on the locomotive system. (6). In 1871 Mr. Remington, in a letter to the "Times" re-stated the reasons which had long before led him to disapprove of tunnelling through the sub-sea chalk. The recent finishing of the Mont Cenis Tunnel seems to him to be a favourable augury for a Channel tunnel; but he advised caution in selecting the geological stratum to be pierced. At a depth of 100 feet below the sea-bed he believed there was a thick stratum of clay, free from and impervious to water. He found that, in mid-channel, the chalk of the sea-bed is quite bare of any plastic covering that could resist a formidable pressure of sea-water. He advocated a narrow tunnel, for a single line of rails, with bays or sidings for the passage of trains; a second tunnel, if wanted, might afterwards be made by the side of the first. The Varne, or some other shoal in mid-channel, might be selected as the site for a ventilating shaft. The spoil from the tunnel might be utilized to reclaim much of Romney Marsh, behind Dungeness. (7). M. Lesseps, the celebrated engineer of the Suez Canal, announced in 1875 his belief in the soundness of the chalk stratum for the Channel tunnel. He would go 160 feet below the sea-bed, and would ventilate by means of land shafts at the two ends of the tunnel. Other projects, started within the last few years by Mr. Mayer, Mr. Dunn, Mr. Sankey, Mr. Boyd, &c., may be passed here without comment, as presenting no special characteristics.

The Anglo-French Government Scheme.-We have thus cleared the ground for a consideration of that particular Channel-scheme which is at present occupying more attention than any other, partly because the Governments of the two countries are negotiating on the subject. The Paris Exhibition of 1867 was the means of drawing public attention strongly to the matter. M. Thomé de Gamond exhibited a model of the tunnel and works proposed by him; and although his stupendous cones, immersed in a vast depth of water, gave a tinge of extravagance to the whole affair, his model induced other engineers to interchange views. Sir John Hawkshaw had, two or three years earlier, pronounced in favour of a tunnel through the chalk. Geologists have shown that England was once joined to the Continent, the insular separation having been effected by irruptions of the sea; chalk is known to exist to a great depth on both coasts, and it is inferred that there is an unbroken connexion in chalk under the soil of the sea-bed. Sir John made careful geological examinations of both coasts, and then, in conjunction with Mr. Brassey and Mr. Wythes, caused borings to be sunk on each coast. There resulted a plan for a Channel tunnel, starting from St. Margaret's Bay, four miles east of Dover, and ending three miles west of Calais, between that town and Sangatte. The three engineers dispensed with shafts and all other works in the sea, proposing to excavate the tunnel from the two ends only, and afterwards to ventilate it by air-pumping apparatus. At a depth of two hundred feet below the sea-bed it was considered that infiltration of water into the chalk would be almost impossible.

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After various discussions in 1868, an Anglo-French Committee took up the subject in 1869, and prepared a scheme for submission to the Board of Trade. The Emperor Napoleon III at the same time appointed a French Commission to investigate and report; the Commissioners pronounced in favour of a tunnel through the chalk, but could come to no decision as to the length of time or the amount of capital that would be needed. They recommended, as a preliminary measure, that the two Governments should cause two driftways to be made under the sea-bed as a means of ascertaining practically the nature of the stratification. The disastrous Franco-German war in 1870-71 put a sudden stop to these Channel discussions, and France was too overladen with financial obligations to enable her to do much in the matter in 1872. At length, in 1873, negotiations assumed a new aspect. A few projectors formed a Channel Tunnel Company," and two Committees were appointed to organize a scheme. Lord Richard Grosvenor, Mr. William Hawes, Admiral Elliot, Mr. Brassey, Sir John Hawkshaw, and Mr. Brunlees on the one side; M. Michel Chevallier, M. Talabot, M. Thomé de Gamond, &c., on the other. The politicians and commercial men discussed the terms of possible agreements with the two Governments; while the engineers resolved to commence a shaft and a short driftway on each shore as an experimental precaution. The various Chambers of Commerce in France, in towns anywhere near the French end of the tunnel, were consulted, as were the Prefects and Councils of the Departments, and the authorities of Calais and Boulogne; the Railway Companies, too, of northern France and of south-eastern England were taken into council, and the English Government were invited by the French Government to participate in the great work. Baron Rothschild, M. Léon Say, and M. Michel Chevallier formed a syndicate to discuss matters of finance, subsidy, concession, &c., and to find the means for defraying the cost of preliminary borings, driftways, &c.; M. Lavalley was joined with them as engineering adviser. Thus passed 1873 and 1874.

