IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC ACIDA
Year: 1855

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, and of Glasgow, North Britain, Gentleman,
for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF SULPHURIC
ACIDA communication from Jean Francois Persoz, of Paris, in the
Empire of France, Chemist, Professor in the "Conservatoire des Arts et
Metiers."
Sealed the 10th July 1855, and dated the 11th May 1855.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents, with his Petition, on the
11th May 1855.
I, JOHN HENRY JOHNSON, of 17, Lincoln's Inn Fields, in the County of
Middlesex, and of Glasgow, North Britain, Gentleman, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
SULPHURIC ACID," a communication from Jean Francois Persoz, of Paris, in the
Empire of France, Chemist, Professor in the Conservatoire des Arts et Metiers,
to be as follows:-
This Invention relates to a peculiar system or mode of manufacturing
sulphuric acid, which system or mode is equallyapplicable to the manufacture
of sulphates and to the extraction of sulphur from metals and other bodies,
but more especially from copper, iron,lead, and antimony, whereby the process
[Price 8d.

page_text: is rendered more simple and economical than the processes hitherto adopted
for that purpose.
In carrying out this Iuvention two processes are employed: the first has for
its object the production of sulphurous acid, by one or other of the analytical
or synthetical reactions which will produce this gas, to be afterwards oxydized;
and the second process serves to destroy or decompose this sulphurous acid
by the aid of sulphuretted hydrogen & steam. In oxydizing sulphurous acid
two well-known processes are employed. The first consists in the employment
of nitric acid for oxidizing the sulphurous acid, and converting it into sui-
phuric acid. But the peculiarity in the present system consists in directing the
sulphurous acid through nitric acid, heated to a temperature of about 100°,
and previously diluted with from 4 to 6 times its volume of water; or the
sulphurous acid may be directed through a mixture of nitric & muriatic
acid.
The second process, which consists in the oxidation of nitrous vapour, or
chloro-nitrous vapour, and transforming it into nitric acid by means of the
oxygen obtained from the atmosphere, or from any other source. In oxydizing
nitrous vapour, and re-converting it into nitric acid at the same time that it
is decomposed, it is proposed to turn to account the well-kirown fact, that
in several experiments performed in the presence of water or its vapour, four
volumes of nitrous vapour & one volume of oxygen will combine and form
nitric acid. This may be effected either in the same chamber where the
sulphurous acid is oxidized, in order to accumulate the strong sulphuric acid
or in a chamber communicating therewith when oxidation can no longer be
advantageously accomplished in the first chamber. By this system or mode
of manufacturing sulphuric acid the leaden chambers hitherto employed are
dispensed with. Sulphurous acid gas, disengaged by any of the reactions
capable of producing it, may also be employed, either pure or mixed with
nitrogen, carbonic acid or oxide, and hydrogen, for making sulphuric acid by
the improved process, as well as from sulphurous acid produced from the com-
bustion of sulphur & certain qualities of pyrites. By this process also the
nitrates of potash and soda and the chlorides of the same may be converted
into sulphates of potash and soda, both one and the other being previously
dissolved in water, to which, in the case of the nitrates, a certain quantity of
muriatic acid has been added, and in the case of the chlorides, nitric acid,so as
to develope ineachcase the chloro-nitrous vapour, for the purpose of transform-
ing into sulphuric acid the volumes of sulphurous acid necessary forconverting
into a sulphate the entire base of the nitrate or chloride employed. The liquid
is now concentrated in the distilling chambers, to expel the excess of hydro-

