IMPROVEMENTS IN THE MANUFACTURE AND REFINING OF SUGAR
Year: 1847

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
SCOFFERN, of Upper Holloway, M.B., send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of
Great Britain and Ireland, bearing date at Westminster, the Eighth day of
December, One thousand eight hundred and forty-seven, in the eleventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Scoffern, my exors, admors, and assigns, Her especial
licence, full power, sole privilege and authority, that I, the said John
Scoffern, my exors, admors, and assigns, or such others as I, the said John
Scoffern, my exors, admors, 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 expressed, should and lawfully might make, use, exercise, and vend,
within England, Wales, and the Town of Berwick-upon-Tweed, in the Islands
of Jersey, Guernsey, Alderney, Sark, and Man, and also in all Her said
Majesty's Colonies and Plantations abroad, my Invention of "IMPROVEMENTS
IN THE MANUFACTURE AND REFINING OF SUGAR;" in which said Letters Patent
is contained a proviso, that I, the said John Scoffern, should cause a particular
description of the nature of my said Invention, and in what manner the same
is to be performed, by an instrument in writing under my hand and seal, to
be inrolled in Her Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said in part recited

page_text: Letters Patent, as in and by the same, reference being thereunto had, will
more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Scoffern, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, that is to say :-
My Invention consists of the employment of sulphurous acid as a means of
separating lead used for purifying or removing coloring and other foreign
matters from solutions containing sugar.
And in order that my Invention may be most fully understood, and readily
carried into effect, I will proceed to describe the means pursued by me. I
would, however, first state that it has before been proposed to apply salts of
lead as a means of purifying sugar in the course of manufacturing and refining
the same, but heretofore no practically useful means of separating the lead
therefrom has been employed. For convenience of arrangement I will treat
my Invention under two heads:-
First, as applied to the process of sugar refining.
Second, as applied to the process of extracting sugar from the original
juice, whether of the cane, beet-root, or other material from which the kind of
sugar termed by chemists "cane sugar" may be procured.
The object which the sugar refiner has in view is the separation from his
raw material of every impurity, so far as may be practicable; and although
the various stages of sugar refining are modified to suit the judgment and
to accord with the convictions of different manufacturers, yet the following
general principles I believe are embraced by all:-First, the process of
blowing up. Second, the process of filtration (first, through fibrous textures;
secondly, through deep beds of animal charcoal in the granular state). Third,
the process of boiling (generally in vacuo). Fourth, the process of claying
(technically so called, although clay is now no longer used). Fifth, the
process of liquoring. Sixth, the process of drying and stoving.
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Adaptation of my Invention to Refineries.-Having put the quantity of
sugar to be operated upon into the blow up pan, and having dissolved it in
the ordinary way, omitting, however, the usual addition of lime water and
spice" (blood), I add the lead material (prepared as herein-after indicated
and in the quantity herein-after indicated), such lead agent having been first
rubbed up with enough of hot water or syrup to make a thin magma or paste.
It is desirable in all cases to add enough and not too much of the lead agent;
and I find that a certain amount of experience is necessary to enable the manu-
facturer to determine how much of the lead agent any particular sample of

page_text: sugar may require; I can for that reason only give general directions.
Supposing the sugar intended to be operated upon be an average refining
sample of Jamaica produce, the manufacturer should commence his operations
by using the proportions of forty grains of the lead material obtained by the
process to be hereafter mentioned to every pound of sugar, less pure sugar
requiring more material. By proceeding thus he should obtain a good result,
and the information he acquires by this operation will be a sort of standard
for the future. A portion of the sugar, thus operated on, should be set apart
for future reference, until the manufacturer shall have trained his eye suffi-
ciently to appreciate the relation between the character of certain sugars and
the corresponding amount of material necessary to separate their impurities.
I would observe that any quantity of the lead material which the manufacturer
might choose to add may be effectually separated by my process.
Having added the determined quantity of lead material, I heat the liquid
to the temperature of about one hundred and eighty degrees Fahrenheit.
After the sugar has been perfectly dissolved and the lead material well
incorporated, the application of heat to the degree last-mentioned during the
space of five minutes is all that I have found necessary to produce the desired
effect. After this I allow the contents of the vessel to repose for the space
of about fifteen minutes, when, on examining the surface a curdy brown
precipitate may be seen gradually sinking to the bottom, leaving the liquor
above in a greater or less degree of transparency; I then resort to the process
of bag filtration.
The liquor which comes through the filter apparatus is to be received into
a copper vessel, and it will be found to contain a considerable portion of lead,
which is to be separated by the operation which I call "gasing," and which
consists in passing through it streams of sulphurous acid gas, until a portion
of the liquor properly tested shall yield no trace of lead. To accomplish this
end I observe the following plan:-Supposing the liquor to be operated on to
result from the solution of two parts of sugar and one of water; it will be
viscous or like a syrup; the liquor in this state is to be agitated during the
application of the gas.
After the gas has been transmitted for about ten minutes, the liquid should
be tested to see whether it contains lead in solution.
By the side of the operator should be conveniently placed two or three.
filters of filtering paper, each about four inches diameter in the round (that is
to say, before being folded into a conical shape), a bottle containing hydro-
sulphate of ammonia (the kind of hydro-sulphate of ammonia I employ is
made by transmitting a current of hydro-sulphuric acid gas through an

