The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1876-04-03
THE INTEROCEANIC SHIP CANAL.

COMMANDER LuLL's VIEWS ON THE UNION OF
THE TWO ocEANs-A CANAL WITHOUT LOCKS
NEUTRALITY-SUSPICIOUS. or THE MICA
RAGUA LINE ABOVE THE OTHER ROUTES.
WASHINGTON. March 81. 1874
To THE EDITOR HERALD:-
In your issue OF the 9th inst there appears CON-
municaton giving what purpor to be scientific facts In
regard TO the possible result OF opening ship canal
through the American sthmus from the Caribbean Sea
TO the Pacific Ocean.
The writer goes to describe the climatic effects in
various OF the world Of the oceanic circulation
II now exists. and TO show what stupcndous changes
would IL the Gulf Stream diverted into the
Pacific Admitting all that the writer Gays on these
subjects It only remains for me to show whether or
not probable possible that the Gulf Stream will
DO diverted by tho construction OF an oceanic ship
canal AS your paper has taken interest in this
subject than any other in the country you will no
doubt b. willing 70 give space in your columns for
this purpose.
Your correspondent assumes in opposition to all tho
reports which have been made upon the subject that
thorough cut upon tho level will finally adopted
instead OF resorting to locks This will answer fur
Their on, first showing that thorough cut would
have no effect whatever upon the ocean currents II
your correspondent correct in regard 10 tho
would be TO establish current from the Pacific to the
Caribbean Sea- no makes the level Of the
$50 feet higher than that or the latter. The truth Is
however, that the lovcls OF the two
acty the same, has been repeatedly proved within
tho last twenty-five years Two lines OF levels have
boon run from sea 10 sea under my own direction
whi.o commanding expeditions employed in surveying
intcroccanc canal routes-the first through Nicaragua
in 1872 and the second the Isthmus OF Panama
1875, with the result In each above
given Tho old idea OF a difference Of level
was no doubt duo to faulty work. II has
been corrected however, since the surveys mado for
tho construction OF the Panama Railroad, and your
correspondent should be aware or the fact The line
nearly practicable for thorough cut is between
Aspnwall and Panama. At tho former place the cx-
remc rise and fail OF the tide is less than loot At
the latter owing to the conformation Of the Bay OF
Panama there Is extreme rise and fall of twenty
feet There are, consequently, two periods during
each lunar day when tat spring tides the water level
al Panama about feet higher than that at Aspin
wall, and periods when II Is ten ect lower or, to
state the case little differently the water half
Hood TO halt ebb, period OF about six hours, will DO
higher a. Panama than at Aspinwa'i, with an average
difference OF level OF i've feet during spring tides and
Tor the succeeding six hours-viz from half tide dur
ing the ebb TO half tide at tho following Hood the DIFF
will DO exactly the same the other way The
distance between the places by tho proposed line
OF the canal Is iOrty-tw0 miles, II the waters
would be an average slope during the six hours
difference OF lcvel, OF one and half inches TO the
Caribbean the Pacific there must be established dur
ing the six hours current OF seven miles per hour
otherwise It will be drawn back before II accompllshes
the transit According to Trautwiue's formula the
above mentioned slope Tor a canal with the
proposed will give mean velocity OF little over
one aud miles per hour In practice when there
is a fuctuatng water level zach end OF
thorough cut tide lock is inerposed, or more than
one If the differences OF level arc very great by which
tho In nal Ia uanu
aud vessels locked either or down rs the case
may require III thorough cut were adopted upon the
Panama two tide locks the Pacific sidc would
be required On the Atlantic side the huctua
ton OF the tides is too small to DO source
been said that no current would be- caused
by the difference OF level OF the seas. Let us next
see whether tho equatorial current would have any
that be the idea Of your correspondent though he
hasn't very clearly stated tho iact There is tora
current eddy Of tho equatorial wlch extends along
the whole Central America aud Of the sthnus
as far Cape San Bias 1t IL about twelve miles
WIDE flows u direction generally opposite to that
Of tho equatorial current though following locally the
tren6of the coast cutting across from point 20 point
It's velocity IS from one 10 TWO miles per nour. IN
there current ut ALL Tho ttoral current Is well
known TO all navigators who frequent the Caribbean
from IL Is clear that tho force Of
the equatorial does not reach or impinge upon the
coast ut all
point that thorough cut or canal without locks IS
practicable In point fact It Is neither practicable
desirable for reasons which l shall proceed 10
give.
A CANAL WITHOUT LOCKS IxrRAcrIcABLR.
As have already said thorough cut Is moro
nearly practicable through the lsthmus OF Panama
than any other line. But even that line there
insupcrabc obstacles FIRST, In tho magnitude or
tho work, which would make II cost over thousand
million Of dollars and second from the fact that the
canal would become the ultimate drainage Of all tho
immediate territory The highest point crossed by
this line 2y3 above the level Of either
IL is estimated that the excavation would be IN Garth
for depth OF twenty iect thence IN rock With tho
ell. fptn hank unAa
half To earth and one halt TO one rock, the
section OF the excavation would be at that point
39 feet Deep 4j9 feet wide al the top and ~ feet WIDE
ut bottom. THIS illustration ought 10 DO enough
TO show what an enormous undertaking IL would be.
In the plan actually proposed Tor opening canal
through the istLmus (sec report OF Panama Survey,
appendix to report 0 the Secretary Of the Navy 1870
level OF l23 feet given to the canal Tor the
twotod purpose OF diminishing the excavation aud of
securing drainage for the surplus waters. AT the
lowest stage during exceptionally dry season. while
the survey progress the Chagres River, from
which It Is proposed the supply Tor tho
canal found discharge quantity largely IN
cess OF tho maximum possible demand Like all trop-
cal streams the Chagres subject to sudden and
lent eshets its surface often rising during the rainy
thirty i've and forty icct Il may be imagined
would be the effect of receiving stream
into the canal, TO say nothing OF the numerous
Others whose valleys. like that OF the Chagres are
crossed by the line, necessarily owing the
location Of the only available harbors. BY the pro-
posed plan the canal will tho Chagrcs by via
duct under which arc provided Twelve culvsrts with
during ircshets To supply the canal with water tho
Chagrcs Is tapped ten miles above the point Of
ing and feeder aQueduct leads thence to the canal
Side and cuverts provided the escape OF
the OF such other crossed II tho
canal opened ut the level all these streams
would have to be received into II. else chan
ncs reaching TO the sea should be constructed for
them, involving n cost almost equal TO that Of tho
canal ITSELF This, TO say nothing OF innumcrablo
springs which soil so saturated with the aal rain
ial must supply, shows the immense volume Of water
TO be provided for.
THE NICARAGUA LINE THE MOST FEASIBLE
For canal with locks the line through Nicaragua Is
for many superior TO all others. Here with
level l07 feet above the level OF tho sea-
thirty i've miles wide. The surface OF the lake viii