D. Peirce.

Observer and record of agriculture, Science and art (Volume v.1) online

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the colouring matter and the cloth, and
when they are actually combined together
in consequence of that affinity. Dying
then, is merely a chemical process and
consists in combining a certain colouring
matter with fibres of cloth. This process
can in no instance be performed, unless
the dye-stuff is first reduced to its integ-
rant particles; for the attraction of aggrega-
tion between the particles of dye-stuffs,
is too great to be overcome by the affinity
between them and the cloth, unless they
be brought within much smaller distances
than is possible while they both remain
in a solid form. It is necessary therefore,
previously to dissolve the colouring mat-
ter in some liquid or other, which has a
weaker affinity for it than the clolh has.
When the cloth is dipped into this solu-
tion, the colouring matter, reduced by this
contrivance to a liquid state is brought
within the attracting distance, the cloth
therefore acts upon it and from its stronger
affinity takes it from the solvent, and fixes
upon itself. By this contrivance too, the
equlity of the colour, is in some measure
secured, as every part of the cloth has an
opportunity of attracting to itself the pro-
per proportion of colouring particles. The
facility with which cloth imbibes a dye
depends upon two circumstances, namely,
the affinity between the cloth and the dye-
stuff, and the affinity between the dye-
stuff and its solvent. It is directly as the
former and inversely as the latter.

It is ol importance to preserve a due
proportion between these two affinities as
upon that proportion much of the accu-
racy of dying depends. If the affinity
between the colouring matter and the
cloth be too great, compared with the af-
finity between the colouring matter and
the solvent, the cloth will take the dye
too rapidly, and it will be scarcely possir
bleto prevent its colour from being une-



qual. On ihe other hand, if the affinity
between the colouring matter, and the
solvent be too great, compared with that
between the colouring matter and the
cloth, the ciotli will either not take the
colour at all, or it will take it very slowly
and very faintly.

Wool has the strongest affinity for al-
most all colouring matters, silk the next
strongest, cotton a considerably weaker
affinity, and linen the weakest affinity of

In order, therefore, to dye cotton, or
linen, the dye-stuff should in many cases
be dissolved in substances for which it has
a weaker affinity than for the solvent em-
ployed in the dying of wool or silk. Thus
we may use oxide of Iron dissolved in sul-
])huric acid, in order to dye woof: but for
cotton or linen, it is better to dissolve it in
acetous acid. Were it possible to procure
a sufficient number of colouring mitters,
having a strong affinity for cloth to an-
swer all the purposes of dying, that art
would be exceedingly simple and easy.
But this is by no means the case; if we
except indigo, the dyer is scarcely pos-
sessed of a dye-stufT which yields of it-
self a good colour, sufficiently permanent
to deserve the name of a d3'e.

This difficulty, which at first sight ap-
pears insurmountable has been obviated
by a very ingenious contrivance. Some
subsiance is employed which has a strong
affinity both for the cloth and the colour-
ing matter. This sub-stance is previously
combined with the cloth which is then
dipped in tbesolulion containing the dye-
stuff. The dye-stuff combines with the
intermetliate substance, which being firm-
ly combined with the cloth secures the
permanence of the dye. Substances em-
ployed for this purpose are denominated
mordants. The most important part of
dying is undoubtedly the proper choice,
and proper application of mordants; as up-
on them, the permanency of almost every
dye depends. Every thing whieli has
been said respecting the npplic:Uion of
colourinj5 matters applies equally to the
application of mordants. 'Ihey must be
previously dissolved in some liquid, which
has a weaker affinity for them than the
cloth has, to which they are to be applied;
and the cloth must be dipped; or even
steeped in this solution, in order to be

saturated with the mordant. Almost the
only subsiance used as mordants are
earths, metalic oxides, tan and oil. Of ear-
thy morxlants the most important and most
genei'ally used, is is used either
in the state of common alum, in which
it is combined wiih sulphuric acid or in
that of acetate of alumina. Alum when
used as a mordant, is dissolved in water,
and very fr-equently a quantity of tartar
is dissolved along with it.

