IMPROVEMEIS'T OF MOUTH OF MISSISSIPPI RITER, 89 



It is for this reason that we find tliat tlie Mississippi, wliicli at first 

 most naturally flowed in the lowest portion of the valley, is now at 

 places over fifteen feet above the abjacent flood plains. On the im- 

 provement of the Rhine, the entire river has been lowered as much 

 as six feet in places by increasing the slope by means of cut-offs, 

 and large tracts of land have been reclaimed which had become 

 entirely worthless. 



On the majority of "working-rivers," we find very little difier- 

 ence in the ultimate result, unless they are interfered with by arti- 

 ficial contrivances, or that the natural forces find a new field of 

 operations. After what has been observed, I will endeavor to re- 

 view what has been done up to the present time to remedy the 

 difl&culties arising from the detritus deposited at the mouths of 

 rivers. 



The first, and most natural conception, was to endeavor to im- 

 prove the natural outlets of the rivers, but this plan has been at- 

 tended with varied results, and in some cases the very action o* 

 nature suggested the contrary. 



In the case of the Vistula, every attempt to improve the mouth 

 failed; a new outlet was formed and the old channel was converted 

 into a canal which gives the necessary water to Dantzic. At the 

 mouth of the Danube the Jetties gave success, but they were ap- 

 plied to the " Soulina Pass," a comparatively new branch of the 

 river, far removed from the actual delta. The Jetties were carried 

 out into the sea to a point where a current passes from north to 

 south in the Black Sea; this current receives and carries all the 

 alluvium brought down by the river, aud prevents the formation 

 of a bar. The channel has been deepened from nine feet, to six- 

 teen and one-half feet by this means, since the works were con- 

 structed. It is very properly presumed that the encroachment of 

 the whole delta will have the effect of crowding the current farther 

 into the sea, and finally a bar will form as heretofore. 



The improvement of the mouth of the "Adour " was accomplished 

 by means of Jetties, but this river differs very materially from 

 what we consider " working-rivers." The difficulty in this case 

 was, that the obstructions cast up by the Atlantic forced the river 

 in a direction parallel to the shore until its banks were no longer 

 able to contain it; at such times the river would break out and 

 form a new mouth. The mouth below " Baj'onne" was improved 



