A. Sea-level section of canal, seven miles long, from Atlantic Ocean to
Gatun Locks, where by a series of three locks vessels are raised to
Gatun Lake, eighty-five feet above sea level. B. Small area of land
dredged away as soon as Gatun Locks were completed. C. Electric towing
motor, four of which tow each vessel entirely through the locks. They
run on cog rail along the lock walls. D. Lock gate under construction.
E. Floor of first lock from Atlantic side. Note holes in floor for
admitting the water. F. Lock for vessels coming from Pacific side. G.
Base on which concrete posts were erected for electric lights. A row of
lights on all sides of the locks making operation at night as safe as
day. H. Incline from locks of different levels up and down which the
towing motors run on cog rails.]
[Illustration: GAILLARD CUT LOOKING SOUTH FROM BEND IN EAST BANK NEAR
GAMBOA
The train and shovel are standing on the bottom of the cut. The water in
the drainage canal is about ten feet below the bottom of the canal, or
at elevation +30.]
[Illustration: A CYLINDRICAL VALVE MACHINE, MOTOR AND LIMIT SWITCH
This machine is one of many which are used to regulate the flow of water
to the locks. All valves are controlled from a central operating station
on each of the three sets of locks. The limit switch automatically shuts
off the power and stops the motor when the valve is entirely open or
shut.]
[Illustration: CUCARACHA SLIDE ATTACKED BY A FLEET OF DREDGES
This great slide was the source of much trouble to the engineers. At one
time it entirely blocked the canal at the narrow point shown in this
photograph, but the seven dredges of the ladder, suction and dipper
type, made short work of cutting the 150-foot channel shown here, and
then proceeded with the work of entirely clearing the cut. The view
looks north from the slide past Gold and Contractor’s Hills.
_Copyright by Underwood & Underwood, N. Y._]
[Illustration: STEAM SHOVEL BURIED UNDER FALL OF ROCK]
[Illustration: THE GREAT GAILLARD CUT
At this point the canal is cut through what is practically a mountain
range. The material excavated consisted largely of rock and formed one
of the hugest engineering problems in the world’s history. The cut is
nine miles long, 300 feet wide, 272 feet greatest depth and required the
excavation of 100,000,000 cubic yards of material.]
Gatun Lake, impounded by Gatun Dam, has an area of 164 square miles when
its surface is at the normal elevation of eighty-five feet above sea
level, and is the largest artificially-formed lake in the world. The
area of the water-shed tributary to the lake is 1,320 square miles.
During the rainy season, from April to the latter part of December, the
run-off from this basin exceeds considerably the consumption of water,
and the surplus is discharged through the spillway of Gatun Dam. Toward
the end of the rainy season the surface of the lake is raised to about
eighty-seven feet above sea level, in order to afford a surplus or
reserve supply to keep the channel full to operating depth during the
dry season, in part of which the consumption and evaporation are in
excess of the supply. It is calculated that when this level has been
attained at the beginning of the dry season the reserve is sufficient to
assure a surface elevation of at least seventy-nine feet at the end of
the dry season in spite of the consumption at the hydroelectric station,
and allowing forty-one passages of vessels through the locks each day
with the use of the full length of the chambers, or fifty-eight lockages
a day when the shorter sections of the chambers are used and cross
filling is employed, which would usually be the case. This is a greater
number of lockages than can be made in one day.
[Illustration: STEAM SHOVEL LOADING ROCK
These great machines, which are able to dig out and load several tons of
material at each operation, made the rapid progress in digging the canal
possible.]
Gigantic Obstacles.
The greatest difficulty encountered in the excavation of the canal was
due to slides and breaks which caused large masses of material to slide
or move into the excavated area, closing off the drainage, upsetting
steam shovels and tearing up the tracks. The greatest slide was at
Cucaracha, and gave trouble when the French first began cutting in 1884.
Though at first confined to a length of 800 feet, the slide extended to
include the entire basin south of Gold Hill, or a length of about 3,000
feet. Some idea of the magnitude of these slides can be obtained from
the fact that during the fiscal year 1910 of 14,921,750 cubic yards that
were removed, 2,649,000 yards, or eighteen per cent, were from slides or
breaks that had previously existed or that had developed during the
year.
[Illustration: ONE OF THE GUARD GATES, GATUN LOCKS, PANAMA CANAL
Each lock is provided with four gates. This shows the method of
construction, the gate being only partially finished.]
