152 DIFFICULTY OF ESTIMATING [CHAP. XXIX. 



feet water in it, but the channel has grown shallower 

 by two feet. When it is considered that a fleet of 

 the largest men-of-war could sail for a thousand 

 miles into the interior, were it not for the bars thrown 

 across the entrance of each of the mouths or passes, 

 one cannot wonder that efforts should have been 

 made to deepen the main channel artificially. But 

 no human undertaking seems more hopeless ; for, after 

 a great expenditure of money in 1838 and 1839, and 

 the excavation by means of powerful steam dredges 

 of a deep passage, the river filled up the entire cavity 

 with mud during a single flood. 



One of the chief pilots told us, that since 1839, or 

 in six years, he had seen an advance of the prominent 

 mouths of the river of more than a mile. But Linton, 

 the oldest and most experienced of them, admitted 

 that the three passes called the north-east, south-east, 

 and south-west, had in the last twenty-four years 

 only advanced one mile each. Even this fact would 

 furnish no ground for estimating the general rate at 

 which the delta advances, for on each of these narrow 

 strips of land, or river-banks, the sea would make ex 

 tensive inroads whenever the main channel of dis 

 charge is altered and there is a local relaxation of the 

 river s power. Every year, as soon as the flood 

 season is over, the tide enters far up each channel, 

 scouring out mud and sand, and sweeping away 

 many a bar, formed during the period of inundation. 

 Bringier, an experienced surveyor of New Orleans, 

 told me, that on revisiting the mouths of the Missis 

 sippi after an interval of forty years, he was sur 

 prised to observe how stationary their leading features 



