The nature of the ground, and the junction of the Guaviare and Atabapo with the Orinoco, cause the latter to turn suddenly towards the north. In the absence of correct geographical knowledge, the Guaviare flowing in from the west was long regarded as the true origin of the Orinoco. The doubts raised by an eminent geographer, M. Buache, since 1797, as to the probability of a connection with the Amazons, have I hope been entirely refuted by my expedition. In an uninterrupted navigation of 920 geographical miles I passed through the singular network of rivers, from the Rio Negro, by the Cassiquiare, into the Orinoco; traversing in this manner the interior of the Continent, from the Brazilian boundary to the coast of Caraccas. In the upper portion of the basin of the Orinoco and its tributaries, between the 3rd and 4th degrees of north latitude, nature has several times repeated the enigmatical phenomenon of the so-called “black waters.” The Atabapo, whose banks are adorned with Carolinias and arborescent Melastomas, and the Temi, Tuamini, and Guainia, are all rivers of a coffee-brown colour. In the shade of the palm groves this colour seems almost to pass into ink-black. When placed in transparent vessels, the water appears of a golden yellow. The image of the Southern Constellations is reflected with wonderful clearness in these black streams. Where their waters flow gently, they afford to the observer, when taking astronomical observations with reflecting instruments, a most excellent artificial horizon. A cooler atmosphere, less torment from stinging mosquitoes, greater salubrity, and the absence of crocodiles (fish, however, are also wanting), mark the region of these black rivers. They probably owe their peculiar colour to a solution of carburetted hydrogen, to the luxuriance of the tropical vegetation, and to the quantity of plants and herbs on the ground over which they flow. On the western declivity of the Chimborazo, towards the coast of the Pacific, I remarked that the flooded waters of the Rio de Guayaquil gradually assumed a golden yellow or almost coffee-brown colour, when covering the meadows for some weeks. In the vicinity of the mouths of the Guaviare and Atabapo grows the Piriguao,[62] one of the noblest of palm trees, whose smooth and polished trunk, between 60 and 70 feet high, is adorned with a delicate flag-like foliage curled at the margins. I know no palm which bears such large and beautifully coloured fruits. They resemble peaches, and are tinged with yellow mingled with a roseate crimson. Seventy or eighty of them form enormous pendulous bunches, of which each tree annually ripens three. This fine tree might be called the peach palm. The fleshy fruits are from the luxuriance of vegetation most often devoid of seeds, and offer to the natives a nutritious farinaceous food which, like plantains and potatoes, can be prepared in a variety of ways.