102 University Geological Survey of Kansas. 
porous beds, together with the amount of rainfall in the district 
in which they outcrop, will give us sufficient data for calcula- 
tion. 
In the case of prospecting for water, the opening made is em- 
ployed in extracting the water, 2. e., the prospect hole is a fin- 
ished well. 
DRILLS AND DRILLING. 
Drills.— Prospecting and drilling are accomplished by means 
of,drills, of which there are three kinds, namely: The churn, 
the diamond, and the calyx. 
The Churn drill is a modification of the rod method of drill- 
ing largely employed in Europe. As used at the present time, 
in the United States, it goes by the name of the ozl-well or cable- 
tool system. Of the class there are a large number of forms, 
some self-contained, that is, mounted on trucks, being complete 
in themselves; while others have the derrick and power parts 
separate, constituting the so-called carpenter's rig and engine. 
(Plate VII.) 
' The Diamond drills have largely superseded the older methods 
of drilling in recent years, due to the ease and rapidity of drill- 
ing, and mainly on account of producing a complete record of 
strata passed through. (Plate VIII.) 
The Davis-Calyx drill is a comparatively recent production, 
but has proven itself so efficient and has surmounted so many 
obstacles, which even precluded the use of the diamond drill, 
that it has come quickly into favor. (Plate IX.) 
A complete record is also obtainable by this drill. The cut- 
ting is done, not by diamonds, but by steel teeth and chilled 
shot. 
Description of the Churn Drills.—The apparatus for the oil- 
well or so-called churn drill consists of a derrick ranging from 
fifty to seventy-five feet in height, which is built up of heavy 
timbers, or better still of planks, so placed as to produce an 
angle-construction for the corner posts. The corner posts are 
given a batter of an inch or so to the foot, and are held in po- 
sition by horizontal cross-girders, and are still further strength- 
