174 



HEAT OF THE WATERS. 



Degrees 



of 

 Latitude. 



Mean Temperature in Degrees. 



Northern Hemisphere. 



Southern Hemisphere. 



Cent. 



Fahr. 



Cent. 



Fahr. 





 10 

 20 

 30 

 40 

 50 

 60 

 70 

 80 



26 

 27-5 

 241 

 21-5 

 15 

 8-3 

 69 

 4-25 

 — 1-3 



78-8 



81-5 



75-4 



70 7 



59 



46-94 



44'4 



39-65 



3434 



26 

 27 

 24-1 

 22-2 

 155 

 92 



78-8 



80-6 



75-4 



71.96 



599 



48-56 



The temperature of the Pacific Ocean, is as vet 

 but little known. However, it has been shown 

 that it probably remains everywhere in the tem- 

 perate and polar zones, under the same latitudes, 

 about two or three degrees below that, of the At- 

 lantic Ocean. 



The oscillations about the mean temperature of 

 the year, that is to say the risings and fallings 

 above and below that point, are very small in the 

 open sea, and in temperate latitudes, where they 

 seem to be greatest scarcely amount to two or 

 three degrees (3°*6 C. or 5°'4 P.) 



The scope of the daily variations is naturally 

 still narrower at a distance from the coasts. The 

 air which plays over the sea cannot have a tempera- 

 ture differing very much from that of the surface of 

 the water ; and it is clear that this air, driven by the 

 wind to the coasts, must exert a powerful influence 



