A PARTICULAR METHOD OF MANUFACTURING CERTAIN MATERIALS FOUND OUT AND DISCOVERED BY ME INTO CRUCIBLES, COMMONLY KNOWN BY THE NAME OF BLACK LEAD CRUCIBLES
Year: 1769

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GoUSSE
BONNIN, late of Boveney, in the County of Bucks, Gentleman, send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of Great Britain, bearing date the '
Fifth day of May, in the ninth year of His reign, did give and grant unto me,
the said Gousse Bonnin, His especial licence, that I, the said Gousse
Bonnin, during the term of years therein expressed, should and lawfully
night use, exercise, and vend, within England, Wales, and Town of Ber-
wick-upon-Tweed, and also within all His Majesty's Colonies and Plan-
tations abroad, my Invention of "A PARTICULAR METHOD OF MANUFACTURING
CERTAIN MATERIALS FOUND OUT AND DISCOVERED BY ME INTO CRUCIBLES, COMMONLY
KNOWN BY THE NAME OF BLACK LEAD CRUCIBLES," which upon tryal have been
found greatly superior to any of that name hitherto imported from Germany"
by the way of Holland; in which said Letters Patent there is contained a
provisoe, obliging me, the said Gousse Bonnin, under my hand and seal, to
cause a particular description of the nature of my said Invention, and how the
the same is to be performed, to be inrolled in His Majesty's High Court of
Chancery within four calendar months after the date of the said recited
Letters Patent, as in and by the same (relation being thereunto had), inay
more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Gousse Bonnin, do hereby declare that my said Invention of a particular
Method of Manufacturing certain Materials found out and discovered by me

page_text: into Crucibles, commonly known by the Name of Black Lead Crucibles, is
described in the manner following, that is to say:-
Of a species of clay hitherto only discovered near the city of Philadelphia,
in the province of Pensylvania, in America, one equal part, which must lie
twenty hours in water to cleanse it from its impurities before it is fit for use;
of unadulterated black lead an equal part, which must be carefully pounded
in a wooden morter, and sifted through an horse-hair sieve to prevent the stony
particles inherent to black lead passing with it, which particles, being of a
spungey nature, and vitrifying in extreme heat, effectually destroy the crucibles.
Thus prepared, take the equal parts of lead and clay, and mix them thoroughly
together, softening them occasionally with warm water, and let them lie twenty
hours thus mixed before used, as the lead requires some time thoroughly
to engender with the clay. Of this mixture or cement the crucibles are
formed upon a common potter's wheel in the same manner as glazed and
other pots, and undergo the same operation of heat to harden them. It is
easy to discover any flaw in the crucibles by sounding them, as is customary
with china. It is by this method also it is to be judged whether they are
sufficiently hardened. As no general rule can convey an adequate knowledge
of quality and composition, it requires practice to endue the manufacturer with
a true sense of the clay or lead, since if the clay is of inferior quality, more
clay and less lead are required, so vice versa.
In witness whereof, I, the said Gousse Bonnin, have hereunto set my
hand and seal, this Twenty-fifth day of July, One thousand seven
Inrolled the Twenty-seventh day of July, in the year above written.