563 



koned between Guayramerim * and the fa- 

 mous Salto of Theotonio-f-) indicate no rocky 

 ridges beyond the parallel of 8°. The prin- 

 cipal depression of the basin of which we 

 have just examined the outline, is not found 

 ( near one of its banks, as in the basin of the 

 Lower Oroonoko, but at the center, where 

 the great recipient of the Amazon forms a 

 longitudinal furrow inclined from west to 

 east, under an angle of at least 25 seconds J. 

 The barometric measures which I made at 

 Javita on the banks of the Tuamini, at Vasiva 

 on the banks of the Cassiquiare, and at the 

 cataract of Rentema, in the Upper Marag- 

 non, seem to prove that the rising of the 

 plains of the Amazon towards the north (at 

 the foot of the Sierra Parime), is 150 toises, 

 and, towards the west (at the foot of the Cor- 

 dillera of the Andes of Loxa), is 190 toises, 

 above the level of the Ocean It is to be 

 hoped, that when steam-boats go up the 

 Amazon from Grand Para as far as Pongo 



* Above the confluence of the Madeira and Mamore, which 

 a Brazilian journal, justly esteemed (Patriota, 1813, p. 288), 

 places in 10° 22' 30" of latitude, while it marks the con- 

 fluence of the Madeira with the Guapore, at 11° 54' 46*- 



+ Above the confluence of the Madeira and the Jamary. 



J See above, Vol. vi, p. 395, note. 



§ Vol. v, p. 251, 347, 550, 551, and Rec. d'Obs. Astr, 

 Vol. i. p. 315. 



2 p 2 



