CUBA, the largest as well as the most important of the islands in the West Indian seas, is situated to the south of Florida, between the northernmost point of Yucatan, and the westernmost point of the island of Hayti, or Hispaniola. The western part of Cuba, nearly shuts in with the northern shore of Yucatan and the western coast of East Florida, that immense basin known by the name of the gulf of Mexico; it is strongly suspected that Cape Catoche in Yucatan and the most western headland of Cuba, were formerly united by an isthmus, which has been gradually worn away by the pressure and action of the waters of the Caribbean sea. Should this have actually been the case, the Mexican gulf must have been very shallow, as we find that the passage of the waters of the South Atlantic, impelled by the trade-winds through the strait formed by Cuba and Yucatan, is, although it has considerable breadth, so very forcible, as to send a vast stream or current, with great impetuosity round the gulf and through the straits of Florida, as far as the banks of Newfoundland, and to the northern shores of Europe. This stream is distinguishable in the North Atlantic, by its superior heat to the rest of the waters of that ocean, and by a body of sea-weed which constantly accompanies it. This the author has observed considerably to the east of the great bank of Newfoundland, as well as small land birds, which he cannot imagine could have reached those latitudes by the aid of flight alone. Might they not have been conveyed on the masses of sea-weed (which also envelope wreck and trunks of trees) borne by this upper current from the Mexican gulf? The extent of Cuba is from 73° 50ʹ, to 85° 30ʹ of west longitude from east to west; its form is so curved, that it lies, although narrow, between 23° 20ʹ, and 19° 40ʹ north latitude; it is about 700 miles long, but not more than seventy in medial breadth. Its position gives it the command of the gulf of Mexico, by the Straits of Yucatan and Florida, as well as the navigation of the windward passage and channel of Bahamas. The fine harbour of the Havannah, and some other smaller ports, renders this island, with the before-mentioned advantages, the most important of the West India islands, particularly to Spain, possessing as she does the shores of the Mexican gulf. The Spanish Government, have accordingly spared no expence in fortifying the Havannah, on which they seem to place their chief dependence for the security of their ultramarine colonies.