A NEW PROCESS OF MANUFACTURING CARBONATE OF SODA BY THE APPLICATION OF SULPHURET OF SODIUM, AND IN APPARATUS
Year: 1862

page_text: LETTERS PATENT to Louis Désiré Verstraet, Chemist and Etienne
Maurice Olivier, Proprietor, both of 29, Boulevart St. Martin, Paris,
for the Invention of "A NEW PROCESS OF MANUFACTURING CARBONATE OF
SODA BY THE APPLICATION OF SULPHURET OF SODIUM, AND IN APPARATUS
PAR
Sealed the 3rd February 1863, and dated the 13th August 1862.
PROVISIONAL SPECIFICATION left by the said Louis 1.ésiré Verstraet and
Etienne Maurice Olivier at the Office of the Commissioners of
Patents, with their Petition, on the 13th August 1862.
We, Louis DESIRE VERSTRAET, Chemist, and ETIENNE MAURICE
OLIVIER, Proprietor, both of 29, Boulevart St. Martin, Paris, do hereby
declare the nature of the said Invention for "A NEW PROCESS OF MANU-
FACTURING CARBONATE OF SODA BY THE APPLICATION OF SULPHURET OF SODIUM.
AND IN APPARATUS FOR THE SAME," to be as follows:-
Our Invention relates to the manufacture of carbonate of soda by the
aid of sulphuret of sodium. We are aware that many attempts have
been made with this object in view, but which have furnished too unsatis-
factory results for manufacturing on a large scale, while these processes
have further almost always produced hyposulphite of soda instead of
carbonate of soda.

page_text: This improved process of our Invention offers great advantages in the
manufacture of artificial soda, and enables the retention of nearly the
whole of the suphuric acid which is wasted in the ordinary processes.
Sulphuret of sodium alone in the presence of an excess of carbonic acid
only produces a very small portion of bi-carbonate of soda, but on the
contrary creates a large quantity of hyposulphite of soda.
In order that the sodium of the sulphate may combine with the carbonic
acid injected in the solution, it requires to be in the presence of an
oxidated agent capable of absorbing hydrosulphuric acid immediately
it forms, that is to say, in a nascent state, and abandoning in its turn
its oxygen to the sodium. The latter passing then into a state of soda,
combines with the greatest facility with the carbonic acid, in order to
constitute a solution of bi-carbonate of soda. By calcining it in a
reverberatory furnace, the latter salt is transformed into neuter carbonate
of soda; lime is the agent employed in the oxidation of the soda. Milk
of lime when introduced into the solution of monosulphuret of sodium
absorbs the hydrosulphuric acid, or rather the sulphur of the sulphuret of
sodium, in order to form (the same as in the manufacture of artificial
soda) oxysulphuret of calcium. The following is the reaction that takes
place-
2NaS+3CaO+400=2NaO, (CO) + CaO, 2 (Cas).
This reaction is however separated almost immediately on its formation,
and the excess of carbonic acid necessary for the production of
bi-carbonate of soda acting in its turn (on the production of the latter)
upon the oxysulphuret of calcium, which is formed, transforms it into
carbonate of lime by setting the hydrosulphuric acid at liberty.
CaO, 2 (CaS) + 3CO³ + 2HO=30O, CO* + 2HS.
By the combustion of the hydrosulphuric acid in a space filled with
oxygen, that is to say, in a large volume of air it becomes transformed
into sulphuric acid, which is introduced into leaden chambers, or by the
ordinary processes the sulphurous acid is transformed into sulphuric
acid. In order to effect the combustion of the hydrosulphuric acid we
simply convey it into furnaces for the combustion of iron pyrites, which
are now almost exclusively used for the manufacture of sulphuric acid.
Carbonic acid is produced by the combustion of a mixture of coke and
charcoal in a cast-iron receiver, or in a blowing machine which is
furnished with a continual supply of air, as employed in sugar refineries
on the principle of saturation, and which being well known will require
no further description.
Our improved process thus consists in placing a solution of sulphuret

