IMPROVEMENTS IN MANUFACTURING AND REFINING. SUGAR
Year: 1849

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the County.
of Middlesex, Mechanical Draughtsman, send greeting.
77
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing, date at
Westminster, the Twenty-third day of August, in the thirteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Alfred Vincent Newton, Her especial license, full power, sole privilege
and authority that I, the said Alfred Vincent Newton, my exors, adñors,
and assigns, and such others as I, the said Alfred Vincent Newton, my exors,
adors, or assigns, should at any time agree with, and no-others, from time
to time and at all times during the term of years therein mentioned, should
and lawfully might make, use, exercise, and vend, within England, Wales,
and the Town of Berwick-upon-Tweed, and in all Her Majesty's Colonies and
Plantations abroad, and in the Islands of Jersey, Guernsey, Alderney, Sark,.
and Man, an Invention of "IMPROVEMENTS IN MANUFACTURING AND REFINING.
SUGAR," being a communication from a Foreigner residing abroad; in which
said Letters Patent is contained a proviso obliging me, the said Alfred
Vincent Newton, by an instrument in writing under my hand and seal,
particularly to describe and ascertain the nature of the said Invention, and
in what manner the same is to be performed, and to cause the same to be
enrolled in Her Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said in part recited
Letters Patent, as in and by the same, reference being thereunto bad, will
more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Alfred Vincent Newton, do hereby declare that the nature of the said Inven-
tion, and the manner in which the same is to be performed, is particularly
described and ascertained in and by the following description thereof (that is
to say): -
This Invention, as communicated to me by my foreign correspondent, relates
to an improved method of separating the crystallizable saccharine principle
from the juice of the sugar cane or beet root, or from other vegetable juices,
whereby a larger quantity of sugar may be obtained than by the methods at
present employed, the sugar being also of superior quality.
The objects of the Invention are effected by treating the saccharine fluid
with a certain chemical agent or agents whereby the disposition to chemical
change or fermentation inherent in all vegetable juices, is effectually checked,
or by precipitating and separating the crystallizable sugar from the fluid in
which it. exists as, an insoluble compound by adding to the fluid certain
chemical substances, which possess the property of combining with sugar to
produce the effect just mentioned.
. I will now proceed to describe the Invention under three separate heads,
viz., the treatment of the juice as it flows from the cane, the precipitation
of the saccharine particles, and lastly, a mode of effecting the defecation
of the juice.
With reference to the first part of the Invention it may be remarked, that
a source of great loss in the extraction of sugar from the juice of the cane or
beet root originates in the tendency of the expressed juice when exposed to the
atmosphere to pass into a state of chemical change or fermentation which is
carried on at the expense of the saccharine principle contained in the fluid,
the elements of the saccharine matter assuming another form, and being
accordingly lost to the manufacturer. In proportion as fermentation goes on,
the quantity of crystallizable, sugar is diminished; it is therefore an important
object under the old method to expedite the different operations, even at great
inconvenience, in order to prevent that loss of saccharine matter which would
ensue if the expressed-juice-were kept for any length of time before being.
boiled down. With every precaution, however, a very considerable-loss-
always occurs both in consequence of the change which takes place to a
greater or less extent in the juice and from the quantity of sugar left in the
solid residual matters, and wasted in washings of apparatus, &c., and which can
only be extracted when means are employed to prevent the chemical alteration
which would be sure to take place when these vegetable products are kept in
contact with a large quantity of water. The first part of the present Inven-

page_text: tion relates to the employment of a class of antiseptic substances, hereafter,
specified, which possess the property of preventing the accession of ..that
chemical. change or fermentation so destructive to the saccharine matter.
contained in the vegetable juice:
The second part of the Invention .refers. to the .separation of the .crystalliz-
able sugar by its precipitation as an insoluble compound with. any of the
different agents hereafter. described as capable of effecting that object: this
process may. cither.be employed alone or in. combination with the first part, of
the Invention. This part also relates to the preparation. of the precipitating.
agents and to their regeneration after having been employed in precipitating
the sugar.
