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enables transit of goods in that part of Europe to be carried out at a very cheap rate, has for its basis a reservoir situated in in the high region running, roughly, westward from the Vosges, which high land acts as a watershed between the streams flowing towards the Atlantic and those flowing towards the Rhine basin on the east and the Rhone to the south. To form this reservoir a dam of stone, about a quarter of a mile long and some 60 feet high, had been built by the French Government in the late Seventies, not long after the FrancoGerman war, when public funds were by no means excessive. Whether it was due to an exaggerated idea of public_ economy, or whether the French engineers had allowed theory to have too prominent a place, is now a matter of conjecture; but whatever was the cause, the weakness of the dam manifested itself as soon as water was admitted into the reservoir, about eleven years before the disaster actually occurred. The dam then bulged or bent into a curve, with cracks in the masonry, which allowed a considerable quantity of the water to escape. It was evident that this was a very dangerous state of affairs, and consequently the reservoir was emptied, and certain consolidation works were built, which in due time were completed apparently in a satisfactory manner, so that for some six

[blocks in formation]

time, however, the original cracks were still there, and there can be little doubt that, in some form or other, they contributed to the ultimate wreck of the work.

The winter of 1894-95 was, all over Northern Europe, of exceptional severity. Even in England, tidal rivers such as the Thames and the Medway were frozen over, and there is no doubt that in the upland regions of France the frost must have been intense. Just as the householders' pipes burst when a severe frost occurs, but do not show the disagreeable consequences till the thaw comes, so it is probable that, on a larger scale, the full effects of the severe weather did not manifest themselves at this reservoir until spring came. Such, at least, is one theory, which may account for the disaster, although it must be admitted that this is not the only view of the case taken by the scientists of Europe, to whom this failure has afforded abundant material for theoretical investigation.

Whatever may have been the cause, the crash came at five o'clock on a spring morning. In the valley below the dam, some 10 miles long, leading to the Moselle, there were four small villages, inhabited for the most part by peasant farmers, many of whom, fortunately for them, were at that hour already up and working in their fields. The valley is not a narrow gorge, but a wide depression in an undulating country, with gentle slopes clothed with cultivation.

The pressure of the water in all sorts of carriages and appears suddenly to have over- on foot were going out over come the resistance of the dam the dusty roads to see the at the centre, where cracks sight, and small booths supplyhad already weakened it. Two ing refreshments were thronged great blocks of masonry, weigh- with thirsty bond fide travellers. ing many tons, appear first One of my companions was to have been overturned, and a German professor of great then on either side of the scientific knowledge, who, like breach, for a total length of the wranglers, played with the about 180 yards, the wall was symbols of high mathematics. carried away, and the pent-up To see him, with pencil and water poured forth on its diagram, differentiate and indevastating career. Huge tegrate, was a sight to strike blocks of masonry were swept ordinary mortals dumb with down for distances of 200 or admiration. But, like the rest 300 yards. The four villages of us, he was not averse to the were swept away, with attractive pressure of flowing loss of life of about eighty liquid in the form of refreshing people,a death roll which, drinks. What he considered though very terrible, would as the cause of the disaster have been much greater if was, however, not very evident, the dam had burst a few as his views were expressed in hours earlier. such involved terms as were beyond the capacity of one whose German is confined to the needs of ordinary hotel life. The views, however, generally expressed by the experts were to the effect that the original cracks were considerably augmented by the differences of temperature. Expansion and contraction from this cause are inevitable in all large masses of masonry, and where the range of the thermometer is greatest there will the effect be most palpable.

I visited the scene of the disaster about a fortnight after it occurred, in company with the superintending engineer of the district and a small party of French and German experts. It was a lovely day in early summer, all nature seemed rejoicing in new life, and it was hard to realise the terrible nature of the catastrophe until we actually reached the spot. Then, indeed, the overwhelming force of the torrent was at once in evidence. The whole valley below the dam was literally strewn with huge blocks of masonry, and all superficial soil had been swept away, leaving the bare and fissured underlying rock exposed everywhere. But, with the characteristic gaiety of the people, little parties of excursionists

I was discussing this point about a year ago when visiting the Assouan Dam with the resident engineer of the works there, and he remarked: "In fact, the whole dam keeps opening and shutting like a concertina "a singular expression to use for a work

which appeared to be of a solidity not even surpassed by the Pyramids. Yet such is the fact, though it is only a dangerous fact when the results are unknown and beyond human skill to control.

Whether it was from this cause, or from general distrust of a stone wall as a barrier against water-pressure, I know not; but the fact remains that, until the latter half of the last century, masonry dams were practically unknown in England. The man who had the courage to introduce them in a form at once safe, novel, and economical was one whom death has recently removed from among us one whose name, perhaps, is little known outside his own profession and private circle of friends; but it deserves to be ranked with the greatest engineers of the Victorian age George Frederick Deacon. He it was who devised the great stone dam that created Lake Vyrnwy in Wales, and provided the city of Liverpool with a matchless supply of pure water. He it was who, with the originality of true genius, devised a way for escape of the flood-waters of the lake by arranging that they should fall in a cascade over the entire length of the

dam, and so breaking up the descent that the impact of the falling water is nowhere allowed to have an injurious effect, but is guided and deflected in its course onwards and downwards with firm gentleness. He it was who noted and registered the expansion and contraction of the great mass of masonry, in such a way that even a passing cloud over the sun is duly recorded on the diagrams of automatic registration, and so contrived channels in the interior of the work that all water which might percolate through cracks was quickly collected and removed. Every step of this work, and subsequent great works which he built, was marked by the most careful scientific forethought and by sound practical supervision. The courage which enables such a man to take a step forward in advance of the current opinion of his time, knowing full well the tremendous issues involved, is one which must command our highest admiration. The surest proof of its success is the way in which his principles have since been copied-notably in the series of dams which, also in Wales, have made a number of artificial lakes for the supply of Birmingham.

