110 M. Humboldt oti the Waters of the Rio Vinagre 



rounded with a quickset hedge of narrow-leaved euphorbium 

 {lechero) of the most delicate green. This beautiful verdure 

 contrasts in a striking manner with the back-ground of black 

 and arid mountains which surround the volcano, and which 

 are rent by the effects of the earthquakes. 



The site of the village is celebrated in the country on account 

 of three beautiful cascades [choreras) of the river of Pusambio, 

 whose water is acid, and which the people, who know no other 

 acid than vinegar, call Rio Vinagre, sometimes G?-«w Vinagre. 

 This river takes its rise at the height of nearly 10,871 feet, in 

 a very inaccessible spot. Although the temperature of the 

 water be little different in the lower cascades from that of the 

 surrounding atmosphere, it is not less certain that the sources 

 of the Rio Pusambio or Vinagre are very hot. This fact was 

 attested to me by the natives and by the missionary of the 

 village of Purace. In going to the summit of the volcano I 

 saw a column of smoke rise at the place where the acid waters 

 make their appearance. I have drawn the second of the falls 

 of the Vinagre (plate xxx. of the Views of the Cordilleras) : 

 the water, which opens itself a passage across a cavern, is 

 precipitated more than 383 feet in depth. The fall has a very 

 picturesque effect ; but the inhabitants of Popayan would be 

 better pleased if the river, instead of throwing itself into the 

 Rio Cauca, became engulfed in some other crevice ; for such 

 is the delicacy of constitution of animals which breathe by 

 gills, and which absorb the oxygen dissolved in the water, that 

 the Cauca during a course of four leagues is destitute of fish, 

 on account of the mixture of its waters with those of the Rio 

 Vinagre*, which are charged both with oxide of iron and with 

 sulphuric and muriatic acid. After staying a considerable 

 time on the craggy wall of rock which borders the cascade, 

 a pricking sensation is felt in the eyes from the minute spray 

 jn the atmosphere. Fish re-appear in the Rio Cauca at the 

 point where it becomes enlarged by the influx of the Pinda- 

 mon and of the Palace f. 



A little to the north of the sources of the Pusambio rise 

 two other rivulets charged in like manner with free sulphuric 

 acid, which the people call the Little Vinegars [los dos Vinagres 

 chicos) : they throw themselves into the Rio de San Francisco, 

 which is itself but a tributary of the Gran Vinagre. During 

 my stay at Popayan, it was an opinion generally received 

 that all these acid waters contained some iron dissolved by a 



• M. Caldas has even attributed to this mixture, doubtless with little 

 reason, the absence of goitres in the valley of Rio CMic?i. — Semmiario, t. i. 

 p. 265. See my Memoir on the Goitres in the Cordilleras.— (Afi^enrfit, 

 Jour, de Pkt/swl. t. iv. p. 109.) t Journal de Physique, t. Ixii. p. 61. 



jireat 



