IMPROVEMENTS IN THE MANUFACTURE OF SULPHOCYANIDES AND FERROCYANIDES, AND IN APPARATUS TO BE USED THEREFOR
Year: 1881

page_text: LETTERS PATENT to Henry Edward Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Civil Engineer, for an
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF SULPHOCYANIDES
AND FERROCYANIDES, AND IN APPARATUS TO BE USED THEREFOR."
A com-
munication from abroad by Ury de Günzburg and Joseph Tcherniac, both of
Paris, in the Republic of France.
.
PROVISIONAL SPECIFICATION left by the said Henry Edward Newton at
the Office of the Commissioners of Patents on the 22nd March 1881.
HENRY EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Civil Engineer. "IMPROVEMENTS IN THE MANUFACTURE
OF SULPHOCYANIDES AND FERROCYANIDES, AND IN APPARATUS TO BE USED
THEREFOR." [A communication from abroad by Ury de Günzburg and Joseph
Tcherniac, both of Paris, in the Republic of France.]
The object of this Invention is to produce sulphocyanides and ferrocyanides in a
more economical manner than heretofore.
In manufacturing sulphocyanide of ammonia according to this Invention the
following apparatus is necessary, viz. :—
1. A force pump made of iron, and analogous to those used in the ammoniacal
process of manufacturing ice.
2. A series of heating vessels in forged iron, and proved to a high pressure.
Each of these vessels is provided with an agitator, a manometer, a thermometer,
and three cocks, two of which are for the admission and discharge of liquids
respectively, and the third for the exit of the gases which accumulate. in the vessel
during working. These vessels are surrounded for about three-quarters of their
height with a steam jacket, and they communicate through pipes with the pump
and with a still.
3. A still heated internally by a steam coil. This still communicates by a pipe
with a cylindrical vessel placed above it, and in which complete separation of the
vapor arising from the still and the solution carried over with it in a frothy state
is effected.

page_text: .
The result of the separation will be that the vapour ammoniacal gas and
sulphuretted hydrogen will pass off together through a second tube, while the
liquid particles will return by a third tube to the still..
4. A surface condenser surmounted by a column of coke, the whole placed above
à spacious receiver. A small force pump is used to draw up the liquid in the
receiver and throw it in the form of a continuous spray on the top of the column
of coke. This pump by keeping up a current of liquid through the condenser
causes a complete condensation of the ammoniacal vapour, and prevents obstructions
due to the crystallization of sulphide of ammonia.
5. A second receiver provided with a surface condenser and a column of coke
like the last named to retain the liquid particles which may be carried over.
6. A gas holder of a size to hold about 25 cubic metres, and which acts as a
regulator. The action of the above named apparatus is as follows:-
The series of heating vessels are charged with sulphide of carbon, ammonia, and
a certain quantity of ammoniacal liquor drawn from the still. This mixture is
heated under agitation to between 120° and 130° degrees centigrade by steam.
The steam is then shut off, but the agitating is continued until the manometer
registers 15 atmospheres, when a cock is opened and the liquid passes by a tube to
the still.
The liquids coming from the heating vessels (ammoniacal solution of sulpho-
carbonate of ammonia) reunite in the still, and are there heated to from 105° to
110° centigrade. At this temperature the sulphocarbonate of ammonia is decomposed
into sulphuretted hydrogen and sulphocyanide of ammonia. A small quantity of
sulphide of carbon is regenerated and distils with the vapour. This latter is
composed of sulphuretted hydrogen, sulphide of ammonia, sulphide of carbon, and
water, and by. its passage through the condenser leaves there the sulphide of
ammonia and the water and the sulphide of carbon (principally in the state of
sulphocarbonate, while the sulphuretted hydrogen alone passes to the gas holder,
from whence it is taken to a furnace to be converted into sulphuric acid, or is
treated with alkaline lye, which absorbs it.
The solutions of sulphocyanide of ammonia concentrated in the still are
evaporated if it be desired to form crystals.
