AN IMPROVED MODE OF PREPARING VARIOUS PLANTS TO BE USED IN THE MANUFACTURE OF PAPER
Year: 1860

page_text: LETTERS PATENT to Charles Stevens. Manager of the British & Foreign
Office for Patents, No. 1, Welbeck Street, Cavendish Square, in the.
County of Middlesex, for the Invention of "AN IMPROVED MODE OF
PREPARING VARIOUS PLANTS TO BE USED IN THE MANUFACTURE OF PAPER."-A.
communication from abroad by Eugene Helenus, of Paris, in the Empire.
of France.
Sealed the 9th November 1860, and dated the 6th June 1860.
PROVISIONAL SPECIFICATION left by the said Charles Stevens at the
Office of the Commissioners of Patents, with his Petition, on the
6th June 1860.
I, CHARLES STEVENS, Manager of the British & Foreign Office for Patents,
No. 1, Welbeck Street, Cavendish Square, in the County of Middlesex, do
hereby declare the nature of the said Invention for "AN IMPROVED MODE OF
PREPARING VARIOUS PLANTS TO BE USED IN THE MANUFACTURE OF PAPER," (&
that it has been communicated to me from abroad by Eugene Helenus, of
Paris, in the Empire of France,) to be as follows:-
The present Invention relates to the preparation of the various textile
plants, among which may be named sparte, diss, alpha, alois, the dwarf palm,
stypa tenacessima, & others of similar nature, to be used in the manufacture of
[Price Sd.]

page_text: paper. All these plants possess, as the ruling principle, nearly the same
elements, viz., a gummy resinous matter, glutine, & tannin in considerable
quantities. The plants are treated by a solution at the highest degree of
alkali potash or soda. Soda is preferable to potash, & it is absolutely
necessary that the solution should take place at the highest degree to obtain
success. The quantity of alkali to be employed, if anhydrous, to 100 parts of
the plant varies from 10 to 25 parts. In treating the alpha plant, 20 parts of
anhydrous soda.to 100 parts of the plant may be successfully employed. This
quantity of alkali is necessary for thoroughly removing from the plant all
foreign elements. By these means, after the bruising & washing of the
prepared plant a pulp very easy to bleach is obtained. The alkali does not
effect the tenacity of the fibres, and the chlorides used in bleaching being at a
low degree, act but insensibly.
The pulping is easily effected in beating troughs similar to those employed
in paper manufactories.
As the above mentioned ingredients are expensive, they would appear to be
an obstacle to this mode of preparation, but this objection is at once removed,
as no part of the alkali is lost during its action on the organic matter, but
combines itself with the new bodies produced under its influence. The azote
in the organic matter disengages itself, at any rate in great part, under their
influence, in the form of ammoniac gas. Thus nearly the whole of the soda
employed, supposing soda to be used, is found in the liquids resulting from the
operation, and by evaporation and calcination properly conducted it may be
again employed, as by subjecting the matters to the action of hot water a
solution of carbonate of soda is obtained, which may be easily rendered into
caustic soda by subjecting it to the action of caustic lime, or any other basis
which like lime would take up the carbonic acid of the carbonate of soda, &
so form an insoluble carbonate.
From the above it will be seen that the plant is subjected to a solution of
caustic alkali. The liquid resulting from the operation is properly evaporated
& calcined, the alkali is brought to the state of carbonate alkali, & this
carbonate is decomposed by caustic lime, so as to give a solution of caustic
alkali & of calcined carbonate. The alkali is employed for a new operation,
& the calcined carbonate formed is decomposed by heat; caustic lime results.
