FROM ORTHOCLASE FELDSPAR WHYTE 151 



but its presence confirms the fact of decomposition. After 

 arriving at this conclusion of progressive decomposition it is 

 interesting to recall Griinwald's experiments on the decomposi- 

 tion of feldspar by electrolysis. After fourteen repetitions he 

 obtained about one-third the total potash content, and claimed 

 to obtain complete decomposition by continuing the process. 



With regard to the action of sulphur dioxide the same con- 

 clusion may be drawn, with this difference — that the percentage 

 decomposition by this agent is much greater. 



When platinum sponge was added to the reaction mixture 

 no additional change was observed. 



In summary, then, it is concluded: First, SO2 is more 

 effective than CO2 in decomposing feldspar. 



Second, Heat and agitation have a small value in combination 

 with an active chemical agent. 



Third, Platinum as a catalyst is of no value in this reaction. 



Fourth, the value of the time factor beyond two or three 

 hours is nil. 



Fifth, The decomposition of feldspar is of the nature of an in- 

 complete chemical reaction, the point of equilibrium being 

 definite and appreciably different in the cases of SO2 and CO2. 



This is readily explained by the ionic hypothesis. Sulphurous 

 acid is a weak acid and carbonic acid is very weak; conse- 

 quently the degree of ionization is very small. The formation 

 of a very small amount of the largely ionized salts of these 

 acids is sufficient to repress the ionization of the acids, thus 

 bringing about a state of equilibrium at a very early stage. This 

 also explains why the time and pressure factors are of practically 

 no value while the products of the reaction remain in the reaction 

 mixture. 



Sixth, As a process for extracting potash from orthoclase 

 feldspar, this method is valueless. 



