638 



stars at Uruana. I found the latitude of the 

 mission to be 7° 8' ; but the results from different 

 stars left a doubt of more than 1'. The stratum 

 of moschettoes, which hovered over the ground, 

 was so thick, that I could not succeed in recti- 

 fying properly the artificial horizon. I tor- 

 mented myself in vain ; and regretted, that I 

 was not provided with a mercurial horizon. On 

 the 7th of June, good absolute altitudes of the 

 Sun* gave me 69° 40' for the longitude. We 

 had advanced from Esmeralda 1° 17' toward 

 the west, and this chronometric determination 

 merits entire confidence, on account of the dou- 

 ble observations, made in going and returning, 

 at the Great Cataracts, and at the confluence of 

 the Atabapo and of the A pure. 



The situation of the mission of Uruana is ex- 

 tremely picturesque. The little Indian village 

 is placed at the foot of a lofty granitic mountain. 

 Rocks every where appear in the form of pillars 

 above the forest, rising higher than the tops of 

 the tallest trees. The Oroonoko no where dis- 



* The partial heights do not differ 2". In these places, 

 filled with venomous insects, observations are made most 

 favourably by day. The meridian altitudes of the Sun may 

 be taken by means of a reflecting instrument, in which the 

 parallelism of the great and little mirror corresponds with a 

 point of the limb twenty-five or thirty degrees beyond the 

 commencement of the division. (Obs. Mr., vol. i, p. 15, 

 222, 262, and 272.) 



