Vague reports of a great ocean lying beyond China were current in Europe as early as the period of Arabian supremacy in learning. Indeed an Arab merchant named Sulaiman, who visited China in the 9th century, declared that he had sailed upon it. But for several hundred years the reports continued so uncertain, and were so loaded with the wild extravagance of travellers’ tales of the period, that it is difficult to get at the facts from which they probably took their origin. During the 13th and 14th centuries Marco Polo arid his successors travelled far to the East and came to an ocean of the extent of which they were ignorant, but they partially explored its western coasts. The East was the region towards which all the commerce and enterprise of the Middle Ages tended, and it was the hope of finding a safer and shorter sea route to India that led the Spanish court in 1492 to furnish Columbus with a fleet for the exploration of the Western Ocean. Although convinced of the spherical form of the earth, he greatly under-rated its size, and, accepting the popular estimate of the great breadth of the Asiatic continent, he set out on his voyage confident of soon reaching “the Indies.” The glowing descriptions of his discoveries in that strange new world of the West that' rose up before him to bar his advance immediately attracted the attention of adventurous Spanish mariners. Headed by Columbus himself, they cruised intrepidly amongst the Caribbean Islands, still lured by the hope of discovering some western passage to the coveted East. Columbus found that what he at first considered a labyrinthine archipelago was a continent of vast extent, but not Asia, and he died without knowing what lay beyond. Spain and Portugal were the rival maritime powers at that time, and both took up the search for new countries with great ardour. Pope Alexander VI., in 1493, fearing that the two nations would quarrel over their colonies, assigned all the new lands that might be discovered west of the Azores to Spain, and all east of those islands to Portugal. The Portuguese accepting the gift followed Vasco da Gama in opening up the road to India by the Cape of Good Hope, and pushed forward their trading and piratical excursions into the west Pacific far beyond the Spice Islands. The Spaniards confined themselves to the New World, visiting, naming, and plundering the West India Islands and the headlands of Central America. On the 29th of September 1513 Vasco Nunez de Balbao, the leader of a Spanish party exploring the Isthmus of Panama, saw, from the summit of a mountain, a vast ocean stretching to the west—the very ocean of whose existence Columbus was certain, and which he had so long tried vainly to discover. Because he first saw it on Michaelmas day, Balbao named it the Golfo de San Miguel. Magellan, following the east coast of America farther to the south than any previous explorer, sailed on, in spite of terrific storms, until he found the strait which now bears his name, and, steering carefully through it, on the 27th of November 1520 he swept into the calm waters of that new sea on which he was the first to sail, and which he named the Mar Pacifico.

The victories of Cortez in Mexico about the same date opened the way for the exploration of the west coast of America, where Pizarro’s conquest of Peru in 1526 gave the Spaniards a firm footing. From this time an intermittent trade sprang up between Europe and the Pacific through Magellan Strait, and latterly round Cape Horn. Before long English fleets, attracted more by the prospects of plundering Spanish galleons than of discovering new territories, found their way into the Pacific. Sir Francis Drake, like Balbao, saw the ocean from the Isthmus of Panama. He entered the Pacific in September 1577, being the first Englishman to sail upon it; some months later he sailed across it to the Moluccas. Alvaro de Mardana, who preceded him, had discovered the Solomon Islands in 1567.

