The mirror. (Stillwater, Minn.) 1894-1925, 1920-04-29
THE PANAMA CANAL TODAY
The Construction and Operation Great Waterway
tween the Atlantic and the Pacific
T. Bernod Walkers cAmaan

ton and lighting of the locks and the gen
eral plant throughout the full length of the
Canal, which, it should be said, extends for
a total distance, from deep water to deep
water, of about 40 miles.
The Gatun dam consists of two mas
sive rock fills, with vast central core of
mud and clay which was pumped in hydrau-
Ideally and allowed to settle and solidify. 1t
has proved to be perfectly watertight, thus
allaying the many fears which were expressed
as to the possibility of damming the Chagres
River and holding back an artificial lake of
the great size of Gatun. The difference of
elevation of IS feet between sea level and
Gatun Lake is overcome by flight of three
pairs of locks. Each lock is thousand feet
in length and 10 feet in width. When the
ship comes to rest alongside of the central
pier, which is 1,000-foot extension of the
middle wall of the locks, it is taken in charge
by electric towing locomotives two or three
on each side, according to the size of the yes
sci. The ship is not allowed to use its own
power, but is towed into the locks and taken
from lock to lock by the electric towing To-
comotives. On emerging from the upper
lock, the ship passes into Gatun Lake and
proceeds under its own power at speeds of
from ten to fifteen knots, according to the
depth of the channel which is being dredged
in the bottom of the Lake. The ship steams
through the Lake for "a miles until it
reaches the Continental Divide above re-
ferred to. Here the hills begin to close in
on the channel, and for the next eight miles
or so, it passes through deep cut through
the mountains. Here the channel is 800 feet
wide at water level, and at one point, Gold
Hill, the sides of the cutting rise about 500
feet above the bottom of the Canal. Emery
ing from the Gaillard Cut, the ship arrives
at the locks on the Pacific side known as
Pedro Miguel. Here in single flight the
ship is lowered from the elevation of IS feet
of Gatun Lake, to MiraAores locks, where
in two flights it is lowered to sea level. From
MiraAores locks, it passes trough dredged
channel some miles in length, at the end
of which it finds itself in deep water.
The two controlling problems, from the
engineering standpoint, in building the Canal
were the construction of the Gatun dam,
locks and spillway, and the great cutting
through the mountains in Culebra In both
cases the task was complicated by very poor
quality of the material in and on which these
great works had to be carried out The
ground at Gatun was of loose and more
or-less swampy character, and the rock is of a
late geological formation, which, when ex-
posed to the air and to the heavy rains of the
rainy season, rapidly loses its consistency.
Fortunately, fair quality of rock was found
at the base of the hills on the easterly side
of the site of Gatun dam, and through this
the great flight of locks was built. Toward
the center of the axis of the dam was an
other slight hill of rock which was selected
for building the spillway. The stability and
water tightness of the dam is secured by its
enormous width of half mile and the vast
core of impervious clay slit which forms its
center.
The cutting at Culebra was the other
great obstacle, and here the problem was one
of disposal of the spoil or cxcavated material.
The rapidity with which these enormous
masses of material were execavated and taken
away was due to the use of the very best
American execavating machinery, coupled
with skillfully laid out plan of railway
trackage. When the United States purchased
the Canal from the French company they
found that over 100000 cubic yards had
been taken out; but of this only about 3d.
100000 was useful to the enlarged American
canal. The total excavation, dry and wet,
for the Canal as originally planned, was
estimated at about 104, 100000 cubic yards,
in addition to the French excavation. Adj
ditions brought the estimated total to 1872
100000 cubic yards
The great slides which more than once
entirely filled the Canal were due to the fact
that whereas the cross section of the Canal,
as planned, called for side slopes " to 1,
/, it was found that the rock around Cucaracha,
and particularly at Culebra, was of such UNI