page_text: chloric and nitric acids. The process just described with regard to the salts
produced by the alkaline oxides of certain metals may be applied with equal
success to any other nitrate or chloride.
Sulphurous acid mayalso be used which has been obtained from the following
sources:-1st, sulphurous acid produced by the roasting of all kinds of minera!
sulphurets, care being taken, however, to condense all those vapours which
are susceptible of condensation, such as that of arsenious acid, in proper
chambers, before directing the sulphurous acid through the nitric acid; 2nd
sulphurous acid produced by the reaction of sulphuric acid, or that obtained
from bisulphate of potash or soda upon certain metals or natural sulphurets or
arsenio sulphurets; 3rd,sulphurous acid produced by the reaction of the sul-
phates of iron, zinc, and copper on the corresponding sulphurers of these
metals, at proper temperatures and in suitable distilling chambers; 4th, sul-
phurous acid produced by the reaction of the sulphates of iron, zinc, and
copper,either upon charcoal and certain organic matters, or upon hydrogen or
carbonic oxide, or upon any of the carburets of hydrogen, either gaseous,
liquid, or solid. This decomposition should be effected with any of the sul-
phates at such a temperature as will decompose the sulphuric acid, and expel
it in the form of sulphurous acid gas, so that there only remains the metal, or,
possibly, a metallic oxide, which can, by the addition of a proper quantity of
charcoal and heat, be converted into metal. Thus, by heating the sulphate of
copper to about 220° or 250°, in a current of hydrogen, or of hydrogen more
or less carburretted, the whole of the sulphuric acid disappears in the form
of sulphurous acid, mixed with carbonic acid, and there remains as a residue
pure copper, or copper mixed with sulphates of iron and zinc. 5th, sulphurous
acid produced by the reaction of hydro-chloric acid gas on sulphate of lime;
6th,sulphurous acid produced by the combustion of impure sulphur,obtained
as a residue after the treatment of certain natural sulphurets by nitric acid.
On the contact with water or its vapour, sulphurous acid gus and sulphur-
retted hydrogen mutually decompose one another, and give rise, 1st, to a
deposition of sulphur; 2nd, to a certain quantity of sulphuric acid; 3rd, to
a large proportion of hyposulphurous acid, which is destructible by heat, which
decomposes it into sulphur, sulphurous and sulphuric acids, or which, treated
with nitric acid or the vapour of nitrous acid, is immediately transformed into
sulphur and sulphuric acid. It is proposed to apply these reactions in the
following cases-1st, when the roasting of the mineral sulphurets give rise
to a gas containing only a small proportion of sulphurous acid, which can be
oxidized with advantage by means of the nitric acid process above described;
2nd, when it is necessary to decompose the artificial or natural sulphurets by

page_text: an acid, to assist either the extraction of the sulphur or of the metal. The
reaction of the gases may be effected in the apparatus herein-after described.
In the first process relating to the production of sulphurous acid, it is pro-
posed to employ all the apparatus used in the distillation of organic matters
and of coal. They serve for the roasting and oxidation of minerals, with or
without having recourse to a blowing apparatus.
In the second process, which consists in bringing in to the most immediate
possible contact the sulphurous acid gas and nitric acid, all the forms of appa-
ratus for the purpose of bringing gas into contact with a liquid are suitable.
The material of which the vessels should be made is limited. It is proposed
to use lava, granite, glass, such earth as is not attacked by acid, stoneware,
natural and artificial hardened caoutchouc, gutta percha, and any other sub-
stance not attacked by a mixture of nitric and sulphuric acids or by the
vapour of nitrous acid.
The third process has a double object; 1st, to increase the number of
points of contact between the vapour of the nitrous acid, the air, & the water
or its vapour, so that the nitric acid may be almost as soon remade as decom-
posed; 2nd, to deprive the nitrogen, the air, and the carburretted gases which
have accompanied the sulphurous acid, of the nitric acid vapour which they
hold in suspension. For this purpose, all the apparatus employed for purify-
ing gas from any matters soluble in water may be employed. But in this
Invention the double object is accomplished by means of an agitator placed
in the vessel in which the sulphurous acid is oxidysed, & a chimney to which
the necessary height can be given, in order that the gas which rises through
it, and passes through porous substances, kept wet by a stream of water, may
be deprived of any nitric acid it may hold in suspension.
The apparatus I prefer to employ is composed of three distinct parts. The
first part varies in its form and arrangements according to the materials
used for the production of the sulphurous acid necessary to the preparation of
sulphuric acid; the second part is to enable the sulphurous acid to come
in contact with the nitric aci 1, diluted with from 4 to 6 times its volume of
water; and the third part consists of a chimney containing porous material,
in which all the gaseous bodies which have escaped the reaction produced in
the second part complete their mutual action, & effect a last analyses of the
nitric acid, which, charged with a little sulphuric acid, is carried away by a
stream of water, and is delivered into a suitable reservoir.
The form & size of the 3 parts of the apparatus may vary considerably,
and may receive in practice modifications, more or less important, according to
the precise work they have to perform. Thus, for the combustion of sulphur,

