The hypothesis that during the Cumana earthquakes elastic fluids escape from the earth's surface seems confirmed by the dreadful noise heard during the shocks near the wells in the plain of Charas. Water and sand are sometimes thrown 20 feet high. Similar phenomena did not escape the ancients' notice in areas of Greece and Asia Minor, in caves, crevices and underground rivers. Nature, in its uniform progress, everywhere gives birth to the same ideas concerning the causes of earthquakes, and man, forgetting the measure of its force, tries to diminish the effect of underground explosions. What the great Roman naturalist Pliny said about how wells and caves are the cause is repeated by the most ignorant Indians of Quito when they show travelers the guaicos, or crevices, of Pichincha.

During our six-day stay at Cartagena, our most interesting excursions were to the Boca Grande and the Popa hill with its fine view. The port, or bahía, is 9. miles long. The unhealthiness of Cartagena comes from the great marshes surrounding the town on the east and north. The Ciénaga de Tesca is more than 15 miles long. A sad vegetation of cactus, Jatropha gossypifolia, croton and mimosa covers the arid slopes of Cerro de la Popa. While botanizing on these wild spots our guides pointed out a thick Acacia cornigera bush infamous for a deplorable event. This acacia is armed with very sharp thorns, and extraordinarily large ants live on it. A woman, annoyed by her husband's well-founded jealousy, planned a barbarous revenge. With the help of her lover she tied her husband up with rope, and at night chucked him into this Acacia cornigera bush. The more violently he struggled the more the sharp thorns tore his skin. His screams were heard by some passers-by who found him after several hours covered with blood and dreadfully stung by ants. This crime is without example in the history of human perversion; the violence of its passion derives from the coarseness of manners, not from the Tropics. My most important work at Cartagena was comparing my observations with the astronomical positions fixed by Fidalgo's officers.

Some of the rivers flowing into Lake Valencia come from thermal springs, worthy of special note. These springs gush out at three points from the coastal granitic chain at Onoto, Mariara and Las Trincheras. I was only able to carefully examine the physical and geological relations of the thermal waters of Mariara and Las Trincheras. All the springs contain small amounts of sulphuretted hydrogen gas. The stink of rotten eggs, typical of this gas, could only be smelled very close to the spring. In one of the puddles, which had a temperature of 56.2°C, bubbles burst up at regular intervals of two to three minutes. I was not able to ignite the gas, not even the small amounts in the bubbles as they burst on the warm surface of the water, nor after collecting it in a bottle, despite feeling nausea caused more by the heat than by the gas. The water, when cold, is tasteless and quite drinkable.

We saw the Indians dancing. These dances are all the more monotonous as women do not dare take part. The men, both young and old, hold hands, form a circle, and for hours turn around to the right, then the left, in utter silence. Usually the dancers themselves are the musicians. Weak notes blown from reeds of different sizes make it all seem slow and sad. To mark the time the leading dancer bends both knees rhythmically. The reeds are tied together in rows. We were surprised to see how quickly young Indians could cut reeds and tune them as flutes when they found them on the banks.