snows, with the sole exception of the Paramos of Chita and Mucuchies,
than the Alps of Abyssinia. Snowy mountains are much more rare in the
torrid zone than is generally admitted; and the melting of the snows,
which is not copious there at any season, does not at all increase at
the time of the inundations of the Orinoco.

The cause of the periodical swellings of the Orinoco acts equally on
all the rivers that take rise in the torrid zone. After the vernal
equinox, the cessation of the breezes announces the season of rains.
The increase of the rivers (which may be considered as natural
pluviometers) is in proportion to the quantity of water that falls in
the different regions. This quantity, in the centre of the forests of
the Upper Orinoco and the Rio Negro, appeared to me to exceed 90 or
100 inches annually. Such of the natives, therefore, as have lived
beneath the misty sky of the Esmeralda and the Atabapo, know, without
the smallest notion of natural philosophy, what Eudoxus and
Eratosthenes knew heretofore,* that the inundations of the great
rivers are owing solely to the equatorial rains. (* Strabo lib. 17
page 789. Diod. Sic. lib. l c. 5.) The following is the usual progress
of the oscillations of the Orinoco. Immediately after the vernal
equinox (the people say on the 25th of March) the commencement of the
rising is perceived. It is at first only an inch in twenty-four hours;
sometimes the river again sinks in April; it attains its maximum in
July; remains at the same level from the end of July till the 25th of
August; and then decreases progressively, but more slowly than it
increased. It is at its minimum in January and February. In both
worlds the rivers of the northern torrid zone attain the greatest
height nearly at the same period. The Ganges, the Niger, and the
Gambia reach the maximum, like the Orinoco, in the month of August.*
(* Nearly forty or fifty days after the summer solstice.) The Nile is