in the Air and in the Sea. 101 



yet be perceptible everywhere. But this is by no means the 

 case. At the equator itself, or in its vicinity^ no such current 

 is to be observed either in the air or in the water; nay, in the 

 equatorial zone we find that the sea has a slight current flowing 

 east ; so that here, not only is no retardation to be traced, but 

 the water moves faster than the earth turns. In the zones of 

 the Sargasso-seas, again, and in the calms of the tropics, in both 

 hemispheres, neither in air nor sea can any diminution of the 

 rotation-velocity be perceived. Further polewards, especially 

 between the 40th and 50th parallels of latitude, the constant 

 west winds and currents flowing east testify that water and air 

 move eastwards more rapidly than the earth rotates. This cur- 

 rent in the atmosphere in the middle latitudes is explained by 

 the anti-trades, of which we have already spoken. It expresses 

 itself in the sea just as it does in the atmosphere ; but as the 

 anti-trade explanation is absolutely inapplicable to the water, 

 Miihry accounts for the sea-current by the aspirating force of 

 the equatorial stream. Why, however, this force has no action 

 at all upon the zones of the Sargasso-seas, but goes round them 

 in a wide arc, remains unexplained. Thus, for example, in the 

 South Atlantic the action of this aspirating force stretches along 

 the coast as far as the Cape of Good Hope, and thence across 

 the ocean to the American shore. If the aspirating force of the 

 Atlantic equatorial current were actually so great that its influ- 

 ence could make itself perceptible not only to the Cape of Good 

 Hope, but also from there to the American coast, then it could 

 not fail to lay hold of the Mozambique current at the Cape and 

 lead it into the Atlantic to supply the equatorial stream. Yet, 

 as is well known, at the Cape of Good Hope the Mozambique 

 current makes a strikingly sharp bend to the east, and returns 

 on a wide circuit to compensate the equatorial stream which 

 flows in the southern part of the Indian Ocean, after first wash- 

 ing the west coast of Australia. The insufficiency of the expla- 

 nation of currents by aspiration presents itself so distinctly that 

 it is scarcely necessary to dwell longer on the subject. 



The earth's rotation cannot, then, generate any currents in air 

 or sea ; it can only effect a slight tendency of the freely moving 

 air- and water-particles to shift their direction towards that of 

 the equator. This tendency, however, is so feeble that from it 

 no perceptible current can arise; hence we have not touched 

 this point in the Russian edition of this work. We will never- 

 theless more closely consider here the action of the centrifugal 

 force. 



Every rotating motion, and therefore also that of the earth 

 about its axis, generates a centrifugal force. The quantity of 

 this force for every single point of the earth's surface is readily 



