[Originally published in Builder magazine; republished in Estates Gazette on 2 May 1870]
Mr Thomas Page, EC, has read a paper to the Society of Arts on his plan for a submarine tunnel across the British Channel.
He proposes to sink, between Dover or the South Foreland and Cape Gris-enz (17 3/4 nautical miles), eight conical wrought iron shafts, the longest about the height of Westminster Abbey towers; these shafts to be two miles apart, and consisting of an inner and an outer casing, the space between to be filled in with concrete after they are sunk and fixed or imbedded, and embanked also round with concrete to a height of 30 ft. on a base of 45 ft. all round. A network of moored chain cables would also help to secure them. Lighthouses would be placed on the tops of these shafts, at a height of 180 ft. above low-water mark.
"The shafts being in place, the bed of the sea would be brought to a fair surface by the operation of divers, who would be enabled to work without pressure on their lungs or their bodies; but into the particulars of this system (said Mr Page), I do not wish to enter, as it is a special arrangement for such purposes of operating in deep water.
"The next operation is that of sinking and bedding on the bed of the Channel, the tubes or construction for the railway. These may be for a single line or a double line. I will refer to the double line at present, and then describe a tube, the joint of which is patented by Mr. Williams, of Liverpool, by means of which the tube, moving on circular joints, can take an elastic position, and all the junctions can be made above the surface of the water, while the remainder of the tube is bedded in the sea.
"The space between the shafts being divided into lengths, say of a quarter of a mile each, and heavy iron frames fixed in the bed of the Channel by the divers, the lengths of tubular sections which I would proposeto submerge at one time are 1/4 mile, 1,320 ft, a little more than the length of Waterloo Bridge. Eight of these lengths being sunk, and covered, complete the distance of two miles, and if a sufficient power and a sufficient number of operators were provided to commence from each shaft, the whole between two shafts would be done in half the time; and it is equally certain also that nine times the power and operators would complete the whole distance between Dover and Cape Gris-nez in the same time as would be required for joining two shafts.
"The gigantic nature of the work and the magnitude of its details require corresponding means of execution, both in the steamships and other vessels, for placing the shafts in position, and for embedding the lengths of tube in their proper places in the bed of the Channel, as well as for all the operations for filling the spaces between the outer and inner rings of the shafts with concrete, in forming the banks of concrete round the shafts, and in covering with concrete the submerged tubes immediately they are placed in position. It is by an excess of power and means, in steamships and other vessels, in operators, and in materials for forming concrete, that the progress and completion of the work can be accomplished with rapidity and economy. Thus to cover a length of tubular section a quarter of mile long, in two hours of the tide, would require 1,500 men; to fill the space between the rings of each conical shaft would require 500 men for two hours' work; and to form the bank of concrete round each shaft would require 350 men for the same time."
The cost seems to have been estimated at £8,000,000; or rather Mr Page's plan was devised on an understanding with Mr Newman, of the firm of Freshfield and Newman, that if he could stake his professional reputation on a plan that could be completed for £8,000,000, there would be no difficulty in providing the funds for its execution.
In the discussion which followed the reading of the paper, opinions were expressed pro and con as to the practicability of the scheme. Mr Brassey was among the speakers. He said that so far as he had been able to understand the project, it was one of such a gigantic and exceptional character as he had never before heard propounded. No engineer had ever attempted anything of the kind, and he very much doubted whether it would succeed; his impression was that it would not. He did not think it was possible to sink the tube, as was proposed, to the depth of some 200ft by any means yet known; and to attempt to do a thing so gigantic without greater experience would be a very hazardous experiment, to say the least of it. He agreed with Mr Bateman (who had previously spoken) that it was impossible for divers to work at a depth of 200ft. Therefore, with no experience to guide them, he thought it was a bold matter to attempt to execute such a project, and no wise man would attempt it.
Mr Page said Mr Brassey's objection as to divers working 200ft below the sea without undue pressure upon their lungs and bodies, was very easily answered. Supposing the room in which they then were was at the bottom of the sea, and the walls were carried up above high water, would any one dispute that they could send out a diver from that room into the sea, passing through a sort of valve-cupboard into the sea, and give him only the atmospheric pressure, with perhaps a pound or so more. He had devised a dress for this purpose, by which all pressure was removed from the body. That being explained, all the difficulty about divers operating in deep water was removed. As to want of experience, all great engineering feats had been carried out without previous experience.
