The “Daily News” of January 22nd, 1875, in presenting its readers with a chart of the proposed tunnel, offered also the following sensible and interesting comment on the subject:
“This long-debated project has at length emerged from the region of speculation, and is entering the stage of practical experiment. On this side the Channel a company has been formed to carry out the work, and on the other side the French Minister of Public Works has presented to the Assembly a Bill authorizing a French company to co-operate with the English engineers. The enterprise is one worthy of the nations which have in the present generation joined the two shores of the Atlantic by an electric cable, and cut a ship canal through the Isthmus of Suez, and of the age which has obliterated the old barrier of the Alps. All these gigantic undertakings seemed almost as bold in conception and as difficult of execution as the great work now about to commence. Those twenty miles of sea have long been crossed by telegraph lines; they will soon be bridged, as it were, by splendid steamers; but even our own generation, accustomed as it is to gigantic engineering works, has scarcely regarded the construction of a railway underneath the waves as within the reach of possibility. M. Thomé de Gamond, who first made the suggestion five and thirty years ago, was long regarded as an over-sanguine person, who did not recognize the inevitable limits of human skill and power. A tunnel under twenty miles of stormy sea seemed very much like an engineer’s dream, and it is only within the last few years that it has been regarded as a feasible project. Of its possibility, however, there seems now to be no manner of doubt. It is merely a stream of sea-water, and not a fissure in the earth, which divides us from the Continent. Prince Metternich was right in speaking of it as a ditch. The depth is nowhere greater than one hundred and eighty feet; and so far as careful soundings can ascertain the condition of the soil underneath the water, it consists of a smooth unbroken bed of chalk. The success of the experiment depends on this bed of chalk being continuous and whole. Should any very deep fissure exist, which is extremely improbable, the tunnel may probably not be driven through it. But given, what every indication shows to exist, a homogeneous chalk bed some hundreds of feet in thickness, the driving of a huge bore for twenty miles through it is a mere question of time, money, and organization, and as the engineers have these resources at their command, they are sanguine, and we may even say confident, of success.
Fig. 186.—Section of the Channel Tunnel.
Fig. 187.—View of Dover.
“The method by which it is proposed that the excavation shall be made is in some respects similar to that which was successfully employed in tunnelling the Alps. Mont Cenis was pierced by machinery adapted to the cutting of hard rock; the chalk strata under the Channel are to be bored by an engine, invented by Mr. Dickenson Brunton, which works in the comparatively soft strata like a carpenter’s auger. A beginning will be made simultaneously on both sides of the Channel, and the effort will at first be limited to what we may describe as making a clear hole through from end to end. This small bore, or driftway as it is called, will be some seven or nine feet in diameter. If such a communication can be successfully made, the enlargement will be comparatively easy. Mr. Brunton’s machine is said to cut through the chalk at the rate of a yard an hour. We believe that those which were used in the Mont Cenis Tunnel cut less than a yard a day of the hard rock of the mountain. Two years, therefore, ought to be sufficient to allow the workers from one end to shake hands with those from the other side. The enlargement of the driftway into the completed tunnel would take four years’ more labour and as many millions of money. The millions, however, will easily be raised if the driftway is made, since the victory will be won as soon as the two headways meet under the sea. One of the great difficulties of the work is shared with the Mont Cenis Tunnel, the other is peculiar to the present undertaking. The Alps above the one, and the sea above the other, necessarily prevent the use of shafts. The work must be carried on from each end; and all the débris excavated must be brought back the whole length of the boring, and all the air to be breathed by the workmen must be forced in. The provision of a fit atmosphere is a mere matter of detail. In the great Italian tunnel the machines were moved by compressed air, which, being liberated when it had done its work, supplied the lungs of the workers with fresh oxygen. The Alpine engineers, however, started from the level of the earth: the main difficulty of the Submarine Tunnel seems to be that it must have as its starting-point at each end the bottom of a huge well more than a hundred yards in depth. The Thames Tunnel, it will be remembered, was approached, in the days when it was a show place, by a similar shaft, though of comparatively insignificant depth. This enterprise may indeed be said to bear something like the relation to the engineering and mechanical skill of the present day which Brunel’s great undertaking bore to the powers of an age which looked on the Thames Tunnel as the eighth wonder of the world. Probably the danger which will be incurred in realizing the larger scheme is less than that which Brunel’s workmen faced.
