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.

The moment the sticky sap of the kiracaguero tree is poured into the poisonous and concentrated liquid, kept boiling, it blackens and coagulates to become rather like tar or a thick syrup. This mass is the curare that is sold inside crescentia fruit; but as its preparation is in the hands of a few families, first-class curare from Esmeralda and Mandavaca is sold at high prices. When dried this substance looks like opium, but it attracts humidity if exposed to air. It tastes agreeably bitter, and Bonpland and I have often swallowed little bits. There is no danger as long as you make sure your gums and lips are not bleeding. The Indians regard curare taken by mouth as an excellent stomachic. The way the poison is made is rather similar everywhere, but there is no certainty that different poisons sold under the same name in the Orinoco and Amazon are identical or from the same plant.

It is neither from Virginia nor South America that Europe received in 1559 the first tobacco seeds, as is erroneously stated in most botanical books, but from the Mexican province of Yucatan. The man who boasted most about the fertility of the Orinoco banks, the famous Raleigh, also introduced smoking tobacco to the northern peoples. Already by the end of the sixteenth century there were bitter complaints in England 'of this imitation of wild Indian manners'. They thought that by smoking tobacco 'Englishmen would degenerate into a barbarous state'.

Opposite Bermúdez's farm two spacious caves open out of Cuchivano's crevice. At times flames, which can be seen from great distances, burst out. They illuminate the surrounding mountains, and from the mark left on the rocks by these burning gases we could be tempted to believe they reach some 100 feet high. During the last violent Cumanà earthquake this phenomenon was accompanied by long, dull, underground noises.

Hardly twenty-two months had passed since a previous earthquake had nearly destroyed the city of Cumanà. The people regard the reddish mist veiling the sky and the absence of a sea breeze at night as infallible ill omens. Many people came to see us to ask if our instruments predicted any further quakes. Their anxiety increased greatly when on the 5th of November, at the same time as the day before, there was a violent gust of wind, accompanied by thunder and a few raindrops. But no shock was felt.

Until the middle of the last century the mountains surrounding the Aragua valley were covered in forests. Huge trees of the mimosa, ceiba and fig families shaded the lake shore and kept it cool. The sparsely populated plain was invaded by shrubs, fallen tree trunks and parasitical plants, and was covered in thick grass so that heat was not lost as easily as from cultivated ground, which is not sheltered from the sun's rays. When the trees are felled, and sugar cane, indigo and cotton are planted, springs and natural supplies to the lake dry up. It is hard to form a fair idea of the enormous amount of evaporation taking place in the torrid zone, especially in a valley surrounded by steep mountains where maritime breezes blow, and whose ground is completely flat as if leveled by water. The heat prevailing on the lake shore is comparable to that in Naples and Sicily.

After dividing all that belongs to astronomy, botany, zoology, the political description of New Spain, and the history of the ancient civilizations of certain New World nations into separate works, many general results and local descriptions remained left over, which I could still collect into separate treatises. I had prepared several during my journey; on races in South America; on the Orinoco missions; on what hinders civilization in the torrid zone, from the climate to the vegetation; the landscape of the Andes compared to the Swiss Alps; analogies between the rocks of the two continents; the air in the equinoctial regions, etc. I had left Europe with the firm decision not to write what is usually called the historical narrative of a journey, but just to publish the results of my researches. I had arranged the facts not as they presented themselves individually but in their relationships to each other. Surrounded by such powerful nature, and all the things seen every day, the traveler feels no inclination to record in a journal all the ordinary details of life that happen to him.