34-— THE ARTESIAN WELLS OF THE CAPE COLONY 

 By Bernard William Ritso. ^LI^•ST.C.E., F.G.S. 



TERMS USED.. 



As a doubt exists in the minds of many whether there is a differ- 

 ence or not between a bore, a boring, or a borehole, and an artesian 

 well, it is better at the outset to make this clear. 



From early times holes have been bored into the earth to tap 

 subterranean water confined, in porous strata, under sufficient hydros- 

 tatic pressure to rise to the surface, and as wells of this description 

 were tirst known in Europe in the French Province of Artois, the 

 term " artesian "' implied originally a boring from which water flowed 

 at the surface, or was spouted above it, like a fountain. In many 

 cases, however, the pressure was not sufficient to raise the water in 

 the borehole to the surface; still, the same term was applied to all 

 wells from which water could be conveniently pumped. To-day. 

 judging from current European literature, the term " artesian well " 

 is used to designate all vertical shafts of narrow dimensions put down 

 for the especial purpose of obtaining water, in contradistinction to the 

 expression '' well,'' which signifies a vertical shaft of much larger 

 diameter. The American terms " drilled-well " and '' dug-well " 

 express the meaning excellently, and are synonymous with the pre- 

 sent use of " artesian well '" and " well." 



SURFACE FEATURES. 



The geography and superficial features of this Colony, which 

 now includes Bechuanaland and the Transkeian Territories, are too 

 well known to require more than a passing remark. The land rises 

 from the sea towards the interior in a series of terraces, formed by 

 ranges of mountains, which, having comparativel}- little slope on the 

 landward side, constitute a succession of gigantic steps from the 

 coast to the Great Karroo, a plateau which can be described as a 

 part of the central tableland of South Africa. The position of the 

 coast plateau, of the Southern and Central Karroos lying between the 

 ranges of mountains and the Northern Karroo and Bechuanaland 

 beyond them, "as well as the situation of the Eastern slope and the 

 Transkei, are familiar. The relative heights of these plains have 

 been noticed by ever}one travelling from Cape Town by rail towards 

 the Orange River, but few people have become acquainted with the 

 geological structure of the country, upon which so' much depends 

 with regard to the existence and accessibilitv of underground sup- 

 plies of water, so that a brief sketch of it may assist in explaining some 

 of the allusions to geological data in connection with artesian wells 

 in this Colonv. 



