COMBINATION OF METHODS. 515 
Combination of Methods. 
Upon the whole, it is obvious that no one of the methods 
heretofore practised or proposed for averting the evils resulting 
from river inundations is capable of universal application. 
Each of them is specially suited to a special case. But the 
hydrography of almost every considerable river and its tribu- 
taries will be found to embrace most special cases, most 
known forms of superficial fluid circulation. For rivers, in 
general, begin in the mountains, traverse the plains, and end in 
the sea; they are torrents at their sources, swelling streams in 
their middle course, placid currents, flowing mollc flumine, at 
their termination. Hence in the different parts of their course 
the different methods of controlling and utilizing them may 
successively find application, and there is every reason to be- 
lieve that by a judicious application of all, every great river 
may, in a considerable degree, be deprived of its powers of 
evil and rendered subservient to the use, the convenience, and 
the dominion of man.* 
These short cuts are called salt, or leaps, and sometimes abridge the distance 
between their termini by several miles. In 1777, the salto of Cottaro short- 
ened a distance of 7,000 métres by 5,000, or, in other words, reduced the 
length of the river by five kilométres, or about three miles, and in 1807 and 
1810 the two salti of Mezzanone effected a still greater reduction. 
* On the remedies against inundation, see the valuable paper of Lom- 
BARDINI, Sulle Inondazioni avvenute in questi ultimi tempi in Francia. Milano, 
1858. 
There can be no doubt that in the case of rivers which receive their supply 
in a large measure from mountain streams, the methods described in a former 
chapter as recently employed in South-eastern France to arrest the formation 
and lessen the force of torrents, would prove equally useful as a preventive 
remedy against inundations. They would both retard the delivery of surface- 
water and diminish the discharge of sediment into rivers, thus operating at 
once against the two most efficient causes of destructive floods. See Chapter 
III., pp. 316 e segq. 
