A NEW METHOD OF GLAZING EARTHENWARE
Year: 1784

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, JOSEPH
CARTLEDGE, of Blackley, in the County of York, Doctor of Physic, sends
greeting.
WHEREAS His present most Excellent Majesty King George the Third,
by His Letters Patent under the Great Seal of Great Britain, bearing
date at Westminster, the Fifth day of February, in the twenty-fourth year
of His reign, reciting that I, the said Joseph Cartledge, had, by my Petition,
humbly represented unto His said Majesty, that I had, by great study,
invented "A NEW METHOD OF GLAZING EARTHENWARE," which would be of public
utility and advantage, and praying His said Majesty to grant unto me, my
exors, adiiors, and assigns, His said Majesty's Letters Patent for the sole
exercise of my said Invention, within England and Wales and the Town of
Berwick-upon-Tweed, for the term of fourteen years from the date of the
said Letters Patent, was graciously pleased to condescend to my request; in
which said Letters Patent is contained a proviso that if I, the said Joseph
Cartledge, should not particularly describe and ascertain the nature of my
said Invention, and in what manner the same is to be performed, by an
instrument in writing under my hand and seal, and cause the same to be
inrolled in His said Majesty's High Court of Chancery within four calendar
months next and immediately after the date of the said Letters Patent, that

page_text: then the sard Letters Patent, and all liberties and advantages whatsoever
thereby granted, should utterly cease, determine, and become void, as in and
by the said Letters Patent, relation being thereunto had, may and will more
fully appear.
NOW KNOW YE, that I, the said Joseph Cartledge, in compliance with
the said proviso, do hereby describe and ascertain the nature of my said
Invention and in what manner the same is to be performed, as follows,
viz:-
First, as to the nature of the Invention, it is well known to the manufac-
turers of carthenware, that all the sorts of common ware now in use are now,
and have been heretofore at all times, both in this and all other countries
I know, glazed either by sea salt, or by lead ore, or by some preparation of
lead, or of lead and tin united to ground flints or clay, or both. Now the
nature of the discovery which I have made consists in this, that instead of
the use of sea salt, or metallic substances, the earthenware is glazed with
various kinds of earths and stones, by which there will be a great saving of
expence in the glazing of the said ware, and the glaze itself, it is apprehended,
will be more perfect than that which is made with salt, and more wholesome
than that into which either lead, or lead and tin, enter as constituent parts.
Secondly, with respect to the manner of applying the earth and stones :-
They are to be ground into powder, and laid on the ware as potters use their
own composition. With respect to the sorts of earths and stones which are
adapted to the purposes they are very various. The toadstone of Derbyshire,
and other places, the Scotch and Guernsey pebbles, the basaltes, and other
productions generally esteemed volcanic, rag stone, slate, shale, granite,
gypsum, fluor spar, marc stone, and many other kinds of earths and stones
which I know not how to denominate, will all, either severally or when
mixed in different proportions with each other, or with siliceous or asgillaceous,
micaceous, or calcareous earths or stones, or with all of them, answer the
purpose. I would have it also understood, that portions of the metallic
substances now used for the purpose of glazing earthenware or saline bodies,
(tho' not necessary for producing the effect) may be used in conjunction with
the earths and stones here mentioned. I would further remark, that the
slags of furnaces, the slags of pit-coal, and the crust which forms on the
bottom slipkilns, by themselves, or in conjunction with the substances before-
mentioned, will glaze earthenware. But as the same effect may be produced by
a great many different sorts of earths and stones, when used either seperately
or when combined in very different proportions, all of which it is impossible
to enumerate or ascertain, I think it fit to mention the three following,

page_text: which have succeeded well with me. Take of Derbyshire toadstone five
parts by weight, fluor spar one part, take thirty-three parts of clay, nineteen
parts of flint, thirty-eight parts of striated gypsum, take fluor spar one, two,
three or four parts, porcelain clay two parts, siliceous earth one fourth of a part,
of calcareous earth one sixth of a part.
In witness whereof, I, the said Joseph Cartledge, have hereunto set my
hand and seal, this Twenty-first day of May, One thousand seven
AND BE IT REMEMBERED, that on the Twenty-first day of May, in
the year of our Lord 1784, the aforesaid Joseph Cartledge came before
our said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stampt according
to the tenor of the Statutes made for that purpose.
JOHN RICHARDS.
AND BE IT REMEMBERED, that on the Twenty-first day of May, in
the year of our Lord 1784, the aforesaid Joseph Cartledge came before
our said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stampt according
to the tenor of the Statutes made for that purpose.
Inrolled the Twenty-first day of May, in the year of our Lord One
thousand seven hundred and eighty-four.