Page:The New International Encyclopædia 1st ed. v. 14.djvu/851

* OCCUPANCY. 723 OCEAN. marks, which is aciiuiicil by a person using suc-li marks to imlicate his ownership of certain articles, or of certain Imsine-^s. The acquisition of title to land hy occupancy is also recognized by the law. Laud left bare by the gradual action of the sea, or deposited by ■ a river, is acquired by occupancy. While this country was a colony of Great Britain, the owner- ship of land was held to be vested in the Crown, and individual titles to land were derived from the Crown. Since the separation of the colonies from Cireat Britain, titles are derived from the grant of the United States or the individual States. The right of the discoverer of uninhabit- ed lands to assume jurisdiction over them is to be referred to the same general principle of title by occupancy. See I!e.l Property; Title; and consult the autliorities there given. OCCUPATION NEUKOSIS. A nervous con- dition characterized by a partial paralysis due to excessive fatigue of a set of muscles which have been constantly used by a neurasthenic; muscle- tire. Among occupation neuroses are chorea scriptorum, or writer's cramp, telegrapher's cramp, etc. For discussion of these diseases, see Neurosis. OCEAN (OF. ocean, Fr. ocian, from Lat. oct'diius, from Gk. ixeavdi;^ okeanos, ocean; con- nected with Skt. aiayana, ocean, from Ci, toward -)- si, to lie). The great e.xpanse of salt water occupying the larger depressions of the earth's surface. With the rivers and lakes it con- stitutes the water envelope or hydrosphere be- tween the gaseous atmosphere and the solid litho- spliere. Continental lands lie mostly in one hemisphere and may be regarded as large islands and peninsulas, while the ocean is a continuous w'ater body communicating throughout its entire area. The relative proportion between the land and water surfaces has not been accurately de- termined, as there are still large unexplored areas in the Arctic and Antarctic regions; but, using the proportion for the known parts of the earth, it is estimated that the ocean covers 72 ])er cent, of the entire surface, or approximately 142,000.000 square miles. With an estimated average depth of two miles the ocean's volume is 2S4.000,000 cubic miles, or -jij of the earth's volume. Divisions of the OcEA.>f. The continents which are massed as great triangles within the hemisphere having Southern England for its pole separate the included portion of the hydrosphere into three broad arms — the Atlantic Ocean, be- tween America and Europe-Africa ; the Pacific Ocean, between America and Asia-Australia; and the Indian Ocean, between Asia-Australia and Africa. Of these the Atlantic and Pacific com- municate at their northern extremities through the Arctic Sea, which may be regarded as an extension of the Atlantic basin. The three oceans are further divided into northern and southern parts by the equator, but this division is conven- tional and not based upon physical grounds. Snutliward. beyond the limits of the continents, they open out into a. vast expanse of shoreless water to which the name Southern Ocean may he conveniently given, the Antarctic Ocean being restricted to the area within the Antarctic Circle. The borders of the ocean are often partially shut in by chains of islands, or they form deep re- entrants into the continental lands, and such portions may have distinctive physical features. The mediterraneans, illustrated by the classic Mediterranean and the Gulf of ilexico, are in- closed seas, communicating with the ocean only by narrow passages; their depths range from 1000 (o 2000 fathoms and over limited areas even exceed the latter tigun'. .Marginal or fringing seas, partially inclosed liy island groups, include waters of great depth like the Yellow Sea and the Japan Sea, and shallower bodies like the North Sea. Deep reentrants on continental bor- ders with broad openings toward the main ocean are illustrated by the Ray of Biscay and the Gulf of Guinea. The Ocean Floor. The ocean basins are vast depressions, whose surface rises and falls in gentle undulations. Throughout most of its extent the bottom lies at depths exceeding 2000 fathoms, and there are many depressions or 'deeps' lying below 3000 fathoms. The greatest depth yet re- ported is 5269 fathoms, or ai.OU feet, in the Pacific near the island of Guam. Soundings of 5155 fathoms and 5147 fathoms have been ob- tained in the same ocean, while the greatest known depth of the Atlantic is 4501 fathoms off the coast of Porto Eico. In the deeper or pelagic regions the floor consists of soft oozes, formed from the calcareous shells of minute animals living near the ocean surface, and from volcanic dust. The most widespread deposit is globigerina ooze, an accumulation of fossil easts of forami- nifera. When the depths exceed 2500 fathoms, however, the calcareous shells are dissolved by the water and there remain only the siliceous i-emnants and volcanic materials which accumu- late very slowly over the floor as red clay. On the borders of the continents, the ocean some- times overlaps the laud in a broad belt of shal- low water whose floor is commonly called the continental shelf; here the depths do not often exceed 100 fathoms for considerable distances off shore, and the bottom consists of sand and cla,vs that have been derived from the adjacent land surface by the erosive and transporting ac- tion of rivers. The littoral islands are mostly located on such platforms, which are prominent on the eastern coast of America, the western coast of Europe, and the southwestern coast of Asia. The deeper ocean is almost free from large islands, although by volcanic activity many small islands have been built up from great depths, as in the South Paciflc. See Deep-Se.v Exploration. Ocean Water. By the continuous process of interchange between the surface waters of the land and the ocean, the latter has become a de- pository of vast quantities of mineral matter that have been dissolved out of rocks through the agency of springs and streams. The principal constituents of sea-water are the more soluble salts — the chlorides and sulphates of the alkalies and alkaline earths. The less easily soluble com- pounds, although playing a much more important rrde in the formation of rocks, are present in sea- wnter in only minute quantities. On the average 100 parts of water contain ."^.S parts of solid ma- terials whose composition is about as follows: Sodium chloride, 77.76 per cent.: magnesium chloride. 10.88 per cent.: magnesium sulphate, 4.74 per cent.: calcium sulphate, 3.60 per cent.; potassium sulphate, 2.46 per cent; magnesium