Note 24 — STEPPES AND DESERTS.

p. 12.—“Caused by the great revolving current.”

In the northern part of the Atlantic, between Europe, North Africa, and the New Continent, the waters of the ocean are driven round in a true revolving current, or circle. This general current,—which, from its cause, might be called a “Rotation Current,”—moves between the tropics, as is well known, with the trade wind, from east to west. It accelerates the passage of ships sailing from the Canaries to South America, and makes it almost impossible to sail “up stream,” or in a direct line from Cartagena de Indias to Cumana. This set to the west, attributed to the trade winds, receives, however, in the Caribbean Sea, the accession of a much stronger movement, originating in a very remote cause, which was discovered as early as 1560 by Sir Humphrey Gilbert, (Hakluyt, Voyages, vol. iii. p. 14), and developed with greater certainty by Rennell in 1832. The Mosambique current, flowing from north to south between Madagascar and the east coast of Africa, sets on the Lagullas Bank, turns on the north side of it round the south point of Africa, and advances with much force up the western coast of the Continent to a little beyond the equator near the Island of St. Thomas. It gives at the same time a north-westerly direction to a part of the water of the South Atlantic, causing it to strike Cape St. Augustin, and to follow the coast of Guiana to beyond the mouth of the Orinoco, the Boca del Drago, and the coast of Paria. (Rennell, Investigation of the Currents of the Atlantic Ocean, 1832, p. 96 and 136.) The New Continent, from the Isthmus of Panama to the northern part of Mexico, opposes a barrier to the farther continuance of this movement of the waters, and thus the current is constrained to assume a northerly course off Veragua, and thence to follow the windings of the coast of Costa Rica, Mosquito, Campeachy, and Tabasco. The waters which enter the Mexican Gulf between Cape Catoche of Yucatan and Cape San Antonio of Cuba, after completing a great rotatory movement or circuit, by Vera Cruz, Tamiagua, the mouth of the Rio Bravo del Norte, and that of the Mississipi, force their way northwards through the Bahama Channel, and re-issue into the open ocean. Here they form the well-known “Gulf Stream,” a current or river of warm and rapidly moving water, flowing in an oblique or diagonal direction carrying it farther and farther from the North American coast. Ships from Europe bound for this coast, when uncertain in respect to their longitude, are enabled by this oblique direction of the current to direct their course, as soon as they reach the Gulf Stream, by observations of latitude only. The position of this great current was first indicated with accuracy by Franklin, Williams, and Pownall.

From the 41st degree of latitude, the river of warm water, which has been gradually diminishing in rapidity and increasing in breadth, turns suddenly to the east. It almost touches the southern edge of the great Newfoundland bank, where I found the greatest amount of difference between the temperature of the warm water of the Gulf stream, and that of the waters resting on the banks and subjected thereby to a cooling process. Before the stream reaches the westernmost of the Azores it divides into two branches, one of which, at least at certain seasons, advances towards Ireland and Norway, and the other towards the Canaries and the West Coast of Africa. This Atlantic rotatory movement, (described by me in more detail in the first volume of my Voyage to the Equinoctial Regions), explains the possibility of trunks of South American and West Indian trees being carried, in spite of the trade winds, to the coasts of the Canary Islands, and stranded there. I have made many experiments on the temperature of the Gulf Stream in the vicinity of the Banks of Newfoundland. The Stream brings the warmer water of lower latitudes into more northern regions with much rapidity, and I have thus found its temperature two or three degrees of Reaumur (5° to 7° Fah.) higher than that of the adjacent unmoved masses of water, which form as it were the banks of the warm oceanic river.

The flying fish of the tropics (Exocetus volitans) accompanies the warm water of the Gulf Stream far into the temperate zone. Floating sea-weed (Fucus natans), chiefly taken up by the stream in the Gulf of Mexico, shews when a ship is entering the current, and the arrangement of the branches of the sea-weed shews the direction of the movement of the water. The mainmast of the English ship of war, the Tilbury, destroyed by fire on the coast of San Domingo, was carried by the Gulf Stream to the north coast of Scotland. Even casks filled with palm oil, the remains of the cargo of a ship wrecked off Cape Lopez on the coast of Africa, were carried in the same manner to Scotland[*], after having twice traversed the whole breadth of the Atlantic; once from east to west with the equatorial current between 2° and 12° N. lat., and once from west to east by the aid of the Gulf Stream, between 45° and 55° N. lat. Rennell, in p. 347 of the “Investigation of Currents,” relates the voyage of a bottle with papers enclosed, thrown overboard by the English ship Newcastle on the 20th of January, 1819, in lat. 38° 52′, and long. 63° 58′, which was picked up on the 2nd of June, 1820, at the Rosses, (near the Island of Arran), on the west coast of Ireland. A short time before my arrival at Teneriffe a stem of South American cedar (Cedrela odorata), well covered with lichens, had been cast ashore in the harbour of Santa Cruz.