The third part.relates to the employment of certain chemical agents together.
with or as substitutes. for lime as defecators or purifiers.of sugar.
:
PART FIRST. TREATMENT OF CANE JUICE, JUICE OF THE BEET ROOT, &c.
DY. ANTISEPTIC AGENTS.
,
of
In order that the saccharine: solution may be prevented from passing into a
state of fermentation, I adopt the following plan. of treatment:-The moment
the cane is cut into pieces the separated portions or slices. are. plunged into a
solution of sulphurous acid, of an acid sulphate, or of any other. antiseptic
substance, no matter whether it be in a state of solution. or merely mixed with
water. The bisulphate of. lime employed. at..the moment in which. the vege-
table. cells are. laid open to the, influence. of the air, prevents the action of
oxygen upon the azotized matters present in. the sap these are conse-
quently preserved from.passing into a state. of fermentation. The. .presence
the base or.neutral salt does not permit of the transformation of the sulphurous
acid into free sulphuric acid, which. would. act. injuriously upon the:, sugar.
The sulphuric acid which is formed: passes.to a portion of the lime, converting
that base into a. sulphate, a substance, which is, not only innoxious, but which
seems to play a useful part. in the process. The bisulphate of. lime entirely
prevents any chemical change from taking place in. the, crystallizable sugar
originally present in the sap of the cane, and permits of the extraction of the
whole quantity of that sugar. in the crystallized form by rapid or slow evapora-
tion either in the air..or in. vacuo. In order that..this process..may succeed
completely, it is necessary that .the antiseptic agent .be intimately mixed with
the cane juice.as soon as the cells containing it are broken down either by
crushing, rasping,..or: slicing, preventing as much..as possible. the previous
exposure of the sap to the influence of the.atmosphere. By operating. thus the
juice will be preserved: in: its.. normal state, it will neither undergo chemical

page_text: change nor acquire color, there will be no fermentation arising from decom-
position or modification of the substances contained in the juice, the azotized
compounds will remain unaltered, and the formation of ammoniacal salts will
be effectually prevented. If the bisulphate of lime be employed only as a
preservative agent a very weak solution of that salt in water is used. The
solution of bisulphite may be added to the cane juice by applying it over the
cylinders of the crushing mill, over those of the rasping machine, or to the
portions of cane as they fall from the slicing machine. The liquid expressed
from the sliced cane or flowing from the crushing mill may be submitted to
evaporation in the same manner as any saline solution which is unalterable in
the air. The solution is heated up to 100° Centigrade for some minutes, and
then left to settle so that the more limpid portion may be drawn off from the
precipitate, it is then passed through bag filters to perfectly separate the solid
matters held in suspension. The filtered liquor is now evaporated; this
evaporation may be conducted without the application of heat, (that is to say)
by exposure of a large surface of the fluid to the action of the air, assisting
the spontaneous evaporation by any of the means at present employed for that
purpose. The fluid may, however, be concentrated by evaporation in pans
heated by a water bath or by steam, or indeed by any other plan either in the
-open air or vacuo, until it reaches a density while hot of about 25° Beaumé; it'
must then be filtered a second time, and afterwards brought up to the degree
of concentration which will permit of the rapid crystallization of the sugar, or,
if it be preferred, the crystallization may be carried on more slowly. The sugar
will be found in this operation to be free from the coloring matter usually
formed during evaporation, and fermentation will be entirely prevented if the
bisulphite of lime be added in such proportion that a small quantity of that
compound remains in the fluid unchanged up to the termination of the process.
