NATURAL PHILOSOPHY. 159 



Perceiving the importance of the results likely to be obtained, 

 the late Secretary of the Navy authorized these charts to be given to 

 every navigator, who would return to the National Observatory, ac- 

 cording to a form, an abstract of his voyages. Several thousand 

 sheets of the chart have already been distributed upon these terms; 

 and there are now engaged, in all parts of the Atlantic Ocean, hun- 

 dreds of vessels, making and recording observations. Thus it will 

 be seen, that in the course of two or three years the system will prob- 

 ably be nearly perfected, and to this time all intelligent navigators 

 look forward with much interest. 



Another result already obtained is, that, by examining the manner 

 in which the charts are cut up by the tracks of vessels, Lieut. Maury 

 is enabled to assert confidently, the non-existence of a number of 

 rigias, and other dangers of doubtful position, which disfigure our most 

 accurate charts. 



OCEANIC CURRENTS. 



WHILE Lieut. Maury is developing in this country a series of 

 charts, showing the actual winds and currents of the ocean, a French 

 saian, using like him, the results discovered by others, is endeavour- 

 ing to assign a cause for these currents. M. Babinet has communi- 

 cated to the French Academy an hypothesis with reference to the 

 universal law of currents, W 7 hich he supposes to hold good in the 

 main, though it will be found to be often modified by a great many 

 accidental circumstances. 



M. Babinet is not a seaman, but having carefully studied Dnper- 

 ry's " Chart of Oceanic Currents," and observed many other phenom- 

 ena of physical geography, he has built on them the following hy- 

 pothesis : The equatorial zone of the ocean is naturally much 

 broader than the others, therefore it expands and overflows itself to 

 both poles, while the water at the poles flows to the equator to re- 

 store the equilibrium; but owing to the revolution of the earth on 

 her axis, the velocity of the water strata, under the equator, is much 

 greater than that of those north and south of it, while the latter 

 have a lesser path to describe. It results from this, that the waters 

 which flow from the equator have an inclination to advance before 

 the motion of the earth, whilst those which come from the poles 

 have a tendency to remain behind the motion. If we cast a glance 

 over the formation of the several continents, the ocean will be found 

 divided into a certain number of basins, in which the force of this 

 law still endures; each basin has an eastern and western shore, and 

 is inclosed on the other side, by the equator and a boundary which 

 may reach to the pole. If the water which comes from the pole to 

 this point attains to the equatorial boundary, then it is behind the 

 motion of the earth, which goes from east to west; the counterpart 

 is found on the boundary opposite the pole, and to complete the 

 course, the water which flows from the pole runs along the western 

 boundary, and that which returns to the equator runs along the 

 eastern boundary. Let us cast a glance on the map of the earth, 



