TEMPERATURE OF THE HYDROSPHERE 195 



for the oceans {2T,) and from his maps the following general facts 

 may be taken: For tropical waters, the range is small (less than 

 10° F. or 5.55° C.) in the Pacific between the tropics of Cancer and 

 Capricorn, except off the west coast of South America, where the 

 range increases to 15° or even 20° F. (11.11° C). In the Atlantic 

 this small range of less than 10° F. occupies about the same position, 

 except off the North African coast and the Gulf of Guinea. A sim- 

 ilar low range occurs in the Indian and Australian waters between 

 20° N. and S. lat., except in the Madagascar region, where a greater 

 range exists. Similar small ranges, but for low temperatures, exist 

 in the Arctic Ocean, except where the Gulf Stream carries warmth 

 to Iceland, and in the southern parts of the other oceans below 50° 

 or 60" S. lat. Ranges of 20° or over exist in the North Pacific 

 north of 40° N. lat. and in the North Atlantic between 30° and 55° 

 N. lat., likewise in the South Atlantic and Indian between 30° and 

 50° S. lat., from South America to New Zealand. The greatest 

 ranges of temperature, more than 50° F., or 27.78° C, are found in 

 the west Atlantic, eastward from the New England coast, and in 

 the western part of the Philippine Sea. Ranges from 30° to 40° F. 

 (16.66° to 22.22° C.) are found off the Rio de la Plata, and in the 

 Roman Mediterranean, the Black, Caspian, and Baltic seas and in 

 part of the North Sea, and in the northern ends of the Red Sea and 

 Arabian Gulf, as well as the western North Atlantic and the western 

 or Asiatic Pacific. 



Shifting of the areas of great range of temperature may be 

 brought about by storms or by change in currents or otherwise, and 

 such a shifting may be lateral or vertical. This results generally in 

 the wholesale destruction of animal life adapted to a smaller range, 

 as illustrated by the enormous destruction of Tile fish off the New 

 England coast in 1882, which exceeded in estimation the number of 

 one billion, and covered the floor of the ocean in this region to a 

 depth estimated at six feet with the bodies of dead Tile fish. The 

 influence of the changes in temperature on the destruction of life 

 will be more fully discussed in a subsequent chapter. 



Temperatures of the Terrestrial Waters. 



Temperatures of Lakes, Etc. Since lakes are mostly shallow 

 the seasonal variations in temperature are more pronounced through- 

 out than in the oceans or mediterraneans. The chief source of heat 

 is the sun, whose rays are absorbed to a greater or less extent. Re- 

 flection from the surface, however, greatly reduces the amount 