page_text: which cannot be performed in the open air as in the ordinary process, it
is proposed to have recourse to a cast-iron cylinder, or what is better, to an
earthen retort, of the same kind as those used for distillation in the manu-
facture of gas. These retorts are the combustion chambers, & are heated by
ineans of the fire below them. At one extremity a tube is introduced, through
which air is supplied by means of a blowing machine of any suitable form,
while from the other extremity of the retort the sulphurous acid gas is carried
away by another pipe, which conduct it to the nitric acid, where it is oxidized.
But when the combustion of the sulphur is effected in this manner, that is
to say, in a vessel containing a limited volume of air in motion, it becomes
important to prevent the volatilization of the sulphur.
But it is proposed to adopt an arrangement which, although it favors the
oxidyzing influence of the air,at the same time prevents its mechanical effects.
A series of porous earthen tubes are introduced into the upper part of the
retort,open at their upper ends, which should project two or three inches above
the retort, aud closed at their lower extremities, which should be inside the
retort. These cylinders,having been previously well luted to the openings in
the retort made to receive them, are filled with sulphur. If the retort is
now heated, the sulphur, soon entering into fusion, will leak through the
pores of the tubes, and, falling into the heated retort, will be burnt therein.
Thus the part of each tube which is in the retort will be surrounded with
flame, which will be kept regularly up by the air which is introduced, and by
the dripping of the sulphur which filters in, in the same manner as the water
in a water cooler. The tube for carrying off the gas, instead of being directed
straight to the mixing chamber, communicates with an intermediate vessel
composed of earth,stone, or any other suitable material. This vessel contains
also a vertical tube, which is furnished with a cock, to introduce such a
quantity of air as will contain a volume of oxygen equal to about half of
that of the sulphurous acid supplied from the retort. An other tube is also
fitted to this vessel, which conducts the air and acid to the mixing chamber,
spreading it out equally through the liquid by means of a quantity of small
holes pierced in the lower part of the tube immersed in the liquid. This
liquid is composed of nitric acid & water, and the mixture is constantly
agitated by an agitator, which is driven from the outside at a convenient
velocity.
The receiver which encloses the whole is made in two pieces, in order to be
taken to pieces aud put together again with facility. It can be heated by
means of water, steam, or hot air, or by a fire for that purpose. At its base
is a cock, which allows the mixture to be drawn off when requisite, and at

page_text: its upper part there is a tube, which being prolonged, enters the bottom of
the chimney before mentioned. Several openings may be formed round the
base of the chimney to receive tubes, and its base is prolonged downwards
in order to enter a basin or cistern which is furnished with a waste pipe
to carry away the excess of nitric acid.
The interior of the chimney or regenerator is divided by partitions pierced
with holes, which serve to support the porous material before referred to, and
through which pass the acids which have just been mixed. The chimney
receives a jet of water at its upper part, which carries down the nitric acid
into the lower basin. A similar chimney in communication with the first
completes the operation, by forcing the gas to descend the chimney by means
of an exhausting machine in cominunication therewith. Asimilar basin to the
preceding one,and furnished a lso with a waste pipe, receives the nitric acid,
together with a small quantity of sulphuric acid that may still remain with it
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Henry Johnson in the Great Seal Patent Office on
the 10th November 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
and of Glasgow, North Britain, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of May, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors give and grant unto me,
the said John Henry Johnson, Her special license that I, the said John
Henry Johuson, my executors, administrators, and assigns, or such others
ds I, the said John Henry Johnson, my executors, administrators, or 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 SULPHURIC ACID," a cominunication from Jean Francois
Persoz, of Paris, in the Empire of France, Chemist, Professor in the "Cou-
servatoire des Arts et Metiers," upon the condition (amongst others) that I,
the said John Henry Johnson, by an instrument in writing under my hand

