IMPROVEMENTS IN THE MANUFACTURE OF CARBONATES OF SODA BY THE AMMONIACAL PROCESS
Year: 1876

page_text: LETTERS PATENT to Ernest Solvay, of Brussels, in the Kingdom of Belgium,
Manufacturer, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF CARBONATES OF SODA BY THE AMMONIACAL PROCESS."
Sealed the 14th July 1876, and dated the 5th May 1876.
PROVISIONAL SPECIFICATION left by the said Ernest Solvay at the Office
of the Commissioners of Patents on the 5th May 1876.
ERNEST SOLVAY, of Brussels, in the Kingdom of Belgium, Manufacturer. "IM-
PROVEMENTS IN THE MANUFACTURE OF CARBONATES OF SODA BY THE AMMONIACAL
PROCESS."
My Invention relates to the manufacture of carbonates of soda by the process
generally known as the ammoniacal process, for which Letters Patent were granted
to me bearing date the 11th of December 1863, No. 3131, and the 18th of May
1872, No. 1525, and which process as further improved by inc is described in a
Provisional Specification filed by me in the Great Seal Patent Office on the 8th
day of March 1876, No. 999.
My present Invention having reference to different processes and apparatus used
in the said manufacture, I will proceed to describe each of the improvements
separately in relation to the part of the manufacture to which it applies. The
manufacture of carbonates of soda by the ammoniacal process is now well known,
having been described in the Specification of iny said Patent of 1803.
The first part of my Invention relates to the distillation of ammonia, and consists
of the two apparatus herein-after described for distilling the aminoniacal liquor
which has been separated from the bicarbonate of soda just formed. The said
apparatus accomplishing practically the conditions required for the continuous dis-
tillation of large quantities of such ammoniacal liquor.
The first of the said apparatus consists of a distilling column for distilling with-
out lime, and of a series of distilling boilers for distilling with lime, into which
boilers the liquid passes from the distilling column. The said boilers, of which there
may be four or any suitable number, communicate one with the other by means of
a distributor such as is used in gas or other works.

page_text: The said distributor allows one or more boilers to be isolated successively for the
purpose of emptying, cleansing, or refilling it or them without intercepting the
manufacture. Those boilers which are not isolated are in the circuit. The steam
required for the distillation, and which may be the exhaust steam from the motive
engines enters the distributor, and passes through the series of boilers in the circuit, a
and then with the ammonia that has been disengaged passes into the distilling
column, the upper compartment of which column acts as a refrigerator, being pro-
vided with a refrigerating coil of pipes, into which the liquid to be distilled is
introduced, and in which it begins to get heated, condensing at the same the vapour
of water contained in the gases evolved. The liquid follows exactly an opposite
course to the steam, so that the residuum passes out of the boiler at the part at
which the steam first entered. I regulate the introduction of the liquid by means of
a regulating apparatus, consisting of a float in a reservoir containing a certain
quantity of water. The gases emitted in the distilling process communicate more
or less heat to the said water and cause the said float to fall or rise, and the said
float acting on a valve or cock thus regulates the admission of liquid into the coil
of pipes herein-before described according as it is required for the operation. The
said float may also be applied for regulating the admission of steam into the boilers.
After descending to the bottom of the distilling column the liquid is made to pass
into the boiler which has just been charged with lime, the said lime may be slaked
previously; but in order to utilize the beat produced in the slaking process I prefer
to introduce the said lime in blocks or pieces as it leaves the lime kiln. For this
purpose I use a basket or open work compartment which retains the unburnt parts
which may be afterwards removed. The lime in the said basket is acted upon
successively by the rising liquid in the boiler, and the steam given off by the heat
produced is used in the distilling column. The number of compartments in the
distilling column may be varied. To improve their effect I provide them with false
bottoms, such as are described in the Specification of my Patent of 1872, in
reference to my absorbing columns.
The second of the said apparatus is a modification of the first just described.
My said second apparatus consisting of a single distilling column somewhat similar
to the distilling column herein-before described, but provided with a larger number
of compartments, which compartments are numerous enough and are arranged so as
to replace the boilers, and are provided with a separate apparatus for the action of
the lime.
The upper portion of the said distilling column is similar to the distilling column
herein-before described, the lower portion of the said distilling column may be of
similar construction to the absorbing column described in the Specification of my
Patent of 1872, in which column liquid charged with solid matter in suspension is
treated.
Between the said upper and lower portions, and on the side of the said distilling
column, I arrange two or more than two cylindrical reservoirs each provided with a
conical grated false bottom or basket containing quicklime. The ammoniacal liquid
is made to enter the said cylindrical reservoirs so as to immerge only part of the
lime contained therein, and having dissolved the required quantity of the said lime
it re-enters the column. The lower part of the said lime having been dissolved, the
remainder gives way and sinks down successively so that all the lime passes
successively into the column in a state of solution. The impurities are retained in
the basket, and are removed therefrom when the said reservoir is isolated from the
column, to be recharged with lime, which is effected when another of the cylindrical
reservoirs is put into communication with the column by means of cocks, or taps, or
valves. The ammoniacal gases disengaged in the said apparatus pass into the
column through a suitable pipe provided with a cock or tap, which so regulates the
outlet of the said ammoniacal gases that if the disengagement of the said gases be too
great the said gases will be prevented from escaping all at once, and will force back
the liquid, and the admission of liquid and its consequent action upon the line will

