DOWN THE RIO NEGRO 505 
often skirts the water with a permanent edge, not falling away in 
masses at the commencement of the dry season as on the Amazon, 
and especially on the Solimoes ; and when the river is low the 
steeply sloping bank, whether of rock or earth, is for miles un- 
interruptedly clad with rootlets from the bases of the trees which 
form to it a dense fringe. 
On the Amazon and Solimoes in the wet season, when the 
current in the river is most rapid, in the inundated forest on each 
side there is usually scarcely any current, and the farther the gap6 
is entered the stiller the water becomes. Each day as the river 
rises the inundation widens, but silently and insensibly. Should 
there be a slight fall in the ground, as there sometimes is towards 
an inland lake, then for a time there is a rapid flow from the river 
until the lake becomes filled to the level of the river. I have been 
entangled in one of these currents when we were glad to pull the 
montaria across it by catching hold of the twiners that hung from 
the trees, the oars being of scarcely any use. 
When the river, having reached its height, begins to descend, 
there is generally a perceptible flow from the gapo. The floating 
plants (various Marsileacese, Naiades, Ceratophylla, minute 
Hydrocharidese, and the new Euphorbiacea, Phyllanthus fliiitans) 
which had covered the still waters of the gapo during the rising 
flood, and had just attained perfection as the river reached its 
height, now begin slowly to move out, and I ha.ve observed them 
floating away throughout the breadth of the river, though from the 
masses being broken up and the minute size of the individuals, a 
voyager, whose attention had not previously been called to their 
existence, would hardly notice them. These little plants aflbrd 
shelter to several small univalve shells and to not a few winged 
and wingless insects, and in pushing the montaria through dense 
beds I have sometimes been startled by the springing up of a 
cloud of grasshoppers, nor is it infrequent to see the black snout 
of an alligator peering out and rapidly withdrawn as he becomes 
aware of the approach of his worst enemy, man. In some places 
the water is emptied out of the gap6 with great rapidity, as in the 
extreme angle between the Solimoes and Rio Negro, where the 
sound of the waters rushing against the trees is as that of a 
cataract. In passing this place by moonlight on my return from 
Manaquiry, I received several blows against the tree-trunks and 
had my clothes torn in many places. Instances like this are, 
however, rare, and the water in general subsides from the forest 
as placidly as it had entered it. 
It has been stated in Europe that the rapid rising of the waters 
of the Amazon causes trees to be torn down and sometimes large 
portions of earth to be carried away ; but all the falls of land and 
trees I have seen (and I have been witness of several) occurred 
shortly after the river began to ebb, and they are owing to the water 
