346 J. M. Ordway on Watergilass. 
ficial glaze of carbonate is removed, by scouring with sandstone 
or by washing with weak phosphoric acid. The plaster is then 
repeatedly soaked with a dilute solution of very silicious water- 
glass, the silicate being allowed to dry and fix between the con- 
secutive drenchings. ‘The well saturated ground is now covered 
with a thin stratum of nicely prepared, but meagre, mortar, and 
this coat is treated in the same way as the basis. When the 
silicatization is finished, the surface should still be rough and 
absorbent. If it is glazed over so as to be too impervious, Fuchs 
recommends to open the pores by pouring on alcohol and burn- 
ing it off. On the wall so prepared, the painting is executed 
with colors ground up with mere water. And finally the pig- 
ments are fixed by repeated affusions of a rather alkaline double 
silicate of potash and soda. To avoid any displacement of the 
colors, the fixing liquid is thrown on the first time, in the form 
of a fine spray, by means of a suitable syringe. As the artist 
must frequently change his palette, it is impractieable to use the 
aints mixed directly with waterglass, since the silicate woul 
always drying up, and the brushes would get stiff and hard. 
Brushes soaked with a silicate should never be allowed to dry 
it is only necessary to allow one coat to dry before laying 0? 
another, but this would be hardly consistent with a solid fixa- 
tion. nal varnishing with oil is recommended, to 1m 
lustre and prevent saline efflorescence. 
White oil paint is modified in tone by the color of the oil, oni 
is farther hable to get dingy by a chemical change — on 
When a silicious paint is to be laid on a metallic surface, it 
* Wagner's Jahresbericht, iii, 133, the fact 
for 
ving been e t 
two years or so, is so far changed that the white lead rubs off with the. sey 
This however is rather an extreme case, and it is said by practical ae od 
: aired e 
manufact jisad- 
‘White oxychlorid of lead and zine white are not considered liable to this 