page_text: of sodium in contact with milk of lime, and a current of carbonic acid.
While the carbonic acid is being disengaged, an agitator furnished with
pallets keeps the matters constantly stirred, in order to prevent the
deposit of the lime and the oxysulphuret of calcium formed, and so as to
bring the current of carbonic acid in as complete contact as possible
with the solution. A worm tube supplied with steam heats the liquids
in order to hasten the reaction, and so as to disengage the gaseous hydro-
sulpuric acid as easily as possible immediately it forms by preventing it
from dissolving in the soda solution.
DESCRIPTION OF THE APPARATUS.
Our improved process is effected in the most simple manner. We
effect in the same furnace, seen in Fig. 1 of the annexed Drawing, both
the transformation of the marine salt into sulphate of sodium, and also
that of the sulphate of soda into sulphuret of sodium. The furnace is
so constructed that the flame from the fire shall give up the greatest
possible quantity of caloric, for which purpose it is caused to traverse in
the direction indicated by the arrows. In the leaden boiler D, which
is supported by plates of iron, is placed a mixture of marine salt and
sulphuric acid, the vapours of the hydrochloric acid pass off by the earthen
tube D' in order to be condensed in apparatus not shown in the Drawing..
From the leaden boiler D the sulphate of soda which forms passes into
the part C of the furnace, where its calcination is effected, after which
the sulphate is caused to pass over the sole B next the fire, where it is
mixed with the charcoal necessary for transforming it into sulphuret;
there is also added from 3 to 4 per cent. of carbonate of lime, in order
to prevent as much as possible the formation of polysulphurets. The
sulphuret, when once formed, is withdrawn from the furnace, the sub-
sequent operations follow the same course as the vapours which disengage
from the sole C of the furnace where the calcination of the sulphate is
effected still contain hydrochloric acid. they pass through the earthen
tube E' into condensing apparatus, where they are deprived of their
acidity, and thence pass into the chimney. The sulphuret, when with-
drawn from the furnace, is thrown into the boiler A, Fig. 2, where it is
washed, a worm tube, heated by steam, heats the water to a temperature
of from 104 to 113 degrees Fahrenheit, in order to dissolve the whole of
the soluble parts. When the solution is complete the liquors are allowed
to rest in order to settle, they then pass through cock B into a closed filter
C, Fig. 5, consisting of a sheet-iron sieve pierced with holes and con-
taining fine grit mixed with charcoal, intended for retaining the
impurities of the sulphuret. On passing out at the bottom of the filter

page_text: the clear liquors pass through cock d into a stone cistern G, whence the
sulphuret in solution is raised by means of a pump into the cistern F,
which effects the distribution of the liquors in the decomposing apparatus
H, H¹, H², Fig. 3, by means of a cock a. In commencing this operation
we first introduce the milk of lime into the first apparatus H by means
of a funnel cock I and then add the sulphuret of sodium in solution.
During the introduction of these matters the small air cock i is opened
in order to prevent the formation of a vacuum. When the matters have
been introduced into boiler A a current of carbonic acid is forthwith
supplied to it from the coke-burning apparatus, which is not represented
in the Drawing. The current of carbonic acid arrives by tube M and
is introduced in apparatus H by tube N, which serves at the same time
as an axis for the agitator o. This agitator is set in motion by means
of gearing X, and is in motion during the whole time that the jet of
carbonic acid is being supplied, which thus prevents the deposit of the
lime and oxysulphuret of calcium. We then ascertain whether the
liquor is changed to a state of bi-carbonate of soda by withdrawing a
little of it from the boiler H by means of cock y. The salt is then filtered,
calcined, and tested, either with normal sulphuric acid or with a solution
of nitrate of silver, which should indicate in the salt obtained but slight
traces of hyposulphite of soda. During the operation the hydrosulphuric
acid which disengages, as also the excess of carbonic acid, passes into the
second apparatus H', which is similar to apparatus H, by means of a
tube and cock J. This second apparatus also contains a solution of
sulphuret of sodium, intended to absorb any excess of carbonic acid which
may be disengaged in apparatus H. The hydro-sulphuric acid passes
off by means of cock K from apparatus H', and passing thence through
tube L, which is common to the whole series of apparatus, is conducted
into the furnaces for treating pyrites, the position of which is indicated
by the letter Z, where it is transformed into sulphurous acid. This acid
is then transformed into sulphuric acid in leaden chambers, represented
in the Drawing by letter Z¹. When the operation is terminated in
apparatus II a current of carbonic acid is passed into apparatus H',
which, in its turn, communicates with apparatus H³, where the operation
is continued as before described. As the solution of bi-carbonate con-
tained in the boiler H may still retain a little hydrosulphuric acid in
solution we deprive it of the latter by boiling the solution by means of a
worm e heated with steam. The small cock b is opened, which introduces
steam into the worm from a generator supplied by means of a general
pipe P; the water of condensation passes out through cock g and pipe h.

