555 



pressed by two hundred and twenty-seven oscil- 

 lations in ten minutes of time ; an increase of 

 force* that would seem to indicate some local 

 attraction. Yet the blocks of the granite black- 

 ened by the waters of the Oroonoko have no 

 perceptible action upon the needle. The baro- 

 metric height at noon was 336*6 lines-}-; the 

 centigrade thermometer being at 30*6° in the 

 shade. The temperature of the air at night 

 lowered to 26*2° ; the hygrometer of Deluc keep- 

 ing at 46°. 



The river had risen several inches in the day r 

 on the 1 0th of April ; this phenomenon surprised 

 the natives so much the more, as the first swel- 

 lings are almost imperceptible, and are usually 

 followed in the month of April by a fall for some 

 days. The Oroonoko was already three feet 

 higher than the level of the lowest waters. The 

 natives showed us on a granitic wall the traces 

 of the great rise of the waters of late years. We 

 found them to be forty-two feet X high, which is 



* See aLove, chap, xviii^ p. 416. The latitude of Carichana, 

 deduced from that of TJruana and of the mouth of the Meta, 

 is 6° 29 7 . 



+ The barometer, in the port of Carichana, kept at six in 

 the evening, at 335*7 lines 3 the thermometer in the open air, 

 at 2C> 8°. See above, p. 455. 



t Or thirteen metres and half. The height of the mean 

 rise of the Nile is fourteen cubits of the Nilometer of Elephan- 

 tino, or 7 '41 metres. 



