London, Volume 3
Knight, Charles
1842
LIV.-The Thames Tunnel.
LIV.-The Thames Tunnel.
Whatever may appear to the eyes of landsmen, to the British sailor it is, without doubt, a region of romance; a place to think about when-having been long tossed on some sea, or, more intolerable annoyance, becalmed on some far-stretching dead waste of waters-his heart yearns towards home; and the spot, made so familiar to him by the songs and stories he most delights in,the spot where he has so often touched English ground after many months' absence,--rises to his imagination decked in fairer and more glowing hues than poet or painter ever lavished on places a times more beautiful. go through its long and narrow streets thinking nothing of all this, and turning up our noses at its dirt, and age, and squalor; but the sailor's respect for us is not so remarkable as to make that circumstance trouble him : we verily believe, if he told | |
50 | the truth, he would acknowledge he liked the better for its disagreeables. And after all, it may be questioned
whether he does not love as as See the attention every here pays to him. From the moment we pass , and those immense warehouses to the right-rising story upon story, and large enough, apparently, to be the storehouses of an empire rather than of a single metropolitan dock (St. Katherine's)-every other shop is in some way or other devoted to wants, instruction, recreations; or to the wants of what he is quite as anxious about as his own, those of his good ship. Here we have the wholesale slopseller occasionally condescending to throw a half-unpacked bundle of jackets or shirts into his window, and who can at the briefest notice rig out a ship's crew: there the retail dealer, who is not too proud to exhibit nearly his whole substance to the light of common day, and covers his entire front, from the pavement to the floor, with snow-white ducks, and rough pilot coats, oilskin overalls, and every variety of hat, from the small jaunty round to the coalheaver fashioned, with the long descending piece behind. Then there are the ship-joiners, and ship-carpenters, and ship sail-makers-each a numerous race. The aristocratical shop-keeper of we take to be the mathematical instrument-maker, whose windows, so full of neatly-finished and highly-polished brass articles, in so many varieties of form, might even cut a figure in : sea-charts and sounding-machines, telescopes, compasses, and quadrants,--these are his staple commodities. The book-stall is equally characteristic of its customers and the place. A glance over its literature will at once show you your precise latitude and longitude. Side-by-side you see and
and ready to tempt some Incledon of the deck with a promise of a fresh accession of strength for the next trip. |
But the general visitor may find much in to excite his attention, without having a sailor's sympathies. The , for instance, occupying above acres, with their truly vast tobacco and other warehouses, are here. And the historical memories are not destitute of interest. It was in that the infamous Jeffreys, when James II. abdicated the throne, sought to shelter himself from the popular indignation, but in vain: he was detected in spite of his disguise as a common seaman, cudgelled, and hurried off to the Tower, where he died a few days after. The name of of the outlets to the Thames preserves the memory of many a terrible tale of murder and piracy on the high seas: it was at , still known by that name, that all pirates used to be executed; and it appears, from an anecdote recorded by Maitland in his History,[n.50.1] not pirates only, but sailors found guilty of any of the greater crimes committed on ship-board. He states that, The pirates were | |
51 | formerly hung about
low-water mark, and left till tides had overflowed them. This custom
is of old date, for Stow mentions it as usual in his time. The same writer adds that
till within years of the period at which he wrote, the close of the century; he continues, [n.51.1] The cause of the building of the part of (that near the river) is curious. The manor being continually overflowed with water, the Commissioners of Sewers originated the idea of building houses on the banks, on the principle that the tenants would be sure to take effective measures for the preservation of their lives and property. The idea was good, and, being carried into practice, successful. This was the commencement of . And thus may be explained a circumstance that excited some surprise in sinking the shaft of the great work which forms the subject of this paper. Houses previously stood on the spot, which were removed for the shaft; and at some distance below their foundation were found the relics of a ship-builder's yard, including part of a slip, a ship's figure-head, and a great quantity of oak. |
Such is , the place at extremity of the Thames Tunnel; to reach the other, , we must yet for a brief space avail ourselves of the boatman and his graceful wherry. As we are crossing, let us recall a few recollections of the early subaqueous excavations attempted or accomplished in England. Beneath the Tyne and Wear are passages made by the coal-miners, extending from side to the other; and at Whitehaven an excavation made by these men extends for upwards of a mile under the sea. Mr. Dodd believes the of these in point of time to be that in the Wylan Colliery, crossing below the bottom of the Tyne.[n.51.2] These works were of course very simple and easy, or they would not have been attempted. It was towards the close of the last century that something much more arduous was proposed by the gentleman we have mentioned, an engineer of reputation. He says, Circumstances caused the abandonment of the scheme. He next proposed a Tunnel from Gravesend to Tilbury; and it is interesting to observe how similar its chief features were to have been to those of the present Tunnel. Like that, its form was to be cylindrical, with a drain beneath, and a dip of the whole work in the centre of the river. The plan was much approved, public meetings were held, a government survey made with a favourable result, a subscription-book opened which rapidly filled, and at last operations commenced by the sinking of a well on side; when so much water was found, that the whole affair was abandoned | |
52 | as impracticable.[n.52.1] or years after this an attempt was made,
only a mile below the present Tunnel, to connect and , by an
experienced Cornish miner of the name of Vesey. A company was formed under the title of the
Thames Archway Company, an act of parliament obtained, and the work begun. A shaft of feet in diameter was sunk to the depth of feet: to avoid certain difficulties, it was then contracted to feet, and thus continued to the depth of feet.
