CERTAIN IMPROVEMENTS IN MAKING PAINT OR PIGMENT, BY PREPARING AND COMBINING A SUBSTANCE OR MATERIAL WITH OIL OR TURPENTINE OR OTHEE INGREDIENTS
Year: 1826

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETE
GROVES, of Liverpool Street, in the City of London, Esquire, send greeting.
WHEREAS His present most Excellent Majesty King George the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date af
Westminster, the Tenth day of July, One thousand eight hundred and twentya
six, in the seventh year of His reign, did, for Himself, His heirs and successors,
give and grant unto me, the said Peter Groves, His especial licence that I,
the said Peter Groves, my exors, adñors, and assigns, or such others as I, the
said Peter Groves, my exors, adñiors, or assigns, should at any time agres
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, and also
in all His said Majesty's Colonies and Plantations abroad, my Invention of
"CERTAIN IMPROVEMENTS IN MAKING PAINT OR PIGMENT, BY PREPARING AND
COMBINING A SUBSTANCE OR MATERIAL WITH OIL OR TURPENTINE OR OTHEE
INGREDIENTS;" in which said Letters Patent is contained a proviso, obliging
me, the said Peter Groves, by an instrument in writing tinder my hand and
seal, particularly to describe and ascertain the nature of my said Invention,
and in what manner the same is to be performed, and to cause the same to be
inrolled in His 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 n
large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Peter Groves, do hereby declare that the nature of my said I nvention, and the
manner in which the same is to be performed, are particularly described and
ascertained in the following description thereof (that is to say) :—
My improvements consist in two ways or methods of making paint or
pigment from sulphuret of lead, commonly called galena, or lead 'ore, differently
from any other person. I either make it from lead ore without smelting, or
I smelt the ore, as is usually done in Derbyshire and other places, and run
out the lead and the slag separate, and I take the slag thus run to make into
paint, which has not been done heretofore.
I will first describe the method and process of making paint or pigment
from lead ore without smelting it. I take half a ton of galena or lead ore
and break it very small with hammers or stampers, and afterwards reduce it
to a fine powder in a crushing mill or a mortar; I then burn or roast it,
taking care not to apply so much beat as to melt it; when cold I grind it and
wash it in vats or tubs, so as to float off the fine particles and grind the coarse
ones over again, proceeding thus till the whole is ground very fine; I then
dry it in pans in a kiln or heated room or in the open air; when dried
I reduce it again to a powder, and mix it with two hundred and fifty pounds
of nitrate of potash, or nitre, commonly called saltpetre. This mixture is put
into a vessel which I call a retort, and which I have described, as well as this
part of the process, in the Specification of the Patent for making white lead,
dated the Fourth day of July, One thousand eight hundred and twenty-six,
and in the seventh year of the reign of His Majesty King George the Fourth.
Having steam prepared, and having put the mixture before described into the
retort or cylinder, and screwed down the top or cover, I charge the cistern
with two hundred and fifty pounds of sulphuric acid, not concentrated, but
of a specific gravity from one thousand four hundred to one thousand seven
'hundred and forty; I then introduce part of this acid by means of the pipe
leading from the cistern to the top of the retort or cylinder, and at the same
time, by means of the forcing pump, I force into the bottom of the materials
another portion of the acid, keeping the spindle in motion all the time.
When the materials have been well stirred, so as to be thoroughly mixed, I
admit the steam into the space between the outer and inner sides of the retort or
cylinder, continuing to pump in at intervals the acid till the whole is admitted;
this generally. occupies from four to five hours, when the steam is turned off,
leaving the matter to remain twenty-four hours at least, but generally longer,
as three or four days, some ores requiring more time to oxidize than others,
stirring it two or three times every day; I then charge the cistern with an

