436 DRAINING OF SWAMPS. 
employment too frequent, to require description, and I shall con- 
tent myself, for the moment, with a brief notice of some recent 
operations of this sort which are less generally known than their 
importance merits. 
Within the present century more than half a million acres 
of swamp-land have been drained and brought under cultiva- 
tion in Hungary, and works are in progress which will ulti- 
mately recover a still larger area for human use. The most 
remarkable feature of these operations, and at the same time 
the process which has been most immediately successful and 
remunerative, is what is called in Europe the regulation of 
water-courses, and especially of the River Theiss, on the lower 
course of which stream alone not less than 250,000 acres of pes- 
tilential and wholly unproductive marsh have been eonverted 
into a healthful region of the most exuberant fertility. 
The regulation of a river consists in straightening its channel 
by cutting off bends, securing its banks from erosion by floods, 
and, where necessary, by constructing embankments to confine 
the waters and prevent them from overflowing and stagnating 
upon the low grounds which skirt their current. In the course 
of the Theiss about sixty bends, including some of considerable 
length, have been cut off, and dikes sufficient for securing the 
land along its banks against inundation have been constructed. 
Many thousand acres of land have been recently permanently 
improved in Italy by the draining of swamps, and extensive 
operations have been projected and commenced on the lower 
Rhone, and elsewhere in France, with the same object.* 
* Very interesting and important experiments, on the practicability of wash- 
ing out the saltfrom seacoast lands too highly impregnated with that mineral 
to be fit for cultivation, are now in progress near the mouth of the Rhone, 
where millions of acres of marshy soil can easily be recovered, if these experi- 
ments are successful. 
See DuponcuEL, Traité @ Hydraulique et de Géologie agricoles. Paris, 1868, 
chap. xi. and xii. 
In the neighborhood of Ferrara are pools and marshes covering nearly two 
hundred square miles, or a surface more than equal to eight American town- 
ships. Centrifugal steam-pumps, of 2,000 horse-power, capable of discharging 
more than six hundred and fifty millions of gallons of water per day, have 
