GEOGRAPHY 685 South America. At the same time discovery in the East advanced with rapid strides. With- in 20 years from the time of Gama's arrival in India, the coasts of E. Africa, Arabia, Persia, Hindostan, and Further India had been ex- plored, and many of the islands of the great archipelago discovered. In the 16th and 17th centuries the progress of astronomical science led to a general revision of Ptolemy's tables of latitude and longitude, which had for ages been received with implicit confidence, but which more accurate observations now proved to be generally erroneous. In the 18th century many learned and laborious writers, among whom D'Anville may be particularly men- tioned, applied themselves to the rectification of the whole system of ancient geography, and to the identification of ancient with mod- ern countries, cities, rivers, mountains, and other features. The desire to discover a shorter route to India than those by Cape Horn and the cape of Good Hope led the English and the Dutch in the 16th century to make daring and persevering efforts to effect a N. E. and a N. W. passage. For a long time the opinion prevailed that the northern extremity of America terminated, like the southern, in a point or cape, by sailing around which the mariner could enter the Pacific ocean and make his way to India. The expeditions of Sir Hugh Willoughby and Richard Chancellor in 1553, of Frobisher in 1676-'8, of Davis in 1585-'7, of Barentz in 1594-'6, in search of this northern route, greatly enlarged the knowledge of the arctic regions, and es- pecially of the N. E. part of North America. So, too, in the succeeding century, a similar result followed from the voyages of Henry Hudson in 1607-11, and of William Baffin in 1612-'16. It was not till the latter part of the 18th century, however, that the great breadth of the upper part of North America became fully known from the investigations of Capt. Cook in his voyages to the Pacific. The de- termination of the distance ' from Behring strait to the E. coast of North America dis- pelled for a time all expectation of a N. W. passage ; it was supposed that the continent stretched in one unbroken mass to the pole. The discoveries of Hearne in 1771 and of Mackenzie in 1789, by showing that an ocean bounded America on the north, dispelled' these ideas, and in 1818 the attempt to effect the N. W. passage was revived by an expedition commanded by Capt. Ross. This was the be- ginning of a series of English and American expeditions to the arctic regions which have greatly advanced our knowledge of that part of the world, though without attaining the ob- ject for which they were commenced. (See ARCTIC DISCOVERY.) Early in the 17th century the Dutch, while seeking for a southern conti- nent whose existence was supposed necessary to balance the northern, discovered Australia, which they called New Holland, and explored a considerable portion of its coasts. In 1642 Tasman discovered Van Diemen's Land, or Tas- mania, as it is now called. Soon afterward he discovered New Zealand and several of the Polynesian groups. His explorations proved that New Holland was an island, and not a part of the southern continent. The famous Capt. Cook in his voyages, 1768-'79, made strenuous efforts, without success, to discover the southern continent ; but he added largely to geographical knowledge by his survey of the Pacific ocean and its innumerable islands. An expedition sent out by the United States in 1838, under command of Lieut. Wilkes, in 1842 discovered a continent within the antarctic circle, por- tions of which had been seen shortly before by the French and English navigators Dumont d'Urville and Sir James Ross. (See ANTARC- TIC DISCOVERY.) Our acquaintance with the interior of Asia has been greatly advanced within the last two centuries by Russian, Eng- lish, and French conquests, and by a multitude of travellers, prominent among whom have been the Jesuit missionaries, so that our gene- ral knowledge of that continent is tolerably complete. No great terra incognita remains, though fuller and more precise information about the vast regions known as Tartary is much to be desired. The travels of Humboldt, of Lewis and Clarke, and of Fremont have en- larged our acquaintance with the interior of the American continent ; and during the last few years much light has been thrown upon it by the various exploring expeditions sent out by the government, and especially by companies of professors and students from our colleges. The interiors of Australia and of Africa are still only partially known. Much has been done for the exploration of the former by Sturt, Eyre, Leichardt, Stuart, McKinlay, Landsborough, Burke, the brothers Gregory, and others; while in Africa a host of travellers have struggled for a century past to penetrate the mystery which envelops that great division of the globe. Foremost among the African explorers have been James Bruce, Mungo Park, Major Denham, Lieut. Clapper- ton, Richard Lander, Captains Burton and Speke, Dr. Livingstone, Dr. Earth, Heuglin, and Sir Samuel Baker. Great additions to our knowledge of the countries on the upper Nile have been made by expeditions sent by the pasha of Egypt, which have penetrated far beyond the region so long assigned on our maps to the mountains of the Moon. These expeditions and the researches of Barth, Burton, Livingstone, Baker, and the mission- aries Rebmann and Krapf, have left in ob- scurity only a portion of that part of Africa which lies between lat. 10 N. and 10 S., and Ion. 12 and 27 E. Dr. Livingstone at the time of his death was endeavoring to penetrate this region. The remarkable progress of geograph- ical discovery during the present century may be thus briefly summed up: Northern AfU has been traversed by the expeditions sent out by the Russian government; the great neld
