Washington telegraph., 1851-03-05
SukvEYINc THE MlsslssIpp1.-The re-

SURVEYING THE MISSlSSlPPI-1u uo Ae-
port of the Board of Typographical Engi-
neers to the Secretary Of War, on the
subject of the foundations OF the Lower
Mississippi, exhibits in strong light the
vastness of the subject, and the immense
amount Of scientific examination and
labor which are deemed Indispensable in
order to arrive at determination OF the
questions submitted 20 them, OF ascertain
inc the most effectual method, and most
suitable direction, for conveying the sur
plus waters of the Mississippi into the
Gulf After occupying thirteen pages OF
the pamphlet i'll describing places and
the character of the territory to be drain
ed, the Board proposes the details of
operations which will be required.
They require the entire photography
of the delta district. containing from
$4,000 to $4,000 square miles, with all
its bays, inlets, lakes. bayous, swamps,
&C., to ascertain the extent and force OF
the water sheets between the surface of
ordinary high water. as the highest level,
and of low tide in the Gulf, and the
several capacities of these plains for the
sedimentary deposits of the river. One
or more standard lines are to be made,
entirely across the delta district, below
the mouth of Red River, as the basis Of
subordinate surveys, and others between
the Red River and Arkansas: and similar
lines across the district above the mouth
Of the Arkansas, from the upland slopes
on the west side of Black and White
Rivers, across the Mississippi to the base
Of the Yazoo hills, with intersecti1g lines
running north and south. A transverse
section of the river is required few miles
above New Orleans, with all the sub
ordinate sections at the same point, from
the highest to the lowest water marks;
the average velocity Of the currents cor
responding to each of these slopes, must
be determined with the utmost precision,
aud the duration Of each stage be care
fully observed and noted in months, days
and hours, for the space of one year, for
the purpose of determining the aggregate
annual duration of each stage of water,
the amount of water conveyed annually
through the river channel, from New
Orleans to the Gulf, without overfowing
the banks; careful analysis TO be made
and constantly repeated, to ascertain the
i'll the water at each stage OF height and
velocity. A transverse section OF the
river is required near the mouth of the
Red River, to determine the quantity of
water brought down by the river at its
highest stage at that point and lis aver
age velocity, in order to ascertain the
difference in the quantity brought down
there, aud that brought down by the
section at New Orleans, thus to show
what ought to be discharged between
these two points, TO prevent II from over
flowing below. The number, place and
capacities of the outlets necessary ~
carry off this surplus difference, are to be
next determined. Surveys are TO be taken
running ir zigzag lines from shore to
shore of the river, commencing at Helena.
Ark, or perhaps at Cairo, H., and ex-
tending to New Orleans and the Gulf.
These, with necessary DRAWINGS, define
ations, maps, charts, &C., have cut out
a prodigious quantity of work, the end of
which we are unable to orsee.-PIc0yMne.