250 



banks of the Temi. I attribute this difference 

 to the proximity of the savannahs of the Lower 

 Guainia, which permits the free access of the 

 breeze, and which also by their radiation cause 

 a stronger ascendant current than lands co- 

 vered with forests. 



The temperature of Javita* is cooler than that 

 of Maypures, but considerably hotter than that 

 of the Guainia or Rio Negro. The centigrade 

 thermometer kept up in the day to twenty-six 

 or twenty-seven degrees; and in the night to 

 twenty-one degrees. The diurnal heat north of 

 the cataracts, and particularly, north of the 

 mouth of the Meta, was generally twenty-eight 

 or thirty degrees, and the nocturnal heat twenty- 

 five or twenty-six degrees. This diminution of 

 heat on the banks of the Atabapo, the Tuamini, 

 and the Rio Negro, is no doubt owing to the 

 long absence of the Sun, a sky constantly cloudy, 

 and the evaporation of a humid soil. I do not 

 speak of the refrigerant influence of the forests, 

 as furnishing in their innumerable leaves so 

 many thin substances, that grow cool by ra- 



* The 1st of May, at 19 h in the morning, therm, of Reau- 

 mur, 17*7°; hygr. of whalebone, 61° j cloudy : at noon th. 

 21*9° ; hygr. 48° ; sky serene : at 4* 30', th. 198° ; hygr. 

 55-5° : at 1\ th. 20 2° 5 hygr. 60°: at 10h, th. I9 # ; 

 hygr. 62° ; cloudy : at 11**, th. 182« 5 hygr. 65*. The 3d 

 of May, at 20**, th. 19°; hygr. 63°; cloudy : at 0^, th. 

 21*5° ; hygr. 49° 5 clear : at 3& 15', th. 22° 5 hygr, 46*5<> : 

 at 8»>, th. 20-2° 5 hygr. 6l° ; cloudy. 