page_text: thus be suspended till the said gases escape and enable the liquid again to enter
the apparatus.
Whatever be the distilling apparatus employed I facilitate its action by forming
a vacuum over the liquid which is to receive the distilled ammoniacal gases. A
water piston pump is very suitable for the purpose, but in any case lixiviating
receivers must be placed between the vacuum pump and the distilling apparatus in
order that no ammonia may be lost.
My Invention relates, secondly, to the preparation of the ammoniacal brine, and is
particularly applicable to cases in which natural brines are to be treated, common
salt if used should be previously dissolved. This part of my Invention is not
applicable when the salt is dissolved in receivers which already contain the ammonia
required for the manufacture.
The most simple process is based upon the following important fact, viz., that if
lime be added to brine containing salts of magnesia, either alone or accompanied
by salts of lime, the said salts of magnesia are precipitated, and if carbonate of
ammonia be added to the salts of lime the said salts of lime are precipitated much
more easily than the salts of magnesia. I therefore add lime to the impuro brine
and agitate the mixture for some time, then when the magnesia and the lime in
suspension are precipitated I add thereto a suitable quantity of carbonate of
ammonia, which quantity need not be more than chemically equivalent to the
quantity of the salts of lime dissolved.
The said process is effected preferably by operating in two receivers, that is to
say, decanting into one of the said receivers the liquid after adding lime thereto,
and in the other receiver adding carbonate of ammonia to the decanted liquid, the
required carbonate of ammonia is to be found in various lixiviating apparatus which
retain the ammonia escaping from the operations of the manufacture. The said
carbonate of ammonia must not contain more than one equivalent of carbonic
acid.
If it be desired to avoid the addition of lime much more ammonia would have to
be used, and the process would become very costly unless recourse were had to
the means I have invented, and which consists in purifying the brine during the
course of the manufacture and at the time that the brine is being saturated with
ammonia.
The means of operating are as follows:-I provide a receiver, which I call a
dissolver, and which is made to communicate with each of two or more reservoirs
by means of two pipes, one near the bottom of the said apparatus the other near
the top, so that the liquid may be made to circulate through one of the said
reservoirs and the said dissolver. The dissolver is provided with a false bottom,
below which the ammoniacal gas is introduced, and with a coil of pipes to regulate
the temperature of the liquid.
For the purpose of saturating the liquid contained in one of the reservoirs the
said liquid is made to pass several times through the dissolver, such circulation
being produced by any suitable propeller. When the level in the reservoir is
ascertained to have attained the required height the communication between the
reservoir containing the saturated and dosed liquid is shut off and the same
operation is renewed with another reservoir.
The ammoniacal liquid being no longer in motion the different precipitated salts
of lime and magnesia,which viciated it are deposited. A first deposit may be
allowed to take place in the reservoir, or all the liquid may at once be made to pass
into a decanter in which it is decanted. In order that it should be more com-
pletely purified the said liquid is then filtered through a closely woven cloth, being
forced through the said cloth by a pressure of several atinospheres. By giving to
the said cloth the form of a sack and fitting it on to a perforated metal cylinder
t will have sufficient strength for the purpose. When the said sack is full of
leposit it is changed for another. The liquid now has to be cooled, which is
ffected by causing it to pass through a series of concentric pipes, the said
A 2

page_text: liquid passing through the inner pipes and the refrigerating water through the
outer ones, or vice versa, and in opposite directions.
The dosing of the ammonia into the brine may also be effected by self-acting
apparatus, and in carrying out this part of the Invention I utilize not the difference
in the density of the liquid produced by the addition thereto of ammonia as in the
apparatus described in the Specification of my said Letters Patent of 1863, but
the difference in the bulk or volume of the said liquid. This removes the causes
of error which the presence of more or less carbonic acid would give rise to if the
difference of density of the liquid were employed. And I have invented the means
of utilizing the regular increase of the volume or bulk of natural brine produced
by each dose of ammonia it absorbs. I put the dissolver into communication with
two reservoirs, one of which serves for measuring the brine and introducing it into
the said dissolver, whilst the other draws out therefrom a corresponding quantity
of animoniacal brine of the required richness. Thus I regularly introduce into the
dissolver given quantities of natural brine and draw off from the said dissolver
corresponding quantities of ammoniacal brine when the liquid has become sufficiently
rich. For this purpose the two reservoirs above mentioned are provided with a
double lever motion actuated by a float in one of the said reservoirs. The said
float, which when the ammoniacal brine in the reservoir has reached the required
level, acts upon a valve or cock so as to cause it to evacuate the ammoniacal brine,
and as soon as this is evacuated the said float having descended acts upon another
valve or cock in the other reservoir so as to introduce into the dissolver the required
amount of natural brine. I have found that when the extraneous salts contained
in brine are removed the said brine (if the quantity of the said extraneous salts be
considerable) is no longer sufficiently saturated as the said salts took up the place
which should be occupied by the chloride of sodium. To prevent this great incon-
venience I add salt to the brine so as to restore the saturation. The said addition
of salt is effected either after or during the purifying operation, and in the latter
case I utilize the increased dissolving capacity of the liquid produced by its
elevated temperature.
My Invention relates, thirdly, to the addition of natural brine and salt in the
absorbing apparatus or column in which the absorption of carbonic acid is effected,
and it consists in introducing natural brine near the top of the said apparatus so
as to better retain the ammonia which the motion of the gases tends to drive out.
I introduce salt either in suspension or separately into the said brine at about the
same part of the apparatus. The said salt which is insoluble in saturated brine
now becomes soluble in the said apparatus, thanks to the presence of carbonic acid,
and thus the yield of bicarbonate of soda is increased.
My Invention relates, fourthly, to the dissolution of hydrochlorate of ammonia,
and consists in the process herein-after described for dissolving and separating from
the bicarbonate the crystals of hydrochlorate of ammonia, which may be formed
in the reaction apparatus or absorbing column when salt is added as herein-before
described, the low temperature maintained in the said apparatus or absorbing
column being favourable to the production of such crystals.
For this purpose I take advantage of the circumstance that the action of heat
increases the solubility of hydrochlorate of ammonia much more speedily than the
solubility of bicarbonate of sodn.
I apply heat either at the bottom of the reaction apparatus or preferably at that
part where the liquid passes out of the said apparatus, or else I obtain the same
result by heating the liquid used for the lixiviation of the bicarbonate in the
filter.
The crystals of hydrochlorate are thus dissolved without any remarkable loss of
bicarbonate of soda, and without interfering with the low temperature required for
the reaction.
My Invention relates, fifthly, to the filtration of the liquid containing the bicar
bonate of soda consists of a continuous filter herein-after described.

