across Morecambe Bay, though in a greatly immense extent of sand and alluvial mud is though afterwards taken up by Mr. Hague, and left high and dry at low water. In this supported by Mr. Rastrick, it slept for many state it had long been a sort of desert high-years, until recently a line has been carried way for vehicles and foot-passengers. Lord Burlington, whose residence of Holkar House lies on the Cumberland side of the bay, in looking into some of the correspondence of his predecessors, found that when the family moved from London to the north there was no possibility of reaching Holkar within a reasonable time except across the sands, and preparations used to be made a fortnight or three weeks before the journey commenced, several trusty men being commissioned to meet the coach at Lancaster and conduct it safely on the way. Down to the past summer, indeed, a stage-coach plied across the sands from Lancaster to Ulverston-now superseded by the rail, and many are the hairbreadth escapes that occurred in the crossing. Nor did the travellers always escape the perils of the journey. The registers of the parish of Cartmell show that not fewer than a hundred persons have been buried in its churchyard who were drowned in attempting to pass over the sands. This is independent of the similar burials in other churchyards in adjacent parishes on both sides of the bay. Only in the course of last spring a party of ten or twelve young men and women, proceeding to the hiring market at Lancaster, were overtaken by the advancing tide, when every one of them perished. The principa danger arose from the treacherous nature of the sands, and their constant shifting during the freshets which occurred in the rivers flowing into the head of the bay. As early as the year 1837 Mr. George Stephenson recommended the construction of a railway from Poulton, near Lancaster, to Humphrey Head, on the opposite coast, as part of a west coast line to Scotland. He proposed to carry the road across the sands in a segment of a circle of five miles radius. His design was to drive in piles for the whole length, and form a solid fence of stone blocks on the land side of the piles, for the purpose of retaining the sand and silt brought down by the rivers from the interior. It was calculated that the value of the forty thousand acres of rich alluvial land thus recalimed from the bay would have more than covered the cost of forming the embankment. But the scheme was not prosecuted; and The people of the neighborhood regarded the scheme as one of the wildest that had ever been heard of. The idea of forming a solid road across about eight miles of sands, which from time immemorial had been to them the type of every thing that was shifting and unstable, appeared to be even more wild and absurd than that of the foolish man in the parable, who built his house upon a similarly treacherous foundation. The prophecies that were ventured upon the subject were only paralleled by those which predicted that a road could never be made across Chat Moss. Besides the washing of the railway embankment on the land side by the rivers flowing into the sea, there was the washing of the sea-waves on the other side to be provided against. The work during its progress was a daily encounter with dif ficulties, occurring at every flux and reflux of the tide; and when to the flow of the water was added the force of a southwesterly storm, the temporary havoc made in the embankments was calculated greatly to discourage the projectors of the undertaking. The principal obstacles were encountered in crossing the estuary of the Leven. In making the borings nothing but sand was found to a depth of thirty feet. In one case the boring was carried seventy feet down, and still there was nothing but sand. It was necessary, in the first place, to confine the channel of the river to a a fixed bed, which was accomplished by means of weirs formed of" quarry rid." No small difficulty was experienced in getting these weirs run out in the right line, in consequence of the eddies produced by the tide at its flux and reflux washing deep holes in the sand on either side To prevent these eddies undermining the foundations of the work, toes of loose stones ground would be too steep to be economically were run out, with lateral wings thrown off worked by the locomotive. The tunnel usufrom their ends, which had the effect of keep-ally occurs where a line crosses from the ing the holes made by the tide out of the head of one valley into the head of another, line of the embankment or main weir, which as from the Yorkshire into the Lancashire was then carried steadily forward. When valleys, under the rocky mountain-ridge the current had at length been fixed, a via- known as "the backbone of England." No less duct of fifty spans of thirty feet each was than three tunnels have been constructed thrown over the channel, and in the viaduct under this high ground: at Woodhead, on was placed a drawbridge to permit the pas- the Manchester and Sheffield Railway; at sage of sailing vessels. To protect the foun- Stanedge (formerly a canal tunnel), on the dations of the piers of this viaduct, as well as Huddersfield and Manchester; and at Littlethe railway embankment, weirs were also borough, on the Manchester and Leeds line. formed parallel with the current of the The usual mode of executing a tunnel is as stream, which had the further effect of re- follows. A careful preliminary examination taining the silt inland, and thus enabling is made of the geological strata, so far as large tracts of valuable land to be reclaimed. these