CRANE.| Prospecting and Boring for Mineral Waters. 105 
The drill part proper consists of several separate parts, and 
goes by the name of the string, or line of tools, and is about 
sixty-five feet in length. Beginning with the bit end, the parts 
are as follows: Bit, auger-stem, jars, sinker-bar, and rope- 
socket. A rope extends from the rope-socket to the bull-wheel, 
by way of the top or head sheave. The bit has several forms, 
which differ in shape with the purpose for which they are in- 
tended and the formation to be worked. There are two general 
forms, known as the cutter-bit, and the reamer. The cutter-bit 
is chisel-shaped, while the reamer is H-shaped, and is used to 
straighten up the hole from time to time. The auger-stem is 
a section of rod screwed to the bit to give sufficient weight for 
cutting. The jars are made up of two links, which slide one 
upon the other, and are fastened to the sinker-bar and auger- 
stem above and below. The object of the jars is to loosen the 
bit if it gets caught in the hole. The links slide one upon the 
other for a certain distance, thus allowing the upper part of the 
line of tools to acquire sufficient momentum to pick up the bit. 
Their action is especially useful in fissured ground, where the 
bit is liable to be caught by jamming in a fissure. The sinker- 
bar is also a section of rod, like the auger-stem, the purpose of 
which is to keep the rope taut. To the top of the sinker-bar is 
screwed the rope-socket, in which is inserted the rope. 
Method of Operation of Churn Drill.—When drilling begins the 
drill is lowered until the two parts of the jars meet; it is then 
raised until only four inches of clearance is left between links. 
The power-wheel is then turned until the pitman is at the top 
of the stroke; the walking-beam is then at the lowest part of 
its stroke. In this position the temper-screw is attached to the 
rope. From twenty to thirty feet of rope are then unwound by 
turning the bull-wheel, which loose rope is wound up in a 
large coil on the platform about the driller. 
Starting up the engine causes the walking-beam to move up 
and down, thus transmitting to the drill through the rope a 
chopping or reciprocating motion. As the hole is deepened the 
bit must be lowered, which is accomplished by unscrewing the 
temper-screw. The action of feeding also tends to turn the line 