page_text: aqueous solution of ammonia), or an aqueous solution of hydro-sulphuric acid,
a few clean straws, a solution of sugar of lead (twenty grains to the fluid ounce
of distilled water), some filter supports, test glasses, a mixture of one ounce of
chalk with three ounces of water, and a Berlin-ware boiling dish. To ascer-
tain if any lead be left proceed as follows:-Into a Berlin boiling dish put
about a fluid ounce of the liquor, give it a boil over a spirit lamp, add a tea-
spoonful of the chalk mixture, boil again for a minute, then pour the boiled
liquid on a filter previously made wet with water. The liquid will at first
come through so turbid that to test it would be difficult, therefore it should be
passed through the same filter at least twice; still it will seldom be quite clear
at this stage on account of the density of the liquor; with weak liquors the
case is different. This ultimate want of clearness, however, interferes in no way
with the perfect action of the test to be applied, which is done as follows:-
Into the filtered liquid or a portion of it pour about ten drops to the ounce of
bydro-sulphate of ammonia (should that test be employed), or about a fourth
part of the filtered liquid's own volume of hydro-sulphuric acid solution (should
that test be used), and observe the appearances that result. Should the
addition of either test occasion the least tint of blackness, it is a sign that
the liquor still contains lead, and that it must be further "gased." Should the
result however be that the addition of the test produces no visible effect or
merely a whiteness, it may be concluded that the "gasing" has been continued
long enough. It is desirable to proceed a step farther in the process of testing,
and for this purpose I use the solution of sugar of lead as a counter-test, thus,
taking the portion of filtered liquid to which the test has been added, with no
visible effect, or with merely the production of a whiteness, I now drop in by
means of a straw (note, straws should never be used a second time) a small
quantity of sugar of lead solution, when, supposing all conditions to have been
effective, a patch of blackness will be observed, and which may be permanent or
may presently change to white or grey. The appearances here indicated (if
observed on the addition of the counter-test) assure the operator most confidently
that all lead had been previously removed. He therefore proceeds with the next
part of his operation. By means of any convenient source of heat (steam in pre-
ference), the liquor which has been gased is heated with all convenient rapidity
to a temperature of 180° Fahrenheit; chalk, or powdered marble, or other
convenient form of carbonate of lime is then to be added, in weight equal by
preference to one-sixth of the lead material originally employed. To facilitate
the admixture of the chalk, or other carbonate with the fluid, either of them
should be added in the condition of thin paste, made by rubbing it up with
water. Having added the chalk, it is advisable to retain the liquor at a

page_text: temperature of 180° Fahrenheit, or thereabouts, for about ten minutes or a
quarter of an hour. Note.-In operating upon a liquor of the density of two
of sugar, and one of water or thereabouts, I assume that animal charcoal is to
be employed as the last filtering agent, for otherwise it would be preferable to
operate upon solutions of less density. The liquor is now in a condition to
be filtered previously to its being turned on to the charcoal beds. In applying
my Invention to cane juice, I find it desirable to render the juice neutral or
slightly alkaline before treating it with the lead material. I, therefore, first
test the juice by litmus paper, and if the color of the paper is changed by acid
or acid salts I proceed to neutralize the same by lime or chalk (if chalk be
used I first make it into a paste by grinding it with water; if lime be
employed, what is called cream of lime is to be used), and having heated the
juice to about 180° of Fahrenheit, if I employ chalk, I stir in small quan-
tities, till the juice no longer indicates the presence of acid, or only very
slightly so; if I employ lime, then I carry on the process till slight but
distinct alkaline reaction is indicated to the test. I now apply the lead material
in the manner above described, but in the proportion of one hundred and fifty
grains to each imperial gallon of the juice, but such proportion will be varied
according to the purity or density of the juice. The liquor is next to be filtered,
gased as above explained, and subjected to the action of carbonate of lime, so
as to neutralize all acid, as in the previous case. If my Invention be applied
to beet root or other juice, I operate on the same after it has been treated
with lime, as at present practised, and then it is to be operated on by the lead
material as described in respect to the cane juice, but larger quantities of the
lead material are required.
I will now explain how I prepare the lead material I prefer to use in
carrying out my Invention. Take twelve gallons or any proportionate quantity
of vinegar, of five per cent. strength, heated in a copper vessel to one hundred
and sixty degrees Fahrenheit; then gradually pour in (stirring all the time)
forty pounds avoirdupois of finely powdered litharge; now raise the temperature
until the mass boils, frequently dislodging or breaking the crust which collects
upon the bottom of the vessel; ebullition may be continued until the mass
becomes so thick that portions are blown out of the vessel by the process of
boiling, at which period the heat should be gradually decreased, and the last
5 portions of moisture should be dissipated by a gentle heat. If vinegar of
greater strength be used a proportionably greater quantity of litharge is used;
the result thus obtained I consider to be a mixture of two or more of the basic
acetates of lead, of which chemists recognize several. The above is a cheap
mode of preparing the lead material for my Invention. I do not, however,

page_text: claim such preparation, nor do I confine myself thereto. I would state that
sulphurous acid, combined with a base such as magnesia, or otherwise, may
be employed for separating lead from sugar in solution. But I believe not
with such advantage as results from the means above explained.
Having thus described the nature of my Invention, and the manner in
which the same is to be performed, I would remark that I do not confine
myself to the precise details, so long as the peculiar character of my Inven-
tion be retained. But what I claim is the combined use of sulphurous acid
with lead in the manufacturing and refining of sugar.
In witness whereof, I, the said John Scoffern, have hereunto set my 1
hand and seal, this Eighth day of June, in the year of our Lord One
thousand eight hundred and forty-eight.
Enrolled the Eighth day of June, in the year of our Lord One thousand
eight hundred and forty-eight.