathoms. South America, or rather Tierra del Fuego, is apparently linked to the Antarctic lands at Graham Land by a curving submarine ridge, which separates the Southern Atlantic from the Southern Pacific, and is only about 110 fathoms below the surface.

On the whole, the water of the Antarctic Ocean would appear to be colder than the water of the Arctic. On the surface, and down to about 50 fathoms, it is comparatively warm, though absolutely cold (29° to 30° F.). Thence the temperature gradually increases down to about 165 fathoms, where it is 35°; and this temperature is maintained down to 800 or 825 fathoms. From this level to the bottom it again sinks to about 31°. These are the results of observations made by the German deep-sea expedition in the Valdivia in 1898-9. According to the observations of the Challenger, some twenty-five years earlier, the temperature of the surface water was between 29° and 38° (according to latitude), and of the bottom 32° to 35°; and wedged in between these two layers was a colder stratum of water, with a temperature of only 28° to 32.5°. Ross, again, in 1841-3, reported a surface temperature of 27.3° to 33.6°, with an average of 29.8°—• this being in the summer.

Meteorologically, the area about the South Pole is one of low pressure, having a mean of less than 29 inches; and this vast permanent anticyclone appears to have a much wider extension in winter than in summer. The climatic conditionsdepend largely upon the wind. When it blows from the south it is clear and cold; but winds from the opposite directions bring fogs and cloud and a rise of temperature. There is continuous daylight from November to January.

In regions higher than 40° s. lat., the Antarctic plankton, or organic life of the surface, is characterized by an abundance of diatoms. Pelagic animals, such as molluscs, amphipods, copeppds, and other marine organisms, are plentiful down to 1,000 fathoms, and are not at all scarce at 2,700 fathoms. Sir John Murray asserts there are species common to both North and South Polar regions which are absent in the depths of the intervening oceans.

The southern right whale (Balaina auslralis) extends at least as far south as 50° s. lat., but it is in no sense an ice whale. There are two whales peculiar .to southern seas—the pygmy

whale (Neobalana marginatn) and a bottlenose (Hyperoodon planifrons); but these hardly extend into the Antarctic. There are possibly several Antarctic rorquals. , Four true seals are peculiar to the Antarctic— Weddell's seal (Leptonychotes Wcddelli), the sea-leopard (Ogmorhinus leplonyx), Ross's seal (Ommatophoca Rossi'), and the crab-eating seal (Lobodon carcinophagus). All are widely distributed throughout the area. No fur-seal is truly Antarctic; but it is stated that the elephantseal occurs off the coast of Victoria Land.

The most characteristic birds are the penguins, especially the emperor and the Adelie; the petrels, especially the ice, giant, and Antarctic petrels; and the Antarctic skua, which Lieutenant Prestrud's party of Amundsen's Expedition (1910-1911) saw in King Edward vn. Land. Meantime, the invertebrates are little known; but recent expeditions have taken rich hauls. Land plants are naturally very few; a grass (Aira ccespitosa) and a few mosses and lichens have been thus far described.

Much information has been collected by recent expeditions regarding the geology of the Antarctic regions. In Victoria Land sandstone has been found containing fossil plants (dicotyledons), apparently of Miocene age. In the region of Louis Philippe Land, almost at the opposite side of the circle, a marine volcanic- tuff containing (drifted) land plants of Tertiary age occurs. In the same region there are deposits containing Jurassic land plants, and fossiliferous marine beds belonging to the Jurassic and Cretaceous systems. The South Orkneys consist of Primary sedimentary deposits, chieny greywackes and conglomerates, in which a fossil graptolite has been found. Kaiser Wilhelm n. Land is apparently composed of Archaean rocks, especially granite, gneiss, and quartzite. Here, as elsewhere within the area, there also occur volcanic lavas of recent date.

See also the article on AntarcTic Exploration, and Bibliography cited there.

Antares, a Scorpii, a red star of 1.5 magnitude. It gives a banded spectrum of Secchi's third type, and forms, with a seventh-magnitude green satellite, a beautiful chromatic combination. Admitting the reality of Finlay's parallax of 0.02". this star must possess about 54O times the sun's lightpower, and appears to us in

[ocr errors][graphic]
[ocr errors][ocr errors][merged small]
[merged small][graphic][ocr errors][ocr errors][ocr errors]

Antant,

Ant-bear, either of two large, furry termite-eating animals: (l) the great ant-eater of S. America; or (2) the aard-vark of Africa.

Ant-Birds. Tropical birds of various kinds which feed partly upon ants or termites (white "ants'), but the degree to which they seek this fare seems to have been exaggerated or mistaken. All belong to a large family of small South-American insect-eating birds, named Formicariida; with reference to this characteristic. They are for the most part of subduecf colors and voice, and spend their time in shyly hunting for various small insects on or near the ground in wooded regions; but when a marching column of leaf-cutters or other migratory ants is 'abroad they will sometimes gather and prey upon it in great numbers. Resemblances in form, colors or manners, to other well-known birds, have led Europeans there to give the names ant-thrush,' 'ant-shrike' and 'ant-wren' to particular sriccies. Similarly the small, brilliant ground-searching pittas of the tropical East arc there called ) ant-birds,' though they rarely if ever take this food.