It is preferred that all parts of the apparatus, with the exception of the still, should
be made of iron, but the still is to be made of aluminium, for certain acids given
off during evaporation in the still have a great affinity for iron, and the result is
a ferruginous salt. Tin and platinum may be used for the coil instead of aluminium,
but the one requires constant renovation, and the other is too costly. By the use
of aluminium a cheap and durable apparatus is obtained, and which is not affected
by the acid fumes given off during evaporation.
In the manufacture of sulphocyanide of calcium the following apparatus will
be used:-1st, a distilling vessel heated by a coil, and enclosing a basket to carry
the lime. This vessel is provided with a thermometer and an emptying cock, and
it communicates by two pipes with, 2ndly, a separating vessel, such as described
above; 3rdly, a surface condenser and, 4thly, a vessel containing a coil for cooling
by a current of water the liquids which absorb the excess of ammoniacal gas
disengaged toward the end of the operation.
The distilling reservoir is charged with solutions of sulphocyanide of ammonia
drawn from the still, and the necessary quantity of lime is introduced into the
basket. The vessel is then closed and heated rapidly to 130° centigrade. The
ammoniacal liquid distils and condenses in the condenser and runs down into the
receiver by a tube. The separator is indispensable as solutions of sulphocyanide
of calcium froth up enormously and pass with great rapidity to the condenser if
not intercepted. In the intercepting vessel the separation is remarkably complete,
the sulphocyanide of calcium returns continually to the reservoir, while the watery
ammoniacal vapor alone is admitted to the condenser.
The manufacture of sulphocyanide of potassium is carried on in open boilers,
suitably heated and provided with stirring apparatus. A concentrated boiling

page_text: solution of sulphate of potassium is prepared. To this while boiling is added in
small quantities sulphocyanide of lime; the sulphate of lime will deposit rapidly
on being allowed to stand. The solution of sulphocyanide of potassium is separated
by decantation and systematic washing or by filtration.
The solution obtained will still contain a little of the sulphocyanide of calcium,
and to remove this the liquid may be crystallized, or a small quantity of carbonate
of potassium may be added, which will cause the lime to precipitate. The clarified
or filtered solution is evaporated, and on cooling all the sulphate or chloride which
it contains will be deposited, and pure sulphocyanide of potassium will remain.
Prepared thus the sulphocyanide of potassium does not contain either lime or
sulphuric acid, two 'impurities which render it totally unsuited to be transformed
economically into a ferrocyanide.
In manufacturing ferrocyanide of potassium the desulphurisation of the sulpho-
cyanide of potassium is effected by fusing the latter with pulverised scrap iron free
from rust and impurities.
It has been found that the desulphurisation commences at the temperature of
about 360° centigrade, or the boiling point of mercury, and is completed at about
450° centigrade, or the boiling point of sulphur.
This being the case the sulphocyanide of potassium having been intimately
mixed with the pulverised scrap iron is placed in suitable crucibles or other vessels.
These crucibles are then placed in a suitable receiver which is enclosed in another
vessel and containing sulphur. The sulphur is made to boil and kept at boiling
point for several hours. The crucibles are then withdrawn, and the contents are
allowed to cool sheltered from the air.
The mass is then treated by any of the known processes to obtain the ferrocyanides
of potassium.
Instead of mixing the materials before the fusion takes place the mixing may be
effected in the same vessel and during fusion.
To this end a bath of sulphur in the form of crucible is employed. This vessel
is open at bottom, and is provided with a suitable stopper or plug and a stirrer.
The sulphocyanide of potassium is introduced into this vessel, and when it is
heated to the proper temperature the pulverised iron is added and the stirrer is set
to work.
When the fusion is effected the stopper or plug is withdrawn, and the contents
of the vessel are allowed to run into a pit or other receptacle where they can cool
sheltered from the air.
A bath of lead may be employed instead of sulphur, but it requires greater care
and attention to keep up the temperature.
Other sulphocyanides may be converted into ferrocyanides, as, for instance,
sulphocyanide of sodium.
