CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF SUGAR
Year: 1847

page_text: TO ALL TO WHOM THESE PRESENTS SHALL. COME, I, JAMES
JOHNSTON, of Willow Park, Greenock, Esquire, 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 twenty-seventh day of
May, One thousand eight hundred and forty-seven, in the tenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said James Johnston, my exors, .admors, and assigns, Her especial licence, full
power, sole privilege and authority, that I, the said James Johnston, my exors,
adñiors, and assigns, or such others as I the said James Johnston, my exors,
adiiors, or assigns, should at any time agree with, and no others, from time to
time and at all times, during the term of years herein expressed, should and
lawfully might, make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, and in the Islands of Guernsey, Jersey,
Alderney, Sark, and Man, and in all Her Majesty's Colonies and Plantations
abroad, my Invention of "CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF
SUGAR;" in which said Letters Patent is contained a proviso that I, the said
James Johnston, shall 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 said 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
James Johnston, do hereby declare that the nature of my said Invention, and
in what manner the same is to be performed, are fully described and ascer-
tained in and by the following description thereof, reference being had to
the Drawings hereunto annexed, and to the figures and letters marked
thereon (that is to say):-
Throughout Her Majesty's Dominions to which these Letters Patent extend
there are three kinds of sugar manufactories. First, in the colonies, the
manufacture of sugar consists in making sugar out of cane juice. Second,
the sugar houses in England in which raw sugar as it comes from the colonies
is refined and made into loaf sugar. Third, the sugar houses in England in
which molasses in the state in which they are imported from the colonies are
boiled up and converted into what is termed crushed sugar. This last kind
of sugar manufactories are commonly called molasses houses.
For simplicity and ease of description I make choice of a molasses houso 1
as my model in describing the following improvements in the various depart-
ments of sugar manufacturing.
The puncheons of molasses as brought from the colonies are emptied into
a large cistern, and the first process consists in medicating or doctoring them;
that is, lime water is added to the molasses in the cistern prior to their
being put into the vacuum pan to be boiled. This adding of alkali in the
shape of lime water to the molasses is necessary in most cases to check
asidity or fermentation in the molasses. The application of alkali to molasses,
or any other saccharine solution which is about to be boiled, is one of the most
difficult duties of the sugar refiner. If he does not put into the molasses a
sufficient amount of alkali to check the acidity or fermentation the product
of his boiling is injured, and if he puts in too much alkali the product is also
injured. The difficulty is to know what is the proper quantity of alkáli for
any given quantity and quality of molasses or saccharine fluid that requires to
be medicated. Chemists might possibly heretofore have decided this point
in a laboratory, but in the ordinary business of a sugar house no method has
yet been resorted to by which this has been accomplished on a large scale
with accuracy and speed. The present custom is for the man in charge to
throw into. the molasses according to his judgment (that is by chance) as many
buckets of lime water as he thinks proper, there is no test applied.
My first improvement in the manufacture of sugar is, for a means of testing
the proper quantity of alkali required for saccharine fluids whilst operating in
the ordinary business of sugar boiling. To revert to the operations in the
molasses house, after the molasses in the cistern have been medicated, they are

page_text: then put into the vacuum pan and evaporated till they are brought to the
crystallizing point. In this second or principal process of sugar manufacturing
I have some improvements to describe. The third process consists in putting
the boiled sugar into what are termed sugar moulds, and placing in a warm
room or loft in order to allow the treacle to drain out and leave the sugar in
the moulds in a dry state. In this department of sugar manufacturing I have
also improvements to describe.
The order of the processes, as above stated, are those of the first boiling in
a molasses house; the sugar in the state just described is called " bastard
sugar." Prior to the second boiling, or conversion of the sugar into the state
called "pieces," the process of filtering is introduced; but in it I have no
improvements to make, I therefore take no notice of it, but confine myself to
describing my improvements in the three processes of manufacturing sugar to
which I have referred, and they are as follows:-
First, the medicating of saccharine fluids.
Second, the evaporation of saccharine fluids, or bringing them to the crys-
tallizing point or proof.
Third, the potting or moulding of the sugar, and placing it in warm
lofts or rooms to drain.
:.
