34 J. M. Ordway on Waterglass. 
with a well purified silicate, it is possible to get at least as far as 
KSi, or NaSi,, and have as solution perfectly transparent. 
Crude waterglass, unless it is made in unalterable vessels and 
from absolutely pure materials, is sure to contain more or less 
saline and earthy impurities. But it appears from the foregoing 
experiments that these contaminations may be got rid of by 
several properly conducted precipitations,—the salts remaining 
in the alcoholic liquors while the earthy and metallic oxyds are 
toa single precipitation when a nice snore og is wanted for use 
in the arts. In such a case it will do to operate on a tolerably 
strong solution, say one containing twenty per cent of solid 
matter. But it ‘sho uld be observed ‘that weaker liquors allow of 
ineomp lete separation of the last ie of mother er but 
they soon clear by standing in a warm place. Soli 
Lei are commonly opaque and acquire their proper trans- 
parency only on being thoroughly drained. 
F 
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RMS 
7m 
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