line, from the roadstead of Suez to that of Pelusium, the excavations
will only be in light earth, which can be easily removed by hand as far
as the water line, and with dredges down to the bed of the Canal.
The track which we have followed for the Canal was prescribed by the very
nature of the locality, and by the condition that the two Seas were to be
brought into direct communication in the most economical manner.
The line begins at the roadstead of Suez, turns to the east of the
town, making a curve to reach the ancient track, which it leaves to the
west, and follows the channel of the valley until it joins the Bitter
Lakes, which anciently formed the extremity of the gulf of the Red
Sea. It traverses those lakes throughout their length, following their
sinuosities, so as to avoid the inequalities of the ground. On leaving
the lakes, the line crosses the bar of the Serapeum, at its lowest point,
and enters Lake Timsah, leaving the heights of Cheik Ennedek to the east.
The last-mentioned lake is to serve in the formation of an inland port,
in which ships may be revictualled and repaired, while it will be the
point of junction between the Maritime Canal and the Canal communicating
with the Nile.
In traversing this lake, the line forms several curves, in order to avoid
the extensive downs which have encroached upon a part of that region.
On leaving the lake, the line proceeds to the bar of El Guisr, at its
lowest point, and then goes towards Lake Menzaleh, which it follows
directly along its eastern shore as far as Pelusium, and is prolonged
into the sea until it reaches a depth of 7 _m._, 50.
The dimensions of the Canal have been determined by the idea of creating
a grand passage for maritime navigation, open to steam and sailing
vessels of considerable burthen. The Caledonian Canal is the only known
analogous work. This Canal, however, is but 37 _m._ broad at the water
line, and but 6 _m._, 10 deep. The locks, to the number of 23, have been
enlarged so as to admit forty-four gun frigates; they are 52 _m._, 40 in
length between the gates, 13 _met._ in breadth, and have a depth of water
of 6 _m._, 10.
For cutting through the Isthmus of Panama by a maritime canal, as
projected by Mr. Garella, it was proposed that the width of the canal, at
the water line, should be 44 _met._, and the depth of water 7 _met._
Prince Louis Napoleon, who, in 1846, published a remarkable work,
inserted in the _Revue Britannique_, under the title of _Canal de
Nicaragua_, adopted the same dimensions as Mr. Garella, in the project
which he proposed to execute for establishing the communication between
the Atlantic and Pacific Oceans.
We have assumed on considerations hereinafter to be explained, that
paddle and screw frigates as well as vessels of 1000 to 1500 tons, ought
to be able to traverse the Canal in order to satisfy to the fullest
extent the demands of navigation. We have therefore fixed the width of
the Canal at the water line at 100 _met._; its _minimum_ draught of water
at 6 _m._, 50, below low water in the Mediterranean. The locks, two in
number, are to be 100 _met._ long, 21 _met._ wide, with a _minimum_
depth of water of 6 _m._, 50. These works will be established at the
two extremities of the Canal, immediately before the dykes forming the
channel which on each side unites the Canal with the two Seas. These two
locks will form part of a sluiced barrage, and thus convert the whole
Canal into one immense dam, receiving the waters of the Red Sea during
the highest tides, and storing them up successively in order to raise
the level and create a rush of water in each channel when necessary. The
highest tides of the Red Sea being from 2 _met._ to 2 _m._, 50 above low
water in the Mediterranean, a depth of 9 _met._ of water will be obtained
in the canal at certain times, but a mean super elevation of 1 _m._ may
be depended on, which will usually give a minimum depth of 7 _m._, 50
to 8 _met._ Under these conditions, screw steamers will be enabled to
pass easily along the Canal without the presence of its bed re-acting in
an inconvenient manner on the motion of their screws. We have, however,
calculated the earth-works for three different depths of water, viz. 6
_met._; 6 _m._, 50; and 7 _met._ below low water in the Mediterranean.
If the Company should require a depth of 8 _met._, it would be easy to
obtain it by means of dredges, without stopping the navigation on the
Canal.
