OBSERVATIONS ON THE DAUBREE EXPERIMENT ii 



described ; that his temperature and temperature difference played 

 no part further than the subsidiary one of decreasing the surface 

 tension of the water and hence the observed pressure difference. 

 Thus it was possible to include in Table 1 the calculated pore 

 diameter of Daubree's sandstone as deduced from his values of 

 temperature and pressure difference. 



GEOLOGICAL BEARINGS 



As long ago as 1881, Osmond Fisher pointed out^ that the 

 Daubree experiment was effective merely because there was a 

 surface of separation; and as Kemp,^ in citing his opinion, writes: 



The experiment gives no ground for thinking that water would move 

 through the heated walls confining a reservoir of molten rock and become 

 involved in the latter. 



To quote from Osmond Fisher: 



Capillary action can be made to do great things But it cannot 



cause a liquid to flow continuously through a tube, however short; for, if it 



could, it would give us perpetual motion If there were a cavity filled 



with vapor, it is possible that the density of the vapor, and therefore its pres- 

 sure, might be increased to a certain extent, by the evaporation of the water 

 from the extremity of the capillary tubes, and that was what occurred in 



the experiment of M. Daubree Still further, the existence of capillary 



communication of water from the surface may be doubted. For if there were 

 supposed a capillary tube extending from the bottom of the ocean, the pressure 

 at the lower end of this tube would be that of the water contained in it plus 

 that, if any, arising from capillarity, while the pressure of the crust around its 

 mouth would be that due to the weight of the crust. This latter would be the 

 greater of the two: consequently the liquid upon which the crust rested, 

 having a tension [being subject to a pressure] equal to the weight of the 

 crust, would force back the water in the tube, and if it were not too viscous 

 would itself occupy the tube.^ 



Now it is hard to imagine a permanent configuration, except 

 for comparatively small depths, such that this closing-up of the 



' Osmond Fisher, Physics of the Earth's Crust, London, 1889, 2d ed., p. 143. 



^ J. F. Kemp, "Role of Igneous Rocks in the Formation of Veins," Trans. Am. 

 Min. Eng., XXXI (1901), 177. 



^Op. cit., pp. 144-45. We may note that the argument does not postulate that 

 the material under the "crust" be liquid in the restricted sense of the word; it is 

 vaUd if the rocks at that depth can flow, a condition which surely obtains except at 

 comparatively shallow depths. 



