TIDES AND OCEANIC HIGHWAYS. 361 



from eight or nine to fifteen or sixteen miles per day. The icy masses it bears along are 

 supposed to be about two months in making the before-mentioned circuit from Cape 

 Farewell to the coast of Labrador. We are not so familiar with the antarctic or south 

 polar current, but have similar evidence of its action in the transportation of the ice from 

 high to low latitudes, where its course is checked by a counter stream passing westward 

 by the Cape of Good Hope and Cape Horn. Various circumstances operate to put these 

 streams in motion. The greater intensity of the centrifugal force at the equator, which 

 is the result of the earth's rotation, and the greater evaporation of the sea between the 

 tropics, owing to the powerful heat of the torrid zone, must necessarily produce a move- 

 ment of the waters from the poles towards the equator, in order to restore the equilibrium 

 which the preceding causes are perpetually destroying. It is however a singular fact, 

 only recently ascertained, with reference to the arctic current, and quite impossible to 

 explain at present, that it appears to be annually suspended for about three months, from 

 the middle of October to the middle of January ; and no perceptible evidence whatever 

 of its action at that period is found at Cape Farewell, as at other seasons, in the accumu- 

 lation of ice around it. Upon the inhabitants of Iceland this great oceanic stream con- 

 fers no unimportant benefit in the drift timber which it casts upon their shores, affording 

 them an abundant supply of wood for fuel, and for the construction of boats, their own 

 forests having been improvidently exhausted. The immense quantity of it, amounting to 

 whole forests of pines and firs, has attracted much attention ; and it has been deemed 

 difficult to explain from what country it can have been derived. Captain Parry found a 

 large quantity thrown by the sea upon the coasts of Spitzbergen ; and Crantz informs us, 

 that the masses of floating wood thrown upon the island of Jan Mayew often equal the 

 whole of the island in extent. The most probable solution of its origin is, that the rivers 

 of Northern Asia carry the timber of the Siberian forests into the Arctic Ocean, from 

 whence it is borne by the current to mitigate the cold of the Icelandic winter. It was 

 the north polar current that presented the most formidable obstacle to Parry in his 

 attempt to reach the pole by means of boat-sledges and reindeer, and led to the 

 failure of the daring enterprise. Having travelled over the frozen surface of the 

 deep to nearly latitude 83, which seemed to be the utmost limit of animal life, the adven- 

 turers found that when, according to their reckoning, they had made ten or eleven miles 

 of direct northing, they had actually gone four miles to the south, owing to the current 

 carrying the snow-fields in that direction. An invisible power was thus continually 

 undoing what they were labouring to accomplish, which rendered the success of the expe- 

 dition hopeless. 



The grandest movement of the ocean in the form of a stream-current proceeds from 

 east to west, on each side of the equator, and is therefore called the equatorial or tropical 

 current. In the Pacific Ocean it sweeps westward from the coast of Peru in one immense 

 volume, till, reaching New Holland and the islands of the Asian Archipelago, it is broken 

 into smaller branches of different divergence ; and hence the numerous and variable cur- 

 rents prevailing in the Indian Ocean, which render the navigation so dangerous. A great 

 branch passes to the south of New Holland, preserving a generally uniform westerly 

 direction, till it is obstructed by the island of Madagascar and the east coast of Africa, 

 from which it glides off to the south round the Cape of Good Hope. In the Atlantic 

 Ocean the equatorial current is very perceptible, the westward flow of the waters - com- 

 mencing in the Bay of Benin and at the Canaries, and proceeding across its basin to the 

 opposite shore of America, where, off Cape St. Roque, on the Brazilian coast, it is sepa- 

 rated into two branches. One branch, called the Brazil current, proceeds southward 

 along its coast- line, crosses the mouth of the La Plata, passes through the Straits of 

 Magalhaen and round Cape Horn, and mingles with the westward flow of the Pacific. 



