SUBMARINE TUNNELING 201 



CHAPTER XVIII. 



SUBMARINE TUNNELING: GENERAL DISCUS- 

 SION. THE SEVERN TUNNEL. 



GENERAL DISCUSSION. 



SUBMARINE tunnels, or tunnels excavated under the beds of 

 rivers, lakes, etc., have been constructed in large numbers 

 during the last quarter of a century, and the projects for such 

 tunnels, which have not yet been carried to completion, are 

 still more numerous. Among the more notable completed 

 works of this character may be noted the tunnel under the 

 River Severn and those under the River Thames in England, 

 the one under the River Seine in France, that under the 

 St. Clair River for railway, that under the East River for gas 

 mains, that under Dorchester Bay, Boston, for sewage, and 

 those under Lakes Michigan and Erie for the water supply of 

 Chicago and Cleveland in America. Among the partly com- 

 pleted submarine tunnels which have been abandoned the most 

 notable example is, perhaps, the Hudson River tunnel. For 

 the details of the various projected submarine tunnels of note, 

 which include tunnels under the English and Irish Channels, 

 iinilcr the Straits of Gibraltar, under the sound between 

 Copenhagen in Denmark and Malino in Sweden, under the 

 Messina Straits lietween Italy and Sicily, and under the Straits 

 of Northuml>erland between New Brunswick and Prince 

 I-M ward Island, the reader is referred to the periodical litera- 

 ture of the last few years. 



Previous to attempting the driving of a submarine tunnel 

 it is necessary to ascertain the character of the material it will 