which serves in a new decomposition of carbonate alkali resulting from
another boiling.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Stevens, in the Great Seal Patent Office on the
16th November 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
STEVENS, Manager of the British & Foreign Office for Patents, 1B, Welbeck
Street, Cavendish Square, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of June in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles Stevens, Her special licence that I, the said Charles
Stevens, my.executors, administrators, and assigns, or such others, as I, the
said Charles Stevens, my 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 "AN
IMPROVED MODE OF PREPARING VARIOUS PLANTS TO BE USED IN THE MANUFACTURE
OF PAPER," a communication to me from abroad by Eugene Helenus, of Paris,
in the Empire of France, upon the condition (amongst others) that I,
the said Charles Stevens, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Charles Stevens, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement and accompanying Drawings, that is to say:-
The present Invention relates to the preparation of various plants to be used
in the manufacture of paper. These plants, such as the dwarf palm, aloe,
jute, halfa (alfa or sparte) diss, stypa tenacessima, and maize, together with
straw and hay, contain nearly the same clements, that is to say, gummy,
resinous matters. glutine, and a considerable proportion of tannin.
The bleaching of the pulp of the plants has hitherto been extremely difficult
and expensive, and as it was necessary to operate with chlorides at a high
degree, in order to effect a satisfactory bleaching, the tenacity of the pulp was

page_text: impaired. In order to avoid the employment of these chlorides, which are not
only injurious in their action on the pulp, but also very expensive, we treat
the plants by means of agents sufficiently powerful to destroy the various
bodies other than textile matter. The plants are treated by a solution at a
high degree of fixed caustic alkali. (either potash or soda.) or carbonate
alkali. Soda is often preferable to potash, and it is essentially necessary for
the dissolution to take place at a high degree, in order to operate successfully.
The quantity of alkali to be employed (supposing it anhydrous) to 100 parts
of the plant sufficiently dry varies from 10 to 25 parts. When carbonate
alkali only is employed instead of caustic alkali, the operation should be
prolonged, & a greater quantity of reagents should be used, and as the
action of caustic alkali is more powerful it is employed in the preparation of
the more difficult plants. whilst the carbonate alkali is used in preparing
those which are the easiest acted upon.
In treating the halfa plant 20 parts of anhydrous soda may be used with
100 parts of the plant. This quantity of alkali is necessary for thoroughly
removing from the plant all foreign elements. By these means after the
bruising and washing of the boiled plant, a pulp very easy to bleach is
obtained, and the tenacity of the fibres is not affectet by the alkali; and as
the chlorides used in the bleaching are at a low degree, they act but
insensibly.
The pulping is easily effected in beating troughs similar to those usually
employed in paper manufactories, see Pl. 1, Figs. 1, 2, 3, 4, & 5.
The industrial impossibility of this mode of preparation consisted in the high
price of soda or caustic potash, but this is removed when it is explained that
none of the alkali is lost during its action on the organic matter, but combines
itself with the new bodies produced under its influence. The azote of the
organic matter disengages itself in a great measure in the condition of
ammoniac gas. Thus nearly the whole of the soda employed, supposing soda
to be used, is found again in the liquids resulting from the boiling, and
although in various conditions & combinations, by being properly evaporated
and calcined, a mixture of carbonate of soda, a little caustic soda, and a small
quantity of calcined carbonate and pure carbon is obtained. On subjecting
these matters to the action of water (hot preferred) a solution of carbonate of
soda is obtained, which may be easily rendered into caustic soda in solution
by treating it with caustic lime, or any other basis which, like lime, would
take up the carbonic acid of the carbonate of soda, and so form an insoluble
carbonate. Lime may be employed with advantage on account of its low
price, and the facility with which the calcined carbonate repasses into the form

page_text: of caustic me, which allows or its being revived and used in the decom
position of a fresh quantity of -carbonate of soda. Even if the basis employed
were of no value, it would not be advisable to make use of fresh substances at
each operation. as in the decomposition of the carbonate alkali the insoluble
carbonate formed always retains under the form of hydrate, a certain quantity
of alkali, which would otherwise be lost. The caustic solution thus obtained
is employed in the boiling of the plant.
From the above it will be seen that the plant is subjected to a solution of
caustic alkali, and the liquid resulting is properly evaporated and calcined.