page_text: and seal, 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 mouths
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that J, the said John Henry Johnson, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the fol-
lowing statement, reference being had to the accompanying Drawings, and
to the lettera and figures marked thereon, that is to say:
The said Invention relates to a peculiar system or mode of manufacturing
sulphuric acid, which system or mode is equally applicable to the manufacture
of sulphates and to the extraction of sulphur from metals and other bodies,
whereby the process is rendered more simple and economical than the processes
hitherto adopted.
In
In carrying out this Invention two processes are employed. The first
has for its object the production of sulphurous acid by one or other of the
analytical or synthitical reactions which will produce this gas, to be
afterwards oxydized; and the second process serves to destroy or decompose
this sulphurous acid by the aid of sulphuretted hydrogen and steam.
oxydizing sulphurous acid, two well-known processes are employed. The first
consists in the employment of nitric acid for oxidizing the sulphurous acid,
and converting it into sulphuric acid. But the peculiarity in the present
system consists in directing the sulphurous acid through nitric acid heated 10
a temperature of about 100°, and previously diluted with from to six times
its volumn of water; or the sulphurous acid may be directed through a mixture
of nitric or muriatic acid.
The second process, which consists in the oxidation of nitrous vapour or
chloro-nitrous acid, and transforming it into nitric acid, by means of the
oxygen obtained from the atmosphere or from any other source. In oxidizing
nitrous vapour, and re-converting it into nitric acid at the same time that it is
decomposed, it is proposed to turn to account the well-known fact, that in
several experiments performed in the presence of water or its vapour, four
volumns of nitrous vapour and one volume of oxygen will combine and form
nitric acid. This may be effected either in the same chamber where the
sulphurous acid acid is oxidized in order to accumulate the strong sulphuric
acid, or in a chamber communicating therewith when oxidation can no
longer be advantageously accomplished in the first chamber. By this system
or mode of manufacturing sulphuric acid, the leaden chambers hitherto
employed are dispensed with. Sulphurous acid gas, disengaged by any of the

page_text: reactions capable of producing it, may also be employed, either pure of
mixed with nitrogen, carbonic acid or oxide, and hydrogen, for making
sulphuric acid by the improved process, as well as from sulphurous acid
produced from the combustion of sulphur and certain qualities of pyrites. By
this process also the nitrates of potash and soda, and the chlorides of the
same, may be converted into sulphates of potash and soda, both one and the
other being previously dissolved in water, to which, in the case of the nitrates
and a certain quantity of muriatic acid has been added, and in the case of
the chlorides nitric acid, so as to develope in each case the chloro-nitrous
for the purpose
of transforming into sulphuric acid the volume of
sulphurous acid necessary for converting into a sulphate the entire base
of the nitrate or chloride employed. The liquid is now concentrated in the
distilling chambers, to expel the excess of hydrochloric and nitric acids.
The process just described with regard to the salts produced by the alkaline
oxides of certain metals may be applied with equal success to any other nitrate-
or chloride.
vapour,
Sulphurous acid may also be employed obtained from the following
sources: first, sulphurous acid produced by the roasting of all kinds of
mineral sulphurets, care being taken, however, to condense all those vapours
which are susceptible of condensation, such as that of arsenious acid, in
proper chambers, before directing the sulphurous acid through the nitric acid;
second, sulphurous acid produced by the reaction of sulphuric acid, or that
obtained from bisulphate of potash or soda upon certain metals or natural
sulphurets or arsenio-sulphurets; third, sulphurous acid produced by the
reaction of the sulphates of iron, zinc, and copper, on the corresponding
sulphurets of these metals at proper temperatures and in suitable distilling
chambers; fourth, sulphurous acid produced by the reaction of the sulphates
of iron, zinc, and copper, either upon charcoal and certain organic matters, or
upon hydrogen or carbonic oxide, or upon any of the carburets of hydrogens,
either gaseous, liquid, or solid. This decomposition should be effected with
any of the sulphates at such a temperature as will decompose the sulphuric
acid, and expel it in the form of sulphurous acid gas, so that there only
remains the metal or possibly a metallic oxide, which can by the addition
of a proper quantity of charcoal and heat be converted into metal. Thus,
by heating the sulphate of copper to about 220 or 250° in a current
of hydrogen, or of hydrogen more or less carburretted, the whole of the
sulphuric acid in the sulphate disappears in the form of sulphurous acid mixed
with carbonic acid, and there remains as a residuum pure copper, or copper
mixed with sulphates of iron and zinc. Fifth, sulphurous acid produced by

