CLIMATES OF THE OCEAN. 3O5 



upon liim also, that every hill and valley, with the grass upon its 

 sides, have each its offices to perform in the grand design. 



882. March is, in the southern hemisphere, the first month of 

 autumn, as September is with us ; consequently, we should ex- 

 pect to find in the South Atlantic as large an area of water of 80° 

 and upward in ]\Iarch, as we should find in the North Atlantic for 

 September. But do we ? By no means. The area on this side 

 of the equator is nearly double that on the other. 



883. Thus we have the sea as a witness to the fact that the 

 winds (§ 327) had proclaimed, viz., that summer in the northern 

 hemisphere is hotter than summer in the southern, for the rays of 

 the sun raise on this side of the equator double the quantity of sea- 

 surface to a given temperature that they do on the other side ; at 

 least this is the- case in the Atlantic. Perhaps the breadth of the 

 Pacific Ocean, the absence of large islands in the temperate re- 

 gions north, the presence of New Holland with Polynesia in the 

 South Pacific, may make a difference there. But of this I can 

 not now speak, for thermal charts of that ocean have not yet been 

 prepared. 



884. Pursuing the study of the climates of the sea, let us now 

 turn to Plate VI. Here we see at a glance how the cold waters, 

 as they come down from the Arctic Ocean through Davis's Straits, 

 press upon the warm waters of the Gulf Stream, and curve their 

 channel into a horse-shoe. Navigators have often been struck 

 with the great and sudden changes in the temperature of the wa- 

 ter hereabouts. In the course of a single day's sail in this part 

 of the ocean, changes of 15°, or 20°, and even of 30°, have been 

 observed to take place in the temperature of the sea. Tlie cause 

 has puzzled navigators long, but how obvious is it now made to 

 appear ! This " bend" is the great receptacle of the icebergs which 

 drift down from the north ; covering frequently an area of hund- 

 reds of miles in extent, its waters differ as much as 20°, 25°, and 

 in rare cases even as much as 30° of temperature from those about 

 it. Its shape and place are variable. Sometimes it is like a pen- 

 insula, or tongue of cold water projected far down into the waters 

 of the Gulf Stream. Sometimes the meridian upon which it is 

 inserted into these is to the east of 40°, sometimes to the west 