The alkali is brought to the state of carbonate alkali, which is decomposed by
caustic lime so as to give a solution of caustic alkali & calcined carbonate.
The alkali is then employed in a new operation, and the calcined carbonate
formed is decomposed by heat. Caustic lime results, which serves in a new
decomposition of carbonate alkali resulting from another boiling. Thus, the
same alkali always returns in the various successive operations; the same lime
always serves in the decomposition of the carbonate alkalis successively formed,
and consequently the sole outlay is for fuel and labour. The apparatuses
employed are constructed so as to aid in the preservation of the alkalis and
lime, and to still further reduce the quantity of fuel and labour required.
These apparatuses we will now proceed to describe-In order that the appa-
ratuses should be of dimensions for convenient working not more than one ton
of the plant should be operated upon at one time. It might even be deemed
desirable to act upon only half that quantity at once, but the apparatus for
about one ton, which we will now describe, appears on the whole preferable to
one of the smaller size. We will take as type of the plants employed the
halfa, the density of which varies from 0'425 to 0'450 according to its degree
of dryness. The form of this plant, and its tendency to lie in a compressed
state, are such that without being subjected to any pressure the space occupied.
by about a ton is equal to 20 cubic feet only. The boiler constructed for
containing a ton of halfa has the form of a right-angled parallelopiped-
(Pl. 2, Fig. 1), 16 fect 8 inches long, by 6 feet 8 inches wide, and 3 feet
4 inches high. It is made of sheet iron about half an inch thick. The angles.
are furnished with iron corner-pieces, and the bottom.is strengthened on the
inside by two T-shaped pieces of iron nearly 3 inches high, comprising
between them equal spaces, and extending the whole length of 16 feet 8 inches.
An iron angle-piece placed at a distance of one half the height extends on the.
outside the entire circumference. The upper edge of the boiler is armed.in a.
similar manner with an angle piece throughout the circumference, and fur-.
nished with bolts screwed in its thickness, and screw-cut to receive nut screws,

page_text: the use of which will be explained. This boiler has a flat cover strengthened
in the same way as the bottom, and it may be further strengthened at the
edges by a flat iron band, in which holes are pierced to correspond with the bolts
fixed to the corner iron, which is placed at the top of the boiler. The boiler
is also strengthened by two interior cramps of T-shaped pieces of iron fixed
transversely in the centre of the length of the boiler, so that the latter is
divided into two compartments each capable of containing about half a ton of
halfa. The cramps may be replaced by a sheet-iron partition of the same
thickness as the sides of the boiler. This partition should be pierced with
holes sufficiently large to allow free passage of the liquid from one compart-
ment into the other. Of the two methods we prefer the T-shaped cramps,
which are united at the bottom of the boiler by means of three other cramps
placed vertically, the screw cut upper extremities of which pass through three
holes placed in the lid at that point. It will be casily perceived that the cover
may be hermetically closed by means of nutscrews adapted to the screw cut bolts
above mentioned, and by three other nutscrews adapted to the vertical arma-
matures which thus hold on the lid. The bolts are placed at intervals of four
inches, and the boiler thus constructed retains the steam very satisfactorily.
A band of lead or india-rubber facilitates the closing of the joint. The cover
is furnished with six rings for receiving the pulley hooks, which serve to raise
the cover when desired. It is also furnished with a steam guage and safety
valve. The boiler is thus a digester, the construction and mode of closing of
which may be varied. On the side of the boiler, and as near as possible to
the cover a tube of rather more than three inches diameter is adapted to
allow the escape of the ammonia gas produced during the boiling. This tube
conducts the gas into a receptacle containing chlorhydric acid, where it passes
into the state of chlorhydrate of ammonia. The receptacle is made of lead,
and provided with a safety valve, which opens under a lower pressure than
that resting on the cover of the boiler (Pl. 2, Fig. 2). The bottom of the
boiler is furnished with an emptying tube of rather more than three inches
diameter, fixed by means of rivets, and passing on the inside as far as the
upper level of the T-shaped irons, which serve as armatures, in order that
there should always remain a certain quantity of liquid when the boiler is
emptied. The mouth of the emptying tube is furnished with an iron grating
to prevent the obstruction of the tube by solid matters being drawn into it.
