NEW METHOD OF AND APPARATUS FOR CLEANING LITHOGRAPHIC STONES
Year: 1876

page_text: LETTERS PATENT to William Lloyd Wise, of Chandos Chambers, Adelphi, in
the County of Middlesex, for the Invention of a "NEW METHOD OF AND
APPARATUS FOR CLEANING LITHOGRAPHIC STONES." A communication from
abroad by Dr. F. Wilhelmi, Manufacturing Chemist, of Reudnitz-Leipzig,
Kingdom of Saxony, German Empire.
PROVISIONAL. SPECIFICATION left by the said William Lloyd Wise at the
Office of the Commissioners of Patents on the 22nd July 1876.
WILLIAM LLOYD WISE, of Chandos Chambers, Adelphi, in the County of
Middlesex. "NEW METHOD OF AND APPARATUS FOR CLEANING LITHOGRAPHIC
STONES."
This is an Invention communicated to me from abroad by Dr. F. Wilhelmi. It
relates to a new method of and apparatus for chemically cleaning lithographic
stones.
The method hitherto generally in use for cleaning or removing prints or drawings
from lithographic stones and preparing the stones for further use is the following:-
The printed or marked surfaces of two stones are ground together with water and
sand until the prints or drawings entirely disappear. For this purpose, in the first
instance, sand of a coarse description, then a finer sort, and finally very fine sand
have been used in order to obtain a well ground and smooth surface.
polish has been given to the plates by means of pumice stone.
The last
In order to accomplish this tedious process of grinding several devices have been
constructed by which the upper stone has been set in grinding motion by a lever
moved by hand. Lithographic establishments of greater extent are supplied with
devices in which the grinding operation is completed by steel plates moved by
steam power. However, the greater number of lithographers are unable to employ
steam, and are obliged to make use of the old process of hand grinding.
Now in order to essentially facilitate the cleaning process, and to diminish the
costs of the same, my foreign correspondent adopts the following method:-The
surfaces of the stones are first cleaned by water and then dried. By wiping tho
surfaces with benzine or turpentine oil the whole of the printing ink is taken off

page_text: from the surface. The stone is now treated by means of the apparatus herein-after
described with hydrochloric acid containing chloride of benzoid. When the
operation with the said apparatus and acid has taken place a simple smoothing of
the stone surface with pumice stone will suffice to prepare the stone for the
reception of new drawings or prints. The apparatus consists in its main part of a
hollow body of burned clay, earthenware, porcelain, or other suitable material,
whose diameter will vary according to the size of the stone to be treated. The
bottom of the hollow body is made with a perfectly plane surface, which is pierced
with a number of small holes. The upper part of the hollow body terminates in a
tube-like mouthpiece for the reception of a glass receptacle or reservoir.
receptacle or reservoir has in its upper part an aperture (provided with a stopper)
for fitting the receptacle or reservoir, and has a tube-like downward projection, with
a glass valve for regulating the passage of the hydrochloric acid containing chloride
of benzoid. The apparatus is made with two handles for purposes of manipulation.
The lateral parts of the lower portion of the body are provided with two rims, so
that a cloth made of wool or of asbestos covering the under plane surface of the
apparatus may be fastened thereto.
This
The complete apparatus is used for grinding the surface of lithographic stones,
during which action the acid employed drips from the reservoir through the hollow
body on. to the inner surface of its perforated bottom, whence the acid proceeds
through the small holes to the cloth, underneath which it penetrates. The result of
this operation on the stone by means of the apparatus and of the acid is rapid and
efficacious.
The construction of the apparatus may be varied without departure from the
distinctive characteristics of the Invention, and in lieu of the acid herein-before
mentioned other acids, as, for example, muriatic acid, sulphuric acid, nitric acid, et
caetera, may be employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Lloyd Wise in the Great Seal Patent Office on the 16th
January 1877.
WILLIAM LLOYD WISE, of Chandos Chambers, Adelphi, in the County of
Middlesex. cr
NEW METHOD OF AND APPARATUS FOR CLEANING LITHOGRAPHIC
STONES." A communication from abroad by Dr. F. Wilhelmi, Manufacturing
Chemist, of Reudnitz, Leipzig, Kingdom of Saxony, German Empire.
This is an Invention communicated to me from abroad by Dr. F. Wilhelini. It
relates to a new method of and apparatus for chemically cleaning lithographic
stones.
The method hitherto generally in use for cleaning or removing prints or drawings
from lithographic stones, and preparing the stones for further use is the following:-
The printed or marked surfaces of two stones are ground together with water and
sand until the prints or drawings entirely disappear. For this purpose, in the first
instance, sand of a coarse description, then a finer sort, and finally very fine sand,
have been used in order to obtain a well ground and smooth surface. The last
polish has been given to the plates by means of pumice stone.
In order to accomplish this tedious process of grinding several devices have been
constructed by which the upper stone has been set in grinding motion by a lever
moved by hand. Lithographic establishments of greater extent are supplied with
devices in which the grinding operation is completed by steel plates moved by
steam power. However, the greater number of lithographers are unable to employ
steam, and are obliged to make use of the old process of hand grinding.
Now in order to essentially facilitate the cleaning process, and to diminish the
costs of the same, my foreign correspondent adopts the following method:-The
surfaces of the stones are first cleaned by water and then dried. By wiping the

