Such considerations have guided my researches, and were always present in my mind as I prepared for the journey. When I began to read the many travel books, which form such an interesting branch of modern literature, I regretted that previous learned travelers seldom possessed a wide enough knowledge to avail themselves of what they saw. It seemed to me that what had been obtained had not kept up with the immense progress of several sciences in the late eighteenth century, especially geology, the history and modifications of the atmosphere, and the physiology of plants and animals. Despite new and accurate instruments I was disappointed, and most scientists would agree with me, that while the number of precise instruments multiplied we were still ignorant of the height of so many mountains and plains; of the periodical oscillations of the aerial oceans; the limit of perpetual snow under the polar caps and on the borders of the torrid zones; the variable intensity of magnetic forces; and many equally important phenomena.

If you compare the Río Negro with the Amazon, the River Plate or the Orinoco it is but a river of the second order. Possessing it has been, for centuries, of great political interest for the Spanish Government because it affords its rivals, the Portuguese, easy access into the Guianan missions to worry the Capitanía-General of Caracas in its southern limits. Three hundred years have passed in pointless territorial disputes. In different times, according to their degree of civilization, people have leaned either on papal authority or on astronomy. As they have generally been keener to prolong this dispute rather than solve it, only nautical science and geography have gained anything. When the affairs of Paraguay and the possession of the Sacramento colony became important for the two Courts of Madrid and Lisbon, commissioners were sent out to study the boundaries of the Orinoco, Amazon and River Plate. Besides the idle, who filled archives with their complaints and lawsuits, there were a few educated engineers and some naval officers acquainted with the means of determining the position of a place. The little we knew up to the of the last century about the geography of the interior of the Continent is due to these hard-working men. It is pleasing to remind ourselves that the sciences gained accidentally from these border commissions, often forgotten by the states that sent them out.

Under such favorable circumstances, and crossing regions long unknown to most European nations, including Spain itself, Bonpland and I collected a considerable number of materials, which when published may throw light on the history of nations, and on our knowledge about nature. Our research developed in so many unpredictable directions that we could not include everything in the form of a travel journal, and have therefore placed our observations in a series of separate works.

At midday we stopped at a deserted spot called Algodonal. I left my companions while they beached the boat and prepared the meal. I walked along the beach to observe a group of crocodiles asleep in the sun, their tails, covered with broad scaly plates, resting on each other. Small herons, as white as snow, walked on their hacks, even on their heads, as if they were tree trunks. The crocodiles were grey- green, their bodies were half covered in dried mud. From their color and immobility they looked like bronze statues. However, my stroll almost cost me my life. I had been constantly looking towards the river, and then, on seeing a flash of mica in the sand, I also spotted fresh jaguar tracks, easily recognizable by their shape. The animal had gone off into the jungle, and as I looked in that direction I saw it lying down under the thick foliage of a ceiba, eighty steps away from me. Never has a tiger seemed so enormous.

The vegetation in the plain surrounding the city is monotonous, although remarkably fresh due to the humidity. Its principal feature is an arborescent solanum, the Urtica baccifera, which reaches 40 feet tall, and a new species of the Guettarda genus. The ground is very fertile and could be easily watered if irrigation ditches were dug from the numerous rivers that do not dry up all year round. The most precious product in the zone is tobacco; it is solely to this plant that the small, badly built city owes its meager fame. Since the introduction of the royal monopoly (Estanco Real de Tabaco) in 1799 the cultivation of this plant in the Cumanà province is limited almost exclusively to the Cumanacoa valley. This monopolistic farming system is deeply hated by the people. The entire tobacco harvest has to be sold to the government, and to prevent or limit smuggling tobacco was concentrated in only one place. Inspectors travel the country burning plantations found outside the authorized zone, and inform against those wretches who dare to smoke their own home-made cigars. These inspectors are mostly Spaniards, as insolent as those doing the same job in Europe. This insolence has greatly contributed to the maintenance of the hatred between the colonies and the metropolis. (50)

The plain, or rather tableland, on which Cumanacoa stands is only 104 toises above sea-level, three or four times lower than the inhabitants of Cumanà, who have an exaggerated view of how cold it is up there, think it is. The climatic difference between the two neighboring towns is due less to the height of one of them than to local weather conditions. Among these causes are the proximity of the jungle, the frequency of rivers falling down narrow valleys, the amount of rain and those thick fogs that block out sunlight. The cool climate surprises us all the more because, as in the town of Cartago, at Tomependa on the Amazon, as in the Agarua valleys west of Caracas, very great heat is felt though the height varies between 200 and 480 toises above sea-level. In plains, as well as on mountains, isothermal lines are not constantly parallel to the equator or the surface of the earth. Meteorology's great problem will be to determine the direction of these lines and variations due to local causes, and to discover the constant laws in the distribution of heat.