Two iron frames or cages of parallelopiped form made of angle iron, may be
introduced & withdrawn at will in the boiler. They are placed on the
T-shaped irons, serving as armatures to the bottom, and are connected by
round bars of iron, and furnished with a trellis of iron wire. In these cages

page_text: the first matters intended to be prepared are placed. The boiler is heated by a
furnace situated directly beneath it, or by means of a winding tube in which
steam is introduced. When the cover of the boiler is raised and suspended
at a height of 8 feet 4 inches (Pl. 2, Fig. 1), the boiler being empty, on
turning the cock a solution of caustic alkali flows into the boiler in sufficient
quantity to give the desired amount of anhydrous alkali. Whilst the liquid is
thus running into the boiler the matters to be operated upon are introduced
in the following manner-The two iron cages above mentioned, which are
large enough to contain the whole of the matters, are brought on trucks
running on rails from the storehouse where they are loaded to the boiler. A
car furnished with a windlass, and running on rails placed on the lateral walls
which enclose the boiler longitudinally, is conducted along these rails as far as
above one of the cages filled with the plant. On working the windlass four
hooks descend and seize the cage by means of four handles placed at the angles;
it is then raised loaded until its lower part is a little above the upper level of
the boiler. The cage is maintained in this position by catches, and is then
moved until it is suspended directly over the compartment into which it is to
be introduced, when after uncatching it, it is lowered by a movement similar
to the preceding one. The position to be occupied by the car on which the
cage is placed is fixed by wedges moving round a revolving shaft. The same
operation is repeated with the second cage. During the above operations the
boiler continues to receive the warm alkaline liquid. Another cock is then
turned on, giving hot water until the plant is covered. The cover is then
lowered by the same means by which it was raised; the whole of the nutscrews
serving to close it are arranged; a slow fire is kept burning until the desired
degree of pressure is attained, and this pressure is carefully kept up. Four
hours and a half after commencing operations the boiling is completed. The
fire is extinguished half an hour in advance, and the pressure is allowed to
descend by passing steam slowly into the gas-condensing apparatus. Finally,
the other valve is opened, and two men withdraw the nutscrews retaining the
cover by means of keys, the cover being raised by pullies. This operation is
rapidly executed when the men are accustomed to it. Each nutscrew is
placed opposite the corresponding bolt on the cover of the boiler; and in
order that they should not become disarranged, they are hooked to small iron
rods about an inch in height, which are fixed on the lid.
The cages are emptied in the same way as they are loaded; but when one
of them is raised out of the boiler the boiled plant is washed by playing hot
water on it with a tube of gutta percha or other material, furnished with a
cock. From the moment when the steam is let off to equalize the interior to

page_text: the exterior pressure, the emptying cock is turned on and the pumps are put
in motion, passing the liquid into a second boiler, of which we will shortly
speak. The pumps continue to work until no more of the liquid remains but
a small quantity, which the arrangement of the emptying pipe does not allow
to be drawn off.
The quantity of liquid necessary for entirely covering a ton of halfa is
rather more than 13-cubic feet, but this must vary according to the density
and closeness of the plant.
We employ rather more than 3 cubic feet of water for the washing; thus
by means of the pumps 16 feet 8 inches (cubic) of liquid should be passed
from the first into the second boiler. If the first boiler could support a pres-
sure rather superior to the second one, it will be easily perceived that the
pumps might be dispensed with. In order to accomplish this it would be
necessary to construct the first boiler of greater thickness, and strengthen
it in a different manner. We, however, think the use of pumps is to be
preferred.