page_text: The vapours of the hydrosulphuric acid and the water pass through the
cock K" into a general pipe L, which conducts them to the furnace con-
taining the pyrites. Before opening the cock K" the cock J is closed,
which communicates with the apparatus H¹. When the solution of bi-
carbonate of soda has boiled for a few minutes the steam cock is closed,
as also the cock K". The liquors are allowed to rest in order that the
carbonate of lime may settle at the bottom of the boiler, and when the
liquors are quite clear they are drawn off by cock Q. The clear liquor
is then conveyed, by means of wood channels, into the cast-iron boiler E
placed over the furnace, Fig. 1, and after they have been well concen-
trated in said boiler they may be treated in two different manners. Thus
they may be directly calcined in a reverberatory furnace in order to
obtain carbonate of soda, or they may be introduced into sheet-iron
boilers, in which the salt may be extracted by precipitation. The mother-
waters resulting from the latter process may afterwards be crystallized.
The thick liquors remaining in apparatus H are conveyed by means of
cock R into wood channel S, whence they pass into the boiler, Fig. 4.
In this boiler said matters are washed with boiling water, and these
weak waters, charged with a little bi-carbonate of soda, serve instead
of pure water for dissolving, in boiler A, Fig. 2, the sulphuret of sodium
on its exit from the furnace. When the deposit of carbonate of lime has
been sufficiently washed the exhausted matters are conveyed away by
means of cock Y through channel l. These matters consist of carbonate
of lime in a nearly pure state. They may then be utilized for the pro-
duction of the lime necessary for decomposing the sulphuret, so that the
same lime may serve for an almost indefinite length of time. We may
also, in order to economize the production of carbonic acid, collect the
said acid which is disengaged by the calcination of the carbonate of lime
in a gasometer, and so employ it for the decomposition of the sulphuret
of sodium. On leaving the boiler, Fig. 4, the carbonate of lime is of
a dull green color, which, after being exposed a day or two to the air,
becomes completely white. The apparatus may be made of any desired
dimensions, according to the purpose of the manufacturer.
The chief features of our Invention are, 1st, the formation of carbonate
of soda by transforming sulphuret of sodium into bi-carbonate of soda.
whatever may be the manner in which the sulphuret of sodium is obtained
2ndly, the employment of lime or other oxidated agents capable of
answering similar purposes.
And, 3rdly, the arrangement of furnace and other apparatus repre-
sented in the annexed Drawing.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Louis Désiré Verstraet and Etienne Maurice Olivier in
the Great Seal Patent Office on the 13th February 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME. we, 1.OUIS
DESIRE VERSTRAET, Chemist, and ETIENNE MAURICE OLIVIER, Proprietor,
both of 29, Boulevart St. Martin, Paris, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of August, in the year of our
Lord One thousand eight hundred and sixty-two, in the twenty-sixth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto us, the said Louis Désiré Verstraet, and Etienne Maurice
Olivier, Her special licence that we, the said Louis Désiré Verstraet and
Etienne Maurice Olivier, our executors, administrators, and assigns, or
such others as we, the said Louis Désiré Verstraet and Etienne Maurice
Olivier, our 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
"A NEW PROCESS OF MANUFACTURING CARBONATE OF SCDA BY THE APPLICATION
OF SULPHURET OF SODIUM, AND IN APPARATUS FOR THE SAME," upon the con-
dition (amongst others) that we, the said Louis Désiré Verstraet and
Etienne Maurice Olivier, our executors or administrators, by an instru-
ment in writing under our, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, 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 we, the said Louis Désiré Verstraet and Etience
Maurice Olivier, our, do hereby declare the nature of our said Invention,
and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, reference
being had to the Sheet of Drawings hereunto annexed, and to the letters
and figures marked thereon (that is to say), -
Our Invention relates to the manufacture of carbonate of soda by the
aid of sulphuret of sodium. We are aware that many attempts have
been made with this object in view, but which have furnished too unsatis-
factory results for manufacturing on a large scale, while these processes
have further almost always produced hyposulphite of soda instead of
carbonate of soda.

