At the confluence of the Cameji and Orinoco we unloaded our baggage, and the Indians, familiar with all the shoals in the raudal, led the empty pirogue to the mouth of the Toparo river where the water is no longer dangerous. Each rock forming the falls of the raudal has a different name. As long as they are not more than 1. to 2 feet above water the Indians do not mind letting the current take their canoes; but to go up river they swim ahead and after much struggling tie cables to rocks and pull the boats up.

When we first glance at geographical maps, and read the narratives of navigators, we feel a special charm for certain countries and climates, which we cannot explain when older. These impressions exercise a considerable hold over what we do in life, and we instinctively try to connect ourselves with anything associated with these places. When I first studied the stars to identify them I was disturbed by a fear unknown to those who love sedentary life. It was painful to me to have to renounce the hope of seeing the beautiful constellations near the South Pole. Impatient to explore the equatorial regions I could not raise my eyes to the sky without dreaming of the Southern Cross and remembering a passage from Dante. Our joy over discovering the Southern Cross was vividly shared by those sailors who had lived in the colonies. In the solitudes of the oceans you wave at a star as if it is a friend you haven't seen for ages. Portuguese and Spaniards are particularly susceptible to this feeling; religious sentiments attach them to a constellation whose shape recalls the sign of the faith planted by their ancestors in the deserts of the New World.

We were received with eagerness by the monks of the hospice. The father superior was away but, notified of our departure from Cumanà, be had taken great pains to ensure our comfort at the convent. There was an inner cloister, typical of all Spanish monasteries. We used this enclosed space to install our instruments and get them working. In the convent we discovered a varied company; young monks recently arrived from Spain before being sent out to different missions, while old, sick missionaries recuperated in the healthy air of the Caripe bills. I was lodged in the father superior's cell, which had a notable library. To my surprise I found Feijòo's Teatro crítico, the Lettres édifiantes, and L'abbé Nollet's Traité d'électricité. Science has progressed to even the American jungles. The youngest of the Capuchin monks had brought with him a Spanish translation of Chaptal's treatise on chemistry, (56) which he intended to study in the isolation of the mission where he was to be abandoned on his own for the rest of his days. I doubt that the desire to learn can be kept alive in a young monk isolated on the banks of the Tigre river; but what is certain, and an honour to the spirit of this century, is that during our long stay in South American missions we never saw the least sign of intolerance.

We had yet to climb the steepest part of the mountain, the Piton, which forms the summit. The slope of this small cone, covered with volcanic ashes and fragments of pumice-stone, is so steep that it would have been impossible to reach the top had we not been able to follow an old lava current that seemed to have flowed down from the crater and whose remains have defied the ravages of time. The debris forms a wall of scoria, which reaches into the loose ash. We climbed to the Piton by clinging to this sharp-edged scoria, which, worn down by the weather, often broke off in our hands. It took us half an hour to reach the top, though it was only some 90 toises above us.

The decision we took on the night of the 14th of July had a happy influence on the direction of our travels. Instead of weeks, we spent year in this part of the world. Had not the fever broken out on board the Pizarro we would never have explored the Orinoco, the Casiquiare and the frontiers with the Portuguese possessions on the Rio Negro. We perhaps also owed to this circumstance the good health we enjoyed for such a long period in the equinoctial regions.

Connected by the most intimate bonds of friendship over the five years of our travels (and since then), Bonpland and I have jointly published the whole of our work. I have tried to explain what we both observed but, as this work has been written from my notes on the spot, all errors that might arise are solely mine. In this introduction I would also like to thank Gay-Lussac and Arago, my colleagues at the Institute, who have added their names to important work done, and who possess that high-mindedness which all who share a passion for science should have. Living in intimate friendship I have consulted them daily on matters of chemistry, natural history and mathematics.