IMPROVEMENTS IN THE MANUFACTURE OF SUGAR
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
MATHISON FRASER, of Mark Lane, in the City of London, Merchant, send
greeting.
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-seventh day of December, in the fourteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Mathison Fraser, Her especial license, full power, sole privilege
and authority, that I, the said John Mathison Fraser, my exors, adñññors, and
assigns, and such others as I, the said John Mathison Fraser, my exors,
adiñiors, 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 THE MANUFACTURE OF SUGAR,"
being a communication from a foreigner residing abroad; in which said
Letters Patent is contained a proviso, obliging me, the said John Mathison
Fraser, 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 had, will more fully and at large
appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Mathison Fraser, do hereby declare that the nature of the said Invention,
and the manner in which the same is to be performed, is particularly described
and ascertained in and by the following description thereof, reference being
had to the Drawings hereunto annexed, and to the letters and figures marked
thereon (that is to say):-
This Invention of improvements in the manufacture of sugar, as communi-
cated to me by my foreign correspondent, consists in the addition, in the first
instance, of a certain quantity of lime to the expressed juice of the sugar cane
or beet-root, at the time and in the manner herein-after mentioned, and in the
subsequent addition of a certain proportion of an aqueous solution of
sulphurous acid, which acid may be prepared or obtained in various ways,
either by the direct combustion of sulphur in the atmosphere, or by heating
mixtures of certain metallic oxides and sulphur, such as the oxide of manga-
nese, or by decomposing sulphuric acid by the action of certain metals aided by
heat, as copper or mercury; or sulphuric acid may be decomposed by means of
certain carbonaceous substances or charcoal, and it is the latter process which
it has been found most convenient to employ, and which is conducted as
follows: The apparatus consists of threo vessels, which for distinction sake I
shall call the generating vessel, the washing vessel, and the saturating vessel.
These vessels may be made of glass or earthenware, or glazed or enamelled
iron, or of lead, and in some cases cast iron may be used, more especially for
the generating and washing vessels. These vessels are connected with each
other by means of tubes or pipes of any proper and convenient material, as
represented in the annexed Drawing, where A represents the generating
vessel; B, the washing vessel; and C, the saturating vessel. The materials
furnishing the sulphurous acid are placed in the vessel A. For this purpose
one part by weight of coarsely pulverized wood charcoal, imbued with eight
parts by weight of common sulphuric acid or oil of vitriol of commerce, is
generally employed, and to the vessel containing these materials heat is
applied, so as to raise them to such a temperature as to occasion the regular
and moderately rapid generation of sulphurous acid gas, which, together with
the carbonic acid gas at the same time evolved, passes through the connecting
pipe D into the washing vessel B, and bubbling through the small quantity of
water contained in that vessel, passes through the tube E into the saturated
vessel C, which contains a sufficient quantity of cold water to absorb the
sulphurous acid, so as to form a saturated aqueous solution of that acid, whilst
the carbonic acid gas escapes into the atmosphere; the neck or opening of the

page_text: saturating vessel C not exactly fitting the tube E, but being large enough to
allow of the free escape of the unabsorbed gas.
This apparatus may be variously modified as to the form and arrangement
of the vessels; and the number of the saturating vessels may, if required, bo
increased, so that when the water in the first of them is saturated with the
acid, the gases may pass into a second saturating vessel, and so on, in the
manner frequently practised in chemical works, where water or other liquors
are to be saturated with gases, forming a modification of what is known to
chemists under the name of Woolfe's apparatus. In this way a saturated
aqueous solution of sulphurous acid is obtained, such solution smelling strongly
of the gas, first reddening and afterwards bleaching litmus paper, and having a
specific gravity of about 105, and containing about thirty times its volume of
gaseous sulphurous acid. This is termed the sulphurous solution, and it is
either used at once or preserved in close vessels, or in well-corked or stoppered
bottles or carboys, as convenience may require.
I will now describe the further mode of proceeding when operating upon
cane juice, which is expressed between cylinders in the usual manner, and
conducted by an open channel or gutter into a proper tank of wood, brick-
work, or other suitable material. At the extremity of the gutter a sieve or
strainer is suspended, and upon this sieve, which arrests a proportion of the
mechanical or suspended impurities of the juice, about 0.812 Netherland
pounds of quicklime are placed, then in a keg or other convenient vessel the
same quantity of fine quicklime is mixed with four Netherland cans (about
seven-eighths of an imperial gallon) of cane juice, or a sufficient quantity to
make a mixturo of the appearance of cream, and such mixture is added to
each thousand Netherland cans (about two hundred and twenty gallons) of the
cane juice in the tank, with continuous stirring whilst the juice is running
into the tank. But as soon as the tank is about half full, containing, namely,
about five hundred cans, or one hundred and ten gallons, there must be added
three cans of the above-described sulphurous solution, and the whole well
blended by means of a wooden stirrer, and afterwards, while the tank is
becoming full, another can of the sulphurous solution must be poured in, and
the whole carefully and completely mixed together by means of the stirrer;
the contents of the tank are then left for about one hour, so as to subside or
settle, after which the liquor is drawn off from the sediment into the usual
pans employed for evaporation and boiling, particular attention being paid to
the skimming while that process is going on. Working in this way it will
be found that the cold liquor as it runs out of the tank is of a dark olive color,

page_text: but that in the process of evaporation it acquires a light green shade, evolving
at the same time a peculiar odour, and that dark colored flakes are thrown up
along with the scum; as the juice becomes hotter the depth of its color and
its peculiar odor gradually diminish, until at length it acquires a golden color,
and the flakes which are thrown up are pale yellow; these must be carefully
skimmed off till the liquor is perfectly clear, and it may then, without any
further additions, be at once evaporated into sugar and treated in the usual
way. Should the boiling off be performed in a vacuum pan instead of the
common boilers, the necessary cleansing of the juice, by skimming takes place,
perhaps sooner but not later than when it has acquired a density equal to
about 88° of Beamé's hydrometer, or about 1-3 specific gravity, some variations
in these respects arising out of the quality of the juice.
Having now described the improvements in the manufacture of sugar, as
communicated to me by my foreign correspondent, I wish it to be understood
that I do not claim the application of lime and sulphurous acid to cane or
beet-root juice, in whatever manner such application may be effected; but I
claim the treatment of such juices in the manner and for the purpose above
set forth.
In witness whereof, I, the said John Mathison Fraser, have hereunto set
my hand and seal, this Twenty-sixth day of June, in the year of our
Lord One thousand eight hundred and fifty-one