page_text: The
The said filter consists of a circular horizontal reservoir capable of motion round
a central axis, the said reservoir is divided into a certain number of compartments
forming sectors of the apparatus. The bottom of each of the said compartments
is composed of wire gauze, or of a perforated plate covered over with a filtering
cloth or material. The said reservoir is placed upon a plate in which are holes
under each of the said compartments. The said plate is supported by the upper
plate or cover of a chest of similar section, and having in it the same number
of corresponding holes or apertures less one. The said reservoir and the said
plate rotate upon their axis above the said chest, which is stationary.
liquid poured into one of the compartments of the said reservoir is caused to
filter through into the said chest by the action of a vacuum created and main-
tained in the said chest by a suitable air pump. A slow and intermittent
rotatory motion being communicated to the upper part of the apparatus, the
said compartment just referred to moves successively forwards, and when the
bicarbonate is sufficiently purified the said compartment is brought successively
before several reservoirs, the first of which reservoirs contains liquid which has
already been used for a previous lixiviation, and the last of the said reservoirs
contains pure water.
The bicarbonate in the compartment above mentioned is successively lixiviated
by each of the said liquids and by the said water. When tife operations are
terminated the said compartment and the reservoir will have completed one revo-
lution, and the said compartment will be over that part of the top of the chest
above mentioned where there is no aperture or hole.
The bicarbonate is then removed and the said compartment begins another
revolution, and receives a further quantity of the liquid to be filtered. Tho
bicarbonate in each compartment thus passes through all the different stages of
the operation, and all the said compartments are charged and discharged at the
same place and at the same point of the revolution of the reservoir, and the different
compartments respectively contain liquid at the same time in the different degrees
of the operation.
The bottom chest herein-before described is divided into compartments for the
purposes of the operation. In a first compartment is collected the filtered liquid,
which is to be sent to the apparatus for the distillation of ammonia, and of the water
which has already served for several lixiviations. In another of the said com-
partments is collected the water which having already been used for the first
lixiviations has again to pass upon the bicarbonate. The said water by the action
of the vacuum is drawn up into suitable reservoirs from which it is conducted
to upon the bicarbonate to be lixiviated before being sent to the distilling
apparatus.
The air pump is arranged so as not only to draw up the liquid placed upon the
filter, but also to elevate the liquid which is again to be used in the reservoirs.
The said reservoirs are disposed in pairs so that while one is being emptied.
the other is being filled with the same liquid. The distributor is arranged so
that the liquid poured upon the whole extent of each compartment, and the
opening and closing of the reservoirs may be regulated automatically by means
of floats.
The essence of the said apparatus is its being continuous, its form, arrangement,
the number of its compartments may be varied without interfering with the simul-
taneous working of the different parts of the operation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ernest Solvay in the Great Seal Patent Office on the 3rd November
1876.
ERNEST SOLVAY, of Brussels, in the Kingdom of Belgium, Manufacturer. "IM-
PROVEMENTS IN THE MANUFACTURE OF CARBONATES OF SODA BY THE AMMONIACAL
PROCESS."
My Invention relates to the manufacture of carbonates of soda by the process
generally known as the ammoniacal process, for which Letters Patent were granted
to me dated the 11th of December 1863, No. 3131, and the 18th of May 1872,
No. 1525.
My present Invention having reference to different processes and apparatus used
in the said manufacture, I will proceed to describe each of the improvements sepa-
rately in relation to the part of the manufacture to which it applies. The manu-
facture of carbonate of soda by the ammoniacal process is now well known, having
been described in the Specification of my said Letters Patent of 1863.
The first part of my Invention relates to the distillation of ammonia, and consists
of the two apparatus herein-after described for distilling the ammonia contained in
the ammoniacal liquor which has been separated from the bicarbonate of soda just
formed. The said distilling apparatus practically accomplish the conditions required,
which arc-
1. To treat continuously and with facility large quantities of ammoniacal liquid.
2. To first remove from the ammoniacal liquid all the carbonated ammonia it
contains.
3. To use as little lime as possible.
4. To utilise as well as possible the heat, and especially the heat produced by the
slaking of the lime, and also the exhaust steam from the driving engines.
5. To allow of the lime being used as it comes from the lime kiln, with the
unburnt parts and impurities which accompany it.
G. To prevent a too violent and dangerous disengagement of gas which would
take place if the ammoniacal liquid were caused to act upon the lime too suddenly.
The first arrangement of apparatus is represented in Figs. 1, 2, and 3 of the
accompanying Drawings. Fig. 1 being a vertical section, Fig. 2 a plan partly in
section, and Fig. 3 a plan of one of the false bottoms of the distilling column.
The distilling apparatus consists of a distilling column A for distilling without
lime, and of distilling boilers B, B1, B2, B3, for distilling with lime, the liquid
passes into the said boilers from the distilling column. Four of the said boilers B,
B1, B2, B3, are represented in the Drawings, but any suitable number may be used.
The said boilers communicate one with the other by incans of a distributor C of well-
known construction, such as is used in gas works and other manufactories. The
said distributor allows one or more of the boilers to be isolated successively for the
purpose of emptying, cleansing, and refilling it or them without interrupting the
distilling operation. Supposing there to be four boilers used and only one of them
to be isolated at a time, then there will always be three boilers in the circuit. The
steam required for the distillation, and which may be the exhaust steam of the
motive engines, passes through the pipe T into the distributor C, and then through
the pipe T into the boiler B (previously filled). The steam passes out from the
said boiler B through the pipe T and again enters the distributor, passing out
therefrom through the pipe T and entering the second boiler B¹. In like manner
the steam is made to enter the third boiler (which has just been filled), so that the
fresh steam enters that boiler in which is the ammoniacal liquid from which the
last traces of ammonia are to be removed. On leaving the boiler B the steam
after having re-entered the distributor passes through the pipo V into the distilling
column A, where it effects the distillation of the ammonia, either as caustic aminonia,
or combined with carbonic acid.

