OBSERVATIONS ON THE DAUBREE EXPERIMENT 15 



into a magma (presuming for the moment that it is possible) at 

 this rate would be very little likely to produce any very violent 

 effects. 



The foregoing statements, of course, by no means imply that 

 water cannot, and does not, penetrate, by capillary action or other- 

 wise, to a considerable depth into the upper and cooler layers of the 

 crust of the earth. Indeed the preceding figures and arguments 

 tend to show that water would be likely to occur in appreciable 

 quantities down to depths of about 500 meters (1,500 feet) and in 

 minute quantities down to perhaps 1,500 meters (5,000 feet) — a 

 conclusion which is, we believe, entirely borne out by experience. 



CONCLUSION 



The Daubree experiment on the passage of water through a 

 disk of sandstone against a certain counter pressure of steam is, 

 as has indeed been pointed out by others, an example of the effects 

 producible by capillarity. The same effect may be obtained, and 

 much more simply, by atmometer experiments such as we describe. 

 The magnitude of the possible effect under various conditions may 

 therefore be deduced from the laws of capillarity. Capillary forces 

 are effective only when there is a surface of separation within the 

 pores; moreover they diminish steadily with rise of temperature, 

 and vanish at the critical point of the liquid. Calculation shows 

 that the effects producible at any considerable depth are, in com- 

 parison with the pressure due to the hydrostatic column, insig- 

 nificant except in pores of such fineness that the amount of water 

 which could flow through them is infinitesimal. 



It appears therefore as if the probabilities were all against the 

 notion that appreciable amounts of meteoric water can ever pene- 

 trate into deep-seated and highly heated rock masses. We feel 

 therefore that the burden of proof should now be imposed on anyone 

 who asserts the contrary, for, even if some unconsidered factors 

 intervene to upset the calculations of the foregoing pages, he would 

 still be confronted with the difficulty of imagining a reasonable 

 configuration of the rock in depth, such as would insure that the 

 total pressure within the pore is not overbalanced by the pressure 

 to which the plastic rock surrounding it exerts. 



