IMPROVEMENTS IN THE MANUFACTURE OF CARBONATE OF SODA
Year: 1859

page_text: LETTERS PATENT to John Wilson, of St. Helen's, in the County of
Lancaster. Manufacturing Chemist, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF CARBONATE OF SODA."
Sealed the 4th November, 1859, and dated the 3rd June 1859.
PROVISIONAL SPECIFICATION
left by
left by the said John Wilson at
the Office of the Commissioners of Patents, with his Petition, on the
3rd June 1859.
I. JOHN WILSON, of St. Helen's, in the County of Lancaster, Manufacturing
Chemist, do hereby declare the nature of the said Invention for "IMPROVE
MENTS IN THE MANUFACTURE OF CARBONATE OF SODA," to be as follows:-
My improvements consist, 1st, in preparing sulphuret of sodium to be
afterwards decomposed by incans of bicarbonate of soda. When sulphate of
soda is mixed with slack or other carbonaceous matter and heated in a
reverberatory furnace, much of the sulphate escapes decomposition, in con-
sequence of the melted sulphate of soda separating on account of its fluidity
from the carbonaceous matter. To prevent this. I add to the sulphate of soda
about one-fourth of its weight of sulphate of barytes. by this means the mixture
is kept in a pasty state, and should any sulphate of soda escape decomposition
in the furnace. this becomes decomposed when water is added to form a
[Price Sd.]

page_text: solution of the sulphuret of sodium, for the sulphuret of barium, which is also
present in the mixture, reacts on the sulphate of soda present, forming
sulphuret of sodium and sulphate of barytes. I also form sulphuret of sodium
by causing sulphate of soda mixed with about one-fifth of its weight of sulphate
of barytes to flow through a column of ignited coke or coal.
2nd, my improvements also consist in the mode of preparing bicarbonate of
soda employed in decomposing the solution of sulphuret of sodium. The
common method of preparing bicarbonate of soda consists in passing carbonic
acid gas into a vessel or chamber containing crystals of carbonate of soda. I
prepare bicarbonate of soda by passing carbonic acid gas over a mixture of
soda ash or carbonate of soda, and crystals of soda, using about one part of
crystals of soda to three parts of soda ash, and for economy, I prefer to use
the impure carbonic acid gas obtained from the combustion of coke.
3rd, my improvements consist also in a mode of condensing the sulphuretted
hydrogen which is disengaged from the sulphuret of sodium when decomposed
by bicarbonate of soda. I cause the sulphuretted hydrogen to pass over
artificial magnetic oxide of iron at the ordinary temperature, in this case
sulphur is precipitated among the oxide of iron, from which it may be burned
off as sulphurous acid gas, and converted into sulphuric acid for the pro-
duction of sulphate of soda.
I claim, first, the addition of sulphate of barytes to sulphate of soda in the
processes for preparing sulphuret of sodium.
Second, the mode of preparing bicarbonate of soda from a mixture of soda
ash and crystals of soda.
Third, the mode of recovering the sulphur from the sulphuretted hydrogen
produced from the sulphuret of sodium, by passing the gas over or through
the artificial magnetic oxide of iron.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by Esther Ryder Wilson, of Saint Helen's, in the County of
Lancaster, Widow. Administratrix of the said John Wilson, deceased.
who departed this life on the Thirty-first day of October, One thousand
cight hundred and fifty-nine, in the Great Seal Patent Office on the
3rd December 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ESTHER
RYDER WILSON, of Saint Helen's, in the County of Lancaster, Widow, Adminis-
tratrix of John Wilson, of the same Place, Chemist, who departed this life on

