Discussion on the Proposed Channel Tunnel. 55 



of this proposal is, I hold, the fact that the feasibility of the 

 scheme could be tested by a section of the bridge being sub- 

 merged in any portion of the channel. If it fails, ^500,000 is 

 lost, less scrap ; but no such experiment can be made with the 

 proposed tunnel, and any failure there means the loss of the 

 money, and probably hundreds of lives as well. The next thing 

 in favour of the scheme is the rapidity of its construction. 

 Several naval architects have told me that they would be able 

 to construct the bridge in five years. Contrast that with the 

 ten or twenty years that would be required for the making of 

 any of the undersea tunnels, which Mr. Macassey admits are 

 very uncertain and risky undertakings. Now, structurally we 

 are as certain of the result with regard to the submerged 

 bridge as the engineers were of the Forth Bridge. The cost of 

 working one of these tunnels would be greater, the cost of ven- 

 tilation greater, and the pumping something extraordinary — 

 something beyond the powers of conception, or supposition. 

 Mr. Macassey said that the tunnel might be constructed in the 

 same way as the St. Clair one, but such a thing would be 

 impossible or practically prohibitive. You would require to 

 drive two tunnels, but the pressure would be too great to permit 

 of any such mode of construction. The tunnel-lining would 

 have to be from ten to twelve inches thick, and we can all 

 understand what a heavy cost the use of such material would 

 entail. The pressure of the water would be from three to four 

 hundred pounds to the square inch. In conclusion, as an 

 engineer I am practically opposed to the construction of tunnels 

 anywhere and in any way. I strongly object to them, and 

 engineers, from the experience they have derived, wherever 

 they can put up a bridge do so in preference to tunneling, and 

 we have the Forth and Tay Bridges as instances. It is only 

 because of insurmountable obstacles or strong opposition to a 

 bridge that induce engineers to drive a tunnel, as they know 

 that such an undertaking will be attended with many difficulties 

 and uncertainties. 



Mr. J. C. Bretland (City Surveyor) said : — I have lately 