In countries where the rainfall of the year is concentrated into a few months of a rainy season, where dry watercourses

II.

may in a few minutes be suddenly transformed into raging torrents, the peril of waters is of a nature of which we in

these fortunate Northern islands happily have little experience. To be cut off by these sudden torrents from food and shelter for an indefinite period is an experience by no means uncommon, and, to prevent such inconvenience, it is not unusual to take risks of very perilous nature.

Some years ago, when engaged in surveying for a railway among the mountains of the North-West Frontier of India, I started one morning in the month of April with two young English assistants to make a detailed survey of a difficult bit of country, where the railway had to pass, about ten miles from our temporary camp. The altitude was some 6000 feet above the sea-level, the winter snow had lain late that year, and the weather was cold and stormy. We reached our ground, however, without incident, passing in our way many dry water-courses. Late in the afternoon masses of heavy clouds began to gather, and the approach of a storm made us suspend operations, order our native chain-men and carriers to make for the nearest natural shelter, while we mounted and rode back towards our camp as fast as our horses could carry us. Soon the rain came in torrents, and as we galloped on, mile after mile, each successive water course we splashed through became a more formidable obstacle, until one, rather wider than the average, about a mile from our camp, was a broad rushing

river, quite unfordable. My steed, a clever well-bred mare, when urged into the rushing water, at once struck out bravely for the opposite bank, and we swam across together without parting company, but my companions were not so fortunate. Both were separated from their horses. One of the young men, a strong active swimmer, battled his way through the torrent without mishap, but the other got knocked over under his horse, and to my horror I saw his body being rolled over and over like a log in the foaming waves. Riding down to a bend in the stream, we endeavoured rescue him, but a friendly wave washed him on a sandbank, stunned and very blue about the lips, but otherwise, after a little while, not much the worse. But it was too close an approach to a serious disaster to be pleasant. Our small party of natives, poor fellows, tried to get back to camp rather than find shelter in some caves hard by, but they were held up by the floods, and had to spend the night shivering and hungry on the banks of a torrent, and one of their number succumbed to the exposure entirely.

to

There is, however, something intensely fascinating in the fight with water, whether in connection with the preventing of the effects of a flood, or building a bridge or a dam. The movement of the water, its unceasing flow and rise and fall, give it a living character, and make the game like that of the stalking of wild animals,

where ferocity or cunning has to be met by patience and skill, or the more exciting game of war, where the enemy is vigilant and crafty. Only, in the case of a river, there is the greater need of vigilance, in that the foe never sleeps, and may at any moment develop resources of force hitherto quite unexpected. Mr Rudyard Kipling, with that sympathetic insight into the lives of his countrymen in distant lands which is so characteristic of his writings, has depicted this anxious and arduous struggle in his "Bridge-Builders." The fact that often floods of unprecedented violence occur at most inconvenient times, not unnaturally has given rise to the idea among ignorant races that the river deity resents interference and control, and is determined to crush the daring mortals who attempt it. This, however, makes the ultimate triumph all the sweeter.

Some years ago, on one of the Indian frontier railways, at a time of acute national crisis, there was a very remarkable instance of this, a memorable experience to those who took part in it. Work had been going on during the cold season, from October to April, on the lower part of the line, where it left the plains of India and began the ascent into the mountain barrier along the Afghan frontier. At this place the difference between plain and hill is abrupt. A long stretch of desert separates the Indus from the hill region, and over this desert the rail

way had been made some years previously, the new line commencing at a native town some seven miles from the base of the hills. The hill region in this part of the country, and indeed for many miles along the frontier, consists of a series of ridges like the successive ramparts of a fortress, in which long slopes alternate with sharp precipices, resembling in general section the teeth of a saw. Athwart these ridges various rivers have forced their way, in gorges, which from time immemorial have formed the highways of communication between India, Afghanistan, and Central Asia generally. It was up one of these gorges that the railway was being made. The length of this particular gorge from the plain region to comparatively open country beyond was some fourteen miles, and of a width varying from a mile to a few hundred yards. The river, in ordinary times a stream in volume like the Dee or the Tweed, pursued 8 sinuous course down the gorge, at one time flowing in a deep pool along one precipitous side, and then crossing to a similar precipice on the other side. The line of the railway avoided the river crossings as much as possible, but with every desire to reduce bridge work it was not feasible to carry out the undertaking with fewer bridges than six in the fourteen-mile length, each bridge being from 150 to 300 yards in length. Of these six bridges, five came within a comparatively short

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