page_text: the Thirty-first day of October, One thousand eight hundred and fifty-nine,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of June, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second year of
Her reign, did, for Herself. Her heirs and successors, give and grant unto him,
the said John Wilson, Her special license that he, the said John Wilson.
his executors, administrators, and assigns, or such others as he, the said
John Wilson, his 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 make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF CARBONATE OF SODA," upon the condition (amongst
others) that he, the said John Wilson, his executors or administrators, by an
instrument in writing under his, 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
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Esther Ryder Wilson, as such adminis-
tratrix as aforesaid, do hereby declare the nature of the said Invention, and
in what manner the same is to be performed, to be particularly described
in and by the following statement, reference being had to the Drawings
hereunto annexed and to the letters and figures marked thereon (that is to
say):-
'
The said "Improvements in the Manufacture of Carbonate of Soda,"
consist, firstly, in the manufacture of sulphuret of sodium (for the purpose
of converting this into carbonate of soda by the action of carbonic acid
thereon), by decomposing sulphate of soda, either by fluxing such sulphate
in mixture with sulphate of barytes and coke or coal, or by causing such
sulphate in a state of fusion by heat to flow through a column of ignited coke
or coal.
Secondly, in the manufacture of bicarbonate of soda (for the purpose of
using such bicarbonate as a source for carbonic acid, to be applied for affecting
the decomposition of sulphuret of sodium, and consequent production of car-
bonate of soda), by causing a mixture of crystals of carbonate of soda with
dry or nearly dry carbonate of soda to absorb carbonic acid gas.
Thirdly, in the abstraction of sulphur by means of certain oxides of iron

page_text: (herein-after defined) from sulphuretted hydrogen gas, which gas is disengaged
when carbonate of soda is manufactured by the action of carbonic acid on
sulphuret of sodium.
;
In effecting that part of the said improvements by which sulphuret of
sodium is prepared by fluxing sulphate of soda in a furnace in mixture with
sulphate of barytes and coke or coal, it has been found that with careful
working in the furnace, the quantity of sulphate of barytes employed may be
reduced to a small proportion. Thus, by preparing a mixture of four hundred-
weight of sulphate of soda, one-quarter of a hundredweight of sulphate of
barytes, and two and a-half hundredweight of slack (small coal), or two hundred-
weight of coke in coarse powder in place of slack, and causing such mixture to
be fluxed in a reverberatory furnace in the same manner as mixtures of sulphate
of soda with slack and lime are fluxed in the ordinary manufacture of carbonate
of soda, there is obtained sulphuret of sodium, free or nearly free from sulphate
of soda, and suitable for the manufacture of carbonate of soda by decomposing
such sulphuret of sodium by carbonic acid.
In place of using the ordinary reverberatory furnace to effect. such fluxing,
this can be effected still more advantageously (and with a still smaller pro-
portion of sulphate of barytes in the mixture), by means of the rotating
cylinder furnace, for which a Patent was granted to George Elliot and William
Russell, bearing date the Thirteenth day of April, One thousand eight hundred
and fifty-three. In using such rotating furnace, the decomposition of the
mixture is effected without the necessity of introducing tools through openings
into the furnace, and as the access of atmospherical air is thereby prevented,
the gases evolved by the decomposition can be employed to supply carbonic
acid for some of the purposes herein-after mentioned.
In effecting that part of the said improvements by which sulphuret of
sodium is prepared by causing sulphate of soda in a state of fusion to flow
through a column of coke or coal maintained at a bright red heat, it has
been found that such an apparatus as is exhibited in the Drawings hereunto
annexed, is suitable for such purpose.
In these Drawings Fig. 1 is a vertical section of such apparatus; Fig. 2 is
a transverse section taken through the line a, b, of Fig. 1; and Fig. 3 is a
transverse section taken through the line c, d, of Fig. 1; Fig. 4 is a detached
view of one part of the apparatus. In these several Figures the same letters
of reference are used to indicate similar parts of the apparatus.
This apparatus consists of a vessel A, containing a column of coke or coal
(when the latter material is used it is speedily converted into coke, therefore
the column may be regarded as being of coke). This vessel is formed of iron