The horizontal excavation was there begun, in the form of a driftway, to be afterwards widened
into the required dimensions for a passage, and carried to within feet of the Middlesex shore, when the engineer of this attempt had also to report that further progress was impracticable. or years were thus expended, during which the
talents of different engineers had been put in requisition, and
rewards offered for plans, which brought in communications from all quarters. It was under the
remembrance of these discouraging circumstances that Mr. (now Sir M. I.) Brunel appeared before
the public with a new proposal in , which it was stated had received the sanction of many eminent persons, in
particular of the Duke of Wellington and Dr. Wollaston. The mere idea of a Tunnel below rivers
is of course a matter of little moment, whoever the originator--the doing it everything. The
novelty of Mr. Brunel's proposed mode of operation, therefore, was rightly judged of great
importance. That gentleman has himself explained the origin of his idea. The writer of the
article in the states that he was informed by Mr. Brunel To the practical form which the idea thus given assumed we shall revert presently. |
in this, as in the preceding instance, was chosen as the starting-place of the Tunnel, though the precise spot was a mile nearer to the city. Unlike , (or Redriff, as it is often corruptly called) is of great antiquity; and, were it from circumstance only, of considerable historical interest. It was here that the famous trench or canal of Canute was commenced, in order that the invader might avoid , an account of which has been given in our notice of that structure.[n.52.2] In the reign of Edward III. a great navy was fitted out at , under the care of the Black Prince, for the invasion of France. And, lastly, it was off that Richard II. was so alarmed at the shouts and the array of the malcontents whom he came to appease, that he returned hastily to the Tower; whilst the infuriate people, led by kind of wrong from which they suffered, into the commission of another of which they were the inflictors, swept on to the Marshalsea and , and committed the excesses already frequently referred to. , like , has its numerous docks, a similar population, and presents generally the | |
53 | same features. But there are some circumstances which distinguish the Surrey from the Middlesex side: we may instance its numerous flour-mills, the various manufactories, and the wharfs for the coasting-trade of England which are all to be found between the Tunnel and . The importance of a new mode of communication between such places, only some feet apart geographically, but miles by the way of , will be at once apparent. But it is still more so, if we consider for a moment the peculiar connection between the great interests which belong to the different sides of the river. An immense amount of the foreign goods brought into the West India, the London, and St. Katherine's Docks, on the north side, is absorbed by this coasting-trade on the south; and, it appears, is almost entirely conveyed from to the other by land carriage. During the year , of waggons and carts which passed over southwards, no less than of the , and of the , turned down --half of which are supposed to be engaged in the traffic mentioned. The accommodation a Tunnel may afford to passengers receives a striking illustration from the returns made to Parliament of the watermen engaged at the different ferries in the neighbourhood, who were in number, and calculated to take, on an average, not less than passengers daily. An important consideration is deducible from the position of the Tunnel: it will have no expensive approaches to form. On the north it is connected, through , with Ratcliffe Highway, and a new road is projected in continuation of the former to the and Whitechapel. On the south it is close to the . All these places will, of course, assume a new character when the influence of the new traffic shall reach them. |
In the beginning of Mr. Brunel had the satisfaction to see the and least arduous, but still indispensable, step secured, the formation of a Company with the express object of carrying his designs into execution, and by whom an Act of Parliament was obtained. The Company took the preliminary precaution of having parallel borings made beneath the bed of the Thames in the direction of the proposed Tunnel, when the report was so very favourable that, | |
54 | in consequence, Mr. Brunel went to work in a somewhat bolder way than he had otherwise intended. The soil was the great object of deliberation, for upon it depended at what level the Tunnel should be commenced. The assistance of some eminent geologists was here of great moment. These informed the engineer that below a certain depth the soil would be a kind of quicksand, and therefore advised him to keep above it, and as close as possible to the stratum of clay forming the bed of the river. We shall presently see that the geologists were right. |
We are not about to give a technical description of the progress of the works of the Tunnel, which could be interesting alone to the professional or scientific man; but we must notice at some length or of their chief points, not only because the success of the work has depended upon them, but because in their admirable simplicity, as well as their wonderful fitness to the purposes designed, they cannot fail to be universally understood and appreciated. | |
