38 THE CANADIAN NATURALIST. , [Feb. 



region of the Canaries, and sends a westerly branch towards the 

 West Indies. Thirdly — we have the South Atlantic current set- 

 ting from the Arctic Ocean, pouring its volumes between St. Hel- 

 ena and the main, until arriving at the northern edge of the North 

 African current at the equator, it diverges to the westward, and 

 flows into the Equatorial current which advances in a similar 

 direction to the northern coast of Brazil, and sweeping past the 

 ■coasts of Cayenne and Gruiana, bends round the Gulf of Mexico, 

 and heated in that vast cauldron to a high degree of temperature, 

 jushes with great velocity through the Florida passage, and be- 

 vcomes the celebrated Gulf Stream. Fourthly — The main current 

 of the Pacific is that known as the Peruvian current, which origi- 

 nates in the Antarctic drift current, and runs parallel with the 

 South American coast from about the fortieth degree of south lat- 

 itude to the northern shores of Mexico, whence it deviates, and 

 rushes on to the westward across the Pacific, laving the shores of 

 the whole intertropical islands until it arrives at New Guinea, and 

 Australia, where it meets the counter currents from the Indian 

 Ocean. Lastly — We have the Arctic current of the Atlantic, 

 which sets from Baffin's Bay on the west, and Spitzbergen on the 

 east side of Greenland, joining its parts at the northern extremes 

 of the latter country, and as one vast stream, running its course to 

 the Banks of Newfoundland, where it meets a barrier to its farther 

 progress in the heated waters of the Gulf Stream. 



Although the currents just enumerated include all the greater 

 passages, yet there are divers others of less magnitude and extent 

 which render service in disseminating around reproductive matter 

 for the colonization of distant positions. In the Indian Ocean, 

 for example, we have two currents running parallel with the con- 

 tinent of India, and another between the island of Madagascar 

 and the adjoining coast of Mozambique, each exerting an influence 

 on the country they pass. These, with the connecting and contra 

 currents occurring in several positions, may be supposed to repre- 

 sent in some degree that progressive motion which agitates the 

 wide expanse of ocean in diff"erent quarters of the globe. 



Haying thus far given a brief account of the positions and 

 courses of these currents, let us consider their effect upon islands 

 lying in or near their course, but far removed from any continent : 

 but as it would extend this paper to an unusual length if we 

 were to enumerate the many islands in each ocean which may be 



