live-clad
regions of Andalucia, as the Ebro divides the levels of Arragon.
Spain abounds with brackish streams, _Salados_, and with salt-mines,
or saline deposits, after the evaporation of the sea-waters. The
central soil is strongly impregnated with saltpetre: always arid, it
every day is becoming more so, from the singular antipathy which the
inhabitants of the interior have against trees. There is nothing to
check the power of evaporation, no shelter to protect or preserve
moisture. The soil becomes more and more baked and calcined; in some
parts it has almost ceased to be available for cultivation: another
serious evil, which arises from want of plantations, is, that the
slopes of hills are everywhere liable to constant denudation of soil
after heavy rain. There is nothing to break the descent of the
water; hence the naked, barren stone summits of many of the sierras,
which have been pared and peeled of every particle capable of
nourishing vegetation; they are skeletons where life is extinct. Not
only is the soil thus lost, but the detritus washed down either forms
bars at the mouths of rivers, or chokes up and raises their beds;
they are thus rendered liable to overflow their banks, and convert
the adjoining plains into pestilential swamps. The supply of water,
which is afforded by periodical rains, and which ought to support the
reservoirs of rivers, is carried off at once in violent floods,
rather than in a gentle gradual disembocation. The volume in the
principal rivers of Spain has diminished, and is diminishing. Rivers
which were navigable are so no longer; the artificial canals which
were to have been substituted remain unfinished: the progress of
deterioration advances, while little is done to counteract or amend
what every year must render more difficult and expensive, while the
means of repair and correction will diminish in equal proportion,
from the poverty occasioned by the evil, and by the fearful extent
which it will be allowed to attain. The rivers which are really
adapted to navigation are, however, only those which are perpetually
fed by those tributary streams that flow down from mountains which
are covered with snow all the year, and these are not many. The
majority of Spanish rivers are very scanty of water during the summer
time, and very rapid in t