THE GREAT ALPINE TUNNELS.'' 



By Francis Fox, Esq., M. Inst. C. E., M. R. L 



The subject for this ev^ening-'s discourse is that of the three great 

 tunnels through the Alps, viz, the Mont Cenis, the St. Gothard, and 

 that which is now in course of construction — the Simplon. 



But before dealing with the details of these particular works it will 

 be desirable to considei- what tunneling is, and also some of the more 

 remarkable instances of it in bygone days. 



One great drawback in connection with the subject — so far as a dis- 

 course is concerned — is its unsiiitability for the photographic art. 

 Unlike a battle ship, or a splendid bridge, or a grand block of build- 

 ings, which can be made into line views and pictures, the work of the 

 mole is hardly adapted to the sensitive plate. I therefore propose to 

 make use of the '" language of the pencil,'' and to make a few rough 

 sketches on the blackboard. By these means 1 trust 1 may be able to 

 explain some of the difficulties which have to be encountered, and also 

 show how a tunnel is constructed. The child's detinition of drawing, 

 "first you think and then you draw a line round your think,'' will 

 come to our aid. 



The art of tunneling dates back to very remote ages, and there are 

 records of such works which were constructed five hundred to six hun- 

 dred years before the Christian era. 



An interesting account is given by one of your most distinguished 

 members, in an article in the Encyclopaedia Britannica, of the tunnel 

 under the River Euphrates, at Babylon. This city, similar in some 

 respects to London, lay half on one side and half on the other side of 

 the river. High walls, penetrated by occasional gates, surrounded the 

 city and lined each of the banks of the river. These gates (of which 

 a pair of the great hinges can be seen in the British IVIuseum) were 

 closed at night and during war; and a tunnel was constructed below 

 the bed of the river by means of what is technically known as the 

 "cut-and-cover" s^'stem. In those days the Greathead shield was 

 unknown, and consequently the river had to be diverted so that the 

 excavation could be made in the dry bed and cut open to daylight, the 



"Reprinted from Proceedings of the Royal Institution of Great Britain, Vol. XVI, 

 Part I, 1901. Read at weekly evening meeting, Friday, May 25, 1900, His Grace the 

 Duke of Northumberland, K. G., F. S. A., president, in the chair. 



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