Effects of the Gulf Stream in stranding on the Islands of Fayal, Flores, and Corvo in the Azores, bamboos, artificially cut pieces of wood, trunks of an unknown species of Pine from Mexico and the West Indian Islands, and corpses of men of unknown race with unusually broad faces, contributed to the discovery of America, by confirming Columbus in his belief of the existence to the westward of Asiatic countries and islands at no impassable distance. The great discoverer even heard from the lips of settlers near the Cape de la Verga in the Azores, of some, “who, in sailing westward, had met decked or covered boats, manned by persons of strange and foreign appearance, and built apparently in such a manner that they could not founder,—almadias con casa movediza que nunca se hunden.” There is highly credible and well-confirmed testimony to the fact, much as it has long been doubted, of natives of America, (probably Esquimaux from Greenland or Labrador), carried by currents or driven by storms from the North West, having actually crossed the Atlantic in their canoes and reached our shores. James Wallace, in his “Account of the Islands of Orkney, (1700, p. 60),” relates, that in 1682 a Greenlander was seen in his boat off the South Point of the Island of Eda by several persons, who did not succeed in bringing him to shore. In 1684, a Greenland fisherman appeared in his boat off the Island of Westram. In the church at Barra there was suspended an Esquimaux boat, driven thither by currents and tempests. The inhabitants of the Orkneys call Greenlanders so appearing among them Finns or “Finnmen.”

In Cardinal Bembo’s History of Venice, I find a narrative to the effect that in 1508 a French ship captured near the English coast a small boat, with seven persons of a strange and foreign appearance. The description suits extremely well with Esquimaux, (homines erant septem mediocri statura, colore subobscuro, lato et patente vultu, cicatriceque una violacea signato.) No one understood their language. Their clothing was composed of fish skins sewn together. On their heads they wore “coronam e culmo pictam, septem quasi auriculis intextam.” They ate raw flesh, and drank blood as we would wine. Six of the men died during the passage of the vessel, on board which they had been taken; but the seventh, a youth, was presented to the king of France, who was then at Orleans. (Bembo, Historia Venetæ, ed. 1718, lib. vii. p. 257).

The appearance of men called Indians on the western coasts of Germany, under the Othos, and under Frederic Barbarossa, in the 10th and 12th centuries, and even, as is related by Cornelius Nepos, (ed. Van Staveren, cur. Bardili, T. ii., 1820, p. 356), Pomponius Mela, (lib. iii. cap. 5, § 8), and Pliny, (Hist. Nat., T. ii. p. 67), when Quintus Metellus Celer was Pro-consul in Gaul, may be explained by similar effects of currents and north-west winds of long continuance. A king of the Boii, others say of the Suevi, gave the shipwrecked dark-coloured men to Metellus Celer. Gomara, in his Historia Gen. de las Indias, (Saragossa, 1553, fol. vii.), refers to this account, and considers the Indians spoken of in it to have been natives of Labrador. “Si ya no fuesen de Tierra del Labrador, y los tuviesen, los Romanos por Indianos engañados en el color.” The appearance of Esquimaux on the northern coasts of Europe may be believed to have occurred more often in earlier times, because we know, from the researches of Rask and Finn Magnusen, that in the 11th and 12th centuries this race extended in considerable numbers, under the name of the Skrälinges of Labrador, even as far south as the “good Vinland;” i. e., the coast of Massachusets and Connecticut. (Kosmos, Bd. ii. S. 270; English ed. p. 234; Examen critique de l’Hist. de la Géographie, T. ii. p. 247–278.)

As the winter cold of the most northern parts of Scandinavia is softened by the influence of the Gulf Stream, by which American tropical fruits (cocoa nuts, and seeds of the Mimosa scandens and the Anacardium occidentale) are cast upon the shore beyond the 62nd degree of latitude, so does Iceland also occasionally enjoy the beneficial influence of the extension of the warm waters of the Gulf Stream far to the northward. The coasts of Iceland as well as those of the Färoe Islands, receive a great deal of drift-wood, which, coming formerly in greater abundance, was cut into beams and planks and used for building timber. Fruits of tropical plants, collected on the coast of Iceland, between Raufarhavn and Vapnafiord, testify the movement of the waters from the southward. (Sartorius von Waltershausen, physisch-geographische Skizze von Island, 1847, S. 22–35.)