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TIDAL PHENOMENA AT INLAND BOEEHOLES NEAE 
CEADOCK. 
By Andrew Young, M.A., B.Sc, E.G.S., E.C.S. 
(Eead June 19, 1912.) 
(Plates III.-VI.) 
In the following pages the terms " artesian well," " subartesian well," 
and " potential level " are used in the following sense : — 
An artesian well is a bored well in which the water rises naturally to 
the surface of the ground and flows. 
A subartesian well is a bored well in which the water rises above the 
level at which it was first encountered to a level within pumping reach of 
the surface. 
The potential level of a well is the level at which the water stands 
when piped up as high as it will reach without recourse to pumps or 
siphons. 
An artesian well might thus be described as a well whose potential 
level is above the level of the ground surface, and it will be observed that 
I do not use the term " artesian " as implying any particular theory of 
the origin of the water pressure. 
During the last twenty years a large amount of boring for water has 
been carried on in the interior of Cape Colony. Very little was done in 
this direction previous to the year 1893. During the sixteen years, 1893 
to 1909, the Cape Government subsidised water-boring enterprise to an 
extent probably unparalleled elsewhere in the world. 
A very large Government water-boring establishment equipped with 
fifty to sixty drills of various types was gradually built up, and about half 
the cost of the work done was met by grants from the public exchequer. 
In connection with this expenditure of public money detailed records of 
most of the boreholes were carefully filed in the Government offices and 
generalised information based on these records was published in various 
Annual Eeports of the Government Departments concerned in the work. 
During the later years of the period mentioned the policy of the Govern- 