page_text: plates B lined with fire-bricks C. The column of coke is supported on the
lower part of the vessel B*, which is also coated with fire-bricks C. At a
distance of about two feet from the bottom of the vessel or at E, the space
between the sides of the lining of fire-bricks is diminished to about one half of
the space between the brick lining above and below this position, and this
space is enlarged again gradually, so as to form a hopper of brickwork extending
from the wider part of the vessel to the narrower part at E. A similar
provision is made in the upper part of the vessel at F. These arrangements
will be clearly understood by referring to the Drawings hereunto annexed.
The object of these arrangements is to provide an unobstructed channel or
passage for gases round the column of coke at each of the positions E and F.
At D there is provided an aperture, capable of being closed, communicating
with the interior of the vessel A, through which sulphuret of sodium in a
state of fusion by heat can be run off; G, G, are pipes communicating with
the interior of the vessel A below the part F; these pipes serve for the
admission of air into the channel or passage surrounding the column of coke
below the part F; it is preferred to have eight or twelve or more of these pipes.
Each of them is furnished with a stop-cock for regulating the quantity of air
admitted; H is an opening provided with a door pr stopper J for supplying
coke or coal into the vessel A; K is a flue or passage for the escape of gases
from the vessel O; L is an opening furnished with a cover M for supplying
sulphate of soda into the vessel A. It is preferred to arrange for this cover
being placed in a channel or groove formed after the manner of a lute which
is made good to the iron casing of the vessel A (as shewn in the Drawings)
and to fill this channel or groove with sand. In working with this apparatus
it is desirable that the supply of fused sulphate of soda flowing into the column
of coke should be as nearly uniform as can be conveniently arranged. It has
been found that this can be effected by providing an arch or table of brick-
work N in the upper part of the vessel A, on which supplies of about two
hundredweight at a time of sulphate of soda can be thrown through the
opening L (the cover M being immediately replaced). The arch or table N
has four openings 0, 0, for the passage of heated gases passing up the vessel A
also four openings P, P, for allowing sulphate of soda as it becomes gradually
fluxed on the arch or table N to flow therefrom into the column of coke in the
vessel A.
In place of using the arrangement described with the moveable cover M
for supplying sulphate of soda into the vessel A, a hopper Z (shewn detached
in Fig. 4) may be used for this purpose. This hopper is made of iron and
has a bottom plate Y, through which there are two or more openings. The

page_text: plate Y is covered with a plate X, which has similar openings to those in the
plate Y. A vertical spindle W* is attached to the plate X, and supported
by proper bearings; by means of this spindle the plate X* may be so placed
that its openings correspond with those in the plate Y, when sulphate of soda
contained in the hopper Z will fall through the openings into the vessel A, and
the spindle W being turned so that the solid part of the plate X covers the
openings in the plate Y, the passage of sulphate of soda into the vessel A is
prevented. If the spindle W* be caused to revolve slowly by means of some
mechanical power a regular supply of sulphate of soda can be passed from the
hopper Z into the vessel A, and in this case the arch or table N may be
dispensed with; Q is a furnace for burning coal or coke (the latter being
preferred); it is constructed of a casing of iron plates lined with fire-bricks.
The coal or coke is supported on fire-bars R, and there is an opening at S
furnished with a cover T for introducing coal or coke into the furnace; U is
a flue or passage through which the gaseous products of combustion pass from
the furnace Q to the vessel A into the channel or passage surrounding the
column of coke below the part E, and ascend from thence through such
column of coke. The furnace Q and the vessel A are connected together by
means of iron plates protected by fire-bricks as shewn in the Drawing: V is a
vessel formed of iron plates and filled with silicecus pebbles or other suitable
material. The object of using this vessel (which is connected with the vessel A,
by means of the flue K) is to cool the gases proceeding from the vessel A,
and so render these gases capable of being used to furnish carbonic acid gas;
also to arrest any compounds of soda which may pass over in vapour from the
vessel A; W is a cistern from which water or solution of soda is caused to
How into the vessel V, and such water or solution becoming distributed over the
contents of the vessel V is brought into intimate contact with the gases passing
through the same. The same fluid after having passed through the vessel V
can be elevated into the cistern W, and caused to repass through such vessel
until it may be found to contain such a proportion of compounds of soda as to
make it desirable that its contents should be obtained by evaporation; X is a
centrifugal fan or blowing machine, the inlet passage of which is connected with
the vessel V as shewn in the Drawing, and its outlet passage is connected with
other apparatus, in which the carbonic acid of the gases produced in the
vessel A is utilized. By means of this fan or blowing machine, atmospherical
air is drawn into the furnace Q, causing the combustion of coal or coke
therein, and consequent production of highly heated carbonic oxide, which,
passing through the flue U, enters the vessel A below the part E, and ascends
through the column of coke therein, keeping this at a bright red heat. The

