New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1858-09-20


begin to restore the old pine-wood garments TO the
p!updered mountain sides VIII bear too hard upon
us to be postponed for the private advantage OF
postmasters, customh house clerks and members OF
Congress.
n. Dausse treats his subject under two heads:
The least possible disturbance of the sources OF
rivers. end The lowest possible leveling Of their
beds. These find equivalent expressions IN the
cm,nt.rclearipg or rewoodng Of the nil country,
| and in the construction Of lakes or reservoirs.
Fverv traveller in the Alps and Pyrenees has no.
ticed the chains Of lakes which make ~ great
beauty in the scene; and how the lower ones
clear and the upper ones muddy, and how above
the uppermost are fat plains which have once been
lakes, filled up with glacial mud. A range Of re-
,eryoirs upon the heads Of our Western rivers
would cut of the very genesis Of their sandbanks,
az well az Of their occasional periodical fresbets.
Add to these the dubious covering of forest, I'M
derbrrsh and prairie sod, ready TO soak up every
drop of rain that falls and turn il gently downward
through the rocks, and jealousy retaining al the
mold and disnteg grated surface Of the earth in the
embraces Of their myriad roots, and We have pic.
ture of eternal rivers with banks and beds eter.
nally at rest.
NJ. Dausse says that natural lakes are rare in
France. They are so in most countries, and in
all billy countries. But it is just in billy coun-
tries that the conditions for artificial reservoirs
abound-n ridges, with narrow gorges or ravines,
in front Of branching valleys. Tie higher the
barriers thrown these defes the greater the
volume Of waters contained behind them, tho
safer becomes the river bed below; but the more
carefully and costly must they be constructed for
the more terrible will be their accidental rupture.
When the sixty-foot dam on the Lehigh in the
rayine of the Pokono Mountain, broke, its solid
wave swept every bridge and dam below il, with
canal banks, locks, mills and villages, away in
| indscriminate ruin 10 its mouth. And when, fifty
years ago. the high mill.dam on the COdOrus broke
away similar wave followed the windings of the
stream for dozen miles; and although there was
time for the miller's to saddle his horse and
gallOp across to York to warn the village folks, yet,
| while they talked over the event and laughed at
the danger, il approached with breastng Ike the
Bore of the Ganges, aud swept of half their
property.
The rewoOding Of naked soils is not so important
| in the New as in the Old World yet, nor will it
ever be on the eastern side Of the continent il
is fast becoming TO the inhabitants Of the Great
Valley. But if every year a single affluent of a
destructive river basin were rewoOded, the change
would soon be apparent, especially since trees but
three years old have marked efficacy. Here it is
not national wealth or science much as national
perseverance that is wanted, and that we know to
be a rarest virtue.
The embankment or leveeing Of rivers has not
yet become science, but is in its rude state of
local chance construction. When the fall Of river
exceeds eight feet to the mile, its levees should be
continuous and doubles that is one line of bank
outside behind tho othor, ooch side. for the
strength of the food and the weakness Of the bar
rier increase together when single levee is used,
which ia an irrational arrangement. And yet this
is the very arrangement hitherto universally adopt
ed. This is an important point, to which we call
the attention Of all Western men and Civil Engi-
neers The first bank should be low, to meet the
ordinary stage Of water. Let every freshet over
ride this quietly it would at first, and spend ts
volume, and of course its strength, over certain
| space behind, and then find second and conse-
quently much stronger barrier, which it could
never break. And then, where ever this interme-
date and oyernowed country is cultivated, instead
Of attempting to protect il against overflow, a vain
attempt and at the same time robbng il of its nat
ura right TO the enriching deposit of the overflow
| let surer way be taken. Let strong transverse
dykes be projected across it, at proper intervals
not to keep out the water but to stop the current
| and protect the soil while il is thus submerged.
| M. Dausse shows also the best form of bank to
be the normal gently slopng tslus of natural river
shore deposit and not the abrupt slope of artificial
masonry. It's, however, not by any means always
| that this form can be obtained as for instance
where river sweeps round sharp bend; but even
there some approximation can be made to If. The
disasters Of the present year, and of late years. III
Louisiana, were distinctly prophesied by an able
United States engineer while experimenting the
construction of the public works in that city
years ago, at the time when so many bends OF the
Mississippi were cut through To shorten its channel
for the convenience of commerce, and, a. it was
alleged, to add security TO the delta against mum
dations by Strengthening the river and allowing to
out its bed by increasing its fall. This gen.
| tlemsn was wise enough 10 see and bold enough 10
say that these awkward and tedious horseshoe
bends were so much natural reservoir to take and
hold the surplus Of the annual flow, and that to cut
them off was not only an unnatural, but suicidal
policy, the consequences of which have at length
been recognized and amented by many who
secuted his theory silly dream.
The history of Holland and of Lombsrdy i
history of single dykes and terrible disasters The