The 2nd boiler has a double object, viz., the partial evaporation of the
liquors resulting from the boiling, and the employment of the steam resulting
from the evaporation. The boiling occupies 6 hours, and therefore 16 feet
8 inches (cubic) of water is evaporated in that time. Experience shows that
this quantity of water, when reduced to 3 feet 4 inches (cubic), begins to take
a consistency, so that it is not desirable to continue the evaporation in this
boiler. We therefore restrict ourselves to evaporating about 13 cubic feet in
6 hours, which gives a force equal to that of 25 horses.
Before causing the liquid to pass into the 2nd boiler, 3 feet 4 inches (cubic)
of the concentrated liquid is introduced by the pressure of the steam into a flat
boiler or basin by means of a tube with a cock, where it is boiled and concen-
trated by allowing the steam to escape. The liquid has now become still
thicker, and is passed into a 4th boiler or basin, from whence it is con-
ducted by a cast-iron tube furnished with a valve or cock into a reverberatory
furnace on which it is placed. In this furnace the evaporation is terminated,
and a blackish granular substance remains, which consists of a mixture of car-
bonate, alkali, and carbonised matters. The process which this substance
undergoes will be hereafter described.
The 2nd boiler above mentioned only requiring to be fed intermittently
consists of two parts, viz., the boiler proper, and the receptacle or reservoir for
receiving the whole of the water to be evaporated. It is composed of a tubular
boiler, placed at the lower part, and capable of containing the water resulting
from one boiling, which in the case above described consists of 16 feet 8 inches

page_text: (cubic). The capacity of this species of reservoir is here 26 feet 8 inches
(cubic). The communicating tubes of the reservoir and tubular boiler are
six in number, and of a large diameter. The whole is surmounted by a steam
dome.
The tubes of the tubular boiler should be of iron, as most constructors find a
difficulty in rendering the boiler steam-tight. It is nearly as economical to
make them of copper, but in this case they must be plated, to counteract the
destructive effect of the alkalis.
The cylindrical tubular boiler has at its lower part a space without tubes, in
which lower part is placed the emptying tube, arranged, as already stated, to
pass 3 feet 4 inches (cubic) of liquid into the 3rd boiler before introducing
for the feeding the 16 feet 8 inches (cubic) of liquid coming from the 1st
boiler. It is unnecessary to enter into the details of the construction of the
furnace or fire-box, it being the same as that employed in locomotive engines.
A boiler with tubes may be employed if only the above-mentioned part be
heated, and being easy of construction, is often to be preferred.
As the feeding is intermittent the level of the liquid should be ascertained
every moment, in order always to concentrate the liquors at nearly the same
degree before passing them into the 3rd boiler. For this purpose an indicating
float is placed as follows (Pl. 2, Fig. 3):-The difference between the extreme
levels being represented by h, we place above the point of attachment K of
the suspending bar of the float and at the distance indicated K, which is at
least equal to h, a small pulley, on which a chain passes, and of such a kind
that the vertical prolongation of the bar is tangent to this pulley. By means
of a returning pulley, placed according to circumstances, the other extremity of
the chain, to which is suspended a counterweight, is brought in sight of the
operator, and a needle indicates on a rule placed and graduated for the pur-
In order that this appa-
pose the momentary level of the liquid of the boiler.
ratus should work correctly it is sufficient that the float should be rather larger
to cause the difference in the weights to be manifested to a perceptible extent.
These floats must be rendered impregnable to the action of the alkalis by first
coppering and then plating them by galvanism.
The third & fourth boilers or basins have no precise form or dimensions, but
vary according to circumstances.
A beneficial result is obtained by preparing the bottom, which alone should
be heated, with corrugated sheet iron, like that employed for roofing. The sur-
face exposed to the heat is thus increased by about one-third, without enlarging
the. dimensions of the bottom, which is also strengthened by this shape.
The boiler No. 3 is situated below the boiler No. 4, in which, as already

page_text: stated, a part of the liquid is made to pass, when sufficiently concentrated, by
means of a tube with valve. The arrangement of placing the boilers above
each other may be dispensed with by emptying by means of a pump or siphon.
This, however, must depend upon the conveniences for placing the apparatus
and other circumstances.