First Process, the Medicating of Saccharine Fluids.-This I accomplish
whilst saccharine fluids are flowing in thin strata along heated surfaces, such
as on inclined planes. I shall give some description of an inclined plane,
and also of an apparatus which I have invented to regulate the flow of
saccharine fluids when going on to inclined planes, as the successful applica-
tion of my mode of medicating saccharine fluids to some extent depends on
a steady current of liquid being obtained. See Figure 1st. A, A, is a cast-
iron table or inclined plane, so made that the steam can be admitted at B-to
heat it. Suppose this inclined plane to be twenty feet long and two feet wide,
provided with raised edgings, as seen at C, Figure 2, to prevent liquids running
off the plane at its sides. Apparatus of this kind for the evaporation of
saccharine fluids by making them run in thin strata from the high to the low
end of planes heated with steam are not new. The self-acting apparatus for
regulating the flow of saccharine fluids on these planes I shall now describe.
Figure 1st. D is a small cistern, it is a fixture; the frame or stand
which supports it is not shewn in the Drawing, as it would interfere with
the other parts of the apparatus. being understood. E is another cistern,
which is moveable, as it is suspended from the spring balance F, by the
framing G, G; in the bottom of the fixed cistern D there is a valve seat,
and suspended from the framing G, G, there is a valve H, which works

page_text: into the valve seat in the bottom of the cistern D. In one side of the sus-
pended moveable cistern E there is a narrow perpendicular slit J. The fixed
cistern is always kept full of the liquid to be boiled, it should communicate
with one of the ordinary cisterns in a sugar house. The mode of working.
the self-acting regulator is as follows:-When the valve H in the cistern D is
screwed up liquor runs down into the cistern E, and out at its outlet J, on to
the inclined plane. It must be borne in mind that the outlet J should be
made so narrow that when a good supply of liquor is running through the
valve the outlet J should not be able to let a corresponding quantity run
through it except there be a considerable rise or depth of liquid accumulating
in the cistern E; it is this rise of liquor in the cistern E, which sets the
machine in motion as a self-actor. The cistern E being suspended by a spring,
it is evident that the weight of the liquor in it will cause it to descend as the
spring will yield, but when the spring yields it brings down the valve H, so
that the supply of liquid to the cistern is checked. The stream of liquid
running through the apparatus will now be a steady uniform one, as the
slightest increase or diminution in the quantity of liquid running through the
suspended cistern E would act on the spring and consequently the valve H
would be opened or shut according to the increase or diminution of weight
indicated by the suspended cistern E. If any piece of extraneous matter in
the liquid should get into the valve II and interrupt the flow of the liquid
the cistern E would immediately become light, the spring would pull it and
the valve H up and the piece of dirt in the valve would get through. The
valve H and spring F are provided with adjusting screws, so that the quantity
of liquid can easily be regulated. This apparatus is useful for regulating the
flow of any kind of saccharine fluid on to inclined planes for boiling, but it is
chiefly useful for molasses or cane juice that has not been filtered. Self-acting
apparatus for regulating the flow of water and other liquids have long been
known and used, but a self-acting apparatus that will regulate the flow of
viscid or unfiltered saccharine fluids is new.
I claim the application of the above described or similarly constructed self-
acting apparatus to regulate the flow of saccharine fluids, or inclined planes,
or apparatus on which saccharine fluids are to be boiled or medicated.
Having described the method of obtaining a steady flow of saccharine fluid
over an inclined plane, I shall now explain 'how I medicate it. In Figure
1st the small cistern K, placed above the inclined plane, is filled with lime
water, and it is furnished with a stopcock and pipe L, which lets down the
lime water on to the inclined plane: The pipe L is provided with a cross
branch piece of pipe which extends the whole breadth of the plane, as seen

page_text: in Figure 2. It is pierced with small holes, so that the lime water falls in
a shower of drops or streams all the breadth of the plane. Now suppose that
acid molasses be made to run along the plane through the regulator, the
heat of the plane will immediately cause the molasses to ferment or froth up.
