360 PHYSICAL GEOGRAPHY. 



those described by Ptolemy as growing in India. From the inhabitants of the Azores he 

 learnt that trtmks of huge pine-trees had been cast upon the shores, of a species different 

 to any that grew upon the islands ; while, towards the close of the fifteenth century, the 

 bodies of two dead men had been drifted to the island of Flores, whose features pro- 

 claimed them to belong to an unknown race. These circumstances contributed to con- 

 firm Columbus in his- theory respecting the existence of a western continent, and 

 strengthened his purpose to venture upon the untracked waste of waters in order to 

 reach it. After the commencement of his great undertaking, when day after day nothing 

 had been seen but a shoreless horizon, and hope had nearly expired in his own breast, 

 while his crew were on the verge of open rebellion, the effect of the oceanic currents 

 restored his confidence, and allayed their clamours. Herbage, fresh and green as if 

 recently plucked, floated by. A branch of thorn, with berries on it, appeared ; a reed was 

 picked up, and a staff artificially carved, significant intimations that an inhabited land 

 lay before the adventurers, which was at length revealed to their gaze, and terminated 

 for ever the mystery which had res'ted upon the western flood. Upon his second voyage, 

 Columbus found, near one of the islands, to which the Spaniards gave the name of 

 Guadaloupe, the stern-post of a European vessel, the fragment of some wreck which 

 had been borne in a contrary direction across the Atlantic. The preceding facts are 

 doubtless referable to the action of the equatorial current and the gulf stream. Previously, 

 the inhabitants of the Canaries had considered the vegetable productions thrown upon 

 their shores as coming from the enchanted isle of St. Borondon, which, according to the 

 reveries of the pilots, and certain legends, was placed towards the west in an unknown 

 part of the ocean, enveloped with eternal fogs. 



It is little more than half a century since the oceanic currents began to be accurately 

 investigated. We are indebted to M. Rossel, Captain Sabine, and Major Rennell, for 

 the principal part of the information which has been collected concerning them. Though 

 tolerably well acquainted with their site, direction, and velocity, the causes in which they 

 originate are not thoroughly understood. In all probability they are chiefly due to the 

 influence of permanent winds, to a difference iif . temperature or saltness between two 

 parts of the sea, to the annual melting of the polar ice, to the unequal evaporation 

 which the surface of the ocean experiences in high and low latitudes, and to the greater 

 velocity with which the equatorial regions are carried round in the daily rotation of the 

 globe. The sea-currents have been compared to the continental rivers, and both exhibit 

 the phenomena of volumes of water moving in a certain direction, but in extent of surface 

 and depth they are utterly disproportionate ; and if the former were transferred to the 

 land, they would constitute great inland seas, or arms of the ocean. 



There are two great currents flowing from the poles towards the equator, north and 

 south, which preserve their direction through a considerable space. The drifting of the 

 ice from the polar regions into the temperate seas, on each side of the line, evidences the 

 existence of streams following that course. The north polar current appears to strike 

 the shores of Asia, and, passing round the north cape of Europe, it crosses the upper 

 part of the Atlantic, running to the south-west till it reaches the east coast of Greenland. 

 It then traverses the narrow sea between that country and Iceland, turns round Cape 

 Farewell, the southern extremity of Greenland, and proceeds northward into Davis's 

 Strait. It follows the eastern side of the strait as far to the north as Holsteinborg, in 

 latitude 67, where, from causes of which we are ignorant, it abruptly turns to the west, 

 and strikes the opposite shore at Cape Walsingham. From thence its course is southward 

 to Labrador, and south-east to the north bank of Newfoundland, where it mingles with 

 the gulf stream, which will hereafter be noticed. The breadth of the arctic current is 

 in some places from 250 to 300 miles. Its velocity varies, in different parts of its course, 



