in the Air and in the Sea. 177 



phenomenon is often produced at coasts by the action of the 

 wind; and those who have sought a sea-bath will remember 

 that with a land-breeze the water is always colder than with a 

 sea-breeze. The former removes the warmed superficial water 

 from the coast, by which the colder water beneath is brought to 

 light. The sea-breeze, on the contrary, drives to the shore the 

 water which has been warmed on the surface of the sea. Wl at 

 the wind does in this case may well be brought about in a 

 higher degree by a permanent sea-current. In the depths, 

 even in the northern hemisphere, the polar currents appear to 

 be directed to the south-east. This is demonstrated by the 

 many icebergs which, near Newfoundland, cut through the 

 Gulf-stream in that direction. Dana's chart of the isothermal 

 lines of the sea-surface in the coldest month *, on which the dis- 

 tribution of the corals is given, permits us also to draw a similar 

 conclusion. The polar limit of the coral zone, both in the 

 Atlantic and in the Pacific, is (probably on account of the water 

 being too cold) about 10° nearer the equator on the east side 

 than on the west side of the same ocean. It is interesting that, 

 according to this chart, the northern boundary of the corals is 

 10 degrees more to the north in the Pacific than in the Atlantic 

 Ocean. The reason is probably to be sought in the fact that the 

 Atlantic forms almost the only discharge, and the main supply, 

 of the north polar basin. 



The alternating warm and colder strips of water in the Gulf- 

 stream, as well as in the Kurosiwo, seem to us to favour the 

 idea that the force which carries away from the coast the entire 

 current eastwards is not constantly of equal strength, but, so to 

 speak, has a reflex action — which perfectly corresponds with our 

 hypothesis, according to which, in the middle latitudes, the force 

 of the ebb-current must on the whole take the upper hand, but, 

 through the westward-directed force of the flood-current, may 

 be subject to periodical interruptions. 



L. von Schrenk, Member of the Academy of Sciences of St. 

 Petersburg, has recently, in a very interesting work (Stromungs- 

 Verhaltnisse im Ochotskischen una 1 Japanischen Meere), pointed 

 out that in the Yellow, as well as in the Japanese and partially 

 in the Ochotsk Sea, the temperature of the water is constantly 

 lower at the east coasts of the continent and the islands than at 

 the west coasts. We see in this a proof that in these inland seas 

 there is the same tendency of the water to move eastwards, and 

 that thereby the upper warmer water is accumulated at the east 

 side of the sea or at the west coast of the land. In the 

 White Sea also, and the Varan ger Fjord in North Lapland, 

 the temperature of the water is higher in the eastern parts than 

 * Stieler's Hand-Atlas, 1867, No. 9, Carton. 



Phil. Mag. S. 4. Vol. 48. No. 317. Sept 1874. N 



