I Wished To Compare In The Morning The Altitudes Taken With An Artificial Horizon And Those Taken With The Horizon Of The Sea; To Verify The Apparent Depression Of The Latter, By The Barometrical Measurement Of The Hill.

By this method, hitherto very little employed, on reducing the heights of the sun to the same time, a reflecting instrument may be used like an instrument furnished with a level.

I found the latitude of the cape to be 10 degrees 36 minutes 45 seconds; I could only make use of the angles which gave the image of the sun reflected on a plane glass; the horizon of the sea was very misty, and the windings of the coast prevented me from taking the height of the sun on that horizon.

The environs of Cabo Blanco are not uninteresting for the study of rocks. The gneiss here passes into the state of mica-slate (Glimmerschiefer.), and contains, along the sea-coast, layers of schistose chlorite. (Chloritschiefer.) In this latter I found garnets and magnetical sand. On the road to Catia we see the chloritic schist passing into hornblende schist. (Hornblendschiefer.) All these formations are found together in the primitive mountains of the old world, especially in the north of Europe. The sea at the foot of Cabo Blanco throws up on the beach rolled fragments of a rock, which is a granular mixture of hornblende and lamellar feldspar. It is what is rather vaguely called PRIMITIVE GRUNSTEIN. In it we can recognize traces of quartz and pyrites. Submarine rocks probably exist near the coast, which furnish these very hard masses. I have compared them in my journal to the PATERLESTEIN of Fichtelberg, in Franconia, which is also a diabase, but so fusible, that glass buttons are made of it, which are employed in the slave-trade on the coast of Guinea. I believed at first, according to the analogy of the phenomena furnished by the mountains of Franconia, that the presence of these hornblende masses with crystals of common (uncompact) feldspar indicated the proximity of transition rocks; but in the high valley of Caracas, near Antimano, balls of the same diabase fill a vein crossing the mica-slate. On the western declivity of the hill of Cabo Blanco, the gneiss is covered with a formation of sandstone, or conglomerate, extremely recent. This sandstone combines angular fragments of gneiss, quartz, and chlorite, magnetical sand, madrepores, and petrified bivalve shells. Is this formation of the same date as that of Punta Araya and Cumana?

Scarcely any part of the coast has so burning a climate as the environs of Cabo Blanco. We suffered much from the heat, augmented by the reverberation of a barren and dusty soil; but without feeling any bad consequences from the effects of insolation. The powerful action of the sun on the cerebral functions is extremely dreaded at La Guayra, especially at the period when the yellow fever begins to be felt. Being one day on the terrace of the house, observing at noon the difference of the thermometer in the sun and in the shade, a man approached me holding in his hand a potion, which he conjured me to swallow.

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