324 COLOUR AT THE TIME OF INUNDATIONS. 



the water, /ield an extractive matter, that is browr, 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 Eio Tuamini to the Cafio Pimichin and the Rio 

 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 quantity of white water it receives from the Cassi- 

 quiare and the Eio 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 of 

 the aguas negras come from the open savannahs that extend 

 from the Meta beyond the Ghiaviare towards the Caqueta. 

 In a journey which I made with Senor Montufar from the 

 port of Guayaquil to theBodegas de Babaojo, at the period of 

 the great inundations, I was struck by the analogy of colour 

 displayed by the vast savannahs of the Invernadero del Oarzal 

 and of the Lagartero, as well as by the Eio Negro and the 

 Atabapo. These savannahs, partly inundated during three 

 months, are composed of paspalum, eriochloa, and several 

 species of cyperacese. "We sailed on waters that were from 

 four to five feet deep ; their temperature was by day from 

 33 34 of the centigrade thermometer; they exhaled a 

 strong smell of sulphuretted hydrogen, to which no doubt 

 some rotten plants of arum and heliconia, that swam on the 

 surface of the pools, contributed. The waters of the Lagartero 

 were of a golden yellow by transmitted, and coffee-brown by 

 reflected light. They are no doubt coloured by a carburet 

 of hydrogen. An analogous phenomenon is observed in the 

 dunghill-waters prepared by our gardeners, and in the 

 waters that issue from bogs. May we not also admit, that 

 it is a mixture of carbon and hydrogen, an extractive vege- 

 table matter, that colours the black rivers, the Atabapo, the 

 Zama, the Mataveni, and the G-uainia? The frequency of 

 of the equatorial rains contributes no doubt to this colora- 



