1006.] on Ore Deposits and their Distribution in Depth. 315 



regions were regarded as maintained by the rainfall on the distant 

 hills, as when the flowing wells of lower Egypt were held to be 

 nourished from the mountains of Darfur, and those of Central 

 Australia by the rains on the distant Queensland Hills. 



2. That water could descend by capillary action to great depths, 

 even against high internal pressure, was maintained on the basis of 

 an experiment by Daubree. He inverted a vessel of water over a 

 slab of porous rock, forming the roof of a cistern filled with high 

 pressure steam. The water percolated downward in spite of the 

 upward pressure of the steam ; and hence it was claimed that 

 capillarity could suck water downward against the resistance due to 

 the earth's internal heat. But this experiment, as shown by Fisher 

 and Kemp, proves nothing, as the movement was toward a free air 

 space, and there is no free air space in the earth, corresponding to 

 the cistern in Daubree's experiment. 



3. The third argument for the descent of the surface waters to 

 great depths is based on the hydrodynamic principle, invoked by 

 Van Hise, that a current of water will use the whole area of any 

 channel open to it. If a stream of water be allowed to enter a deep 

 trough, the current does not flow in a straight line from the point of 

 inflow to the exit, but it slowly spreads downwards and upwards till 

 the whole of the w^ater in the trough takes part in the movement. 

 Similarly, according to Van Hise, water percolating downwards at one 

 place and re-discharged elsewhere in springs or wells is not confined 

 to the direct line between the two places, but it spreads sideways 

 through a great width of country and sinks downwards to the greatest 

 available depth. Hence, meteoric water should be universally dif- 

 fused through a zone at a shallow depth below the surface. According 

 to this conception the whole of one zone of the earth's crust is satu- 

 rated by a great subterranean sea ; and as its waters would be super- 

 heated, they would have great solvent powers, and being universally 

 diffused, they would come in contact with all the metallic grains that 

 may occur scattered through this zone of the earth's crust. 



But the universal existence of this subterranean sea, seems to be 

 abundantly disproved by the evidence of many deep mines and wells. 

 In Bendigo, e.g., the ground water is confined to the surface zone, 

 below which the rocks are dry, except where the levels happen to tap 

 a spring of hot alkaline waters, which are probably of plutonic and 

 not of meteoric origin. They are waters given off from the cooling 

 magma of the earth, and belong to the same category as the fluids that, 

 scattered in innumerable microscopic cavities, give quartz its milky 

 whiteness and form the vast steam clouds, when, through a volcano, 

 molten rocks reach the surface of the earth. These hot waters are, 

 therefore, sometimes called magmatic on account of their origin from 

 the rock magma of the interior, or juvenile, by Professor Suess, as 

 they are making their first appearance on the earth's surface, or 

 plutonic from their deep-seated origin. 



