IMPROVEMENTS IN CONNECTION WITH - STONES FOR LITHOGRAPHIC PURPOSES "AL
Year: 1882

page_text: LETTERS PATENT to Peter Stuart of Edinburgh in the County of Mid Lothian,
North Britain for an Invention of "IMPROVEMENTS IN CONNECTION WITH
-
STONES FOR LITHOGRAPHIC PURPOSES
"
PROVISIONAL SPECIFICATION left by the said Peter Stuart at the Office
of the Commissioners of Patents on the 15th November 1882.
PETER STUART of Edinburgh in the County of Mid-Lothian, North Britain
IMPROVEMENTS IN CONNECTION WITH STONES FOR LITHOGRAPHIC PURPOSES."
This Invention relates to improvements in connection with stones for lithographic
purposes and whereby a much greater printing surface can be obtained from the
same weight of stone than hitherto and also whereby stones, when worn thin, can
be renovated so as to render them again useful for printing from without danger of
their breaking in the press.
-
Under this Invention lithographic stones of the usual or other thickness are
sawn or cut into slabs, of say an inch thick. These slabs are backed with artificial
stone composed of ground granite sand or like material and cement which when set
bas the property of withstanding a high breaking strain.
To enable the slabs of lithographic stone to be secured to the artificial stone
backing the edges of the lithographic stone are bevilled or they may have grooves
cut around them with or without holes also drilled in the back to make the
artificial stone adhere, or holes may be countersunk into the edge of the slab, and
the ends of metal rods or wires, bent underneath the stone, inserted into them.
The slab of lithographic stone is placed in a mould and the admixed ingredients
constituting the artificial stone in a plastic state poured in at the back of it and
so that the layer or backing of artificial stone shall adhere both to the back and
edges of the slab of lithographic stone or to the back of it merely.
To give still greater strength, wires or metal rods crossing each other or not may
be inserted in the artificial stone backing.
By this means a greater printing surface from the same weight of lithographic
stone is produced and the price of a stock of such stones is consequently
diminished.
L
When ordinary lithographic stones have been worn thin by treating them in
the usual manner they may be backed as herein before described,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Peter Stuart in the Great Seal Patent Office on the 12th May
1883.
PETER STUART of Edinburgh in the County of Mid-Lothian, North Britain.
IMPROVEMENTS IN CONNECTION WITH STONES FOR LITHOGRAPHIC PURPOSES,
My said Invention relates to improvements in connection with stones for
lithographic purposes and whereby a much greater printing surface can be obtained
from the 'same weight of stone than hitherto and also, whereby stones, when worn
thin, can be renovated so as to render them again useful for printing from without
danger of their breaking in the press.
And In Order that my Said Invention may be properly understood I now proceed
more particularly to set forth the system mode or manner in or under which the
same is or may be used or carried out in practice, reference being had to the
appended sheet of drawings and to the Letters and figures marked thereon.
Under my Invention lithographic stones of the usual or other thickness are sawn
or. cut into slabs, of say an inch thick. These slabs a, are, as shewn at figure,,1,
backed with artificial stone composed of ground granite, sand or like material and
portland roman or other cement which artificial stone when set, has the property of
withstanding a high breaking strain.
5.-75% **
To: Secure the slabs a, of lithographic stone to the artificial stone backing b, the
edges of the lithographic stone may be bevilled as seen at figure 1 or they may be
straight and have grooves cut around them as seen at c, figures 2 and 5, and
grooves or holes may also be cut in the back of the slab as seen at d, figures 2
and 4 to make the artificial stone adhere more firmly, or holes may be countersunk
into the edge of the slab and the ends of metal rods or wires, bent underneath the
stone, as seen at f figure 3, inserted into them or 1 or angle irons may be inserted
in the artificial stone backing, as seen at h figure 5, or wires or metal rods crossing
each other or not may be so inserted.
.
All the edges or sides of the lithographic stone slab a, may be surrounded with
the artificial stone backing b, or two sides of the slab only may be so surrounded
the backing at the other sides being cut straight down or flush with the edge of
the slab as seen at k, figure 4 or the backing may be so cut straight or flush with
the lithographic stone slab around all its sides.
When backing up the slab of lithographic stone it is placed in a mould and the
admixed ingredients constituting the artificial stone in a plastic state are poured in
at the back of it and so that the layer or backing of artificial stone shall adhere
both to the back and edges of the slab of lithographic stone or to the back of it
merely.
By this means a greater printing surface from the same weight of lithographic
stone is produced and the price of a stock of such stones is consequently
diminished.
When ordinary lithographic stones have been worn thin by treating them in
the usual manner they may be backed as hereinbefore set forth.
Having now described and particularly ascertained the nature of my said
Invention and several systems or modes in or under which the same is or may be
used or carried out in practice I would observe in conclusion that I am aware that
it has been customary to back lithographic stones with plaster of paris or common
cement and with slabs of slate or other stone. It is therefore to be understood
that I do not claim to have invented a system of backing lithographic stones
otherwise than as herein before set forth, that is to say what I consider to be novel

page_text: and original and therefore claim as the Invention secured to me by the hereinbefore
in part recited Letters Patent is.
Backing slabs of lithographic stone with artificial stone having when set a
higher breaking strain than the compositions or plasters hitherto used for that
purpose such artificial stone being composed of ground granite sand or like material
and Cement with or without the insertion of metal rods wires 1 or angle irons in
the composition substantially as described.
In Witness Whereof I the said Peter Stuart have hereunto set my hand and
seal this tenth day of May in the year of our Lord One thousand eight
hundred and eighty three.
Witness
GEO. M, CRUIKSHANK
Patent Agent
135 Buchanan St
Glasgow
PETER STUART (L.S.)