696 Transactions of the American Institute. 



manuscript is written, by placing it under a leaf of the book and 

 rubbing the hand over the paper, an excellent copy is obtained. It 

 is a valuable aid to business men heretofore accustomed to the irksome 

 process, which requires a wet brush, absorbing paper, a press, and 

 some patience. 



MuKAL Painting. 



The application of colors in the decoration of walls and ceilings has 

 been greatly facilitated by the use of alkaline silicates, or water-glass. 

 Formerly, fresco painting was executed on stucco made of lime or 

 gypsum, into which the color or pigment will sink and become durable, 

 but it is essential that in this case the whole painting be completed 

 before the coating of stucco is dry, for after it has assumed that con- 

 dition the painting cannot be retouclied. Very few, if any, of the 

 ancient paintings found on church walls are genuine frescos, as has 

 been generally supposed ; they are simply distemper paintings, that 

 is to say, colors ground up with size and water, applied to common 

 plaster, Fuchs was the first to obviate the difiiculties found in true 

 fresco work. His improved method consists in applying to the surface 

 water-glass cement, made by mixing a soluble silicate of soda with 

 powdered marble, with dolomite, or with quartz sand, and a little dry 

 slaked lime. Upon this coating the painting is made by means of 

 mineral colors ground up with pure water. The work may be pro- 

 longed for any required time. When it is finished the colors are fixed 

 by washing the surface with a mixture consisting of four or five parts, 

 by measure, of water-glass saturated with silica, and one part of 

 monosilicate of sodium, the whole being diluted with one-half its 

 bulk of water. Tiiis kind of silicious painting is very durable, and 

 may be applied to earthenware or tiles after their surfaces have been 

 prepared with water-glass. The process invented by Kuhlmann is 

 more simple, as less care is required in preparing the surface and fixing 

 the painting. He grinds his colors with an alkaline silicate, which 

 may ev6n be applied to wood, provided it is free from resin. When 

 a very porous stone is to be covered, it is best to silicify it before 

 applying the colors. A silicious solution, of fifteen to twenty degrees 

 Baume in strength, may be mixed with colors ground in water ; but 

 for painting on glass or earthenware the solution should be more 

 concentrated. 



For the benefit of those who wish to apply, under their own super- 

 vision, water-glass for paintings and decorations, we subjoin the 

 following information from The London Builder : 