The length of each barrage, including the lock, is 100 _met._; and in
order farther to facilitate the entrance of the rising tide into the
Canal, a third barrage has been added at Suez on the site of the existing
channel. This last work will be separated from the first by a platform
raised above the level of high water, so that the two together will unite
the road from Cairo passing by Suez to Mecca. Its length has also been
fixed at 100 _met._
For reasons of economy the width of the Canal has been reduced to 65
_met._ wherever the height of the ground reaches 6 _met._
To prevent the degradation of the banks of the Canal, the slope has been
fixed at two on the base to one in height, and it is proposed to have a
causeway 2 _met._ broad to receive, 1st. A covering of the broken stones
found along the Canal, 2nd. Any earth falling from the higher grounds,
which would otherwise encumber the bed of the Canal. This is only an
imitation of what has proved so successful on the Caledonian Canal.
The width of the towing path has been fixed at 4 _met._, which is quite
sufficient for a maritime canal where steam towing will be so much in use.
Lake Timsah, situated nearly midway between the two Seas, at the entrance
of the _Wady Tomilat_, will form, as we have said, an inland port, to
which both the outward and inward navigation will tend. On its shores
will be established magazines, stables, workshops for repairs, as
well as 1500 _metres_ of quay walls for mooring vessels and embarking
merchandize. For, as the illustrious author of the work on the canal
of Nicaragua well expresses it, the proposed Canal must not be a mere
cutting destined solely to form a passage from one sea to the other for
the produce of Europe, but it must make Egypt a prosperous state by
enabling her to dispose of her interior produce, and a powerful one by
the extent of her commerce.
As for the two entrances, whether from the Red Sea or the Mediterranean,
all that is necessary is, that ships shall be able to approach at all
seasons, and find certain and effectual shelter in bad weather. Now the
roadstead of Suez is sheltered from every wind except the south-east. It
will therefore be sufficient to prolong the eastern jetty to a certain
distance beyond the western to render the shelter complete.
All the vessels which now take their stations in the roadstead ride out
the bad weather very well, and the magazine corvette belonging to the
English Company which has been anchored there for the last two years and
a half has suffered no damage.
Thus, at the Suez extremity, it will be sufficient to establish two
jetties, forming the entrance channel from the Red Sea, and to prolong
them sufficiently far into the roadstead to reach the required depth of
water, in order that vessels entering may have a draught of 7 _m._, 50 to
8 _met._ at low water. The eastern jetty must be 150 _met._ longer than
the western for the reasons we have just given.
At Pelusium, the two jetties, in order to reach the depth of 7 _m._, 50
to 8 _met._ must be at least 6000 _met._ in length; but if it should be
feared that the channel thus formed would not be sufficiently safe for
the approach of vessels, and in order to meet objections, the real value
of which have yet to be tested, we have projected a sheltered roadstead
in front of these jetties by means of a grand mole from 450 to 500 _met._
in length, placed in such a manner as to afford shelter to vessels in bad
weather, and to enable them to enter the channel at their convenience.
At all events no one can doubt that the Canal would be really and
practically navigable for all vessels willing to avail themselves of the
passage. But it will be asked whether jetties extending 6000 _met._ into
the sea do not present great difficulties; whether a trench of 65 _met._
in width, dug 16 _m._, 50 deep, a part of which is under water, is not an
impossibility; and whether, supposing the engineering difficulties to be
surmounted, the results obtained would be in proportion to the expenses
incurred. Doubts have also been started on the navigation of the Red Sea;
finally, several authors have put the question, without however solving
it, whether, even if the Canal were once established, commerce would not
prefer the old way by the Cape as the safest and most advantageous.
These questions we are about to examine: these doubts we shall endeavour
to clear up.
The Gulf of Pelusium is said to be constantly filled with sand or mud
brought down by the Damietta branch of the Nile, and it is objected
that the advanced works to be established on that part of the shore
would only have the effect of increasing the accumulations. We admit
that this portion of the Egyptian shore has been formed by maritime
alluvium brought by the ground swell, as we have already proved at the
commencement of our memorial. We also admit, that the object of the dykes
forming the entrance channel to the Canal, would be to stop the sand thus
brought by the waves, and to accumulate it against the dyke opposed to
the prevailing wind, namely, against the western dyke.