The cock L is now opened, and a shower of lime water allowed to fall on to
the plane. The molasses will now present the following appearance :-On the
short part of the plane, that is, between the regulator and the part where the.
lime water falls on it, the molasses will be in a state of foam, but immediately..
after passing the shower of lime water the foaming will cease, and the surface
of the molasses will present the ordinary appearance of boiling molasses.
To a practiced eye the difference is quite perceptible. In describing the effect
of the lime water, I have taken it for granted that the proper quantity. had
been let fall on the plane. If enough of lime water had not been let
fall, the foaming from fermentation would, not have entirely ceased. The
operator requires to attend that the quantity of lime water shall be suffi-
cient, but no more than sufficient, to check the fermented foaming on
the surface of the molasses.. I do not confine myself to the arrangement
of apparatus above described. The new method of medicating saccharine
fluids consists in making heat the test, and the mode of application which
I claim is the applying the proper quantity of alkali or medicating substance
in a liquid state while the saccharine fluid is running in a thin stream
over a heated surface, or to a thin stream of saccharine fluid in a heated
state, or to a stream of saccharine fluid to which heat is immediately to be
applied. ;
Second Process, the Evaperating of Saccharine Fluids.-The apparatus
most commonly used for this purpose is the vacuum pan. Fig. 3 is a
drawing of one of these pans, of the shape used by Mr. Howard, the patentee;
it consists of two hemispheres A & B bolted to each other by their flanches,
D is the plug hole at the bottom of the pan where the sugar falls out when
the pan is emptied, which is accomplished by first letting air in at a plug
hole C in the top of the pan. The other appurtenances of a vacuum pan are
not shewn in the Drawing, as they are not required for this description.
E, F, is a caldron into which the sugar falls when it comes out of the
vacuum pan and steam is admitted between its two bottoms at P. The use
of this steam caldron is as follows:-Sugar is boiled in vacuum pans, on
purpose that it may be done at a low temperature. Now it so happens that
the sugar in coming out of the vacuum pan is in; too cold a state for it to be
at once placed in the sugar moulds, the: temperature of it as it comes out
of the pan is generally about 145° or 150° Fah, and it requires to be about

page_text: ""
180 or 190 Fah before it is fit to be put into the moulds. For this reason
the sugar is kept heated in the steam caldron E, F, until it is raised to
the required temperature for being put into the moulds. This is the system
of working vacuum pans practised at the present date, viz', that of boiling
sugar at a low temperature in the vacuum pan; and then allowing its contents
to fall into a steam caldron, where it is heated under the influence of the
pressure of the atmosphere. During the last few years sugar refiners have
altered the original shape of vacuum pans by making an addition to them,
which addition they term à "crib." L, L, Fig. 4, is a view of a "crib," it is
placed between the original hemispheres A and B. These cribs allow great
space for the sugar to froath and boil up without boiling over. N, N, is
another addition to vacuum pans, invented and claimed under my Patent of
Thirty-first of January, One thousand eight hundred and forty-five. I call it a
"barometer pipe." The upper end of the pipe N opens into the lower
hemisphere B, and the sugar has free access into the pipe, so that the sugar
throughout the apparatus is in free communication with the vacuum above.
R is a cock for drawing off the sugar. The dimensions of the pipe shown
in the Drawing are 27 feet in-length and 4 inches of internal diameter.
The object of this addition to a vacuum pan is to obtain the advantage of
being able to remove the contents of a common pan without destroying
the vacuum. That is accomplished as follows:-The lower part of the pan
or pipe N, N, is made of such length that its contents balance the weight of
the atmosphere, and all the depth of sugar that is in the upper or globular
part of the pan is excess of weight over that of the atmosphere; therefore,
when the stopcock. R is open, all the sugar in the globular part of the pan
being excess of weight will run out through the pipe, but the pipe part
of the pan will remain full of sugar, as the pressure of the atmosphere
counterbalances it; such is the object' of the addition to vacuum pans. It is
a conversion of a vacuuin pan into a large barométer.
