The Orinoco is narrower at its mouth than either the River Plate or the Amazons; and its length, according to positions astronomically determined by me, only amounts to 1120 geographical miles. But, on the other hand, far in the interior of Guiana, 560 miles from its mouth, I still found its breadth, when full, 16200 Parisian (17265 Eng.) feet. The periodical swelling of the river annually raises its level at this part of its course from 30 to 36 feet above its lowest level. Sufficient materials for an accurate comparison of the enormous rivers which intersect the continent of South America are still wanting. For such a comparison it would be needful to know in each case the profile of the river-bed, and the velocity of the water, which differs very greatly in different parts of the same stream. If, in the Delta enclosed by its variously divided and still unexplored arms,--in the regularity of its periodical rise and fall--and in the number and size of its crocodiles,--the Orinoco shews points of resemblance to the Nile, there is this further analogy between the two rivers, that after long rushing rapidly through many windings between wood-fringed shores formed by granitic and syenitic rocks and mountains, during the remainder of their course they slowly roll their waters to the sea, between treeless banks, over an almost horizontal bed. An arm of the Nile (the Green Nile, Bahr-el-Azrek) flows from the celebrated mountain-lake near Gondar, in the Abyssinian Gojam Alps, to Syene and Elephantis, through the mountains of Shangalla and Sennaar. In a similar manner the Orinoco rises on the southern declivity of the mountain chain which, in the 4th and 5th parallel of North latitude, extends westward from French Guiana towards the Andes of New Granada. The sources of the Orinoco[58] have never been visited by any European, or even by any natives who have been in communication with Europeans. In ascending the Upper Orinoco in the summer of 1800, we passed the Mission of Esmeralda, and reached the mouths of the Sodomoni and the Guapo. Here rises high above the clouds the massive summit of the Yeonnamari or Duida, a grand and picturesque mountain which presents to the spectator one of the finest scenes of nature which the tropical world has to offer. Its altitude, according to my trigonometrical measurement, is 8278 (8823 Eng.) feet above the level of the sea. The southern slope of the mountain presents a treeless grassy surface, and the humid evening air is filled far and wide with the fragrance of the ripe ananas. The stalks of the pine apples, swelling with rich juice, rise between the lowly herbs of the meadow, and the golden fruit is seen shining at a distance from under its leafy crown of bluish-green. Where mountain springs or rivulets break forth from the turfy covering, the scene is further adorned by groups of tall fan-palms, whose foliage never feels the influence of a cool breeze.