page_text: The improved process of our Invention offers great advantages in the
manufacture of artificial soda, and enables the retention of nearly the
whole of the sulphuric acid which is wasted in the ordinary processes.
Sulphuret of sodium alone, in the presence of an excess of carbonic acid,
only produces a very small portion of bi-carbonate of soda, but, on the
contrary, creates a large quantity of hyposulphite of soda.
In order that the sodium of the sulphuret may combine with the
carbonic acid injected in the solution, it requires to be in the presence of
an oxidated agent capable of absorbing hydrosulphuric acid immediately
it forms, that is to say, in a nascent state, and abandoning in its turn its
oxygen to the sodium; the latter passing then into a state of soda,
combines with the greatest facility with the carbonic acid in order to
constitute a solution of bi-carbonate of soda. By calcining it in a
reverberatory furnace, the latter salt is transformed into neuter carbonate
of soda. Lime is the agent employed in the oxidation of the soda. Milk
of lime, when introduced into the solution of monosulphuret of sodium,
absorbs the hydrosulphuric acid, or rather the sulphur of the sulphuret
of sodium, in order to form (the same as in the manufacture of artificial
soda) oxysulphuret of calcium. The following is the reaction that takes
place:-
2 NaS+3CaO + 400 = "NaC, (CO² + CaO, 2 (CaS).
The reaction is, however, separated almost immediately on its formation,
and the excess of carbonic acid necessary for the production of bi-
carbonate of soda, acting in its turn on the production of the latter upon
the oxysulphuret of calcium which is formed, transforms it into carbonate
of lime by setting the hydrosulphuric acid at liberty.
CaO, (Cas)+ 3CO + H()=3CaO, CO² + 2HS.
By the combustion of the hydrosulphuric acid in a space filled with
oxygen, that is to say, in a large volume of air, it becomes transformed
into sulphurous acid, which is introduced into leaden chambers, or by the
ordinary processes the sulphurous acid is transformed into sulphuric
acid. In order to effect the combustion of the hydrosulphuric acid, we
simply place it in furnaces for the combustion of. iron pyrites, which are
now almost exclusively used for the manufacture of sulphuric acid.
Carbonic acid is produced by the combustion of a mixture of coke and
charcoal in a cast-iron receiver or in a blowing machine, which is
furnished with a continual supply of air, as employed in sugar refineries
on the principle of saturation, and which being well known, will require
no further description. Our improved process thus consists in placing a
solution of sulphuret of sodium in contact with milk of lime and a current

page_text: of carbonic acid. While the carbonic acid is being disengaged, a spatula
furnished with pallets keeps the matters constantly stirred in order to
prevent the deposit of the lime and the oxysulphuret of calcium formed,
and so as to bring the current of carbonic acid in as complete a contact
as possible with the solution. A worm tube of steam heats the liquids
in order to hasten the reactions, and so as to disengage the gaseous hydro-
sulphuric acid as easily as possible immediately it forms by preventing
it from dissolving in the soda solution.
DESCRIPTION OF THE APPARATUS.
Our improved process is effected in the most simple manner. We
operate in the same furnace, seen in Fig. 1 of the annexed Drawing, both
the transformation of the marine salt into sulphate of soda and also that
of sulphate of soda into sulphuret of sodium. The furnace is so con-
structed that the flame from the fire shall give up the greatest possible
quantity of caloric, for which purpose it is caused to traverse in the
direction indicated by the arrows. In the leaden boiler D, which is
supported by plates of iron, is placed a mixture of marine salt and
sulphuric acid; the vapours of the hydrochloric acid pass off by the earthen
tube D' in order to be condensed in apparatus not shown in the Drawing.
From the leaden boiler D the sulphate of soda which forms passes into
the part C of the furnace, where its calcination is effected, after which
the sulphate is caused to pass over the sole B next the fire, where it is
mixed with the charcoal necessary for transforming it into sulphuret;
there is also added from 3 to 4 per cent. of carbonate of lime in order to
prevent as much as possible the formation of polysulphurets. The
sulphuret, when once formed, is withdrawn from the furnace; the sub-
sequent operations follow the same course. As the vapours which dis-
engage from the sole c of the furnace where the calcination of the sulphate
is effected still contain hydrochloric acid, they pass through the earthen
tube E¹ into condensing apparatus, where they are deprived of their
acidity, and thence pass into the chimney.
The sulphuret when withdrawn from the furnace is thrown into the
boiler A, Fig. 2, where it is washed. A worm tube heated by steam heats
the water to a temperature of from 104 to 113 degrees Fahrenheit, in
order to dissolve the whole of the soluble parts. When the solution is
complete the liquors are allowed to rest in order to settle; they then
pass through cock B into a closed filter C, Fig. 5, containing a sheet iron
sieve pierced with holes, and containing fine grit mixed with charcoal,
intended for retaining the impurities of the sulphuret on passing out at
the bottom of the filter; the clear liquors pass through cock d into a