can be discerned from the external The crossing of the Kent estuary was ac- features of the country; and levels or soundcomplished in a similar manner, by means of ings are taken, from which a profile of the weirs and embankments, over ground where surface of the ground to be passed under may the borings showed the sand to be of the be formed. To test the character of the depth of from fourteen to twenty-one feet; a underground strata, before letting the works viaduct of similar dimensions to that across to contractors, vertical borings are made the Leven, providing for the outfall of the through the site of the proposed tunnel, or river. The land reclaimed behind the em- trial shafts are sunk with the same object. bankments at this point is now under cultiva- No matter how thorough this preliminary tion, where only a short time since fishing-examination may be, the nature of the strata boats were accustomed to ply their trade. throughout cannot be ascertained with perThe chief difficulty which the engineer had to encounter was in finding a solid foundation amidst the shifting sands for the piers of the extensive viaducts across the mouths of the two rivers. The details of the plan he adopted for sinking iron piles would be too technical to be entered upon here. It is sufficient to say that the entire work has been satisfactorily achieved, and must be regarded as another triumph of English engineering over that element which usually tests their highest skill. fect accuracy; and it may so happen, as in the case of the Kilsby Tunnel, that the most dangerous part of the ground may not be disclosed. In some cases, where the tunnel is of no great extent, a driftway is dug through its whole length. But this cannnot be done when the work is extensive; and then the tunnel is commenced at various points, by means of vertical working shafts sunk from the surface down to the base of the tunnel. When this is reached, excavating, followed by building in of the brick or But greater obstacles than all that we have stone work of the tunnel, proceeds abreast yet described have been encountered in the each way, the excavated stuff being drawn up underground work of tunnelling. At a public the shaft by means of a horse gin, or by dinner at Norwich, during the railway mania, steam-power. The tunnel is usually worked it was facetiously suggested that directors in lengths of about twenty feet, and arched always liked "perfect flats to work upon." with brick or stone from eighteen inches to But few English counties are so flat as the two feet in thickness. By this method a Eastern, and there are not many lines of any large number of short tunnels are formed, extent in this country where it has been which in the course of the work are ultimately found practicable to dispense altogether with united into one, and a vast body of men can tunnelling. The undulating nature of the be employed without confusion at the same soil renders it necessary to bore where an time. The precision with which the survey is open road cannot be cut, where a detour to taken, and the line of the tunnel struck from avoid the high ground would be too circuitous, the shaft heads, is such that the various or where an inclined road over the high lengths, when completed, often meet each other to an inch-breadth, or less. Mistakes long, of the width of the canal, and exactly have, however, happened, when the lines have been struck by inexperienced surveyors, as in the case of a tunnel on a northern line, when the workmen in different lengths found on one occasion, from the noise made by the underground blasting, that they were working past each other. The error, which was repaired at considerable cost, had been occasioned by the curve at the bottom of one of the shafts having been accidentally laid out in the wrong direction. fitting the bottom. It was brought to the spot in three pieces, which were welded firmly together. The trough was floated into its place and sunk, and the railway works underneath were then proceeded with in safety. The difficulties we have been enumerating, have, nevertheless, been surpassed by those which have occurred in forming tunnels of great magnitude, such as the Box Tunnel on the Great Western Railway, the Woodhead Tunnel on the Sheffield and Manchester Railway, and the Kilsby Tunnel on the London and North Western Railway. In excavating the Box Tunnel, great quantities of water were met with. At one place heavy rains occasioned an immense influx, which "drowned out" the workmen, and not only filled the tunnel, but rose to a height of 56 feet in the shaft. The engineers had to go on pumping for months, though as much as 32,000 hogsheads were thrown out in the course of the twenty-four hours. One of the most delicate pieces of tunnel surveying and underground building was executed at Glasgow, on the short branch railway connecting the Garnkirk Railway with the Buchanan Street Terminus of the Caledonian Railway. It was found necessary to pass, by means of a tunnel 400 feet in length, under the Monkland Canal, and over the Tunnel of the Edinburgh and Glasgow Railway. There was barely space for the purpose, the floor of the one tunnel being only ten feet above the roof of the other. Any one who casts his eye upon a map of But to prevent the upper erection from rest- the county of Chester will observe a narrow ing heavily upon the lower one, arches of tongue of land at its easternmost corner, exseventy feet span were constructed, on which tending towards Yorkshire, between the the walls of the upper tunnel were supported counties of Derby and