GREAT SOUTHERN OCEAN, the name given to the belt of water which extends almost continuously round the globe between the parallel of 40° S. and the Antarctic Circle (66½° S.). The fact that the southern extremity of South America is the only land extending into this belt gives it special physical importance in relation to tides and currents, and its position with reference to the Antarctic Ocean and continent makes it convenient to regard it as a separate ocean from which the Atlantic, Pacific and Indian Oceans may be said to radiate. (See [Ocean].)
GREAVES, JOHN (1602-1652), English mathematician and antiquary, was the eldest son of John Greaves, rector of Colemore, near Alresford in Hampshire. He was educated at Balliol College, Oxford, and in 1630 was chosen professor of geometry in Gresham College, London. After travelling in Europe, he visited the East in 1637, where he collected a considerable number of Arabic, Persian and Greek manuscripts, and made a more accurate survey of the pyramids of Egypt than any traveller who had preceded him. On his return to Europe he visited a second time several parts of Italy, and during his stay at Rome instituted inquiries into the ancient weights and measures. In 1643 he was appointed to the Savilian professorship of astronomy at Oxford, but he was deprived of his Gresham professorship for having neglected its duties. In 1645 he essayed a reformation of the calendar, but his plan was not adopted. In 1648 he lost both his fellowship and his Savilian chair on account of his adherence to the royalist party. But his private fortune more than sufficed for all his wants till his death on the 8th of October 1652.
Besides his papers in the Philosophical Transactions, the principal works of Greaves are Pyramidographia, or a Description of the Pyramids in Egypt (1646); A Discourse on the Roman Foot and Denarius (1649); and Elementa linguae Persicae (1649). His miscellaneous works were published in 1737 by Dr Thomas Birch, with a biographical notice of the author. See also Smith’s Vita quorundam erudit. virorum and Ward’s Gresham Professors.
GREBE (Fr. grèbe), the generally accepted name for all the birds of the family Podicipedidae,[1] belonging to the group Pygopodes of Illiger, members of which inhabit almost all parts of the world. Some systematic writers have distributed them into several so-called genera, but, with one exception, these seem to be insufficiently defined, and here it will be enough to allow but two—Latham’s Podiceps and the Centropelma of Sclater and Salvin. Grebes are at once distinguishable from all other water-birds by their rudimentary tail and the peculiar structure of their feet, which are not only placed far behind, but have the tarsi flattened and elongated toes furnished with broad lobes of skin and flat blunt nails.
| Illustration: Great Crested Grebe. |
In Europe are five well-marked species of Podiceps, the commonest and smallest of which is the very well-known dab-chick of English ponds, P. fluviatilis or minor, the little grebe of ornithologists, found throughout the British Islands, and with a wide range in the old world. Next in size are two species known as the eared and horned grebes, the former of which, P. nigricollis, is a visitor from the south, only occasionally showing itself in Britain and very rarely breeding, while the latter, P. auritus, has a more northern range, breeding plentifully in Iceland, and is a not uncommon winter-visitant. Then there is the larger red-necked grebe, P. griseigena, also a northern bird, and a native of the subarctic parts of both Europe and America, while lastly the great crested grebe, P. cristatus or gaunt—known as the loon on the meres and broads of East Anglia and some other parts of England, is also widely spread over the old world. North America is credited with seven species of grebes, of which two (P. griseigena and P. auritus) are admitted to be specifically inseparable from those already named, and two (P. occidentalis and P. californicus) appear to be but local forms; the remaining two (P. dominicus and P. ludovicianus) may, however, be accounted good species, and the last differs so much from other grebes that many systematists make it the type of a distinct genus, Podilymbus. South America seems to possess four or five more species, one of which, the P. micropterus of Gould (Proc. Zool. Society, 1858, p. 220), has been deservedly separated from the genus Podiceps under the name Centropelma by Sclater and Salvin (Exot. Ornithology, p. 189, pl. xcv.), owing to the form of its bill, and the small size of its wings, which renders it absolutely flightless. Lake Titicaca in Bolivia is, so far as is known at present, its only habitat. Grebes in general, though averse from taking wing, have much greater power of flight than would seem possible on examination of their alar organs, and are capable of prolonged aerial journeys. Their plumage is short and close. Above it is commonly of some shade of brown, but beneath it is usually white, and so glossy as to be in much request for muffs and the trimming of ladies’ dresses. Some species are remarkable for the crests or tippets, generally of a golden-chestnut colour, they assume in the breeding season. P. auritus is particularly remarkable in this respect, and when in its full nuptial attire presents an extraordinary aspect, the head (being surrounded, as it were, by a nimbus or aureole, such as that with which painters adorn saintly characters), reflecting the rays of light, glitters with a glory that passes description. All the species seem to have similar habits of nidification. Water-weeds are pulled from the bottom of the pool, and piled on a convenient foundation, often a seminatant growth of bogbean (Menyanthes), till they form a large mass, in the centre of which a shallow cup is formed, and the eggs, with a chalky white shell almost equally pointed at each end, are laid—the parent covering them, whenever she has time to do so, before leaving the nest. Young grebes are beautiful objects, clothed with black, white and brown down, disposed in streaks and their bill often brilliantly tinted. When taken from the nest and placed on dry ground, it is curious to observe the way in which they progress—using the wings almost as fore-feet, and suggesting the notion that they must be quadrupeds instead of birds.
(A. N.)