Thus by the employment of bisulphite of lime and simple filtrations, to
separate the matters held in suspension, the whole of the crystallizable sugar
may be separated by one process from the expressed juice. The use of the
bisulphite of lime.or of the acid bisulphites in general may be made avail-
able both-when-the_sugar is obtained from the cane by simple mechanical
means only, and when a further process is resorted-to-for_the_extraction of that
portion of saccharine matter which is left in the cane refuse after the action of
the mill; that is to say, when the solid cane refuse is subjected to repeated
washings for the purpose of obtaining the last portions of saccharine matter
which mechanical pressure alone could not remove; in that case, by the use of
the bisulphite the whole of the crystallizable sugar can be obtained, no matter
how large the quantity of water employed, without loss from fermentation. All

page_text: the acid sulphites may be employed as above; and neutral, salts are also
capable of producing similar effects, provided they be soluble in sulphurous
acid, and provided also that the acid set at liberty can exercise no destructive
action upon the sugar in the solution; thus the neutral phosphate of lime
dissolved in sulphurous acid may be used for the complete extraction of the
crystallizable sugar, the phosphate of lime being obtained from bones in their
natural state, from calcined bones, or from bone charcoal, which may be used
in the same liquid.. Mustard, creosote, horseradish, nitrous acid gas either
alone or in combination with salts of iron or other salts, tannin, lamp black
saturated with creosote, the products of the distillation of certain bituminuous
matters, tars, or wood essence of turpentine, aldehyde and analogous bodies,
chlorine, either in the gaseous state or in solution, or in combination with
oxygen, may all be employed as antiseptics in the extraction of sugar from the
saccharine fluid, as in the process in which the bisulphite of lime is employed
alone. The operation ought to be conducted in such a manner that to the
mother liquors more or less rich in crystallizable sugar may be added the
saccharine liquors from the scum arising in the process of defecation, the
drainings of filters, washings of apparatus, molasses, &c. This method of
working, by which all the waste matters containing sugar may be turned to
profit, is impracticable under the old plan, but may be used advantageously
when the bisulphite of lime or other antiseptic agent is employed.
PART SECOND. SEPARATION OF THE CRYSTALLIZABLE SUGAR FROM SACCHARINE
FLUIDS IN COMBINATION WITH BARYTA, STRONTIA, LIME, OR OTHER
METALLIC OXIDES.
First, the hydrate of baryta added in proper quantity to molasses produces
the following result:-The baryta enters into combination with the sugar,
forming an insoluble saccharate of baryta, which, when washed with water,
may be regarded as a pure substance, uncontaminated by admixture with any
foreign matter.
Second, in like manner, when baryta is applied to the expressed juice of the
sugar cane or beet root previously defecated by means of lime, the saccharine
principle will be separated in an insoluble form in combination with the
baryta, and as much as ninety-seven per cent. of the whole quantity of
crystallizable sugar present in the fluid may thus be isolated, three per cent.
only remaining in solution combined with a further portion of baryta.
Third, the saccharate of baryta produced as above, when treated by any acid
which forms an insoluble salt with baryta, such as carbonic acid, sulphurous acid,

page_text: or sulphuric acid, furnishes crystallizable sugar' in the state of solution, perfectly
pure, and capable of producing refined sugar without any further preparation.
Fourth, cane juice or molasses diluted with water, and treated in the cold
state with an excess of lime, forms with the latter a soluble saccharate, the
composition of which appears to vary according to the density of the sacchia-
rine fluid at the time of mixing it with the lime by boiling. The soluble
saccharate of lime is converted wholly or in part into an insoluble saccharate,
'which is; however, only stable whilst the fluid remains hot..
.
Fifth, the oxide of strontium, and the protoxide of lead, also precipitate
crystallizable sugar from its solution. The first of these requires, however, to
be employed in great excess, and the second must be kept in contact with the
saccharine matter during a very considerable time; and even after all effects
the separation of the sugar but imperfectly.
