78 LITEBATUEE ON TOBEENTS. 



M. Connant might justly claim to be allowed to say, in defence of his 

 suggestion, that had the artificial bed been of a magnitude to contain the 

 whole flood, as was evidently requisite, the success might have been complete. 



In 1856 appeared, as has been already mentioned, the pamphlet of M. 

 Eozet, entitled Moyens de forcer les Torrents des Montagues de rendre v/ne 

 partie du sol quils ravagent, to which ■ reference has already been made. 

 " He proposes," say Marsh, " to commence with the amphitheatres in which 

 mountain torrents so often rise, by covering their slopes and iilling their 

 beds with loose blocks of rock, and by constructing at their outlets, and at 

 other narrow points in the channels of the torrents, permeable barriers of 

 the same material promiscuously heaped up, much according to the method 

 employed by the ancient Romans in their northern provinces for a similar 

 purpose. By this means, he supposes, the rapidity of the current would be 

 checked, and the quantity of transported pebbles and gravel — which, by 

 increasing the mechanical force of the water, greatly aggravate the damage 

 by floods — much diminished. When the stream has reached that part of 

 its course where it is bordered by soil capable of cultivation, and worth the 

 expense of protection, he proposes to place along one or both banks, according 

 to circumstances, a line of cubical blocks of stone or pillars of masonry 

 three or four feet high and wide, and at the distance of about eleven yards 

 from each other. The space between the two lines, or between a line and 

 the opposite high bank, would, of course, be determined by observation of 

 the width of the ^swift-water current at high floods. As an auxilliary 

 measure, small ditches and banks, or low walls of pebbles, should be con- 

 structed from the hue of blocks across the grounds to be protected, nearly 

 at right angles to the current, but slightly inclining downwards, and at 

 convenient distances from each other. Eozet thinks the proper interval 

 would be 300 yards, and it is evident that, if he is right in his main 

 principle, hedges, rows of trees, or even common fences, would in many 

 cases answer as good a purpose as banks and trenches or low walls. The 

 blocks or pillars of stone would, he contends, check the lateral cm-rents so 

 as to compel them to let fall all their pebbles and gravel in the main 

 channel — where they would be rolled along until ground down to sand or 

 silt — and the transverse obstructions would detain the water upon the soil 

 long enough to secure the deposit of its fertilizing slime. Numerous facts 

 are cited in support of the author's views, and I imagine there are few 

 residents of rural districts whose own observation will not furnish testimony 

 confirmatory of their soundness." 



He says, — " The plan of Eozet is recommended by its simplicity and 

 cheapness as well as its facility and rapidity of execution, and is looked 

 upon with favour by many persons very competent to judge in such 

 matters. It is, however, by no means capable of universal application, 

 though it would often doubtless prove highly useful in connection with the 

 measures now employed in south-eastern France." 



And he adds, in a foot-note,—" The eflTect of trees and other detached 

 obstructions in checking the flow of water is particularly noticed by Palissy 

 in his essay on Waters aiid Fountains, p. 173, edition of 1844. 'There be ' 

 says he, ' in divers parts of France, and specially at Nantes, wooden bridges 

 where, to break the force of the waters and of the floating ice, which might 

 endamage the piers of the said bridges, they have driven upright timbers 

 into the bed of the rivers above the said piers, without the which they 