page_text: heated gases are drawn through the orifices in the table N, and pass from the
vessel A by the passage K into the cooling vessel V, and from thence through
the fan or blowing machine X into other apparatus. As the fluxed sulphate
of soda descends through the column of heated coke it becomes decomposed.
producing carbonic acid and carbonic oxide gases, which gases become mingled
with the carbonic oxide gas proceeding from the furnace Q. A supply of
atmospherical air is furnished through the pipes G, G, below the part F of the
vessel A, which causes the combustion of some of the carbonic oxide passing
through the vessel A, and consequent production of an increased proportion of
carbonic acid in the gases; also causes an increase of heat in the upper
part of the vessel A. This supply of air is regulated by the stop-cocks, taking
care that the quantity admitted shall not be sufficient to allow free oxygen to
be present in the gases passing from the vessel A; a supply of coke in small
pieces is furnished into the vessel A, so as to keep the column of coke
therein. The quantity of sulphate of soda which may be decomposed by this
apparatus will depend upon the area and the depth of the column of coke
contained therein, and the supply of sulphate of soda should be regulated
accordingly. The sulphur of sodium produced becomes collected in a fluid
state at the lower part of the vessel A, and should be withdrawn from time to
time by opening the aperture D. This sulphuret should be received in iron
vessels, and be immediately covered over with pounded coke. to prevent
oxydation by access of atmospherical air.
The manufacture of sulphuret of sodium by the decomposition of sulphate
of soda by means of carbon has heretofore been effected by fluxing sulphate of
soda in mixture with slack or with ground coke in reverberatory furnaces.
This manufacture has been described in the Specifications of sundry Patents
obtained for Inventions connected with the manufacture of soda. In some of
these Specifications directions are given for the use of defined quantities of
sulphate of soda and carbonaceous matter; in others the sulphate of soda is
directed to be kept in a state of fusion in contact with a large quantity of coke
in small pieces, the quantity of coke employed being much more than sufficient
to effect the decomposition of the sulphate of soda. if the contact be sufficiently
prolonged. By either of these means sulphuret of sodium may be obtained,
retaining more or less of sulphate of soda, whilst by means of the improve-
ments herein-before described sulphuret of sodium is obtained either free or
practically free from sulphate of soda.
In effecting that part of the said improvements which comprises the pre-
paration of bicarbonate of soda, for the purpose of applying the carbonic acid
of such bicarbonate of soda to the decomposition of sulphuret of sodium, for

page_text: the production of carbonate of soda, a mixture is prepared consisting of
crystals of carbonate of soda, with dry or nearly dry carbonate of soda, in the
proportion of one part of the former to about three parts of the latter, and
such mixture is placed in thin layers on shelves or trays contained in a closed
chamber, (such as is used in the ordinary manufacture of bicarbonate of soda
from crystals of soda alone), and a supply of carbonic acid gas is conducted
into such chamber. Such supply of carbonic acid gas may be obtained by the
calcination in a kiln of limestone or chalk in mixture with coke, or by the
decomposition of sulphate of soda, as herein-before explained, or by other
means; and, after having caused the gases so produced to become cooled, to
conduct such cooled gas into the chamber containing the mixture of crystallized
and dry or nearly dry carbonate of soda, when carbonic acid becomes absorbed
by such mixture. The supply of carbonic acid gas is continued until it is
found by trial that the whole or the greater part of the carbonate of soda con-
tained in such chamber has become converted into bicarbonate of soda, and
has therefore become suitable to yield carbonic acid for decomposing sulphuret
of sodium, and producing carbonate of soda.
In effecting the decomposition of sulphuret of sodium by means of carbonic
acid contained in bicarbonate of soda (obtained, as herein-before described),
such carbonic acid may be applied directly or without being disengaged in a
gaseous state from the bicarbonate of soda, or indirectly by being liberated in
a gaseous state from such bicarbonate of soda, and then applied to effect such
decomposition. When the decomposition of sulphuret of sodium is effected by
the direct application of carbonic acid contained in bicarbonate of soda
(prepared as herein-before described), a solution is obtained by lixiviating
sulphuret of sodium with water in the same manner as black ash is ordinarily
lixiviated, or by adding sulphuret of sodium to water, and causing this to be
heated. This solution (after the deposition of undissolved matter ceases) is trans-
ferred to an iron vessel or boiler capable of being closed, and arranged so that its
contents may be heated either by the application of fire or by the injection of
steam, and having a pipe for conveying gas therefrom to other apparatus.
Bicarbonate of soda (prepared, as herein-before described) is now added to
the contents of such vessel through an aperture provided for that purpose,
which is immediately closed. (The suitable proportions of the solution of
sulphuret of sodium and of bicarbonate of soda to be used should be ascertained
by a preliminary trial, these being such as will yield a solution of carbonate
of soda free or nearly free from sulphuret of sodium.)
to the mixture, and as carbonic acid of bicarbonate
Heat is now applied
becomes transferred
to the base of the sulphuret of sodium, sulphuretted hydrogen gas is liberated,

