IMPROVE. MENTS IN THE MANUFACTURE OF WHITE LEAD
Year: 1876

page_text: LETTERS PATENT to Norman Charles Cookson, of the Town and County of
Newcastle-upon-Tyne, Lead Manufacturer, for the Invention of "IMPROVE.
MENTS IN THE MANUFACTURE OF WHITE LEAD."
Sealed the 21st July 1876, and dated the 19th February 1870.
PROVISIONAL SPECIFICATION left by the said Norman Charles Cookson at
the Office of the Commissioners of Patents on the 19th February 1876.
NORMAN CHARLES COOKSON, of the Town and County of Newcastle-upon-Tyne,
Lead Manufacturer. "IMPROVEMENTS IN THE MANUFACTURE OF WHITE LEAD.'
I manufacture white lead by the exposure of a solution of sub-acetate of lead to
the action of carbonic acid gas, and my Invention consists in the manner of the
preparation of such solution of sub-acetate of lead for such process, namely, I take
à solution of acetate of lead, either pure or containing any insufficient quantity of
sub-acetate, and I add to it an oxide of lead (or litharge), the effect being that the
solution is prompty brought by the decomposition of the oxide of lead and the
formation of an equivalent quantity of sub-acetate into a condition to be advan-
tageously used for the manufacture of white lead by the process referred to.
The solution of pure acetate of lead, or of mixed acetate and sub-acetate in
insufficient proportion and the oxide of lead separately may be made in any con-
venient manner.
What I claim is, the admixture above described as an improvement in the
manner of the preparation of the solution to be operated upon in the manufacture
of white lead.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Norman Charles Cookson in the Great Seal Patent Office on the
18th August 1876.
NORMAN CHARLES COOKSON, of the Town and County of Newcastle-upon-Tyne,
Lead Manufacturer. "IMPROVEMENTS IN THE MANUFACTURE OF WHITE LEAD."
I manufacture white lead by the exposure of a solution of sub-acctate of lead to
the action of carbonic acid gas, and my Invention consists in the manner of the
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page_text: preparation of such solution of sub-acetate of lead for such process; namely, I take
a solution of acetate of lead, either pure or containing any insufficient quantity of
sub-acetate, and I add to it an oxide of lead or litharge, the effect being that the
solution is promptly brought by the decomposition of the oxide of lead and the
formation of an equivalent quantity of sub-acetate into a condition to be advan-
tageously used for the manufacture of white lead by the process referred to.
The solution of pure acetate of lead, or of mixed acetate and sub-acetate in
insufficient proportion, and the oxide of lead separately may be made in any con-
venient manner.
I prefer to take a saturated or nearly saturated solution of acetate of lead, and I
mix it in a vat provided with a mechanical agitator with an excess of litharge;
afterwards I allow it to settle until the liquor becomes clear, and then I draw off the
liquor for use; I then proceed to treat this solution with carbonic acid gas to
precipitate white lead from it. I prefer to convert the solution of sub-acetate to
the state of spray, and when it is in this state to submit it to the action of the gas
in the manner described in the Specification of a Patent No. 708, bearing even date
with the Patent of which the present is the Specification.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that I claim, the manufacture of
white lead by treating a solution of the acetate of lead with oxide of lead or
litharge, and then submitting the solution of sub-acetate so obtained to the action
of carbonic acid gas in such manner as to precipitate white lead as described.
In witness whereof, I, the said Norman Charles Cookson, have hereunto set
my hand and seal, this Fifteenth day of August, in the year of our Lord One
thousand eight hundred and seventy-six.