A NEW COMPOUND OF LEAD, APPLICABLE TO THE PURPOSES FOR WHICH WHITE LEAD AND RED LEAD ARE EMPLOYED, AND THE PROCESS OF PRODUCING SUCH COMPOUND FROM GALENA
Year: 1874

page_text: LETTERS PATENT to Jules David, of No. 50, Rue Saint Anne, Paris,
in the Republic of France, for the Invention of "A NEW COMPOUND
OF LEAD, APPLICABLE TO THE PURPOSES FOR WHICH WHITE LEAD AND RED
LEAD ARE EMPLOYED, AND THE PROCESS OF PRODUCING SUCH COMPOUND FROM
GALENA."
Scaled the 2nd October 1874, and dated the 27th April 1874.
PROVISIONAL SPECIFICATION left by the said Jules David at the
Office of the Commissioners of Patents, with his Petition, on the
27th April 1874.
I, JULES DAVID, of No. 50, Rue Saint Anne, Paris, in the Republic
5 of France, do hereby declare the nature of the said Invention for "A
NEW COMPOUND OF LEAD, APPLICABLE TO THE PURPOSES POR WHICH WHITE LEAD
AND RED LEAD ARE EMPLOYED, AND THE PROCESS OF PRODUCING SUCH COMPOUND
FROM GALENA," to be as follows:-
:―

page_text: term "galenite" from sulphuret of lead. For this purpose lead ore or
galena from which the gangue has been removed is completely oxidized
in retorts similar to those used for the manufacture of coal gas. This
oxidation is effected at a dark red heat. The ore being reduced to a
coarse powder is spread out in a layer of about half an inch in thickness
upon fire-clay slabs, if the retort is of iron, or on the retort itself if this
is of fire-clay. Air is allowed to pass freely through the retorts, which
have openings for this purpose. During this process of roasting the ore,
considerable quantities of sulphurous acid vapour are disengaged, which
may either be utilized or allowed to pass away.
The process of oxidation lasts about 20 hours. Too great a heat should
not be applied after the commencement of the operation in order that
the galena may not be fused; the oxidation should be allowed to take
place slowly.
It is not necessary to stir or mix the material as in the smelting of
lead.
The layer of galena being oxidized on its upper surface becomes
formed into a cake, which should be turned over at the end of about
10 hours by means of a long shovel, in order to effect the oxidation of
the lower surface, and when the mass has thus been entirely oxidised,
which is ascertained by the cessation of the sulphurous acid ſumes, it is
removed from the retort in order to be ground. In this condition the
oxidised galena is the result of the combination of one equivalent of
sulphate of lead with one equivalent of oxide of lead. It is a true
bibasic sulphate to which I have given the name of " galenite."
"
.
The grinding of the mass is effected between grindstones similar to
those used for flour mills immersed in a vessel filled with water. The
galenite" passes from a hopper into the eye of the millstones, and is
ground between these in contact with water. This grinding process
lasts at least ten hours; at the end of this time a liquid is obtained of a
brownish yellow colour, or if the oxidation has not been quite perfect, of
an ashy grey colour. This liquid is placed in vats and the suspended
matter is allowed to deposit, which takes more or less time according to
the degree of fineness to which the mass has been ground. Ordinarily,
the precipitation is completed in about one hour. The deposit is then
removed and dried, when it constitutes the "galenite" and is ready for

page_text: use. If the mass is of a grey colour it still contains some sulphuret of
lead. It should in this case be again subjected to a low red heat during
about two hours in open retorts, until it assumes the proper yellow
colour.
When mixed with pure linseed or poppy seed oil, the "galenite" forms
a rich pigment of a very siccative nature. When spread on wood, plaster,
or stucco it covers the surface better than white lead, and it is of an
exceedingly adhesive and tenaceous nature. It coats metals and
preserves them from oxidation as effectually as red lead, and may be
used in making pipe joints and other metal joints; it is also applicable
in the production of acetates of lead in the same way as other load
compounds.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Jules David in the Great Seal Patent Office on
the 16th October 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JULES
DAVID, of No. 50, Rue Saint Anne, Paris, in the Republic of France,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of April in the year
of our Lord One thousand cight hundred and seventy-four, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Jules David, Her special
license that I, the said Jules David, my executors, administrators,
and assigns, or such others as I, the said Jules David, my exc-
cutors, 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 make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for “A New Com-
POUND OF LEAD, APPLICABLE TO THE PURPOSES FOR WHICH WHITE LEAD AND RED
LEAD ARE EMPLOYED, AND THE PROCEss op Producing such Compound from Galena,”
upon the condition (amongst others) that I, the said Jules David, my

page_text: sulphate of lead with one equivalent of oxide of lead. It is a true
bibasic sulphate to which I have given the name of "galenite."
The grinding of the mass is effected between grindstones similar to
those used for flour mills immersed in a vessel filled with water. The
galenite passes from a hopper into the eye of the millstones, and is
ground between these in contact with water. This grinding process
lasts at least ten hours. At the end of this time a liquid is obtained of
a brownish yellow colour, or if the oxidation has not been quite perfect
of an ashy grey colour. This liquid is placed in vats and the suspended
matter is allowed to deposit, which takes more or less time, according to
the degree of fineness to which the mass has been ground. Ordinarily,
the precipitation is completed in about one hour. The deposit is then
removed and dried, when it constitutes the "galenite" and is ready
for use.
If tlic mass is of a grey colour it still contains some sulphuret
of lead. It should in this case be again subjected to a low red heat
during about two hours in open retorts until it assumes the proper yellow
colour.
"
When mixed with pure linseed or poppy seed oil the galenite" forms
a rich pigment of a very siccative nature. When spread on wood,
plaster, or stucco it covers the surface better than white lead, and it is of
an exceedingly adhesive and tenacious nature. It coats metals and
them from oxidation as effectually as red lead, and
preserves
may
used in making pipe joints and other metal joints; it is also applicable
in the production of acetates of lead in the same way as other lead
compounds."
be
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I claim,-
First. The before described new substance termed "galenite" pro-
duced from sulphuret of lead.
Second. The preparation of the said new substance from sulphuret of
lead by the process hercin described.
Third. The application of the said new substance to all purposes for
which red lead and white lead are used, such as for painting, for pipe
and other metal joints, for mastics, for coating plaster, cement, and
stucco to protect the walls against moisture, for the manufacture of

page_text: acetates of lead, and for all other purposes to which the galenite is
applicable.
In witness whereof, I, the said Jules David, have hereunto set my
hand and seal, this Twelfth day of October, in the year of our
Lord One thousand eight hundred and seventy-four.