Travels to the Equinoctial Regions of America, by Alexander von Humboldt



We sailed from Nueva Barcelona on the 24th of November at nine o’clock in the evening; and we doubled the small rocky island of Borachita. The night was marked by coolness which characterizes the nights of the tropics, and the agreeable effect of which can only be conceived by comparing the nocturnal temperature, from 23 to 24° centigrade, with the mean temperature of the day, which in those latitudes is generally, even on the coast, from 28 to 29°. Next day, soon after the observation of noon, we reached the meridian of the island of Tortugas. It is destitute of vegetation; and like the little islands of Coche and Cabagua is remarkable for its small elevation above the level of the sea.

In the forenoon of the 26th we began to lose sight of the island of Marguerita and I endeavoured to verify the height of the rocky group of Macanao. It appeared under an angle of 0° 16′ 35″; which in a distance estimated at sixty miles would give the mica-slate group of Macanao the elevation of about 660 toises, a result which, in a zone where the terrestrial refractions are so unchanging, leads me to think that the island was less distant than we supposed. The dome of the Silla of Caracas, lying 62° to the south-west, long fixed our attention. At those times when the coast is not loaded with vapours the Silla must be visible at sea, without reckoning the effects of refraction, at thirty-three leagues distance. During the 26th, and the three following days, the sea was covered with a bluish film which, when examined by a compound microscope, appeared formed of an innumerable quantity of filaments. We frequently find these filaments in the Gulf-stream, and the Channel of Bahama, as well as near the coast of Buenos Ayres. Some naturalists are of opinion that they are vestiges of the eggs of mollusca: but they appear to be more like fragments of fuci. The phosphorescence of sea-water seems however to be augmented by their presence, especially between 28 and 30° of north latitude, which indicates an origin of some sort of animal nature.

On the 27th we slowly approached the island of Orchila. Like all the small islands in the vicinity of the fertile coast of the continent it has never been inhabited. I found the latitude of the northern cape 11° 51′ 44″ and the longitude of the eastern cape 68° 26′ 5″ (supposing Nueva Barcelona to be 67° 4′ 48″). Opposite the western cape there is a small rock against which the waves beat turbulently. Some angles taken with the sextant gave, for the length of the island from east to west, 8.4 miles (950 toises); and for the breadth scarcely three miles. The island of Orchila which, from its name, I figured to myself as a bare rock covered with lichens, was at that period beautifully verdant. The hills of gneiss were covered with grasses. It appears that the geological constitution of Orchila resembles, on a small scale, that of Marguerita. It consists of two groups of rocks joined by a neck of land; it is an isthmus covered with sand which seems to have issued from the floods by the successive lowering of the level of the sea. The rocks, like all those which are perpendicular and insulated in the middle of the sea, appear much more elevated than they really are, for they scarcely exceed from 80 to 90 toises. The Punta rasa stretches to the north-west and is lost, like a sandbank, below the waters. It is dangerous for navigators, and so is likewise the Mogote which, at the distance of two miles from the western cape, is surrounded by breakers. On a very near examination of these rocks we saw the strata of gneiss inclined towards the north-west and crossed by thick layers of quartz. The destruction of these layers has doubtless created the sands of the surrounding beach. Some clumps of trees shade the valleys, the summits of the hills are crowned with fan-leaved palm-trees; probably the palma de sombrero of the Llanos (Corypha tectorum). Rain is not abundant in these countries; but probably some springs might be found on the island of Orchila if sought for with the same care as in the mica-slate rocks of Punta Araya. When we recollect how many bare and rocky islands are inhabited and cultivated between the 17th and 26th degrees of latitude in the archipelago of the Lesser Antilles and Bahama islands, we are surprised to find those islands desert which are near to the coast of Cumana, Barcelona and Caracas. They would long have ceased to be so had they been under the dominion of any other government than that to which they belong. Nothing can engage men to circumscribe their industry within the narrow limits of a small island when a neighbouring continent offers them greater advantages.