[Illustration: GATUN UPPER LOCKS, EAST CHAMBER
The view is looking north from the forebay showing the upper guard gates
and emergency dam.]
The one greatest undertaking of the whole excavation was the Gaillard
Cut. Work had been in progress on this since 1880, and during the French
control over 20,000,000 cubic yards were removed. On May 4, 1904, when
the United States took charge, it was estimated that there was left to
excavate 150,000,000 cubic yards. Some idea of the size of this big cut
may be formed from the fact that this division has within its
jurisdiction over 200 miles of five-foot-gage track laid, about
fifty-five miles of which is within the side slopes of the Gaillard Cut
alone.
Gatun Dam.
The great dam at Gatun is a veritable hill--7,500 feet over all, 2,100
feet wide at the base, 398 feet through at the water surface, and 100
feet wide at the top, which is 115 feet above sea level. The dimensions
of the dam are such as to assure that ample provision is made against
every force which may affect its safety, and while it is made of dirt, a
thing before unheard of, it is of such vast proportions that it is as
strong and firm as the everlasting hills themselves.
Fluctuations in the lake due to floods are controlled by an immense
spillway dam built of concrete. The front of the dam is the arc of a
circle 740 feet long with fourteen openings which, when the gates are
raised to the full height, permit a discharge of 140,000 cubic feet per
second. The water thus discharged passes through a diversion channel in
the old bed of the Chagres River, generating, by an enormous electric
plant, the power necessary for operating the locks.
The locks of the canal are in pairs, so that if any lock is out of
service navigation will not be interrupted, also, when all the locks are
in use the passage of shipping is expedited by using one set of locks
for the ascent and the other for descent. These locks are 110 feet wide
and have usable lengths of 1,000 feet. The system of filling adopted
consists of a culvert in each side wall feeding laterals from which are
openings upward into the lock chamber. The entire lock can be filled or
emptied in fifteen minutes and forty-two seconds when one culvert is
used and seven minutes and fifty-one seconds, using both culverts. It
requires about ten hours for a large ship to make the entire trip
through the canal.
Meeting all Emergencies.
Many extraordinary feats of engineering were accomplished to overcome
the difficulties presented. Special contrivances, wonderful in their
operation, were invented to meet exigencies and emergencies.
The first and greatest problem attempted by the United States was to
make the Canal Zone healthful. This strip of land from ocean to ocean
abounded in disease-breeding swamps and filthy habitations unfit for
human beings. The death-rate was appalling and the labor conditions
terrible. During the first two and a half years, therefore, all energies
were devoted to ridding the Isthmus of disease by sanitation, to
recruiting and organizing a working force and providing for it suitable
houses, hotels, messes, kitchens and an adequate food supply. This work
included clearing lands, draining and filling pools and swamps for the
extermination of the mosquito, the establishment of hospitals for the
care of the sick and injured and the building of suitable quarantine
quarters. Municipal improvements were undertaken in Panama and Colon and
the various settlements in the Canal Zone, such as the construction of
reservoirs, pavements and a system of modern roads. Over 2,000 buildings
were constructed besides the remodeling of 1,500 buildings turned over
by the French company.
[Illustration: LOCK GATE OPERATING MACHINERY
_Photograph, Underwood & Underwood, N. Y._
The great gear wheel, known as a “bull wheel,” is connected with one
leaf of the gate on the right by means of a strut so that revolving the
bull wheel by means of an electric motor through a train of gears
results in opening or closing the gate.]
[Illustration: PANAMA, PAST AND PRESENT
Scene showing the repaving of one of Panama’s old muddy streets with
vitrified brick. Sewers and water pipes were laid throughout the city,
resulting in a great reduction of disease.]
It was only after all this preliminary sanitation was accomplished that
the real work of digging the canal could go forward with any hope of
success. These hygienic conditions had the result of making the Canal
Zone one of the most healthful spots in the world, and work on the canal
became so popular that it was no longer necessary to enlist recruits
from the West Indies, the good pay, fair treatment and excellent living
conditions bringing thousands of laborers from Spain and Italy. The
greatest number employed at any one time was 45,000, of which 5,000 were
American.
A Battle Won.
