A NEW COMPOUND FOR THE MANUFACTURE OF TERRA COTTA
Year: 1878

page_text: LETTERS PATENT to Charles Edward Appleby, of Kensington, in the County
of Middlesex, Civil and Mining Engineer, for the Invention of "A NEW
COMPOUND FOR THE MANUFACTURE OF TERRA COTTA."
PROVISIONAL SPECIFICATION left by the said Charles Edward Appleby at
the Office of the Commissioners of Patents on the 5th June 1878.
CHARLES EDWARD APPLEBY, of Kensington, in the County of Middlesex, Civil
and Mining Engineer. "A NEW COMPOUND FOR THE MANUFACTURE OF TERRA
COTTA."
My Invention relates to a new and novel compound which is designed to furnish
a material for the manufacture of terra cotta ware of all kinds, of a nature superior
to that which is now generally employed for such manufacture, including all articles
now made for architectural and ornamental purposes, stoneware facing, and
enamelled bricks and chimney tops.
This improved compound will be found superior to the compound generally
employed in manufacturing terra cotta from its being capable of being burnt to a
much higher temperature than that generally used, in consequence of which the
whole body is vitrified without producing the shrinkage generally resulting from
such higher temperature, or only to a considerably smaller extent, and from the
purity and indestructibility of colour which can be obtained and strength of
material.
From this compound will be obtained a correctness and cleanness of design not
usually arrived at, and complete resistance to the action of the weather and frost,
which has so injurious an effect on most terra cotta goods when exposed for a long
time, and in addition the colours obtained can be varied from pure white to deep
red, and through the various shades of brown, or any other shade desired,
The improved compound consists of an admixture of the decomposed granite or
elvan which is found in certain districts in Cornwall, and more especially in the

page_text: district of Calstock, and westward of the same, lying in a perpendicular or slightly
inclined "sett" or "vein," with a suitable plastic clay, such as that obtained at
Newton Abbott in Devonshire, or at Poole in Dorsetshire, according to the colour
and fineness of the goods to be manufactured, and of a certain proportion of calcined
material known as natural grog. The proportion in which the admixture of these
various materials is made varies with the quality and colour of the goods to be
manufactured, and ranges from 10 to 30, or even 40, per cent. of plastic clay, 50
to 80 per cent. of the decomposed granite or elvan, and 5 to 20 per cent. of natural
grog. The decomposed granite or elvan having been ground fine in admixture with
water, is combined or mixed with the plastic clay in suitable proportions and with
the "natural grog
in a suitable vessel, so as to form a paste or dough, which can
then be worked into the required form for terra cotta goods, stoneware, and bricks
of various kinds. It is then burnt in kilns in the ordinary way, but, by preference,
to a vitrifying heat, so as to give it a non-parous body, and impermeable to the
atmosphere.
"
SPECIFICATION in pursuance of the conditions of the Letters Patent, and of
an Order of the Lord Chancellor, filed by the said Charles Edward Appleby
in the Great Seal Patent Office on the 17th December 1878.
CHARLES EDWARD APPLEBY, of Kensington, in the County of Middlesex, Civil
and Mining Engineer. "A NEW COMPOUND FOR THE MANUFACTURE OF TERRA
COTTA."
My Invention relates to a new and novel compound which is designed to furnish
a material for the manufacture of terra cotta ware of all kinds, of a nature superior
to that which is now generally employed for such manufacture, including all articles
now made for architectural and ornamental purposes, stoneware facing, and enamelled
bricks.
. This improved compound will be found superior to the compounds generally
employed in manufacturing terra cotta from its being capable of being burnt to a
much higher temperature than that generally used, in consequence of which the
whole body is vitrified, without producing the shrinkage generally resulting from
such higher temperature, or only to a considerably smaller extent, and from the
purity and indestructibility of colour which can be obtained and strength of
material.
From this compound will be obtained a correctness and cleanliness of design not
usually arrived at, and complete resistance to the action of the weather and frost,
which has so injurious an effect on most terra cotta goods when exposed for a long
time, and in addition the colours obtained can be varied from pure white to deep
red, and through the various shades of brown and other colours.
The improved compound consists of an admixture of an admixture of the decomposed
granite or elvan which is found in certain districts in Cornwall, and more especially
in the district of Calstock, and westward of the same, lying in a perpendicular or
slightly inclined."sett" or vein, with a suitable plastic clay, such as that obtained at

page_text: Newton Abbott in Devonshire, or at Poole in Dorsetshire, according to the colour
and fineness of the goods to be manufactured, and of a certain proportion of calcined
material known as "natural grog." The proportion in which the admixture of
these various materials is made varies with the quality, colour, and fineness of the
goods to be manufactured, and ranges from 10 to 30, or even 40, per cent. of plastic
clay, 50 to 80 per cent. of the decomposed granite or elvan, and 5 to 20 per cent. of
"natural grog."
The decomposed granite or elvan having been ground fine in
admixture with water, is combined or mixed with the plastic clay in suitable pro-
portions, and with the "natural grog " in a suitable vessel, so as to form a paste or
dough, which can then be worked into the required form for terra cotta goods, stone-
ware, and bricks of various kinds. It is then burnt in kilns in the ordinary way,
but, by preference, to a vitrifying heat, so as to give it a non-porous body, and
impermeable to the atmosphere.
Having thus fully described my Invention, and the manner of producing the same,
I wish it to be understood that what I claim and desire to be secured to me by the
herein-before recited Letters Patent is, the improved compound, consisting of decom-
posed granite or elvan and plastic clays, and the application of the same to the
manufacture of terra cotta goods for architectural and ornamental purposes, sub-
stantially as herein-before described or any mere modification thereof."
In witness whereof, I, the said Charles Edward Appleby, have hereunto set
my hand and seal, this Fourth day of December, in the year of our Lord One
thousand eight hundred and seventy-eight.