Into this solution the cloth is put, and
kept in it till it has absorbed as much al-
umina as is necessary. It is then taken
out, and for the most part washed and
dried. It is now a good deal heavier than
it was befor-e, owing to the alumina which
has combined with it. The tartar serves
two purposes; the potass which it contains
combines with the sulphuric acid of the
alum, and thus prevents that very corro-
sive substance fr-om injuring the texture
of the cloth, which otherwise might hap-
pen, the tartarous acid on the other hand,
combines with part of the alumina and
forms a tartrate of alumina which is more
easily decomposed by the cloth than alum.
Acetate of aluinina has also been used in
dying. This mordant is now prepared
by pouring acetate of lead into a solution
of alum; a dou!>le decomposition takes
place, the sulphurous acid combines with
the lead, and the compound precipitates,
in the form of an insoluble powder, while
the alumina combines wiih the acetous
acid, and remains dissolved in the liquid.
I'his mordant is employed for cotton and
linen, which have a weaker affinity than
wool for alumina. It answers much bet-
ter than alum; Ihe cloth is much easier
satur-ated with alumina and takes in con-
sequence, both a richer and more perma-
nent colour.

( To be continued.)


iiaiTuel's Method.

\sl. proces.^. To wash the roots and
cut off the topi.

2. To reduce the root to a pulp, this
may be done in various ways; two indent-
ed cylinder's, one working within the
other is considered the best.

3. To express the juice. This should
be done as speedily as possible, for the



Juice alters very rapidly, and becomes
more and more mucilaginous, to the in-
jury of the future operations. 100 parts
of beets give from 65 to 70 of juice.

4. To neutralize the acid and evap-
orate. When the juice begins to boil,
some chalk is stirred in as long as there
is any effervesence. It is then scummed,
boiled down sufficiently and the syrup
transferred to conical moulds for six or
seven days to deposit its earthy salts.

5. To clarify and boil down. The
syrup is clarified either with skimmed
milk or blood, and then strained and
boiled down.

6. To crystallize the sugar. This is the
longest process. It is done in square shal-
low earthen, or tinned iron vessels, kept
in a stoved chamber, the heal of which is
steadily maintained at 90° to 95° Fahr.

The sugar does not begin to crystallize
in less than six or seven days. The cr)'S-
tals form a crust at the top of the liquor
and the sides of the vessels, which con-
tinue to form as long as the liquor retains
any sugary taste. In about 25 or 30 days
the crj'stallization ceases, and the fluid
which remains has a saline and unpleasant
flavour. The crystallized crusts are col-
lected and cautiously pressed in a sack,
and then yield the first rough Muscovado
which is stoved for ten or twelve hours,
and is fit for the common uses of Musco
cane sugar.

By these processes 74 kilogammcs of
Muscovado is obtained from 5000 kilo-
grammes of beet root. (The kilogram-
me is equal to about 35^ oz. avoirdupoise
or 2.205 lbs.) The Muscovado is thes fit
for further refining by claying, (§'C. in the
usual manner, in which it loses about 1-8
of its weight to be reduced to saleable
loaf sugar.

Some observations may be added on the
cultivation of the beet. It requires a
light dry sandy soil. The seeds are sown
in April or May, and the plants require
much weeding and thinning.

When they have acquired their full
size, which is from October to November,
the tops are headed off", and serve as fod-
der for cattle, and the earth is turned
down from round the top of the root to
give access to the sun, which improves
the quality of the j'uice. The root is then

dug up and left for a few da)^s on the sur-
face before it is stored. It should be kept
in a dry place. One arpent of ground
should produce al least 15000 kilogram-
mes of roots.

The expense of cultivating the beet and
manufacturing sugar in the great way
(including machinery buildings, labour,
rent of land 4'c. ^'c. estimating the inter-
est of" the cost of building and machinery
and wear or annual depreciation,) is con-
sidered to avarage 98 centimes (^100
centimes make a franc ) for each killo-
gramme of Muscovado, and every killo-
gramme of refined sugar will cost one
frank 40 centimes.

Kirchoff's Mcihoil.
Take 100 pounds of starch, 400 of
water, 1 lb. of sulphuric acid, and suffi-
cient powdered charcoal and chalk. First
mix half the water v/ith the sulphuric
acid and bf)il it in a well tinned copper;
rub the starch with the rest of the water;
pass it through a sieve: and add- it by six
ounces at a lime, to the boiling dilute sul-
phuric acid. When the whole is added,
continue the boiling for thirty-six hours,
adding more water in- the room of that
which is boiled away, then add some
charcoal powder, and chalk sufficient to
saturate the acid, and pass the liquor
through a linen cloth, which is now
clear and sweet. Evaporate it by a gentle
heat to the consistence of syrup, when
the sulphate of lime will crystallize.
Again strain the liquor, and set it by to
crystallize, when the sugar will separate
in about three days. Press the rough sugar
with care so as to free it from the syrup,
and by re-dissolving and again crystalli-
zing the raw sugar, it will become very
fine and good.