It may be remarked that the sulphocyanides of alkaline metals are desulphurised
not only by iron but by nearly all the metals, under conditions similar to those
above described. This fact possesses great importance with regard to metals the
sulphides of which are not soluble in cyanide of potassium, since they permit of
the production of the cyanide of potassium direct without passing through the
stage of ferrocyanide. Thus, for instance, good results have been obtained by
mixing the sulphocyanide of potassium with finely pulverized lead at a temperature
of 450° centigrade.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Edward Newton in the Great Seal Patent Office on
the 22nd September 1881.
HENRY EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex. "IMPROVEMENTS IN THE MANUFACTURE OF SULPHOCYANIDES
AND FERROCYANIDES, AND IN APPARATUS TO BE USED THEREFOR.". A communi-
cation from abroad by Ury de Günzburg and Joseph Tcherniac, both of Paris,
in the Republic of France.
The object of this Invention is to produce sulphocyanides and ferrocyanides in a
-
The following apparatus is necessary for the manufacture of this product:-
1st. A force pump in iron analogous to those which are employed in the manu-
facture of-ice by the ammonia process.
2nd. A series of heating vessels in wrought iron and proved to a high pressure.
Each vessel is provided with an agitator, a manometer, a thermometer, and three
cocks intended, one to allow the entrance of liquids coming from the pump, another
to permit as required the passage of the gas accumulated in the vessel, and the
third for emptying the vessel. The heating vessels are surrounded for about three
quarters of their height by a steam jacket. They communicate with each other,
with the pump, and with a still by a system of pipes. Each manometer, the
flexible part of which ought to be of iron or platinum, is provided with a tube
which enters the liquid in the heating vessel. Without this precaution the mano-
meters are soon rendered false by the deposition of sulphide of ammonia on the
diaphragm in the curved tube.
3rd. A still heated by a steam coil in the bottom thereof.
This still is surmounted by a cylindrical vessel which constitutes an important
part of it, and which may be called the separator. In this vessel a complete
separation of the vapor coming from the still, and the solution which is carried
over with it in a frothy state takes place.
The frothy vapour passes from the still to the separator by a tube which projects
into the separator for about twenty centimeters. The frothy vapour there separates
completely into steam, ammoniacal gas, and sulphuretted hydrogen, which all
escape by a tube connected with the top of the separator, while the particles of
liquid carried over reunite and return to the still by another pipe which extends
nearly to the bottom thereof. This apparatus gives excellent results, it is of a very
simple construction, and is suitable for various manufactures, and it is therefore
desired to claim its use for all cases whatsoever in which it is required to obtain a
complete separation between a vapor and a liquid carried over in a state of froth
or spray. Thus it would be very useful for steam generators or dry steam being
thereby obtained with very small expenditure of fuel.
4th. A surface condenser of any known form surmounted by a column of coke and
situated above a spacious receiver. A small force pump is used to raise the condensed
liquid from the receiver and throw it in spray on to the top of the column of coke.
By thus causing a current of liquid to pass through the condenser the complete
condensation of the ammoniacal vapor is ensured, and any obstruction due to the
crystallization of the sulphide of ammonia in the condenser is prevented.
5th. A second receiver provided with a condenser and column of coke analogous
to the preceding but arranged inversely, and which ensures the retention of any liquid

page_text: portions which may have been carried over. 6th. A gas holder of the capacity of
about twenty five cubic metres, and which takes the office of a regulator.
The apparatus acts in the following manner :-
The pump feeds the heating vessels with sulphide of carbon, ammonia, and a
certain quantity of ammoniacal liquor proceeding from the condensation of the
waters of distillation of the still.
As soon as one vessel has received its charge the in-flow cock is closed and the
agitator or stirrer is put in motion. The liquid is heated by means of steam, until
the thermometer placed in a tube filled with oil and plunged in the liquid registers
120 to 130 degrees centigrade.
The steam is then shut off and the agitation is continued until the manometer
indicates 15 atmospheres.