The completion of this herculean task marked an epoch in the history of
the world. A gigantic battle against floods and torrents, pestilence and
swamps, tropical rivers, jungles and rock-ribbed mountains had been
fought--and won! Well worthy a place in the halls of immortal fame are
the names of the thousands of sturdy sons who, with ingenuity, pluck and
perseverance never before equaled, succeeded in making a pathway for the
nations of the world from ocean to ocean.
This great and daring undertaking, which had for its object the opening
up of new trade routes and lines of commerce, annihilating distance and
wiping out the width of two continents between New York and Yokohama and
making the Atlantic seaboard and the Pacific coast close neighbors, is
the climax of man’s achievement and the greatest gift to civilization.
It will help in the consummation of man’s loftiest dreams of world
friendship and world peace.[2] So far, in the use of the canal, over
forty per cent of the vessels which have passed through it have been
engaged in the coastwise trade of the United States--each of them saving
about 7,800 miles on each trip. If their average speed be taken at ten
knots, they have averaged a saving of over a month at sea on each voyage
from coast to coast. Where formerly the round trip of a ten-knot vessel
required about fifty-five days’ actual steaming, the time at sea for the
same trip for the same vessel is now reduced to about twenty-two days.
The canal makes San Francisco nearer to Liverpool by 5,666 miles, a
saving of two-fifths of the old journey by Magellan. The distance
between San Francisco and Gibraltar has been reduced from 12,571 miles
to 7,621 miles, a saving of 4,950 miles, or thirty-nine per cent of the
former distance.
From San Francisco to Buenos Aires, via Valparaiso and Magellan, is
approximately 7,610 miles, which is shorter than the route through the
canal, by which the distance is 8,941 miles. To Rio de Janeiro, the
distance via Magellan is 8,609 miles; by the canal 7,885 miles. To
Pernambuco, on the eastern promontory of South America, the distance via
Magellan is 9,748 miles; via the canal 6,746 miles. To Para the
distances via Magellan and via the canal are 10,852 and 5,642 miles,
respectively.
From San Francisco to Freetown, on the west coast of middle Africa, the
distance by the most practicable route, using the Strait of Magellan, is
11,380 miles. Through the canal and by way of the island of Barbados,
the distance is 7,277 miles. The new route is less than two-thirds of
the former.
With reference to the trade between the Atlantic coast of the United
States and the west coast of South America, New York is nearer to
Valparaiso by 3,717 miles by virtue of the canal; to Iquique, one of the
great nitrate ports, by 4,139 miles; and to Guayaquil by 7,405 miles.
From New York to Guayaquil the present distance of 2,765 miles is
approximately twenty-seven per cent of the former distance--10,270
miles.
[Illustration: FORTY TONS OF DYNAMITE DESTROY THE LAST BARRIER BETWEEN
THE OCEANS
The blowing up of Gamboa Dike, the last of the dikes in the Panama
Canal. This dike separated the water in the Gatun locks from Gaillard
Cut. The removal of the dike by a discharge of forty tons of dynamite,
set off by President Wilson, from Washington, was the last stage in the
completion of the great waterway. Dredges were put to work immediately
widening the channel at Cucaracha slide in Gaillard Cut, so that within
a short time the canal was ready for use throughout its entire length.
_Copyright by Underwood & Underwood._]
[Illustration: STEAM SHOVEL AT WORK IN GAILLARD CUT, WITH LARGE ROCK IN
MOUTH OF SHOVEL
The great progress made in digging the Panama Canal was largely due to
the steam shovels.]
As to the Far East, New York is nearer to Yokohama by 3,768 miles than
formerly by way of the Suez Canal, but the latter route is eighteen
miles shorter than the Panama route for vessels plying between New York
and Hongkong. New York is forty-one miles nearer Manila by Panama than
by Suez, and 3,932 miles nearer Sydney by Panama. New York is now, by
virtue of the Panama Canal, nearer than Liverpool to Yokohama by 1,880
miles, and nearer than Liverpool to Sydney by 2,424 miles.
When the ship enters the harbor of either of the terminal ports it is
boarded by officers of the canal who examine its bill of health and
clearance, see that its certificate of canal measurement is properly
made out, and ascertain any of the vessel’s needs in the matters of
fuel, supplies, extra men to handle the lines during the passage of the
locks, etc. These matters are immediately reported to the Captain of the
Port, who gives the necessary orders to insure proper attendance on the
vessel’s needs and directs its start through the canal whenever it is
ready.
