The New York herald., 1875-08-19
The Lesson of the Mississippi Floods.

the Mississippi and its tributaries shows that
very rapid variations of the river levels are
occurring at several points along their re-
spective courses. The regular reports have
shown from day to day the actual progress
OF the inundations by reference to the sew
eral points successively threatened and the
more or less rapid rise or fall of the waters
at these places A noticeable feature of all
these reports is the doubtful expressions,
under the head of probabilities, regarding
the rise or fall of the river levels at GER
must necessarily be based on the uncertain
movements of succession of waves of in
undation created by local rain storms, which
produce the oscillations in the river levels
observable during periods of heavy rain,
such as are now being experienced in the
northern, eastern and southwestern sections
of the Mississippi basin The great length
Of the rivers and the immense area of the
watersheds drained by them create the pos
sibility of extraordinary relative differences
of level as compared with the ordinary
height of the river at several points. Thus
rapid rise may be taking place at Cairo and
New Orleans simultaneously, while the
intervening centre of subsistence pre-
sents itself at Vicksburg. These oscillations
are very rapid on all the Ohio Valley rivers,
and are due to the topography of that water
shed, which is favorable to the speedy dis
charge of heavy rainfall into the natural
lines of river drainage. The regions whence
the destructive foods that are devastating
the lowlands have descended are peculiarly
liable to storm visitations, being within the
zone which lies between the areas of genera
tion of warm and cold currents, and where
these contending pneumatic forces struggle
for the mastery and develop in their meet
ing the atmospheric disturbances that
culminate in the meteoric phenomena of
rain storms, tornadoes and cyclones.
The Mississippi below Cairo has received
all the waters of the recent storms, and
which, being brought down by the tribu-
tary systems, have gathered force and volume
in their descent, and rushed into the main
river with the accumulated energy of the
entire rainfall of an immense area collected
in one body. 1t has been geologically demon
strated that the junction of the Ohio with the
Mississippi marks the northerly limit Of the
area of valley or bottom land subject to intEn-
dation. From this point to the Gulf of Mex
leo stretch the great alluvial plains of 'the
Mississippi bottom" and it is from here that
the levee system must be perfected on either
bank of the great river for their protection
from inundation. The floods that have de-
stroyed so much property along the exposed
or badly defended river fronts are now pour
level at Cairo, Memphis, Vicksburg and New
Orleans are due to local rain storms, which
have q slight effect on the volume of water
in the river, or to the gradual downward
progress of the swollen waters being
checked at certain points and damned back
by the sinuosities of the channel or other
causes.
Never perhaps, in the history of the Mis-
sissippi floods has better opportunity pre-
sented itself for q complete study of the
physics of the river, from which plans may
be devised by which permanent and reli-
able protection can be afforded for the
future. The HERALD has frequently pointed
out the necessity for the adoption Of protec-
tive measures against the frequent and de-
structive inundations that threaten to utterly
impoverish this important section of the
country, and has recommended the work to
the attention of the local governments of the
interested regions as one in which co-opera-
ton would produce the grandest results and
assure the material prosperity of the river
States. Millions of dollars worth of prop
erty is annually destroyed along the line of
the Mississippi and its tributaries which
would be saved if determined united and
we'll directed effort was made to remedy
evils that arise from ignorance, apathy and
jealousy. The United States engineers who
were detailed to examine and report on the
Mississippi levee system and the general
condition Of the river have recommended the
remodelling of the whole plan of dylling out
the waters from Cairo to the Gulf This
work should be commenced at once. Any
errors heretofore made in the location and
construction Of levees should be rectifed, so
that the capacity of the channel will not be
impaired and free flow be permitted to
the food waters from the upper watershed.
Great disasters, such as are now visiting this
fertile region, cause o disturbance in the
trade and financial equilibrium of the whole
country which reacts on every branch of in
dustry, and, although one section may be
temporarily benefited by the prostration of
another in the long run each will have to
bear its share of the cost of building up
again with years Of painful labor what few
well timed efforts might have saved from de-
struction.
The Irish Centennial.
Our Dublin letter recounts with some de-
tail the characteristic scenes of the celebra-