AMERICAN 
JOURNAL OF SCIENCE AND ARTS. 
[SECOND SERIES.] 
Art. XVI.— Waterglass ; by J. M. ORDWAY. 
Part I.—Hisrory anp MANUFACTURE. 
THE soluble alkaline silicates have of late years come into ex- 
tensive use in the arts, and seem likely to constitute a large and 
permanent branch of chemical manufactures. The common 
works on technology do not treat of them as fully as their pres- 
€nt Importance demands, nor can all that could be desir 
found within the limits of any single paper hitherto published 
on the subject.* It is here proposed therefore to collect details 
from various scattered memoirs, as well as from private experi- 
ence, and present a concise but more complete account of the 
history, manufacture, nature, and uses of the soluble silicates of 
potash and soda. 
The later alchemists were acquainted with the deliquescent 
tersilicate of potash,—K,8i,—the basis of liquor silicum. us 
Glauber, in giving his second method of testing sand for gold, 
says:—“Take one part of white quartz or sand, mix it with 
three or four parts of salt of tartar, or any other alkali, and put 
the mixture into a crucible, but so as not to fill more than one- 
third of it; since otherwise, in melting, the mixture would rise 
and flow out of the crucible. Let it stand [in the fire] half an 
hour that it may be well ignited and changed to a pellucid glass. 
* A pretty full resumé of all that had been published on Waterglass up to 1857, 
is given by Kopp in the Moniteur Scientifique, tome i, livraison 4™¢- 
Am. Jour. Sc1.—Szconp Series, VoL. XXXII, No. 95.—SEpPr., 1861. 
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