At this moment the operation being nearly terminated the agitation is stopped
and the emptying cock is opened.
The liquid is caused by the pressure to escape by the tube which extends to the
bottom of the heating vessel and enter the still. The pressure may be raised to a
higher figure, or the liquid may be maintained during a lengthened period at a
pressure of 15 atmospheres by opening occasionally the cock which gives exit to the
gas.
The liquids coming from the heating vessels, the ammoniacal solutions of sulpho-
carbonate of ammonia re-unite in the still, and are there heated to 105 to 110
degrees centigrade. At this temperature the sulpho-carbonate of ammonia decom-
poses into sulphuretted hydrogen and sulphocyanide of ammonia, a small quantity
of sulphide of carbon is regenerated and distils with the vapor. This latter is
composed of sulpburetted hydrogen, sulphide of ammonia, sulphide of carbon and
water. During its passage through the condensers and the receivers it leaves there
the sulphide of ammonia and the water, and the sulphide of carbon (principally in
the state of sulpho carbonate), whilst the sulphuretted hydrogen alone passes to
the gas holder. From the gas holder it is passed either to a furnace to be converted
into sulphurous acid, or into alkaline lyes which absorb it.
The solutions of sulpho cyanide of ammonia concentrated in the still at 105 to
110 degrees centigrade are evaporated at 125° if it is desired to obtain crystals.
The feed pump, the heating vessels, and their communications should be made of
iron either wrought or cast. Iron is but slightly attacked by ammonia or the
solutions of sulphide of ammonia. The heating vessel need not even be enamelled.
The same metal serves for the condensers and the receivers as well as for the gas
holder.
The still only with the separator and its accessories ought not to be in iron,
unless it be desired to obtain solutions of sulpho cyanide of ammonia heavily
charged with sulpho cyanide of iron, and giving by evaporation crystals which
redden strongly on contact with air by the oxidation of the ferruginous salts. The
reason of the attack which takes place on the iron is the gradual conversion of a
small quantity of sulphocyanide of ammonia into ammonia and sulphocyanhydric
acid, so soon as the liquid.bas lost by the distillation the sulphide of ammonia
which exerts on the iron a protective action. The sulphocyanhydric acid set at
liberty dissolves a corresponding proportion of iron and produces the ferruginous
salt. The quantity of iron dissolved is in inverse relation to the rapidity of the
evaporation.
The chances of the attack on the apparatus may be greatly reduced by making
the coil which constitutes the most exposed portion of the apparatus of tin. This
latter metal resists to a greater extent than iron the action of sulphocyanhydric
acid. The solutions obtained by the aid of an apparatus of this kind will contain

page_text: only some milliemes of iron, but still sufficient to tarnish the crystals obtained by
evaporation. However the tin although more durable than the iron wears away
rapidly enough, and having to be continually replaced becomes costly. The use of
platinum is out of the question because. of its high price and the large quantity
that would have to be used to get the necessary thickness of apparatus to resist 5
alternately pressure and vacuum.
There is however a metal which suitably prepared fulfils all the conditions
necessary for making durable and strong stills and evaporating vessels. This metal
is aluminium. Prepared with care, and cleaned from the scorice which it contains
by a thorough rolling and hammering it develops a resisting force which is proof 1
against any pressure obtained during the evaporation of the solutions of the sulpho
carbon. By constructing the still with its accessories of aluminium an apparatus
is obtained which will last a long time, and by its use the solutions of sulpho
cyanide of ammonia will be obtained, so to speak, chemically pure. The employ-
ment of aluminium for the apparatus in which the evaporation of sulpho carbonic 1
and ammoniacal solutions in general are carried on is also claimed, as it is
demonstrated that contrary to preconceived ideas purified aluminium is unattackable
by ammonia and by sulphuretted hydrogen allied with ammonia.
