124 Sir Frederick Bramwell [May 19, 



maintenance of form, a material could be found which was practically 

 impermeable to water, I think it must be admitted that this would 

 be the stratification of all others which the engineer would seek, 

 had he the power of selection. But in most cases of tunnelling, still 

 more in the case of a Channel tunnel, the engineer is bound by 

 conditions which, except within very narrow limits, prevent him from 

 selecting his stratification ; he is comj)elled, as a rule, to take such 

 stratification as may occur. If this be true ordinarily of a line of 

 railway through the country, how much more is it true in the case 

 of a Channel tunnel ? Looking at the map, we see the Channel, 

 in its extent from the Lizard to the North Foreland, ranging in width 

 from 100 to 60 or 50 miles, excej)t in one place, but at that one 

 place, viz. for the short length between Boulogne and Calais on 

 the French side and Hythe and Dover on the English side, we find 

 the Channel reduced to a width of some 20 miles. Obviously, all 

 other things being equal, it is in this j^art, on account of its narrow- 

 ness, that the tunnel should be made, and there are further reasons 

 why this place should be chosen. — This narrower part has been 

 selected from the earliest times for the crossing from side to side, and 

 in that way the roads first, and the railways afterwards, have on the 

 two sides converged towards this part, and thus there exist already the 

 inland communications. As I have said, everything shows the desir- 

 ability of having the Channel tunnel in this narrow part. Then comes 

 the question, is it at this narrow part that the desirable stratification is 

 to be found ? Well, most fortunately we do find, as stated on the 

 highest geological authority, that there is, on the English shore 

 and on the French shore, the very formation of all others which is 

 desired. 



Every one knows that on the two sides of the strait there are 

 chalk clifis, and that this formation extends inland in both countries 

 for some distance. Chalk, we are well aware, is a material readily 

 cut, and when not exposed to the weather, is self-supporting. But, it 

 may be said, how about the water ? Is not the chalk the very form- 

 ation in which water is sought and from which it is obtained in such 

 quantities for the supply of towns ? and of myself it may be asked. 

 Are not you one of the engineers who some three or four years 

 ago suggested that so far as regards its potable water, London should 

 be supplied from the chalk ? How, therefore, can such a material 

 be one in which to make this tunnel ? Further : — it is well known 

 that on the beach in St. Margaret's Bay, and about there, the fresh 

 water wells up from the chalk in volumes. This is all perfectly 

 true, and if there were only one kind of chalk it would be an ex- 

 tremely pertinent criticism; but there is chalk and clicdk. Let me 

 ask you to look at the samples on the table and at the diagrams 

 before you. You will see there the white or ujDper chalk of which I 

 have just been s]3eaking, seamed with flints and loaded with water, 

 but you will also see depicted the lower chalk (grey chalk), or " craie 

 de Rouen," and the chalk marls. 