page_text: The last compartment P of the distilling column acts as a refrigerator, in which
the vapour of water is condensed, so that the ammonia alone passes out through the
pipe Az. Instead of using water in the coil of pipes St, I prefer to use the liquid
which is to be distilled so as to heat it to a certain point previously to the distilla-
tion, a special coil of pipes for the water may, if desired, be used. Above the
compartment P is a regulating apparatus actuated by the variations of temperature.
The said apparatus consists of a float F in a reservoir R, containing a small quantity
of water. The gases emitted in the process of distillation communicate more or
less heat to the said water, and when the temperaturo is sufficiently high they cause
the said float to move downwards and to open a cock or tap G, admitting water or
liquid into the coil of pipes. Instead of acting upon the liquid in the coil of pipes
the said float may be made to act upon a butterfly valve or other arrangement,
regulating the admission of steam to the distilling apparatus. The use of the said
apparatus is of great importance as the vapour of water must not be allowed to
condense in saturated brine, otherwise the brine will be diluted. The liquid to be
distilled (after leaving the refrigerating coil if utilized as described) is conveyed
through the pipe L into the distilling column, either into the upper part of the said
column, as represented in the Drawing, or if preferred into the lower part thereof,
and in the latter caso the liquid which has once been introduced into the upper
compartiments will never be renewed. The liquid passes out from the distilling
coluinn into the pipe, which conveys it to the distilling boiler, which has just been
emptied and charged with lime, before being charged into the boiler the lime may
be slaked, but I prefer to utilize the heat produced in the slaking process, and to
introduce the lime in blocks or pieces as it leaves the lime kiln by the door S into
the basket 2, which retains the unburnt parts and foreign matters. When the boiler
is emptied the residuum is removed by the door I, which supports the bottom H
of the basket. Instead of the lime basket p being mounted in the centre of the
boiler it may be placed at the side, the residuum being then removed through a
doorway in the side of the boiler. The steam pipe might then be placed in the
centre and be used also to empty the boiler.
It will be understood that by the arrangements herein-before described the dis-
engagement of ammonia produced by the action of the rising liquid upon the lime
is successive, and can never exceed certain limits so as to become dangerous, for as
soon as the pressure within the boiler which is being filled becomes too great it
prevents the liquid from entering the apparatus until such pressure is sufficiently
reduced.
The heat produced by the slaking of the quicklime produces steam, which
steam may be utilised in the distilling column, which it may enter either at the
bottom through a pipe V, or through the pipes V, as shewn in the Drawing.
Among the improvements in details, I wish to point out the false bottoms used
in my absorbing columns X, which false bottoms are made convex, and are per-
forated with tapering holes, being also serrated at their periphery. This shape
produces perfect absorption of the heat. i is a lever for actuating the valve k
which is intended to arrest the descent of the liquid where the lower compartment
of the distilling column O contains the quantity of liquid required for one boiler,
which quantity is indicated by a gauge glass on the side.
M are overflow pipes through which the liquid descends. N are tubes through
which the ammonia and steam pass. y is a safety valve at the end of a metal pipe
containing water or petroleum to prevent the ammonia from corroding the said
valve and its seat. If preferred an ordinary safety tube may also be used. Z aro
the flow-off cocks of the boiler.
The second arrangement of apparatus is represented in Figs. 4 and 5 of the
accompanying Drawings, Fig. 4 being a sectional elevation and Fig. 5 a plan partly
in section.
The arrangement of apparatus represented allows of a continuous distillation
being completely effected in one distilling column. The distilling columns hitherto
known do not allow of lime being used.

page_text: "
I have applied to the said apparatus the same means which I use in my apparatus
described in the Specification of my Patent of 1872 for absorbing carbolic acid, in
The distilling
which liquid charged with solid matter in suspension is treated.
column is divided into two parts, the upper part A includes the compartinents A',
A3, A3, A4, A5, Aº, A7, A8, and is for distillation without lime. As represented in
the Drawing it is of similar construction to the distilling column herein-before
described in relation to Fig. 1, but it might be constructed like the lower part B
of the column which is used for distilling with lime, and includes the compart-
ments B, B', B4, B5, B, B, B, Bº, B10, B, and B¹. P, P¹, P, P³, arc
reservoirs, each provided with a conical grated false bottom G, and which contain
Four of the said
the quicklime required for distillation with all its impurities.
lime reservoirs are represented in the Drawing. One or more than one of the
said reservoirs are kept working, whilst the others are by means of the cocks or
taps,,, isolated from the circulation in order to their being filled with lime
through the door p, and emptied of the impurities they contain through the
‹loor p¹.
The liquid having passed into the lower compartment As of the part A of the dis-
tilling column as herein-before described with reference to the first arrangement, and
consequently after all the carbonate of ammonia has been distilled passes into the lime
reservoir which has been connected to the circulation by opening the cock or tap r,
and the said liquid charged with lime flows out through the cock or tap from the
lime reservoir into the part B of the distilling column. As shewn by the Drawing
the said part B of the column is a cylinder divided into several compartments by
horizontal partitions C perforated by a central hole t. Upon each partition rests
a convex falso bottom F perforated with holes and serrated and guided by rods T.
The liquid charged with lime descends into the said part 1 of the distilling column,
and passes out therefrom completely distilled through the cock or tap R.
All the arrangements described in the Specification of my Patent of 1872 with
reference to my absorbers of carbonic acid gas may be applied to this apparatus.
The steam and gases disengaged in the lime reservoirs P, P₁, P, P³, escape
through the cock or tap, and are thus utilized for distillation in the pari A of
the column. From the elevation of the overflow pipe 9 the ammoniacal liquid,
which is free to rise in the compartiment A of the column, keeps the grated
bottom G of the lime reservoir constantly immerged so that the lime dissolves
But should the action of the quick-
easily gradually falling in as it is dissolved.
lime become energetic, the gases disengaged being unable to escape in sufficient
quantity through the cock or tap (the flow through which cock is regulated
beforehand) forces back or arrests the liquid so that it only immerges a small quantity
of the lime. The dissolving of the lime is thus regulated automatically, that is to
say, regularly.
For the part B of the column to work well the steam employed for distillation,
and which passes into the apparatus through the tube X, should be introduced in
The exhaust steam of a
intermittent jets so as to allow the liquid to descend.
steam engine is therefore suitable for the purpose.
If preferred parts of the two arrangements herein-before described may be
combined to form another complete distilling apparatus; thus with the boilers
B, B1, B2, B3, of Figs. 1 and 2, may be combined the lower part B, represented in
Fig. 4.
My Invention relates further to an additional apparatus common to all.
Whatever be the distilling apparatus used, I find it advantageous to employ a
vacuum so as to effect the distillation with steam of a reduced pressure. The vacuum
may in this case be made in the apparatus herein-after described under the head of
preparation of the ammoniacal brine" and which contains the water or brine by
which the ammonia is to be absorbed.
The vacuum may be produced by any suitable known means, and between the
absorbing apparatus and the air pump or vacuum-forming apparatus I interpose
lixiviating apparatus, such as are herein-after described, and in which the water or