page_text: and is conducted from the vessel employed to other apparatus, in which it is
treated for the abstraction of sulphur therefrom by the means which will be
herein-after particularly described.
The application of heat to the mixture is contained until the whole or nearly
the whole of the sulphur previously contained in such mixture has been
expelled therefrom. The residual liquor now contains but little saline matter,
except carbonate of soda, and by treating this liquor in the manner similar to
that usually adopted with ordinary liquors containing carbonate of soda, this
substance in the state of crystals or of dryness can be obtained therefrom.
When the decomposition of sulphuret of sodium is effected by the action
thereon of carbonic acid in a gaseous state, obtained from bicarbonate of soda
(prepared as herein-before described), it is preferred to introduce such bicar-
bonate of soda into iron retorts (similar to the iron retorts used in the
manufacture of coal gas), and to apply heat thereto, which causes the expulsion
of carbonic acid gas therefrom, which gas is conducted from such retorts into
other apparatus containing sulphuret of sodium, in which such decomposition
is effected, in the manner herein-after particularly explained, when describing
the decomposition of sulphuret of sodium by means of carbonic acid gas
obtained by other means.
For the purpose of effecting that part of the said improvements which
comprises the abstraction of sulphur from sulphuretted hydrogen gas dis-
engaged when carbonate of soda is manufactured by the action of carbonic acid
gas on sulphurct of sodium, carbonic acid gas obtained from other sources
than bicarbonate of soda is available. Thus, the pure carbonic acid gas which
is extricated from earthy carbonates by the action thereon of muriatic acid or
other acids is suitable for such purpose. Also, the impure carbonic acid gas
which is evolved when limestone or chalk is calcined with coke (proper care
being taken to prevent the presence of free oxygen in such gas).
An appa-
ratus well suited for obtaining carbonic acid gas by these means, is described
in the Specification of an Invention for which Letters Patent were granted to
William Gossage, bearing date the Ninth day of November, One thousand eight
hundred and fifty-two. Also, the impure carbonic acid gas which is liberated
during the decomposition of sulphate of soda by means of carbon.
Carbonic acid gas may be applied to the decomposition of sulphuret of
sodium, and consequent production of carbonate of soda when sulphuret of
sodium is in the state of solution with water. In this case the solution of
sulphuret of sodium should be caused to descend through a closed tower neariv
filled with small pieces of coke (over which the solution should be distributed
as evenly as may be practicable), at the same time that supply of carbonic