But most of the ports already in existence are open to the same
objections; and if they were sufficient to prevent the construction
of a port, we may safely say that very few of those we are at present
acquainted with would ever have been formed.
According to our idea the essential question is, to know whether, when
once the port is established, it can be maintained without too great an
expense.
Now it appears, that for many ages the sands have ceased to extend the
Pelusiac shore, as is manifest from the well ascertained position of
Pelusium, the ruins of which still remain. Strabo, in his Itinerary, says
that Pelusium is situated at the distance of twenty stadia from the sea.
The French engineers of the expedition have verified this distance, by
measuring 1600 toises, or 3000 _met._ from its remains to the shore.
In 1847, the distance between these two points had not varied, as it is
marked on the plan with the figure 3000 _met._, and at the present day it
is still the same.
In fact, by reading all the accounts of ancient authors, and comparing
them with what actually exists, we arrive at the conclusion that the
shores of the Delta have varied very little in historic times.
The sea sands then have long ceased to accumulate, and the fact may be
explained by assuming that the destruction of the coasts of Morocco,
Algeria, Candia, and other parts,—which destruction, we repeat, alone
furnishes the materials of maritime alluvium, —has abated from some cause
or other. It may also be assumed, that the sands which were formerly
driven by winds and currents into the Gulf of Pelusium, are now cast on
the African coast between Tripoli and Alexandria, and driven inland in
the shape of downs. The fact is, that no new downs are now seen forming
in the Isthmus; those on the seashore being of ancient formation, and
nearly all naturally fixed by vegetation. In conclusion, the extension
of the Pelusiac shore, if such extension there be, is too insignificant
to be taken into consideration.
Now, the direction of the jetties being nearly perpendicular to the
shore, in order to be at right angles with the prevailing wind from W.
N. W., the sand, when the wind is perpendicular to the shore, will be
driven on to the coast and increase its height, as hitherto, no change
being occasioned by the jetties. During the parallel winds, which mostly
prevail, the littoral current, finding an obstacle in the jetties, will
form an eddy to windward, which will increase the force of the current
between the points of the jetties and the mole, so that the sand will be
carried far away; and the probability is, that the bottom will become
deeper.
It is only the oblique winds then, that will carry the sand into the
angles formed by the shore and the windward jetty.
In calm weather, the sea-current which flows along the coast from west
to east has not sufficient force to affect the equilibrium of the
beach. Thus, to sum the matter up, the most that can be feared is the
accumulation of a small quantity of the loose sand in the Gulf at the
angle of the windward jetty. Supposing that even 10,000 _cubic metres
per ann._ should be so deposited, which, according to what we have said,
is an exaggeration, it would take 100 years to advance the beach 400
_metres_, and such an advance would produce no perceptible effect at the
extremities of the jetties.
It may be objected, that by all these movements of the sands, some
portion will necessarily find its way into the channel, and thus, by
degrees, end in obstructing it. To obviate this inconvenience we have at
our disposal dredging machines, and the most powerful means of clearance
derived from a mass of 700,000,000 _cubic metres_ of water, which can be
stored up, above the level of low water in the two Seas, throughout the
whole extent of the Canal, and in the immense reservoir of the Bitter
Lakes.
But are jetties extending 6000 _metres_ into the sea possible? and if
possible, would they not require so much time and such an expenditure of
money as, practically, to cause the undertaking to be given up?
With regard to the possibility, there can be no doubt, for more than
a century ago the Dutch Government constructed a jetty 8000 _met._ in
length in the Bay of the Lion, near the Cape, in water more than sixteen
_met._ deep, in spite of the continued tempestuous weather which succeeds
the settled calms in those latitudes. Such a work, considering the depth
of water, must have required a quantity of materials at least four times
as great as that required for the two jetties and the mole at Pelusium.