page_text: the reaction of muriatic gas on sulphate of lime; sixth, sulphurous acid
produced by the combustion of impure sulphur obtained as a residue after the
treatment of certain natural sulphurets by nitric acid.
On the contactwith water or itsvapour, sulphurous acid gas and sulphuretted
hydrogen mutually decompose one another, and give rise, first, to a deposition
of sulphur; second, to a certain quantity of sulphuric acid; third, to a large
proportion of byposulphurous acid, which is destructible by heat, which
decomposes it into sulphur, sulphurous and sulphuric acids, or which, treated
with nitric acid or nitrousvapour, is immediately transformed intosulphur and
sulphuric acid. It is proposed to apply these reactions in the following cases: -
First, whenthe roasting of the mineral sulphurets give rise to a gas containing
only a small proportion of sulphurous acid, which can be oxidized with
advantage by means of the nitric acid process above described; second, when
it is necessary to decompose the artificial or natural sulphurets by an acid, to
assist either the extraction of the sulphur or of the metal. The reaction of
the gases may be effected in the apparatus herein-after described.
In the first process relating to the production of sulphurous acid, it is
proposed to employall the apparatus used in the distillation of organic matters
and of coal. They serve for the roasting and oxidation of minerals, with or
without having recourse to a blowing apparatus.
In the second process, which consists in bringing the most immediate
possible contact the sulphurous acid gas and nitric acid, all the forms of
apparatus for the purpose of bring gas into contact with a liquid are
suitable. The material of which the vessels should be made is limited. It is
proposed to use lava, granite, glass, such earth as is not attacked or affected
by acid, stoneware, natural and artificial hardware caoutchouc, gutta percha,
and any other substance not attacked or affected by a mixture of nitric and
sulphuric acid, or by the vapour of nitrous acid.
The third process has a double object; first, to increase the number of
points of contact between the vapours of the nitrous acid, the air, and the
vater or its vapour, so that the nitric acid may be almost as soon remade
s decomposed; second, to deprive the nitrogen, the air, and the carburetted
gases which have accompanied the sulphurous acid, of the nitric acid vapour
which they hold in suspension. For this purpose all the apparatus employed
or purifying gas from any matters soluble in water may be employed; but
n this Invention the double object is accomplished by means of an agitator
laced in the vessel, in which the sulphurous acid is oxidysed, and a chimney
o which the necessary height can be given, in order that the gas which rises