page_text: acid gas is caused to ascend through the interstices existing between the
picces of coke contained in such tower. By these means the solution passing
through the tower is caused to absorb carbonic acid, thereby producing
carbonate of soda, and sulphuretted hydrogen gas is liberated and conducted to
other apparatus in which sulphur is abstracted from such sulphuretted hydrogen
by the agency of oxide of iron. The liberation of sulphuretted hydrogen gas
in this mode of producing carbonate of soda is facilitated by introducing a
supply of steam together with carbonic acid into the tower.
Carbonic acid gas may be applied to the decomposition of sulphuret of
sodium and consequent production of carbonate of soda when such sulphuret
of sodium retains the solid form.. In this case it is preferred to use a set of
vats such as are used for the lixiviation of black ash in the ordinary manu-
facture of carbonate of soda, such vats being furnished with covers and pipes
for the conveyance of gases to and from each other, and to and from other
apparatus (an apparatus by which carbonic acid gas can be applied to effect.
the decomposition of sulphuret of sodium when in a solid staic, is described in
the said Specification of a Patent granted to William Gossage. bearing date
the Ninth day of November. One thousand eight hundred and fifty-two.)
In using such apparatus, the vats are charged with lumps of sulphuret of
sodium, and if such lumps do not contain sufficient unconsumed coke to give
suitable porosity to the sulphuret of sodium when this becomes slaked to
powder, a sufficient quantity of pieces of coke is mingled with such lumps.
A supply of steam is now introduced under the false bottom of each vat so
charged, and this is continued until the lumps of sulphuret of sodium have
become slaked to powder. A supply of carbonic acid gas, together with steam
is now introduced into the vats, and caused to pass through a series of these
consecutively. By these means carbonic acid becomes absorbed by the base
of the sulphuret of sodium, producing carbonate of soda, and sulphuretted
hydrogen gas is liberated, which gas is conducted from the decomposing appa-
ratus into other apparatus wherein sulphur is abstracted from such gas by
the use of oxide of iron. The application of carbonic acid gas to the sulphuret
of sodium is continued until it is found that the whole or nearly the whole of
the sulphur previously contained in such sulphuret of sodium has been
expelled. The residual matter is then lixiviated with water and solution of
carbonate of soda thereby produced, from which may be obtained carbonate
of soda in a marketable form.
In effecting that part of the said improvements by which sulphur is
abstracted by means of oxide of iron from the sulphuretted hydrogen gas,
which is disengaged when carbonate of soda is manufactured by the decom-

page_text: position of sulphuret of sodium by means of carbonic acid, it has been found
that such abstraction may be conveniently effected by the use of an apparatus
consisting of a series of chambers built of bricks in Roman cement, and
provided with a number of perforated floors, on which the oxide of iron
employed is placed. The gases proceeding from the apparatus in which the
decomposition of sulphuret of sodium is being effected, are conducted to one of
these chambers, and caused to percolate through the layers of oxide of iron
placed on the perforated floors therein, and conducted from thence to other
chambers also containing oxide of iron on perforated floors, these chambers
being arranged so that gases can be passed through them consecutively, and
be thereby caused to filter through a large quantity of oxide of iron; the first
chambers into which the gases are introduced containing oxide of iron which
has been previously treated with sulphuretted hydrogen, and the last chambers
containing fresh oxide. By these means the oxide of iron becomes highly
charged with sulphur, and the last portions of sulphur can be abstracted from
the gases.
In place of using chambers for this purpose it has also been found
that a tower built of brickwork may be conveniently used when the oxide of
iron employed is in lumps. The tower may be about six feet square and
twenty feet high, and should be provided with a grating at its lower part for
supporting the lumps of oxide of iron with which the tower is filled, and
through which the sulphurized oxide may be withdrawn. Gases containing sul-
phuretted hydrogen proceeding from the decomposition of sulphurct of sodium
should be introduced into the tower below its grating, and such gases ascending
in the tower filter through the oxide of iron contained therein, and sulphur is
abstracted from such gases, the required movements of the gases can be readily
effected by the use of blowing fans or air pumps. As the abstraction of
sulphur from sulphuretted hydrogen gas progresses with the same oxide of
iron, this oxide becomes loaded with sulphur and gradually loses its power of
abstracting sulphur. Such capability of abstracting sulphur may be restored
by causing atmospherical air to come in contact with the partially sulphurized
oxide. Thus it has been found suitable to cause sulphuretted hydrogen to
pass through the oxide during a period of time, and then to shut off the
supply of sulphuretted hydrogen from the chambers or tower, and admit
atmospherical air therein during another period of time. By means of these
alternate applications of sulphuretted hydrogen and of atmospherical air, the
oxide may be loaded with sulphur until its capability of abstracting a further
quantity of sulphur from sulphuretted hydrogen gas becomes feeble; such
sulphurized oxide is then withdrawn from the apparatus, and sulphur is set
free from it either by distillation from earthen retorts when it is obtained as