Since enrolling my former, Specification, I have found an advantage
beyond what I then described. is, obtained from. using a barometer vacuum
pan. I have already noticed the fact of common vacuum pans delivering
the sugar out of them at about a temperature of 145° or 150° Fahrenheit,
which is too cold for it being at once put into the sugar-moulds, as for that
purpose a temperature of 1800 or 190° Fahrenheit is required, and I find that
a barometer vacuum pan delivers the sugar out-of the required temperature
of 180 or 190° Fahrenheit; hence in addition to the advantage I originally
contemplated from my Invention, that of drawing the sugar from a vacuum
pan without destroying the 'vacuum, I find that the sugar may be at once

page_text: placed in moulds, thus saving the process of the steam caldron above men-
tioned. I will explain the cause of it. The boiling point or highest degree
of temperature, to which a liquid can be raised entirely depends on the amount
of pressure exerted on the liquid. The boiling point depends on the facility
of evaporation, and the evaporation depends on the pressure. The value of
common vacuum pans depends on the removal of the pressure of the atmo-
sphere and the .consequent boiling of the liquids within them at a low
temperature; and hence arises, also the disadvantage which accompanies their
use, viz, that the sugar on coming out of them is of too low a temperature to
be at once put into the moulds... In applying these remarks to the barometer
vacuum pan it, will be observed that, as in common vacuum pans, the sugar
is subject to a vacuum above and therefore it is boiled at a low temperature,
but the depth of sugar in the barometer vacuum pan is such as to create
a pressure that will tend to prevent evaporation in the pipe; conse-
quently I have in barometer. vacuum pans a peculiar advantage: that they
boil, the sugar at a low temperature in their upper part, and yet deliver it out
at. their lower extremity at a high temperature fit for its being at once
put into the moulds. I will further illustrate this subject by reference to the
pan Figure 5. It is in every respect the same as the pan Figure 4, except
that the pipe part of the pan is placed in a horizontal instead of a perpen-
dicular position, and it is provided with a plug Z like that in the bottom of
a. common vacuum pan. In all other respects the two pans, Figure 4 and
Owing to the pipe part of the plan Figure 5 being
placed in a horizontal position, the weight of the sugar in it will not be
sufficient to balance the weight of the atmosphere, consequently the sugar.
would not naturally run along the pipe and come out at the end P.; but, in
order to make the sugar, pass, along the pipe, let a pump V be. worked
at the end of the pipe so as to draw the sugar out and deliver it at the
valve Y.. Now suppose the two vacuum pans, Figures 4 and 5, to, be
worked with the same kind of sugar, the same pressure of steam, and the
same amount of vacuum in each pan (say by the barometer two inches of
mercury and corresponding temperature of 150° Fahrenheit) what would be
the temperature that each, of, these pans would deliver the sugar at their
respective outlets? As to the pan Figure 4, I have already shewn that
although the sugar in the upper part of it in contact with the vacuum is
at a low temperature, say 150°. Farenheit, in consequence of the freedom of
evaporation, yet at the stopcock Rit would deliver the sugar out at a
temperature between 180° or 190° Fahrenheit. But the pan Figure 5 will
Figure 5, are the same.
not operate, in a similar manner. If the sugar were removed out of it at the
'

page_text: plug Z, it is well known that it would be at the temperature of about 150°
Fahrenheit, in accordance with the state of the vacuum above referred to;
but instead of taking the sugar out at the plug Z, suppose it to be drawn
along the pipe part of the pan and delivered by the pump at the valve Y,
it would also be about 150° Fahrenheit, the same as if it came out at the
plug Z. The fact of the sugar being drawn along the pipe part of the pan,
which is subject to the heat of the steam as the other part of the pan, offers no
reason why the temperature of the sugar should be raised. Evaporation can
go on in the pipe part of the pan when placed in a horizontal position, as in
the bottom of the globular part of the pan, and that is the reason why the
temperature of the sugar is not raised while it is being drawn through the
pipe part of the pan. When the pipe is placed in a horizontal position it loses
all power of raising the temperature of the sugar, because there is no difference
of pressure at the plug Z and valve Y.