It was undertaken by a nation not over rich, at a time when steam was
unknown, and before the invention of machinery, which saves so much time,
expense and labour. There can be no doubt then, that if the cutting of
the Isthmus is admitted to be advantageous, it will be easy to overcome
all difficulties.
With regard to the method of constructing these works, opinions are
no less divided. Some engineers, grounding their opinions on ancient
constructions, recommend that the moles should be formed of immense
blocks of stone of thirty to forty _cubic metres_. Others are of opinion
that the only means of preserving the roads from the accumulation of
sand, is to construct the moles and dykes of open masonry. There are also
some in favour of walls in hydraulic masonry with vertical facings. But,
our own opinion is, that in so important an enterprise, every theoretical
hypothesis should be discarded, and that we ought to be guided solely
by the experience we have acquired in works of an analogous character
already executed. And this is what we have done in adopting the system of
loose stones, as it has been carried out with success: 1. For the dyke at
Cherbourg which is 3768 _met._ long in a depth of water of 14 _m._, 80;
2. For the jetty at Plymouth which is 1364 _met._ long in a depth of 11
_met._ and more; 3. For the dyke in the Bay of Delaware 1200 _met._ long,
with a depth of 14 _met._; 4. For that of the Bay of the Lion 8000 _met._
long, in depths of more than 16 _met._
Objections to this system may, indeed, be raised on account of the
damage sustained at Cherbourg and Plymouth as well as at Algiers, before
the introduction of factitious blocks, but it is necessary to observe,
that both at Cherbourg and Plymouth, the tidal current is exceedingly
strong, its velocity being as much as 4 _met._ per second; that the sea
at these points is very rough, and that there is reason to suppose that
the damage would not have occurred had the blocks been rather larger, and
the interstices well filled up. With regard to the roadstead at Algiers,
it is, as is well known, constantly beaten over by heavy seas, no other
point in the Mediterranean presenting such difficult conditions. We have
in favour of our system most of the moles erected in the various ports
of the Mediterranean, Genoa, Cannes, Barcelona, Valencia, Cadiz, &c. &c.,
all of which are constructed of natural blocks, the largest not exceeding
2 _m._, 50 cube, and which are nevertheless established at considerable
depths of water. Finally, we have on our side the opinions of the most
distinguished English engineers; opinions which have prevailed in
Parliament, and in accordance with which, all the moles in the harbours
of refuge in course of construction are being made, according to the
system of natural blocks sunk into the sea, at certain slopes.
The bottom of the beach, descending by a very gentle inclination, will,
moreover, have the effect of abating the waves, and diminishing their
action against the jetties. This is a well ascertained fact, and one
which may, indeed, be easily conceived; for, supposing that the bottom of
the sea, from a depth below the limit of the motion of the waves, rises
by an extremely gentle slope, until it meets that limit; this meeting
taking place at a very small angle, the bottom will be almost insensibly
substituted for the limit of motion.
At the point of this meeting the undulating motion is _nil_, it is very
feeble at the adjacent points, and easily abated by the resistance and
friction which the molecules experience against the bottom. The abatement
will thus extend vertically up to the surface, and the waves will then
gradually diminish in volume as they approach the shore.
We have, therefore, adopted the system of loose stones for the jetties
and for the mole, with but slight modifications suggested by our own
experience, modifications which consist in making the jetty-heads in
hydraulic masonry to a certain height, as well as the interior surface of
the windward jetty, which is to serve for the towing of vessels.
What we have said of the gulf of Pelusium we may repeat, still more
forcibly, with regard to the roadstead of Suez. The sands have long
ceased to accumulate in any perceptible manner. And if maritime alluvium
is still brought up by the ground swell and the current, it is driven by
the west and south-west winds on to the eastern shore, without reaching
the extremity of the gulf. In fact, the plan of the roadstead was taken
in 1799, and the soundings of the channel are marked, as well as the
shape of the sandbank, which forms a kind of bar at its extremity towards
the roadstead. In 1847, the plan was taken again with the same soundings,
and it is impossible to find the least difference between the two
results, which also agree with those given by Commander Moresby, in his
excellent chart of the Red Sea.
