270 



MOREY 



ART. G 



mined pressure-temperature curves; and Fig. 8, a diagrammatic 

 representation of the same curves. When equation (16) is 

 applied to the ternary equilibrium K2O • SiOj • 5H2O + 



KzOSiOz 



^20Si<^y2^2 



/fsOSiO^H^ 



H20 2SfOg 



K20-4Si'02 



HzO 



SiOp 



Fig. 5. The ternary system, H2O-K2O • SiOz-SiOa. The full lines are the 

 isothermal polybaric saturation curves at the temperatures indicated. 

 The broken curves are the boundary curves between the various fields. 



K2O -28102 + L + V (curve 6c, Figs. 5-8), the curve which pro- 

 ceeds from the quintuple point Q2to quintuple point Qx, it becomes 



di 



(t;' - V) -\- \ — W - v^) - - — {v" - v^) 



i-121 



U2I 



in which S' and S" represent the compounds K2O • Si02 • ^H20 

 and K20-2Si02- At Q2, the terms (n^ - 17") and (v^ - V), both 

 of which are negative and much larger than the other terms, 

 preponderate; dp/dt is positive. As with increasing tem- 



