LXXVI. 



NOTES ON HYDRAULIC BORING APPARATUS. 



It is better to buy good artesian well tubing than to use a 

 cheap gas piping or boiler tubes. Not only is the artesian tubing 

 straight, and of even diameter, but it is free from knobs and is 

 fairly homogeneous in structure ; but such cannot certainly be 

 said even of the best gas pipe. The price of the best 4 in. 

 Russian artesian well tubing in Sydney is 2s. 2d. per foot, gas 

 pipe of the same size is Is. 2d. per foot, and boiler tubing Is. Id. 

 per foot. 



i MPROVEO BALL UNDER-REAMER- 

 JAWS OFEM — JAWS CLOSED — 



— i SCALg — ( 



fic - 2 '■"'" 



.ML JL 



■ S./-J 

 I 1 



: - 





Fig. 2. 



At the bottom of the tube is a hardened steel cutter to with- 

 stand the driving through hard material. 



When the tube is lowered to the bottom, the flexible hose from 

 the pump is connected to the top, as shown in Fig 1, and the 

 pump started. The tubes are then lowered as fast as the mud 