And of the construction of the shaft with which the Tunnel was commenced in . This seems to our eyes, uninitiated in the wonders of engineering, not of the least marvels of this altogether marvellous work. A space being marked out a feet distant from the river, the bricklayers began raising a round frame, or cylinder, feet thick and feet in circumference. This was strengthened in various ways, by iron rods, &c., passing up the centre of the thickness; and was continued to the height of feet. The excavators now commenced their work on the inside, cutting away the ground, which was raised to the top of the shaft by a steam-engine there placed, and which also relieved them from the water that occasionally impeded their descent. We may imagine the wonder with which a person unacquainted with the object of these preparations must have beheld that enormous mass of masonry at last beginning to descend regularly and peacefully after the busy pigmies who were carving the way for it, and at the same time, as it were, accommodating itself to the convenience of the bricklayers, who, in order to give it the additional height required, had merely to keep adding to the top as it descended. This is the history of the great circular opening into which the visitor passes from the little lobby, and where he beholds, in the centre, an elaborate machinery of pumps, connected with a steam-engine, raising its gallons per minute, and, as though that was really too trifling for an engine of its respectability of power, performing into the bargain the duties of drawing carriages along the railway, which as yet occupies of the arches of the Tunnel, and that of hoisting and letting down all the heavier articles passing between the upper and lower world. We must not omit to observe, with regard to the shaft, that by its means the bed of gravel and sand feet deep, full of land-water, in which the drift-makers of the earlier attempt had been compelled to narrow the dimensions of their already small shaft, was passed without inconvenience. We may add also that, when the shaft was sunk to its present depth of feet, another shaft, of feet diameter, was sunk still lower, till, at the depth of feet, the ground suddenly gave way, sinking several feet, whilst sand and water were blown up with some violence. This confirmed the statement of the geologists, and satisfied the engineer as to the propriety of the level he had chosen. | |
55 | |
The shaft accomplished, the Tunnel itself was begun at the depth of feet. The excavation Mr. Brunel proposed to make from bank to bank was to be about feet broad and and a half high, which, being defended by strong walls, was to leave room within for a double archway, each feet high, and wide enough for a single carriage-way and a footpath. The mode in which this great excavation was accomplished has been the wonder and admiration of the most experienced engineers, and will for ever remain a monument of the genius of its author. The engravings before us represent | |
56 | views of the working of the , by means of which the weight of the superincumbent bottom of the river has been supported, whilst the men who were undermining it were sheltered in its little cells below. This mighty instrument- in idea and object, but consisting of separate parts or divisions, each containing cells, above the other--is thus used. We will suppose that, the work being finished in its rear, an advance is desired, and that the divisions are in their usual position--the alternate ones a little before the others. These last have now to be moved. The men in their cells pull down the top poling-board, of those small defences with which the entire front of the shield is covered, and immediately cut away the ground for about inches. That done, the poling-board is replaced, and the below removed, and so on till the entire space in front of these divisions has been excavated to the depth of inches. Each of the divisions is now advanced by the application of screws- at its head, and at its foot-which, resting against the finished brickwork, and turned, impel it forward into the vacant space. The other set of divisions then advance. As the miners are at work at end of the cells, so the bricklayers are no less actively employed at the other, forming the brick walls of the top, sides, and bottom--the superincumbent earth of the top being still held up by the shield till the bricklayers have finished. This is but a rude description of an engine almost as remarkable for its elaborate organization as for its vast strength. Beneath those great iron ribs a kind of mechanical soul really seems to have been created. It has its shoes and its legs, and uses them too with good effect. It raises and depresses its head at pleasure; it presents invincible buttresses in its front to whatever danger may there threaten, and, when the danger is past, again opens its breast for the further advances of the indefatigable host. In a word, to the shield the successful formation of the Tunnel is entirely owing. We may add that following the shield was a stage in each archway for the assistance of the men in the upper cells. |