page_text: brine which is to absorb the ammonia is first made to pass. A water piston pump
may be used for creating a vacuum in the bicarbonate filter.
My Invention relates also to the preparation of ammoniacal brine.
The most favourable situation for a inanufactory of carbonate of soda from am-
monia is upon a salt water stream or a well yielding saturated brine. More especially
as regards the preparation of ammoniacal brine 1 assume that the solution of salt is
obtained from such a source. If not, it will be necessary first to dissolve the salt,
then the brine thus obtained may be treated in the same manner as natural brine.
When I began to manufacture at the Dombasle works, near Nancy, which were
supplied from a salt water well, I was stopped for several months by difficulties
arising from the nature of the water which held in solution salts of magnesia and of
lime, was not able to overcome them without long and costly experiments, and
this will be readily understood if it be considered that previously to my process
soda had never been obtained on a manufacturing scale from natural waters.
It is well known that the salts of lime and of magnesia contained in salt water
aro precipitated by alkaline carbonates.
It is also well known that heat and agitation facilitate the ulterior deposit of the
said precipitates; but these data are not sufficient to resolve the question of purify-
ing salt water.
viz.
In carrying out my improvements I was guided by several important facts,
1st. That when, by the addition of lime to impure brine, the salts of magnesia
are replaced by salts of lime, in the formation of which salts the magnesia is
precipitated, the salts of lime are afterwards easily precipitated by the addition of a
small quantity of carbonate of ammonia.
2ndly. That carbonate of ammonia does not entirely precipitate the salts of
magnesin unless the said carbonate of ammonia be in great excess.
3rdly. That it is necessary after the precipitation of salts other than chlorido of
sodium to add a further quantity of such chloride of sodium because the presence
of the said other salts previously in the solution prevented the liquid from contain-
ing the quantity of chloride of sodium required for the manufacture of soda. The
two first of these observations led me to discover two really industrial modes of
purifying water, and to these modes of purifying water 1 add. a treatment in con-
formity with the third observation.
As most of the soluble alkaline carbonates are expensive it becomes a matter of
importance to utilise the carbonate of ammonia which is produced in my manufac-
ture of soda.
I will now proceed to describe the two processes of my Invention, and I do not
hesitate to say that as far as my experience goes I prefer the second to the first,
which is a special mode of purification more or less analogous to what has been de-
scribed by others. The second mode, on the contrary, is elfected during the course
of the manufacture itself, and is a necessary consequence of the operation cm-
ployed.
First Process. I mix lime with salt water, stirring or agitating the mixture for a
certain time. The effect of this operation is to transform the salts of magnesia into
salts of lime, which are immediately precipitated if the brine be already saturated
with salts of lime, or the salts of lime and also the caustic lime which is being
dissolved, may be easily precipitated by adding thereto carbonate of ammonia. The
said precipitation is effected by adding to the brine a suitable quantity of carbonate
of ammonia after the decomposition of the salts of magnesia and the deposit of
the magnesia and lime in suspension.
The said operation may take place in the same vessel, but it will succeed better
if by decantation the liquid be made to pass into another vessel in which the
carbonate of ammonia is added. It is effected by simply causing the decanted
brine to pass into the lixiviating apparatus which retain the ammonia escaping
from certain apparatus used in the manufacture; care being, however, taken that

page_text: the said ammonia be not combined with more than one equivalent of carbonic
acid.
After this purification is finished the saturation of the ammoniacal bring to tho
required density is resumed either immediately or later by the addition of sea
salt.
Second Process.-In this process the purification of the salt water is effected during
the preparation of the ammoniacal brine, which preparation includes the series of
operations herein-after described.
The apparatus which I have invented for the said operations are represented by
Figs. 6 and 7 of the accompanying Drawings, Fig. 6 being a sectional elevation, and
Fig. 7 a plan view of the whole.
The brine to be saturated with ammonia is contained in one of two reservoirs R
or R', of which reservoirs there may be any suitable number, more or less. A is
the dissolver of ammonia. I will suppose that it is required to saturate with
ammonia the brine contained in the reservoir R. I put it in communication with
the dissolver A by means of two cocks or taps rand. The ammonia from the
distillation passes into the dissolver through the pipo T, which opens into one of
the perforated false bottoms F constructed as herein-before described in relation to
the distillation. A current is then produced in the apparatus, so that after a
certain time all the liquid in the reservoir R will have passed into the dissolver
and have absorbed the ammonia. Having ascertained the level in the reservoir R
at the beginning of the operation I stop the inlet of the ammonia when I discover
that its level has risen so as to correspond with the quantity of ammonia I wish to bo
absorbed. T is a pipe for evacuating the inert gases charged with ammonia which
are disengaged at certain periods of the operation, the said ammonia being collected
in a lixiviating apparatus.
The vacuum referred to under the first head of the Invention may be most
advantageously applied after the lixiviating apparatus herein-before described.
The necessary agitation and circulation are produced by the absorption of the
ammonia, and also by an agitator W. After the motion of the agitator has ceased,
the agitation it produced co-operates in the precipitation of the deposit at the
bottom of the reservoir; suitable agitation might also be produced by causing the
liquid to fall in a cascade or otherwise, or by means of a centrifugal pump placed
between the reservoir and absorber so as to produce an active circulation of the
liquid. I prefer, however, the more simple arrangement represented in Fig. 10,
which consists of a screw H caused to rotate at a velocity of several hundred revo-
lutions per minute in a cylinder C communicating with the absorber by means of
one of the tubes t or t, and by the other with the reservoir containing the brine
which is to be rendered ammoniacal.
The necessary heat is obtained from the absorption of the ammonia, and the
temperature is regulated as required by a refrigerating coil S. I then give to the
brine its required density. V is a pipe through which I introduce refined or
pounded salt into the absorber during the operation, the proportions being regulated
by a wheel divided into several compartments m. The agitation facilitates the
dissolution of the salt. The salt water may be previously heated so as to evaporate
a portion of the liquid brine before it is conveyed to the apparatus. It then enters
the apparatus, holding in suspension the excess of salt required, and further addi-
tion of salt thereto is unnecessary. In the arrangement just described for the
purpose of giving the right proportions of ammonia it is necessary that the cocks
or taps or valves should be turned by hand whenever one of the reservoirs R or R¹
is saturated with ammonia so as to begin the saturation of the other, but the opera-
tion of proportioning the ammonia may also be performed automatically.
In 1863 I described an apparatus for this purpose based indirectly upon the
increase of volume of the natural brine produced by each dose of ammonia, taking
into account the fact that this augmentation is accompanied by a proportionate
decrease in the density of the said brine. The said apparatus acted solely in
accordance with the density of the brine. But as then the brine received only an

