﻿532 Intelligence and Miscellaneous Articles. 



restricted areas of the same rock, due to superincumbent pressure, 

 faulting, and the intrusion of dykes, illustrating the various points 

 with data collected in the field. He also discusses and describes 

 experiments on the rate of desiccation and soakage of various rocks. 



He then describes a lengthy series of laboratory-experiments, which 

 he conducted with specially-devised apparatus of his own design to 

 afford a constant pressure and to eliminate all possible errors due to 

 lateral flow ; and in which he demonstrates that there is not a uniform 

 relation between flow and pressure in various rocks over a consider- 

 able range of pressure, and discusses the various phenomena which 

 were manifested. 



In the third portion of the paper he describes the various attempts 

 at determining the range of the cone of depletion in various strata, 

 and then proceeds to outline a method based upon an experimental 

 determination of the variation of internal pressure in a rock- mass 

 when charged with water and subjected to a considerable difference 

 of pressure on the two faces ; and in further elaboration of the theory, 

 he outlines a method of estimating the percentage-interference of 

 two contiguous wells in the same strata. 



In the concluding portion of the paper he discusses data collected 

 during various hydrological surveys, and points out the influence of 

 surface-configuration and stratigraphical sequence on the sub-surface 

 water-contours. 



LX. Intelligence and Miscellaneous Articles. 



ATOMIC CONDUCTIVITIES OF THE IONS. 

 BY PHILIP BLACKMAN. 



A corkection : — Phil. Mag. 1906, xii. p. 151, lines 7 and 8, 

 instead of 



"By adding ^=340," 



read : — 



" By performing all the possible subtractions and adding together 

 the equations thus produced, then, on solving the resulting equation 

 4-749/i n = 1618, it is found that /; H = 340." 



The tables for K, K 7 , K 2 , &c, and Rv HX , Bv 1IX , Ev HX , &c, 

 used in the construction of the table of " atomic conductivities," 

 will be found in full in the ' Chemical News,' 1906, vol. xciv. 

 p. 164, " Molecular Conductivities : Quantitative Relation." 



