500 



nautical miles. This is eight times the breadth 

 of the Nile at Manfalout and Syout *, yet we 

 were at the distance of a hundred and ninety- 

 four leagues from the mouth of the Oroonoko. 



The temperature of the water at it's surface 

 was 27*8° of the centigrade thermometer, near 

 Uruana. That of the river Zara, or Congo, in 

 Africa, at an equal distance from the equator -f, 

 was found by Captain Tuckey, in the months of 

 July and August, to be only from 23*9° to 25*6°. 

 We shall hereafter see, that the waters of the 

 Oroonoko, as well near the banks, where they 

 flow beneath a thick shade, as in the channel in 

 the middle of the river, rise to 29*5° %, and never 

 sink below 27*5° §; but the air also at this 

 period, from April to June, was generally be- 

 tween 28° and 30° in the day, and at night be 

 tween 24° and 26°, while in the valley of Congo 

 the temperature kept, from eight in the morning 

 till noon, between 20 6° and 26*7°. 



The western bank of the Oroonoko remains 

 low farther than the mouth of the Meta; while 

 from the mission of Uruana the mountains ap- 

 proach the eastern bank more and more. As 

 the strength of the current increases in propor- 

 tion as the river grows narrower, the progress of 



* Giraud, sur la Faille d' Egypt, p. 12. 

 + In the southern hemisphere, 

 % As high as 23-6° R. 

 § 22 0° R. 