page_text: through it, and passes through porous substances kept wet by a stream of
water, may be deprived of any nitric acid it may hold in suspension.
The apparatus which I prefer to employ is composed of three distinct parts,
A, B, and C, on the annexed Sheet of Drawings. The first part. A varies in its
form and arrangements according to the materials used for the production of
the sulphurous acid necessary to the preparation of sulphuric acid. The second
part B is to enable the sulphurous acid to come in contact with the nitric acid,
diluted with from four to six times its volume of water. And the third part
C consists of a chimney containing porous material, in which all the gaseous
bodies which have escaped the reaction produced in the second part enter by
the openings o, and complete their mutual action, and effect a last analysis of
the nitric acid, which, charged slightly with sulphuric acid, is carried off by a
stream of water, and is delivered into a suitable reservoir P.
The form and size of the three parts of the apparatus may vary considerably,
and may receive in practice modifications, more or less important, according to
the precise work which they have to perform. Thus, for the combustion of
sulphur, which cannot be performed in the open air as in the ordinary process,
it is proposed to have recourse to a cast-iron cylinder, or, what is better, to an
earthen retort d, of the same kind as those used in the manufacture of gas.
These retorts are the combustion chambers, and are heated by means of the
fire g below them. At one extremity a tube e is introduced, through which air
is supplied by means of a blowing machine of any suitable form, whilst from
the other extremity of the retort the sulphurous acid gas is carried away by
another pipe, which conducts it to the nitric acid, where it is oxydized. But
where the combustion of the sulphur is effected in this manner, that is to
say, in a vessel containing a limited volume of air in motion, it becomes
important to prevent the volatization of the sulphur. But it is proposed to
adopt an arrangement which, although it favours the oxydizing influence,
the air at the same time prevents its mechanical effects. A series of porous
earthen tubes c, c, are introduced into the upper part of the retort, open at
their upper ends, which should project two or three inches above the retort,
and closed at their lower extremities, which should be inside the retort.
These cylinders, having been previously well luted to the openings in the
retort made to receive them, are filled with sulphur. If the retort is now
heated,the sulphur,soon entering into fusion,will leak through the pores of the
tubes, and falling into the heated retort will be burnt therein. Thus the part
of each tube which is in the retort will he surrounded with flame, which will
be kept up by the air which is introduced, and by the dripping of the sulphur,

page_text: which filters through in a similar manner to the water in a water cooler. The
tubef for carrying off the gas, instead of being directed straight to the mixing
chamber B, coinmunicates with one of the three branches of the inter.
mediate vessel serving as an indicator, and composed of earthenware, glass,
stone, or other suitable material. This vessel contains also a vertical air tubej,
which is furnished with a cock to introduce such a quantity of air as will
contain a volume of oxygen equal to about half of that of the sulphurous
acid supplied from the retort. Another tube f' is also fitted to this vessel,
which conducts the air and acid to the mixing chamber B, spreading it out
equally through the liquid by means of a quantity of small holes pressed in the
lower part of the tube which is immersed therein. This liquid is composed
of nitric acid and water, and the mixture is constantly agitated by an
agitator K, which is driven from the outside at a convenient speed.
The receiver B, which encloses the whole, is made in two parts, in order to
be taken to pieces, and put together again with facility. It may be heated by
means of water, steam, or hot air, or by a fire for that purpose. At its base
is a cock el, which allows the mixture to be drawn off when requisite, and at
its upper part there is an opening m which receives the tube n, such tube
being prolonged and entering the bottom of the chimney C, before mentioned.
Several openings o may be formed round the base of the chimney, to receive
the tubes ; and the base of the chimney is prolonged downwards, in order
to enter the basin or cistern p, which is furnished with a waste pipe q to carry
away the excess of the nitric acid into the vessel r.
The interior of the chimney or regeneratorC is divided by the partitions 8, 8,
pierced with holes, which serve the support the porous material before referred
to, and through which pass the acids which have just been mixed. The
chimney receives a jet of water at its upper part t, which carries down the
nitric acid into the lower basin p. A.similar chimney C', in communication
with the first one, completes the operation, by forcing the gas to descend the
chimney by means of an exhausting machine in communication therewith by
the tube u. A basin p', similar to the preceding one, and furnished also
with a waste pipe q', receives the nitric acid, together with any small amount
of sulphuric acid that it may still contain.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that I do not confiue or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without

page_text: deviating from the principles or main features of the said Invention; but.
what I consider to be novel and original, and therefore claim as the Invention
secured to ine by the herein-before in part recited Letters Patent, is,
First, the peculiar system or mode of manufacturing sulphuric acid and
sulphates, as herein-before described.
Second, the general construction and arrangement of apparatus for inanu
facturing sulphuric acid and sulphates, or for extracting sulphur and various
metals, but more especially copper, iron, lead, and antimony, as herein-before
described.
In witness whereof, I, the said John Henry Johnson, have hereunto set
my hand and seal, this Tenth day of November, One thousand eight
hundred and fifty-five.
J. HENRY JOHNSON. (L.B.)