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C. Bancs — Compress > Unlit y of Colloids. 



property of re-cementing into complete coherence, a gradually 

 more marked relief of pressure will occur above the meniscus : 

 for this pressure is slowly dissipating itself* throughout the 

 whole upper column, access to which is shut off below. Hence 

 in the lapse of time the original conditions will occur; there 

 will be fresh rupture at the meniscus and a new projectile 

 until the whole column has in this intermittent manner been 

 subjected to constant hydrostatic pressure at the meniscus. 



Briefly, pressure is transmitted upward as an advancing 

 wave whose amplitude diminishes with the distance above the 

 meniscus. This is followed by gradual subsidence of pressure 

 throughout the column, and anon by a new pressure wave of 

 like rapid motion upward and diminishing amplitude, but of 

 less intensity ; and so on. 



Fig. 5. Distribution of pressure, p, axially along the height, h, above the 

 meniscus. 



The annexed diagram, fig. 5, will make my meaning clearer. 

 Let the height of the axial point be laid off vertically and 

 pressure horizontally. Let g be the pressure-gradient for 

 which rupture ensues at the meniscus (ordinate zero), pressure 

 being here constant. Then the curve 1 may represent the dis- 

 tribution of pressure in the solid colloid at the instant of rup- 

 ture ; 2, the distribution immediately after rupture ; 3, the dis- 

 tribution at a much longer time after rupture, when the upper 

 part of the tube has partially accommodated itself to the new 

 conditions, pressure increasing at the top of the colloidal 

 column and decreasing gradually near the meniscus. Finally, 

 in tiie lapse of time, 4 represents a pressure distribution having 

 the same initial gradient g and conditioning fresh rupture. 



*The volume decrement of a relatively small volume becomee the reduced 

 volume decrement of a relatively large volume. 



