AMAZON-STONES—CASIQUIARE. 267 
The form usually given to them is that of the Perse- 
politan cylinders longitudinally perforated. These 
hard substances denote a degree of civilisation supe- 
rior to that of the present inhabitants, who, so far 
from being able to cut them, imagine that they are 
naturally soft when taken out of the earth, and 
harden after they have been moulded by the hand. 
They were found to be jade or saussurite, approach- 
ing to compact felspar, of a colour passing from 
apple to emerald green, translucent on the edges, 
and taking a fine polish; but the substance usually 
called Amazon-stone in Europe is different, be- 
ing a common felspar of a similar colour, coming 
from the Uralian Mountains and Lake Onega in 
Russia. 
Connected with this mineral are the warlike wo- 
men, whom the travellers of the sixteenth century 
named the Amazons of the New World; and re- 
garding whom Humboldt found no satisfactory ac- 
counts, although he is disposed to believe that their 
existence was not merely imaginary. 
The travellers passed three days at San Carlos, 
watching the greater part of each night, in the hope 
of seizing the moment of the passage of some star 
over the meridian ; but the sky was continually 
obscured by vapours. On the 10th May they em- 
barked a little before sunrise to go up the Rio Negro. 
The morning was fine, but as the heat increased the 
firmament became darkened. Passing between the 
islands of Zaruma and Mibita, covered with dense 
vegetation, and ascending the rapids of the Piedra 
de Uinumane, they entered the Casiquiare at the 
distance of 9} miles from the fort of San Carlos. 
The rock at the rapids was granite, traversed by 