But, great as was the confidence of Mr. Brunel in his shield, and the resources which he must have felt he had within himself, ready for every difficulty, it is impossible that he could have ever anticipated the all but overwhelming amount of obstacles that he has actually experienced, principally from the character of the soil, and the extraordinary influence which the tides exercised even at the Tunnel's depth. The feet of the Tunnel (commenced with the new year, ) were passed through firm clay; then came a loose watery sand, where every movement was made with imminent hazard. anxious days passed in this part. Substantial ground again reached about the , matters went on prosperously till September following, by which time feet had been completed. On the of that month the engineer startled the Directors with the information that he expected the bottom of the river, just beyond the shield, would break down with the coming tide. It appears he had discovered a cavity above the top of the shield. Exactly at high tide the miners heard the uproar of the falling soil upon the head of their good shield, and saw bursts of water follow; but so complete were the precautions taken that no injury ensued, and the cavity was soon filled by the river itself. Another month, and a similar occurrence took place. By the , feet were accomplished, when the tide, during the removal of of the poling-boards, | |
57 | forced through the shield a quantity of loose clay; but still no irruption of the river itself followed--the fear of which, from the commencement to the termination of the work, was continually upon every 's mind. From January to April the Tunnel proceeded at an excellent rate, although the ground continued so very moist that, in the latter month, an inspection, by means of a diving-bell, of the bed of the river became necessary. Some depressions were observed, and filled up by the usual means-bags of clay. A shovel and hammer, being accidentally left on this occasion in the river, were afterwards found during an influx of loose ground through the shield, having descended some eighteen feet. This little circumstance shows the nature of the ground above, and the all but invincible difficulties through which the engineer had to make his way: But the more important incidents of the work-those which were to put his ability and fortitude to the severest tests--were now coming on. About the middle of May, some vessels, coming in at a late tide, moored just over the head of the Tunnel. The consequence was, that the obstruction they presented to the water caused a great washing away of the soil beneath. What followed may be best described in the words of Mr. Beamish, the then resident assistant-engineer, with whose Report of this, the irruption of the river, we have been favoured among other interesting matter, and which we give as a perfectly dramatic view of the scene, the actors, and the event. |
| |
The diving-bell being again employed, and the hole or chasm discovered, some bags of clay, armed with small hazel rods, were expended before it was effectually closed. On the of the next month the water in the Tunnel was got under; but it was not till the middle of August that the soil forced in was completely cleared away, and the engineer able to examine the effect of the irruption on his work. The structure was found perfectly sound, even whilst a part of the brick-work close to the shield was reduced to nearly half its original thickness by the tremendous violence of the rushing waters, whilst the chain which held the divisions of the shield together had been snapped like a twig, and whilst various heavy pieces of iron belonging to the shield were found driven into the ground as if by a battering-ram. Progress was now recommenced; and here we would pause a moment to pay a just tribute of admiration to the men, as well as to their directors, for the courage they have so constantly evinced. Even now, as they resumed their labours with the impression of the recent event fresh upon their minds, something or other was constantly occurring to excite fresh alarm. Now a report would take place in the frames like a cannon-shot, some part having | |
59 | been suddenly ruptured; now alarming cries
were heard, as some irruption of earth or water impetuously poured in. With the bursts of soil
and water would be felt large quantities of carburetted and sulphuretted hydrogen, which,
presently igniting with an explosion, would wrap the place in a sheet of flame. Beautiful at
such times to those who had coolness to admire it was the appearance of the mingling fire and
water, the flame appearing to dance along the surface of the liquid. And to what may we not get
accustomed? Those philosophers, the miners and bricklayers, used to look quietly on at the cry
of or, if they did make any observation, it was nothing more important than a prudent piece of advice, such as But perhaps, of all the difficulties overcome or endured, none have been more serious to the men than the impurity of the air; especially in summer, when the most powerful labourers had frequently to be carried out in a state of insensibility. Headaches, sickness, eruptions on the skin, were matters of too common occurrence to be noticed. Such a combination of circumstances must have given a strange colour to the lives of these labourers. An accurate description of the feelings and thoughts of the more imaginative would no doubt be as interesting as a romance. They have felt, and rightly, that a part of the true glory which belongs to such a work was theirs; and such feelings elevate even ordinary men. They have served also a kind and thoughtful master. It was touching to hear the terms in which of the miners spoke to us of him. As in their waking hours these men could have had no thought but of the Tunnel, so no doubt did the eternal subject constantly mingle with their dreams, and harass them with unreal dangers. amusing instance may be mentioned. Whilst Mr. Brunel, jun., was engaged midnight superintending the progress of the work, he and those with him were alarmed by a sudden cry of followed by an appalling silence. Mr. Brunel hastened to the spot, where the men were found perfectly safe. They had fallen fast asleep from fatigue; and of them had been evidently dreaming of a new irruption. |