In 1875 the Syndicate of Concessionaires agreed with the Prefect of the Pas de Calais concerning the tariff of charges for passing through the tunnel, if and when completed; it was resolved to be about fivefold the average charge of French railways per mile. A Bill was brought into the Chamber of Deputies to give legislative sanction to the scheme, and this became law after passing through its various stages. The English and French Governments appointed a joint Commission to examine and report on the international features of the whole scheme. The English members were Captain Tyler, of the Board of Trade, Mr. Kennedy and Mr. Austin Lee, of the Foreign Office, and Mr. Horace Walton, of the Department of Woods and Forests; the French members were M. Gavard, M. Kleitz, M. Lapparent, and M. de Lafaulotte.

The report of these joint Commissioners, published in the summer of 1876, is so surrounded with conditions, provisoes, and

precautions against possible contingencies, that the net result is calculated somewhat to damp the enthusiasm of those who imagined that a grand international work is to be commenced forthwith, and pushed on to a successful conclusion by the joint forces of the two nations. The Commissioners, after holding many meetings at Paris and in London, agreed on a series of resolutions to be presented to the two Governments, and to form the basis of a Treaty to be hereafter negotiated, which Treaty itself will require to be ratified by the respective legislatures-a long double process which will go far to exhaust the year 1877. The following are the chief headings of the recommendations stated as concisely as possible. The boundary between the two countries (in regard to this tunnel) shall be midway between low water on the English side and low water on the French side. Each country is to construct its own half of the tunnel, in conformity with English and French decrees, orders, and statutes respectively. The tunnel, with its rails, is to be placed in connection with the existing English and French railways. By or before the month of August, 1880, the French Company and an English Company are to negotiate and sign an agreement concerning the construction, maintenance, and working of the tunnel and its accessories. An International Commission of six persons shall be appointed to be the medium of communication between the two Governments and the two Companies respectively. These Commissioners are to be permanent inspectors, advisers, and arbitrators, and are to keep the two Governments well informed on all matters relating to the great undertaking; and they will submit to the Governments any proposed Supplementary Conventions touching the construction and working of the line. A tariff of maximum fares and rates will be set forth officially. Each Company is to keep its own half of the tunnel in repair, under stringent obligations. The Governments are to grant a concession of 99 years to the Companies; at the end of that period the rights of the Companies will cease, and the two halves of the tunnel will become national property, English and French respectively. The tunnel is, at this date, to be surrendered in good condition, and the rolling stock, plant, stores, &c., to be taken at a valuation. Preliminary works of exploration are to be commenced before July, 1877, and the Companies or Concessionaires, if not satisfied with the results of the borings, or if influenced by any other circumstances, may abandon the whole undertaking any time before August, 1880, or before August, 1883 by special agreement. If the Companies, after the trial borings, &c., decide to retain the concession and to proceed with the undertaking, they are to be allowed twenty years from that date for constructing and finishing the tunnel and works. (Thus the opening of the tunnel for traffic may be delayed till the year 1903). The Concession may be forfeited under circumstances provided for in the official documents, or the Companies may surrender it on showing their inability to finish the works. If the works are finished and opened for traffic, at the end of thirty

years thereafter the two Governments may purchase them in their entirety, at an annuity-price depending on the ascertained net profits, the annuity to be payable until the end of the 99 years concession. The breaking out of war between England and France, or any suspension of friendly relations that might make the tunnel-railway a source of danger to one or both, is provided for in a very sweeping way. Each Government may stop the works or the passage through its own half of the tunnel, or damage or destroy the works, or flood the tunnel with water. This it may do without consulting the wishes of the other Government; but a basis is laid down on which compensation to the Companies is to be estimated.

