i84 



N. L. BOWEN 



further cooling some solution is left that does not crystallize 

 at aU. 



It is plain from the outline of crystallization given that we have 

 a reaction pair, KaSiaOj and K2Si20.,-HzO and also a discontinuous 

 reaction series, K2Si03-K2Si03'^H20-K2Si03-H20. Each member 

 of the series is produced from the preceding member by reaction 

 with the liquid. The series is distinct from a continuous reaction 



K>SiO. 



H,0 SiO. 



Fig. 4. — Equilibrium diagram of the system, HjO-KzSiOj-SiOj 



series in that changes of composition are discontinuous, taking 

 place in steps and not by insensible gradations as in the continuous 

 series. 



The consequences of the existence of this reaction series have 

 been pointed out in the foregoing. Under certain conditions of 

 crystallization we may get simply the three phases KzSiOj, K2Si20s, 

 and KaSiOs -11120. Under other conditions we may get a part or 

 all of a long chain of products including the foregoing three and in 

 addition K2Si20s-H20 and K^SiOj-HjO. Moreover, when crystal- 

 lization runs far down in the series we may obtain a water-rich 