Sulphuric acid in any proportion will
convert starch into sugar, but if the quan-
tity of acid is increased more water must
be added, and especially the boiling should
be continued long'r which in every case
remarkably promotes the subsequent crys-
tallization. The nitric, muriatic, and ox-
alic acids, will equally convert starch into
sugar, but not the acetous, phosphoric, or
tartarous acids.



Another Process is Ikus described:

Bullion La Grange's Melliod.

Some starch is first well washed with
rohl water to remove any accidental sac-
chniine or extractive matter, and well
(liied. Two kilogrammes of this starch
lubbed down with eight kilogrammes of
river water acitlulatcd with forty grammes
oi' concentrated sulphutic acid, are boiled
lor thiity-six hours in a silver basin. For
the first hour the mixture is stirred con-
htaiitly to keep it from burning, but after-
wai'ds, as it becomes thinner, only occa-
sionally. Water is from time to time
to be added, to supply the waste by
boiling. After boiling, the whole is
clarified with charcoal and chalk, and
filtrated through a woollen cloth. The li-
quor is then evaporated nearly to a syrup,
and let cool, to allow some of (he sulphate
of lime to settle; after which the clear
syrup is boiled down to a thick consis-
tence. This syrup is much clearer and
sweeter when prepared in a silver vessel
than in one of tinned copper; indeed, the
latter material can hardly be used on ac-
count of the action of the acid upon the
tin by the long boiling; but a leaden, boil-
er muy be employed with advantage. The
quantity of rich syrup given in this pro-
cess is about equal to that of the starch
employed; and M. Vogel obtained the
same results with twice the proportion of
acid and only eight hours boiling. As
several vegetable substances have a deci-
dedl};^ sweet taste but without containing
an)' real sugar that can be extracted from
them, M. Vogel tried to produce the vi-
nous fermentation in the starch sugar. A
quantity of it was mixed with warm water
and leaven, the fermentation soon took
place, much carbonic acid was given out,
and the fermented liquor gave by distilla-
tion, a sensible quantity of alcohol. The
most highly saccharine starch syrup, slow-
ly stoved in tin plate moulds, gave a per-
fectly transparent elastic matter like the
paste of jujubes, which attracted moisture
from the air. A similar saccharine gummy
mass was obtained from potato starch.
This mass was further analysed by boiling
with alcohol, which left undissolved about
a fifth of the whole as a very viscous mat-
ter, that became friable when dry, and
pgain dissolved by cold water into a thick
jnucilage insoluble in alcohol. In these

properties it closely resembled gum-arabic
but differed from this gum in not forming
the mucous acid when treated with nitric
acid. The gummy matter of the starch
syrup has been considered by some as a
compound of starch, water and sulphuric
acid; but JM. Vogel shows clearly that it
does not contain any of this acid, neither,
indeed, does the saccharine part, soluble
in alcohol, give any indications of sulphu-
ric acid. These experiments led the au-
thor to examine the action of the diluted
mineral acids upon other substances. Su-
gar of milk was selected, as being in its
natural state incapable of entering into the
vinous fermentation: one hundred gram-
mes of sugar of milk were boiled for three
hours with four hundred gramn)es of wa-
ter and two grammes of strong sulphuric
acid, adding water to supply the waste.
The excess of acid was then neutralized
by chalk, and the liquor when strained
was clear, but slightly coloured. Slowly
evaporating, it left a thick brown syrup
which in a few days thickened to a crys-
talline mass of a rich sweet taste, much
more than the sugar of milk itself^ and.
soluble in alcohol, in which too it diflfers
from sugar of milk. This crystalline mass
very readily entered into fermentation,
when properly diluted, and the fermented
liquor yielded a considerable proportion
of alcohol. The experiment was repeated
with 3, 4, and 5 parts of sulphuric acid,
and with equal success, the crj'stalline
mass being always highly saccharine and