page_text: insignificant quantity of carbonic acid by ascertaining the difference of density it
was possible to give the requisite proportions of ammonia exactly enough. But as
I now introduce large and varying quantities of carbonic acid into the liquid the
above process is impracticable, because the addition of carbonic acid while it scarcely
changes the volume of the liquid greatly increases its density. A self-acting
apparatus must therefore be based upon the increase of volume of the brine and
not upon its density, which would be deceptive from the variations in the quantity
of carbonic acid introduced. For this purpose I have invented the means of
utilizing the regular increase of the volume of natural brine produced by each dose
of ammonia absorbed. I put the dissolver into communication with two reservoirs,
one of which serves for measuring the brine and introducing it into the said
dissolver, whilst the other draws out therefrom a corresponding quantity of
ammoniacal brine of the required richness. Thus I regularly introduce into the
dissolver given quantities of natural brine and draw off from the said dissolver
corresponding quantities of aminonincal brine when the liquid has attained its
required richness. For this purpose the two reservoirs above mentioned arc
provided with a double lever motion actuated by a float in one of the said reservoirs.
The said float, which when the ammoniacal brino in the reservoir has reached the
required level, nets upon a valve or cock so as to cause it to evacuate the ammoniacal
brine, and as soon as this is evacuated the said float having descended acts upon
another valve or cock in the other reservoir so as to introduce into the dissolver tho
required amount of natural brine.
Fig. 8 represents an apparatus constructed according to this part of the Invention.
A is the dissolver; X is the reservoir containing the salt water, which passes into it
through the pipe t from a tank in which a constant level is maintained; X' is the
reservoir into which the ammoniacal brine is conveyed by the pipe t; S and S¹
are valves with double seats; F is a float free to move on the rod o.
The action of the apparatus will be readily understood from what has been stated.
When the dose of ammonia has been absorbed, the level of the liquid rising in the
reservoir X and in the dissolver raises the float F, which lifts up the rod o and ai
the same time the two valves S and S', which are kept in their place by a counter-
poise or 9. When the valve S is raised it stops the passage of salt water into
the reservoir X, and allows the required quantity of salt water which is contained
in this reservoir to enter into the dissolver through the pipe T. At the same time
the valve S closes the communication between the reservoir X and the dissolver A,
and allows the ammoniacal brine to flow out through the pipe I. The apertures
nre regulated so that the brine from the reservoir X passes entirely into the dissolver
before the reservoir X is quite empty. The float F then descends and draws down
the rod o, thus causing the parts to resume their former position. The weighted
lever L, which serves to keep the valves S and S¹ firmly in their proper position, is
provided, as seen in the Drawing, with two rolling weights q and q which travel
from one end of the lever to the other. For the said rolling weights q and q
mercury may, if preferred, be substituted, the said mercury being made to travel
from one end of the lever to the other (Fig. 9).
The dosing operation being finished the deposit of lime, magnesia, and other
deposit is at the bottom of the reservoir R (Figs. 6 and 7). 1 force all this deposit
into a decanter D, through a pipe L, or other known means may be added so as to
increase the travel of the liquid drawn off and to clarify it before it reaches the
outlet U, but I do not consider these means necessary. The deposit in the decanter,
thanks to the scraper M, rises in the pipe I and is drawn off through the cock or
tap b. The said deposit with the small quantity of liquid which accompanies it
is conveyed to one of the distilling boilers for the ammonia to be taken from it.
All the ammoniacal brine may also be forced from the reservoir R or from the self-
acting measuring apparatus into the decanter and from thence into the filter
through the pipe L', or only the lower layer may be made to pass into the decanter,
the remainder passing into the filter through the tube N. The arrangement of the
decanter may be varied.

page_text: After the decantation it is useful to filter the ammoniacal liquid in order to be
sure that no deposit is carried away. For this filtration as the liquid only retains
very minute particles it is necessary to use very close woven fabrics, and con-
sequently a pressure of several atmospheres. In the Drawing is represented a
cylindrical filter B capable of supporting a very high pressure. In the said
cylindrical filter B a sack or bag is contained in the perforated cylinder O, and when
the said sack or bag is filled with deposit the filter is stopped and the said sack
or bag is replaced by another, it will therefore be necessary to have several filters.
The filteration may if preferred be effected from the outside to the inside by
placing a sack round the cylinder O, the deposit being then removed through the
door d. On leaving the filter the clarified ammoniacal brine is conveyed to the
refrigerator. The said refrigerator consists of two series of concentric pipes, the
inner pipes communicating one with the other alternately by semicircular or
curved joint pipes on their ends, and the outer pipes communicating togetherby
vertical pipes on the ends of each alternato pair of pipes, the refrigerating water
being made to pass through the inner pipes or through the annular space between
the two pipes. Any suitable construction of refrigerator may be used.
In the refrigerator represented in Fig. 6 the ammoniacal brine enters through
the tube and passes out through the tube h after having passed through the
whole circuit formed by the annular space between the two pipes, the refrigerating
water flows through the pipe Z.
It will be seen that the curved pipes Z' connect the inner pipes Z together, and
the T pipes Z connect the outer pipes Zone with the other. The dosing and
absorption of the ammonia may also be effected, as stated with reference to the
apparatus herein-before described and represented in Figs. 6 and 7, by means of
pure water instead of salt water, the said ammoniacal water being then used for
dissolving sea salt.
My Invention relates, thirdly, to the addition of natural brine and salt in the
absorbing apparatus.
The principle operation in the manufacture of carbonate of soda by the am-
moniacal process is the reaction of the carbonic acid upon the ammoniacal brine.
In the Specification of my Patent of 1872 I described apparatus for obtaining this
Into this
reaction, which apparatus 1 nained the absorber or absorbing column.
apparatus I introduce natural brine or common salt, as I shall now proceed to
describe.
1. Ever since I began to manufacture I endeavoured to retain in the reaction
apparatus the ammonia which the motion of the gas tends to drive out from it.
The mode of introducing the liquid described in the Specification of my former
Patents tend to this end. I have discovered other means of effecting it which
complete what I have already obtained. The said means consist in introducing
natural brine by the top of the column either through a tube placed on the side
of one of the upper apparatus or through a pipe passing down through the cover of
the column.
II. I have remarked an important fact connected with my manufacture which
is, that salt becomes soluble in liquid more or less saturated with carbonic acid,
though it was no longer soluble in ammoniacal brine. 1 take advantage of this
fact to obtain from the liquid a larger quantity of bicarbonate of soda by introducing
near the top of the column with the salt water, as herein before described, salt in
suspension or simply refined salt through a suitable distributor. The salt thus
introduced into the column is dissolved before it reaches the bottom from the
presence of carbonic acid and it thus takes part in the reaction.
Salt in suspension may also be introduced into the ammoniacal brine before its
introduction into the columns. This means of using salt in excess, in quantity
corresponding with the quantity of ammonia in the ammoniacal brine increases the
yield of bicarbonate of soda.
My Invention relates, fourthly, to the dissolution of hydrochlorate of ammonia.
In the manufacture of bicarbonate of soda it is necessary that care should be
taken to cool the reaction apparatus or to prevent the heating of the liquid so as to

