IMPROVEMENTS IN THE MANUFAC- TURE OF WHITE LEAD
Year: 1849

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JULIAN
EDWARD DISBROWE RODGERS, of High Street, Pimlico, in the County of
Middlesex, Professor of Chemistry, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the First day of August,
One thousand eight hundred and forty-nine, in the thirteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the Julian Edward Disbrowe Rodgers, my exors, adñiors, and assigns, Her
especial licence, full power, sole privilege and authority, that I, the said
Julian Edward Disbrowe Rodgers, my exors, adiññors, and assigns, and such
others as I, the said Julian Edward Disbrowe Rodgers, my exors, admors, 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 Invention of "IMPROVEMENTS IN THE MANUFAC-
TURE OF WHITE LEAD," communicated to me from abroad; in which said
Letters Patent is contained a proviso that I, the said Julian Edward Disbrowe
Rodgers, should cause a particular description of the nature of the said Inven-
tion, and in what manner the same is to be performed, by an instrument in
writing under my hand and seal, to be iurolled in Her said Majesty's High
Court of Chancery within six calendar months next and immediately after
the date of the said in part 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
Julian Edward Disbrowo Rodgers, do hereby declare that the nature of the

page_text: said Invention, and the manner in which the same is to be performed, are
fully described and ascertained in. and by the following statement thereof,
that is to say:-
The Invention of improvements in the manufacture of the carbonate of lead,
known as the pigment white lead, consists in exposing metallic lead to the
united influence and action of a certain temperature, atmospheric air, aqueous
and acetic acid or pyroligneous acid vapors, and carbonic acid gas, in such a
manner as to have the process of conversion completely under the control of
the operator. I employ a room or chamber capable of being heated by steam
pipes, flues, or other means, and so constructed as to allow of its being made
dark, air-tight, or nearly so, and to permit the escape of gases and vapors
when such is necessary. In this room or chamber wooden frames are fitted
from the ceiling to the floor (or other convenient means), with cross pieces of
the same material, for the purpose of supporting the lead, and so arranged
that a man may pass between the rows to watch and regulate the progress of
its conversion into white lead. Vessels or troughs are placed upon or let in
the floor, some to contain a fluid undergoing the vinous fermentation, and thus
to supply carbonic acid gas, while others (into which pipes communicating
'with a steam boiler and furnished with stopcocks pass) are to contain weak
vinegar, dilute pyroligneous acid, sour beer, acid wine, or a liquid undergoing
the acetous fermentation, in order to supply vapors of acetic acid by means
presently to be mentioned. I operate as follows:-Having bent lead, cast in
sheets three or four feet long and about one eighth of an inch thick, thus A,
'I hang them on the wooden frames as closely as possible without touching. I
then put into the vessels or troughs furnished with pipes weak vinegar, dilute
pyroligneous acid, sour beer, acid wine, or a liquid undergoing the acetous
fermentation, and into the others an infusion of malt with
sugar in the pro-
portion of about one peek of malt with two pounds of sugar to eight gallons
of boiling water or other liquid capable of undergoing. the vinous fermentation
spontaneously, or when mixed with yeast or other ferment.
If the tempera-
ture of the room or chamber be not above seventy degrees Fahrenheit, I raise
it by means of the steam pipes-or-flues until it is between seventy and eighty
degrees Fahrenheit. When the vinous fermentation is fully established, and
carbonic acid gas is being evolved into the room or chamber, I darken and
close it as perfectly as possible, and then pass steam from the boiler into the
acid liquor, so as to charge the room or chamber with aqueous and acetic acid
vapors. The passage of steam must continue for about an hour, and be
repeated three or four times in twenty-four hours. The temperature must be
kept between seventy and eighty degrees, and is easily observed by having a

page_text: thermometer so placed that while its bulb is in the room or chamber its stem
is outside. It is necessary to enter the room once in about every forty-eight
hours during the progress of conversion (which is usually complete in about
twelve days), to renew the fermenting and acid liquids.
I do not confine myself to any particular form of room or chamber, nor do
I confine myself to the use of lead cast in sheets; but I prefer the lead so
prepared, as it is more easily acted on. Nor do I confine myself to fermenta-
tion alone as the source of the necessary carbonic acid gas, as the action of
certain acids on chalk, marble, and other carbonates, the combustion of coke,
charcoal, and of other substances rich in carbon, would yield an abundant
supply; but I prefer it, as such a liquid as I have already mentioned rapidly
passes from the vinous to the acetous fermentation, and may then be
economically employed to furnish the acetic acid vapors, instead of using
vinegar or pyroligneous acid.
I claim as the Invention in the manufacture of white lead,-
First, the use of a room or chamber such as I have described, or one con-
structed upon the same principle, whatever may be the form, videlicet:-One
capable of being rendered air-tight, or nearly so, when necessary, and. into
which the supply of carbonic acid gas and acetic acid, or pyroligneous acid and
aqueous vapors, can be controlled or regulated.
Second, I claim the introduction of steam into the converting chamber,
cither alone or in the manner already mentioned.
In witness whereof, I, the said Julian Edward Disbrowe Rodgers, have
hereunto set my hand and seal, this Twenty-ninth day of January, in
the year of our Lord One thousand eight hundred and fifty.
JULIAN EDWARD DISBROWE (L.S.) RODGERS.
AND BE IT REMEMBERED, that on the Twenty-ninth day of January, in
the year of our Lord 1850, the aforesaid Julian Edward Disbrowe Rodgers came
before our said Lady the Queen in Her Chancery, and acknowledged the Speci-
fication aforesaid, and all and every thing therein contained and specified, in
form above written. And also the Specification aforesaid was stamped accord-
ing to the tenor of the Statute made for that purpose.
Enrolled the Thirtieth day of January, in the year of our Lord One
Leicht hundred and filt