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484 LIFE.
culture on the ocean domain take place in these districts on a very extensive scale. In the same way, in Belgian and French Flanders, in the
neighborhood of Ostend, Dunkirk, and Calais, the vmtteringhes have been
reclaimed from the North Sea. Near Etaples, the inland sea of Ponthieu
or Marquenterre has been changed into fine cultivated fields; and between the mouths of the Loire and the Charente the marsh-lands are everywhere protected by dikes and intersected by ditches, which are crossed
by the country people, both male and female, by means of their long leap-
ing-poles. To the south of the Gironde there are also some " small imitations of Flanders," and in the Landes the lake of Orx has been recently
drained by the same kind of operation as that adopted in the sea of
Haarlem.
In Holland and all the other countries bordering on the North Sea it is
only necessary to throw up dikes round, and to drain the marshy tracts
by the sea-shore, and they will be converted into fertile fields, fit, after
a few years, for any crops which the climate allows. On the coasts of
the Mediterranean, Caspian, and other seas, another course has to be
adopted. In these districts the tracts of ground which have formerly
been inundated by salt-water always remain more or less saturated with
salt, and are unfitted for any permanent course of cultivation. Thus, instead of turning them into cultivated fields, it is found better worth while
in many spots to utilize them as salt-marshes. The salt-water, conducted
from one pond to another, evaporates in the sun, and ultimately leaves on
the bed of the last compartment a thin layer of salt, which the laborers
collect and pile up in great pyramids on the edge of the roads. This
manufacture assumes its chief importance on the shores of the Western
Mediterranean: certain salt-works on the sea-shore there produce from
ten to twenty thousand tons every year.
What is the cause which produces the contrast between the natural fertility of the polders of Holland and the sterility of the ground recovered
from the sea on the Mediterranean coasts ? The cause must first and
foremost be sought for in the greater or less supply of fresh-water which
washes the soil. On the shores of the North Sea the air is naturally
moist, and the quantity of rain-water which is showered down upon the
country is very considerable. The porous earth is constantly washed by
the rain, and all the soil on the surface is gradually carried away, so that
almost immediately they are surrounded by dikes the cultivation of the
polders may be commenced. It must be confessed that, on the shores of
the Mediterranean, the saline portions of the ground are likewise dissolved
and carried into the subsoil; but in consequence of evaporation, which is
very active in this climate, the water from the bottom ascends gradually through the porous earth together with the salt which it holds in solution, and then evaporates, leaving on the surface a crust, more or less
thick, of saline matter. A reciprocating motion is thus established between the surface and the deeper strata of the ground; the rain causes
the salt to descend, and evaporation causes it to rise again, while the sea-
| Title | The ocean, atmosphere, and life |
| Creator | Reclus, Elisée |
| Publisher | Harper |
| Place of Publication | New York |
| Date | 1873 |
| Language | eng |
| Type | Books/Pamphlets |
| Title | 00000533 |
| Type | Books/Pamphlets |
| Transcript | 484 LIFE. culture on the ocean domain take place in these districts on a very extensive scale. In the same way, in Belgian and French Flanders, in the neighborhood of Ostend, Dunkirk, and Calais, the vmtteringhes have been reclaimed from the North Sea. Near Etaples, the inland sea of Ponthieu or Marquenterre has been changed into fine cultivated fields; and between the mouths of the Loire and the Charente the marsh-lands are everywhere protected by dikes and intersected by ditches, which are crossed by the country people, both male and female, by means of their long leap- ing-poles. To the south of the Gironde there are also some " small imitations of Flanders," and in the Landes the lake of Orx has been recently drained by the same kind of operation as that adopted in the sea of Haarlem. In Holland and all the other countries bordering on the North Sea it is only necessary to throw up dikes round, and to drain the marshy tracts by the sea-shore, and they will be converted into fertile fields, fit, after a few years, for any crops which the climate allows. On the coasts of the Mediterranean, Caspian, and other seas, another course has to be adopted. In these districts the tracts of ground which have formerly been inundated by salt-water always remain more or less saturated with salt, and are unfitted for any permanent course of cultivation. Thus, instead of turning them into cultivated fields, it is found better worth while in many spots to utilize them as salt-marshes. The salt-water, conducted from one pond to another, evaporates in the sun, and ultimately leaves on the bed of the last compartment a thin layer of salt, which the laborers collect and pile up in great pyramids on the edge of the roads. This manufacture assumes its chief importance on the shores of the Western Mediterranean: certain salt-works on the sea-shore there produce from ten to twenty thousand tons every year. What is the cause which produces the contrast between the natural fertility of the polders of Holland and the sterility of the ground recovered from the sea on the Mediterranean coasts ? The cause must first and foremost be sought for in the greater or less supply of fresh-water which washes the soil. On the shores of the North Sea the air is naturally moist, and the quantity of rain-water which is showered down upon the country is very considerable. The porous earth is constantly washed by the rain, and all the soil on the surface is gradually carried away, so that almost immediately they are surrounded by dikes the cultivation of the polders may be commenced. It must be confessed that, on the shores of the Mediterranean, the saline portions of the ground are likewise dissolved and carried into the subsoil; but in consequence of evaporation, which is very active in this climate, the water from the bottom ascends gradually through the porous earth together with the salt which it holds in solution, and then evaporates, leaving on the surface a crust, more or less thick, of saline matter. A reciprocating motion is thus established between the surface and the deeper strata of the ground; the rain causes the salt to descend, and evaporation causes it to rise again, while the sea- |
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