page_text: obtain a reaction as complete and as speedy as possible. But this circumstance
which is favourable to the production of bicarbonate of soda may, from the very
intensity of its action, cause the precipitation of crystals of hydrochlorate of
aminonia which would pass out in the same solid state as the bicarbonate and could
not be separated therefrom by ordinary means. This result is still more to be feared
with the improvement just described, viz. the addition of salt in excess.
:
The means of obviating this defect is to use heat in a suitable manner, the
solubility of hydrochlorate of ammonia being increased by the action of heat much
more rapidly than the solubility of bicarbonate of soda. Thus by increasing the
temperature to a certain degree all the hydrochlorate of ammonia may be dissolved
with only an insignificant portion of bicarbonate of soda; but it will be understood
that the necessity of employing refrigerating means for the reaction and heat to
prevent the formation of crystals of hydrochlorate requires the said two opposite
incans to be used separately.
I apply this principle in several ways, and there may be others equally effective
for carrying out practically the same principle of using successively two different
temperatures for two different purposes.
It may be carried into effect in the absorbing column. Instead of introducing
the carbonic acid gas at the lower part of the apparatus it is introduced at a certain
distance above the bottom, and in the lower compartment is placed a coil of pipes
or other well-known means of heating the liquid.
I prefer, however, to effect the heating in a special apparatus in which it is easier
to agitate the liquid by suitable means and to prevent the transmission of the heat
to the liquid subjected to reaction, or the water used for lixiviating the bicar-
bonate may be heated to a certain temperature. It will then dissolve the
crystals of hydrochlorate of ammonia whilst traversing the mass of bicarbonate.
My Invention relates, fifthly, to the filtration of the liquid containing the
bicarbonate of soda
When the manufacture is carried on on a large scale, which is possible by cm-
ploying the means which I have invented, and which I have done for some years,
multiple and intermittent filters should be avoided.
I will now proceed to describe a continuous filter constructed according to my
Invention. The said continuous filter is represented in Figs. 11, 12, and 13 of the
accompanying Drawings, Fig. 11 being an elevation partly in section, and Fig. 12 a
plan, Fig. 13 is a plan of the part B separately.
The said filtering apparatus consists of a circular or other shaped reservoir A,
divided into a certain number of compartments, of which eight are represented in
the Drawing. Each compartment is covered over by a grating or perforated plate
G, and a suitable filtering inedium, such as canvas, flannel, or other suitable material
with a perforated plate or wire gauze over it to preserve the material.
Each of the said compartments communicates with a bottom plate P, in which
are corresponding holes or apertures. The said plate P is supported on a lower
table P¹, which forms the upper part of a chest C, represented in the Drawing as
divided into three compartments and one solid portion. A vacuum is constantly
created and maintained in the chest C, and gives the action required in the
operations. The table P1 presents a hole opposite to each compartment of the
reservoir A, except oue. The circular reservoir A rotates slowly in the direction of
the arrow with its plate P upon the table P which is stationary, and when in the
position represented in the Drawing each compartment has successively the same
destination.
I will now proceed to describe the working of the apparatus at a time when all
the said compartments have a different destination. The compartment A' of the
reservoir A communicates with the exhaust punp by means of a separator, in which
the liquid settles and draws in the hydrochlorate of ammonia containing the bi-
carbonate of soda. The liquid from the column flows through the pipe T, and
passes through a pipe perforated with holes or grooved so that the compartment A¹
2

page_text: is being filled. A vacuum is made in the chest C by exhaustion in the pipe t, which
pipe communicates, as has been stated, with the exhaust pump by means of a sepa-
rator not shewn in the Drawing. It will be seen that the compartments C, C, C
of the chest C, Fig. 13, are in communication with the compartments A', A, A³, of
the reservoir A. Nothing passes now into the compartment A³ in which the bi-
carbonate is dried for the first time. The compartment A3 receives from one of the
reservoirs R¹¹ or R₁ by means of the pipe T¹ the water which has already served
for two previous lixiviations as herein-after described, and thus it receives a first
lixiviation. The said three compartments of the continuous filter thus communi-
cate with the compartments C, C, C, of the chest C, and all the liquid passes into
the separator herein-before alluded to, from which it is taken to be distilled. In
the compartment A of the filter a second lixiviation of the bicarbonate is effected
by means of liquid contained in one of the reservoirs R' or R", which liquid
obtained from a previous lixiviation enters through the pipe T". The said liquid
is collected in the compartment c' of the chest C, and the vacuum causes it to pass
up through the pipe t¹ into one of the separators or reservoirs R or R, the use
of which is herein-before described. The compartment A of the filter serves for a
last lixiviation with pure water, which is converted from the reservoir R through
the pipe T, and it is the liquid thus collected which passes into the compartiments
C, C, and C7 of the chest C, and from thence into one of the reservoirs R' or R"
through the pipe t". Nothing now enters the compartiments A° and A7, which com-
plete the drying operation, and the liquid from which passes also through the pipe ("
into the said reservoir R¹, R. Lastly, the compartiment As of the filter is in the
position represented in the Drawing ready for its bicarbonate to be discharged, which
discharge may be effected by means of a spade or a chain of buckets which would
discharge the bicarbonate upon the plate or table of a self-acting weighing machine.
The partitions S above the filtering surfaces may, if preferred, be omitted. The bi-
carbonate would then be scraped off by means of a fixed scraper shaped like a
ploughshare, which would eject it from the filter, as is the case in certain mortar
imachines and other apparatus. The aperture in the said compartment As is oppo
site the solid portion of the chest C. It will be readily understood that as the
reservoir rotates constantly each portion of the surface of the filter receives succes-
sively some of the liquid from the absorbing columns, and the liquid deposits the
bicarbonate which is lixiviated methodically as many times as is required, and
when sufficiently dry is removed from the filter. Motion may be communicated to
the filtering reservoir A, as represented in the Drawing, by a pinion actunted from
the fast and loose pulleys X, X', a toothed rim being fixed to the reservoir but any
other suitable means, even hand gear, may be substituted. The motion of the
apparatus should be very slow or intermittent, so as to cause the said apparatus to
stop for a short time whenever it has travelled through the distance of one com-
partment. It is through the pipe V that the pump creates a vacuum in the
reservoirs R, R, R, R, and through the pipe V the water is conveyed to the
reservoir R. I have represented the reservoirs R', R", R, R as being arranged
in pairs, so that one is being filled whilst the other is being emptied. In the
Drawing the valves opening and closing the different apertures are represented as
actuated by hand; but it will be readily understood that by means of floats acting
upon valves or cocks they may be made self-acting. The float of the reservoir
from which the liquid is exhausted may be made to open the valve or cock of the
vacuum pump and the exhaust pipe of the filter, whilst at the same time it closes
the discharge cock and opens the cock of the other reservoir as well as an inlet cock
for air, and closes the other means of communication. It is evident that the shape
of the filter, its arrangement, its size, the number of compartments, may be varied
in various ways without the apparatus being otherwise than continuous.
What constitutes the chief feature of this apparatus is its being continuous,
effecting simultaneously all the parts of the operation, the salt it contains being at
the same time subjected to all the different stages of the operation.

