J. M. Ordway on Waterglass. 341 
while it is sometimes in the liquid state, under other circum- 
i i ass. And on 
the other hand, a pretty alkaline potash silicate may be precipi- 
tated in the fluid form. L 
Y per cent of water, and are somewhat less alkaline, and 
considerably freer from foreign salts than the silicates from which 
they have been derived. And in most cases, they dissolve read- 
ily in cold water. ; 
ery few combinations of silica and alkalies have been found 
Capable of crystallization. Fritzsche* obtained the sesquibasic 
silicate of soda in the form of rectangular prisms of the compo- 
Sition Nag Sig H27; also the same salt under another form with 18 
€qs. of water. And Yorke} mentions erystals containing 21 
zable. The details of his researches, however, have not been 
rod 
And 
its ad a quality which it possesses in a degree not 
Ves on 
i : i is last trifling change, 
tenacious jelly. With the exception of this last trifling ¢ : 
Solutions te reaicolious of whatever strength — awed - sj 
ept from the air and from frost, remain unaltere : - ye son 
When they are exposed to intense cold, a part o 
freezes, but reunites on thawing. 
of water. This must : 
for'a stratum of bisileate of potash, about a quarter of an inch 
ling, Traité de Chimie,—d. Francaise, 2¢, ii, p. 288. 
t Kopp and Will’s Jahresbericht for 1857, p. 162. § Id. p. 1147. 
+ Comptes Rendus, xliii, p. 1148. 