In all stages of its transit of the canal the vessel must have on board
a government pilot. There is no charge for pilotage on vessels going
directly through the canal without stopping to discharge cargo or
passengers at the terminal ports. The pilot is on board in an advisory
capacity and is required to confer with the master of the vessel, giving
him the benefit of his knowledge and advice as to the handling of the
vessel in the various reaches, but the master, who is best acquainted
with the peculiarities of his vessel and her ways of answering the helm,
is responsible for the navigation of the vessel, except when she is
passing through the locks.
The handling of a vessel during its transit of the canal is like the
handling of a railway train on its “run.” The course is equipped with
all requisite signals, facilities for mooring, like sidings, and a
system of communication between points along the line, which includes a
special telephone system connecting all the important points of control
in series.
As soon as the vessel starts on its transit of the canal, the Captain of
the Port at the point of entrance telephones its starting to the other
stations along the course. As the vessel arrives and departs from each
of these points, the fact is telephoned along the line, so that there is
exact knowledge at each station all the time of the status of traffic,
and complete co-operation from the several points of control.
The transit of the canal requires about ten hours, of which
approximately three hours are spent in the locks. In the sea-level
channels and Gaillard (formerly “Culebra”) Cut the speed of vessels is
limited to six knots; through Gatun Lake they may make ten, twelve and
fifteen knots, according to the width of the channel. A vessel may clear
from the canal port at which it enters and, after passing through the
last of the locks, put direct to sea without further stop.
The handling of a vessel all through the canal, except in the locks, is
essentially the same as its handling through any charted channel where
observance of signals, ranges and turns is necessary. The canal channel
throughout is very accurately charted, fully equipped with aids to
navigation, and governed by explicit rules with which the pilots, of
course, are thoroughly familiar.
In the locks, the vessel is under the control of the lock-operating
force. As the vessel approaches the locks, the operator in charge at the
control house indicates by an electrically operated signal at the outer
end of the approach wall if the vessel shall enter the locks and, if so,
on which side; or if it shall keep back or moor alongside the approach
wall. If everything is ready for the transit of the locks, the vessel
approaches the center approach wall, which is a pier extending about a
thousand feet from the locks proper, lines are thrown out, and
connections are made with the electric towing locomotives on the
approach wall.
The vessel then moves forward slowly until it is in the entrance
chamber, when lines are thrown out on the other side and connections are
made with towing locomotives on the side wall. Six locomotives are used
for the larger vessels, three on each wall of the lock chamber. Two keep
forward of the vessel, pulling and holding her head to the center of the
chamber; two aft, holding the vessel in check; and two slightly forward
of amidships, which do most of the towing of the vessel through the
chamber. The locomotives are powerful affairs, secured against slipping
by the engagement of cogs with a rack running along the center of the
track, and equipped with a slip drum and towing windlass, which allow
the prompt paying out and taking in of hawser as required. No trouble
has been experienced in maintaining absolute control over the vessels.
The water within the lock chamber proper, beyond the entrance chamber,
is brought to the level of that in the approach, the gates toward the
vessel are opened, the fender chain is lowered, and the locomotives
maneuver the vessel into the chamber and bring it to rest. The gates are
then closed, the water raised or lowered, as the case may be, to the
level of that in the next chamber, the gates at the other end are
opened, and the vessel moved forward. Three such steps are made at
Gatun, two at Miraflores, and one at Pedro Miguel.
When the vessel has passed into the approach chamber at the end of the
locks, the lines from the towing locomotives on the side wall are first
cast off, then those from the locomotives on the approach wall, and the
vessel clears under its own power.
Towing is not ordinarily required in any part of the canal, except in
the locks, for steam or motor vessels. Tug service for sailing ships or
vessels without motive power is at the rate of $15 per hour. If the
channel in the cut has been disturbed by a slide, tugs may be used to
handle vessels past the narrow places, but in such cases there is no
charge for the service to vessels of less than 15,000 gross tonnage.
* * * * *
What is a Geyser?
The famous geyser shown in the illustration is called “Old Faithful”
because of the clock-like regularity of its eruptions. For over twenty
years it has been spouting at average intervals of sixty-five minutes.
Geysers were first observed in Iceland and the name, therefore, comes
from that language, being derived from the word “geysa,” meaning “to
gush” or “rush forth.” That is just what they do.
