208 DEPOPULATION OF THE MISSIONS. 



travellers, without entirely crediting- this assertion, 

 usually took care to avoid the black rocks at night. 

 But the danger of reposing on them, Humboldt 

 thinks, may rather be owing to the very great degree 

 of warmth they retain during the night, which was 

 found to be 85'5, while that of the air was 78'8. 

 In the day their temperature was 118'4, and the 

 heat which they emitted was stifling. 



Among the causes of the depopulation of the 

 missions, Humboldt mentions the general insalubrity 

 of the climate, bad nourishment, want of proper 

 treatment in the diseases of children, and the prac- 

 tice of preventing pregnancy by the use of dele- 

 terious herbs. Among the savages of Guiana, when 

 twins are produced one is always destroyed, from 

 the idea that to bring more than one at a time into 

 the world is to resemble rats, opossums, and the 

 vilest animals ; and that two children born at once 

 cannot belong to the same father. When any phy- 

 sical deformity occurs in an infant, the father puts 

 it to death, and those of a feeble constitution some- 

 times undergo the same fate, because the care which 

 they require is disagreeable. " Such," says Hum- 

 boldt, " is the simplicity of manners, the boasted 

 happiness of man in the state of nature ! He kills 

 his son to escape the ridicule of having twins, or 

 to avoid travelling more slowly, in fact to avoid a 

 little inconvenience." 



The two great cataracts of the Orinoco are formed 

 by the passage of the river across a chain of granitic 

 mountains, constituting part of the Parime range. 

 By the natives they are called Mapara and Quittuna; 

 but the missionaries have denominated them the 

 falls of Atures and Maypures, after the first tribes 

 which they assembled in the nearest villages. They 

 are only forty-one miles distant from each other, 

 and are not more than 345 miles west of the qpr- 

 dilleras of New-Grenada. They divide the Chris- 

 tian establishments of Spanish Guiana into two un- 



