THE CHANNEL TUNNEL. 405 



between Folkestone and Dover, of which so mucli has been said. All the 

 geological work was done in the years 1865-7 ; the machine was tested 

 in 1870.^ Moreover, this same Channel Tunnel Company originated the 

 French Company, and supplied the plans on which their concession was 

 obtained in 1875. Investigations which have since been made have con- 

 firmed the results of these earlier inquiries, but have added no new facts 

 of much importance from an engineering point of view. 



Having given so much of the history of this Company as seemed 

 necessary, I will now proceed to the general question of the tunnel. 



I shall pass by the political, and, in great part, the military side of the 

 question — but the latter cannot be overlooked by the civil engineer, as 

 the terminal point of the tunnel will, in this country, have to be deter- 

 mined by military considerations. 



Primarily, the Channel Tnnnel question is a geological one. A know- 

 ledge of the geological conditions of the ground to be passed through is 

 absolutely necessary for the successful execution of a tunnel under the 

 Channel. 



Monsieur Thome de Gamond was the first engineer who worked at the 

 geological part of the question. With admirable energy and perseverance 

 he devoted much time to the study of the geology of England and France, 

 not confining his labours to the coast line, but continuing them inland. 

 Unfortunately he failed to realise the insuperable difiBculties of making a 

 tunnel under the Channel through the formations below the chalk. The 

 result of his labours was the proposal to make a tunnel under the Varne 

 from Folkestone to Cape Grisnez, through the Wealden and Oolitic for- 

 mations. Monsieur Thome de Gamond had not neglected to consider the 

 possibility of making a tunnel through the chalk further to the east. 

 He was led to select the line under the Varne, in the belief that, by 

 sinking a shaft on the Varne, the tunnel could be attacked at four points 

 instead of two, and so the work could be more quickly done. In this, I 

 think, most engineers will now agree he was mistaken, and that a tnnnel 

 is not practicable on the line which he adopted. In later years M. Thome 

 de Gamond was associated with those who proposed a tunnel through the 

 chalk, and he signed the plans for such a tunnel, on which the French 

 concession was obtained in 1875. It was in the year 186G that he pi'o- 

 posed a tunnel under the Varne. 



For some years before this time. Sir John Hawkshaw had been con- 

 sidering the practicability of a tunnel under the Channel. His large 

 experience in tunnelling led him to see the facilities which the chalk 

 would offer for making such a tunnel. Early in 1865 he obtained the 

 services of Mr. Hartsinck Day, an accomplished geologist, who possessed a 

 knowledge of surveying. Mr. Day spent several months in that year in 

 examining and surveying the cretaceous and underlying beds on the Eng- 



Ilish and French coasts, and prepared for him a geological map, showing 

 the position of those beds along the two coasts. He, moreover, made a 

 conjecture as to their position on the bed of the intervening sea. This 

 survey confirmed the fact — in so far as it was then known from the writings 

 of W. Philips, De la Beche, and others — that the chalk strata overlying the 

 gault are almost identical, bed for bed, on the two coasts. 

 : 



' Trials were made with Mr. Brimton's machine in the grey chalk at Snodlancl on 

 many occasions. On the 8th September, 1870, it excavated aheading 7 feet in diameter 

 at the rate of 44 inches per hour ; on the 20th January, 1871, the rate was 45 inches an 

 hour, and on the 25th February, 1871, it was 49 inches an hour. 