We perceived at sunset the two points of the Roca de afuera, rising like towers in the midst of the ocean. A survey taken with the compass placed the most easterly of the points or roques at 0° 19′ west of the western cape of Orchila. The clouds continued long accumulated over that island and showed its position from afar. The influence of a small tract of land in condensing the vapours suspended at an elevation of 800 toises is a very extraordinary phenomenon, although familiar to all mariners. From this accumulation of clouds the position of the lowest island may be recognized at a great distance.

On the 29th November we still saw very distinctly, at sunrise, the summit of the Silla of Caracas just rising above the horizon of the sea. At noon everything denoted a change of weather in the direction of the north: the atmosphere suddenly cooled to 12.6°, while the sea maintained a temperature of 25.6° at its surface. At the moment of the observation of noon the oscillations of the horizon, crossed by streaks or black bands of very variable size, produced changes of refraction from 3 to 4°. The sea became rough in very calm weather and everything announced a stormy passage between Cayman Island and Cape St. Antonio. On the 30th the wind veered suddenly to north-north-east and the surge rose to a considerable height. Northward a darkish blue tint was observable on the sky, the rolling of our small vessel was violent and we perceived amidst the dashing of the waves two seas crossing each other, one the from north and the other from north-north-east. Waterspouts were formed at the distance of a mile and were carried rapidly from north-north-east to north-north-west. Whenever the waterspout drew near us we felt the wind grow sensibly cooler. Towards evening, owing to the carelessness of our American cook, our deck took fire; but fortunately it was soon extinguished. On the morning of the 1st of December the sea slowly calmed and the breeze became steady from north-east. On the 2nd of December we descried Cape Beata, in a spot where we had long observed the clouds gathered together. According to the observations of Acherner, which I obtained in the night, we were sixty-four miles distant. During the night there was a very curious optical phenomenon, which I shall not undertake to account for. At half-past midnight the wind blew feebly from the east; the thermometer rose to 23.2°, the whalebone hygrometer was at 57°. I had remained upon the deck to observe the culmination of some stars. The full-moon was high in the heavens. Suddenly, in the direction of the moon, 45° before its passage over the meridian, a great arch was formed tinged with the prismatic colours, though not of a bright hue. The arch appeared higher than the moon; this iris-band was near 2° broad, and its summit seemed to rise nearly from 80 to 85° above the horizon of the sea. The sky was singularly pure; there was no appearance of rain; and what struck me most was that this phenomenon, which perfectly resembled a lunar rainbow, was not in the direction opposite to the moon. The arch remained stationary, or at least appeared to do so, during eight or ten minutes; and at the moment when I tried if it were possible to see it by reflection in the mirror of the sextant, it began to move and descend, crossing successively the Moon and Jupiter. It was 12 hours 54 minutes (mean time) when the summit of the arch sank below the horizon. This movement of an arch, coloured like the rainbow, filled with astonishment the sailors who were on watch on the deck. They alleged, as they do on the appearance of every extraordinary meteor, that it denoted wind. M. Arago examined the sketch of this arch in my journal; and he is of opinion that the image of the moon reflected in the waters could not have given a halo of such great dimensions. The rapidity of the movement is no small obstacle in the way of explanation of a phenomenon well worthy of attention.

On the 3rd of December we felt some uneasiness on account of the proximity of a small vessel supposed to be a pirate but which, as it drew near, we recognized to be the Balandra del Frayle (the sloop of the Monk). I was at a loss to conceive what so strange a denomination meant. The bark belonged to a Franciscan missionary, a rich priest of am Indian village in the savannahs (Llanos) of Barcelona, who had for several years carried on a very lucrative contraband trade with the Danish islands. M. Bonpland and several passengers saw in the night at the distance of a quarter of a mile, with the wind, a small flame on the surface of the ocean; it ran in the direction of south-west and lighted up the atmosphere. No shock of earthquake was felt and there was no change in the direction of the waves. Was it a phosphoric gleam produced by a great accumulation of mollusca in a state of putrefaction; or did this flame issue from the depth of the sea, as is said to have been sometimes observable in latitudes agitated by volcanoes? The latter supposition appears to me devoid of all probability. The volcanic flame can only issue from the deep when the rocky bed of the ocean is already heaved up so that the flames and incandescent scoriae escape from the swelled and creviced part without traversing the waters.