By , the middle of the river had been reached; and, whatever the dangers and difficulties experienced up to that time, there was the gratification arising from their having been completely overcome without the loss of a single life. That gratification was to exist no longer. Even the very completion of the Tunnel was now to become a grave matter of doubt, and its projector to be left for long years in the sickening suspense of hope deferred on a matter wherein he had risked his professional reputation, and to which he devoted his entire energies-we might almost say, without exaggeration, his life. says Mr. Brunel, junior, in a letter written to the Directors on the fatal Saturday, , The scene at the shaft was truly deplorable. At period there were no less than eighteen men immersed, all of whom, with the exception of the unfortunates who perished, were taken out in an exhausted state, and some of them fainting. The noise in the shaft, created by the influx of the water, is described as having been absolutely deafening. The news rapidly spread about the neighbourhood of the Tunnel; and before it was known who were lost and who saved, the wives and relations of the workmen were rushing in, and adding to the confusion and distress of the scene by their wild gestures and exclamations. The water, as we have seen, actually bore Mr. Brunel up to the top of the shaft, and then still rising, flowed over even to the visitors' lodge. It was then evident that all who were still below had perished. | |
This calamity occurred at a critical time. The funds of the Company were exhausted: their confidence, in some measure, now failed too. After descents in the bell, the rent was discovered, and most formidable were its dimensions. It was of oblong shape, quite perpendicular, and measuring about feet in its longest direction, from east to west. The measures so often before and afterwards resorted to with success were adopted. of soil, principally clay in bags, were laid in the place. When they re-entered the Tunnel there was the melancholy satisfaction of seeing the work as substantial as ever, but there was but too much reason to fear it was of little consequence the completion might now never take place. What with the accident, and what with its consequences, we need not wonder to find it stated that the engineer appeared | |
61 | almost in a state of frenzy. For years from that time all was silence and darkness beneath those hollow roofs; and had the matter thus ended, what would have been the judgment of posterity? The plan had failed; and many of that immense array of projectors, , who now poured in their plans upon the Directors, would have lamented, with delightful self-forgetfulness, that Mr. Brunel had not adopted their schemes. But the Tunnel to be completed-he to be the man. |
In , the arches of the Tunnel were at last unclosed. Government, after repeated applications, agreed to make advances for the continuation of the work, which was accordingly once more carried forward with renewed energy. Very slow, however, was the progress made. Of weeks, feet inches only per week were accomplished during the eighteen, feet inches per week during the eighteen, foot per week during the eighteen, and during the last weeks only feet inches altogether. This will excite little surprise when we know that the ground in front of the shield was, from excessive saturation, almost constantly in little better than a fluid state, that an entire new and artificial bed had to be formed in the river in advance, and brought down by ingenious contrivances till it was deep enough to occupy the place of the natural soil where the excavation was to be made, and that then there must be time allowed for its settlement, whenever the warning rush of sand and water was heard in the shield. Lastly, owing to the excavation being so much below that of any other works around the Tunnel, it formed a drain and receptacle for all the water of the neighbourhood. This was ultimately remedied by the sinking of the shaft on the side. Yet it was under such circumstances that the old shield injured by the last irruption was taken away and replaced by a new . If our readers consider for a moment the and most important office executed by this engine, that it alone bore up above and kept back in front the incalculable pressure of the river and its bed, we may appreciate the opinions of engineers when the idea was started: was their common remark; yet it was done without the slightest derangement of the ground, or the loss of a single man. The most serious evil attending these delays and difficulties was the extra expenditure they involved, which became so great that the Lords of the Treasury