Navigation.
Scraps from the Lucky Bay, by Harry Bluff.
Rebuilding Southern Commerce.
Wind and Current Charts.
Sailing Directions.
Physical Geography of the Sea.
Series of Geographies.
Physical Survey of Virginia.
Resources of West Virginia (with Wm. M. Fontaine).
Lanes for Steamers Crossing the Atlantic.
Amazon and Atlantic Slopes.
Magnetism and the Circulation of the Atmosphere.
THE GULF STREAM.
(From Sailing Directions.)
It is not necessary to associate with oceanic currents the idea that they must of necessity, as on land, run from a higher to a lower level. So far from this being the case, some currents of the sea actually run up-hill, while others run on a level. The Gulf Stream is of the first class. In a paper read before the National Institute in 1844, I showed why the bottom of the Gulf Stream ought, theoretically, to be an inclined plane, running upwards. If the Gulf Stream be 200 fathoms deep in the Florida Pass, and but 100 fathoms off Hatteras, it is evident that the bottom would be lifted 100 fathoms within that distance; and therefore, while the bottom of the Gulf Stream runs up-hill, the top preserves the water-level, or nearly so; for its banks are of sea-water, and being in the ocean, are themselves on a water-level. . .
. . . . . . .
I have also, on a former occasion, pointed out the fact, that, inasmuch as the Gulf Stream is a bed of warm water, lying between banks of cold water—that as warm water is lighter than cold—therefore, the surface of the Gulf Stream ought, theoretically, to be in the shape of a double inclined plane, like the roof a house, down which we may expect to find a shallow surface or roof current, running from the middle towards either edge of the stream.
The fact that this roof-current does exist has been fully established . . . . . . by officers of the navy. Thus, in lowering a boat to try a current, they found that the boat would invariably be drifted towards one side or other of the stream, while the vessel herself was drifted along in the direction of it. . .
This feature of the Gulf Stream throws a gleam of light upon the locus of the Gulf weed, by proving that its place of growth cannot be on this side (west) of that stream. No Gulf weed is ever found west of the axis of the Gulf Stream; and, if we admit the top of the stream to be higher in the middle than at the edges, it would be difficult to imagine how the Gulf weed should cross it, or get from one side of it to the other.
The inference, therefore, would be, that as all the Gulf weed which is seen about this stream is on its eastern declivity, the locus of the weed must be somewhere within or near the borders of the stream, and to the east of the middle. And this idea is strengthened by the report of Captain Scott, a most intelligent ship-master, who informs me that he has seen the Gulf weed growing on the Bahama Banks.