If it be desired to obtain pure crystals of sulphocyanide of ammonia, which
will remain white on exposure to air, and from liquids proceeding from an iron 2
still, and consequently charged with iron salts, the solutions should be treated
before being evaporated in a vessel made of tin, or better still of aluminium, by
the sulphide of ammonia. The waters of distillation of the still serve perfectly for
this object. A small quantity of this is added to the cold solution containing the
iron salts, and the two are intimately mixed. All the iron will be precipitated in
the state of sulphide of iron; the liquid clarified by standing or filtration is
evaporated as above said, and is then cooled in the crystallizing vessels of tin, or
lined with tin. The crostale obtained are perfectly pure and white

page_text: •
these high temperatures when the reaction terminates entirely at 450 degrees
*centigrade.
4th. The molten mass should be sheltered from exposure to the air both during
heating and cooling.
5th. The mixture of sulphocyanide of potassium and iron should be very
intimate.
All these conditions may be realized in the following manner:-
The sulphocyanide of potassium melted at 350 degrees centigrade, and the iron
pulverized and sifted are introduced into a rotating vessel containing cast iron
balls, where they are intimately mixed and protected from the humidity of the
air, the vessel, which may be of either sheet or cast iron, being hermetically closed
during the mixing. The mixture is then introduced quickly into crucibles which
are provided with sufficiently tight covers.
These crucibles are placed in a double walled stove or furnace of any suitable
form containing one or several compartments.
The space between the walls is filled with sulphur, and is then heated over a fire
in order to boil the sulphur and to maintain it in a state of lively ebullition.
The upper part of the furnace will be provided with a tube several metres in
length, in which the sulphur which passes off in the state of vapor, condenses, and
returns to the stove or furnace. In this manner the temperature of the interior of the
stove is maintained with great regularity at about 450 degrees centigrade. After
several hours' heating the crucibles or vessels are withdrawn, and their contents are
allowed to cool, sheltered from the air. The contents are then ready to be treated
by any of the known processes to obtain the ferrocyanide of potassium, of which
an amount equal to from 25 to 30 per cent. of the weight of the mixture of sulpho-
cyanide of potassium and iron, according to the proportions employed, will be
obtained.
Instead of mixing the materials before placing them in the stove the mixing may
take place in the apparatus where the fusion is effected. In this case the apparatus
will take the form of a large double crucible, with an opening at the bottom, the
space between the two crucibles being filled with sulphur. This vessel is provided
with a suitable cover, a plug for the bottom, and also a stirrer such as is used in
brickmaking.
The sulphocyanide of potassium is introduced into the vessel, and when it is
sufficiently hot the iron is added, and the stirrer is set to work. When the operation
is terminated the plug is withdrawn from the bottom, and the molten mass is
allowed to run into a pit or receiver, where it is allowed to cool, sheltered from
the air.
It will of course be understood that any other material capable of producing a
regular temperature through its vapor or its fusion may be substituted for the
sulphur, but without any advantage.
A jacket of lead, for instance, the temperature of which is to be regulated by a
pyrometer, will give good results if properly attended to. The sulphur jacket
however possesses this advantage, that it gives by the temperature of its vapor
precisely the heat necessary for the desulphurization of the sulphocyanide by the
iron, and when once properly set to work requires very little attention.
Finally, owing to the relatively low temperature at which the sulphur boils, the
mass being treated cannot be heated above the boiling point of the sulphur, or
about 450 degrees centigrade, and therefore the fear of bringing the mass to a red
heat, which would be both injurious and useless, is avoided.
After what has just been said it will be evident that furnaces such as those used
in the manufacture of glass might be employed concurrently with the sulphur
stove to effect the-transformation of the sulphocyanides into cyanide and sulphide
of iron.
In the accompanying Drawings Figures 1 and 2, Sheet I., show in plan, view,
and elevation the general arrangement of the apparatus for manufacturing sulpho-

page_text: cyanide of ammonia, and Fig. 1 bis shows on an enlarged scale one of the heating
vessels.