Lancaster. At this so that the entire weight was borne by the approximation of the four counties the solid ground on either side. The arch of the Woodhead tunnel penetrates the mountain tunnel was elliptical, and formed of bricks ridge for a length of about three miles under composed of a mixture of common and fire a dreary, barren moor, undisturbed save by clay; and in order to give additional strength the sportsman's gun. The usual shafts were an inverted arch of the same materials was sunk over the line of the tunnel down toturned below the rails. All this work was wards its base. The average depth of the performed underground; and, during its shafts was about 600 feet; but it was long progress, the difficulty of execution was in- indeed before the workmen could reach the creased by the breaking in of the waters bottom level. The sinking, blasting, and from the canal above. But this too was winding went on so slowly that the tunnel successfully mastered, and the two tunnels was six years in progress. This was caused now stand secure tier above tier, under the partly by the hardness of the material, and bed of the Monkland Canal. A similarly partly by the immense quantity of water delicate piece of work was executed on the which flowed into the shafts. The pumping North Midland Railway at Bullbridge, in continued for five years, during which time Derbyshire, where the line at the same point the engines threw up not less than eight passed over a bridge which here spanned million tons of water. At two of the shafts the river Amber, and under the bed of the where continuous pumping went on, not an Cromford Canal. Water, bridge, railway, inch was gained during nine months. In and canal, were thus piled one above the another it took eleven months to sink fourother four stories high. Such another curi- teen yards, the workmen coffering out the ous complication does not probably exist. In water as they descended with ashlar stoneorder to prevent the possibility of the waters work bedded in one-inch boards. But the of the canal breaking in upon the works of enemy was never fairly mastered until the the railroad, the engineer, (Mr. George Ste-under-drift was blasted through the line of phenson,) had an iron tank made 150 feet the tunnel, whereby the upper springs were THIRD SERIES. LIVING AGE. 3 tapped, and the water flowed out of the open ress of the work. A boy, who had been end of the tunnel by its own gravity. The blasting-work of this tunnel was so enormous that not less than three thousand five hundred barrels of gunpowder, weighing about one hundred and sixty tons, were used in its formation. The average number of men employed was about a thousand; and during the six years the works were in progress twenty-six men were killed, of whom sixteen were miners. One fell down an airshaft into the lower gallery when getting out of the way of a blast, his candle having gone out; three were killed by a discharge of gunpowder, in consequence of their stemming the blast-hole with rock instead of shale or other soft material; another had the stemmer blown clean through his head, while looking over another miner's shoulder, who was carelessly ramming down the powder with the head of his drill; another returned to the blasting-place before one of the shots had exploded, and was killed on the spot. There were about four hundred minor accidents, many of them attended with loss of limb, and the sum total of the casualties, in proportion to the men employed, was greater, according to Mr. Edwin Chadwick, than was suffered by the British army in the battles of Talavera, Salamanca, Vittoria, and Waterloo. The lives of workmen have occasionally been lost in other tunnels by sudden irruptions of water, the enemy most dreaded by miners. In excavating the tunnel of the Edinburgh and Granton Railway, directly under the New Town of Edinburgh, the driftway, about six feet square, which had been driven from both ends, was completed, with the exception of a barrier of earth about the middle of the work. The tunnel was on a heavy incline, and it was known that a considerable quantity of water had accumulated in the upper excavation. It appeared, how ever, that the drift had not been driven true, and that the southern and northern portions passed each other at the point where they should have met. The men in the lower drift were working by "double-shifts "-that is, night and day-and one morning, about six, when the night-shift was about to come off, a flood of water burst in upon them and drowned the two miners, with the ganger or foreman, and the brother of one of the contractors, who had gone to ascertain the prog sent down the shaft in Dublin-street, about seventy yards below where the barrier was, suddenly heard the fearful rumbling noise like thunder, and, fearing that the waters had burst, he instantly gave the signal to be pulled up. It was just in time; for he had no sooner been drawn out than the water came rushing up the shaft, which was about sixty feet deep, struck off the roof of the wooden shed which covered the opening, and rushed down Dublin-street in a torrent. Another water-difficulty occurred in constructing the Kilsby Tunnel of the London and North-Western Railway. The railway was forced in the direction of Kilsby by the opposition of powerful landowners in the counties of Northampton and Buckingham, who had not yet discovered the advantages of railways. A tunnel two thousand four hundred yards long, passing one hundred and sixty feet below the surface, was thus rendered necessary. The ridge under which it runs is of considerable