The reverberatory furnace is placed below the boiler No. 4, which supplies
it with the viscous matters to be dried. The body of the furnace should be
rather long, and the bottom is covered with carbonate of soda well dried and
pounded. The heated gases proceeding from this furnace pass under the
boilers Nos. 3 & 4, and are thus employed in the evaporation in conjunction
with those resulting from a special furnace, when it may be necessary. It is
desirable to have two furnaces joined, in order that operations may not be
interrupted during repairs.
The operation to be performed in this furnace consists in a mixing, which
must be effected with great care to prevent too many matters being carried off
by the current of gas. When the workmen are not. very skilful it may be
found advantageous to throw into the furnace on the still pulpy matter a
certain quantity of lime, or better still of carbonate of lime, but free from all
silicious matters. A gelatinous substance is then formed more compact,
which swells out much less and consequently almost entirely avoids any loss.
The matter resulting from the calcination thus accomplished is more compact
and lends itself more readily to the operation of washing although leaving a
greater residuum.
It now remains to describe the apparatuses employed in the revivification of
the caustic alkalis.
The matter coming from the reverberatory furnace is ground between
cylinders or otherwise, during which operation the matter should be slightly
damped to prevent the rise of particles which might be injurious to the
health of the workmen. In order to extract from this matter the soluble
parts, which consist, as already stated, of carbonate of soda and a little
caustic soda, we employ the apparatus in ordinary use in drug manu-
facturies, but any other method may be adopted. The washing is un-
necessary when the operation in the reverberatory furnace is conducted
with sufficient care without adding inert matter, as the produce consists of
carbonate of soda nearly pure more or less blackened with carbon, and by
placing it in a basin these elements separate, but this operation is difficult
and may cause a serious loss of carbonate of soda. The apparatus consists
of rectangular receptacles of sheet iron arranged in a gradual slope, one
beneath the other, see Pl. III., Fig. 1, showing 10 of these receptacles

page_text: being the number required in an apparatus for preparing one ton of the
plant in 6 hours when chalk is added to the reverberatory furnace. A
larger or smaller quantity however may be employed according to the degree
of exhaustion it is desired the residuum should attain. The upper edge
of the first receptacle A is level with a cast-iron plate, slightly inclining
towards the receptacle, and on this plate the baskets of which we are about
to speak are allowed to drain on coming out of the receptacle A, which com-
municates with the receptacle B, as each communicates with the next one
by means of a tube adapted at a distance of about 6 inches from the bottom,
pouring the liquid to the level of the edges of the next receptacle. The
last one B, empties itself into a basin capable of holding 330 gallons of
liquid provided with a graduated scale; the zero of which commences at
the upper part, and the use of which we will describe further on.
In the case taken for example the dimensions of the receptacles A & B
to B are 28 inches in depth by 32 in height; and those of the basin above-
mentioned 5 feet long by 4 feet 4 inches wide and three feet high; these dimen-
sions however may be varied according as desired. The manner in which
this apparatus operates is as follows:-On leaving the reverberatory furnace
after being ground into small grains (avoiding as far as possible the formation
of dust or powder) the matters in sufficient quantities to contain about 8 cwt.
of carbonate of soda are placed in sheet iron baskets perforated with small holes.
The receptacles being filled with hot water, four baskets, each containing
about 45 lbs., are placed in the receptacle B. After remaining there 35
minutes they are removed to the basin immediately above, and their place
taken by four more baskets, and so on until the first four baskets have
From thence they are
arrived at the cast-iron plate where they are drained.
emptied on to an inclined plane conducting the waste substance to the cars, which
convey it to the reverberatory furnace where it is employed as inert matter
to prevent swelling. When the operation at the reverberatory furnace is
conducted without any addition of inert matter, the waste substance gives but
one per cent. of residuum composed of pure carbon and calcined carbonate
without any trace of carbonate of soda if the washing has been properly per-
formed. In this case the waste substance is thrown aside, and after a certain
time may be burned without difficulty, and by washing a little more car-
bonate of soda may be obtained, but when the washing has been properly
conducted this is unnecessary. The baskets of the receptacle B³, having
arrived at the cast-iron plate, a current of hot water (from 45° to 70° Re.).