“It is, of course, impossible for any estimate to be formed of the risks of this enormous work. They have been reduced to a minimum by the mechanical appliances now at our disposal, but they are necessarily considerable. The tunnel is to run, as we understand, in the lower chalk, and there will be, as M. de Lesseps told the French Academy, some fifty yards of soil—a solid bed of chalk, it is hoped—between the sea-water and the crown of the arch. Moreover, an experimental half-mile is to be undertaken on each side before the work is finally begun; the engineers, in fact, will not start on the journey till they have made a fair trial of the way. Altogether the beginning seems to us to be about to be made with a combination of caution and boldness which deserves success, even though it should be unable to command it. Unforeseen difficulties may arise to thwart the plans, but the enterprise, so far, is full of promise. The opening of such a communication between this country and the Continent will be a pure gain to the commercial and social interests on both sides. It obliterates the Channel so far as it hinders direct communication, yet keeps it intact for all those advantages of severance from the political complications of the Continent, which no generation has more thoroughly appreciated than our own. The commercial advantages of the communication must necessarily be beyond all calculation. A link between the two chief capitals of Western Europe, which should annex our railway system to the whole of the railways of the Continent, would practically widen the world to pleasure and travel and every kind of enterprise. The 300,000 travellers who cross the Channel every year would probably become three millions if the sea were practically taken out of the way by a safe and quick communication under it. The journey to Paris would be very little more than that from London to Liverpool. It is, however, quite needless to enlarge on these advantages. The Channel Tunnel is the crowning enterprise of an age of vast engineering works. Its accomplishment is to be desired from every point of view, and, should it be successful, it will be as beneficent in its results as the other great triumphs of the science of our time.”
The Channel Tunnel is not yet a fait accompli, although the preliminary trial works have been made at both ends. Drift-ways of some ten feet diameter have been cut beneath the waters of the strait, and instead of the experimental half mile mentioned in the foregoing paragraph, the works have been pushed forward on the English side for about a mile and a quarter with complete success. As was anticipated, no physical difficulties were met with, for the machines did their work with the greatest ease, and the drift has now remained for some years practically free from any infiltration of water. These results indicate that the scheme might be completed with speed and safety. Parliament, however, has refused to allow the undertaking to proceed, being moved to this course by the opinions of military authorities, who see dangers to England in the completion of this enterprise, or at least such a disturbance of the British complacency at the notion that our island might be reached otherwise than “by the inviolate sea,” that the whole land would be liable to terrors and alarms from invasion by stratagem. It is represented that huge fortresses and a special army for that purpose would become necessary to guard the mouth of the tunnel were it made. This is, perhaps, the kind of objection which such an enterprise could not fail to raise. But it can hardly be expected that all the commercial and international advantages which the realization of the scheme would undoubtedly secure are for ever to stand in abeyance for such opinions as have, for the present, caused the operations to be suspended. It has been pointed out that there are many ways of instantly rendering such a tunnel impracticable in case of a sudden alarm. But the necessity could only arise after a supposed paralysis or destruction of such army and navy as Britain could bring together to defend her land. Perhaps military skill will presently devise less costly methods of defence than those authorities now suppose the tunnel would require; or, even if such armaments were really necessary for our sense of insular security, the expense might be no unprofitable outlay for the advantages to be gained. It is satisfactory to know that the promoters of the scheme are sanguine of the subsidence of the military and political prejudices, which are now the only obstacles to its accomplishment. A somewhat unexpected result from the operations in connection with the experimental driftways has been the discovery, on the Kentish coast, of seams of coal underlying the chalk at a workable depth.