Tasman, Roggewein, Dampier, and other explorers of the 17 th century discovered Australia, New Zealand, Tasmania, and many smaller groups of islands. During the 18th century the voyages of Anson, Bass, Behring, the two Bougainvilles, Broughton, Byron, Cook, La Pérouse, and many more practically completed the geographical exploration of the Pacific Ocean. In the beginning of that century the Pacific had a curious fascination for commercial speculators, and the ill-fated Scottish colony founded at Darien in 1698 seemed only to prepare the way for the English South Sea bubble that burst in 1720. All the navigators who explored these seas believed in the existence of a north-west passage between the Atlantic and Pacific, and made attempts to find it; but its discovery baffled all enterprise until 1850, when Maclure proved that there was such a channel, but that the ice prevented its being of any commercial utility. In the present century D’Entrecasteaux, Krusenstern, Beechy, Fitzroy, and Bennet have taken the lead amongst geographical.explorers in the Pacific, although the ranks contain many names scarcely less worthy of remembrance. Within recent years several purely scientific exploring expeditions and British surveying vessels have examined the Pacific, investigating its depth, the nature and form of the bottom, the temperature of the water at various depths and its density, as well as the marine fauna and flora. Of those expeditions the voyages of the “Challenger,” “Gazelle,” and “Tuscarora” are the most important. Extent.— The Pacific Ocean is bounded on the N. by Behring Strait and the coasts of Russia and Alaska, on the E. by the west coasts of North and South America; on the S. the imaginary line of the Antarctic Circle divides it from the Antarctic Ocean, while its western boundary is the east coast of Australia, the Malay Archipelago separating it from the Indian Ocean, and the eastern coasts of the Chinese empire. Some modern geographers place the southern limit of the Atlantic, Pacific, and Indian Oceans at the 40th parallel, and name the body of water which surrounds the earth between that latitude and the Antarctic Circle the Southern Ocean.

Although differing from the Atlantic in its general form, being more nearly land-locked to the north, the Pacific resembles it in being open to the south, forming, in fact, a great projection northwards of that vast southern ocean of which the Atlantic is another arm.

The Pacific is the largest expanse of water in the world, covering more than a quarter of its superficies, and comprising fully one-half of its water surface. It extends through 132 degrees of latitude, in other words, it measures 9000 miles from north to south. From east to west its breadth varies from about 40 miles at Behring Strait, where Asia and America come within sight of each other, to 8500 miles between California and China on the Tropic of Cancer, and to more than 10,000 miles on the Equator between Quito and the Moluccas, where the ocean is widest. The area has been variously estimated at from 50,000,000 to 100,000,000 square miles; but,defining its boundaries as above, Keith Johnston, from careful measurements, estimated it, with probably a near approach to the truth, at 67,810,000 square miles.

Coasts, Seas, <l·c.— The coast-line of the Pacific and Indian Oceans, taken together, only amounts to 47,000 miles; that of the Atlantic alone measures 55,000, the smaller ocean more than making up for its less extent by its numerous inland seas and inlets of smaller size. Speaking broadly, the eastern boundary of the Pacific is rugged, barren, mountainous, and singularly free from indentations, while its western shores are low, fertile, and deeply indented with gulfs and partially enclosed seas. Behring Strait unites the Arctic Ocean with the Sea of Kamchatka, or Behring Sea, which is bounded on the east by the irregular, low, swampy shores of Alaska, and on the south by the Alaskan peninsula and the Aleutian Islands. Along British North America the coast is rugged, rocky, considerably indented, and, between the parallels of 50° and 60° N. lat., fringed with islands. The largest of these are Vancouver Island in the Gulf of Georgia, Queen Charlotte Island, Prince of Wales Island, and the islands of King George III.’s Archipelago. The Gulf of California runs northwards in the Mexican coast, reaching from 23° to 32° N. lat. It is the one important inlet on the whole west coast of America,—the only others which are worth naming being the Gulf of Panama and the Gulf of Guayaquil. The Mexican shore is low, and contrasts with the coasts to the north and to the south, which are generally steep and rocky, though there are occasional sandy beaches in Peru and Chili. The breadth of the plain between the Rocky Mountains and the sea gradually diminishes towards the south, and the mountain chain of the Andes runs close along the west coast of South America to the very extremity of the continent.

A series of volcanoes, active and extinct, runs round the Pacific, commencing at Cape Horn, passing along the Andes and Rocky Mountains, crossing from the American continent by the Aleutian Islands to Kamchatka, and thence southwards by Japan and the East Indian Archipelago to New Zealand. Earthquakes are frequent all along this line.

There are few islands near the American coast north of Patagonia, and these are small and unimportant; but south of the 40th parallel there is a complete change. The end of the continent seems as if it had been shattered; there are abrupt bays and jagged chasms; archipelagos of small islands rise up in splintered fragments along the shore. The Strait of Magellan forms a tortuous channel between the mainland and the rocky storm-beaten islands of Tierra del Fuego.

