658 



HISTORY OF THE SEA. 



nf continuous action under the trying requirements of the 

 rough work at Hell Gate. A striking drill was then tried, and 

 a machine was built and put in poskion, but the very day it 

 was to commence to work it was run against by one of the 

 craft so constantly crowding through Hell Gate, and destroyed. 

 M r. Shelbourne then retired from any further attempt, and the 

 Government has undertaken it, and placed the management of 

 the operations in the hands of General Newton. 



The plan now 

 undertaken is to 

 undermine the 

 whole bed of the 

 river at this point, 

 with a series of 

 galleries connected 

 by transverse gal- 

 leries, leaving only 

 so much rock standing in columns as 

 shall insure stability to the roof above. 

 When this work is completed, those sub- 

 marine channels are to be charged with 

 the requisite number of thousands of 

 pounds of nitre-glycerine, and blown 

 up with one grand explosion. This 

 enormous work is now well under way, 

 and is being rapidly pushed to comple 

 tion. Work is carried on day and night, three sets 

 of workmen being engaged in it, each working eight hours 

 The drilling has thus far been done chiefly by hand, and is 

 very laborious. The workmen are chiefly Cornish miners, who 

 aione can stand the severity of such mining. They are hardlv 

 ever dry while at work, and in the winter their clothes are fre- 

 quently stiffened by ice. Preparations are however making to 

 as« machine drills operated bv compressed air 



MUSHROOM DRILL. 