page_text: additional quantity of from fifty to seventy-five pounds of sulphuric acid, and
putting on the steam between the two sides and bottom of the retort, I stir the
matter well and pump in the acid as before. In this process the oxide will
appear of a grey or light. brown colour, or a dingy white, according as the
process has been more or less carefully conducted, or as the materials employed
have been of an inferior or superior quality. It remains four or five days in
this state, and to make it into a state fit for use depends on what colour
I intend it for; if for a color which acid and heat do not destroy or spoil, then
the colouring matter is mixed with it in this state: I take a great part or all.
of it out of the retort and mix it with the colouring matter in a vat or tub
lined with lead, and return it into the retort, put on the steam, stirring it at
the same time; by this means the colour becomes so fixed in the oxide that it:
is not liable to change. I use several of the same preparations which colour
makers and dyers use to fix colours. The colours that will not bear heat I
only mix with the oxide in this state of the process and leave them for a few
days. When the colours to be used will not from their nature permit me to
mix them with the oxide while the acid is still with it, I wash it with hot water
till the acid is completely extracted, which may be known by the water being
colourless and tasteless, and its not discolouring substances tinged with vegetable
matter. Having done this, I grind the oxide with the colour and prepare and.
dry them together, in the manner usually done for white lead; I observe the
same method, washing with hot water and after with cold water the oxide.
which has had the colour fixed in the retort. This process is in part the same
as described in the Specification for white lead, but it differs materially.in one
part; the making of white lead requires more materials and cannot be donc
without a certain quantity, whereas this process produces an oxide of lead
which though not white is sufficiently so for the purpose of mixing with
colours, and is equally good and useful for all the purposes. of painting;
preserves its colour, longer without changing, and is by no means so expensive
as white lead. . The quantities of acid and nitre may be varied according to
the colour intended to be.made, putting larger quantities. for lighter colours
and smaller quantities for darker colours, although the same quantities will
not always produce the same shade, owing. to the different quality of the
lead ores.
I think it necessary to make the following observations that every part.
may be clearly understood:-Other sort of retorts may be used provided they
are made so as to allow of the matter being stirred or agitated, and fire may
be used in place of steam. The gas which is disengaged may be either,
suffered to pass off into the open air above: the building where the process is

page_text: carried on, or may be received into a condenser, or burnt, or otherwise disposed
of, but care must be taken not to let any escape from the retort or cylinder
into the place in which you work. When the lead ore is particularly soft
and free from other substances and well burut a smaller quantity of nitre and
sulphuric acid may be used; or if the ore is not good a portion of nitrous acid
may be employed after the first process in the retort instead of sulphuric acid;
it is then dried and proceeded with in the manner before described. I somo-
times also mix the saltpetre with the ore previously and burn them together,
but this requires a larger quantity of saltpetre than by the other method. After
having burnt the mixture I put it into the retort and add the sulphuric acid
to it; or it may be done by burning it with nitre, and also putting it into the
retort with a smaller quantity of nitro. These, however, are only variations of
the same plan. Other acids or compounds of acids or their bases may be also
employed if the ore is hard and mixed with other substances, especially iron.
After having burnt it, ground it fine, and dried it, and reduced it to powder,
I mix it with sulphuric acid for three or four days, or longer, before I mix the
nitre with it in the retort or cylinder.
I will now describe my other improvement in making paint or pigment. It
consists in procuring it from lead-run slag, of which there are different sorts,
according to the manner in which the lead ore has been smelted. For this
purpose the slag must not be too much vitrified, and it must be free from dirt,
if it is not it must be melted over again and run into iron pans or moulds.
The slag must be broke, crushed, ground, washed, and dried. and reduced to
powder, in the manner heretofore stated as to sulphuret of lead, and then put
into the retort. A retort of tho dimensious described in the Patent for whito
lead will not contain half a ton of this matter; it must be mado larger, or
smaller quantities of materials must be used. The cistern is charged with from
two hundred and fifty to five hundred pounds of sulphuric acid, of the gravity
of not less than one thousand two hundred and fifty, not more than one
thousand five hundred; although both the quantity and gravity of the acid
will depend on the nature of the slag, hard and brittle requiring a heavier
acid than the soft slag. I put in part of the acid at the top and pump in the
remainder at the bottom; I keep the steam on two or three hours, and
continue to pump in the acid at intervals. I leave the mixture two or three
days, and if not white enough I add more acid; it is necessary the slag should
be sufficiently moistened with acid to allow of the mixture being turned quietly
and easily by the spindle; this will be a sufficient guide for the quantity to be
used. I then wash it in hot water, as before described for the making of
white lead or oxide of lead, to extract the acid, and again in cold water, and

page_text: grind it and prepare it the same as white lead. I use it for mixing with
various colours and white lead; it gives a hardness and durability to paint,
makes it retain its colour in all weathers and climates; it also makes an
excellent paint by mixing it with several of the substances and matters used
in mixing colours. When the colours to be mixed are not destroyed or injured
by acids, I mix them with it in the rotort after it has been mixed with the
acid, in the manner described for the oxide of lead. When I mix a colour
having a peculiar affinity to any acid, I employ that acid in the place of
sulphuric or the compounds of acids or their bases. For very dark colours
I do not use any acid nor apply any steam, hut grind it up, and wash it and
dry, it and mix it with oil and colours. I do not consider steam absolutely
necessary. The same directions for preparing it with colours, washing it in hot
and cold water, apply to this as to preparing of the oxide of lead.
In witness whereof, I, the said Peter Groves, have hereunto set my hand
and seal, this Eighth day of January, in the year of our Lord One
thousand eight hundred and twenty-seven.