Separation of Crystallizable Sugar by Baryta. In applying this process to
the juice of the cane, the latter must be first subjected to a defecation with
lime, without regard to whether it has been previously treated either with
lime, or with the acid sulphite of lime. The juice thus depurated is
transferred while hot to a boiler similar to that in which the defecation was
carried on. Baryta previously brought to the state of hydrate is now added to
the saccharine liquid in the proportion of fifty or sixty parts of caustic baryta to
every one hundred parts of crystallizable sugar contained in the fluid; the mix-
ture is strongly agitated to promote the solution of the baryta; it is then brought
up to the boiling point, when a precipitate of saccharate of baryta begins to be
formed, and after a few minutes of ebullition the reaction between the sugar
and baryta will be complete. The liquid is now left at rest, in order that the
precipitate may subside. The mother liquor containing the excess of baryta
in solution may 'then be drawn off, and the precipitate completely separated
from the fluid 'either by the press, by the apparatus of displacement, or, better
still, by the centrifugal apparatus at present in use for the defecation of sugar.
The washed and prepared saccharate contains, according to the degree of
pressure to which it has been subjected, about fifty per cent. of sugar, twenty-
two per cent of baryta, and twenty-eight per cent. of water. By treating the
saccharate of 'baryta with water acidulated with sulphuric acid, the baryta
separates in the form of the insoluble' sulphate, and the. sugar is set at liberty
in the fluid as a sirup more or less concentrated, twenty-five quarts of water
and twenty-eight pounds of sulphuric acid (sixty-six degrees Beaumé), give
a mixture of the most convenient strength for the decomposition of the
'saccharate of baryta, constituted as described above; in adding the 'diluted

page_text: acid to the saccharate a small quantity only must be poured in at a time, to
prevent the presence of free sulphuric acid, which would act injuriously on the
sugar. The addition of the acid must also take place in the cold, it is there-
fore desirable that the dilute acid be added in small consecutive portions to the
whole of the saccharate, the mass being stirred to favor the chemical action of
the acid upon the baryta. When all the saccharate of baryta is believed to be
decomposed a slight excess of sulphuric acid may be added, so as to completely
ensure the decomposition of the whole of the saccharate; the mixture may then
be pressed without loss of time, to separate the syrup from the insoluble baryta
compound, as the mixture ought never to be left for any length of time when
free acid is present; if circumstances prevent the immediate treatment of the
mixture for the separation of the syrup, it ought to be left with an alkaline
reaction. The acid syrup separated by the press from the sulphate of baryta
must be neutralized by the addition of a little more of the saccharate, and by
treating the fluid with a little sulphate of lime the ultimate removal of
whatever excess of baryta may be present will be effected. The precipitate of
sulphate of baryta may be subjected to repeated washing and pressing, to
remove the whole of the syrup, and it may conveniently be deprived of every
portion of saccharine matter by the means described for cleansing the
saccharate itself. By following the above-described process a syrup may be
obtained of a density of fifteen degrees to twenty degrees Beaumé, and which
may be at once submitted to the ordinary process of refining, furnishing a
sugar of great purity, proper for commercial purposes. To apply this process
conveniently to the molasses of commerce, it will be necessary to bring the
fluid in the first instance to a density of twenty degrees, or twenty-five degrees
Beaumé. If the liquid be prepared from molasses, which contains uncrystal-
lizable sugar, a quantity of lime is first boiled with the liquid, in the proportion
of one part of lime to four parts of the uncrystallizable sugar found to exist in
the solution. After boiling with the lime, the treatment with baryta, according
to the description already given, is put into operation, the baryta added to the
one hundred
solution being in the proportion of fifty or sixty parts to every.
parts of crystallizable sugar. The baryta used for this purpose ought to be in
the state of bydrate mixed and boiled with water, and the saccharine fluid
should also be boiled and well stirred after the addition of the baryta, to
promote the formation of the saccharate. The separation of the mother
liquors from the precipitate may be effected in the manner already described.
The mother liquor and the washings will serve economically to dilute a further
quantity of molasses, so as to bring it to the degree of density most proper for
the action of baryta upon the saccharine principle. In the process just now
:

page_text: described the caustic baryta, or its hydrate, may be substituted by sulphuret of
barium, a compound of which the formation precedes that of the caustic baryta
in the reproduction of the latter substance from the sulphate. When the
sulphuret of barium is employed copper vessels ought not to be used. The
different operations should be performed in vessels of wood, or in those of zinc
or cast iron, neither of which metals are sensibly attacked by the sulphur. In
that part of the process which relates to the decomposition of the saccharate of
baryta by sulphuric acid, a modification of the process may be employed.