A, A', A³, A3, A4, A5, are the heating vessels where the reaction is produced; B
is the force pump for feeding the heating vessels with ammonia and sulphide of
carbon; c is the feed pipe for conveying the liquor to the heating vessels; d is a
pipe for conveying to the still the products of the reaction; E, E', are the still and
its separator for distilling and separating the products of the reaction; F is a coke
cylinder placed above the surface condenser G; H, H', the receivers, into which the
gaseous products of the distillation pass; G¹ is the second condenser placed on the
second receiver H', and F' is the coke cylinder in connection therewith; L, L' is a
gas holder for collecting the gas of distillation.
Fig. 3, Sheet II., shows on an enlarged scale and in sectional elevation the
aluminium still; Fig. 4 is a plan view of the coil contained in the still; and Fig. 5
shows on an enlarged scale and in section the joints between the cover and the
body of the still.
A is the still proper provided with a dismountable cover A¹; a, a', are iron
flanged rings, which are tightened up with india rubber between by means of
bolts.
The edges of the aluminium still and the cover are bent outwards so as to form
flanges all round, which are gripped between the iron rings a, a, as clearly seen at
Fig. 5. The object of this arrangement of joint is to prevent the exposure of any
portion of the iron rings to the attack of the contents of the still, as before referred
to. This joint may also be adopted generally throughout the apparatus; C is the
separator, which is provided with a removable cover C¹; B, B, t, t, represent the
pipe and the sockets through which the products of distillation pass from the still A
to the separator C. The sockets t, t¹, are respectively rivetted to the cover A' of
the still, and to the cover C¹ of the separator C. The joints between the sockets
and the pipes may be made of iron, as above described, or in any other convenient
and suitable manner. The separator C is carried by a short hollow column d, d,
secured to the cover A' of the still. This column must also be made of aluminium,
and it is intended as the means of communication between the still A and its
separator C, whereby any liquid particles carried over in froth may be returned to
the still d², d, is a pipe which forms a continuation of the hollow column d, and
reaches almost to the bottom of the still A; E, E, is the pipe by which the products
of distillation pass off to the surface condenser and its column of coke, shewn in
Figures 1 and 2, Sheet I.; f. f. is the pipe by which the materials to be treated are
introduced into the still A; G, G, is the steam coil for heating the still; g, g¹, are
the sockets or couplings with which the coil is connected, and through which the
steam enters and leaves the coil; H, H, is a liquid gauge connected with the body
of the still A. The metal work of this gauge is of aluminium, and it is provided
with the removable parts h, h, which will allow of the gauge being cleaned so as to
avoid the stoppage of passages by crystals or otherwise; 1, 1, is a thermometer,
which is inserted into a case projecting into the body of the still A ; m is the
emptying cock; N, N, are the supports carrying the apparatus; and P is the base
plate.
Figures 6, 6, Sheet II., show in sectional elevation and plan view another form
of still constructed of enamelled iron. By means of the arrangement of still here
shewn a large amount of heating surface is obtained. A is a reservoir which
communicates through a series of pipes B, B, also forming heating surfaces, with a
second reservoir C placed above it and provided with a liquid gauge; D, D, is a
tube, whereby the products of distillation pass to the separator E, E, which is also
provided with a liquid gauge. This separator serves to dry the products of
distillation; ff. f, is a pipe by which liquids are returned to the lower part A of
the still; G, G, is the tube by which the products of distillation pass off from the
separator; H, H, is an envelope or jacket surrounding the lower portion A of the
still and the tubes B, whereby those portions of the still may be heated by steam;
1, 7, is the emptying pipe, and L the emptying cock of the still,

page_text: Figures 7, 7, Sheet II., represent in elevation partly in section and in plan
view an apparatus for the production of sulphocyanide of calcium. In these
Figures A is the distilling boiler; B, the steam coil for heating the same; C, C, a
basket of perforated sheet iron for receiving the lime; R, an emptying cock; t, a
thermometer; E, a separator similar in character to those already described; F is
the outlet of the separator; G, the pipe for returning the separated liquid portions
to the boiler A; H, a condenser consisting of four tubes surrounded by cold
water; L, a reservoir; m, m, a pipe for conducting the condensed products of
distillation from the condenser H to the bottom of the receiver L; n, a cold
water coil; p, emptying cock; g, liquid gauge.