There is, then, nothing to fear on that side, either from the sand or the
violence of the sea. The jetties will be of the simplest construction,
and as the materials are, as it were, at hand, their erection will
present no difficulty.
With regard to the excavation of the Canal to a depth of 6 _m._, 50 below
low water in the Mediterranean, in a very porous soil, the task, at first
sight, presents what appear to be considerable difficulties. We cannot,
indeed, hope to accomplish the whole of the excavation in the dry, or by
pumping, on account of the nature of the ground. It will be necessary,
then, for all that portion below water, to have recourse to dredging;
and, as the quantity of earth to be removed by this means is 57,205,342
_cubic metres_, at first sight it is difficult to conceive how the work
is to be accomplished. But, upon examining the matter more closely,
nothing is found to frighten the most timorous. In fact, a single steam
dredging machine, of twenty horse power, such as those which have been
employed on the Nile, working night and day, can, in twenty-four hours,
raise 1000 _cubic metres_ of sand, from a depth of seven _metres_.
According to this calculation, and supposing the year to consist of only
270 working days, it would take forty dredging machines five years to
complete the labour; but if, instead of such small machines, dredges of
thirty to thirty-five horse power were adopted, it would be easy to raise
1500 _cubic metres per diem_, and the dredging would be more economical.
The quantity of earth to be raised by manual labour amounts to 17,473,790
_cubic metres_, and the deepest cutting does not exceed 10 _metres_ above
the water. This is a small matter when compared with the earth-works
performed in many canal and railway undertakings, and even with those
accomplished before the present century; such, for example, as the one
mentioned by Michel Chevalier, in his investigations concerning the
maritime canal of the Isthmus of Panama (_Recherches sur la Canalisation
maritime de l’Isthme de Panama_).
“It required,” says he, “the treasure which the Viceroys of Mexico had
at their disposal to undertake the cutting at Huehuetoca, the total
length of which is 29,585 _met._, with a depth of from 45 to 60 _met._,
for a length of 800 _met._, and from 30 to 50 _met._ for 3500 _met._ The
expense was 31,000,000.”
Farther on, he adds:—
“Nowadays, however, in a case of necessity, by displaying the improved
appliances at the command of engineering art, it would be possible to
effect cuttings of great depth, and to remove large quantities of earth
at no extraordinary expense. On the Arles canal, at Bouc, for instance,
the plateau of the Lecque was cut through by a trench 2100 _met._ in
length, by 40 to 50 _met._ in depth, at the culminating point. The
expense was under 4,000,000, and yet the cutting was performed by the old
method. In cuttings of magnitude, the soil is now broken by instruments
of enormous power, and the earth is removed by means of railways and
locomotives. All that has to be done by manual labour is to collect the
loose earth and load the waggons. For so important an object as the
uniting of two seas, even the impossible might be attempted.”
Supposing each labourer to do 1 _m._, 50, on an average, _per diem_,
it would only require 8000 labourers for five years to complete the
earth-works; and not a year passes without a levy of between 30 and
40,000 men being commanded by the Viceroy, in several provinces at once,
for the service of the canals alone.
As soon as the project of a ship canal across the Isthmus of Suez is
ascertained to be useful and advantageous, no difficulties of execution,
however great they may be (and we have proved them trifling), will be
considered obstacles to its being carried out.
It would appear at first sight superfluous to demonstrate the utility
of such an undertaking, for what especially strikes the imagination, is
the magnitude of the results promised by the Canal, and the reiterated
efforts made at several epochs, even in times of ignorance, to open this
communication between the two Seas.
But since the publication of M. Lepère’s memorial, so many objections
have been brought forward and so many doubts raised, that public opinion
is undecided, and it becomes necessary to re-establish the question in
all its integrity. We will therefore examine the principal objections
raised against the direct communication between the two Seas.
It has been said that the navigation of the Red Sea is so dangerous,
and that the monsoons cause such delays, that even if the Canal were
established and freely traversed by ships, commerce would not follow that
route, which would in fact, from these peculiar circumstances, be the
longest and most perilous.