Instead of using sulphuric acid, an equivalent quantity of sulphate of lime may
be added to the saccharate; the result would be the formation by double
decomposition of an insoluble sulphate of baryta and a saccharate of lime,
extremely soluble in the cold. By employing a slight excess of sulphate of
lime, the complete decomposition of the saccharate of baryta may be insured.
The saccharate of lime held in solution may be decomposed by sulphuric acid,
sulphurous acid, or carbonic acid, either of which will separate the lime in an
insoluble form, and a solution of syrup will be.thus obtained sufficiently pure
to furnish refined sugar of first rate quality. If carbonic acid be used to
remove the lime this gas may be obtained by any of the ordinary means; by
the combustion of carbon, for instance, by the calcination of limestone in a
close chamber, by the decomposition of alkaline carbonates, and more
especially by the action of hydrochloric or sulphuric acid upon chalk. The
saccharate of baryta suspended in water may be decomposed by passing
through the fluid a current of sulphurous acid gas. The baryta is then
separated in the state of insoluble sulphite. The sulphurous acid employed in
this operation may be obtained by the combustion of sulphur or of a sulphuret,
or by roasting the precipitate of sulphur and hyposulphite of baryta obtained
by treating with sulphurous acid the mother liquor from the precipitate formed
when sulphuret of barium is added to the saccharine solution.
Separation of Crystallizable Sugar in combination with Lime.-The cane
juice employed in this process must be first defecated with lime, then cooled down
to fifty degrees Centigrade, then again treated by lime in the proportion of
twenty-five parts of the hydrate of lime to every one hundred parts of crystal-
lizable sugar contained in the fluid. Thus a fluid containing twenty-two
pounds of sugar will require about six pounds of hydrate of lime; the
mixture is then heated to ebullition, the saccharate of lime, which is
insoluble at the boiling point of water, is then separated by filtration,
employing the kind of filter known as Taylor's filter. This separation may
likewise be effected by means of a press, contrived so that it may be kept heated
to one hundred degrees by steam. The saccharate of lime obtained by this first

page_text: separation contains, if the operation has been well conducted, about fifty-eight
The saccharate
per cent. of the sugar which was present in the liquid.
consists of five equivalents of base to one of saccharic acid. The mother
liquor obtained in this operation is cooled artificially, or permitted to cool
spontaneously. It is then again treated with lime in the proportion of from
three to four pounds to every twenty-five gallons of fluid. The mixture is
boiled to precipitate the saccharate, which becomes insoluble at one hundred
degrees, and the separation is effected by the means just now described. When
cane juice is thus treated it will be necessary to repeat the operation at least
four times; generally it may be said that the treatment ought to be repeated
more or less frequently according to the density of the saccharine fluid, and to
the degree of exhaustion which is desired to be produced without concentrating
the fluid. The different portions of saccharate produced in the above process
are mixed together in water, and treated with any acid which, like carbonic
acid or sulphurous acid, will form with the lime an insoluble compound. The
saccharine matter is thus separated from the lime in the form of syrup, ready
at once to furnish, by the usual treatment, refined sugar fit for commercial
purposes.
Separation of the Crystallizable Sugar by Strontia.-What was said, in
describing the process of separating the sugar by means of baryta, is applicable
in every respect to the employment of strontia. The latter is, however, inferior
to baryta; firstly, on account of the large quantity required to produce an
equal effect; and, secondly, from the circumstance of the saccharate of strontia
being soluble in pure water.
Separation of Crystallizable Sugar by Oxide of Lead.-When oxide of lead
is employed for this purpose it requires to be kept for a considerable time in
contact with the juice, in order to produce the precipitation of the sugar.
