CATAKACTS OF THE OBINOCO. 157 



Buenos Ayres. The Amazon, which is the longest of all 

 rivers, measures 2880 miles from its rise in the Lake of 

 Lauricocha to its estuary. Yet its width in the province 

 of Jaen de Bracamoros, near the cataract of Rentama, where 

 I measured it at the foot of the picturesque mountain 

 of Patachuma, is scarcely equal to that of the Rhine at 

 Mayence. 



The Orinoco is narrower at its mouth than either the La 

 Plata or the Amazon, while its length, according to ray 

 astronomical observations, does not exceed 1120 geographical 

 miles. But in the interior of Guiana, 560 miles from its 

 estuary, I found that at high water the width of the river 

 measured upwards of 17,265 feet. Its periodical swelling 

 here raises the level of the waters every year from 30 to 

 36 feet above the lowest water-mark. We are still with- 

 out sufficient data for an accurate comparison between the 

 enormous rivers which traverse the South American Con- 

 tinent. For such a comparison it would be necessary to 

 ascertain the profile of the river-bed, as well as the velo- 

 city of the water, which varies very considerably at different 

 points. 



If the Orinoco, in the Delta formed by its variously 

 divided and still unexplored branches, as well as in the regu- 

 larity of its rise and fall, and in the number and size of its 

 crocodiles, exhibits numerous points of resemblance to the 

 Nile; there is this further analogy between the two rivers, 

 that they for a long distance wind their impetuous way, like 

 forest torrents, between granitic and syenitic rocks, till, 

 slowly rolling their waters over an almost horizontal bed, 

 skirted by treeless banks, they reach the sea. 



An arm of the Nile (the Green Nile, Bahr-el-Azrek), from 

 the celebrated mountain lake, near Gondar, in the Gojam 

 Alps, in Abyssinia, to Syene and Elephantis, winds its way 

 through the mountain range of Schangalla and Sennar; and 

 m like manner the Orinoco rises on the southern slope of 



