We had been warned that we would find the insects at Esmeralda even more cruel and voracious' than in this branch of the Orinoco; despite this we looked forward to sleeping in an inhabited place, and botanizing a little at last. At our last camp on the Casiquiare we had quite a fright. I presume to describe something that might not greatly interest a reader, but should be part of a journal of incidents on a river in such wild country. We slept on the edge of the jungle. At midnight the Indians warned us that they had heard a jaguar growl very close to us; it seemed to be up a nearby tree. The jungle is so thick here that only animals who climb trees exist. As our fires gave off 'plenty of light, and as we had become hardened to fear, we did not worry too much about the jaguar's cries. The smell and barking of one of our dogs had attracted the jaguar. This dog, a large mastiff, had barked at the Start, but when the jaguar approached the dog howled and hid under our hammocks. Since the Apure we had been used to this alternating bravery and fear in a young, tame and affectionate dog. We had a terrible shock the next morning. When getting ready to leave, the Indians told us that our dog had disappeared'. There was no doubt that the jaguar had killed it. Perhaps when it no longer heard the roars it had wandered off along the shore, or perhaps we slept so deeply we never heard the dog's yelps. We were often told that on the Orinoco and the Magdalena old jaguars were so clever that they hunted their prey in the very camps, and twisted their victims' necks so that they could not shout. We waited a long while in case the dog was merely lost. Three days later we returned to the same place and again heard a jaguar roar. So the dog, which had been our companion from Caracas, and had often swum away from crocodiles, had ended up being devoured in the jungle.

We could have included all these details in a work devoted solely to volcanoes in Peru and New Spain. Had I written the physical description of a single province I could have incorporated separate chapters on geography, mineralogy and botany, but how could I break the narrative of our travels, or an essay on customs and the great phenomena of general physics, by tiresomely enumerating the produce of the land, or describing new species and making dry astronomical observations? Had I decided to write a book that included in the same chapter everything observed from the same spot, it would have been excessively long, quite lacking in the clarity that comes from a methodical distribution of subject matter. Despite the efforts made to avoid these errors in this narration of my journey, I am aware that I have not always succeeded in separating the observations of detail from the general results that interest all educated minds. These results should bring together the influence of climate on organized beings, the look of the landscape, the variety of soils and plants, the mountains and rivers that separate tribes as much as plants. I do not regret lingering on these interesting objects for modern civilization can be characterized by how it broadens our ideas, making us perceive the connections between the physical and the intellectual worlds. It is likely that my travel journal will interest many more readers than my purely scientific researches into the population, commerce and mines in New Spain.

April 10th. We were unable to set sail until ten in the morning. It was hard to adapt to the new pirogue, which we saw as a new prison. To make it wider at the back of the boat we made branches into a kind of trellis, which stuck out on both sides. Unfortunately the leaf roof of this lattice-work was so low that you either had to lie down, and consequently saw nothing, or you had to stay hunched over. The need to transport pirogues across rapids, and even from one river to another, and the fear of giving too much hold to the wind by raising the toldo made this construction necessary for the little boats going up the Río Negro. The roof was designed for four people stretched Out on the deck or lattice-work, but your legs stuck far out, and when it rained half your body got wet. Worse still, you lie on oxhides or tiger skins, and the branches under the skins hurt you when you lie down. The front of the boat was filled with the Indian rowers, armed with 3-foot-long paddles in the form of spoons. They are all naked, sitting in twos, and row beautifully together. Their songs are sad and monotonous. The little cages with our birds and monkeys, increasing as we went on, were tied to the toldo and the prow. It was our travelling zoo. Despite losses due to accidents and sunstroke, we counted fourteen little animals when we came back from the Casiquiare. Every night when we established camp, our zoo and instruments occupied the middle; around them we hung our hammocks, then the Indians' hammocks and, outside, the fires we thought indispensable to scare off jaguars. At sunrise our caged monkeys answered the cries of the jungle monkeys.

The weather was cloudy, threatening one of those cloudbursts during which some 1 to 1. inches of rain may fall in a day. The sun shone on the tree-tops and, although we were not exposed to the rays, the heat was asphyxiating. Thunder rolled at a distance. The clouds hovered over the peaks of the high Guàcharo chain, and the plaintive howling of the araguatoes, heard so often in Caripe at sunset, announced the imminent storm. For the first time we had an opportunity to see those howler monkeys that belong to the family Alouatta (Stentor, Geoffroy), whose different species have long been confused by zoologists close at hand. While the small American sapajous, who imitate sparrow song with a whistle, have a simple, thin tongue bone, the large monkeys, the alouates and spider monkeys (Ateles, Geoffroy), have a tongue that rests on a large bony drum. The sad howling typical of the araguato is produced by air penetrating violently into this drum. I sketched these organs (59) on the spot as they are not well known to European anatomists. If you think about the size of the alouatta's bony box and the number of howler monkeys that can gather in one tree in the Cumanà and Guianan jungles, you will be less surprised by the force and volume of their united voices.