2U THE ATMOSPHEEE AND METEOEOLOGT. 



whicli the atmospheric currents bring. The Sahara, and in a less 

 degree all the tropical countries of the northern hemisphere, act as 

 a great centre, towards which the aerial masses flow. It results 

 from the tables drawn up by Dove, that the mean temperature of 

 the j^ear is more elevated (92° Fahr.) towards the 10th degree north 

 latitude, than it is at the equator itself (91v5° Fahr), while the mean 

 balance is stronger towards the 20th degree of latitude (94'' Fahr.) 

 than in any other region of the world.* The high temperature of the 

 continents thus forces the southern s^^stem of winds to encroach upon 

 the northern system. 



* Dove, Vorhereitung der Wdrme atif der Oberjluche der Erde. 