What has been already said of the decomposition of saccharate of baryta by
carbonic acid, applies equally to the oxide of lead. To complete this explana-
tion it ought perhaps to be added, that the various processes above described,
in reference to cane juice, can be employed with equal success in separating
the crystallizable saccharine principle from any other vegetable sap. It should
further be said, that the new methods which constitute the present Invention
may be employed either alone, combined with each other, or with any of the
old methods of working. Thus the sugar refiner may apply these processes to
raw sugar, to molasses, or to syrups in any stage of the manufacture. He may
employ the old plan for the first workings of his sugar, and apply the new
process only for the syrups in the second and third workings, or only to the
molasses. The planter may, after having exhausted the canes by the ordinary

page_text: process, obtain a still further quantity of saccharine matter from the cane refuse
by washings' with hot or cold water. These defecated washings may be
deprived of the whole of their sugar by the precipitating agents employed in
the new processes, or they may serve to dilute the molasses which is intended
to be subjected to treatment by baryta. Sugars obtained by the ordinary
means, containing much color, may be easily separated from their molasses by
the methods of Howard or. Schatzenbach, and, after being cleared and
decolorized, their molasses may be advantageously subjected to the treatment
with baryta.
Production and Restoration or Reproduction of the Baryta employed in the
Manufacture of Sugar by the New Process.-Any one of the known processes
may be employed in the production or regeneration of the hydrate of baryta
as the basis of the operations; the sulphate of baryta is, however, preferred,
as that is a substance found abundantly in nature, and obtainable at a very
low price; but the carbonate or sulphite of baryta may perhaps be employed
with equal advantage. Whatever may be the process employed, the first step
consists in procuring the baryta in the required state. The saccharate of
baryta will then be formed by the action of the baryta on the cane juice or
molasses. The saccharate is decomposed by passing a current of carbonic
acid into the fluid, holding the saccharate in suspension. The carbonate of
baryta.may be decomposed at a high temperature in an earthern retort or
reverberatory furnace, under the influence of a current of superheated steam,
or the carbonate may be mixed with fifteen or twenty per cent. of coal, and
heated either with or without the introduction of steam; or the carbonate may
be decomposed by means of nitric acid, and the liberated carbonic acid gas
may then be employed to decompose a fresh portion of the saccharate of
baryta.
The following is the mode of operating when sulphate of baryta is used:-
The sulphate of baryta in powder, as it is found in commerce, is mixed
intimately with forty-five per cent. of its weight of ground coal, and the mix-
ture is calcined at a high temperature in a reverberatory furnace. When the
sulphuration, or rather deoxidation, is complete, the charge is withdrawn from
the furnace and suffered to cool without exposure to air. .The mixture is
afterwards dissolved in water, in which it is very soluble. The insoluble
residue, if there be any, must consist of undecomposed sulphate of baryta ;
this may be added to a further quantity of sulphate, and submitted to the
action of the furnace as before. If the sulphite of baryta be employed as the
source of sulphuret of barium, it must be treated precisely in the same manner
as the sulphate, in a reverberatory furnace. The result of the operation is the

page_text: same, (videlicet) the production of sulphuret of barium; but in the case of
the sulphite less carbon is necessary to effect the reduction than when the
sulphate is employed. The solution of sulphuret of barium, prepared as above,
may be applied at once in the treatment of a solution of sugar, according to
the process described in a former part of this Specification.
