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 degrees 16 minutes 35 seconds; 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 degrees 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 degrees 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 degrees 51 minutes 44 seconds and the longitude of the eastern cape 68 degrees 26 minutes 5 seconds (supposing Nueva Barcelona to be 67 degrees 4 minutes 48 seconds). 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 degrees 19 minutes 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 degrees, while the sea maintained a temperature of 25.6 degrees 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 degrees. 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.

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