Aiit-i-nd-r, a term applied to several unrelated mammals of similar -habits and diet. The true ant-caters are members of the order Edtntata, and are confined to S. America. The largest, the great ant-eater or tamanoir (Myrrttccophaga iubala\ reaches a lengtn of 4 ft., exclusive of the large, bushy tail, and has the face prolonged into a long, tubular snout. Teeth arc entirely absent, and the long, flexible tongue is covered with sticky saliva by which the ants are caught when the tongue is thrust into their unroofed masses. The fore limbs are furnished with powerful claws. which are used in tearing open the nests of termites, or 'white ants/ on which.the animals chiefly feed. It is terrestrial anil lives in dense

forests, but does not burrow; and its long claws and great strength make it a formidable antagonist. Related forms are the arboreal tamandua and the little ant-eater (Cychturus), the latter subsisting mainly on the honey-comb and grubs of wasps. The scaly ant-, eater orpangolins (q.v.) are members of the same order; as is also the African aard-vark, ant-bear,, or Cape ant-cater. The term spiny ant-eater is applied to Echidtia, and banded ant-cater to Myrmccobius (asciatus, a curious little, Australian marsupial mammal, which is chestnut-red, with white' and dark stripes on its back, and somewhat resembles the English squirrel in appearance.

[graphic][merged small]

Antecedent, in grammar, the subject to which a succeeding pronoun refers; in logic, the premise from which a 'consequent'proposition is inferred; in mathematics, the first element in a ratio—e.g.2:4 = 3:6.

Antelope, one of a group of agile, swift - footed ruminants (Bovidse), which cannot be definitely regarded as sheep, goats, or oxen. They are characterized by having slender, usually cylindrical horns, usually marked with ring-like elevations," and as a rule confined to the males. Some of these (e.g. the Alpine chamois) are structurally near the goats, and others (e.g. the African genus Alcelaphus) are far removed from them. Antelopes are typically plain animals, and are therefore specially at home in Africa, but their migration thither from the north is recent, geologically speaking. A few only of the more conspicuous antelopes can be noticed here, and further information will be found elsewhere under their several names. In the genus Alcelaphus, including the African hartebeest, blesbok, bontebok, and others, the back slopes, owing to the fact that the height at the withers is much greater than at the rump, the head is long and narrow, and the horns are lyratc and bent back at the tips. The African gnu is a near ally of these forms. In size these antelopes should be contrasted with the duikerboks, of which the smallest. is not larger than a rabbit, while the hartebeest may stand nearly 6 ft. at the withers. The saiga is one of the few antelopes which occur in Europe and Asia. In India there are relatively few ante

lopes; but the somewhat cowlike nylghau deserves mention. Related is the African genus Tragelaphus, including the beautiful harnessed antelopes, with long,, spirally-twisted horns. Another African antelope, the gcmsbok, is remarkable for its long, straight horns, present in both sexes. The eland (Orcas canna), the largest of all antelopes, is said to be rapidly disappearing. In structure and in habitat the European chamois connects the antelopes with the goats. No true antelope belongs to America, our so-called 'antelope' being a prong horn (q. v.). For S. African antelopes see works by Millais and Bryden and the writings of many sportsmen; for Asiatic, Baker, Wild Beasts and their Ways (1892); Blandford, Fauna of British India: Mammals (1888); Sclater and Thomas, The Book of the Antelopes (1896).

Ante meridiem. Sec A.m.

Antennae, or feelers, are sense organs, generally tactile, borne on the head in crustaceans, myriapods, and insects, where they are homologous with the other appendages, such as the jaws. See Insects; Crustacea.

Antenor, the Trojan counsellor who urged the Trojans to restore Helen to Mcnelaus.

Ante - Nuptial Agreement. An agreement made by a man or woman, with each other or with third parties, in contemplation of their marriage with one another. The term is most frequently applied to an agreement for trie settlement of the property of one or both the parties for their joint benefit after marriage and for that of their issue, or to an agreement between them respecting the terms on which the wife is to share in the husband's estate in the event of his death. The importance of an ante-nuptial as compared with a post-nuptial agreement lies in the fact that a .contemplated marriage is a good consideration for a promise made with reference thereto, whereas a past marriage is not, and in the further fact that at .common law the marriage, by merging the wife's legal personality in that of the husband, destroys the woman's ability to enter"into a binding contract with her husband.

Antpquera (anc. Antiquaria) tn., prov. Malaga, Spain, 27 m from Malaga. Pop. (1900) 31,609.

Anthrlla, colored circles, usually three or four in number, which surround the shadow of the observer's head when projected on a fog; seen in the Arctic regions and on mountains: also known as 'Ulloa's circle,' or as a 'glory.'

\nthelmlntlcs, remedies which kill or expel intestinal worms. Vermicides kill the worms, vermifuges expel them. For tape

« السابقةمتابعة »