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University of California Publications in Geology [Vol. 13 



general increased by pressure and heat, and valency is reduced; 

 diffusion and gas expansion are also increased ; and as depth increases 

 there is probably an increasing tendency for one substance to mingle 

 with another, water permeating everything, and every substance dis- 

 solving in water to extents unknown within the horizon of observation. 

 There is an increasing tendency for dissolved substances to ionize, and 

 for ions to still further dissociate, every substance thus tending toward 

 reduction to the atomic state, maximum dispersion and commingling. 

 On the other hand as the surface is neared there must be the reverse 

 of these tendencies, valency increasing, ions becoming more complex, 

 solubility and diffusion diminishing. In the depths the tendency must 

 be for reactions to occur in such a manner as will result in the greatest 

 economy of space and absorption of heat ; therefore, where crystalliza- 

 tion is occurring the molecules will be the most complex ones possible, 

 the paucity and largeness of individuals being most economical of 

 space ; but as the surface is approached there must be the reverse 

 tendency, namely, for simpler molecules to form, or for the more com- 

 plex ones to become unstable and to break down. Examples of this 

 are seen in the complexity of the feldspars and pyroxenes, which 

 are xmstable at the surface and weather easily, saussuritization and 

 iiralitization often taking place some distance below the surface. 



The intimation above, that water may permeate everything in the 

 depths, requires explanation. I venture this as a probability partly 

 on the basis of theory, and partly on the evidence of the microscope, 

 where surface alterations affect such minerals as feldspar, for instance, 

 at some distance back from cleavages, a diminishing cloudiness being 

 visible in the unfractured and uncleaved mineral within its inter- 

 molecular space at a distance from any visible opening. Ions evi- 

 dently enter and leave those intermolecular regions ; and water mole- 

 cules being among the smallest, probably smaller than the ions in 

 question, they could as easily diffuse into that region as the other 

 substances coidd diffuse out. If the intermolecular space of rock 

 minerals is accessible to water it must be assumed present. Perhaps 

 the migration of the mineral ions might even be taken as an evidence 

 of the presence of water, since it constitutes a good medium for dif- 

 fusion ; and the ions of mineral matter could not be supposed to have 

 moved away by any other process. The fact that such hypothetical 

 water does not show itself by reactions with the minerals is no evi- 

 dence against its presence ; since whether the minerals are of igneous 

 or aqueous origin they were probably formed or aggregated in its 

 presence and are stable there under the conditions of the depths. 