To produce caustic baryta from the sulphuret of barium, in addition to the
process by which the sulphuret is converted into nitrate, there are two other
methods which may be preferred. Among metallic oxides, the hydrated pro-
toxides of zinc and of iron produce this transformation; but the oxide of copper
is preferable, both with respect to economy and to the effect it produces on the
compound of baryta. The oxide of copper, added in equivalent quantity to the
sulphuret of barium, passes into the state of insoluble sulphuret of copper,
depriving the barium of the sulphur previously combined with it, and leaving it
in solution as caustic baryta; this solution may be employed at once for the
precipitation of the sugar, or the baryta may be separated from the solution by
crystallization as hydrate of baryta. The sulphuret of copper produced in this
operation is reduced again to the state of oxide, by being roasted in a reverbe-
ratory furnace, and the sulphurous acid generated may be advantageously
employed when the acid sulphites are used in the separation of the saccharine
matters. The solution of the sulphuret of barium, when concentrated to the
proper point, gives rise to an abundant crystallization. The crystalline mass,
which consists of sulphuret of barium, is next exposed to the influence of the
atmosphere (free from carbonic acid), the sulphuret becomes oxidized, and con-
verted into half an equivalent of baryta and half an equivalent of hyposulphite
5 of baryta, the latter is insoluble, and is separated by washings with hot water.
PART THIRD. THE CLEANSING OR PURIFICATION OF THE SACCHARINE JUICE BY
THE EMPLOYMENT OF CERTAIN DEFICATING COMPOUNDS.
The bisulphite of lime, and the bisulphites or acid sulphites in general, may
be employed as a 'means of defecating or purifying the juice of the cane, or
0 other vegetable juices containing saccharine matter, permitting, consequently,
of the extraction of the sugar without the intervention of any other agents.
The defecating operation may be performed in the following manner :-The
liquid expressed from the cane is first submitted to certain mechanical opera-
tions for the purpose of removing solid impurities. A solution of bisulphite of
5 lime, equal to ten degrees Beaumé, is then added, in the proportion of one per
cent. of the original weight of the cane; an excess of this solution, however,
.does not produce any injurious effect, and the quantity may be increased to ten
per cent. of the weight of the cane, without causing any loss of sugar or other
mishap. After the treatment by the bisulphite of lime, if heat be applied to

page_text: the solution a portion of the bisulphite is converted into the neutral sulphite,
which precipitates, coagulating and carrying down with it the albuminous
inatters contained in the solution. The mixture must now be allowed to
remain at rest, in order that the solid matter may subside, the liquid is then
drawn off, and completely separated from every portion of the precipitate by
filtration. The fluid may now be concentrated by evaporation, exactly in the
manner and with the precautions described in the first part of this Specifica-
tion, and the saccharine principle may be obtained from the fluid by
crystallization. The whole of this treatment closely resembles that employed
when the bisulphites or acid sulphites are used only as a means of preventing
fermentation in the saccharine fluid, and which has already been described in
detail.
:
All the acid sulphites or bisulphites may be employed in the defecation of
the cane juice or other saccharine fluid; as may also those neutral salts which
are soluble in sulphurous acid, provided the displaced acid cannot react
injuriously on the crystallizable sugar.
By means of these processes the whole of the sugar contained in the cane
juice may be obtained in a state of purity; and, by the employment of the
precipitating agents described above, the sugar held back by the liquors may
be entirely separated. This gives great value to that part of the Invention
which relates to the preservation of saccharine fluids from undergoing fermenta-
tion, by which a portion of the crystallizable sugar would be lost. The planter
ought in the first place to direct his attention particularly to the process of
preservation from fermentation by the bisulphite of lime, for the application
of the precipitating agents destroys the uncrystallizable sugar, which forms a
colored compound with the lime, and operates injuriously in the process for
cleansing the insoluble saccharates..
The alkaline state being desirable in the manufacture of sugar, it is strongly
recommended, where the bisulphite of lime or other antiseptic agents are not
employed, to render the solution alkaline by means of lime, added with great
care, either at the rasping machine or at the crushing mill.
Having now described the Invention as communicated to me by my foreign
correspondent, I wish it to be understood that, under the above in part recited
Letters Patent, I claim,-
First, the use of bisulphites or acid sulphites (particularly the acid sulphite
of lime) as preservative agents against fermentation, and as depurators of
vegetable juices containing crystallizable sugar.
Second, the use of the various antiseptic substances herein-before mentioned,
as employed as preventatives to fermentation in saccharine fluids.
Third, the employment of baryta, strontia, and of the sulphurets of barium 4