From what I have written on this subject it is evident that the two valuable
properties of barometer vacuum pans (their delivering the sugar out without
the vacuum having to be destroyed, and their delivering it out at a temperature
fit for its being at once put into the moulds) depends entirely on the depth of
sugar in these pans. I wish it to be distinctly understood that I make no
claim for the hot discharge when it is used or rather obtained in a pan along
with the other advantage, that is, the discharge without destroying the vacuum,
such being the result of working according to my former. Specification; but I
have found by using a similar tube to a vacuum pan not sufficiently long to
obtain the advantage of allowing a charge to be drawn without destroying the
vacuum, I can still obtain the other advantage of working a vacuum pan at
the ordinary low temperature, and yet deliver the sugar hot enough from the
pan by the tube to allow of its being at once conveyed to the moulds; and for
this purpose the tube shewn at Figure 1 would not require to be so long as
above described for maintaining a vacuum; but I prefer, under all circum-
stances, to obtain the two advantages above specified. I claim the use of a
descending tube applied to a vacuum pan, with the view of making the
pan capable of evaperating at ordinary low temperatures, and for delivering
the sugar out at a temperature sufficiently hot to avoid the at present common
practice of heating the sugar after it has come out of the pan, and prior to its
being put into the moulds, when such tube is not long enough to act as a
barometer pipe to maintain a vacuum in the pan when drawing a charge.
Having described the action and mode of working barometer vacuum pans,
I shall now proceed to describe my principal improvement under this head or
in the manufacture of sugar. Figure 7 is a plan of improved arrange-
process

page_text: ments of apparatus for evaporating saccharine fluids. It is a combination of
a vacuum pan and apparatus for boiling sugar while under the pressure of the
atmosphere. In Figure 7 there are two kinds of apparatus shewn, which are
intended for boiling the two kinds of saccharine fluids usually boiled in
vacuum pans, viz, clarified and unclarified saccharine solutions. The appa-
ratus Number One, Figure 7, is intended to be used where boilding molasses or
any
other saccharine fluid that has not been previously clarified by charcoal
or otherwise. The apparatus Number Two, Figure 7, is intended to be used
when the saccharine fluids to be boiled have been previously clarified by.
charcoal or otherwise.
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-
Before describing these apparatus I must refer to a Patent granted to
Morton William Lawerence, Sugar Refiner, on 8th March, 1838, as my
Invention is an improvement thereon. Mr. Lawerence says, "My Invention
in so far as regards the first part of my improvements in the process' of
concentrating certain vegetable juices and saccharine solutions does con-
"sist in first evaporating in an open vessel the juices and solutions before
"described to a point of concentration as near that which I desire them
I ultimately to attain as they can be safely made to attain in such open
"vessels, and then completing the process of concentration by farther evapo-
rating such juices and solutions in vacuo, either with or without the appli-
"cation of heat during such evaporation in vacuo, and whether such last-
" mentioned evaporation be carried on in any close vessel of the kinds now in
use, or in any of the kinds invented by me."
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66
Mr. Lawerence's mode of operation, was as follows:-He boiled a quantity
of any saccharine fluid in an open vessel or caldron until it arrived at or near
the proof point, he then placed over the caldron an air-tight cover (which he
invented for the purpose), and withdrew the air from the caldron, or in other
words produced a vacuum in it, and in this apparatus completed the process of
evaporation. He states in his Specification that the succharine fluid, after
being boiled in the open caldron, might be transferred to a common vacuum
pan, instead of one of the vacuum pans of his invention. Now my mode
of operating differs from Mr. Lawerence's in so far that, instead of warming
a large quantity of any saccharine fluid in an open caldron and then trans-
ferring it to a vacuum pan, I make use of the apparatus No. One or No. Two,
Figure 7th, either of which will raise the saccharine fluid to the necessary
degroe of temperature whilst it is being fed into a vacuum pan. A, B,
No. One, Figure 7th, is an inclined plane; and D, E, F, is the vacuum pan;
C is the feed regulator for the inclined plane; G is à lime-water cistern; and
His a small tank, where the supply of saccharine'fluid is regulated as it flows

page_text: into the pan off the plane. It also serves the useful purpose of allowing the
scum that has been formed on the plane to collect and be removed instead of
letting it go into the vacuum pan. The globular part of the pan, it will be
observed, contains no warm or steam pipes; they might be used in the pan; but
they are not necessary; as the intention of the apparatus is that the fluid to be
boiled should be brought to such a temperature on the inclined plane as will
enable it to carry into the vacuum pan sufficient heat to cause its own. evapo-
ration. The dome D contains a colander L, through which the fluid passes as
it enters the pan; it is thus formed into a hot shower falling in a vacuum; and
very rapid evaporation is the result. In boiling molasses on inclined planes I.