There are really three different kinds of geysers; one which throws up
hot water, either continually or, like “Old Faithful,” at intervals; one
which simply emits steam and no water and one which is a sort of a
hot-water cistern.
The “Grand Geyser” at Firehole Basin in Yellowstone Park is the most
magnificent natural fountain in the whole world. The “Great Geyser” and
the “New Geyser” are the most remarkable ones in Iceland, where there
are about a hundred altogether. The basin of the former is about seventy
feet in diameter, and at times it throws up a column of hot water to the
height of from eighty to two hundred feet in the air.
The hot-lake district of Auckland, New Zealand, is also famous in
possessing some of the most remarkable geyser scenery in the world. It
was formerly noted for the number of natural terraces containing hot
water pools, and its lakes all filled at intervals by boiling geysers
and hot springs, but the formation of the country was considerably
altered by a disastrous volcanic outbreak in 1886, its beautiful pink
and white terraces being destroyed. It still has, however, a circular
rocky basin, forty feet in diameter, in which a violent geyser is
constantly boiling up to the height of ten to twelve feet, emitting
dense clouds of steam. This is one of the natural wonders of the
southern hemisphere and is much visited by tourists traveling through
New Zealand.
[Illustration: _Photo by Brown Bros._
“OLD FAITHFUL” IN ERUPTION]
What Kind of Dogs are Prairie-Dogs?
Prairie-dogs are not really dogs at all, but a kind of a squirrel called
a marmot. As the visitors to city Zoological Parks already know, these
animals make little mounds of earth, and a great many of these are found
in one locality, which is known as a “dog-town.” It is possible to
travel for days at a time through country which is dotted over with
mounds, every one of which is the home of a pair or more of
prairie-dogs. These mounds are usually about eighteen feet apart, and
consist of about as much earth as would fill a very large wheelbarrow.
This is thrown up by the prairie-dog when he digs out his subterranean
home. His dwelling sometimes has one entrance and sometimes two, and
there are many much-traveled paths between the different hillocks,
showing that they are very neighborly and sociable with one another.
In choosing a town site, they select one which is covered with short,
coarse grass, such as is found especially in fields on high ground and
mountain sides, for it is on this grass and certain roots that the
prairie-dogs feed. On the plains of New Mexico, where for miles you will
not find a drop of water unless you dig down into the earth for a
hundred feet or so, with no rain for several months at a time, there are
many very large “dog-towns,” and it is, therefore, clear that they are
able to live without drinking, obtaining enough moisture for their needs
from a heavy fall of dew.
At about the end of October, when the grass dries up and the ground
becomes frozen hard, so that digging is out of the question, the
prairie-dog creeps into his burrow, blocking up the opening in order to
keep out the cold and make everything snug, and goes to sleep until the
following spring, without having had to lay up a store of food, as some
animals do, to last him through the long, hard winter months. If he
opens up his house again before the end of cold weather, the Indians say
it is a sure sign that warmer days are near at hand.
If one approaches very cautiously so as not to be observed, a large
“dog-town” presents a very curious sight. A happy, animated scene
stretches away as far as the eye can see. Little prairie-dogs are found
everywhere, on the top of their mounds, sitting up like squirrels,
waving their tails from side to side and yelping to each other, until a
most cheerful-sounding concert is produced. If you listen carefully, as
you draw nearer, however, you will notice a different tone in the calls
of the older and more experienced animals, and that is the warning
signal for the whole population to disappear from view into their
burrows. Then, if one hides quietly in the background and waits
patiently for some time, sentinels will mount up to their posts of
observation on top of the mounds and announce that it is safe to come
out of their burrows and play about again, as the danger is past.
What is Spontaneous Combustion?
Spontaneous combustion is the burning of a substance or body by the
internal development of heat without the application of fire.
It not infrequently takes place among heaps of rags, wool and cotton
when sodden with oil; hay and straw when damp or moistened with water;
and coal in the bunkers of vessels.
In the first case, the oil rapidly combines with the oxygen of the air,
this being accompanied by great heat. In the second case, the heat is
produced by a kind of fermentation; and in the third, by the pyrites of
the coal rapidly absorbing and combining with the oxygen of the air.
The term is also applied to the extraordinary phenomenon of the human
body, which has been told of some people, whereby it is reduced to ashes
without the application of fire. It is said to have occurred in the aged
and persons that were fat and hard drinkers, but most chemists reject
the theory and altogether discredit it.