J. M. Ordway on Waterglass. 177 
of potash sulphate. The waterglass was such as had been well 
purified by precipitation with alcohol. 
While treating this part of our subject we will take the form- 
ula adopted in planning the experiments, and consider silicic 
6. 80g. of a solution containing 14 p. c. of NaO SnO., were mixed 
with 32 9. of a 29 p.c. solution of NaO.2SiO,, so as to have in the 
united liquors Nag Sn Big, : 
There was no apparent change at first, but, in the course of two days, 
it became an opaque, consistent jelly from which no liquor could be de- 
canted. 