have always found they produce a better sugar than when boiled by the com:
mon vacuum pans; because in boiling on the inclined plane all the scum and
dirt is got out, whereas in the vacuum pan it cannot be got out during the act
of boiling. The fact of being able to get out the dirt of unclarified saccharine
solutions in the form of scum is the chief advantage gained by parboiling thosö
fluids on inclined planes prior to their being let into vacuum pans. The
apparatus No. Two, Figure 7th, is to be used for heating or parboiling saccha
rine solutions that have been previously clarified, and therefore do not require
to be scummed. M, N, is a metal casing to be filled with steam; S is the
inlet cock for steam, and T is the one for letting off condensed water. The
steam casing, M, N, contains a number of tubes through which the saccharine
solution is made to pass on its way to the pan, and thus it is heated or parboiled.
W is the feed pipe communicating with one of the cisterns in a sugar house,
and V is the cock for regulating the feed. I claim the combining of apparatuses,
such as No. One and No. Two, Figure 7th, as above described, with vacuum
pans. The pan Figure 7th is intended to be worked by a system of con-
tinuous filling and continuous emptying, and after it has been fairly set agoing
the proceeding information is sufficient to enable any sugar, boiler to keep it
in operation; but there is a difficulty in starting it, which I shall explain. If
uò provision were made to prevent it some of the liquor that has not been
brought to proof would enter and fill the pipe E, F, but, as already stated,
that part of the pan is constructed on purpose to prevent evaporation in it,
consequently the unboiled liquor admitted to E, F, at the first filling of the
pan, would not be brought to the proper proof for want of evaporation
in that part of the pan; and would require to be drawn off till the pipe by.
working became full of proof sugar. The hollow valve P is intended to obviate
that difficulty; it is just a piece of pipe of the same internal. diameter as (and
is ground like a valve to fit) the pipe E.. When the pan is to be filled for the
first time the hollow. valve P is screwed down by the handle. R till it sits on

page_text: the pipe E; when in that position no liquor can get into the pipe E, but yet
there is free egress to the air that is in the pipe E, through the pipe P, so that
the vacuum can be formed in all parts of the pan, although the sugar at first is
not admitted to the lower part of it. After the first filling of the sugar in the
upper part of the pan is brought to the proof the valve P may be screwed up,
and the ordinary business of filling and emptying the pan go on...
Third Process in the Manufacture of Sugar, videlicit:-The potting or
moulding of the sugar, and .placing it in warm lofts or rooms to drain. There
are two kinds of sugar moulds :-First, common sugar moulds; second, stamp
sugar moulds. Common sugar moulds, as at present used in sugar houses, are
made of two kinds of material, and are called accordingly clay moulds and
sheet-iron moulds. Although made of different materials, both of them are
constructed of the well-known sugar loaf or cone shape. These moulds are
made of various sizes according to the various kinds of sugar to be made in
them, and also a good deal depends on the fancy of the sugar manufacturer.
Figure 8th is a large sized one, commonly called a bastard sugar mould.
Figure 9th is a small sized one, called a loaf mould. These Figures repre-
sent sheet-iron moulds; clay ones are about the same dimensions internally, as
marked in Figures 8th and 9th. The part L, which forms the point or tip in
sheet-iron moulds, is made of cast iron. Common sugar moulds receive a
variety of technical names, according to the kinds of sugar put into them, such
as bastards, pièces, tittlers, lumps; and loaf moulds; but whatever name they
may be known by they are all used as receptacles for the boiled sugar, which
consists of a magma of crystals of sugar intermixed with treacle or syrup, and
that magma
of sugar
is put into them in order that the treacle or syrup may
drain out of it. The treacle or syrup comes out of the mould by a hole L in
the tip, and leaves the sugar in the mould a dry crystalline mass. In order to
facilitate the drainage of the treacle or syrup the moulds are placed in large
lofts or rooms heated by steam; each mould is placed on the top of a pot,
which receives the treacle or syrup.. The length of time that the sugar remains
in these moulds depends on the quality of it. Lumps for crushing remain only
three days in the moulds, but bastard sugar remains a month or six weeks in
the moulds. It is the storing of these moulds side by side on the floors of a
sugar house that compels sugar refiners to build such large houses; some
sugar refiners have as many as twelve and fifteen thousand of these moulds.
