186 J. M. Ordway on Waterglass. 
1.—50 grams of a liquid containing 20 p. c. of Na,Si,, mixed with 
100 grams of a 20 p. c. chlorid of sodium solution, gave a copious pre- 
cipitate which contracted greatly by standing 24 hours. The clear super- 
natant liquor being then decanted, the deposit was washed several times 
with cold water. Under this treatment, the product changed from a 
dense curd to a light flocculent matter, which, after drying in the air, 
weighed only 0282 grms. It contained 0-224 grms. of silica. 
2,—100 grams of the same chlorid of sodium solution having been 
acid, afforded 31°58 p. c. of SiO, and 20-95 parts of chlorid of sodium. 
Deducting from the latter the 5-05 p. c. of preéxisting NaCl, we have 
15-9 parts of chlorid due to the soda and showing 8°23 p. c. of NaO. 
By the same mode of examination, the mother-liquor was 
found to contain 14:09 p.c. of NaCl, 1-41 p.c. of SiO,, and 
0°55 p.c. of NaO; the latter two constituents being in such pro 
portion as to make up NaSi,.,*. 
3.—Again, 100 grams of the 20 p. ¢. chlorid of sodium solution, weré 
mixed with 50 grams of 20 p. c. Na,§j,. After a time the precipitate 
was collected in a cloth and subjected to the action of a powerful press- 
The solid, nearly transparent mass weighed 12-1 grams, and was wholly 
soluble in cold water. 
jected to the action of pure water is forcibly shown by compat: 
ison of the less than 0°3 grms. of light matter in No. 1 w ° 
17-2 grms, of dense curd in No. 2, or with the 12-1 grms. ° 
rd i : 
Secondly, let us suppose the 55 p. ¢. of water in the sincere 
4 
* In reducing the composition to a uniform representation by empirical equiv® 
lents, it may be an ithe vasueut on the course adopted in Part III, to take ai. of 
base instead of one hundred, and let the acid come in decimals. Thus « NaSiy-s 
is more compact than “Nay oSiz¢o.” 
