1876,] «^7o [Lesley. 



The first division, owing to the loose and crumbling material of which it 

 is composed, requires some meclianical device to prevent it from slipping 

 or caving into the hole as it is drilled. Here the "conductor" is used A 

 "conductor" maybe simply a long box, without ends, made by spiking 

 together four planks 2" thick by 10" wide — a "woi)den conductor ; " or 

 it may be "drive pipe, " composed of a number of cast-iron cylinders joined 

 together and driven through the deposit ; or it may be what is now more 

 generally used, wrought-iron "surface casing," put in in a somewhat 

 similar manner. 



The "wooden conductor" can only be economically used where the sur- 

 face deposit is of inconsiderable depth, as a pit must be sunk to the rock 

 before it can be put in place. After the rock has been laid bare by the pick 

 and shovel, the " conductor" is securely set between it and the derrick floor, 

 the drill is let down to the rock through the conductor and the work of 

 boring commences. 



Where it is suspected that the floor of the Drift lies too deep to be reached 

 by digging, cast-iron "drive pipe" is used. This pipe is cast in sections 

 about 9' long. A space of 4" at each end is carefully turned in a lathe to 

 a certain gauge, and the end is cut smoothly at right angles to the axis of 

 the pipe, so that the joints will stand perpendicularly one upon the other. 

 A joint of pipe is placed on end in the centre of the derrick between two 

 "guides " which have been temporarily erected for the purpose of driving 

 it. A heavy " mall " working between these guides is raised and dropped 

 u]ion the pipe, slowly forcing it into the ground, precisely as piles are driven 

 for docks, bridges, &c. When the top of a joint has been driven to the 

 level of the derrick floor, a band of wrought-iron, made to fit the turned 

 ends of the pipes and heated red-hot, is quickly slipped upon the end of the 

 driven pipe and another joint at once set up. The contraction of this band 

 in cooling holds the two joints firmly together and the driving process then 

 goes on. In this way joint after joint is added and driven until solid rock 

 is reached. As many as 23 joints have been used in a well. Great care is 

 required w^hen so long a " string of pipe" is driven to keep it straight and 

 perpendicular, a broken band, or a large boulder encountered may cause 

 the pipe to so far deviate from the perpendicular as to necessitate the aban- 

 donment of the well. To avoid this the pipe should be frequently cleaned 

 out by the drill while being driven. 



The more common method now employed in driving the well shafts 

 through these thick accumulations of loose materials, is to use heavj^ 

 wrought-iron casing, made expressly for the purpose and armed with a 

 liardened collar or "shoe," at the bottom. This casing is made in joints 

 about 20' in length, which screw together in wrought-iron "thimbles," the 

 same as do ordinary gas pipes. The tube being thin and light as compared 

 with cast-iron drive pipe, cannot be so forcibly driven, but is worked down 

 carefully by drilling a hole the full size of its inside diameter, and always 

 keeping this hole open some feet in advance of the bottom of the pipe. In 



{Continued on page 378.) 



