IN IMPROVED PROCESS FOR MANUFACTURING CARBONATE OF LEAD, COMMONLY CALLED WHITE LEAD
Year: 1838

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
WOOLRICH, of Birmingham, in the County of Warwick, Professor of Chemistry,
send greeting.
WHEREAS I did by petition represent unto Her most Excellent Majesty
Queen Victoria, that I had invented "IN IMPROVED PROCESS FOR MANUFACTURING
CARBONATE OF LEAD, COMMONLY CALLED WHITE LEAD;" and whereas Her Majesty
by Her Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Eleventh day of October, in the second year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John Woolrich, Her especial licence, that I, the said John Woolrich, my
exors, adiñors, and assigns, or such others as I, the said John Woolrich, my
exors, adñiors, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, the said Invention; in which
said Letters Patent is contained a proviso obliging me, the said John Woolrich,
by an instrument in writing under my hand and seal, particularly to describe
and ascertain the nature of the said Invention, and in what manner the same
is to be performed; and to cause the same to be enrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Woolrich, do hereby declare the nature of the said Invention to consist

page_text: in making or producing carbonate of lead, commonly called white lead, by
forming from the friction of the ordinary lead of commerce, moistened with
such solution as herein-after described, or one of such solutions as herein-
after mentioned, a product convertible into carbonate of lead or white lead, by
the passing carbonic acid gas through such product and fluid, as herein-after
mentioned, and separating such product converted into carbonate of lead or
white lead from such fluid, and drying such carbonate of lead or white lead.
And in further compliance with the said proviso,. I, the said John Woolrich,
do hereby describe the manner in which the said Invention is to be performed
by the following statement (that is to say) :-
I first divide the ordinary lead of commerce into small pieces, about the size
of grains of barley, by melting it and running it in that state through a
metallic sieve into water. I place the lead, reduced into such small pieces as
aforesaid, in a cylindrical, or in preference an bexagonal vessel, which I
prefer to be made of lead or earthenware; vessels of other forms and made
of other substances may be used, but I prefer those above described; at the
centre of each end of such vessel is a hole about one-sixth the diameter of the
vessel, but the precise size is immaterial, and a small copper grating is fixed.
at the extremity of the side of such cylindrical vessel, or at the extreme end of
one of the sides of such hexagonal or other vessel, and extending nearly across
the whole of such side, but the precise size is immaterial; pieces of lead,
reduced to such size as aforesaid, are put into such cylindrical or hexagonal
or other vessel in such quantity as not to run out of such holes as aforesaid:
on such vessels being turned as hereafter mentioned; I then moisten the
small pieces of lead with the following solution, videlicit, protoxide of lead
dissolved in dilute acetic acid in such proportions as completely to neutralize
the acid, and to render the solution of specific gravity about 1.60. A small
variation in the specific gravity of the solution is not material, but I prefer it
to be of the specific gravity herein-before mentioned. I fix the vessel, in
which are such pieces of lead as aforesaid, moistened with such solution as
aforesaid, in a horizontal position, and so as to be capable of being turned
round by machinery, or such vessel, with other similar vessels, may be made to
turn round by the application of the ordinary mechanical powers. The aforesaid
pieces of lead in such vessel or vessels must be kept continually moistened
with such solution as aforesaid. The turning round of such vessel or vessels
causes a friction of such pieces of lead, moistened as aforesaid, and therefrom.
gradually is formed a product easily separated by washing, as herein-after-
mentioned, from the portions of such pieces of lead as are not formed into
such product. The product thus gradually formed I wash away every twelve.

page_text: hours from the particles of metallic lead, and remove from such vessel or
vessels, by a jet of such solution as aforesaid, mixed with water; the quantity:
of the solution and water and the proportions of the solution and water used
in the washing process are immaterial; and I add fresh quantities of the pieces
of lead, so as to keep up the original quantity of metal in the vessel or vessels.
I place the product aforesaid, with the fluid used in washing the same away'
from such vessel or vessels as aforesaid, in another closed vessel, where such
product and fluid are kept in motion by a spindle constantly moving round in
such vessel; and through such vessel I pass carbonic acid gas made by
drawing air through a charcoal fire, the result is carbonate of lead or white:
lead, suspended in fluid; carbonic acid gas may also be made by various other
well-known processes, but I prefer the one I have described. The carbonate
of lead or white lead may be easily separated from the fluid in which it has
been suspended by permitting it to settle for a few hours, when the carbonate
of lead or white lead will fall to the bottom of the vessel, and the fluid may
be drawn off by means of a syphon, or the carbonate of lead or white lead
may be separated from the fluid by filtration; it is then dried in the ordinary
way, and is then fit for use. Other solutions may be used instead of the
solution above described, videlicit, a solution of protoxide of lead dissolved in
dilute nitric acid, or a solution of acetate of lead in water, or a solution of
nitrate of lead in water, or a solution of the carbonate of potash in water, or a
solution of carbonate of soda in water. When a solution of carbonate of potash
in water or a solution of carbonate of soda in water is used, the proportions
are about one part by weight of the carbonate to ten parts by weight of water.
A solution of acetic acid and water forming dilute acetic acid, or a solution of
nitric acid and water forming dilute nitric acid, may also be used without being.
previously combined with protoxide of lead, and any one of such solutions may
be used in lieu of the solution of protoxide of lead and dilute acetic acid.
firstly herein-before described; but I prefer the solution firstly herein
described. At the same time I claim the use of all or any of such solutions
with metallic lead, in the manner herein-before described. The vessel I
ordinarily use is hexagonal, twenty inches in diameter and five feet long, with
a round hole from three to four inches in diameter, exactly in the centre of
each end.thereof; a small copper grating, perforated with a number of small
holes, is placed at the extremity of any one of the sides; the fluid used in the
washing away the product as aforesaid, with such produce, passes through
such grating; in such vessel I ordinarily place from about eight to ten cwt.
of such pieces of lead as aforesaid.
And whereas I do not. claim as my Invention the mode of reducing such

page_text: ordinary lead of commerce to pieces of such size as aforesaid, or the form or
materials of such vessels as aforesaid, or the mode of obtaining carbonic acid gas,
or of separating or drying; but I do claim as my Invention, the forming, from
the friction of the ordinary lead of commerce, moistened with any of such
solutions as herein-before mentioned, a product convertible into white lead
or carbonate of lead, by the passing carbonic acid gas through such product
and fluid, as berein-before mentioned, and then separating and drying such
product converted into carbonate of lead or white lead.
And such Invention being to the best of my knowledge and belief entirely
new, and never before used within that part of Her said Majesty's United
Kingdom of Great Britain and Ireland called England, Her said Majesty's
Dominion of Wales, or the Town of Berwick-upon-Tweed, I do hereby declare
this to be my Specification of the same, and that I do verily believe that this my
Specification doth comply in all respects fully and without reserve or disguise
with the said proviso in the herein-before in part recited Letters Patent con-
tained; wherefore I do hereby claim and maintain exclusive right and privilege
to my said Invention.
In witness whereof, I, the said John Woolrich, have hereunto set my
hand and seal, this Tenth day of April, in the year of our Lord One
thousand night hunded and thinte mi