SUBMARINE TUN N KL1N<; 217 



nent lining the cast-iron rings were to be introduced instead 

 of brickwork, as heretofore. A start was made on Aug. 7 to 

 drive the heading into the soft matt-rial, but two days later, after 

 the work had been advanced C ft. into the soft vein, ordeis 

 were received to suspend all work on account of the great 

 financial depression of the time. This was unfoitunate ; and 

 could it have been anticipated a few days the heading into the 

 soft material would have been left unopened. As it \\as now, 

 from being first disturbed and then abandoned, the water was 

 first allowed to soften up the black mud in the heading, and, in 

 ppite of the bulkhead, a considerable quantity of the material 

 was washed into the tunnel. 



This stay of proceedings was utilized by making a horizon- 

 tal test boring in the heading on the Long Island side. At 

 this shaft no work had l>een done since the departure of the 

 contractors, beyond the building of a brick bulkhead and air- 

 lock in the tunnel. Compressed air had then been put on, 

 which considerably reduced the amount of water flowing into 

 the tunnel from the heading. The action of the coinpr- 

 air had l>een somewhat jM-culiar: for notwithstanding the great 

 depth of the tunnel l>elow the river bed, at 10 Ibs. pressure the 

 air l>egan to escape through the heading, and with a pressure 

 of 35 Ibs. per sq. in. small bubbles of escaping air could l>e 

 seen rising to the surface for over 300 ft. up and down the 

 river. This seemed to indicate that the ground above the 

 tunnel had l>een honeycombed up to the river bottom by 

 tin- previous washing-in of such quantities of the soft green 

 chlorite. As it was known that there were detached lumps of 

 rocks in this soft vein, 'J-in. heavy pipe was used for the test 

 boring, \\ith drive-well couplings, and a circular, hollow steel 

 bit for the cutting end. This pij>e was driven in the same way 

 as the one on the New York side, and after passing through 

 chlorite and various kinds of soft-rock fragments, solid rock 

 was a_ram met at 32 ft. Into this rock a hole was drilled to n 

 depth of .V4 ft., using a small bit on the end of a 1-in. pipe aw 1 