Figures 8 and 9, Sheet III., show in longitudinal and cross section respectively
one form of apparatus to be used in the manufacture of ferrocyanide. A, A, is a
vessel or stove in which the mixture to be treated is placed; b, b, the door of the
stove; c, c, supports for trays to contain the mixture to be treated; D, D, an
envelope or jacket of sulphur; e, a pipe by which the condensed sulphur vapor
returns to the jacket; F, F, furnace and its accessories; g, g, a screen or shutter
placed outside the door b to prevent loss of heat by radiation.
Fig. 10, Sheet III., shows in sectional elevation another form of apparatus for
effecting the same object. A is a vessel of crucible form open at bottom and
intended to receive the mixture to be heated; B, B, a stirrer which is driven in
any convenient manner; C, a plug carried at one end of a lever c, and intended to.
close the opening at the bottom of the vessel A; D, D, is the sulphur envelope or
jacket contained in a vessel corresponding in form to the vessel A; f, f, tube
whereby the condensed sulphur vapor returns to the jacket D; E, E, furnace and
its accessories.
When it is desired to discharge the contents of the vessel A. into the pit or
receptacle E', where they will cool without being exposed to the action of the
atmosphere, the plug C is withdrawn by raising the opposite end of the lever c
and drawing it back into the dotted position shown in the Figure.
It may
be remarked in conclusion that according to experiments which have
been made sulphocyanides of alkaline metals are desulphurized not only by iron,
but by nearly all other metals under the same conditions as those above described
for the fusion of the sulphocyanide of potassium with iron.
This fact is of great importance with regard to metals, the sulphides of which
are not soluble in cyanide of potassium, seeing that it permits of the direct
production of cyanide of potassium without passing through the ferrocyanide stage.
Thus very satisfactory results have been obtained by melting a mixture of sulpho-
cyanide of potassium and finely divided lead at a temperature of 450 degrees
centigrade.
Having now described the nature of the said Invention for "Improvements in
the Manufacture of Sulphocyanides and Ferrocyanides, and in apparatus to be used
therefor," as communicated to me by my foreign correspondents, and explained the
manner of carrying the same into effect, I wish it to be understood that under the
above in part recited Letters Patent I claim,-
First. The process or processes, substantially as herein shewn and described, for
obtaining the sulphocyanides of ammonia, calcium, and potassium, and the ferro-
cyanide of potassim.
Second. The use of a separating vessel, substantially as and for the purpose
herein shewn and described.
Third. Constructing the still and separating vessel used in the manufacture of
sulphocyanide of ammonia of aluminium or of tin, as and for the purpose herein
described.
Fourth. The arrangement of apparatus for effecting the condensation of
ammoniacal vapours, and for collecting the sulphurretted hydrogen so obtained
preparatory to its passing to a regenerating apparatus, as herein shewn and
described.

page_text: Fifth. The arrangement of apparatus for obtaining sulphocyanide of calcium,
substantially as herein shewn and described.
Sixth. The use of pulverised metallic iron in combination with the sulphocyanide
of potassium, sodium, or other suitable sulphocyanide in the manufacture of ferro-
cyanides of the same bases.
Seventh. The use of a jacket of sulphur or other suitable substance which can
be maintained at an uniform temperature for effecting the fusion of the sulpho-
cyanide of potassium and pulverised iron in the manufacture of ferrocyanide of
potassium, substantially as and for the purpose herein described.
Eighth. The arrangement of apparatus to be used in the manufacture of ferro-
cyanide of potassium, substantially as herein described and shewn with reference
to Figures 8, 9, 10, Sheet III., of the Drawings.
In witness whereof, I, the said Henry Edward Newton, have hereunto set
my hand and seal, the 21st day of September, in the year of our Lord One
thousand eight hundred and eighty one.
DE. NEWTON. (L.S.)