The coast-line on the Asiatic side is longer and greatly diversified. In the north the Sea of Okhotsk is cut off from Behring Sea by the peninsula of Kamchatka, from the extremity of which a chain of islands extends to the borders of the Antarctic Ocean. These islands are of all sizes, ranging from small islets to the island continent of Australia. The island chain hangs in loops along the Asiatic coast, each loop including an almost land-locked sea. These partially enclosed seas are more or less completely cut off from the general oceanic circulation, and they consequently differ considerably from the open ocean as regards the temperature of the water, specific gravity, fauna and flora, and nature of the deposits. The Kurile Islands run from Kamchatka to Japan, cutting off the Sea of Okhotsk. The great Japanese Islands, with Saghalien to the north and the Chinese coast on the west, enclose the Sea of Japan, leaving it in communication with the Sea of Okhotsk by the Channel of Tartary to the north, with the ocean on the west by the Straits of La Pérouse and Sangar, and on the south by the Straits of Corea. The Yellow Sea runs into the Chinese coast, and is divided from the Sea of Japan by the peninsula of Corea. The China Sea, with the two great gulfs of Tonquin and Siam, is marked off from the Indian Ocean by the peninsula of Malacca—remarkable because it runs in the same direction as the other two peninsulas of the Pacific, Kamchatka and Corea—and the islands of Sumatra and Java, while Borneo and the Philippine Islands separate it from the Pacific. Between the south coast of China and the north of Australia the East Indian Archipelago cuts up the ocean into a network of small seas and narrow channels. The seas are named the Celebes, the Banda, the Sulu, the Java, the Flores, and the Arafura. The more important of the sea passages between the islands are the Straits and Channel of Formosa, which lead northward from the Pacific to the China Sea; the Strait of Macassar between Borneo and Celebes; Molucca Passage between Celebes, the Moluccas, and Jilolo; and Torres Strait between New Guinea and Australia. The east coast of Australia is, as a rule, steep and rocky; there are few inlets, and none of them compare in size with the Gulf of Carpentaria on the north coast. Moreton Bay and Port Jackson are two of the best harbours, and as a haven the latter has few equals in the world. The Great Barrier Reef lies off this coast for a length of more than a thousand miles, the distance between it and the shore varying from 60 to 100 miles. Bass Strait separates Australia from Tasmania on the south; and the two main islands of New Zealand, separated by Cook Strait, lie to the southeast of the continent. The Gulf of Hauraki, the Bay of Plenty, and Pegasus Bay are the chief inlets in these islands.

River-System.— The drainage area of the Pacific Ocean is estimated at 8,660,000 square miles, while that of the Atlantic amounts to more than 19,000,000; the chief reason for this disparity is that only half a million square miles of the American continent are drained into the Pacific, the remaining six and a half millions being connected with the Atlantic river-system, and it is estimated that only one-seventh of the area of the Asiatic continent drains into the Pacific Ocean. The huge wall of the Andes practically reduces the Pacific rivers of South America to the rank of mountain streams; the Biobio and the Maypu in Chili are the only ones exceeding 100 miles in length,— the former having a course of 180, the latter of 160 miles. The Rocky Mountain chain, which forms the watershed of North America, runs parallel to the Pacific coast at a distance of about 1000 miles, and the Cascade and minor ranges which skirt the shore are broken through in several places to give passage to rivers that are, in some cases, of considerable size. The Colorado rises in the State of that name, at the base of the Rocky Mountains, flows southwest through Utah and Arizona, and falls into the head of the Gulf of California. Its course measures about 1100 miles, and it drains a rugged and barren area of 170,000 square miles. California has only one river, the Sacramento, 420 miles long. The Oregon (or Columbia) is formed by the union of two streams rising in the Rocky Mountains, one in British Columbia, the other in Idaho. It is a swift-flowing river, full of rapids and cataracts, and, though it is only 750 miles long, the area which it drains is greater by one-seventh than that drained by the Colorado. The ebb and flow of the tide are perceptible for a hundred miles from the mouth of the Oregon, and the river is navigable for that distance. The Frazer, which has a length of 600 miles, flows southward through British Columbia from the Rocky Mountains, and enters the sea in the Gulf of Georgia opposite Vancouver Island, carrying off the rainfall of 98,000 square miles. The northern limit of the American mountain chains is marked by the rise of the great river Yukon, which traverses Alaska; and, after a run of more than 2000 miles, it enters Behring Sea opposite the island of St Lawrence. Its tributaries have not been fully explored, so the area which they intersect is unknown, but probably it is very large.

