IMPROVEMENTS IN GLAZING STONEWARE, RED CLAYWARE, PORCELAIN, AND OTHER KINDS OF EARTHEN- WARE
Year: 1862

page_text: LETTERS PATENT to John Cliff, of the Imperial Potteries, Lambeth, in
the County of Surrey, for the Invention of "IMPROVEMENTS IN GLAZING
STONEWARE, RED CLAYWARE, PORCELAIN, AND OTHER KINDS OF EARTHEN-
WARE."
Sealed the 22nd August 1862, and dated the 26th February 1862.
PROVISIONAL SPECIFICATION left by the said John Cliff at the Office of
the Commissioners of Patents, with his Petition, on the 26th February
1862.
I, JOHN CLIFF, of the Imperial Potteries, Lambeth, in the County of
Surrey, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN GLAZING STONEWARE, RED CLAYWARE, PORCELAIN, AND OTHER KINDS OF
EARTHENWARE," to be as follows:-
This Invention relates to the glazing of various kinds of earthenware by a
method not hitherto adopted for such purpose.
It is well known that in the ordinary method of salt glazing the flame from
the furnace is introduced amongst the pottery ware, which flame carries with
it particles of dirt or dust, thus imparting to the ware an unclean glazed
surface.
Now I propose to employ, in lieu of the ordinary furnace for glazing
pottery, an oven or kiln heated by flames or jets of gas, which are caused to
decompose salt placed among or near the pottery ware, by which means salt
gas is generated and circulated throughout the kiln, communicating to the
ware a clean clear glaze.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Cliff in the Great Seal Patent Office on the 26th
August 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Jonn
CLIFF, of the Imperial Potteries, Lambeth, in the County of Surrey, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of February, in the year of our
Lord One thousand eight hundred and sixty-two, in the twenty-fifth year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Cliff, Her special licence that I, the said John Cliff, my
exccutors, administrators, and assigns, or such others as I, the said John Cliff,
my executors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain, and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN GLAZING STONE-
WARE, RED CLAYWARE, PORCELAIN, AND OTHER KINDS OF EARTHENWARE," upon
the condition (amongst others) that I, the said John Cliff, my executors or
administrators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said John Cliff, do hereby declare the nature
of my said Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This Invention relates to the glazing of various kinds of ware by a method
not hitherto adopted for such purpose.
In order to explain my said Invention as completely as possible I now
proceed to describe the best means I am acquainted with for carrying the
same into practical effect, as follows:-
It is well known that in the ordinary method of salt glazing the flame and
other products of combustion from the furnace are introduced amongst the
goods and carry with them particles of ferruginous and other fine ash or dust,
which being deposited on the goods impart to the articles glazed a variously
colored surface, according to the quantities and qualities of the deposits.

page_text: Now my Invention consists in using, in lieu of the ordinary kiln with open
fires, ovens, furnaces, or chambers, for glazing goods, an oven or kiln heated
by flames or jets of gas, thus generating heat without deposition of ash or dust
on the goods. When-such furnace is sufficiently heated, common salt, metals,
salts, or other glazing materials or agents, may be applied directly amongst
the goods, or slabs or open saggers containing the goods, in the ordinary
manner, namely, in at the furnace mouths or by scattering from orifices in the
top or sides of said furnaces; or, if more convenient, the gases, fumes, or
vapours, may be generated in separate producers or furnaces and the resulting
products conveyed by flues or pipes into the furnace and amongst the goods to
be glazed, thus, in the absence of deposits referred to, securing a transparent
glaze and uniform color, the color of the body of the ware regulating the
latter.
Having now described the nature of my said Invention of " 'Improvements
in Glazing Stoneware, Red Clayware, Porcelain, and other Kinds of Earthen-
ware, I would remark, in conclusion, that I do not confine myself to any
particular kind of furnace for generating the desired heat, nor to any par-
ticular description of salt of which the gases or vapours are to be composed,
as in practice the salts may be varied to suit the particular description of
goods to be glazed, but what I claim as my Invention and desire to be secured
to me by the herein in part recited Letters Patent is, the glazing earthenware
in furnaces or ovens heated by gas to the proper temperature for decomposing
the glazing materials introduced and applied to the goods, as above described.
In witness whereof, I, the said John Cliff, have hereunto set my hand
and seal, this Twenty-fifth day of August, One thousand eight hundred
and sixty-two.
JOHN CLIFF. (L.S.)
Witness,
S. J. WETHERELL,
Clerk to Messrs. Prince, Hammond, & Prince,
Agents for Patents,
4, Trafalgar Square,
Charing Cross.