174 Baron N. Schilling on the Constant Currents 



which flows in a narrow band along the equator and is named, 

 in Berghaus's ' Chart of the World/ the " equatorial counter- 

 current." In the air this current does not exist. It would 

 therefore have to be ascertained if this equatorial counter-current 

 is a constant one or is only to be observed when the moon ap- 

 proaches the tropics, and whether it is not wanting when the sun 

 and moon are simultaneously in the vicinity of the equator. 



The shifting of the trade-wind zones appears to be on the 

 whole more considerable than that of the sea-currents, and seems 

 in many cases to coincide with the change of the seasons of the 

 year — which, then, proves that the sun by its heat also exercises 

 an influence on the trade-winds. This probably takes place 

 chiefly through the sun's action on the aqueous vapour in the 

 atmosphere and through other collateral circumstances. The 

 main cause, however, of the production of the trade-winds must 

 certainly be ascribed to the attraction of the moon and sun ; 

 and hence their position relatively to each other must have a 

 sensible influence upon various atmospheric phenomena. It 

 appears, therefore, possible that the well-known old popular tra- 

 dition of the phases of the moon affecting the change of the 

 weather may have some foundation ; only it might be more cor- 

 rect to ascribe this influence not to the phases, but to the dis- 

 tance and declination of the moon, which latter, it is true, stands 

 in a certain connexion with the moon's phases and the sun's 

 declination. At the times, namely, of new and full moon the 

 difference between the declination of the moon and that of the 

 sun is always inconsiderable, although at the time of full moon 

 the sun and moon are in different hemispheres but at nearly 

 equal distance from the equator. 



Only at the time of the quadratures can the difference of de- 

 clination of the sun and moon be considerable ; at the periods of 

 the equinoxes and the solstices the difference rises at the utmost 

 to near 28°. 



From the production of currents by the moon's attraction not 

 only can the sea-currents parallel to the equator, but also the 

 meridional currents be naturally derived. 



If the whole earth were covered with water, the equatorial 

 current would flow round it unhindered ; but now the continents 

 stand as insuperable obstacles in the way of this motion. As, 

 however, the cause of the flow is not hereby removed, the cur- 

 rent in the ocean must continue and cannot suddenly cease on 

 impinging against the coast, but must change its direction ac- 

 cording to the position of the shore. Thus we see, in the 

 Atlantic Ocean, that the southern equatorial stream divides at 

 Cape St. Roque (which opposes it like a wedge), and, following 

 the direction of the coast, is turned aside, part to the north-west 