is introduced into the receptacle A, regulated so as to flow in six hours

page_text: into the settling basin filling it up to the zero of the scale or indicator
above mentioned. To obtain this result with facility the cock for introducing
the water into the upper receptacle A is in communication with another
cock, which allows the liquid in the receptacle B8 to pass into the settling
basin so that by closing the latter the first-mentioned one closes at the same
time, and vice versa. This connection however must not be fixed, but so that
when necessary the cocks may be used separately. Hot water may be easily
obtained without expense by utilising the escaping steam. The basin thus
contains a solution of carbonate of soda, which the overseer tests with an
alkalimeter. This test need not be very exact, and is checked or controlled
by another, as will be explained. It is made with a small bottle graduated
in a particular manner, the figures on which indicate the quantity of liquid
to be introduced into the decomposing tub or vat. They are repeated on the
scale of the settling basin, so that if the figure on the testing tube is 12, the
overseer opens to the figure 12 of the scale of the vat. A black board is
placed at the side of the settling basin bearing on a column numbers cor-
responding with those on the testing tube with holes opposite. A peg is
introduced in a hole corresponding with the figure on the testing tube,
and when once introduced this peg can only be withdrawn by opening a padlock.
The liquid is passed into the decomposing tub in which hot water is intro-
duced until the level has risen to a height indicated on a scale also placed
in this tub. During these operations the quantity of steam necessary for
keeping up the hot water of the apparatus is let off by means of cocks,
at the decomposing tub the liquid is carried to boiling point, which is done
without difficulty. The work of decomposing by caustic lime is then begun.
We employ two vats in order to have time to remove the calcined carbonate
formed, which gives a deposit to be used in a new operation. Thus not
more than one operation in 12 hours takes place in one vat. Above the two
decomposing vats are arranged pieces of timber bearing rails on which
moves a windlass having a kind of reservoir in which is prepared the lime-
white necessary for the decomposing. About 14 cwt. 1 qr. of good caustic
lime is employed to make the decomposition of carbonate of soda for pre-
paring a ton of halfa. The reservoir should be capable of containing about
264 gallons in order that the lime-white should not be too thick; but to
facilitate the operation the reservoir may be only half that size and two
successive quantities of lime-white be made for the decomposition of the
contents of a single vat.
The reservoir is a kind of boiler of cast iron, 4 feet 6 inches in diameter,

page_text: having a spherical form; the bottom is furnished with a valve, Pl. III.,
Fig. 2, which acts as a cock, and the lime-white is allowed to flow as slowly
as desired. The object of this valve is to avoid all roughness or hollowness in
the boiler, so as to be able to make the lime-white with a sort of wooden
stamper, as in a mortar: small tubes protect the worm of the screw from the
liquid during the running off.
When the operator considers the decomposition accomplished he completes
the filling of the vat, the level of which is raised by the addition of lime-white
with a quantity of water sufficient to raise the level to the zero of the
graduated scale. A densimeter, having figures which correspond with the
divisions of the scale placed in the vat, is then plunged into the liquid. The
number found is written, the same as the alkalimetrical test, on a board
placed close by. This figure indicates to what point of the scale the liquid in
the decomposing vat is to be allowed to descend when the alkali is made to
enter the preparing vat.
It will be easily understood that the two tests of which we have just spoken
control each other; for if they are exact, and the decomposition of the
carbonate alkali is complete, any number of the alkalimeter has its corre-
sponding number marked on the densimeter, as the quantity of liquid is
the same.
A table of these corresponding numbers remains in the desk of the director
of the manufactory, and when, after the day's operations, the slates or black
boards are raised, and the small pegs removed, by glancing on the board of the
corresponding numbers, he is enabled to see if the operation has been properly
performed. The decomposition in the boiler being terminated the lime-white
vat is passed above the second one, where the operation is to be continued.
