§ 731-733. THE CLIMATES OF THE SEA. 393 



tember. But do we? By no means. The area that is covered 

 on this side of the equator with water at 80° and upward is nearly 

 double that on the other. Thus we have the sea as a witness to 

 the fact which the winds had proclaimed, viz., that summer in the 

 northern hemisphere is hotter than summer in the southern. 



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

 Sudden changes in tuHi to Plate VI. Hcrc wc scc at a Qflance how the 



the Avater thermom- r> i * • 



eter. cold watcrs, 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. Naviga- 

 tors have often been struck with the great and sudden changes in 

 the temperature of the water hereabouts. In the course of a sin- 

 gle day's sail in this part of the ocean, changes of 15°, or 20°, and 

 even of 80°, have been observed to take place in the temperature 

 of the sea. The cause has puzzled navigators long, but how ob- 

 vious is it now made to appear ! This " bend" is the great recep- 

 tacle of the icebergs which drift down from the north ; covering 

 frequently an area of hundreds of miles in extent, its waters differ 

 as much as 20°, 25°, and in rare cases even as much as 80° of tem- 

 perature from those about it. Its shape and place are variable. 

 Sometimes it is like a peninsula, 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 of 50°. 



782. By its discovery we have clearly unmasked the very seat 

 The fogs of Newfound- of that agcut which produces the Newfoundland 

 ^''^^' fogs. It is spread out over an area frequently em- 

 bracing several thousand square miles in extent, covered with 

 cold water, and surrounded on three sides, at least, with an im- 

 mense body of warm. May it not be that the proximity to each 

 other of these two very unequally heated surfaces out upon the 

 ocean would be attended by atmospherical phenomena not unlike 

 those of the land and sea breezes ? These warm currents of the 

 sea are powerful meteorological agents. I have been enabled to 

 trace in thunder and lightning the influence of the Gulf Stream 

 in the eastern half of the Atlantic as far up as the parallel of 6o° 

 N., for there, in the dead of winter, a thunder-storm is not unusual. 



783. These isothermal lines of 50°, 60°, 70°, 80°, etc., may 

 Aqueous isothermal iH^istratc for US the manner in which the climates 

 ^^^ in the ocean are reorulated. Like the sun in the 