page_text: surfaces with benzine or turpentine, or by rubbing with snake stone, the whole of
the printing ink is taken off from the surface. The stone is now treated by means
of the apparatus herein-after described, with hydrochloric acid containing benzylic
chloride, the proportions being one hundred parts by weight of concentrated
hydrochloric acid mixed thoroughly with 0.5 parts by weight of benzylic chloride.
In practice this mixture may be colored with red or pink vegetable coloring matter.
I dilute the mixture with water to 8° Beaumé. The coloring is not essential; it
may be omitted if preferred for convenience. When the operation with the said
apparatus and acid has taken place a simple smoothing of the stone surface with
pumice stone or snake stone will suffice to prepare the stone for the reception of
new drawings or prints. The apparatus is shewn in the accompanying Drawings,
wherein Fig. 1 is a sectional elevation, and Fig. 2 a plan. Its main part consists of
a hollow body a of burned clay, earthenware, porcelain, or other suitable material
whose diameter will vary according to the size of the stone to be treated. The
bottom a of the hollow body is made with a perfectly plane under surface which
is pierced with a number of small holes b. These holes should have a diameter of
about one millimetre. The upper part a² of the hollow body terminates in a tube-
like mouthpiece c for the reception of a glass receptacle or reservoir & of the kind
well known in chemical laboratorics as a "separatory." This receptacle or reservoir
has in its upper part an aperture (provided with a stopper e) for filling the
receptacle or reservoir d, and has a tube-like downward projection f, with a glass
stop-cock g for regulating the passage of the hydrochloric acid containing benzylic
chloride. The apparatus is made with two handles h for purposes of manipulation.
The lateral parts of the lower portion of the body are channeled or provided with
two rims i,, so that a cloth 7 made of wool or of asbestos covering the under
plane surface of the apparatus may be fastened thereto by a cord or wire passing
around the cloth in the channel.
The complete apparatus is used for polishing the surfaces of lithographic stones
by rubbing the said surfaces with the cloth covered face of the apparatus, during
which action the acid employed drips from the reservoir a through the hollow body
a on to the inner surface of its perforated bottom, whence the acid proceeds through
the small holes b to the cloth, underneath which it penetrates, thus acting upon the
surface of the stone. The result of this operation on the stone by means of the
apparatus and of the acid is rapid and efficacious.
The construction of the apparatus may be obviously varied without departing
from the distinctive characteristics of the Invention, and in lieu of the acid
herein-bofore mentioned sulphuric acid or nitric acid may be employed with the
benzylic chloride in the proportions already stated, i.e., one hundred parts by weight
of acid to 05 parts of benzylic chloride.
Having described the nature of the said Inveution, and explained the manner of
performing it as communicated to me as aforesaid, I desire to have it understood that
what I consider to be novel and original and therefore claim as the Invention secured
to me by the herein-before in part recited Letters Patent is, the method substan-
tially as herein-before described with reference to the accompanying Sheet of
Drawings of cleaning lithographic stones by the use of chemical agents. I also
claim the combination of parts constituting the improved apparatus for that
purpose, constructed, arranged, and operating as shewn in and described with
reference to the said Drawings.
In witness whereof, I, the said William Lloyd Wise, have hereunto set my
hand and seal, this Sixteenth day of January, in the year of our Lord
Witness,
F. J. BROUGHAM.
W. LLOYD WISE. (L.S.)