page_text: stone cistern G, whence the sulphuret in solution is raised by means of
a pump into the cistern F, which effects the distribution of the liquors
in the decomposing apparatus H, H', H³, Fig. 3, by means of cock a.
In commencing this operation we first introduce the milk of lime into
the first apparatus H by means of a funnel cock I, and then add the
sulphuret of sodium in solution; during the introduction of these matters
the small air-cock i is opened, in order to prevent the formation of a
vacuum. When the matters have been introduced into boiler A, a
current of carbonic acid is forthwith supplied to it produced by the coke-
burning apparatus, which is not represented in the Drawing. The current
of carbonic acid arrives by tube M, and is introduced in apparatus H
by tube N, which serves at the same time as an axis for the agitator O.
This agitator is set in motion by means of gearing X, and is in motion
during the whole time that the jet of carbonic acid is being supplied,
and thus prevents the deposit of lime and oxysulphuret of calcium. We
then ascertain whether the liquor is changed to a state of bicarbonate
of soda by withdrawing a little of it from the boiler H by means of
cock y. The salt is then filtered, calcined, and tested, either with normal
sulphuric acid or with a solution of nitrate of silver, which should indicate
in the salt obtained but slight traces of hyposulphite of soda. During
the operation the hydrosulphuric acid which disengages, as also the excess
of carbonic acid, passes into the second apparatus H', which is similar
to apparatus H, by means of a tube and cock J. This second apparatus
also contains a solution of sulphuret of sodium, intended to absorb any
excess of carbonic acid which may be disengaged in apparatus H. The
hydrosulphuric acid passes off by means of cock K from apparatus H',
and passing thence through the tube L, which is common to the whole
series of apparatus, is conducted into the furnaces for treating pyrites,
the position of which is indicated by the letter Z, where it is transformed
of sulphurous acid. This acid is then transformed into sulphuric acid
in leaden chambers, represented in the Drawing by letter Z¹. When
the operation is terminated in apparatus H, a current of carbonic acid
is passed into apparatus H', which in its turn communicates with
apparatus H, where the operation is continued as before described.
As the solution of bi-carbonate contained in the boiler H may still
retain a little hydrosulphuric acid in solution, we deprive it of the latter
by boiling the solution by means of a worm e, heated with steam. The
small cock F is opened, which introduces steam into the worm from a
generator supplied by means of a general pipe P, the water of condensa-
tion passes out through cock g and pipe h. The vapours of the hydro-

