188 Scientijic Intelligence.-—Miscellaneous. 
«2. Another proposed use of the water-glass is that of harden- 
ing cements, mortar, &c., so as to render them impermeable by 
water. ; 
“ Fourteen years since Anthon* of Prague proposed several ap- 
plications of the water-glass. Among others he suggests the ren- 
dering mortars water-proof. He also suggests that this substance 
might be beneficially employed as a substitute for size in white- 
washing and staining walls. It was demonstrated by several expe- 
riments, that carbonate of lime, mixed up with a weak solution of 
water-glass, and applied as a whitewash to surfaces, was not washed 
off by sponging with water, and that common whitewash, laid on in 
the usual manner with size, was rendered equally adhesive when 
washed over with water-glass. 
“© 2. The Stereochrome of Fuchs.—The formation of an inso- 
luble cement by means of the water-glass, whenever the carbonic 
acid of the atmosphere acts on this substance, or whenever it is 
brought in contact with a lime-salt, has been applied by Fuchs to 
a most important purpose. The stereochrome is essentially the 
process of fresco secco,} invested with the capability of receiving 
and perpetuating works of the highest artistic character, and 
which may be executed on a vast scale. Fuchs’s method is as fol- 
lows :{— 
“ ¢ Clean and washed quartz-sand is mixed with the smallest 
quantity of lime which will enable the plasterer to place it on the 
wall. The surface is then taken off with an iron scraper, in order 
to remove the layer formed in contact with the atmosphere; the 
wall being still moist during this operation. The wall is then al- 
lowed to dry; after drying it is just in the state in which it could 
be rubbed off by the finger. The wall has now to be jiwed, 2. ¢., 
moistened with water-glass.§ [An important point is not to use too 
much water-glass in moistening the wall.] This operation is usually 
performed with a brush. The wall must be left in such a condition 
as to be capable of receiving colours when afterwards painted on. 
If, as frequently happens, the wall has been too strongly fixed, the 
surface has to be removed with pumice and to be fixed again. Being 
* Neuere Mittheilungen tiber die Nutzanwendung des Wasser-Glases, 1840. 
This subject has been also fully treated by Kuhlmann in his “‘ Mémoire sur |’In- 
tervention de la potasse ou de la soude dans la formation des chaux hydrauliques,” 
&c., 1841.—Eapériences Chimiques et Agronomiques. 
t Vide Kastlake’s Materials for a History of Oil Painting, p. 142. 
{ These particulars were obtained by Dr Hoffmann from Mr Echter. A ste- 
reochronic picture by Echter, and a sample of the water-glass as prepared in 
Munich, were also exhibited by Dr Hoffman. 
§ The composition of the specimen was— 
Per cent. 
BME gio ko's'ts eS iageg pet iiCendeonec atten er ee 23°21 
MET ce Tas vecetcevsn ss ¥00 detactteer: ateeeaniata tty 8:90 
ONO 45 PIED. ROULERWTEL eon 2:52 
[The specific gravity of the solution 3°81.] 
