1833.] 11. NEGRO TO R. COLORADO. 63 



live iu countless numbers in the brine-pans at Lyrniiigton : but 

 only in those in which the fluid has attained, from evaporation, 

 considerable strength namely, about a quarter of a pound of salt 

 to a pint of water. Well may we affirm that every part of the 

 world is habitable ! Whether lakes of brine, or those subterranean 

 ones hidden beneath volcanic mountains warm mineral springs 

 the wide expanse and depths of the ocean the upper regions of 

 the atmosphere, and even the surface of perpetual snow all 

 support organic beings. 



To the northward of the Eio Negro, between it and the inhabited 

 country near Buenos Ayres, the Spaniards have only one small 

 settlement, recently established at Bahia Blanca. The distance in 

 a straight line to Buenos Ayres is very nearly five hundred British 

 miles. The wandering tribes of horse Indians, which have always 

 occupied the greater part of this country, having of late much 

 ' harassed the outlying estaneias, the government at Buenos Ayres 

 equipped some time since an army under the command of General 

 Rosas for the purpose of exterminating them. The troops were 

 now encamped on the banks of the Colorado ; a river lying about 

 eighty miles northward of the Rio Negro. "When General Rosas 

 left Buenos Ayres he struck in a direct line across the unexplored 

 plains : and as the country was thus pretty well cleared of Indians, 

 he left behind him, at wide intervals, a small party of soldiers with 

 a troop of horses (a posta), so as to be enabled to keep up a com- 

 munication with the capital. As the Beagle intended to call at 

 Bahia Blanca, I determined to proceed there by land ; and ulti- 

 mately I extended my plan to travel the whole way by the postas 

 to Buenos Ayres. 



August llth. Mr. Harris, an Englishman residing at Patagones, 

 a guide, and five Gauchos who were proceeding to the army on 

 business, were my companions on the journey. The Colorado, as I 



above the waters of the sea. Iu both countries the salt-lakes occupy 

 shallow depressions in the plains ; in both the mud on the borders is black 

 and fetid ; beneath the crust of common salt, sulphate of soda or of magnesia 

 occurs, imperfectly crystallized; and in both, the muddy s.md is mixed 

 with lentils of gypsum. The Siberian salt-lakes are inhabited by small 

 crustaccous animals ; and flamingoes (Edin. New Philos. Jour., Jan. 1830) 

 likewise frequent them. As these circumstances, apparently HO trifling, 

 occur in two distant continents, we may feel sure that they are the 

 necessary results of common causes. f?ec Pallas' 8 Travels, 1793 to 179-1, 

 pp. 129-i:ji. 



