£04 Art of Printing from Stone « 
The processes employed are simple., but as only a 
brief account of them has yet been given, it may be of 
use at least to make known those followed in Ger- 
many. 
In the chemical printing office at Vienna three differ- 
ent methods are employed ; but that termed in relief is 
most frequently used. This is the general mode of 
printing music. 
The second method is the sunk. This is preferred 
for prints. 
The third method is the flat, or neither raised nor 
gunk. This is useful for imitating drawings, parti- 
cularly where the impression is intended to resemble 
crayons. 
For printing or engraving in this method a block of 
marble is employed, or any other calcareous stone, that 
is easily corroded, and will take a good polish. It 
should be two inches or two inches and a half thick, 
and of a size proportioned to the purpose for which it 
is intended. A close texture is considered as advan- 
geous. 
When the stone is well polished and dry, the hrst step 
is to trace the drawing, notes, or letters, to be printed, 
with a pencil. The design is not very conspicuous, but 
it is rendered so by passing over the strokes of the pen- 
cil a particular ink, of which a great secret is made. 
This ink is made of a solution of lac in potash, which is 
coloured with the soot from burning wax. This appears 
to be the most suitable black for the purpose. When 
the design has been gone over with this ink, it is left to 
dry, which commonly takes about two hours; but this 
depends much on the temperature and dryness of the 
air. 
After the ink is dry, nitric acid, more or less diluted 
according to the degree of relief desired, is poured on the 