Stamp Loaves and Moulds.-These are now seldom niade; the manufacture
of them originated in there being some: years ago a great demand for sugar
loaves weighing from four to seven pounds. These loaves were of too trifling
dimensions for each of them to be made in a separate mould like.common.
*

page_text: loaves. The following is the mode of manufacturing stamp loaves:-The
sugar refiner provides a strong brass or bell-metal die, with a hollow in it of
the shape and size of the loaf which he wishes to make. This is a stamp
mould. The sugar was forced into this mould or die by means of hammers or
a screw press, as follows:-The refiner turned the sugar out of his large
common sugar moulds, in which the sugar had been draining, and while damp
the loaves are shaved, cut, or bruised down to a powder. In this powdered
damp state the sugar is forced into the stamp mould by hammers or a screw
press. It is then taken out and dried, and sold as a small-sized sugar loaf.
I have been thus particular in describing the process of making stamp
loaves, in order to have it clearly understood that the improvements in sugar
moulds, which I am about to describe, do not refer to stamp moulds, but only
to common sugar moulds, where the sugar is run in in a liquid state and
allowed to stand to drain off the syrup or treacle. As I have already stated,
clay and sheet iron are the only kinds of common moulds at present in use in
sugar houses. I have turned my attention to the making of sugar moulds
entirely of cast iron, in consequence of my having discovered that sugar pre-
vents cast iron from rusting; and I claim amongst other improvements the
making and using of sugar moulds formed of cast iron, which I have cast as
light as I can obtain them. For all the coarse kinds of sugar, such as bastards
.and pieces, I find that there is no necessity for coating or covering cast-iron
sugar moulds; but for fine goods, such as loaf moulds, I find they require to
be coated with tin alloys of tin or zinc, or enamel, and therefore I cause them
to be coated in like manner to what other articles of cast iron are done; and I
claim also the coating of cast-iron sugar moulds with those substances.
Common sugar moulds have never been made of any other shape than of
the well-known cone with a circular mouth. Now the circular-shaped mouth
is very great disadvantage, as will be observed by referring to Figure 10th,
where A, A, represent the mouths of four sugar moulds; the space B between
them is entirely lost to the sugar refiner. He, therefore, has to build an
immense house, in order that he may be able to stow away a large quantity of
these moulds side by side on the floors of his sugar house; but yet he con-
structs his moulds of the very worst shape that could be devised for economizing
space.
.
I have invented and introduced into the trade hexagon-shaped moulds.
Figure 11 represents the mouths of three of them. The six-sided polygon or
hexagon mould is not the only polygon that would economize all the space in a
sugar house. The trigon and tetragon polygons would also answer that pur-
pose; but moulds made of those shapes would be weak and liable to break. I

page_text: claim the making and using of polygon-shaped common sugar moulds for
draining syrup or treacle from the crystals of sugar, and the moulds may be
made of any suitable material.
In making cast-iron pots for sugar moulds to sit or stand on they have
hitherto been always painted, and I believe they could not be used like moulds
without paint or a coating of some kind, because many of the syrups that are
put into them are acid, and would act upon the iron; for which reason I cause
such pots to be coated with tin or zinc, or alloy of tin, or with enamel, as is
well understood when coating articles of cast iron for other uses. I claim the
coating of cast-iron pots for sugar moulds to sit upon with tin, or alloys of tin,
or zinc, or with enamel.
In witness whereof, I, the said James Johnston, have hereunto set my
hand and seal, this Eleventh day of November, in the year of our Lord
ne thousand sight hundred and forty-sovon
JAMES (L.s.) JOHNSTON.
AND BE IT REMEMBERED, that on the Eleventh day of November, in
the year of our Lord 1847, the aforesaid James Johnston came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Enrolled the Twenty-seventh day of November, in the year of our Lord
One thousand eight hundred and forty-seven.