IMPROVEMENTS IN THE MANUFACTURE OF WHITE LEAD
Year: 1867

page_text: LETTERS PATENT to William Robert Lake, of the "International Patent
Office," No. 8, Southampton Buildings, Chancery Lane, in the County
of Middlesex, Consulting Engineer, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF WHITE LEAD."-A communication from abroad by
Thomas Mara Fell and Ambrose George Fell, both of the City, County,
and State of New York. United States of America.
Sealed the 15th November 1867, and dated the 17th May 1867.
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition, on the
17th May 1867.
I, WILLIAM ROBERT LAKE, of the "International Patent Office," No. 8,
Southampton Buildings, Chancery Lane, in the County of Middlesex, Con-
sulting Engineer, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN THE MANUFACTURE OF WHITE LEAD," a communication, to be as
follows:-
White lead made in the ordinary way is expensive because of the long and
tedious process necessary in producing it, and when obtained is of a dark
color, because it contains free metallic lead. With the following improved
process a pure white color as well as a much cheaper white lead is obtained

page_text: which is of a good quality. Sulphate of lead and carbonate of baryta in the
proportion of one hundred parts by weight of carbonate of baryta to every one
hundred and fifty-two parts of sulphate of lead are placed in a vessel to which
water is added, the mixture being stirred until it is all. reduced to a thin
paste; after it has been well combined by thorough stirring the said mixture
is well heated for three or four hours to a temperature of about one hundred
and sixty degrees Fahrenheit, though this temperature may be considerably
reduced or may be raised up to near the boiling point without materially
affecting the result, the stirring--being- continued during this.. part of the
process. This process will cause the following interchange of elements to
take place, namely, the sulphuric acid of the sulphate of lead combines with
the baryta forming sulphate of baryta, and liberating carbonic acid which
unites with the lead and forms carbonate of lead; this is then dried in the
ordinary way. The compound thus produced is similar to the ordinary white
lead, but with this advantage that the baryta is formed in it and is con-
sequently more thoroughly mixed and combined therewith. The baryta being
also. chemically, formed in the lead the latter is much finer in texture than
could be rendered by any mechanical manipulation or means. Other salts of
lead (carbonates excepted) may be substituted for sulphate of lead, but the
-sulphate gives superior results.
SPECIFICATION in pursuance of the conditions of the Letters Patent,,filed
by the said William Robert Lake in the Great Seal Patent Office on the
'16th November 1867.
TO ALL TO WHOM THESE, PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the "International Patent Office," No. 8, Southampton
Buildings, Chancery Lane, in the County of Middlesex, Consulting Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by. Her Letters
"Patent, bearing date the Seventeenth day of May, in the year of our Lord One
"thousand eight hundred and sixty-seven, in the thirtieth year of Her reign,
'did, for Herself, Her heirs and successors, give-and-grant-unto-me, the
said William Robert Lake, Her special licence that I, the said- William
Robert Lake, my executors, administrators, and assigns, or such others as I,
the said William Robert Lake, my executors, administrators, - and assigns,
should' at any time agree with, and no others, from time to time and at all
*times thereafter during the term therein expressed, should and lawfully might

page_text: make, use, exercise, and vend, within, the United Kingdom of Great Britain
and Ireland, the Channel Islands; and Isle of Man, an Invention of "In
PROVEMENTS IN THE MANUFACTURE OF, WHITE. LEAD," upon the condition (amongst
others), that I, thé said: William. Robert Lakė, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Invention, and
in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said. Letters.Patent.
NOW KNOW YE, that I, the said. 'William Robert Lake, do hereby
declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement :-
White lead made in the ordinary way is expensive because of the long and
tedious process necessary in producing it, and when obtained is of a dark
colour because it contains free metallic lead. With the following improved
process & pure white colour as well as a much cheaper white lead is obtained,
which is of a good quality.
In order to obtain this white lead I proceed as follows:-Sulphate of lead
and carbonate of baryta in the proportion of one hundred parts by weight of
carbonate of baryta to every one hundred and fifty-two parts of sulphate of
lead are placed in a vessel, to which water is added, the mixture being stirred
until it is all reduced to a thin paste; after it has been well combined by
thorough stirring the said mixture is well heated for three or four hours to a
temperature of about one hundred and sixty degrees Fahrenheit, though this
temperature may be considerably reduced or may be raised to nearly the boiling
point without materially affecting the result. The stirring is continued
during this part of the process. This treatment will cause the following
interchange of elements to take place, namely, the sulphuric acid of the
sulphate of lead combines with the baryta, forming sulphate of baryta, and
thus liberates carbonic acid which unites with the lead forming carbonate
of lead; this is then dried in the ordinary way. The compound thus produced
it will be seen is similar to the ordinary white lead, but with this advantage
that the baryta is formed in it and is consequently more thoroughly mixed
and combined therewith; the baryta being also chemically formed in the
lead the same is much finer in texture than it could be rendered by any
mechanical means. Other salts of lead, carbonates excepted, may be substi-
tuted for sulphate of lead, but with the latter superior results are obtained.

page_text: Having thus fully described the said improvements as communicated to 'me
by my foreign correspondents, and shown how the same may be conveniently
and advantageously carried into practice, I claim, the treatment of salts
of lead and the carbonate of .baryta in the manner and for the purpose
substantially as herein described.
In witness whereof, I, the said William Robert Lake, have hereunto
set my hand and seal, this Sixteenth day of November, in the year of
our Lord One thousand eight hundred and sixty-seven.
WILLIAM ROBERT LAKE. (LB.)
Witness,
THO. N. PALMER,
Clerk to Messrs. Haseltine, Lake, & Co.,
8, Southampton Buildings, W.C.