The external edges of La Caldera are almost perpendicular, rather like the Somma seen from the Atrio del Cavallo. We got to the bottom of the crater following a trail of broken lava from the eastern breach of the wall. We only felt the heat above the crevices, which exhaled watery vapors with a strange buzzing sound. Some of these crevices can be found on the outside of the crater, on the external parapet that surrounds it. A thermometer placed inside one of them rose suddenly from 68°C to 75°C. This would have risen higher, but we had to pull the thermometer out to prevent our hands from being burned It might be thought that these vapors, which escape in puffs of air, contain muriatic or sulphuric acids, but when condensed they had no particular taste. Experiments showed that these chimneys exhale pure water only.

The harbors of Ferrol and La Coruña both communicate with the samebay, so a ship driven by foul weather towards the coast may anchor ineither, according to the wind. Such an advantage is invaluable where thesea is almost always rough, as it is between Capes Ortegal and Finisterre, the promontories Trileucum and Artabrumof ancient geography. A narrow passage, flanked by perpendicular graniterocks, leads to the extensive bay of Ferrol. No port in Europe offers suchan extraordinary anchorage, from its very inland position. The narrow and tortuous passage by which vesselsenter this port has been opened, either by the pounding of waves or thereiterated shocks of very violent earthquakes. In the New World, on thecoasts of New Andalusia, the Lagunadel Obispo is formed exactly like the port of Ferrol. The most curiousgeological phenomena are often repeated at immense distances on the surfaceof different continents; and naturalists who have examined different partsof the globe are struck by the extreme resemblances observed in the fracturing of coasts, in the sinuositiesof the valleys, in the appearance of mountains, and in their distributionby groups. The accidental concurrence of the same causes must everywherehave produced the same effects; and amidst the variety of nature an analogy of structure and form is observedin the arrangement of inanimate matter, as well as in the internalorganization of plants and animals.