At half-past ten in the morning of the 4th of December we were in the meridian of Cape Bacco (Punta Abacou) which I found in 76° 7′ 50″, or 9° 3′ 2″ west of Nueva Barcelona. Having attained the parallel of 17°, the fear of pirates made us prefer the direct passage across the bank of Vibora, better known by the name of the Pedro Shoals. This bank occupies more than two hundred and eighty square sea leagues and its configuration strikes the eye of the geologist by its resemblance to that of Jamaica, which is in its neighbourhood. It forms an island almost as large as Porto Rico.

From the 5th of December, the pilots believed they took successively the measurement at a distance of the island of Ranas (Morant Keys), Cape Portland and Pedro Keys. They may probably have been deceived in several of these distances, which were taken from the mast-head. I have elsewhere noted these measurements, not with the view of opposing them to those which have been made by able English navigators in these frequented latitudes, but merely to connect, in the same system of observations, the points I determined in the forests of the Orinoco and in the archipelago of the West Indies. The milky colour of the waters warned us that we were on the eastern part of the bank; the centigrade thermometer which at a distance from the bank and on the surface of the sea had for several days kept at 27 and 27.3° (the air being at 21.2°) sank suddenly to 25.7°. The weather was bad from the 4th to the 6th of December: it rained fast; thunder rolled at a distance, and the gusts of wind from the north-north-east became more and more violent. We were during some part of the night in a critical position; we heard before us the noise of the breakers over which we had to pass, and we could ascertain their direction by the phosphoric gleam reflected from the foam of the sea. The scene resembled the Raudal of Garzita and other rapids which we had seen in the bed of the Orinoco. We succeeded in changing our course and in less than a quarter of an hour were out of danger. While we traversed the bank of the Vibora from south-south-east to north-north-west I repeatedly tried to ascertain the temperature of the water on the surface of the sea. The cooling was less sensible on the middle of the bank than on its edge, a circumstance which we attributed to the currents that there mingle waters from different latitudes. On the south of Pedro Keys the surface of the sea, at twenty-five fathoms deep, was 26.4 and at fifteen fathoms deep 26.2°. The temperature of the sea on the east of the bank had been 26.8°. Some American pilots affirm that among the Bahama Islands they often know, when seated in the cabin, that they are passing over sand-banks; they allege that the lights are surrounded with small coloured halos and that the air exhaled from the lungs is visibly condensed. The latter circumstance appears very doubtful; below 30° of latitude the cooling produced by the waters of the bank is not sufficiently considerable to cause this phenomenon. During the time we passed on the bank of the Vibora the constitution of the air was quite different from what it had been when we quitted it. The rain was circumscribed by the limits of the bank of which we could distinguish the form from afar by the mass of vapour with which it was covered.

On the 9th of December, as we advanced towards the Cayman Islands,* the north-east wind again blew with violence. I nevertheless obtained some altitudes of the sun at the moment when we believed ourselves, though twelve miles distant, in the meridian of the centre of the Great Cayman, which is covered with cocoa-trees.

[* Christopher Columbus in 1503 named the Cayman Islands Penascales de las Tortugas on account of the sea-tortoises which he saw swimming in those latitudes.]

The weather continued bad and the sea extremely rough. The wind at length fell as we neared Cape St. Antonio. I found the northern extremity of the cape 87° 17′ 22″, or 2° 34′ 14″ eastward of the Morro of the Havannah: this is the longitude now marked on the best charts. We were at the distance of three miles from land but we were made aware of the proximity of the island of Cuba by a delicious aromatic odour. The sailors affirm that this odour is not perceived when they approach from Cape Catoche on the barren coast of Mexico. As the weather grew clearer the thermometer rose gradually in the shade to 27°: we advanced rapidly northward, carried on by a current from south-south-east, the temperature of which rose at the surface of the water to 26.7°; while out of the current it was 24.6°. We anchored in the port of the Havannah on the 19th December after a passage of twenty-five days in continuous bad weather.

Last updated Saturday, March 1, 2014 at 20:38