108 University Geological Survey of Kansas. 
piston-rod is attached the piston. The other end of the rod is 
fastened to the drive-head. The drive-head is provided with 
two sets of ball bearings, between which is a flanged collar se- 
curely fastened to the drive-rod. Any movement of the piston, 
caused by forcing water into one end of the cylinder and allow- 
ing it to escape from the other, will produce a similar movement 
in the drive-rod. Below the cylinder the drive-rod is provided 
with a clamp-head or chuck, by means of which it can be se- 
curely fastened to the drill-rod proper, Any movement of the 
piston will then be transmitted at once to the drill-rod. 
The feed is extremely sensitive and easily regulated, as it de- 
pends entirely upon the amount of water that is fed to the cyl- 
inder. The cylinder is fed by a force-pump. The feed may be 
employed not only in forcing the drill downwards against the 
bottom of the hole but also in lifting the rod. The rod may 
also be lifted by cable, which winds upon the drum driven by 
the actuating mechanism of the drill, and passes over the 
sheave placed on the derrick top erected above the drill. The 
upper section of the rod is provided with a flexible ball-bearing 
jetting connection, by which, through a hose, water is brought 
to and forced down the rod to the bottom of the hole, thence 
rising upwards bears with it the cuttings and sludge produced 
by the action of the drill on the formation worked. 
There is another method of feeding, namely, the ‘‘differential- 
screw feed,’’ which is employed mainly on the smaller ma- 
chines, such as are used for comparatively shallow holes and 
underground work. 
The hydraulic feed is especially adapted to large-sized and 
deep wells. Itis heavy and, therefore, less convenient to move, 
but, due to the ease and rapidity of change of the feed, it is 
growing in favor. 
The rod is a strong iron or steel tube, with a small-sized hole 
to furnish free passage for the water to the bottom of the hole, 
and to allow a return current outside the rod and between the 
rod and the hole. 
The essential parts of the drill proper are at the bottom or 
lower end of the rod, and are, in the order in which they occur, 