page_text: The
solid sulphur, or by combustion with atmospherical air when it is obtained as
sulphurous acid gas applicable for the manufacture of sulphuric acid.
oxide of iron remaining after such separation of sulphur by distillation or
combustion is well suited to be applied again for the abstraction of sulphur
from sulphuretted hydrogen gas. The oxides of iron which are suitable to
effect the objects of the said Invention of John Wilson (so far as the same
applies to the abstraction of sulphur from sulphuretted hydrogen gas, as herein-
before explained,) are all such artificial oxides of iron as are in any degree.
magnetic. Amongst these may be enumerated the artificial oxide of iron which
is produced largely in the ordinary manufacture of carbonate of soda, being
obtained by burning off sulphur from iron pyrites.
This oxide is well adapted for effecting this part of the said Invention when
parties may commence the manufacture of carbonate of soda by means of
these improvements, also for supplying any waste of oxide of iron which may
occur during the workings.
The oxide of iron which will be obtained most economically, and which is
well suited for effecting this part of the said Invention, is the artificial magnetic
oxide of iron remaining after driving off sulphur from any oxide of iron
which has has been previously used for abstracting sulphur from sulphuretted
hydrogen gas.
There are certain ores or native oxides of iron (some of which are magnetic).
and which may be used for the abstraction of sulphur from sulphurcited
hydrogen gas, such abstraction being effected at an elevated temperature.
After these ores have been thus sulphurized, and sulphur has been driven
therefrom, they become converted into artificial magnetic oxides, well suited
for effecting that part of the said Invention which applies to the abstraction
of sulphur from sulphuretted hydrogen gas at ordinary temperatures.
When it is found desirable to use such native oxides, it is preferred to
subject these to a process of cementation with carbon, in the manner described
in the Specification of a Patent, granted to Thomas Spencer, bearing date the
Twenty-ninth day of December, One thousand eight hundred and fifty-seven,
for purification of illuminating gas, or in some other suitable manner, such
native oxides are thereby converted into artificial magnetic oxides, well suited
for the abstraction of sulphur from sulphuretted hydrogen gas at ordinary
temperatures.
The said native oxides may also be rendered suitable for such purpose by
mingling therewith a portion of highly magnetic oxide obtained by such
process of cementation.
An artificial magnetic oxide of iron, well suited for the abstraction of

page_text: sulphur from sulphuretted hydrogen gas, may also be obtained by calcining
native carbonates of iron, without these ores requiring to be cemented with
carbon.
In the foregoing particulars there are described certain apparatus which
have been found suitable for effecting the Invention of my deceased husband,
John Wilson, also certain proportions of materials which it has been found
suitable to employ in effecting such Invention, but it is not intended to claim
any exclusive right to the use of such apparatus, or to the use of such materials
in the proportions particularized, or to be restricted from the use of other
apparatus, or from the use of such materials in other proportions in effecting
the said Invention.
.
..
I claim as the Invention for which the herein-before in part recited Letters
Patent were, granted to my deceased husband, John Wilson, for his Invention
of improvements in the manufacture of carbonate of soda,-
Firstly, the manufacture of sulphuret of sodium (for the purpose of con-
verting this into carbonate of soda by the action of carbonic acid thereon) by
decomposing sulphate of soda, either by fluxing such sulphate in mixture with
sulphate of barytes and coke or coal, or by causing such sulphate, in a state of
fusion by heat, to flow through a column of coke or coal at a bright red
heat.
Secondly, the manufacture of bicarbonate of soda (for the purpose of using
such bicarbonate of soda as a source for carbonic acid to be applied for
effecting the decomposition of sulphuret of sodium) by causing a mixture of
crystals of carbonate of soda with dry or nearly dry carbonate of soda to absorb
carbonic acid gas.
1
Thirdly, the abstraction of sulphur by the use of such artificial oxides of
iron as are in any degree magnetic from sulphuretted hydrogen gas, which gas
is disengaged when carbonate of soda is manufactured by the action of
carbonic acid on sulphuret of sodium.
•
In witness whereof, I, the said Esther Ryder Wilson, as such adminis-
tratrix as aforesaid, have hereunto set my hand and seal, this Second
day of December, in the year of our Lord One thousand eight hundred
and fifty-nine.
5 Witness,
JNO. K. LEATHER,
of St. Helen's.
ESTHER RYDER WILSON. (L.S.)