The Asiatic division of the Pacific river-system is very much more extensive than the American, and includes many streams of great size and of considerable commercial importance. In the north the Amur is more than 2000 miles long, and it receives many tributaries, which rise on the north in the Stanovoi mountains, and on the west and south on the borders of the great table-land of the Gobi, the central Asiatic desert; altogether its basin measures nearly 900,000 square miles. The Hoang-ho (Hwang-ho or Whang-ho) and the Yangtze-keang both rise near the Kuen-lun mountains of Tibet amongst the extensive terraces which form the eastern slope of the great table-land of Central Asia. The Hoang ho has a length of 2600 miles, and in its course it sweeps in a northerly curve close to the In-Shan mountains; then, after being crossed repeatedly by the Great Wall of China, it turns sharply to the south, and finally runs due east into the Yellow Sea. The Yangtze-keang follows a southward direction from its source, but ultimately turns to the north-east and enters the Yellow Sea not far from the mouth of the Hoang-ho. It is one of the longest rivers in the world, for, including its windings, it measures 3200 miles from its source to the sea. These two rivers drain more than a million and a quarter square miles; and it is principally owing to the large amount of suspended matter which they carry down that the sea into which they fall is called the Yellow Sea. The other rivers of importance are the Choo-keang, the Mekong, and the Menam. The last two run into the Gulf of Siam, after watering the peninsula of Siam and Cochin China. Few rivers enter the Pacific on the east coast of Australia, and in consequence of the proximity of the mountains to the shore they are short and unimportant.

Atmospheric Pressure and Prevailing Winds.— When the mean atmospheric pressure for the year over the entire surface of the world is considered, it is found that there are two broad belts of high pressure which encircle the globe, one on each side of the equator. There is a wide area of slowly diminishing pressure between them, including a narrow central band along which the barometric readings attain a minimum. Two other regions of low pressure surround the poles, and extend to a considerable distance. That around the North Pole is connected with an area of still lower pressure over the North Pacific, and there is another permanent depression, which is even deeper, in the vicinity of Iceland. Atmospheric pressure is the fundamental meteorological phenomenon, and the mean pressure for the year affords a clue to the cause of all such regular and continuous phenomena as trade winds and ocean currents, and to the distribution of temperature. Similarly a study of the isobars at different seasons throws light upon all periodical occurrences in the way of winds and currents.

A low barometer is always accompanied by a high percentage of atmospheric aqueous vapour; consequently the equatorial belt of continuous low pressure is a region of almost continuous rain, excessive cloud, and constant calm or light variable winds. The effect of a difference in atmospheric pressure being established between two places is to produce a flow of air from the region of high towards that of low pressure, and the winds in their turn largely determine the surface movements or drift currents of the ocean. The region of calms between the north and south trades in the Pacific is both narrower, more irregular, and less clearly marked than the corresponding belt in the Atlantic. In the East Pacific it lies, at all seasons, considerably north of the equator; but during the southern summer it is found south of the line in the western parts of the ocean, and disappears entirely in the northern summer, as the calms of the Indian Ocean do also. The reason of the southern position of the west end of the calm belt seems to be the simultaneous occurrence of low atmospheric pressure in the interior of Australia and an exceptionally high barometer in Asia. In the southern winter the depression over Asia and the increase of pressure over Australia form an unbroken barometric gradient, and the result is that the calms are replaced by a southerly breeze of great regularity. The region of calms included between the zones of the two trade winds, and towards which they blow, is not the only one with which they are associated; for the opposite meteorological conditions that characterize the northern border of the north-east trades and the southern margin of the southeast winds produce two fringing bands of calms. These regions are characterized by a high barometer, a sunny sky, and occasionally sudden squalls,—contrasting with the depressed barometer and dull, wet weather of the equatorial region. In January the low atmospheric pressure over the North Pacific produces winds which affect the climatological conditions of the shores in very different ways. At Vancouver Island the prevailing wind is southwest, and consequently the winter on the shores of...