In order to the laying down my Sentiment on the Florida Current, I shall premise the Facts and Observations of our Pilots in relation to this Gulph, and that of Mexico, which have a Dependency as to the Cause of it, with each other.
1. This Stream goes constantly out to the Northward in mid Channel, its Force having some respect (like Tides in other Channels) to the Moon and to the Winds; with a counter Current, or at least a Stillness of the Water in shore, that will enable a Ship to turn through, be the middle Stream never so strong; the same as in the Strait of Gibraltar, where tho’ the Current is continually into the Mediterranean, Ships may work through, keeping the Shore aboard.
2. The Current which goes out here, sets for the most part into the Gulph of Mexico, between the two Capes of Corientes and Catoche, with counter Currents in shore; tho’ not always so, the Pilots having observed them strong to the East, new, and full Moons.
3. As to the Bay of Mexico it self, there are every where Currents round it various and uncertain, as to the Point they run on, or time of Continuance, especially on the Apalachian Side where it is safest stopping in the Night, and up Anchor only, in the Day. That these Currents are less discernible the farther from shore, and for the most part, bend to the Trend of the Lands; that is, when you have rounded Cape Catoche, it sets Westward, open with Campechy Bay to the Southward: From Vera Cruz in 19°° to the Latitude of 28°° it runs to the Northward, and thence round the Bay to the Eastward; more perceptible, I say, the nearer shore, because bounded, and makes the Tides in the Rivers.
4. The Rivers of Georgia, and Carolina (next Coast to Florida Northward) have as regular Tides as the Thames. So again, in the Bay of Honduras Southward, whose Reflux, it must be taken notice, makes a Northern Current.
Now to sum up all, in order to account for the Current of Florida, which seems to me only this, that more of the Flood is propagated into the Bay of Mexico, by that Passage made from the West End of Cuba, and Shore of Yucatan; and more of the Ebb by the Chanel of Florida, and for these Reasons.
The Gulph of Mexico receives many and large Rivers, whose Mouths together carry some proportion with the Chanel of Florida; and consider’d as a little Mediterranean Sea, the Flood in it must have a more remarkable and strong Ebb: which shews it self rather here, first, because the Make of the Lands gives a freer Opening and Tendency of the Waters that way. Second, The Length and Contraction of the Channel, makes it more visible and constant, and is the Continuance of those River-Streams (that disembogue in the Bay) even till it meets with the Tide to the Northward, which checks, like as at them, and produces a counter Current along shore: for we may observe, that altho’ the Current goes constantly out in the Channel, yet at the Isle of Providence contiguous to it almost, the Tides are alternate and regular. Third, The Winds at East are more favourable to the Exit than the Trade, which sets in directly at the other Passage, and while it helps the Flood there, is at the same time an Obstacle to its Return; to which assists also that Northern Current from the Bay of Honduras; nor will it be so perceptible there, because what Reflux is, opens to a wider Sea immediately, and probably had been the same at Florida, if the Gulph of Mexico had open’d without such Restraint to the main Ocean directly.
On this Supposition, the Variety and Uncertainty of Currents in the Bay, and the greater or less Rapidity in the Chanel, will depend much on the Winds without; and as they are dry or wet Seasons at Land, new and full Moons should influence the Strength of the Stream; and hard Gales concurring at N. or N E. among the Bahamas, should slacken it there, and promote an Eastern Current at the other Passage.