page_text: sulphuric acid and the water pass through the cock K' into a general
pipe L, which conducts them to the furnace containing the pyrites; before
opening the cock K", the cock J is closed, which communicates with the
apparatus H¹.
When the solution of bi-carbonate of soda has boiled for a few minutes,
the steam cock is closed, as also the cock K", the liquors are allowed
to rest in order that the carbonate of lime may settle at the bottom of
the boiler, and when the liquors are quite clear they are drawn off by cock
Q. The clear liquor is then conveyed by means of wood channels into the
cast-iron boiler E, placed in the furnace, Fig. 1, and after they have been
well concentrated in said boiler, they may be treated in two different
manners; thus they may be directly calcined in a reverberatory furnace
in order to obtain carbonate of soda, or they may be introduced into sheet-
iron boilers, in which the salt may be extracted by precipitation. The
mother-waters resulting from the latter process may afterwards be
crystallized. The thick liquors remaining in apparatus H are conveyed
by means of cock R into wood channel S, whence they pass into the
boiler, Fig. 4. In this boiler said matters are washed with boiling water,
and these weak waters charged with a little bi-carbonate of soda serve
instead of pure water for dissolving in boiler A, Fig. 2, the sulphuret of
sodium on its exit from the furnace. When the deposit of carbonate of
lime has been sufficiently washed, the exhausted matters are conveyed
away by means of cock Y through channel . These matters consist of
carbonate of lime in a nearly pure state. They may then be utilized for
the production of the lime necessary for decomposing the sulphuret, so
that the same lime may serve for an almost indeffinite length of time.
We may also, in order to economize the production of carbonic acid,
collect the said acid which is disengaged by the calcination of the
carbonate of lime in the gazometer, and so employ it for the decom-
position of the sulphuret of sodium. On leaving the boiler, Fig. 4, the
carbonate of lime is of a dull green color, but after being exposed a day
or two in the air, it becomes completely white. The apparatus may be
made of any desired dimensions, according to the purpose of the
manufacture.
It will be readily understood that the same process is applicable for
the manufacture of carbonate of potash by decomposing the sulphuret
of potassium. Our Invention also consists in the manufacture of salts
of potash in a similar manner.
In order the more readily to manufacture the sulphurets of
these two bases, instead of directly decomposing the sulphates

page_text: of potash and soda by means of the charcoal, we employ a solution
of sulphuret of barium for producing these two alkaline sulphurets.
We decompose natural sulphate of baryta in a reverberatory
furnace with charcoal, and thus obtain sulphuret of barium
soluble in water. We then mix this solution of sulphuret of barium
with a solution of sulphate of potash or of soda, and so extract
from the double decomposition which takes place a solution of sulphuret
of potassium or of soda, and also a white precipitate of artificial sulphate
of baryta, which after several washings in water is ready for the market.
The sulphuret of barium which is readily obtained in this manner, also
serves for purifying the hydrosulphuric acid on its exit from the decom-
posing vessels H, H³, H". In an apparatus similar to H we introduce
a solution of sulphuret of barium, which absorbs the excess of carbonic
acid disengaged from the other apparatus, and which might injure the
hydrosulphuric acid; a precipitate of artificial carbonate of baryta is thus
obtained, while the hydrosulphuric acid disengages in a pure state. This
acid is collected in a receiver or gasometer for distribution to the
apparatus for producing combustion, placed in the furnace with iron
pyrites. These apparatus consist of a number of gas jets, similar to those
used in laboratories, and composed of a large tube forming a general
receiver to the gas, to which are connected a great number of tubes of
smaller diameter, at the ends of which the hydrosulphuric acid will ignite
in the manner as gas.
Having described the nature of our Invention, and the manner of per-
forming the same, we declare that what we claim as our Invention to be
protected by the herein-before in part recited Letters Patent, is,—
First, the formation of carbonate of soda by transforming sulphuret
of sodium into bi-carbonate of soda, whatever may be the manner in
which the sulphuret of sodium is obtained, as herein-before described.
Secondly, the employment of lime or other oxydated agent capable of
answering similar purposes.
Thirdly, the arrangement of furnace and other apparatus represented
in the accompanying Drawing.
Fourthly, we claim the formation of carbonates of potash and soda by
transforming sulphurets of potassium & sodium into bi-carbonates of
similar bases.
Fifthly, we claim the preparation of sulphurets of potassium and sodium
by the decomposition of sulphuret of barium.
Sixthly, we claim the manufacture of sulphate and carbonate of barytą
in a similar manner.

page_text: Seventhly, we claim the application of a gas apparatus of any suitable
form for producing the combustion of the hydrosulphuric acid and for
transforming it into sulphuric acid.
Eighthly, we claim the use of steam for quickening the reactions.
And, ninthly, we claim the entire apparatus, which may be of any
suitable form and arrangement, for the transformation of the sulphuret
of barium into carbonate, and also for producing the combustion of the
hydrosulphuric acid in order to transform it into sulphuric acid, and also
the various modifications and improvements therein necessary for pro-
ducing the desired result.
In witness whereof, we, the said Louis Désiré Verstraet and Etienne
Maurice Olivier, have hereunto set our hands and seals, this Ninth
day of February, in the year of our Lord One thousand eight
hundred and sixty-three.
LOUIS DESIRE VERSTRAET. (L.s.)
E. M. OLIVIER.
(L.S.)