extent, the famous battle of Naseby having been fought upon one of its spurs some seven miles to the eastward. Previous to the letting of the work to the contractors, the character of the underground soil was tested by trial-shafts, which indicated that it consisted of shale of the lower oolite. But scarcely had the job been commenced when it was discovered that, at an interval between the trial-shafts which had been sunk about two hundred yards from the south end of the tunnel, there existed an extensive quicksand under a bed of clay forty feet thick, which the borers had just missed. The excavation and building of the tunnel were proceeding at the bottom of one of these shafts, when a place in the roof suddenly gave way, a deluge of water burst in, and the party of workmen with the utmost difficulty escaped with their lives. They were only saved by means of a raft, on whicu they were towed by one of the engineers swimming, with the rope in his mouth, to the lower end of the shaft, out of which they were safely lifted to terra firma. Pumpingengines were erected for the purpose of drawing off the water; but for a long time the water prevailed, and sometimes even rose in the shafts. It was then thought expedient to run a drift which might act as a drain along the heading from the south end of the tunnel. The drift had nearly reached the sand-bed when, one day that the engineer, | Even with the enormous pumping power his assistants, and the workmen, were clus- employed, it often happened that the bricks tered about its entrance, they heard a sudden were scarcely covered with cement before roar as of distant thunder. It was hoped they were washed clean by the streams of that the water had burst in-for all the work- water which poured down overhead. The men were out of the drift-and that the sand workmen were accordingly under the necesbed would now drain itself in a natural way. sity of holding over their work large whisks Very little water, however, made its appear- of straw and other appliances to protect the ance, and it was found that the loud noise bricks and cement at the moment of setting. had been caused by the sudden discharge of The quantity of water thrown out of the an immense mass of sand which had com-sand-bed during the eight months of incessant pletely choked up the passage. No other pumping, averaged two thousand gallons per plan was now left than to have recourse to minute, raised from an average depth of 120 numerous additional shafts and pumping- feet. It is difficult to form an adequate idea engines placed over the line of the tunnel of the bulk of the water thus raised; but it where it crossed the quicksand, which in- may be stated that, if allowed to flow for volved a large additional expenditure. As three hours only, it would fill a lake one acre for the contractor, he gave up the work in square to the depth of one foot; and if aldespair, and died shortly after, killed, it was lowed to flow for one entire day, it would fill said, by the anxiety he had suffered. The the lake to over eight feet in depth, or suffidirectors, in this perplexity, called to their cient to float vessels of a hundred tons aid certain engineers of the highest eminence burthen. The water pumped out of the at that day, who advised the abandonment tunnel during the entire period of the works of the work, while Mr. Robert Stephenson, would be equivalent to the contents of the the Company's chief engineer, strongly urged Thames between London Bridge and Woolits prosecution. His plan was at length wich. Notwithstanding the quantity of water adopted by a majority of the directors. A line of pumping-engines, having an aggregate power of 160 horses, was erected at short intervals; shafts were simultaneously sunk down through the sand, and the pumping went on for eight continuous months until the tunnel at that part was completed. It was found that the water with which the bed of sand, extending over many miles, was charged was to a certain extent held back by the particles of the sand itself, and that it could only percolate through it at a certain average rate. Hence the distribution of the pumping power at short intervals along the line of the tunnel had a much greater effect than the concentration of that power at any one spot. The workmen, protected by the pumps, which cleared a space for their operations in the midst of two walls of water and sand, proceeded with the tunnel at numerous points. Every exertion was used to build along the dangerous part as quickly as possible, the excavators and bricklayers working night and day until the whole was finished. raised, the level of the surface in the tunnel was only lowered about two and a half to three inches per week, proving the vast extent of the quicksand, which probably extended along the entire ridge of land under which the railway passed. Such are only a few of the more prominent instances of the difficulties encountered in the formation of British railways. We have scarcely so much as alluded to the construction of viaducts and bridges, in which our engineers have also displayed the very highest skill in overcoming the obstacles interposed by nature. But the stupendous magnitude of these works is perhaps less remarkable than the rapidity of their execution, the amount of capital which they have absorbed, and the still greater amount of capital they have created. Taken as a whole, they bear stamped upon them an impress of power unequalled by the structures of any other era and nation; and future generations may point to them as eminently characteristic of the iron age of England. |