IMPROVEMENTS IN TREATING THE OXIDES OF IRON, AND IN OBTAINING PRODUCTS THEREFROM
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
LONGMAID, of Beaumont Square, in the County of Middlesex, Gentleman, 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 Twenty-sixth day of
October, One thousand eight hundred and forty-eight, in the twelfth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Longmaid, my exors, admors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said William Longmaid, my
exors, admors, and assigns, or such others as I, the said William Longmaid,
my exors, adñors, 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, and also in the Islands of Jersey,
Guernsey, Alderney, Sark, and Man, and in all Her said Majesty's Colonies
and Plantations abroad, my Invention of "IMPROVEMENTS IN TREATING THE
OXIDES OF IRON, AND IN OBTAINING PRODUCTS THEREFROM;" in which said Letters
Patent is contained a proviso that I, the said William Longmaid, should cause
a particular description of the nature of my said Invention, and in what
manner the same is to be performed, by an instrument in writing under
my hand and seal, to be inrolled in Her said Majesty's High Court of
Chancery within six calendar months next and immediately after the date

page_text: 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
William Longmaid, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are particularly described
and ascertained in and by this present Specification or Instrument in writing,
as follows (that is to say):-
My said Invention consists of a mode or modes of treating oxides of iron
by mixing them with carbonaceous matter, and then subjecting the compound
to the action of heat, whereby I am enabled to obtain certain products there-
from, and the products which I am thus enabled to obtain are a black or dark
colored pigment, or volatile oleaginous product, and an inflamable gas.
For this purpose I take oxide of iron, either native or artificial, and the more
pure the better, and pulverize it finely, and then mix it intimately with some
carbonaceous matter. The proportions of these ingredients so to be mixed
may be varied very considerably; the addition of about ten per cent. of carbon
to the oxide would generally be sufficient to produce the desired effect, but I
deem it more advantageous to use a little excess of carbonaceous matter to
ensure the success of the process, and therefore I prefer to mix the oxide of
iron with from twelve to fifteen per cent. by weight of the carbonaceous
matter, or such a quantity of it that when the process is complete a slight
excess of the carbonaceous matter will remain in the retort.
Any description
of carbonaceous matters which are not too volatile or expensive, and which
can be mixed intimately with the oxide of iron, may be used, but when not in
a fluid state they must be pulverized; those which I have found most con-
venient and advantageous for the purposes of my Invention are tar and resin.
When I use resin, I first pulverize it, and then mix it intimately with the
oxide of iron in a dry state. When I use tar I mix it with the oxide of iron
in a moist state for the purpose of facilitating the thorough incorporation of
the materials with each other, and then dry the mixture at a temperature
sufficient to deprive it of nearly the whole
state of powder in any ordinary manner.
materials to be used in the way I have
close vessel or chamber, in which it can be heated to a low red heat without
being subject to the action of any atmospheric air, and I prefer for this
purpose cast-iron retorts of the ordinary description, made five feet long and
one foot in diameter, with a cover to be fastened upon the open end in the
ordinary manner, and a ring at the opposite end for the purpose of lifting it.
I have found retorts of this size to be convenient, but they may of course be
of its moisture, and reduce it to a
Having prepared the mixture of
described, I put it into a retort or

page_text: varied in shape, size, and material. A retort of the size I have mentioned
may be conveniently charged with about one and a half hundredweight of the
mixture, after which (the cover being secured) it is to be lifted by a crane or
other convenient means, and placed in a furnace with a fire beneath the place
upon which it is placed (as in using retorts), such as just mentioned. I burn
the volatile products evolved by the heat. I place the retorts in the furnace
in a vertical position with the cover end downwards, so that the combustion
of the volatile products may assist in heating the retorts. The heat is to be
raised gradually, until the whole of each retort becomes uniformly of a low
red heat, at which temperature it must be kept until about two hours after the
combustible volatile products have ceased to be evolved. The process being
now complete, I remove the retort from the furnace, and I suffer it to become
cold, or nearly so, before the charge is withdrawn, as it would be injured by
contact with the air whilst hot. The material produced by calcination in a
retort in this way will be found to be black or dark colored, and forms a good
pigment for many purposes.
Some carbonaceous matters, when used in the
production of this material, will cause it to be sufficiently pulverulent, but
when this is not so it must be ground before it is mixed with oil, after which
it is to be mixed and ground with oil, so as to form paint in the usual way.
When I do not intend to burn the combustible volatile products of the cal-
cination, I lute the cover on to the retort in the usual way, so as to make it
air-tight, or nearly so, and insert a pipe so as to convey the volatile products
evolved by the calcination to any convenient vessel or vessels. The calcination
will cause a volatile oil to be evolved from the contents of the retort, which I
convey by the pipe just mentioned to a condenser or other convenient vessel
in which it may be condensed and retained. The calcination will also cause
the evolution of an inflammable gas suitable for the purposes of illumination,
which I convey by a pipe from the condenser or vessel first mentioned to a
gasometer of any ordinary construction.
And having now described the nature of my said Invention, and the manner
in which it is to be performed, I hereby declare that I claim as of my said
Invention the mode or modes of treating oxides of iron by mixing them with
carbonaceous matters, and subjecting them to the action of heat, in manner
herein-before described, for the purpose of obtaining one or more of the several
products herein-before mentioned.
In witness whereof, I, the said William Longmaid, have hereunto set
my hand and seal, this Twenty-sixth day of April, in the year of our
Lord One thousand eight hundred and forty-nine.
WILLIAM (L.S.) LONGMAID.

page_text: AND BE IT REMEMBERED, that on the Twenty-sixth day of April, in
the year of our Lord 1849, the aforesaid William Longmaid came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose.
Enrolled the Twenty-sixth day of April, in the year of our Lord One
thousand eight hundred and forty-nine.