680 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



winds, or by being forced against the opposing shores of the ocean 

 basins. It never seems to have occurred to any author or naviga- 

 tor that the normal path of a great ocean current is necessarily 

 elliptical, and that it would pursue this path if no shores or winds 

 existed to deflect it from its true course. 



According to the commonly received theory, a current which 

 moves alternately to and from the equator and the north polar 

 region, must flow northeast from the equator all the way to its 

 northern terminus, as a surface current, and then return as a deep 

 under current, running southwest. The only ellipse formed would 

 be a vertical one ; the warm current flowing above and the cold 

 current returning immediately below it to the equator. This 

 theory is contradicted in every ocean by more than half of the 

 actual currents, ajid consequently its adherents are repeatedly 

 forced to resort to adverse winds and deflecting shores to account 

 for the numerous discrepancies which they encounter. 



Let us take the current that circulates around the North Atlantic 

 ocean as an example, by means of which to explain our theory, and 

 the principles involved in all the analogous cases of elliptical 

 currents. 



When a current runs in a circle or ellipse, it cannot be properly 

 said to have a beginning or an end; but, for convenience of descrip- 

 tion, let us say that this current commences in or near the Gulf of 

 Mexico, at the 25th degree of north latitude, and flows north-east 

 to the banks of Newfoundland, in the 45th degree of north lati- 

 tude; it then turns and flows nearly due east, almost or quite to 

 the shores of Europe, then south-east to the African coast, then 

 south-west to near the equator, thence due west to South America, 

 and then north-west to the Gulf of Mexico, from whence it started. 



When the water leaves the Gulf of Mexico — the 25th degree — 

 it doubtless possesses the easterly velocity proper to the earth in 

 that latitude. At all events let us, for the sake of illustration, 

 assume that it does so. Of course, according to the principles 

 already explained, it must move north-east. When it has pro- 

 ceeded five deirrees of latitude, and has arrived at the 30th degree, 

 it has brought with it a greater amount of easterly velocity than 

 the earth in the 30th degree possesses. The water of the current 

 differs from the proper water of the 30th degree. Let us repre- 

 sent the difference by the number five. This surplus, or diflerence, 

 the current retains, and proceeds on its way north-east. When it 

 arrives at the 35th degree of north latitude, the difference has 



