J. M. Ordway on Watergiass. 155 
to make trial of the waterglass. Therefore with Dr. Pettenkofer 
as an associate, he made many experiments which showed its 
entire efficiency as a protective agent, and it soon assumed a 
greater importance than he had at first attached to it. They then 
labored to find some cheap and easy mode of preparation, which 
might render waterglass available for economical uses. In the 
first place they made liquor silicum, and dissolved in one portion 
the well washed silica precipitated from another portion. This 
method was too costly, and the product was not all that could 
desired, since it contained too much carbonate of potash. 
Finally by trying the direct fusion of various mixtures of pot- 
ash, sand, and charcoal, they got a product which, when pow- 
dered, dissolved slowly but almost completely in boiling water, 
ording a solution free from carbonic acid and perfectly satu- 
rated with silica. 
In making the article for actual use they took for each charge 
80 lbs. of well purified potash, 45 lbs. of quartz sand, and 8 lbs. 
of powdered wood charcoal. This was melted in a refractory 
crucible, and at the end of five or six hours, when the well fused 
mass had subsided into a quiet state, they dipped it out with an 
Iron ladle and threw in a fresh charge. 
_Huchs found in one sample of the dissolved silicate propor- 
tions corresponding to K,Si;. In another analysis he obtained 
somewhat more silica and less alkali. 
They also made a silicate of soda with such relative quantities 
of materials as should give NaoSi, ; but in Fuch’s last work, pub- 
lished since the author's death, he recommends 45 Ibs. of quartz, 
23 lbs. of dry carbonate of soda, and 8 lbs. of charcoal, which 
Would make NasSis. Perhaps the recommendation was given on 
theoretical grounds, for ms a product is altogether too hard of 
solution for practical use. In fact Fuchs, for most of his exper- 
iments, took potash waterglass, and the potash silicates are more 
soluble than the corresponding soda compounds, 
Since 1825, owing to the enormous extension of the soda 
commerce it varies from NaSig to NasSiy. : 
; nder consideration the Angli- 
1 a . ion ‘soluble glass. : 
ess Brin oe tat te ning be got rid of by calling 
