PAPER BY PROF. OBERBECK. 187 



On the ocean where this system of winds can freely develop in the 

 manner here assumed, without the influence of continents, their course 

 is in good agreement with the conclusions of theory. Thus, on the 

 northern hemisphere, between 0° and 35° latitude, east and northeast 

 winds prevail ; at 35° nearly north or in general only feeble winds ; 

 in higher latitudes northwest and west winds. 



It results from the preceding that the two currents (la) and (16) are 

 of the same order of magnitude and give moderate winds in the lower 

 strata of atmosphere. Since now the current (26), in comparison with 

 (2a) is of a different order of magnitude, therefore the former is by far 

 the most intense of all currents of air, but only in the upper strata of 

 the atmosphere. 



In so far as this component combines with the upper current (la), it 

 forms in the tropics the southwest or upper trade wind. In higher 

 latitudes the purely westerly current prevails. So far as is known to 

 me, the observations of the highest clouds which show prevailing west 

 winds agree herewith. That the just-mentioned rotation-currents attain 

 a great velocity has its reason in this that they can circulate around 

 the whole earth without being hindered by the friction of a lower oppo- 

 site current, as for instance is the case with the meridional currents. 

 I consider it probable (as also W. Siemens has already announced) that 

 in this powerful upper current we have to seek for the principal source 

 of the energy found in the wind system of the lower strata. 