After introducing the alkaline liquid in the preparing boiler a certain quantity
still remains in the decomposing vat. This quantity will always be the same
if the test of the carbonate alkali has been well performed, varying from 15
to 20 above the deposit of the calcined carbonate. To carry off the deposit
this liquid is made to pass more or less disturbed into the empty vat by means
of a hand pump. The deposit is soon visible, but is generally too damp to be
removed. Caustic lime is then introduced, which absorbs the greater part of
the water, and the mass soon becomes sufficiently thick to be casily removed.
This vat when emptied is ready to receive the liquid remaining at the bottom
of the other vat, in which an operation has just been performed.
The calcined carbonate obtained is placed in a reverberatory or other
furnace, where it passes into the condition of caustic lime. When a rever-

page_text: beratory furnace is employed it is charged with a hopper, & water is thrown
at intervals on the matter in order to facilitate the disengaging of the carbonic
gas by the presence of steam. The heat lost by this furnace passes under the
boilers Nos. 3 & 4, where it serves in the evaporation. The dimensions of
the decomposing boilers are calculated so as to contain "the liquid necessary
for a good decomposition, together with the lime-white afterwards added. The.
capacity of each of them cannot be less than about. 990 gallons. By giving
them a diameter of 7 feet 8 inches, and a height of 5 feet, the object is
attained. In this case the calcarious deposit after the decomposition. is/about
10 inches in height. A circular form is almost indispensable in order to
operate easily the mixing of the matters. The emptying of these vats into
the preparing boiler is done by means of a cock placed about 14 inches from
the bottom, or by the aid of a siphon. In the latter case the rod of the siphon
which is introduced into the vat is graduated from its lower extremity, and is
plunged into the liquid to the level at which this liquid should lower. It is,
therefore, moveable in a vertical direction. The flowing naturally ceases 'when
enough liquid is passed into the preparing boiler. This alkaline solution
always contains a certain quantity of lime, dissolved by means of the surplus.
water and the presence of soda. This lime passes into the boiling vat, where
it is transformed into carbonate, but it does not attach itself to the boiler, and
is carried into the midst of the organic matters. The presence of calcined
carbonate in the residuum of the calcination is thus explained.
Having thus described the nature of my Invention, and the manner in
which the same is or may be carried into effect, what I claim and desire to
secure by Letters Patent is,-
3
1st, preparation of the plants in a solution at a high degree of a fixed alkali,
potash, or soda. By a solution at a high degree is meant a quantity of fixed.
alkali or carbonate alkali so as to be impossible to lose the residuum of the
boiling. The precise quantity of alkali to be employed cannot be indicated,
aš it varies with the state of maturity of the plant and the different species
of plants subjected to the preparation; but, for example, we will state the
quantity as 20 parts of anhydrous soda to 100 parts of halfa when arrived
at complete maturity.
2nd, revivification of the fixed alkali employed by evaporation and combustion
of the residuum resulting from the boiling and pulping or cleansing of the pre-
pared matters, the extraction of the alkaline matters of the produce of this
evaporation and, calcination being effected in the usual way.
3rd, revivification of the lime or other basis, such as boryte strontiane,

page_text: capable of forming with the carbonic acid of the carbonate alkali an insoluble
carbonate to be again employed, in order not to lose the alkali which they may
hold in combination.
4th, employment of the steam resulting from the evaporation of the liquids
as motive power in the establishment.
With respect to the different apparatuses and modes of operation above
described, we wish it to be understood that they may be varied or replaced by
others, the above description only indicating those which we consider preferable,
and which we have described in order to render the mode of preparing the
plants more easily understood.
In witness whereof, I, the said Charles Stevens, have hereunto set
my hand and seal, this Sixteenth day of November, in the year of our
Lord One thousand eight hundred and sixty.
CHARLES STEVENS." (L.S.)