page_text: And it will be readily understood that without departing from the principle
upon which it is based the means of execution may vary greatly.
Figs. 14, 15, and 16 represent the said apparatus constructed of a cylindrical
form and rotating round a horizontal axis. The parts corresponding with those of
Figs. 11, 12, and 13 being marked with the same letters of reference a further
description is unnecessary. Other forms may be adopted.
The apparatus herein-before described and illustrated in the accompanying
Drawings may be constructed of any suitable metal, by preference cast or wrought
iron, according to the purpose for which they are used, care being taken to protect
by well-known means such parts as are or may be in contact with substances likely
to corrode them.
Having now described the nature of my said Invention and in what manner
the same is to be performed, I wish it to be understood that I do not confine
myself to the precise details herein-before described and illustrated in the accom-
panying Drawings as the same may be varied without departing from the nature
of my said Invention, nor do I claim the details of the said apparatus, except as
parts of apparatus for carrying out the inanufacture of carbonate of soda by the
ammoniacal process. I claim as my Invention--
Firstly, with reference to the distillation of ammonia, the two apparatus herein-
before described and represented in Figs. 1, 2, 3, and 4, and 5 of the accompanying
Drawings constituting each separately a complete distilling apparatus.
Also the combination of parts of the two said apparatus so as to form another
complete distilling apparatus.
Also the means employed in the first apparatus for treating the liquid by quick-
lime, that is to say, placing the quicklime in a separate compartment in commu-
nication with the liquid, and in which the lime arranged vertically is gradually
attacked by the rising liquid.
Also the means used in the second apparatus for treating the liquid by quick-
lime consisting essentially in placing the said quicklime in a separate compartment
in constant communication at its lower end with the liquid, and in which the line
gradually falling lower and lower is gradually acted on by the liquid.
Also the arrangement herein-before described which by means of the elevation of
the overflow pipe, and the previous adjustment of the cock or valve for disengaging
the gas and vapour, produces automatically the regular action upon the lime which
is essential to a continuous apparatus.
Also utilizing the heat given off by the hydratation of the lime for the distillation
of the liquid.
Also the application of the herein-before described regulator of temperature, to
preventing the vapour of water being carried off with the ammonia evolved in the
distillation.
Also the application of a vacuum to the said distillation effected by the inter-
position of intermediary vessels.
Secondly, with reference to the preparation of the ammoniacal brine, 1 claiu-
The first mode of purification herein-before described, consisting essentially in
the use of carbonate of ammonia, which is rendered efficacious in small quantities
by the previous conversion of salts of magnesia into salts of lime.
Also the whole of the operations herein-before described in respect of the second
process combining the purification of the brine with the absorption of the ammonia
with or without automatic dosing, with or without filtration, with or without
the subsequent refrigeration.
Also the addition of sea salt to purified brine in order to restore the saturation
which disappeared through the precipitation of the noxious salts, whatever be the
mode of adding the said sea salt.
Also the purification of brine already formed effected by an operation forming
part of the manufacture of soda, that is to say, the addition to such brine of the
ammonia required for the manufacture of soda in order to precipitate therein the

page_text: noxious salts dissolved therein, and which should be eliminated previously to effecting
the decantation or filtration.
Also the means described of dosing the ammonia by means of apparatus operating
independently of the density of the liquids and directly according to their bulk.
Also the apparatus described for effecting the absorption of the ammonia in a
receptacle which by a system of circulation serves to give the ammonia to the
brine contained in other receivers.
Thirdly, with reference to the addition of natural brine and salt in the absorbing
apparatus, I do not claim as my Invention the use of brine as a means of lixiviation
nor its introduction or the introduction of salt into any apparatus whatever, even
if the reaction took place in it.
But I claim the introduction of natural brine near the outlet of the gas into an
apparatus in which the ammoniacal brine previously formed is subjected to the
reaction of carbonic acid.
Also the introduction of salt into such an apparatus by any means.
Fourthly, with reference to the dissolution of hydrochlorate of ammonia, I claim,
the process herein-before described consisting in the application of heat to the
ammoniacal liquid from the absorber after the reaction produced by the carbonic
acid is completed for the purpose of dissolving the crystals of hydrochlorate of
ammonia in such conditions that it will not interfere with the low temperature
required for the reaction.
Fifthly, with reference to the filtration, I claim the continuous filters herein-
before described, in which bicarbonate of soda in all the compartments is simulta-
neously in different stages of the operation, and in which the said bicarbonate in
cach compartment is successively in a different stage of the operation, the said
continuous filters being constructed and disposed substantially as herein-before
described and illustrated in Figs. 11 to 16 inclusively of the accompanying
Drawings.
In witness whereof, I, the said Ernest Solvay, have hereunto set my hand
and seal, this Twenty-third day of October, in the year of our Lord One
thousand eight hundred and seventy-six.
ERNEST SOLVAY. (L..S.)