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 incrustations 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 the
salitrales (as the Spaniards improperly call them, mistaking this
substance for saltpeter), 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 [7] 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 increased to 37 parts in a
hundred. This circumstance would tempt one to believe that the
sulphate of soda is generated in the soil, from the muriate, left on
the surface during the slow and recent elevation of this dry country.
The whole phenomenon is well worthy the attention of naturalists. Have
the succulent, salt-loving plants, which are well known to contain much
soda, the power of decomposing the muriate? Does the black fetid mud,
abounding with organic matter, yield the sulphur and ultimately the
sulphuric acid?
Two days afterwards I again rode to the harbour: when not far from our
destination, my companion, the same man as before, spied three people
hunting on horseback. He immediately dismounted, and watching them
intently, said, "They don't ride like Christians, and nobody can leave
the fort." The three hunters joined company, and likewise dismounted
from their horses. At last one mounted again and rode over the hill
74