1833.] SALINE INCRUSTATIONS. 73 



poor ones, and in the morning they were soon exhausted from not 

 having had anything to drink, so that we were obliged to walk. 

 About noon the dogs killed a kid, which we roasted. I ate some 

 of it, but it made me intolerably thirsty. This was the more 

 distressing as the road, from some recent rain, was full of little 

 puddles of clear water, yet not a drop was drinkable. I had 

 scarcely been twenty hours without water, and only part of the 

 time under a hot sun, yet the thirst rendered me very weak. How 

 people survive two or three days under such circumstances, I 

 cannot imagine : at the same time, I must confess that my guide 

 did not suffer at all, and was astonished that one day's deprivation 

 should be so troublesome to me. 



. I have several times alluded to the surface of the ground being 

 incrusted with salt. This phenomenon is quite different from that 

 of the salinas, and more extraordinary. In many parts of South 

 America, wherever the climate is moderately dry, these incrusta- 

 tions occur ; but I have nowhere seen them so abundant as near 

 Bahia Blanca. The salt here, and in other parts of Patagonia, 

 consists chiefly of sulphate of soda with some common salt. As 

 long as the ground remains moist in these salitrales (as the 

 Spaniards improperly call them, mistaking this substance for 

 saltpetre), nothing is to be seen but an extensive plain composed 

 of a black, muddy soil, supporting scattered tufts of succulent 

 plants. On returning through one of these tracts, after a week's 

 hot weather, one is surprised to see square miles of the plain 

 white, as if from a slight fall of snow, here and there heaped up 

 by the wind into little drifts. This latter appearance is chiefly 

 caused by the salts being drawn up, during the slow evaporation 

 of the moisture, round blades of dead grass, stumps of wood, and 

 pieces of broken earth, instead of being crystallized at the bottoms 

 of the puddles of water. The salitrales occur either on level tracts 

 elevated only a few feet above the level of the sea, or on alluvial 

 land bordering rivers. M. Parchappe * found that the saline 

 incrustation on the plain, at the distance of some miles from the 

 sea, consisted chiefly of sulphate of soda, with only seven per cent, 

 of common salt ; whilst nearer to the coast, the common salt in- 

 creased to 37 parts in a hundred. This circumstance would tempt 

 one to believe that the sulphate of soda is generated in the soil, 



* Voyage dans 1'Amerique Mcricl par M. A. d'Orbigny. Part. Hist. 

 torn. i. p. CG4. 



