212 CATARACTS OF THE ORINOCO. 



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 com- 

 parison of the enormous rivers which intersect the con- 

 tinent 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 croco- 

 diles, 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 cele- 

 brated 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 west- 

 ward from Trench Guiana towards the Andes of New 