declined further advances without the sanction of Parliament. A Committee was in consequence appointed, and witnesses examined, including of course the chief and assistant engineers. The result was favourable, and the work proceeded. On Wednesday, , a irruption occurred, but happily without any fatal consequences, or without materially retarding the works. An interesting escape marks this event. The water had gradually increased in quantity at the east corner since P.M., rushing into the shield with a hollow roar as though it fell through a cavity. A boat was taken out of the river and sent down into the Tunnel for the purpose of conveying materials (for blocking up the frames) down to the shield. Notwithstanding all that could be done by the men, the water gained upon them and rapidly rose in the Tunnel. About o'clock, the water having risen to within feet of the crown of the arch, and everything having been done that could be effected for the security of the work, it was thought most prudent for the men to retire, which they did in a very orderly | |
62 | manner along a platform which had been most judiciously and providentially constructed for that purpose in the east arch only a few weeks before by Sir I. Brunel's orders. After the men had retired, and as the water continued rising gradually, Mr. Page, the acting engineer, accompanied by Mr. Francis, Mr. Mason, and of the men, got into the boat for the purpose of reaching the stages to see if any change had taken place; and, after passing the feet mark in the Tunnel, the line attached to the boat ran out, and they returned to lengthen it. To this accident they were indebted for their lives; for while they were preparing the rope the water surged, running up the arch or feet. Every made his way to the shaft, and Mr. Page, fearing that the men would be jammed in the staircase, called to them to go up steadily; but they, misunderstanding him, returned, and it was with some difficulty that they could be prevailed upon to go up. Had the rope been long enough, all the persons who were in the boat (which was in a sinking condition when they grounded) must inevitably have perished in the surge, for now not less than a million gallons of water burst into the Tunnel in the course of a single minute. The lower gas-lights were then under water; and the pipes being but partially filled, the remainder burnt very irregularly, leaving the Tunnel almost in darkness, and then, flaming up to the top of the glasses, threw a blaze of light over the west arch and the water. When the water had risen to within feet of the entrance to the Tunnel, it came forward in a wave; and Mr. Page, Mr. Mason, and Mr. Francis, who were at the bottom of the visitors' stairs, ran up to the landing, but were so rapidly followed that of the party was up to his knees before he reached the top. other irruptions of the Thames complete this part of the history of the Tunnel. The occurred on the , when the water burst in about in the morning, and speedily filled the Tunnel. The excellent arrangements provided for escape secured the safety of the or more persons in it at the time, with exception. When the roll was called there was no answer to name. Inquiry being made, some it appeared had seen a miner returning towards the shield when all else were leaving it, and that was all that was known of him. |
The and last irruption occurred on the morning of the , and was remarkable for the noise resembling thunder with which it was accompanied. Happily no loss of life occurred. All this while the Tunnel was every week approaching nearer and nearer to the goal of the engineer's hopes-the opposite shore; and all parties began to feel the buoyancy of assured success inspiring them as they found the difficulties grow less and less formidable. They were, however, still sufficient to have paralysed any less energetic spirits than those who had brought the whole to that point. Here is an incident of so late date as :--On the , about o'clock in the morning, being then about low water, the top face of No. was attempted; but no sooner was the poling-board removed than the canted over, and a quantity of gravel and water rushed into the frame, forcing out another of the boards. At the hole thus left unprotected, the ground rushed in with such impetuosity as to knock the men out of the shield; and they, being panic-struck, ran away, but, finding that the water did not follow, they returned to the scene of action, and after immense exertions succeeded in stopping the run, when upwards of | |
63 | cubic feet of ground had fallen into the Tunnel. The rush of the ground was attended with a very great noise, resembling the bursting of a thunder-cloud, and a general extinguishing of the lights. While this was taking place in the Tunnel, a still more unusual phenomenon was occurring on the shore at , where, to the astonishment and dismay of the neighbourhood, the ground commenced sinking gradually over an area of upwards of feet, leaving a cavity on the shore of about feet in diameter and in depth. It was most fortunate that this occurred at low water, for at high water an irruption of the river would have been the inevitable consequence. A number of men were sent over, and the hole was filled with bags of clay and gravel, and everything rendered perfectly secure by the return of the tide. |
