324 
COLOUR AT THE TIME OF INUNDATIOHS. 
the water, jield an extractive matter, that is brown, bitter, 
and mucilaginous ; but how many tufts of smilax have we 
seen in places, where the waters were entirely white. In 
the marshy forest which we traversed, to convey our canoe 
from the 'Bio Tuamini to the Cano Pimichin and the Bio 
Negro, why, in the same soil, did we ford alternately rivulets 
of black and white water? Why did we find no river 
white near its springs, and black 'in the lower part of its 
course? I know not whether the Bio Negro preserves its 
yellowish brown colour as far as its mouth, notwithstanding 
the great quant ity of white water it receives from the Cassi- 
quiare and the Bio Blanco. 
Although, on account of the abundance of rain, vege- 
tation is more vigorous close to the equator than eight or 
ten degrees north or south, it cannot be affirmed, that the 
rivers with black waters rise principally in the most shady 
and thickest forests. On the contrary, a great number ot 
the aquas negras come from the open savannahs that extend 
from the Meta beyond the G-uaviare towards the Caqueta- 
In a journey which I made with Senor Moutufar from the 
port of Guayaquil to theBodegas de Babaojo, at the period ot 
the great inuudations, I was struck by the analogy of colour 
displayed by the vast savannahs of the Invernadero del Garza 
and of the Lagartero, as well as by the Bio Negro and the 
Atabapo. These savannahs, partly inundated during three 
months, are composed of paspalum, erioqhloa, and several 
species of cyperace®. Wc sailed on waters that were fro® 
four to five feet deep ; their temperature was by day fro® 
33° 34° of the centigrade thermometer; they exhaled » 
strong smell of sulphuretted hydrogen, to which no dou» 
some rotten plants of arum and helieonia, that swain on th 
surface of the pools, contributed. The waters of the Lagcvrt ei 
were of a golden yellow by transmitted, and coffee-brown 
reflected light. They are no doubt coloured by a carbure 
of hydrogen. An analogous phenomenon is observed in <®® 
dunghill -waters prepared by our gardeners, and in j® 
waters that issue from bogs. May we not also admit, th»^ 
it is a mixture of carbon and hydrogen, an extractive veg® 
table matter, that colours the black rivers, the Atabapo, 1® . 
Zama, the Mataveni, and the Guainia? The frequency ° 
of the equatorial ra ins contributes no doubt to this color' • 
