76 



RIO NEGRO. 



Aug. 1833. 



margin is from four to five inches thick^ but towards the 

 centre its thickness increases. This lake was two and a half 

 miles long^ and one broad. Others occur in the neighbour- 

 hood many times larger^ and with a floor of salt^ two and three 

 feet in thickness^ even when under water during the winter. 

 One of these brilliantly- white and level expanses^ in the 

 midst of the brown and desolate plain^ offers an extraordinary 

 spectacle. A large quantity of salt is annually drawn from 

 the salina ; and great piles^ some hundred tons in weight, 

 were lying ready for exportation. It is singular that the 

 salt, although well crystallized, and appearing quite pure, does 

 not answer so well for preserving meat as sea salt from the 

 Cape de Verd Islands. Although the latter is necessarily 

 much dearer, it is constantly imported and mixed with the 

 salt procured from these salinas. A merchant at Buenos 

 Ayres told me that he considered the Cape de Verd salt 

 worth fifty per cent, more than that from the Rio Negro. 

 The season for working the salinas forms the harvest of 

 Patagones ; for on it, the prosperity of the place depends. 

 Nearly the whole population encamps on the banks of the 

 river, and the people are employed in drawing out the salt 

 in bullock-waggons. 



The border of the lake is formed of mud : and in this nume- 

 rous large crystals of gypsum, some of which are three inches 

 long, lie embedded; whilst on the surface, others of sulphate 

 of magnesia lie scattered about. The Gauchos call the former 

 the Padre del sal," and the latter the " Madre^^ ; they state 

 that these progenitive salts always occur on the borders of 

 the salinas, when the water begins to evaporate. The mud w 

 is black, and has a fetid odour. I could not, at first, ima- 

 gine the cause of this, but I afterwards perceived that the 

 froth, which the wind drifted on shore was coloured green^ as 

 if by confervee : I attempted to carry home some of this 

 green matter, but from an accident failed. Parts of the lake 

 seen from a short distance appeared of a reddish colour, 

 and thisj perhaps, was owing to some infusorial animalcula. 

 The mud in many places was thrown up by numbers of 