With another incident of the same year of a somewhat similar nature, we conclude these notices of the the and, in a sense, by which have marked almost every few months of the lives of the labourers in this great and hazardous undertaking. It appears that frequently the sand, mixing with water, so as to be quite in a fluid state, would ooze through the minute cracks between the small poling-boards, leaving immense cavities in the ground in front. A remarkable instance occurred upon the . The sand had been running in this way the whole of the night, and had completely filled the bottom of the shield. In the morning, on opening of the faces, a hollow was discovered extending upwards of eighteen feet along the front of the faces, projecting feet into the ground, and being about the same in height. This enormous cavity was filled with brickbats and lumps of clay, of the miners being obliged to lay himself the whole length of his body into the faces for the purpose of filling the farther end; and of course at the hazard, every moment he continued in his position, of being buried beneath fallen masses of earth, now left without any support from below. | |
The reward for every difficulty, anxiety, or suffering, was at last obtained. It is pleasant even to have to record that, on the , Sir Isambert Brunel passed down the shaft recently erected on the side of the river, and thence by a small driftway through the shield into the Tunnel. Under what a new aspect that beautiful double archway must have thence appeared even to him, whose eyes had not for a single day forgotten to look upon it for many years! And, as he turned, what power must have been felt in that little beam of light struggling through the driftway! The world must have appeared brighter from that moment. Nor should the labourers be forgotten, who, whilst expressing their admiration of him who had given method, firmness, and prosperity to their labours, in the cheering with which they greeted his appearance in the Tunnel from the opposite shore, deserve their meed of respect and applause. | |
The Tunnel is now entirely completed (measuring feet), and it is in order to make the necessary preparations for opening it to the public for use that it is now closed against mere visitors, The great circular shafts are being provided with handsome staircases for the accommodation of foot-passengers. The carriage-ways have yet to be constructed, and will be costly works. Their plan is marked with the inventive ability that so eminently characterizes the whole history of the Tunnel. They will consist each of an immense spiral road, winding twice round a circular excavation feet deep, in order to | |
64 | reach the proper level. The extreme diameter of the spiral road will be no less than feet. The side of the road next to the interior, or excavation, will be defended with substantial walls relieved by open arches; and on the other will be built warehouses at the top, and cellars at the bottom. The road itself will be feet wide, and the descent very moderate. The expenses of the Tunnel have been, of course, very much greater than were contemplated, and that circumstance has not been of the least of the engineer's difficulties: in sense, indeed, it was his greatest, since it did not rest with himself to conquer it. Yet, strange to say, in spite of such an accumulation of hindrances and obstructions as no man could have ever conceived could have been met with-and overcome, the expenses of the Tunnel forms of its advantageous features, when we contrast its cost with the only other mode of communication (impracticable here from the size and number of the shipping passing to and fro)-a bridge. We do not know the exact expenditure up to this moment, but we do know that the entire expense will not materially exceed the estimate presented to Government in by Mr. Walker, the engineer it had appointed to examine from time to time the state of the work, and its probable cost. At that period of the Company's capital had been expended, and worth of Exchequer bills advanced by Government, making together The estimate for the future consisted of items, of to complete the Tunnel, and the other of for the shaft on the side, the great circular approaches, &c., forming a grand total of And this, we are informed, will be about the actual expense. By the side of this we may place the cost of the latest in erection of the great metropolitan bridges, London, with its expenditure of millions; or, if the disparity between the positive utility of the works be objected, we may mention Waterloo, which has cost above a million. |
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Footnotes: [n.50.1] Vol. i. p. 591. [n.51.1] Survey, 1633 , p. 461. [n.51.2] He mentions an amusing story connected with this passage. A cow was grazing near the air-shaft built on one side of the river, when she accidentally slipped into it, and fell or rather rolled from side to side downward to a depth of a hundred and ninety-two feet, without serious injury. We may imagine the amazement of the colliers at work at the bottom. They drove the animal through the passage to the other side of the river, where she was taken up by the usual means of ascent to the top, and immediately swam back to her own meadow. [n.52.1] Reports, with Plan, Sections, &c., of the proposed Dry Tunnel, or Passage from Gravesend, in Kent, to Tilbury, in Essex, by R. Dodd, Engineer. 1798 . [n.52.2] Vol. i. p. 77. |
