J. M. Ordway on Waterglass. 173 
Arr. XVUI.— Waterglass; by Joun M. Onpway. Part V. 
[Continued from vol. xxxv, p. 196.] 
dts Reaction with Slannates. 
Ing notice. The conditions, character, and results of the 
Stannate of Soda.—Time alters the crystallized salt, and dis- 
solved stannate of soda having just one equivalent of alkali to 
one of acid, soon begins to change and deposit an insoluble 
metastannate, leaving an excess of soda in the liquid. ence, 
_ whenever the really normal combination is wanted, it is best to 
make use of the freshly prepared crystals. 
ee he commercial “ preparing salt,” when it 1s free from arsenic, 
may be advantageously used to produce the pure stannate. 
ibe. . 
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