The New York herald., 1879-12-10

Tuyra-Tupisa route. which by his report sup
posed equal. or nearly so. to any that had been de-
veloped Through our surveys. This line seemed -
me hopeless from the existence of the grayest tiih
culties some of which l mentioned IN nay paper OF
November last Ii seems from what l shall pres
emily quote that Lieutenant Wyse had the trankDess
TO Inform the society for which he acting that
in his view ship canal across that region was ni
possible He did present il at all in the congress-
but took up the Panama route on Whatever ih-
formation he had and developed 1t Tor d SNIP
canal Hreau which certainly was step
in the right direction. 1t may be said without
dispute that for canal at the ocean ievel tne nno
from Panama TO Aspinwal is far preferable 10 any
other The possibility OF it must be considered
simply in commercial sense, as canal, wherever
made must have that condition. The follow
inc aay' Nav 20 civil Engineer Menocal was
invited to explain the plans ana S estin,a.e5
of the Panama route , on, Was MawssSaw saaaested
allowing him to proceed. and making questlons
afterward. -,
beran the survey OF the Panama route there was no
prooccupation to what height above the sea; II
any would be selected as the summit ievel. ihey
foind AT Matachin that the floods of the river passed
some iiye or six the railroad track. and that
nj low water the surface of the stream was 1orty-two
feet above the level In considering the ques-
tion it became apparent that II the ocean level were
adopted an excavation would be necessary. making
the normal surface OF the proposed canal forty-two
feet below the present low water in the river which
would then make small cascade and i'll periods OF
floods would DO transformed into a cataract OF
lGl 900 cubic per second, OF height of nearly
seventy eight feet the decrease being due to the
measure of the velocity of the water approached
te precipce and the head of water above the
ocean level after falling, which would give cor
responding velocity on its course to the sea- was
apparent that either this great volume OF water must
be received into the canal from an elevation which
would make the effect destructive or that 1t would
be necessary lock SO as to permit the moods TO
pass beneath the aqueduc thus bringing the SURFACE
level of the it to an elevation OF ia feet
above the This was found to entail the con-
struction of feeder with its adjuncts, at cost Of
S9,942, 127. with either doubtful or scant water
supply during portion OF the seasons Oh unusual
On concluding Mr.. M.nocal stated his willingness
to answer questions, without eliclting any.
On the 2lst another general session was held. Sir
John Hawkshaw gave his opinion on the Panama
route as follows:-
..With regard to the question whether the canal
should be constructed with or without locks, the
following points occur to me:-
"If the canal is to be without locks its normal
face level would be that Of the and its bottom
level, say eight metres lower.
''This being the case. the canal would receive and
IL traversed
..Therefore it would be necessary to ascertain the
volume of water that would drain into the canal be-
1t would be possible even to determine the Sec
tional area of the canal.
.It tho canal less surface fall than the river.
as would have it must have larger sectional area
to discharge the same volume of water.
''The average section of the river in a flood at
Manei vas ascertained by Mr.. Reclus to be 1,3lO
square metres This would require canal, fit were
eight metres deep. to be lGO metres wide.
'.rhe waters OF the Chagres would have tendency
to dow toward the Pacific, that is. through the
ne the distance is less and the fall greater than
to the Atlantic.
if has for both the river and canal would
be small. Mr.. Menocal's estimate OF the volume
of the Chagres in time OF flood would much more
ton OF the tunnel is only half that of the river In
time of flood, given by Mr.. Keclus.
During the construction OF canal at the sea
level difficulties would arise in providing for the
drainage which would affect both time Of execution
and to extent that could hardly be ascer-
tanned III advance.
'.If from such considerations the foregoing, it
should be concluded that tho canal should be so
constructed retain the rivers for natural drain
age then recourse will have to be had to locks.
.'In that event there can be no difficulty, in my
opinion in carrying on the traffic with locks prop
erly constructed. provided there is an ample water
supply, which would be a sine qua non"
Dwelling upon the axioms heretofore acknowl-
edged by able engineers-to avoid surface drainage
and to have abundant water supply--after read
ing his opinion he remarked that residence Of two
or more years i'll intertropical America had given
him knowledge of how these showers behave, with
out which he might think differently. In conver-
saon with him before lert Paris after two days
attendance at the Congress. he expressed the opn-
ion that the canal could not be excavated ncedu.
and ii it were that 1t would be filled up with trees
and silt.
A pamphlet by NJ. dAvezac. chief engineer OF the
SueZ Canal. compares that canal with the various
routes proposed across this continent. He quotes
at length from my last paper read before this society
showing the marked contrast Of physical conditions,
the region of the Suez Canal having mean annual
rainfall of less than inches while the region Of
the Panama Canal has a rainfall Of l24 inches. His
deduction is that surface drainage falling into canal
has securing effect which is beneficial. whlic the
abrasion of the banks OF u canal il far moro do
structve.
Were it not too great tax your patience.
would point out the allacy of such argument. 1t
is assumed that when u river like the Chagres IL
dredged it will change its regimen. This deduction
il necessary to supposition that canal niredu at
Panama is possible. On the afternoon Of the 10Th
the Technical Commission was divided. one part to
report upon the practcabity OF locks as presented
the Nicaragua route. the other to consider the
question of making tunnels for navigation. There
was confusion and violent action, was informed,
the part OF Lieutenant Wyse. growing out OF his
opposition to Mr.. Menocal being put the sub
GO IN MCnOcal
asked to be excused
The report as to locks was that they could be made
to serve their purpose. The calculations for o
tunnel made for construction dry founda-
ton; it stated there were elements Of calcu
lation for building tunnel below the sea level, as
the plans demanded.
During the sittings OF tho Congress. 1 found
myself frequently obliged to dissent from the prop
ositions OF Commander selfridgc. United States
Navy, who strangely enough was found in the Con-
ess haa Seas ha
engaged during the seasons OF 1870. 1871 and
1873 in examining the coast lying south and east OF
the Panama route at San Bias, Caledonia Bay, the
streams flowing from the hanks Of the mountains,
adjacent the Bay of san Miguel and Of the counter
slopes falling into the Atlantic, also in making
examination OF the Atrato-Nappi route for o ship
canal which will be found in his report to the Secre
tary OF the Navy of June II. 1879
/ refer the curious reader to pages from &C to 20
inclusive and to map g. illustrative Of the Atrato
Napip route as developed by Commander Selfridge.
Nobody reading this report and referring to the
drawings would suppose for an instant that
the greater part OF It was pnrely
Atrato and Doguado never having been passed over
by Commander Selfridge or any of his party. 1t is
delineatcd inclined plane. locks located and
sections of elevations given in figures! Between
this iancful presentation and the profiles made by
Lieutenant Collins. United states Navy. there is
very wide difference. quote from page Of my re-
port
Commander Selfridge then said that the remarks
made by Sir John Hawkshaw in relation to the
Chagres River were not applicable to the Atrato-
Napp route. and endcavored to enter into further
discussion of its merits. stated that would sug-
ges the advantage of discussing the carefully
pared plans OF Lieutenant Collins along the lines OF
actual location which were the best that could be
found in months of labor instead of lines drawn ut
will by Commander Seltridgc. involving uncer-
tainty of execution and entire absence of ele-
nents of calculation. every engineer would recog-
nize.
This was one of several occasions that had to
suggest the advantage OF discussing facts instead OF
indurr in fancies calculated to deceive the credu
ious and unwary, and absolutely waste of time IN
discussing
rhe proceedings Of the general Congress on the
23d and in the Technical Commission on the 10th.
are so significant that shall append them without