Engineering Wonders of the World
Volume I

THE ARTESIAN WELLS OF AUSTRALIA. 317 A BORE AT CUNNAMULA THAT YIELDS 800,000 GALLONS PER DAY. let, since the water will continue to dissolve saline matter from the rocks or soil. It is reasonable to conclude, there- fore, that all artesian wells from which potable (drinkable) water is obtained must have leakage, either direct to the ocean or through valleys of denudation which have cut through the over-lying strata and exposed the porous beds. It follows, therefore, that these basins would be hydraulic and not hydrostatic.” Potability being the charac- teristic of the supply from the Australian bores, it would seem „ that Mr. Pitt- Hot Wells. . . man has the best of the argument. In reference to this question of the quality of the water, we may remark that flowing wells are sometimes due to the presence of gas, such as sulphuretted hydrogen or car- bonic acid, in the water under high pressure. When set free by a bore, the gas expands and forces the water above the surface in the same way as soda-water overflows a bottle when uncorked. Such a mineral water-spring is in operation at Baltimore, near the southern ex- tremity of the artesian area, the product, called the Zetz Spa water, being sold largely in Aus- tralia. The surface, or intake, as it is termed, the rainfall on which supplies all artesian water, is principally on the high levels of the coast range west of the artesian area, and includes nearly 70,000 square miles. Assuming the average annual rainfall to be 25 inches, and one-fifth, of it to sink through into the artesian area, it is estimated that 13,580 million gallons, much of which is lost by leakage, flows daily into the porous beds. As the last is in some places at great depth below the surface, the water rising in many bores has a very high temperature, the increase being estimated at about one degree Fahrenheit for every 44 feet of depth. The writer remembers bathing in A BORING OUTFIT AT WORK.