It will be seen, then, that the two Governments must frame and sign a treaty, and that this treaty must be ratified by the two legislatures, before the Tunnel Company can know what is to be its future position in regard to the two nations. Moreover, the Company really consists at present of only a few projectors; there is no large body of shareholders; there is no fund except a few voluntary subscriptions; and as no one knows whether the total cost will be five millions or ten millions sterling, no scheme for raising the necessary capital has yet been put in operation. The South Eastern, the Chatham and Dover, and the Northern of France Railway Companies have subscribed towards the fund` for making the experimental driftways; the remainder having been contributed by various persons and public bodies. These experimental works are at the present time in progress. Should nothing occur to necessitate a change of plan, the tunnel will commence at St. Margaret's Bay, and will proceed by a descending gradient of 1 in 80 for about three miles.; from thence to the centre of the Channel will be on the slight gradient of 1 in 2,640; and the ascent to the French shore will be somewhat similar. Below the rails in the tunnel will be the necessary drains, with pumping stations at the two shores; pipes for ? ventilation, pierced with air-holes, will run along the two sides. Loop lines will connect the mouths of the tunnel with the existing railways. A tunnelling machine, invented by Mr. Dickenson Brunton, is to be used; it is said to cut through grey chalk at the rate of a yard per hour. The machine cuts away the chalk in vertical slices, which break up, fall upon an endless band, and are conveyed out to the mouth of the tunnel. With two machines working from the two ends, the engineers believe that a driftway could be pierced in two years, and that an enlargement of this driftway would form the tunnel itself.

Mr. Prestwich, in a paper read before the Institute of Civil Engineers, discusses the geology of the Channel district, and believes that the chalk will be safe for tunnelling, but anticipates extreme difficulty in conducting the operations. To many engineers the problem of ventilating the tunnel presents more difficulties than that of constructing it. If (some of them urge) locomotives and fuel be used for working the trains, and if there are several trains per day the air must be renewed every hour

to preserve it in a sufficiently pure state; and this renewal would cause a current of twenty miles an hour towards one end or the other. No such difficulty has ever before presented itself in practical engineering. The Mont Cenis Tunnel, by far the longest in the world at present, is only one-third as long as the Channel Tunnel will be, and is, moreover, much better suited for ventilation. The Metropolitan Underground Railway, though pierced with numerous openings for stations, light, and ventilation, is nevertheless filled all day long with very impure air. Even if absolutely smokeless fuel were used, the sulphurous and other gaseous fumes would unavoidably vitiate the air of a tunnel twenty miles or more in length.

The Baron M. M. von Weber, a German engineer, has suggested reasons for doubt whether, even if constructed, the Channel Tunnel would ever pay more than a trifling interest on the heavy outlay. Supposing that 300,000 passengers cross yearly between the four ports so often named, and this number be multiplied sevenfold by the tunnel facilities, there would still be only a small margin of profit at the present rate of steamboat fares; while if that rate were much raised, the increase of number would be checked. Goods' traffic must be counted on to supplement the gross receipts. This traffic would only be such as can afford to pay a high-speed rate of freight; the heavier and bulky articles-coals, rails, iron manufactures, machinery, cotton goods, &c.-would probably still continue to go by sea to the several Continental ports. Another consideration offered by him bears relation to the trucks or waggons in which the goods are packed. If the traffic were to become at all considerable, more English waggons would be wanted to traverse the Continent than foreign waggons to traverse England; seeing that our exports of bulky and ponderous articles are so much greater than our imports, so far as concerns the Continent of Europe. Thus would be required a large increase in the working plant of the English Companies, involving a certain outlay for an uncertain profit. Then again, English railway waggons are nearly always lower and shorter than foreign, and have points of difference in their construction which would render it difficult for the two kinds to be linked together in the same train. Not two kinds merely, for the waggons of France differ from those of Belgium, Germany, and Italy, as well as from those of England. Moreover, the legislatures and governments of the Continent insist on regulations which are not in force in England; insomuch that through traffic in merchandize would encounter obstacles of which we know nothing-rendering the invaluable "Clearing House" system, which so much facilitates traffic within our own insular limits-almost inapplicable. The rolling stock accounts and the through traffic accounts would alike become complicated and unsatisfactory. The Baron sums up with the sarcastic remark that "The Tunnel project arose from fear of sea-sickness, and is therefore literally a sickly one."

G. DODD.