IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL STONE
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Benjamin Joseph Barnard Mills
at the Office of the Commissioners of Patents, with his Petition,
on the 22nd February 1869.-A communication from abroad by
William Munroe, of Boston, in the State of Massachusetts, in the
United States of America.
I, BENJAMIN JOSEPH BARNARD MILLS, of 35, Southampton Buildings,
in the County of Middlesex, Patent Agent, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL
STONE," communicated to me from abroad by William Munroe, of Boston,
in the State of Massachusetts, in the United States of America, to be as
follows:-
The Invention relates to a new and improved method for the formation
of artificial stone, using for the purpose fragments, chips, or powder of
natural stone, or sand or other mineral substance.
In the preparation and manufacture of such artificial stone is used as
a cementitious agent or agents calcined magnesia and bittern water (the
residuum of salt works, generally that of sea water from which the salt
has been extracted by the process of evaporation), or its equivalents,
artificially prepared.

page_text: And the Invention consists in the production of an artificial stone by
combining fragments, chips, or powder of stone, or other mineral
substance with calcined magnesia and bittern water. The proportion of
broken or powdered stone or other mineral substance and of magnesia
which is preferred is about twenty parts by weight of stone or other
mineral substance and one part by weight of magnesia. Those two
substances in about those proportions are first to be thoroughly mixed
together and then wetted with a sufficient quantity of bittern water to
make a stiff mortar. When the bittern water is thoroughly mixed with
the other materials so as to moisten the whole mass the mortar so pre-
pared is ready to be put into any desired form. This is done either by
simply moulding the mortar into form with any convenient tool, or by
putting it into moulds, when it should receive a convenient amount of
pressure. It should then be taken from the moulds and placed in the
air for drying and hardening. This it will do in a short time without
the application of artificial heat, but artificial heat may be applied to
hasten the hardening process if desired. For some purposes it is found
useful to apply water to the stone while hardening, but neither the
application of artificial heat nor water are generally necessary. The
stone so made answers well for all the purposes for which the natural
stone is used, and for some purposes it may be made of various colours.
This process is valuable for making many articles used by artizans or
others for sharpening, dressing, or polishing steel and other metals, such
as grindstones, whetstones, or oilstones, emery stones, and wheels.
To secure the best result it is important that the magnesia and bittern
water should thoroughly permeate the spaces between the broken or
powdered stone, so as to leave no interstices unprovided with those
cementitious materials, and the product will generally be much improved
by the application of considerable pressure.