345 



ters, almost identical with that of the Rio Con- 

 go, is very remarkable in the proximity of the 

 equator*. The Oroonoko, between four and 

 eight degrees of latitude, has generally from 

 27*5° "to 29*5° of temperature. The springs 

 which issue from the granite at Maypures are 

 at 27*8°. The decrease of heat, that is observed 

 in approaching the equator, is singularly con- 

 formable to the hypotheses of some naturalists 

 of antiquity-}-; it is however merely a local phe- 

 nomenon, less owing to the height of the ground, 

 than to a constantly rainy or cloudy sky, the 

 humidity of the soil, the thickness of the forests, 

 the evaporation of the plants, and the want of 

 sandy beaches adapted to concentrate caloric 



stantly cloudy. Height above the level of the sea, 125 

 toises. 



May. 



Barometer 



Thermometer 



Whalebone 



in lines. 



of Reaumur. 



Hygrometer. 



8 at 2l h 



328 2° 



17*7° 



54° 



9 at2l h 



3279 



175 



55 



at 21> l 30' 



328-2 



17-6 



57 



at 22^ 30' 



328 3 



17^ 



562 



at 0 h 



327 8 



18-2 



53 



at 3 h 30' 



327-6 



18-4 



513 



at 4 h 15' 



326-8 



18'2 



516 



at 5 h 45" 



3372 



18-2 



51-2 



The hygrometer kept up, while it did not rain, between 47° 

 and 60° Delue (83*4° and 90 2° Saussure). 



* In 1° 53' and 2° 15' north latitude. 



f Geminus Isag. in Aratum, c. 13. Strabo. Georgr., lib. 2, 

 p. 97. 



