1 1 2 Temperature Sections Surveyed. 



North Atlantic and North Pacific Oceans. It constitutes one of 

 the most remarkable proofs of the uniformity of laws and con- 

 ditions which determine the movements of the oceanic waters 

 from pole to pole. The pouring in of the North Pacific 

 Equatorial Current through the chain of islands which 

 separates the Sea of Magallanes from the main basin of the 

 Pacific, just as the North Atlantic Equatorial Current flows 

 into the Caribbean Sea through the Antilles — the progress 

 of the Pacific current through the southern portion of the Sea 

 of Magallanes, and the accumulation of its waters in the 

 northern and more restricted portion of this sea, as we observe 

 the circulation of the Atlantic current through the Caribbean 

 Sea and the accumulation of its waters in the Gulf of Mexico — 

 the relief of the pressure caused by this accumulation, through 

 the formation in both cases of a powerful current which forces 

 its way through the northern end of the barrier of islands and 

 joins the branch of the equatorial current which has been moving 

 northwards outside this barrier — finally, the subdivision of both 

 equatorial currents, after their encounter with the polar currents, 

 into branches, some of which continue their course into the polar 

 seas, while others bend round, and, gradually cooling in contact 

 with the currents from the north, flow down the western coasts 

 of the opposite continents in order to resume once more their 

 course in the character of equatorial currents, form two parallel 

 series of occurrences, the resemblance between which is too 

 close to be the result of mere accident. An exception to this 

 comparison may be found in the return southwards of a portion 

 of the North Pacific Equatorial Current through the Western 

 Carolines and the Pelew Islands into the Sea of Papua in con- 

 junction with the polar under-current. It is in this latter current 

 that we must seek the cause of the remarkably rapid decrease of 

 temperature in the stratum between loo and 200 fathoms which 

 forms another prominent feature of this section. The polar 