Muriatic acid was found to have the same
efiect with the Sulphuric, in changing the
sugar of milk into an extremely rich,
sweet, fermentable syrup. — Nitric Acid
on the other hand, and radical vinegar,
produce no change. — Such are the facts of
the singular conversion of starch or sugar
of milk into an intensely sweet fermentable
saccharine mass, though it does not appear
that perfect crystallized sugar has yet
been obtained in this way. The theory of
this operation is very difficult of explana-
tion. Some have thought that the mere
continuance of heat efiected the change,
but the author boiled starch and water alone
for four successive days, and at the end, a
very liquid mass was obtained, which
when slowly dried left a thick bitter mu-
cilage without the smallest saccharine



taste. It becomes a question whether the
Sulphuric Acid is decomposed in the
process. For this purpose M. I^a Grange,
took a given weight of sugar of milk, and
Sulphuric Acid and water, boiled them for
three hours in a retort, and the distilled
liquor was carefully examined by Barytes,
Litmus, and other tests, but neither the
sulphuric acid, sulphurous, acetic, nor
carbonic acid was produced, the liquor
being pure water. Afterwards on satura-
ting the acid contents of the retort with a
known weight of potash, and evaporating
the whole to dryness, the dry mass was less
by about an eighth part, than the united
weights of the sugar of milk and the
sulphate of potash, produced by the Sul-
phuric Acid and the alkali employed.
This loss of weight must therefore be ac-
counted for, in the water distilled over, as
no gas whatever was generated in the pro-

Hence La Grange supposes, that the
operation of the Sul])huric Acid is to
disengage from the starch or sugar of milk,
so much hydrogen and oxygen, as will
produce water, and that the loss of these
principles, converts the remainder into
a saccharine matter.

On the Sugar from Potato Starch.

By Dr. Tulhill.

A very interesting experiment on this
subject is related by Dr. Tuthill. One
pound and a half of potato starch was
mixed with six pints of distilled water,
and a quarter of an ounce by weight, oi
common sulphuric acid, in a common cov-
ered earthen vessel. — The mixture was
kept boiling for thirty-four hours with-
out intermission, fresh water being occa-
sionally added to supply the waste by
evaporation. At the end of twenty-four
hours the liquor had become sensibly
saccharine, and this quality continued to
increase as the boiling was prolonged.

At the end of thirty-four hours, half an
ounce of finely powdered charcoal was
added, and the boiling continued two
hours longer. The acid was then satura
ted by lime, and the boiling continued for
another half hour, after which the liquid
was strained through calico, and the resi-
due in the filter washed with warm water.
This residue, when dry, weighed I of an
ounce, and was charcoal and sulphate of

lime. The clear liquor was then evapo-
rated in a water bath to the consistence of
syrup, and set aside to crystallize. In
eight days it congealed into a crystalline
mass, tasting like common brown sugar
with treacle. One pound of this sugary
matter was then redissolved in four pounds
of water, a quarter of an ounce of yeast
added, and the mixture set to ferment. In
ten days the fermented liquor began to
smell sourish, and was immediately distil-
led. A pint and a half of the first run-
nings were alone collected, which redistil-
led, gave a weak ardent spirit, which from
its specific gravity was found by Blagden's
Tables, to contain 14 drams by measure
of proof spirit.

The whole quantities used, and the pro-
duct were S| lbs. of potatoes, yielding 1^
lbs. starch, which gave 1^ lb. of dry saccha-
rine matter, from which, after fermenta-
tion, as much ardent spirit was extracted
as would equal 14 drams, by measure, of
proof spirit.

Observations on the three preceding

M. KirchofF's curious discovery of the
conversion of starch into sugar, by the
agency of sulphuric acid, is fully confirm-
ed by these experiments, but the explana-
tion of this singular change is very ob-
scure. — By a late analysis of several kinds
of vegetable matter, through the agency
of oxy muriate of potash, by Messrs. Gay
l^ussac and Thenard, these eminent Chem
ists think that they have established the
following facts, viz:

1st. That a vegetable substance is always
acid when the oxygen which it contains
is in a greater proportion to the hydrogen
than that which constitutes water.

2nd. That the vegetable substance is al-
ways resinous or oily, or alcoholic, when
ihe oxygen is in a less proportion to the
hydrogen, than to constitute water.

" 3d. That the vegetable substance is an
alogous to sugar, starch, gum, ligneous

Online LibraryD. PeirceObserver and record of agriculture, Science and art (Volume v.1) → online text (page 5 of 35)